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TCID	Name	Organismal Type	Example
3.A.1.1: The Carbohydrate Uptake Transporter-1 (CUT1) Family
3.A.1.1.1	Maltooligosaccharide porter. The 3-D structure has been reported by Oldham et al. (2007). An altering access mechanism has been suggested for the maltose transporter resulting from rigid-body rotations (Khare et al., 2009). Bordignon et al. (2010) and Schneider et al. (2012) have reviewed the extensive knowledge available on MalEFGK, its mode of action and its regulatory interactions. The transporter sequesters the MalT transcriptional activator at the cytoplasmic surface of the membrane in the absence of the transport substrate (Richet et al. 2012).	Proteobacteria	MalEFGK of E. coli MalE (receptor [R]) MalF (membrane [M]) MalG (membrane [M]) MalK (cytoplasmic [C])
3.A.1.1.2	The putative arabinogalactan oligomer porter, GanOPQ (MalEFG) The energizing ATPase is probably MsmX (see 3.A.1.1.26)	Bacteria	GanOPG of Bacillus subtilis YufK or GanO (R) (O07009) YufL or GanP (M) (O32261) YufM or GanQ (M) (O07011) MsmX (C) (see 3.A.1.1.26)
3.A.1.1.3	Glycerol-phosphate porter. Transports both glycerol-3-P and glycerol-3-P diesters including glycerophosphocholine but not glycerol-2-P (Yang et al. 2009; Wuttge et al. 2012). UgpB (the receptor) binds glycerol 3-P with high affinity, but not glycerol 2-P (Wuttge et al. 2012). UgpB (the receptor) binds glycerol 3-P with high affinity, but not glycerol 2-P (Wuttge et al. 2012).	Proteobacteria	UgpABCE of E. coli UgpB (R) UgpA (M) UgpE (M) UgpC (C)
3.A.1.1.4	Lactose porter	Proteobacteria	LacEFGK of Agrobacterium radiobacter LacE (R) LacF (M) LacG (M) LacK (C)
3.A.1.1.5	Hexitol (glucitol; mannitol) porter	Proteobacteria	SmoEFGK of Rhodobacter sphaeroides SmoE (R) SmoF (M) SmoG (M) SmoK (C)
3.A.1.1.6	Cyclodextrin porter	Proteobacteria	CymDEFG of Klebsiella oxytoca CymE (R) CymF (M) CymG (M) CymD (C)
3.A.1.1.7	Maltose/trehalose porter	Euryarchaeota	MalEFGK of Thermococcus litoralis MalE (R) MalF (M) MalG (M) MalK (C) (not sequenced)
3.A.1.1.8	Sucrose/maltose/trehalose porter (sucrose-inducible)	Proteobacteria	AglEFGK of Sinorhizobium meliloti AglE (R) AglF (M) AglG (M) AglK (C)
3.A.1.1.9	The oligosaccharide (glucuronate-linked to a xylo-oligosaccharide) ABC uptake porter, GuoEFGK in AguEFGK. GuoE binds with high affinity a four sugar aldotetrouronic acid [2-O-α-(4-O-methyl-α-D-glucuronosyl)-xylotriose] (Shulami et al., 1999; S.Shulami, personal communication)	Bacteria	GuoEFGK of Geobacillus stearothermophilus AguE or GuoE (R) (C9RT46) AguF or GuoF (M) (Q09LY7) AguG or GuoG (M) (Q09LY6) AguK or GuoK (C) (not identified)
3.A.1.1.10	Alginate (MW 27,000 Da) (and Alginate oligosaccharides) uptake porter. Sphingomonas species A1 is a 'pit-forming' bacterium that directly incorporates alginate into its cytoplasm through a pit-dependent transport system, termed a 'superchannel' (Murata et al., 2008). The pit is a novel organ acquired through the fluidity and reconstitution of cell surface molecules, and through cooperation with the transport machinery in the cells. It confers upon bacterial cells a more efficient way to secure and assimilate macromolecules (Murata et al., 2008).	Proteobacteria	AlgSM1M2Q1Q2 of Sphingomonas sp.A1 AlgS (C) AlgM1 (M) AlgM2 (M) AlgQ1 (R) AlgQ2 (R)
3.A.1.1.11	Saturated and unsaturated oligogalacturonide transporter, TogMNAB (transports di- to tetrasaccharide pectin degradation products which consist of D-galacuronate, sometimes with 4-deoxy-L-threo-5-hexosulose uronate at the reducing end of the oligosaccharide) (Hugouvieux-Cotte-Pattat et al. 2001). Regulated by pectin utilization regulator KdgR (Rodionov et al. 2004)	Proteobacteria	Oligogalacturonide transporter TogMNAB of Erwinia chrysanthemi TogM (M) TogN (M) TogA (C) TogB (R)
3.A.1.1.12	Palatinose (isomaltulose; 6-O-α-D-glucopyranosyl-D-fructose) uptake porter	Proteobacteria	PalEFGK of Erwinia rhapontici PalE (R) PalF (M) PalG (M) PalK (C)
3.A.1.1.13	Glucose, mannose, galactose porter	Crenarchaeota	GlcSTUV of Sulfolobus solfataricus GlcS (R) GlcT (M) GlcU (M) GlcV (C)
3.A.1.1.14	Arabinose, fructose, xylose porter	Crenarchaeota	AraSTUV of Sulfolobus solfataricus AraS (R) AraT (M) AraU (M) AraV (C)
3.A.1.1.15	Trehalose porter	Crenarchaeota	TreSTUV of Sulfolobus solfataricus TreS (R) TreT (M) TreU (M) TreV (C)
3.A.1.1.16	Maltooligosaccharide porter (Maltose is not a substrate, but maltotriose is.)	Euryarchaeota	PF1933, 1936, 1937, 1938 of Pyrococcus furiosus PF1938 (R) PF1937 (M) PF1936 (M) PF1933 (C)
3.A.1.1.17	Trehalose/maltose/sucrose porter (trehalose inducible)	Proteobacteria	ThuEFGK of Sinorhizobium meliloti ThuE (R) ThuF (M) ThuG (M) ThuK (C)
3.A.1.1.18	N-Acetylglucosamine/N,N'-diacetyl chitobiose porter (NgcK (C) not identified)	Actinobacteria	NgcEFG of Streptomyces olivaceoviridis NgcE (R) NgcF (M) NgcG (M)
3.A.1.1.19	Platinose (isomaltulose) (6-O-α-D-glucopyranosyl-D-fructofuranose) porter	Proteobacteria	PalEFGK of Agrobacterium tumefaciens PalE (R) PalF (M) PalG (M) PalK (C)
3.A.1.1.20	The fructooligosaccharide porter, MsmEFGK (Barrangou et al., 2003)	Bacteria	MsmEFGK of Lactobacillus acidophilus MsmE (R) AAO21856 MsmF (M) AAO21857 MsmG (M) AAO21858 MsmK (C) AAO21860
3.A.1.1.21	The xylobiose porter; BxlEFG(K) (Tsujibo et al., 2004)	Bacteria	BxlEFGK of Streptomyces thermoviolaceus BxlE (R) CAB88161 BxlF (M) CAB88162 BxlG (M) CAB88163 BxlK (C) Unknown
3.A.1.1.22	The maltose, maltotriose, mannotetraose (MalE1)/maltose, maltotriose, trehalose (MalE2) porter (Nanavati et al., 2005). For MalG1 (823aas) and MalG2 (833aas), the C-terminal transmembrane domain with 6 putative TMSs is preceded by a single N-terminal TMS and a large (600 residue) hydrophilic region showing sequence similarity to MLP1 and 2 (9.A.14; e^-12& e^-7) as well as other proteins.	Thermotogae	MalE1E2FGK of Thermotoga maritima MalE1 (R) (binds maltose, maltotriose and mannotetraose) (AAD36279) MalE2 (R) (binds maltose, maltotriose and trehalose) (AAD36901) MalF1 (M) (AAD36278) MalG1 (M) (AAD36277) [MalG2 (M) (AAD36899] MalK (C) (AAD36351)
3.A.1.1.23	The cellobiose/cellotriose (and possibly higher cellooligonucleosides), CebEFGMsiK [MsiK functions to energize several ABC transporters including those for maltose/maltotriose and trehalose] (Schlösser et al., 1997, Schlösser et al., 1999)	Bacteria	CebEFGMsiK of Streptomyces reticuli CebE (R) (CAB46342) CebF (M) (CAB46343) CebG (M) (CAB46344) MsiK (CAA70125)
3.A.1.1.24	The glucose/mannose porter TTC0326-8 plus MalK1 (ABC protein, shared with 3.A.1.1.25) (Chevance et al., 2006).	Bacteria	TTC0326-8 MalK1 of Thermus thermophilus TTC0326 (M) - Q72KX4 TTC0327 (M) - Q72KX3 TTC0328 (R) - Q72KX2 MalK1 or TTC0211 (C) - Q72L52
3.A.1.1.25	The trehalose/maltose/sucrose/palatinose porter (TTC1627-9) plus MalK1 (ABC protein, shared with 3.A.1.1.24) (Chevance et al., 2006).	Bacteria	TTC1627-9 + MalK1 of Thermus thermophilus TTC1627 (R) (Q72H68) TTC1628 (M) (Q72H67) TTC1629 (M) (Q72H66) MalK1 (TTC0211) (C) (Q72L52)
3.A.1.1.26	The maltose porter, MdxEFG and MsmX (Ferreira and Sá-Nogueira, 2010)	Bacteria	The maltose porter of Bacillus subtilis, MalEFG/MsmX. MalE (R) - O06989 MalF (M) - O06990 MalG (M) - O06991 MsmX (C) - P94360
3.A.1.1.27	Maltose/Maltotriose/maltodextrin (up to 7 glucose units) transporters MalXFGK (MsmK (3.A.1.1.28) can probably substitute for MalK; Webb et al., 2008).	Bacteria	MalXFGK of Streptococcus mutans: MalX (R) (Q8DT28) MalF (M) (Q8DT27) MalG (M) (Q8DT26) MalK (C) (Q8DT25)
3.A.1.1.28	The raffinose/stachyose transporter, MsmEFGK (MalK (3.A.1.1.27) can probably substitute for MsmK; Webb et al., 2008).	Bacteria	MsmEFGK of Streptococcus mutans: MsmE (R) (Q00749) MsmF (M) (Q00750) MsmG (M) (Q00751) MsmK (C) (Q00752)
3.A.1.1.29	Aldouronate transporter, LplA,B,C (Chow et al., 2007)	Bacteria	LplABC of Paenibacillus sp. JDR-2: LplA (R)(A9QDR6) LplB (M)(A9QDR7) YtcP (M)(A9QDR8) LplC - not identified
3.A.1.1.30	Glucose porter, GtsABCD (del Castillo et al., 2008).	Bacteria	The glucose porter of Pseudomonas putida, GtsABCD: GtsA (R) (Q88P38) GtsB (M) (Q88P37) GtsC (M) (Q88P36) GtsD (C) (Q88P35)
3.A.1.1.31	The trehalose-recycling ABC transporter, LpqY-SugA-SugB-SugC (essential for virulence) (Kalscheuer et al., 2010).	Bacteria	LpqY-SugA-SugB-SugC of Mycobacterium tuberculosis LpqY (R) (Q7D8J9) SugA (M) (O50452) SugB (M) (O50453) SugC (C) (O50454)
3.A.1.1.32	The glucosylglycerol uptake transporter (functions in osmoprotection and also transports sucrose and trehalose (Mikkat and Hagemann, 2000) (most similar to 3.A.1.1.8).	Bacteria	GgtABCD of Synechocystis sp. strain PCC6803 GgtA (C) (Q55035) GgtB (R) (Q55471) GtC (M) (Q55472) GgTD (M) (Q55473)
3.A.1.1.33	The N,N'-diacetylchitobiose uptake transporter, DasABC/MsiK (MsiK energizes several ABC transporters (see 3.A.1.1.23)) (Saito et al., 2008)	Bacteria	DasABC MsiK of Streptomyces coelicolor DasA (R) (Q8KN19) DasB (M) (Q8KN18) DasC (M) (Q8KN17) MsiK (C) (Q9L0Q1)
3.A.1.1.34	The arabinosaccharide transporter AraNPQMsmX. Transports α-1,5-arabinooligosaccharides, at least up to four L-arabinosyl units; the key transporter for α-1,5-arabinotriose and α-1,5-arabinotetraose, but not for α-1,5-arabinobiose which is transported by AraE. MsmX is also used by the MdxEFG-MsmX system (3.A.1.1.36) (Ferreira and S�-Nogueira, 2010).�	Bacteria	AraNPQ-MsmX of Bacillus subtilis AraN (R) (P94528) AraP (M) (P94529) AraQ (M) (P94530) MsmX (C) (P94360)
3.A.1.1.35	Glycerol uptake porter, GlpSTPQV (Ding et al., 2012).	α-proteobacteria	GlpSTPQV of Rhizobium leguminosarum GlpS (C) (G3LHY8) GlpT (C) (G3LHY9) GlpP (M) (G3LHZ0) GlpQ (M) (G3LHZ1) GlpV (R) (G3LHZ3)
3.A.1.1.36	Putative transport system	Actinobacteria	Putative transport system of Streptomyces coelicolor Q93J94 (R) Q93J93 (M) Q93J92 (M) Q9L0Q1 (C?)
3.A.1.1.37	Predicted arabinoside porter. Regulated by arabinose-responsive regulator AraR (Rodionova et al. 2012).	Thermotogae	AraEFG of Thermotoga maritima AraE (R) (TM0277) - AraF (M) (TM0278) Q9WYB4 AraG (M) (TM0279) Q9WYB5
3.A.1.1.38	Inositol phosphate porter (D.A. Rodionov, personal communication). Binds inositol phosphate with low Kd and inositol with less affinity.	Thermotogae	InoEFGK of Thermotoga maritima InoE (R) TM0418 (Q9WYP9) InoF (M) TM0419 (Q9WYQ0) InoG (M) TM0420 (Q9WYQ1) InoK (C) TM0421 (Q9WYQ2)
3.A.1.1.39	Alpha-1,4-digalacturonate porter (Nanavati et al., 2006). Regulated by pectin utilization regulon UxaR (Rodionova et al. 2012).	Thermotogae	AguEFG of Thermotoga maritima AguE (R) (TM0432) (Q9WYR3) AguF (M) (TM0431) (Q9WYR2) AguG (M) (TM0430) (Q9WYR1)
3.A.1.1.40	Predicted chitobiose porter. Regulated by chitobiose-responsive regulator ChiR (Kazanov et al., 2012).	Thermotogae	ChiEFG of Thermotoga maritima ChiE (R) (TM0810) (Q9WZR7) ChiF (M) (TM0811) (Q9WZR8) ChiG (C) (TM0812) (Q9WZR9)
3.A.1.1.41	Trehalose porter. Also binds sucrose (Boucher and Noll, 2011). Induced by glucose and trehalose. Directly regulated by trehalose-responsive regulator TreR (Kazanov et al., 2012).	Thermotogae	TreG (M) (ThemaDRAFT_1378) G4FGN6 TreF (M) (ThemaDRAFT_1379) G4FGN7 TreE (R) (ThemaDRAFT_1380) G4FGN8
3.A.1.2: The Carbohydrate Uptake Transporter-2 (CUT2) Family
3.A.1.2.1	Ribose porter (RbsC has 10 TMSs with N- and C-termini in the cytoplasm (Stewart and Hermodson, 2003))	Proteobacteria	RbsABC of E. coli RbsA (C) RbsB (R) RbsC (M)
3.A.1.2.2	Arabinose porter	Proteobacteria	AraFGH of E. coli AraF (R) AraG (C) AraH (M)
3.A.1.2.3	Galactose/glucose (methyl galactoside) porter	Proteobacteria	MglABC of E. coli MglA (C) MglB (R) MglC (M)
3.A.1.2.4	Xylose porter	Proteobacteria	XylFGH of E. coli XylF (R) XylG (C) XylH (M)
3.A.1.2.5	Multiple sugar (arabinose, xylose, galactose, glucose, fucose) putative porter	Proteobacteria	ChvE, GguAB of Agrobacterium tumefaciens ChvE (R) GguA (C) GguB (M)
3.A.1.2.6	D-allose porter	Proteobacteria	AlsABC of E. coli AlsB (R) AlsA (C) AlsC (M)
3.A.1.2.7	Fructose/mannose/ribose porter	Proteobacteria	FrcABC of Sinorhizobium meliloti FrcA (C) FrcB (R) FrcC (M)
3.A.1.2.8	AI2 autoinducer porter (Taga et al., 2001, 2003)	Proteobacteria	LsrACDB of E. coli LsrB (R) AAC74589 LsrA (C) AAC74586 LsrC (M) AAC74587 LsrD (M) AAC74588
3.A.1.2.9	Rhamnose porter (Richardson et al., 2004) (Transport activity is dependent on rhamnokinase (RhaK; AAQ92412) activity (Richardson and Oresnik, 2007) This could be an example of group translocation!)	Proteobacteria	RhaSTP of Rhizobium leguminosarum bv. trifolii RhaS (R) AAQ92407 RhaT (C) AAQ92408 RhaP (M) AAQ92409
3.A.1.2.10	The purine nucleoside permease (probably transports guanosine, adenosine, 2'-deoxyguanosine, inosine and xanthosine with decreasing affinity in this order) (Deka et al., 2006)	Spirochaetes	PnrA-E of Treponema pallidum PnrA (R) (TmpC; Tp0319) (P29724) PnrB (?51 aas; 1 TMS; Tp0320) (O83340) PnrC (C) (533 aas; duplicated; Tp0321) (NP_218761) PnrD (M) (400 aas; 10 TMSs; Tp0322) (NP_218762) PnrE (M) (316 aas; 10 TMSs; Tp0323) (NP_218763)
3.A.1.2.11	The erythritol permease, EryEFG (Geddes et al., 2010) (probably orthologous to 3.A.1.2.16)	Bacteria	EryEFG of Sinorhizobium meliloti EryE (C) (CAC48737) EryF (M) (CAC48738) EryG (R) (CAC48735)
3.A.1.2.12	The (deoxy)ribonucleoside permease; probably takes up all deoxy- and ribonucleosides (cytidine, uridine, adenosine and toxic analogues, fluorocytidine and fluorouridine tested), but not ribose or nucleobases (Webb and Hosie, 2006)	Bacteria	RnsABCD of Streptococcus mutans RnsA (R) (AAN58814) RnsB (C) (AAN58813) RnsC (M) (AAN58812) RnsD (M) (AAN58811)
3.A.1.2.13	The probable autoinducer 2 (AI2) uptake porter (Shao et al., 2007) (50-70% identical to RbsABC of E. coli; TC# 3.A.1.2.1)	Bacteria	RbsABC of Aggregatibacter actinomycetemcomitans (Actinobacillus succinogens) RbsA(C) (A6VKS8) RbsB(R) (A6VKT0) RbsC(M) (A6VKS9)
3.A.1.2.14	Putative L-arabinose porter (Rodionov et al. 2010).	Proteobacteria	AraUVWZ of Shewanella oneidensis AraU (R) (Q0HIQ8) AraV (C-C) (Q0HIQ7) AraW (M; 10 TMSs) (Q0HIQ6) AraZ (M; 9 TMSs) (Q0HIQ5)
3.A.1.2.15	The putative xylitol uptake porter, XltABC (Rodionov et al., 2010)	Proteobacteria	XltABC of Shewanella pealeana XltA (C) (A8H4W7) XltB (M; 9 TMSs) (A8H4W6) XltC (R) (A8H4W5)
3.A.1.2.16	The erythritol uptake permease, EryEFG (Yost et al., 2006) (probably orthologous to 3.A.1.2.11)	Bacteria	EryEFG of Rhizobium leguminosarum EryE (C) (Q1M4Q7) EryF (M) (Q1M4Q8) EryG (R) (Q1M4Q9)
3.A.1.2.17	General nucleoside uptake porter, NupABC/BmpA (transports all common nucleosides as well as 5-fluorocytidine, inosine, deoxyuridine and xanthosine) (Martinussen et al., 2010) (Most similar to 3.A.1.2.12). NupA is 506aas with two ABC (C) domains. NupB has 8 predicted TMSs, NupC has 9 or 10 predicted TMSs in a 4 + 1 (or2) + 4 arrangement.	Bacteria	NupABC/BmpA of Lactococcus lactis BmpA (R) (D2BKA1) NupA (C) (A2RKA7) NupB (M) (A2RKA6) NupC (M) (A2RKA5)
3.A.1.2.18	Xylose porter (Nanavati et al. 2006). Regulated by xylose-responsive regulator XylR (Kazanov et al., 2012).	Thermotogae	XylFEK of Thermotoga maritima XylF (M) (TM0112) (Q9WXW7) XylE (R) (TM0114) (Q9WXW9) XylK (C) (TM0115) (Q9WXW0)
3.A.1.2.19	D-ribose porter (Nanavati et al., 2006). Induced by ribose (Conners et al., 2005).	Thermotogae	RbsABC of Thermotoga maritima RbsA (C) (TM0956) (Q9X051) RbsB (R) (TM0958) (Q9X053) RbsC (M) (TM0955) (Q9X050)
3.A.1.2.20	Glucose porter. Also bind xylose (Boucher and Noll 2011). Induced by glucose (Frock et al. 2012). Directly regulated by glucose-responsive regulator GluR (Kazanov et al., 2012).	Thermotogae	GluEFK of Thermotoga maritima GluE (C) (ThemaDRAFT_1377) (G4FGN5) GluF (C) (ThemaDRAFT_1376) (G4FGN4) GluK (C) (ThemaDRAFT_1375) (G4FGN3)
3.A.1.2.21	The myoinositol (high affinity)/ D-ribose (low affinity) transporter IatP/IatA/IbpA. The structure of IbpA with myoinositol bound has been solved (Herrou and Crosson 2013).	α-Proteobacteria	IatP/IatA/IbpA of Caulobacter crescentus IatP (M) (B8H230) IatA (C) (B8H229) IbpA (R) (B8H228)
3.A.1.3: The Polar Amino Acid Uptake Transporter (PAAT) Family
3.A.1.3.1	Histidine; arginine/lysine/ornithine porter	Proteobacteria	HisJ (histidine receptor)-ArgT (arg/lys/orn receptor)-HisMPQ of Salmonella typhimurium HisJ (R) ArgT (R) HisM (M) HisQ (M) HisP (C)
3.A.1.3.2	Glutamine porter	Proteobacteria	GlnHPQ of E. coli GlnH (R) GlnP (M) GlnQ (C)
3.A.1.3.3	Arginine porter	Proteobacteria	ArtI (arginine receptor #1)/ArtJ (arginine receptor #2)-ArtMQP of E. coli ArtP (C) ArtQ (M) ArtM (M) ArtJ (R) ArtI (R)
3.A.1.3.4	Glutamate/aspartate porter	Proteobacteria	GltIJKL of E. coli GltI (R) GltJ (M) GltK (M) GltL (C)
3.A.1.3.5	Octopine porter	Proteobacteria	OccQMPT of Agrobacterium tumefaciens OccT (R) OccQ (M) OccM (M) OccP (C)
3.A.1.3.6	Nopaline porter	Proteobacteria	NocQMPT of Agrobacterium tumefaciens NocT (R) NocQ (M) NocM (M) NocP (C)
3.A.1.3.7	Glutamate/glutamine/aspartate/asparagine porter	Proteobacteria	BztABCD of Rhodobacter capsulatus BztA (R) BztB (M) BztC (M) BztD (CC)
3.A.1.3.8	General L-amino acid porter; transports basic and acidic amino acids preferentially, but also transports aliphatic amino acids (catalyzes both uptake and efflux) (Prell et al. 2009; Hosie et al. 2002 Hosie et al. 2002).	Proteobacteria	AapJQMP of Rhizobium leguminosarum AapJ (R) AapQ (M) AapM (M) AapP (C)
3.A.1.3.9	Glutamate porter	Actinobacteria	GluABCD of Corynebacterium glutamicum GluA (C) GluB (R) GluC (M) GluD (M)
3.A.1.3.10	Cystine/diaminopimelate	Proteobacteria	Cys/Dap porter of E. coli CysX (R) CysY (M) CysZ (C)
3.A.1.3.11	Arginine/ornithine (but not lysine) porter	Proteobacteria	AotJQMP of Pseudomonas aeruginosa AotJ (R) AotQ (M) AotM (M) AotP (C)
3.A.1.3.12	Arginine/lysine/histidine/glutamine porter	Cyanobacteria	BgtAB of Synechocystis PCC6803 BgtA (C) BgtB (R-M)
3.A.1.3.13	Uptake system for L-cystine (Km=2.5 μM), L-cystathionine, L-djenkolate, and S-methyl-L-cysteine (Burguière et al., 2004, Burguière et al., 2005)	Firmicutes	TcyJKLMN (YtmJKLMN) of Bacillus subtilis TcyJ (R) (NP_390816) TcyK (R) (O34852) TcyL (M) (O34315) TcyM (M) (O34931) TcyN (C) (O34900)
3.A.1.3.14	Uptake system for L-cystine (Burguière et al., 2004)	Firmicutes	TcyABC (YckKJI) of Bacillus subtilis TcyA (R) (P42199) TcyB (M) (P42200) TcyC (C) (P39456)
3.A.1.3.15	Putative uptake system for arginine, YqiXYZ (Sekowska et al., 2001)	Bacteria	YqiXYZ of Bacillus subtilis YqiX (R) (P54535) YqiY (M) (P54536) YqiZ (C) (P54537)
3.A.1.3.16	Uptake system for glutamate and aspartate (Leon-Kempis et al., 2006)	Proteobacteria	PEB1 transport system Campylobacter jejuni PEB1a (R) (Q0P9X8) PED1b (M) (A1VZQ3) PEB1c (C) (A3ZI83)
3.A.1.3.17	Basic amino acid uptake transporter, BgtAB (BgtA is shared with NatFGH/BgtA; 3.A.1.3.18; Pernil et al., 2008)	Cyanobacteria	BgtAB of Anabaena sp. PCC7120 BgtA (C) (Q8YPM6) BgtB (R-M) (Q8YSA2)
3.A.1.3.18	Acidic and neutral amino acid uptake transporter NatFGH/BgtA. BgtA is shared with BgtAB (3.A.1.3.17; Pernil et al., 2008)	Cyanobacteria	NatFGH-BgtA of Anabaena sp. PCC7120 BgtA (C) (Q8YPM6) NatF (R) (Q8YPM9) NatG (M) (Q8YPM8) NatH (M) (Q8YPM7)
3.A.1.3.19	Acidic amino acid uptake porter, AatJMQP (Singh and Röhm, 2008)	Bacteria	AatJMQP of Pseudomonas putida AatJ (R) Q88NY2 AatM (M) Q88NY3 AatQ (M) Q88NY4 AatP (C) Q88NY5
3.A.1.3.20	The putative lysine uptake system, LysXY	Bacteria	LysXY of Streptococcus pyogenes LysX (R-M) (Q9A1H0) LysY (C) (Q9A1H1)
3.A.1.3.21	Hydroxy L-proline uptake porter, HprABC (Johnson et al. 2008).	Proteobacteria	HprABC of Pseudomonas aeruginosa HprA (C) (Q9I488) HprB (M) (Q9I487) HprC (R) (Q9I484)
3.A.1.3.22	Amino acid transporter, AatJMQP. Probably transports L-glutamic acid, D-glutamine acid, L-glutamine and N-acetyl L-glutamic acid (Johnson et al. 2008). Very similar to 3.A.1.3.19 of P. putida	Proteobacteria	AatJMQP of Pseudomonas aeruginosa AatJ (R) (Q9I402) AatM (M) (Q9I403) AatQ (M) (Q9I404) AatP (C) (Q9I405)
3.A.1.3.23	Amino acid transporter, PA5152-PA5155. Probably transports numerous amino acids including lysine, arginine, histidine, D-alanine and D-valine (Johnson et al. 2008). Regulated by ArgR.	Proteobacteria	PA5152-PA5144 of Pseudomonas aeruginosa PA5152 (C) (Q9HU32) PA5153 (R) (Q9HU31) PA5154 (M) (Q9HU30) PA5155 (M) (Q9HU29)
3.A.1.4: The Hydrophobic Amino Acid Uptake Transporter (HAAT) Family
3.A.1.4.1	Leucine; leucine/isoleucine/valine porter (also transports phenylalanine and tyrosine; Koyanagi et al., 2004)	Proteobacteria	LivK (leucine-specific receptor)-LivJ (Leu/Ile/Val receptor)-LivHMGF of E. coli LivJ (R) LivK (R) LivH (M) LivM (M) LivG (C) LivF (C)
3.A.1.4.2	Leucine/proline/alanine/serine/glycine (and possibly histidine) porter	Cyanobacteria	NatA-E neutral amino acid porter of Synechocystis sp.PCC6803 NatA (C) NatB (R) NatC (M) NatD (M) NatE (C)
3.A.1.4.3	General L- (and D-)amino acid uptake porter (transports acidic, basic, polar, semipolar and hydrophobic amino acids). The amino and carboxyl groups do not need to be α since γ-aminobutyric acid (GABA) is a substrate. The system may function with additional binding proteins since L-alanine uptake is not dependent on BraC.	Proteobacteria	BraCDEF of Rhizobium leguminosarum BraC (R) BraD (M) BraE (M) BraF (C)
3.A.1.4.4	The high-affinity (<1 μM) urea porter	Cyanobacteria	UrtA-E urea porter of Anabaena sp. PCC7120 UrtA (R) UrtB (M) UrtC (M) UrtD (C) UrtE (C)
3.A.1.4.5	The high affinity urea/thiourea/hydroxyurea porter (Beckers et al., 2004)	Actinobacteria	UrtA-E of Corynebacterium glutamicum UrtA (R) CAF19637 UrtB (M) CAF19636 UrtC (M) CAF19638 UrtD (C) CAF19639 UrtE (C) CAF19640
3.A.1.4.6	The neutral amino acid permease, N-1 (transports pro, phe, leu, gly, ala, ser, gln and his, but gln and his are not transported via NatB) (Picossi et al., 2005)	Cyanobacteria	NatA-E of Anabaena sp. strain PCC7120 NatA (C) BAB73003 NatB (R) BAB73533 NatC (M) BAB73004 NatD (M) BAB73241 NatE (C) BAB74611
3.A.1.4.7	The protocatechuate (3,4-dihydroxybenzoate) uptake porter, PcaMNVWX (Maclean et al., 2011)	δ-Proteobacteria	PcaMNVWX of Sinorhizobium (Ensifer) meliloti PcaM (R) (Q92TN0) PcaN (M) (Q92TN1) PcaV (M) (Q92TN2) PcaW (C) (Q92TN3) PcaX (C) (Q92TN4)
3.A.1.4.8	Branched chain amino acid uptake transporter. Transports alanine (Hoshino and Kose 1990).	Proteobacteria	BraC-G of Pseudomonas aeruginosa BraG (C) (P21630) BraE (C) (P21629) BraE (M) (P21628) BraD (M) (P21627) BraC (R) (P21175)
3.A.1.5: The Peptide/Opine/Nickel Uptake Transporter (PepT) Family
3.A.1.5.1	Oligopeptide porter (also takes up amino glycoside antibiotics such as kanamycin, streptomycin and neomycin as well as cell wall-derived peptides such as murein tripeptide). It transports substrate peptides of 2-5 amino acids with highest affinity for tripeptides. Also transports δ-aminolevulinic acid (ALA). [May be regulated by PTS Enzyme I^Ntr-aspartokinase.] ATP-binding to OppDF may result in donation of peptide to OppBC and simultaneous release of OppA (Doeven et al., 2008).	Proteobacteria	OppABCDF of Salmonella typhimurium OppA (R) OppB (M) OppC (M) OppD (C) OppF (C) MppA (R) (in E. coli)
3.A.1.5.2	Dipeptide porter. Also transports δ-aminolevulinic acid (ALA) and heme (Létoffé et al., 2008).	Firmicutes	DppABCDE of Bacillus subtilis DppA (C) DppB (M) DppC (M) DppD (C) DppE (R)
3.A.1.5.3	Nickel porter. Histidine 416 of NikA is essential for nickel uptake (Cavazza et al., 2011).	Proteobacteria	NikABCDE of E. coli NikA (R) NikB (M) NikC (M) NikD (C) NikE (C)
3.A.1.5.4	Agrocinopine (an opine)/Agrocin 84 (an antibiotic) porter (Kim and Farrand, 1997)	Proteobacteria	AccABCDE of Agrobacterium tumefaciens AccA (R) AccB (C) AccC (C) AccD (M) AccE (M)
3.A.1.5.5	Probable cationic peptide porter (may also take up peptide antibiotics and protamine; implicated in K⁺ homeostasis) [SapD can stimulate the K⁺ uptake activities of TrkH and TrkG (TC #2.A.38.1.1) in the presence of ATP] (Mason et al., 2006)	Bacteria	SapABCDF of Salmonella typhimurium SapA (R) SapB (M) SapC (M) SapD (C) SapF (C)
3.A.1.5.6	The β-glucoside (cellobiose (β-1,4), cellotriose, cellotetraose, cellopentaose, laminaribiose (β-1,3), laminaritriose, sophorose) uptake porter, CbtABCDF	Archaea	The β-glucoside uptake porter of Pyrococcus furiosus, CbtABCDF CbtA (R) CbtB (M) CbtC (M) CbtD (C) CbtF (C)
3.A.1.5.7	The α-galactoside (melibiose, raffinose) uptake porter, AgpABCDF	Bacteria	The α-galactoside uptake porter of Rhizobium meliloti AgpA (R) AgpB (M) (not identified) AgpC (M) (not identified) AgpD (C) (not identified) AgpF (C) (not identified)
3.A.1.5.8	Maltose and maltooligosaccharide porter	Archaea	MalEFGK of Sulfolobus solfataricus MalE (R) MalF (M) MalG (M) MalK (C-C)
3.A.1.5.9	Cellobiose and cellooligosaccharide porter	Archaea	CbtABCDF of Sulfolobus solfataricus CbtA (R) CbtB (M) CbtC (M) CbtD (C) CbtF (C)
3.A.1.5.10	Oligopeptide porter (transports peptides of 4-35) amino acyl residues; di- and tripeptides are not transported; hydrophobic basic peptides are preferred). OppA determines the specificity of the system (Doeven et al., 2004). A large cavity in OppA binds proline-rich peptides preferentially (Berntsson et al., 2009). Two crystal structures of OppA with different nonapeptides show binding in different registers (Berntsson et al., 2011).	Bacteria	OppABCDF of Lactococcus lactis OppA (R) (Q9CEK0) OppB (M) (P0A4N7) OppC (M) (P0A4N9) OppD (C) (Q07733) OppF (C) (P0A2V4)
3.A.1.5.11	Glutathione porter (Suzuki et al., 2005)	Bacteria	YliABCD of E. coli YliA (C-C) (P75796) YliB (R) (P75797) YliC (M) (P75798) YliD (M) (P75799)
3.A.1.5.12	Probable rhamnose oligosaccharide porter. Induced by rhamnose (Conners et al., 2005).	Thermotogae	RtpEFGKL of Thermotoga maritima RtpE (R) (TM1067) Q9X0F7 RtpF (M) (TM1066) Q9X0F6 RtpG (M) (TM1065) Q9X0F5 RtpK (C) (TM1064) Q9X0F4 RtpL (C) (TM1063) Q9X0F3
3.A.1.5.13	Probable xylan oligosaccharide porter (Conners et al., 2005). Induced by xylan and xylose. Regulated by xylose-responsive regulator XylR (Kazanov et al. 2012).	Thermotogae	XloEFGKL of Thermotoga maritima XloE (R) (TM0071) Q9WXS6 XloF (M) (TM0072) Q9WXS7 XloG (M) (TM0073) Q9WXS8 XloK (C) (TM0074) Q9WXS9 XloL (C) (TM0075) Q9WXT5
3.A.1.5.14	Probable cellobiose porter. Induced by barley, glucomannan (Conners et al., 2005)	Thermotogae	CelEFGKL of Thermotoga maritima CelE (R) (TM1223) Q9X0V0 CelF (M) (TM1222) Q9X0U9 CelG (M) (TM1221) Q9X0U8 CelK (C) (TM1220) Q9X0U7 CelL (C) (TM1219) Q9X0U6
3.A.1.5.15	Probable mannose/mannoside porter. Induced by beta-mannan (Conners et al., 2005). Regulated by mannose-responsive regulator manR (Kazanov et al., 2012).	Thermotogae	MtpEFGKL of Thermotoga maritima MtpE (R) (TM1746) Q9X268 MtpF (M) (TM1747) Q9X269 MtpG (M) (TM1748) Q9X270 MtpK (C) (TM1749) Q9X271 MtpL (C) (TM1750) Q9X272
3.A.1.5.16	β-glucoside porter (Conners et al., 2005). Binds cellobiose, laminaribiose (Nanavati et al. 2006). Regulated by cellobiose-responsive repressor BglR (Kazanov et al. 2012).	Thermotogae	BglpEFGKL of Thermotoga maritima BglE (R) (TM0031) Q9WXN8 BglF (M) (TM0030) Q9WXN7 BglG (M) (TM0029) Q9WXN6 BglK (C) (TM0028) Q9WXN5 BglL (C) (TM0027) Q9WXN4
3.A.1.5.17	The proline betaine uptake porter (Alloing et al., 2006)	Proteobacteria	PrbABCD of Sinorhizobium meliloti PrbA (R) (Q92NF1) PrbB (M) (Q92NF0) PrbC (M) (Q92NE9) PrbD (C-C) (Q92NE8)
3.A.1.5.18	The oligopeptide transporter OppA1-5, B1, C1, DF (functions with five binding proteins of differing induction properties and peptide specificities; OppA1-3 are chromosomally encoded; OppA4 and 5 are plasmid encoded.) (Medrano et al., 2007)	Bacteria	OppA1-5,B1,C1,D,F of Borrelia burgdorferi OppA1 (R): O51307 OppA2 (R): O54584 OppA3 (R): O51308 OppA4 (R): O31315 OppA5 (R): O50927 OppB1 (M): O31307 OppC1 (M): O51310 OppD (C): O31309 OppF (C): O31310
3.A.1.5.19	The major oligopeptide uptake porter, Opp-3 (of four paralogues, this is the only one that mediates nitrogen nutrition (Hiron et al., 2007).	Bacteria	Opp-3 of Staphylococcus aureus OppB (M) = (Q2FZR7) OppC (M) = (Q2FZR6) OppD (C) = (Q2FZR5) OppF (C) = (Q2FZR4) OppA (R) = (Q2FZR3)
3.A.1.5.20	5-6 amino acyl oligopeptide transporter AppA-F (Koide and Hoch, 1994).	Bacteria	AppABCDF of Bacillus subtilis AppA(R) (P42061) AppB(M) (P42062) AppC(M) (P42063) AppD(C) (P42064) AppF(C) (P42065)
3.A.1.5.21	The Microcin C uptake porter, YejABEF (other substrate unknown) (Novikova et al., 2007)	Bacteria	YejABEF of E. coli: YejA (R) (P33913) YejB (M) (P0AFU1) YejE (M) (P33915) YejF (C-C) (P33916)
3.A.1.5.22	The peptide transporter OppA,B,C,D,F (influences biofilm formation; Lee et al., 2004). Similar to 3.A.1.5.1, OppA is similar to the Vibrio furnissii OppA that provides several functions: hemolysis, antibiotic resistance, and virulence (Wu et al., 2007).	Bacteria	OppABCDF of Vibrio fluvialis: OppA (R) (Q5V9S2) OppB (M) (Q5V9S1) OppC (M) (Q5V9S0) OppD (C) (Q5V9R9) OppF (C) (Q5V9R8)
3.A.1.5.23	The Ethylene diamine tetraacetate (EDTA) uptake porter, EppABCD (Zhang et al., 2007).	Bacteria	EppABCD of EDTA-degrading bacterium BNC1: EppA (R) (Q9F9T7) EppB (M) (Q9F9T6) EppC (M) (Q9F9T5) EppD (C-C) (Q9F9T4)
3.A.1.5.24	The antimicrobial peptide (protamine, melittin, polymyxin B, human defensin (HBD)-1 and HBD-2 exporter, YejABEF (Eswarappa et al., 2008). Prefers N-formyl methionine peptides, such as Microcin C (of prokaryotic origin) to non formylated peptides (of eukaryotic origin) (Novikova et al., 2007).	Proteobacteria	YejABEF of Salmonella enterica YejA (R) (Q8ZNK0) YejB (M) (Q7CQ74) YejE (M) (Q8ZNJ9) YejF (C-C) (Q8ZNJ8)
3.A.1.5.25	The ABC peptide/signalling peptide transporter. OptA binds peptides of 3-6 aas; OptS binds dipeptides. OptB,C,D are most similar to 3.A.1.5.19.	Gram-positive bacteria	The OptASBCDF transport system of Lactococcus lactis OptS (R) (Q64K09) OptA (R) (Q9CIL2) OptB (M) (Q9CILI) OptC (M) (Q9CIL0) OptD (C) (Q9CIK9) OptF (C) (Q9CIK8)
3.A.1.5.26	The glutamine transporter, OppA (Dasgupta et al., 2010). OppA binds glutathione and the nanopeptide, bradykinin. Also regulates cytokine release, apoptosis and the innate immune response of macrophages infected with M. tuberculosis (Dasgupta et al., 2010).	Bacteria	Peptide transporter of Mycobacterium tuberculosis OppA (R) (P66771) OppD (C) (P63395) OppC (M) (P66964) OppB (M) (P66966)
3.A.1.5.27	The glutathione uptake porter, DppBCDF with the glutathione binding protein, DppA (GbpA; HbpA). Takes up reduced (GSH) and oxidized (GSSG) but not bulky glutathione S conjugates or glutathione derivatives with C-terminal modifications (Vergauwen et al., 2010).	Bacteria	DppABCDF of Haemophilus influenzae DppA (R) (P33950) DppB (M) (P45096) DppC (M) (P51000) DppD (C) (P45095) DppF (C) (P45094)
3.A.1.5.28	The Nickel (Ni²⁺) uptake porter, NikZYXWV (Howlett et al., 2012).	Bacteria	NikZYXWV of Campylobacter jejuni NikZ (R) (Q0P844) NikY (M) (Q0P845) NikX (M) (Q0P846) NikW (C) (Q0P847) NikV (C) (Q0P848)
3.A.1.5.29	Probable xylan oligosaccharide porter (Conners et al. 2005). Induced by cylan and xylose. Regulated by xylose-responsive regulator XylR (Kazanov et al. 2012).	Thermotogae	XtpELKGF of Thermotoga maritima XtpE (R) (TM0056) (Q9WXR2) XtpL (C) (TM0057) (Q9WXR3) XtpK (C) (TM0058) (Q9WXR4) XtpG (M) (TM0059) (Q9WXR5) XtpF (M) (TM0060) (Q9WXR6)
3.A.1.5.30	Putative fucose-glucose oligosaccharide porter. Binds xyloglucan hepta-, octa-, nonasaccharides with beta-1,4- tetraglucosyl backbones (Conners et al., 2005)	Thermotogae	GloEFGKL of Thermotoga maritima GloE (R) (TM0300) (Q9WYD6) GloF (M) (TM0301) (Q9WYD7) GloG (M) (TM0302) (Q9WYD8) GloK (C) (TM0303) (Q9WYD9) GloL (C) (TM0304) (Q9WYE0)
3.A.1.5.31	Predicted galactoside porter. Induced by lactose (Conners et al., 2005)	Thermotogae	LtpE (R) (TM1199) Q9X0S6 LtpF (M) (TM1198) Q9X0S5 LtpG (M) (TM1197) Q9X0S4 LtpK (C) (TM1196) Q9X0S3 LtpL (C) (TM1194) Q9S5X6
3.A.1.6: The Sulfate/Tungstate Uptake Transporter (SulT) Family
3.A.1.6.1	Sulfate/thiosulfate porter	Proteobacteria	Sbp (sulfate receptor)-CysP (thiosulfate receptor)-CysTWA of E. coli Sbp (R) CysP (R) CysT (M) CysW (M) CysA (C)
3.A.1.6.2	Tungstate porter. (TupA, the receptor, exhibits an extremely high affinity for tungstate (K_d <1 nM) and discriminates between tungstate and molybdate (Andreesen and Makdessi, 2007))	Firmicutes	TupABC of Eubacterium acidaminophilum TupA (R) TupB (M) TupC (C)
3.A.1.6.3	Sulfate porter	Actinobacteria	CysAWT SubI-sulfate porter of Mycobacterium tuberculosis CysA (C) CysW (M) CysT (M) SubI (R)
3.A.1.6.4	Vanadate porter (Pratte and Thiel, 2006) (most similar to TupABC (3.A.1.6.2))	Cyanobacteria	VupABC of Anabaena variabilis ATCC29413 VupA (R) (ABA23645) VupB (M) (ABA23644) VupC (C) (ABA23643)
3.A.1.6.5	Tungsten (K_M=20pM)/molybdate (K_M=10nM) porter (Bevers et al., 2006)	Euryarchaeota	WtpABC of Pyrococcus furiosus WtpA (R) (Q8U4K5) WtpB (M) (Q8U4K4) WtpC (C) (Q8U4K3)
3.A.1.6.6	The Molybdate/Tungstate Transporter, ModA-C (Zhang and Gladyshev, 2008).	Archaeon	ModABC of Pyrobaculum calidifontis ModA (R) (A3MW02) ModB (M) (A3MW01) ModC (C) (A3MW00)
3.A.1.6.7	The chloroplast sulfate transporter, SulP/SulP2/Sabc/Sbp (Melis & Chen et al., 2005).	Algae	Chloroplast sulfate uptake permease of Chlamydomonas reinhardtii SulP (M) (Q8RVC7) SulP2 (M) (Q6QJE2) Sabc (C) (Q6QJE1) Sbp (R) (Q6QJE0)
3.A.1.6.8	Molybdate/tungstate transport system, ModABC (WtpABC) (ModA binds to ModBC with high affinity (0.11%u03BCM) and dissociates slowly; the complex is destabilized by nucleotide and substrate binding (Vigonsky et al. 2013).	Archaea	ModABC of Archeoglobus fulgidus ModB (M; 12 TMSs; type I fold) (O30143) ModC (C) (O30144) ModA (R) (O30142)
3.A.1.7: The Phosphate Uptake Transporter (PhoT) Family
3.A.1.7.1	Phosphate porter	Proteobacteria	PhoS (phosphate receptor)-PstABC of E. coli PhoS (R) PstA (M) PstC (M) PstB (C)
3.A.1.7.2	Phosphate transporter, PstSCAB (Gebhard and Cook, 2007).	Actinobacteria	PstSCAB of Mycobacterium smegmatis PstS (R) (Q7WTY8) PstC (M) (Q7WTY7) PstA (M) (Q7WTY6) PstB (C) (P0C560)
3.A.1.7.3	High-affinity phosphate-specific permease, PstAB/PhoS. The 3-d structure of PhoS = (PBP) = PfluDING) has been solved at high resolution by x-ray crystallography (Ahn et al. 2007) with phosphate bound (4F1U and 4F1V; 0.95Å resolution) and with arsenate bound (4F18 and 4F19; 0.88Å resolution) (Elias et al. 2012). Phosphate binds with 500-fold higher affinity than arsenate due to a dense and rigid network of ion-dipole interactions (Elias et al. 2012). The PBP from Halomonas sp. GFAJ-1 has a phosphate affinity 5000-fold higher than that of arsenate (Elias et al. 2012).	Bacteria	PstAB/PhoS of Pseudomonas fluorescens PstA (C) (C3KCB5) PstB (M) (C3KCB6) PstC (PBP) (R) (D0VWY2)
3.A.1.8: The Molybdate Uptake Transporter (MolT) Family
3.A.1.8.1	Molybdate porter	Proteobacteria	ModABC of E. coli ModA (R) ModB (M) ModC (C)
3.A.1.8.2	The molybdate/tungstate ABC transporter, ModABC. The trans-inhibited 3-d structure of ModABC, is available (3D31.A and 3D31.B)(Gerber et al., 2008)	Archaea	ModABC of Methanosarcina acetivorans ModA (Q8TTV0) ModB (M) (Q8TJ86) ModC (C) (Q8TTV2)
3.A.1.9: The Phosphonate Uptake Transporter (PhnT) Family
3.A.1.9.1	Phosphonate/organophosphate ester porter (broad specificity). Reviewed by Hinz & Tampé (2012).	Proteobacteria	PhnCDE of E. coli PhnC (C) PhnD (R) PhnE (M)
3.A.1.9.2	Phosphonate/phosphate porter, PhnDCE (Gebhard and Cook, 2007)	Bacteria	PhnDCE of Mycobacterium smegmatis PhnC (C) (A0QQ70) PhnD (R) (A0QQ71) PhnE (M) (A0QQ68)
3.A.1.10: The Ferric Iron Uptake Transporter (FeT) Family
3.A.1.10.1	Ferric iron (Fe³⁺) porter	Proteobacteria	SfuABC of Serratia marcescens SfuA (R) SfuB (M) SfuC (C)
3.A.1.10.2	Ferric iron (Fe³⁺) porter	Cyanobacteria	Fut A1A2BC of SynechocystisPCC6803 FutA1 (R) FutA2 (R) FutB (M) FutC (C)
3.A.1.10.3	Ferric iron (Fe³⁺) porter (selective for trivalent cations, Fe³⁺, Ga³⁺ and Al³⁺) (Anderson et al., 2004)	Proteobacteria	FbpABC (HitABC) of Haemophilus influenzae FbpA (R) (AAC21773) FbpB (M) (AAC21774) FbpC (C) (AAC21775)
3.A.1.10.4	The Fe-hydroxamate-type siderophore uptake porter (transports Fe⁺³ bound to ferrioxamine, ferrichrome or pyoverdine siderophores) (Vajrala et al., 2010).	Bacteria	NitABC of Nitrosomonas europaea NitA (R) (Q82VN7) NitB (M) (Q82VN6) NitC (C) (Q82VN5)
3.A.1.11: The Polyamine/Opine/Phosphonate Uptake Transporter (POPT) Family
3.A.1.11.1	Polyamine (putrescine/spermidine) porter	Proteobacteria	PotABCD of E. coli PotA (C) PotB (M) PotC (M) PotD (R)
3.A.1.11.2	Putrescine porter	Proteobacteria	PotGHIF of E. coli PotG (C) PotH (M) PotI (M) PotF (R)
3.A.1.11.3	Mannopine porter	Proteobacteria	MotABCD of Agrobacterium tumefaciens plasmid pTi15955 MotA (R) MotB (C) MotC (M) MotD (M)
3.A.1.11.4	Chrysopine porter	Proteobacteria	ChtGHIJK of Agrobacterium tumefaciens ChtG (C) ChtH (R) ChtI (R) ChtJ (M) ChtK (M)
3.A.1.11.5	2-aminoethyl phosphonate porter	Proteobacteria	PhnSTUV of Salmonella typhimurium PhnS (R) PhnT (C) PhnU (M) PhnV (M)
3.A.1.11.6	The γ-aminobutyrate (GABA) uptake system, GtsABCD (White et al., 2009).	Bacteria	GtsABCD of Rhizobium leguminosarum GtsA (R) (Q1M7Q4) GtsB (M) (Q1M7Q3) GtsC (M) (Q1M7Q2) GtsD (C) (Q1M7Q1)
3.A.1.12: The Quaternary Amine Uptake Transporter (QAT) Family (Similar to 3.A.1.16 and 3.A.1.17)
3.A.1.12.1	Glycine betaine/proline porter, ProU or ProVWX (also transports proline betaine, carnitine, dimethyl proline, homobetaine, γ-butyrobetaine and choline with low affinity). Contributes to the regulation of cell volume is response to osmolarity. A reconsituted system shows osmotic strength-gating (Gul and Poolman 2012).	Proteobacteria	ProVWX of E. coli ProW (M) ProX (R) ProV (C)
3.A.1.12.2	Glycine betaine porter (also transports dimethylsulfonioacetate and dimethylsulfoniopropionate)	Firmicutes	OpuAA, AB, AC of Bacillus subtilis OpuAA (C) OpuAB (M) OpuAC (R)
3.A.1.12.3	Choline porter	Firmicutes	OpuBA, BB, BC, BD of Bacillus subtilis OpuBA (C) OpuBB (M) OpuBC (R) OpuBD (M)
3.A.1.12.4	Uptake system for choline, L-carnitine, D-carnitine, glycine betaine, proline betaine, crotonobetaine, γ-butyrobetaine, dimethylsulfonioacetate, dimethylsulfoniopropionate, ectoine and choline-O-sulfate	Firmicutes	OpuCA, CB, CC, CD of Bacillus subtilis OpuCA (C) OpuCB (M) OpuCC (R) OpuCD (M)
3.A.1.12.5	Uptake system for glycine-betaine (high affinity) and proline (low affinity) (OpuAA-OpuABC) or BusAA-ABC of Lactococcus lactis). BusAA, the ATPase subunit, has a C-terminal tandem cystathionine β-synthase (CBS) domain which is the cytoplasmic K⁺ sensor for osmotic stress (osmotic strength)while the BusABC subunit has the membrane and receptor domains fused to each other (Biemans-Oldehinkel et al., 2006; Mahmood et al., 2006; Gul et al. 2012). An N-terminal amphipathic α-helix of OpuA is necessary for high activity but is not critical for biogenesis or the ionic regulation of transport (Gul et al., 2012).	Firmicutes	BusAA-AB of Lactococcus lactis BusAA (C-CBS) BusAB (M-R)
3.A.1.12.6	Uptake system for hisitidine, proline, proline-betaine and glycine-betaine	Proteobacteria	HutXWV of Sinorhizobium meliloti HutX (R) HutW (M) HutV (C)
3.A.1.12.7	High affinity (3 μM) choline-specific uptake system (Dupont et al., 2004)	Proteobacteria	ChoXWV of Sinorhizobium meliloti ChoX (R) (AAM00244) ChoW (M) (AAM00245) ChoV (C) (AAM00246)
3.A.1.12.8	A proline/glycine betaine uptake system. Also reported to be a bile exclusion system that exports oxgall and other bile compounds, BilEA/EB or OpuBA/BB (required for normal virulence) (R.D. Sleator et al., 2005).	Bacteria	OpuBA/BB or BilEA/EB of Listeria monocytogenes OpuBA (C) (Q93A35) OpuBB (M-R) (Q93A34)
3.A.1.12.9	The salt-induced glycine betaine OtaABC transporter (Schmidt et al., 2007)	Archaea	OtaABC of Methanosarcina mazei Go1 OtaA (C) Q8U4S5 OtaB (M) Q8U4S4 OtaC (R) Q8U4S3
3.A.1.12.10	The OpuC transporter selective for glycine betaine > choline, acetylcholine, carnitine and proline betaine (contains tandem cystathionine-β-synthase (CBS) domains in the ABC component of OpuC that are required for osmoregulatory function (Chen and Beattie, 2007)).	Proteobacteria	OpuCA, CB, CC of Pseudomonas syringae OpuCC (R) (Q87WH3) OpuCB (M) (Q87WH4) OpuCA (C) (Q87WH5)
3.A.1.12.11	The glycine betaine uptake porter, GbpABCD (Saum et al., 2009).	Archaea	GbpABCD of Methanosarcina mazei GbpA (R) (Q8Q040) GbpB (M) (Q8Q043) GbpC (M) (Q9Q042) GbpD (C) (Q8Q041)
3.A.1.12.12	The CbcWV/CbcX (choline)/CaiX (carnitine)/BetX (betaine) transporter with 3 binding receptors for distinct quaternary ammonium compounds. Only the ligand-bound receptor binds to the transporter with high affinity (Chen et al., 2010; Thomas et al., 2010).	Bacteria	CbcWV/CbcX/CaiX/BetX of Pseudomonas aeruginosa CbcW (M) (Q9HTI7) CbcV (C) (Q9HTI8) CbcX (R) (Q9HTI6) CaiX (R) (Q9HTH6) BetX (R) (Q9HZ04)
3.A.1.12.13	High affinity (2mμM) choline uptake porter. The choline binding receptor exhibits a venus fly trap mechanism of substrate binding. (ChoX binds acetyl choline and betaine with low affinity (80μM and 470μM, respectively) (Aktas et al., 2011) (most similar to 3.A.1.12.7)	Bacteria	ChoVWX of Agrobacterium tumefaciens ChoX (R) (Q7CXG0) ChoW (M) (Q7CXG1) ChoV (C) (A9CI32)
3.A.1.12.14	OsmU (OsmVWXY) transporter for glycine betaine and choline-O-sulfate uptake. Induced by osmotic stress (0.3M NaCl) (Frossard et al., 2012).	Proteobacteria	OsmU or OsmVWXY of Salmonella enterica OsmV (STM1491) (C) (Q8ZPK4) OsmW (STM1492) (M) (Q8ZPK3) OsmX (STM1493) (R) (Q8ZPK2) OsmY (STM1494) (M) (Q8ZPK1)
3.A.1.13: The Vitamin B₁₂ Uptake Transporter (B₁₂T) Family (Similar to 3.A.1.14)
3.A.1.13.1	Vitamin B₁₂ porter. The 3-D structure of BtuCDF has been solved to 2.6Å (Hvorup et al., 2007). The conformational transition pathways of BtuCD has been revealed by targeted molecular dynamics simulation (Weng et al., 2012). Asymmetric states of BtuCD are not discriminated by its cognate substrate binding protein BtuF (Korkhov et al., 2012).	Proteobacteria	BtuCDF of E. coli BtuC (M) BtuD (C) BtuF (R)
3.A.1.14: The Iron Chelate Uptake Transporter (FeCT) Family (Similar to 3.A.1.13 and 3.A.1.15)
3.A.1.14.1	Iron (Fe³⁺) or ferric-dicitrate porter (Braun and Herrmann, 2007)	Proteobacteria	FecBCDE of E. coli FecB (R) FecC (M) FecD (M) FecE (C)
3.A.1.14.2	Iron (Fe³⁺)-enterobactin porter	Proteobacteria	FepBCDG of E. coli FepB (R) (C8U2V6) FepC (C) (P23878) FepD (M) (P23876) FepG (M) (P23877)
3.A.1.14.3	Iron (Fe³⁺)-hydroxamate (ferrichrome, coprogen, aerobactin, ferrioxamine B, schizakinen, rhodotorulic acid) porter, albomycin porter	Proteobacteria	FhuBCD of E. coli FhuB (M-M; 20 TMSs; 10+10) FhuC (C) FhuD (R)
3.A.1.14.4	Iron-chrysobactine porter	Proteobacteria	CbrABCD of Erwinia chrysanthemi CbrA (R) CbrB (M) CbrC (M) CbrD (C)
3.A.1.14.5	Heme (hemin) uptake porter. The receptor, HmuT, binds two parallel stacked heme molecules, and two are transported per reaction cycle (Mattle et al., 2010).	Proteobacteria	HmuTUV of Yersinia pestis HmuT (R) (Q56991) HmuU (M) (Q56992) HmuV (C) (Q56993)
3.A.1.14.6	The iron-vibriobactin/enterobactin uptake porter	Proteobacteria	ViuPDGC of Vibrio cholerae ViuP (R) ViuD (M) ViuG (M) ViuC (C)
3.A.1.14.7	Iron (Fe³⁺)-hydroxamate porter (transports Fe³⁺-ferrichrome and Fe³⁺-ferrioxamine B with FhuD1, and these compounds plus aerobactin and coprogen with FhuD2).	Firmicutes	FhuBCD1D2 of Staphylococcus aureus FhuB (M) FhuC (C) FhuD1 (R) FhuD2 (R)
3.A.1.14.8	The iron-vibrioferrin uptake porter (Tanabe et al., 2003)	Proteobacteria	PvuBCDE of Vibrio parahaemolyticus PvuB (R) (BAC16540) PvuC (M) (BAC16541) PvuD (M) (BAC16542) PvuE (C) (BAC16543)
3.A.1.14.9	The Corrinoid porter, BtuCDE (Woodson et al., 2005)	Archaea	BtuCDE of Halobacterium sp. strain NRC-1 BtuC (M) (AAG19698) BtuD (C) (NP_444218) BtuE (R) (AAG19697)
3.A.1.14.10	The heme porter, Shp/SiaABC (HtsABC). Shp is a cell surface heme binding protein that transfers the heme directly to HstA (Nygaard et al., 2006). The crystal structure of the heme binding domain of Shp has been solved (Aranda et al., 2007). HtsABC is required for the uptake of staphyloferrin A (Beasley et al. 2009). The Shr cell surface heme receptor may feed iron-heme to Shp in preparation for uptake (Ouattara et al., 2010).	Bacteria	Shp/HtsABC of Streptococcus pyogenes Shp (R₁) (291 aas; Q1J548) HtsA (R₂) (294 aas; Q99YA2) HtsB (M) (340 aas; Q99YA3) HtsC (C) (278 aas; Q99YA4)
3.A.1.14.11	The molybdate/tungstate ABC transporter, MolABC.� For MolC; HI1470(C)/MolB; HI1471(M), the 3D structure is known at 2.4 � resolution; Pinkett et al., 2007).� MolA binds to MolBC with low affinity (50 - 100 %u03BCM), forming a transient complex that is stabilitzed by ligand binding (Vigonsky et al. 2013).	Bacteria	MolABC of Haemophilus influenzae MolC; HI1470 (C) (Q57399) MolB; HI1471 (M; 10 TMSs; type II fold) (Q57130) MolA; HI1472 (R) (E3GUW2)
3.A.1.14.12	Desferrioxamine B uptake porter, DesABC (Barona-Gomez et al., 2006)	Bacteria	DesABC of Streptomyces coelicolor DesA (R) (CAB76300) DesB (M-M; 18 TMSs; 9+9 TMSs) (CAB76299) DesC (C) (CAB76301)
3.A.1.14.13	Coelichelin uptake porter, CchCDEF (Barona-Gomez et al., 2006)	Bacteria	CchCDEF of Streptomyces coelicolor CchC (M) (CAB53327) CchD (M) (CAB53326) CchE (C) (CAB53325) CchF (R) (CAB53324)
3.A.1.14.14	The Fe³⁺ uptake porter; SiuABDG (Montañez et al., 2005)	Bacteria	SiuABDG (FtsABCD) of Streptococcus pyogenes SiuA; FtsA (C) (Q9A197) SiuD; FtsB (R) (Q9A199) SiuB; FtsC (M) (Q9A198) SiuG; FtsD (M) (Q06A41)
3.A.1.14.15	Uptake transporter for the catecholic trilactone (2, 3-dihydroxybenzoate-glycine-threonine)₃ siderophore bacillibactin (for ferric iron scavenging), FeuABC (Gaballa and Helmann, 2007; Miethke et al., 2006).	Bacteria	FeuABC of Bacillus subtilis FeuA (R) (P40409) FeuB (M) (P40410) FeuC (M) (P40411)
3.A.1.14.16	The heme-specific uptake porter, HemTUV (Létoffé et al., 2008).	Bacteria	HemTUV of Serratia proteamaculans HemT (R) - (A8GDS8) HemU (M) - (A8GDS7) HemV (C) - (A8GDS6)
3.A.1.14.17	Heme acquisition ABC uptake transporter, IsdDEF (Liu et al., 2008)	Firmicutes	IsdDEF of Staphylococcus aureus IsdD (?) (358aas, 2TMSs) (Q5HGV2) IsdE (R) (295aas, 1TMS) (Q7A652) IsdF (M) (273aas; 8TMSs) (Q7A651)
3.A.1.14.18	The heme uptake porter, ShuTUV (Burkhard and Wilks, 2008). Transports a single heme per reaction cycle (Mattle et al., 2010). (3-d structure of ShuT is known (2RG7).	Bacteria	ShuTUV of Shigella dysenteriae ShuT(R) (Q32AX9) ShuU(M) (Q32AY2) ShuV(C) (Q32AY3)
3.A.1.14.19	Heme uptake porter, HugBCD (Villarreal et al., 2008); also called HmuTUV.	Bacteria	HugBCD of Plesiomonas shigelloides HugB (R) (Q93SS3) HugC (M) (Q93SS2) HugD (C) (Q93SS1)
3.A.1.14.20	Heme-iron (hemin) utilization transporter BhuTUV ( Brickman et al., 2006; Vanderpool and Armstrong, 2004).	Gram-negative bacteria	BhuTUV of Bordetella pertussis BhuT (R) (Q7VSQ6) BhuU (M) (Q7W024) BhuV (C) (Q7W025)
3.A.1.14.21	The heme uptake porter, PhuTUV (transports one heme per reaction cycle) (Mattle et al., 2010).	Bacteria	PhuTUV of Pseudomonas aeruginosa PhuT (R) (Q9HV90) PhuU (M) (O68878) PhuV (C) (O68877)
3.A.1.15: The Manganese/Zinc/Iron Chelate Uptake Transporter (MZT) Family (Similar to 3.A.1.12, 3.A.1.14 and 3.A.1.16)
3.A.1.15.1	Manganese (Mn²⁺) porter	Cyanobacteria	MntABC of Synechocystis 6803 MntA (C) MntB (M) MntC (R)
3.A.1.15.2	Manganese (Mn²⁺) and zinc (Zn²⁺) porter	Firmicutes	ScaABC of Streptococcus gordonii ScaA (R) ScaB (M) ScaC (C)
3.A.1.15.3	Zinc (Zn²⁺) porter	Firmicutes	AdcABC of Streptococcus pneumoniae AdcA (R) AdcB (M) AdcC (C)
3.A.1.15.4	Iron and manganese porter	Proteobacteria	YfeABCD of Yersinia pestis YfeA (R) YfeB (C) YfeC (M) YfeD (M)
3.A.1.15.5	Zinc (Zn²⁺) porter (required for Zn²⁺ homeostasis and virulence of Salmonella enterica; Ammendola et al., 2007).	Proteobacteria	ZnuABC (YebLMI) of E. coli ZnuA (R) ZnuC (C) ZnuB (M)
3.A.1.15.6	Iron (Fe²⁺)/Zinc (Zn²⁺)/Copper (Cu²⁺) porter	Firmicutes	MtsABC of Streptococcus pyogenes MtsA (R) MtsB (C) MtsC (M)
3.A.1.15.7	Manganese (Mn²⁺) (Km=0.1 μM) and iron (Fe²⁺) (5 μM) porter (inhibited by Cd²⁺ > Co²⁺ > Ni²⁺, Cu²⁺) (most similar to YfeABCD of Yersinia pestis (TC #3.A.1.15.4)). Important for virulence in Salmonella (Karlinsey et al., 2010).	Proteobacteria	SitABCD of Salmonella typhimurium SitA (R) SitB (C) SitC (M) SitD (M)
3.A.1.15.8	Manganese (Mn²⁺), zinc (Zn²⁺) and possibly iron (Fe²⁺) porter (Hazlett et al., 2003)	Spirochaetes	TroABCD of Treponema pallidum TroA (R) P96116 TroB (C) P96117 TroC (M) P96118 TroC (M) P96119
3.A.1.15.9	Manganese (Mn²⁺) and Iron (Fe²⁺) porter, SitABCD (Davies and Walker, 2007)	Bacteria	Sit ABCD of Sinorhizobium meliloti SitA (R) - (Q92LL5) SitB (M) - (Q92LL4) SitC (C) - (Q92LL3) SitD (M) - (Q92LL2)
3.A.1.15.10	The Mn²⁺/Zn²⁺ transporter MntABC (K_B of Mn²⁺ and Zn²⁺ is 0.1μM which bind with equal affinity to the same site (Lim et al., 2008)	Bacteria	MntABC of Neisseria meningitidis: MntA (C) (A1IQK5) MntB (M) (A1IQK4) MntC (R) (Q5FA63)
3.A.1.15.11	The zinc uptake porter, YcdHI-YceA (Gaballa et al., 2002).	Firmicutes	YcdHI-YceA of Bacillus subtilis AdcA (YcdH) (R) (O34966) AdcC (YcdI) (C) (O34946) AdcB (YceA) (M) (O34610)
3.A.1.16: The Nitrate/Nitrite/Cyanate Uptake Transporter (NitT) Family (Similar to 3.A.1.12 and 3.A.1.17)
3.A.1.16.1	Nitrate/nitrite porter	Cyanobacteria	NrtABCD of Synechococcus sp. (PCC 7942) NrtA (R) NrtB (M) NrtC (C) NrtD (C)
3.A.1.16.2	Bispecific cyanate/nitrite transporter (functions in both cyanate and nitrite assimilation; Maeda and Omata, 2009).	Cyanobacteria	CynABD of Synechococcus PCC7942 CynA (R) CynB (M) CynD (C)
3.A.1.16.3	Bicarbonate porter (activated by low [CO₂] mediated by CmpR; (Nishimura et al., 2008))	Cyanobacteria	CmpABCD of Synechococcus sp. CmpA (R) CmpB (M) CmpC (C) CmpD (C)
3.A.1.16.4	Nitrate uptake system, NrtABCD (Frías et al., 1997)	Cyanobacteria	NrtABCD of Anabaena (Nostoc) sp. PCC 7120 NrtA (R) (Q44292) NrtB (M) (Q8YRV7) NrtC (C-R) (Q8YRV8) NrtD (C) (Q8YZ25)
3.A.1.17: The Taurine Uptake Transporter (TauT) Family (Similar to 3.A.1.12 and 3.A.1.16)
3.A.1.17.1	Taurine (2-aminoethane sulfonate) porter	Proteobacteria	TauABC of E. coli TauA (R) TauB (C) TauC (M)
3.A.1.17.2	Aromatic sulfonate porter	Proteobacteria	SsuABC of Pseudomonas putida SsuA (R) SsuB (C) SsuC (M)
3.A.1.17.3	Putative hydroxymethylpyrimidine transport system, ThiXYZ (Rodionov et al., 2002). Regulated by TPP (thiamin) riboswitch. Potentially takes up a pyrimidine moiety of thiamin.	Bacteria	ThiXYZ of Haemophilus influenzae ThiZ (C) (P44656) ThiX (M) (Q57306) ThiY (R) (P44658)
3.A.1.17.4	The taurine uptake system, TauABC (Krejcík et al., 2008).	Proteobacteria	TauABC of Neptuniibacter caesariensis TauA (R) (Q2BM68) TauB (C) (Q2BM69) TauC (M) (Q2BM70)
3.A.1.17.5	The phthalate uptake system, OphFGH (Chang et al. 2009).	Bacteria	OphFGH of Burkholderia capacia OphF (R) (C0LZR7) OphG (M) (C0LZR8) OphH (C) (C0LZR9)
3.A.1.17.6	Putative hydroxymethylpyrimidine transport system, ThiXYZ (Rodionov et al., 2002). Regulated by TPP (thiamin) riboswitch. Potentially takes up a pyrimidine moiety of thiamin. ThiY is homologous to the yeast THI5 HMP-P synthase (P43534) (Bale et al., 2010).	Actinobacteria, Proteobacteria	ThiXYZ of Pasteurella multocida ThiX (M) (Q9CLG9) ThiY (R) (Q9CLH1) ThiZ (C) (Q9CLG8)
3.A.1.17.7	Putative riboflavin transport system, RibXY. Regulated by FMN riboswitch (Vitreschak et al. 2002)	Chloroflexi	RibXY of Roseiflexus castenholziiRibX (M) (A7NLS3)RibY (R) (A7NLS2)
3.A.1.17.8	Putative thiamine transport system, ThiXYZ (Rodionov et al., 2002). Regulated by TPP (thiamin) riboswitch.	Chloroflexi	ThiXYZ of Roseiflexus castenholziThiX (M) (A7NH43)ThiY (R) (A7NH44)ThiZ (C) (A7NH45)
3.A.1.18: The Cobalt Uptake Transporter (CoT) Family
3.A.1.18.1	Cobalt (Co²⁺) porter (Rodionov et al., 2006). CbiMN is a bipartite S-subunit with 8 TMSs (Siche et al. 2010).	Proteobacteria	CbiMNOQ of Salmonella typhimurium CbiM (M) (Q05594) CbiN (Essential auxillary subunit) (Q05595) CbiO (C) (Q05596) CbiQ (M) (Q05598)
3.A.1.19: The Thiamin Uptake Transporter (ThiT) Family (Most similar to 3.A.1.10, 3.A.1.6 and 3.A.1.8 in that order)
3.A.1.19.1	Thiamin, thiamin monophosphate and thiamin pyrophosphate porter. The 2.25 � structure of ThiB (TbpA) has been solved (Soriano et al., 2008).	Proteobacteria	ThiBPQ of Salmonella typhimurium (functionally characterized and partially sequenced) and E. coli (fully sequenced but not functionally characterized) ThiB; TbpA (R) ThiP; YabK (M) ThiQ; YabJ (C)
3.A.1.19.2	The thiamine pyrophosphate (TPP) uptake porter (Bian et al., 2011).	Bacteria	TPP transporter of Treponena denticola TDE0143/TDE0144/TDE0145 TDE0143 (R) (Q73RE6) TDE0144 (M) (Q73RE5) TDE0145 (C) (Q73RE4)
3.A.1.19.3	ABC transporter of unknown function. The three genes encoding this system are adjacent to a gene homologous to a mycothiol maleylpyruvate isomerase.	Actinobacteria	ABC transporter of Streptomyces hygroscopicus Periplasmic binding protein (R) (H2JXL4) Permease (M) (H2JXL5) ATPase (C) (H2JXL6)
3.A.1.19.4	The putative sulfate/thiosulfate transporter, YnjBCD. YnjB has 12 TMSs. The three genes encoding this system are adjacent to one encoding a thiosulfate:sulfur transferase or a rhodanese (B7L6N1).	γ-Proteobacteria	YnjBCD of E. coli YnjB (possible receptor, R) (B7L6M8) YnjC (M) (B7L6M9) YnjD (C) (B7L6N0)
3.A.1.19.5	Putative ABC transporter	Deinococcus-Thermus	ABC transporter of Deinococcus deserti Permesae (M) (C1CWI2) ATPase (C) (C1CWI3) Possible periplasmic receptor (R) (C1CWI4)
*3.A.1.20: The Brachyspira* Iron Transporter (BIT) Family (Most similar to 3.A.1.6, 3.A.1.8 and 3.A.1.11)**
3.A.1.20.1	The iron transporter, BitABCDEF	Spirochaetes	BitABCDEF of Brachyspira (Serpulina) hyodysenteriae BitA (R) BitB (R) BitC (R) BitD (C) BitE (M) BitF (M)
3.A.1.21: The Siderophore-Fe³⁺ Uptake Transporter (SIUT) Family
3.A.1.21.1	The Fe³⁺-Yersiniabactin uptake transporter, YbtPQ (Brem et al., 2001; Fetherston et al., 1999)	Proteobacteria	YbtPQ of Yersinia pestis YbtP (M-C) YbtQ (M-C)
3.A.1.21.2	The Fe³⁺-carboxymycobactin transporter, IrtAB (Rodriguez and Smith, 2006). IrtA contains an FAD-binding domain (Ryndak et al., 2010).	Actinobacteria	IrtAB of Mycobacterium tuberculosis IrtA (M-C) (P63391) IrtB (M-C) (P63393)
3.A.1.22: The Nickel Uptake Transporter (NiT) Family
3.A.1.22.1	Nickel (Ni²⁺) porter	Proteobacteria	CbiKMQO of Actinobacillus pleuropneumoniae CbiK (R) CbiM (M) CbiQ (M) CbiO (C)
3.A.1.23: The Nickel/Cobalt Uptake Transporter (NiCoT) Family
3.A.1.23.1	Nickel (Ni²⁺) porter (Chen and Burne, 2003)	Firmicutes	UreMQO of Streptococcus salivarius UreM (M) (Q79CJ1) UreQ (M) (Q79CJ0) UreO (C) (Q79CI9)
3.A.1.23.2	Putative cobalt (Co²⁺) porter (Chen and Burne, 2003)	Firmicutes	CbiMQOK of Clostridium acetobutylicum CbiM (M) (AAK79333) CbiQ (M) (AAK79335) CbiO (C) (AAK79336) CbiK (Auxiliary?) (AAK79334)
3.A.1.23.3	Cobalt (Co²⁺) porter	δ-Proteobacteria	Cbi M(N)OQ of Geobacter sulfurreducens Cbi M(N) (D7AE13) CbiO (D7AE10) CbiQ (D7AE11)
3.A.1.24: The Methionine Uptake Transporter (MUT) Family (Similar to 3.A.1.3 and 3.A.1.12)
3.A.1.24.1	The L- and D-methionine porter (also transports formyl-L-methionine) (Zhang et al., 2003). The 3.7A structure of MetNI has been solved. An allosteric regulatory mechanism operates at the level of transport activity so increased intracellular levels of the transported ligand stabilize an inward-facing, ATPase-inactive state of MetNI to inhibit further ligand translocation into the cell (Kadaba et al., 2008).	Proteobacteria	MetNIQ (abc-yaeE-yaeC) of E. coli MetN (C) AAC73310 MetI (M) AAC73309 MetQ (R) AAC73308
3.A.1.24.2	The L- and D-methionine porter (also transports methionine sulfoxide (Hullo et al., 2004)	Firmicutes	MetNPQ (YusCBA) of Bacillus subtilis MetN (C) CAB15264 MetP (M) CAB15263 MetQ (R) CAB15262
3.A.1.24.3	The methionine porter, AtmBDE (Sperandio et al., 2007)	bacteria	AtmBDE of Streptococcus mutans AtmB (R) (Q8K8K9) AtmD (C) (Q8K8K8) AtmE (M) (Q8K8K7)
3.A.1.24.4	L-Methionine uptake porter, MetQNI	Bacteria	MetQNI of Corynebacterium glutamicum MetQ (R) (Q8NSN1) MetN (C) (Q8NSN2) MetI (M) (Q8NSN3)
3.A.1.24.5	L-Histidine uptake porter, MetIQN (Johnson et al. 2008)	Proteobacteria	MetIQN of Pseudomonas aeruginosa MetI (M) (Q9HT69) MetQ (R) (Q9HT68) MetN (C) (Q9HT70)
3.A.1.25: The Biotin Uptake Transporter (BioMNY) Family
3.A.1.25.1	The biotin uptake porter (binding receptor lacking) (see also the VUT or ECF family; BioY; 2.A.88.1.1) (Rodionov et al., 2006; Hebbeln et al., 2007). BioN (the EcfT component of the biotin transporter) appears to be required for intramolecular signaling and subunit assembly (Neubauer et al., 2009). The Ala-Arg-Ser and Ala-Arg-Gly signatures in BioN are coupling sites to the BioM ATPases (Neubauer et al., 2011). Subunit stoicheometries have been estimated with the prediction that there are oligomeric forms of BioM and BioY in the BioMNY complex (Finkenwirth et al. 2010).	Bacteria	BioMNY of Rhizobium etli BioM (C) (226 aas; 0 TMSs; Q6GUB2) BioN (M) (202 aas; 5 TMSs; Q6GUB1) BioY (M) (189 aas; 6 TMSs; Q6GUB0)
3.A.1.25.2	Putative biotin Ecf transporter, EcfSAA'T (function assigned based on genome context analyses).	Archaea	Putative Ecf transporter, EcfSAA'T, of Methanospirillum hungatei EcfS (M) (Q2FUL6) EcfA (C) (Q2FUL5) EcfA' (C) (Q2FUM0) EcfT (M) (Q2FNH6)
3.A.1.25.3	Putative biotin Ecf transporter, EcfSAA'T (function assigned based on genome context analyses).	Archaea	The putative EcfSAA'T transporter of Methanocorpusculum labreanum Ecf5 (A2SPQ3) EcfA (A2SPQ4) EcfA' (A2SPQ5) EcfT (A2SPQ6)
3.A.1.25.4	The biotin uptake system, BioMNY. The 3-d structure of the EcfS subunit, BioY, at 2.1Å resolution is known (Berntsson et al., 2012). BioY and ThiT from L. lactis show similar N-terminal structures for interaction with the ECF module but divergent C-terminal structures for substrate binding. BioY alone binds biotin but doesn''t transport it (Berntsson et al., 2012). Ala-Arg-Ser and Ala-Arg-Gly signatures in BioN are probably coupling sites to the two BioM ATPase subunits (Neubauer et al., 2011 Neubauer et al., 2011).	Bacteria	BioMNY of Lactococcus lactis BioM (A) (A2RI01) BioN (T) (A2RI03) BioY (S) (A2RMJ9)
3.A.1.25.5	Biotin/Riboflavin ECF transport system, EcfAA'T/RibU/BioY (Karpowich and Wang 2013).	Bacteria	EcfAA''T/RibU/BioY of Thermatoga martima EcfA (C) (Q9WY65) EcfA'' (C) (Q9X1Z1) EcfT (M) (Q9X2I1) BioY (M) (Q9X1G6) RibU (M)�(Q9WZQ6)
3.A.1.25.6	Riboflavin ECF transport system, EcfAA'T/RibU (Karpowich and Wang 2013).	Bacteria	EcfAA'T/RibU of Streptococcus thermophilus EcfA (C) (Q5M244) EcfA' (C) (Q5M243) EcfT (M) (Q5M245) RibU (M) (Q5M614)
3.A.1.26: The Putative Thiamine Uptake Transporter (ThiW) Family
3.A.1.26.1	The putative ABC porter (COG4732), ThiW; 718 aas; 5 TMSs; domain order: M-C-C; plus the putative ATPase binding subunit, CbiQ homologue (binding receptor unknown) (Rodionov et al., 2009)	Bacteria	ThiW/CbiQ of Chloroflexus aurantiacus ThiW MCC (SAA) (A9WGB0) CbiQ M (T) (A9WGA9)
3.A.1.26.2	ThiW homologue/CbiQ homologue (ThiW: 647 aas; M-C-C; 5-6TMSs) (Rodionov et al., 2009)	Archaea	ThiW/ChiQ of Methanocorpusculum labreanum ThiW MCC (SAA) (A2SPE8) CbiQ M (T) (A2SPE9)
3.A.1.26.3	ThiW homologue (711 aas; M-C-C) (No known binding receptor) plus a CbiQ homologue (Rodionov et al., 2009)	Bacteria	ThiW/CbiQ homologues of Actinomyces odontolyticus ThiW MCC (SAA) (A7BAX2) CbiQ M (T) (A7BAX3)
3.A.1.26.4	ThiW/CbiQ homologues (ThiW: 697 aas; M-C-C) (No known binding receptor) (Rodionov et al., 2009)	Bacteria	ThiW/CbiQ homologues of Mycobacterium tuberculosis ThiW MCC (SAA) (P63399) CbiQ M (T) (P64997)
3.A.1.26.5	ThiW/CbiQ/CbiO homologues (ThiW: 174 aas; 5 putative TMSs) (Rodionov et al., 2009)	Bacteria	ThiW/CbiQ/CbiO homologues of Roseiflexus castenholzii ThiW (M) (S) (A7NRF9) CbiQ (M) (T) (A7NRG1) CbiO C-C (A-A) (A7NRG0)
3.A.1.26.6	The ThiW/CbiQ/CbiO1/CbiO2 homologues (ThiW: 184 aas; 1-6 TMSs) (Rodionov et al., 2009)	Archaea	ThiW/CbiQ/CbiO1/CbiO2 homologues of Aeropyrum pernix ThiW M (S) (Q9Y974) CbiQ M (T) (Q9Y982) CbiO1 C (A) (Q9Y979) CbiO2 C (A) (Q9Y977)
3.A.1.26.7	The putative hydroxyethyl thiazole (biosynthetic precursor of thiamine) porter, ThiW-EcfA1-A2-EcfT (this is a group II ECF transporter which uses a universal energy-coupling module (EcfA1-EcfA2-EcfT) in many firmicutes; Rodionov et al., 2002).	Bacteria	ThiW-EcfA1-EcfA2-EcfT of Enterococcus faecalis ThiW (M) (Q830K3) EcfA1 (C) (Q839D5) EcfA2 (C) (Q839D4) EcfT (M) (Q839D3)
3.A.1.26.8	Putative biotin Ecf transporter, EcfSAT	Archaea	Putative Ecf transpoter, EcfSAT, of Archaeoglobus fulgidus S-subunit (M) (O29098) A-subunit (C) (O29097) T-subunit (M) (O29096)
3.A.1.26.9	The folate transporter, FolT/EcfAA''T (The 3-d structure is known to 3.0� resolution (Xu et al. 2013; 4HUQ).� This transporter uses the same ECF energy coupling complex (AA''T) as 3.A.1.28.2.	Firmicutes	FolT/EcfAA'T of Lactobacillus brevis FolT (M) (Q03S56) EcfA (C) (Q03PY6) EcfA' (C) (Q03PY7) EcfT (M) (Q03PY5)
3.A.1.27: The γ-Hexachlorocyclohexane (HCH) Family (Similar to 3.A.1.12 and 3.A.1.24)
3.A.1.27.1	The γ-hexachlorocyclohexane (γHCH) uptake permease, LinKLMN (most similar to 3.A.1.12.4, the QAT family) (Endo et al., 2007)	Bacteria	LinKLMN of Sphingobium japonicum LinK (M) (BAF51698) LinL (C) (BAF51699) LinM (R) (BAF51700) LinN (lipoprotein) (BAF51701)
3.A.1.27.2	The chloroplast lipid (trigalactosyl diacyl glycerol (TDG)) transporter, Tdg1,2,3 (Lu et al., 2007). Lipids such as mono- and digalactolipids are synthesized in the endoplasmic reticulum (ER) of plant cells and transferred to the thylakoid membranes of chloroplasts. Mutations in an outer chloroplastic envelope protein with 350 aas and 7 putative TMSs in the last 250 residues may catalyze translocation as part of a lipid transfer complex (Xu et al., 2003; Roston et al. 2012).	Plant Chloroplast	Tdg 1,2,3 of Arabidopsis thaliana: Tdg1 (M) (Q8L4R0) Tdg2 (R) (Q3EB35) Tdg3 (C) (Q9AT00)
3.A.1.27.3	ABC transporter maintaining outer membrane (OM) lipid asymmetry, MlaABCDEF (Malinverni and Silhavy, 2009). MlaA (VacJ) is a "spreading" protein, essential for Shigella pathogenicity (Suzuki et al., 1994).	Actinobacteria	MlaABCDEF of E. coli MlaA, OM lipoprotein component (251aas) (P76506) MlaB, cytoplasmic STAS component (97aas) (P64602) MlaC, periplasmic binding receptor (R) (211aas) (P0ADV7) MlaD, anchored periplasmic binding receptor (R) (183aas) (P64604) MlaE, inner membrane permease component (M) (260aas) (P64606) MlaF, ATP binding protein (C) (269aas) (P63386)
3.A.1.27.4	The cholesterol uptake porter (Mohn et al., 2008). Takes up cholesterol, 5-α-cholestanol, 5-α-cholestanone, β-sitosterol, etc. (It is not established that all of these proteins comprise the system or that other gene products are not involved.)	Actinobacteria	Cholesterol uptake porter of Rhodococcus jostii YrbE4A (ro04696; 254aas; 5-6 TMSs) (M) (Q0S7K4) YrbE4B (ro04697; 283aas; 5 TMSs) (M) (Q0S7K3) MceE4A (ro04698; 391aas; 1 N-terminal TMS) (R) (Q0S7K2) MceE4B (ro04699; 338aas; 1 N-terminal TMS) (R) (Q0S7K1) MlkA (ro01974; 363aas; 0 TMSs) (C) (Q0SFA1) MlkB (ro01744; 346aas; 0 TMSs) (C) (Q0SD37)
3.A.1.27.5	The Mce/Yrb/Mlk (Mammalian cell entry) ABC-type putative steroid uptake transporter (involved in several aspects of mycobacterial pathogenesis) (Mohn et al., 2008; Joshi et al., 2006).	Bacteria	The Mce transporter of Mycobacterium tuberculosis H37Rv YrbE4A (M) (254aas; 6 TMSs) (O53546) YrbE4B (M) (280aas; 5 TMSs) (O53545) MceA (R) (242aas; 1 TMS) (O06356) MceB (R) (244aas; 1 TMS) (O07422) Mlk (C) (Mkl; MceG; 359aas; 0 TMSs) (P63357)
3.A.1.28: The Queuosine (Queuosine) Family
3.A.1.28.1	The putative queuosine uptake transporter, QrtTUVW (Rodionov et al., 2009) (most similar to 2.A.88.2.1)	Bacteria	QrtTUVW of Salmonella enterica su. typh. QrtT (M) (Q8XGV9) QrtU (M) (Q8Z3V9) QrtV (C) (Q8Z3V8) QrtW (C) (Q8Z3V7)
3.A.1.28.2	The folate transporter, FolT/EcfAA''T (The 3-d structure is known to 3.0� resolution (Xu et al. 2013; 4HUQ)	Firmicutes	EcfAA'ST of Lactobacillus brevis EcfA (C) (Q03PY5) EcfA' (C) (QO3PY6) EcfS (M) (QO3NM0) EcfT (M) (Q03PY7)
3.A.1.29: The Methionine Precursor (Met-P) Family
3.A.1.29.1	The putative methionine precursor/uptake transporter, MtsTUV (T is most similar to 3.A.1.23.2; U is most similar to 2.A.36.7.1 and 3.A.1.14.2; V is most similar to 3.A.1.23.2 and 3.A.1.25.1) (Rodionov et al., 2009)	Bacteria	MtsTUV of Lactobacillus johnsoni MtsT (M) (Q74I63) MtsU (C) (Q74I62) MtsV (M) (Q74I61)
3.A.1.30: The Thiamin Precursor (Thi-P) Family
3.A.1.30.1	The putative thiamin precursor uptake transporter, YkoEDC (Rodionov et al., 2009) (E is most similar to 3.A.1.4.3; D is most similar to 3.A.1.26.2; C is most similar to 3.A.1.23.2).	Bacteria	YkoEDC of Bacillus subtilis YkoE (M) (O34738) YkoD (C-C) (O34362) YkoC (M) (O34572)
3.A.1.30.2	Putative thiamin transporter	Firmicutes	Potential thiamin transporter of Streptococcus pneumoniae Membrane Protein 1 (Q97RJ2) ABC ATPase (Q97RS3) Membrane Protein 2 (Q97RS4)
3.A.1.31: The Unknown-ABC1 (U-ABC1) Family
3.A.1.31.1	The putative uptake transporter of unknown substrate specificity, HtsTUV (Rodionov et al., 2009)	Bacteria	HtsTUV of Bifidobacterium longum HtsT (M) (Q8G6E7) HtsU (M) (Q8G6E8) HtsV (C-C) (Q8G6E9)
3.A.1.31.2	EcfSTAA of unknown function.	Bacteria	EstSTA of Treponema denticola EstS (Q73JF1) EstT (Q73JF2) EstAA (Q73JF3)
3.A.1.32: The Cobalamin Precursor (B₁₂-P) Family
3.A.1.32.1	The putative cobalamin precursor uptake transporter, CbrTUV (Rodionov et al., 2009) (CbrT is most similar to 2.A.1.15.1; CbrU is most similar to 3.A.1.26.1 (MFS; e^-4); CbrV is most similar to 2.A.53.11.1 and 3.A.1.2.2 (score of 0.035)) (CbrT has 6 putative TMSs; CbrV has 8-10 putative TMSs).	Bacteria	CbrTUV of Streptomyces coelicolor CbrT (M) (Q9KXJ5) CbrU (C-C) (Q9KXJ6) CbrV (M) (Q9KXJ7)
3.A.1.32.2	Putative vitamin transporter, EcfSTAA	Archaea	Putative vitamin transporter of Methanosphaera stadtmanae, EcfSTAA' EcfT (M) (Q2NFA7) EcfA-A' (C) (Q2NFA8) EcfS (M) (Q2NFA9)
3.A.1.33: The Methylthioadenosine (MTA) Family
3.A.1.33.1	The putative methylthio adenosine uptake transporter (Rodionov et al., 2009). MtaTUV (MtaT and MtaU are most similar to 3.A.1.26.1 (ThiW); MtaV is most similar to 3.A.1.25.1 (BioN) and 3.A.1.23.2 (CbiQ)).	Bacteria	MtaTUV of Thermoanaerobacter tengcongensis MtaT (M) (Q8R9M1) MtaU (C-C) (Q8R9L8) MtaV (M) (Q8R9L9)
3.A.1.34: The Tryptophan (TrpXYZ) Family
3.A.1.34.1	The putative tryptophan uptake transporter, TrpXYZ. Regulated by tryptophan-specific T-box (Vitreschak et al. 2008)	Bacteria	TrpXYZ of Streptococcus pyogenes TrpX (R) (Q99ZY6) TrpY (M) (Q99ZY4) TrpZ (C) (Q99ZY3)
3.A.1.35: The Cobalamin Precursor/Cobalt (CPC) Family
The putative cobalamin precursor/cobalt (CPC) transporter family includes proteins of about 190 aas with 4-6 TMSs. These proteins are encoded in operons that are subject to regulation by vitamin B₁₂ (Rodionov et al., 2003), which is similar to members of 3.A.1.32; however, members of these two families show divegent sequences. They are found in chloroflexi, cyanobacteria, and Firmicutes. Their functions have not been characterized.
3.A.1.35.1	Putative ECF transporter, EcfSTA; regulated by a cobalamin riboswitch.	Bacteria	EcfSTA of Roseifluxes sp. RS-1 EcfS (S) (A5UXW2) EcfT (T) (A5UXW1) EcfA (A) (A5UXW0)
3.A.1.35.2	Putative Co²⁺ ECF transporter, EcfSTA	Bacteria	EcfSTA of Gloeobacter violaceus EcfS (S) (Q7NIY0) EcfT (T) (Q7NIX9) EcfA (A) (Q7NIX8)
3.A.1.35.3	Putative Co²⁺ ECF transporter, EcfSTA	Bacteria	EcfSTA of Syntrophobotulus glycolicus EcfS (S) (F0SWZ4) EcfT (T) (F0SWZ5) EcfA (A) (F0SWZ6)
3.A.1.101: The Capsular Polysaccharide Exporter (CPSE) Family
3.A.1.101.1	Capsular polysaccharide exporter	Gram-negative bacteria	KpsMT of E. coli KpsM KpsM (M) - (P24584) KpsT (C) - (P24586)
3.A.1.101.2	Vi polysaccharide exporter, VexBC (Hashimoto et al, 1993).	Gram-negative bacteria	VexBC of Salmonella typhi VexB (M) - (P43109) VexC (C) - (P43110)
3.A.1.101.3	Capsular polysialate exporter, CtrC/D (functions with 1.B.18.2.3 (OMA) and 1.B.4.2.1 (MPA2)) (Larue et al., 2011).	Bacteria	CtrABCD of Neisseria meningitidis CtrC (M) (B3FHE1) CtrD (C) (B3FHE0)
3.A.1.102: The Lipooligosaccharide Exporter (LOSE) Family
3.A.1.102.1	Lipooligosaccharide exporter (nodulation proteins, NodIJ)	Gram-negative bacteria	NodIJ of Rhizobium galegae NodJ (M) NodI (C)
3.A.1.103: The Lipopolysaccharide Exporter (LPSE) Family
3.A.1.103.1	Lipopolysaccharide exporter	Gram-negative bacteria	RfbAB of Klebsiella pneumoniae RfbA (M) RfbB (C)
3.A.1.103.2	Heteropolysaccharide O-antigen exporter (Feng et al., 2004). The C-terminal cytoplasmic domain of Wzt (a IgG-like β-sandwich) determines the specificity of the transporter for either O8 or O9a O-PS (Cuthbertson et al., 2007).	Gram-negative bacteria	Wzm/Wzt of E. coli Wzm (M) (AAS99164) Wzt (C) (AAS99165)
3.A.1.104: The Teichoic Acid Exporter (TAE) Family
3.A.1.104.1	Teichoic acid exporter, TagGH. Appears to be present in a large complex with the teichoic acid precursor synthetic enzymes (Formstone et al. 2008). The substrate may be the diphospholipid linked disaccharide portion of the teichoic acid precursor (Schirner et al. 2011).	Gram-positive bacteria	TagGH of Bacillus subtilis TagG (M) TagH (C)
3.A.1.104.2	The teichoic acid exporter, TarGH. May be specific for the diphospholipid linked disaccharide portion of the teichoic acid precursor (Schirner et al. 2011). TarG is the target of a small antimicrobial inhibitor of S. aureus growth (Swoboda et al. 2009).	Firmicutes	TarGH of Staphylococcus aureus TarG (M) (D1GQ18) TarH (C) (D1GQ17)
3.A.1.105: The Drug Exporter-1 (DrugE1) Family
3.A.1.105.1	Daunorubicin; doxorubicin (drug resistance) exporter	Gram-positive bacteria	DrrAB of Streptomyces peucetius DrrA (C) DrrB (M)
3.A.1.105.2	Oleandomycin (drug resistance) exporter	Gram-positive bacteria	OleC4-OleC5 of Streptomyces antibioticus OleC4 (C) OleC5 (M)
3.A.1.105.3	The 4A-4E-O-dideacetyl-chromomycin A₃ (biosynthetic precursor of chromomycin) exporter (may also export chromomycin and mithramycin (Menendez et al., 2007).	Gram-positive Bacteria	CmrAB of Streptomyces greseus CmrA(C) (Q70J75) CmrB(M) (Q70J76)
3.A.1.105.4	The pyoluteorin efflux pump, PltHIJKN	γ-Proteobacteria	PltHIJKN of Pseudomonas sp. M18: PltH (336aas; MFP) - (Q4VWD0) PltI (589aas; C-C) - (Q4VWC9) PltJ (377aas; M; COG0842; similar to 9.B.74.2 (ABC-2)) - (Q4VWC8) PltK (372aas; M; The C-terminal hydrophobic half has 5TMSs and is most similar to PltJ, and then to 9.B.74.2, but it is also homologous to 3.A.1.105.2 and 3.A.1.102.1) - (Q4VWC7) PltN (480aas; OMF) - (Q4VWC6)
3.A.1.105.5	AbcG homologue	Animals	AbcG homologue of Drosophia melanogaster
3.A.1.105.6	The ABC-2-like transporter	Bacteria	ABC-2-like transporter of Dehalococcoides ethenogenes ABC2 protein (M) (Q3Z8A7) ATPase (C) (Q3Z8A8)
3.A.1.105.7	Putative ABC2 tranport system, SagGHI; may export streptolysin S.	Firmicutes	Putative Streptolysin ABC2 tranport system, SagGHI. SagG (C) (Q9A0K0) SagH (M) (Q9A0J9) SagI (M) (Q9A0J8)
3.A.1.105.8	ABC-2 transporter. The two genes encoding this system are adjacent to one encoding an squalene-hopene cyclase that coverts squalene to hopene. The substrate could therefore be hopene or a hydrocarbon triterpene derivative of it (Racolta et al. 2012).	Planctomycetes	ABC2 membrane protein (Q7UE57) and ATPase (Q7UE58) of Rhodopirellula baltica
3.A.1.105.9	ABC2 membrane proteins (J7ZHK9 and J8A8S6) with ATPase (J8ABC0) transporter	Firmicutes	ABC2 transporter of Bacillus cereus
3.A.1.105.10	AbcG homologue	Animals	AbcH of Danio rerio (F1QZ58)
3.A.1.105.11	ABC-2 transporter probably specific for a lantibiotic.� The genes for this system are adjacent to an S2P-M50 peptidase (G0Q3D2), probably involved in pro-lantibiotic processing, as well as a lantibiotic biosynthetic enzyme (G0Q3D1) and a lantibiotic dehydratase (G0Q3D0).�	Actinobacteria	ABC-2/ATPase of Streptomyces griseus ABC-2 (M) (G0Q3D4) ATPase (C) (G0Q3D3)
3.A.1.105.12	ABC-2 transporter with ABC ATPase	Archaea	ABC transporter ABC2 (M) (F8D412) ABC ATPase (C) (F8D413)
3.A.1.106: The Lipid Exporter (LipidE) Family
3.A.1.106.1	Phospholipid, LPS, lipid A and drug exporter (flippase) (Eckford and Sharom, 2010). MsbA (essential for export to the outer membrane). MsbA also confers drug resistance to azidopine, daunomycin, vinblastine, Hoechst 33342 and ethidium (Reuter et al., 2003). Four x-ray structures, trapped in different conformations, two with and two without nucleotide, have been solved (Ward et al., 2007). They suggest an alternating accessibility mode of transport with major conformational changes.	Gram-negative bacteria	MsbA (M-C) of E. coli
3.A.1.106.2	The homodimeric Sav1866 multidrug exporter (transports doxorubicin, verapamil, ethidium, tetraphenylphosphonium, vinblastine and the fluorescent dye, Hoechst 33342; 3-D structure known at 3 Å resolution; Dawson and Locher, 2006; Velamakanni et al., 2008) The empty site opens by rotation of the nucleotide-binding domain whereas the ATP-bound site remains occluded (Jones and George, 2011). Conformational changes induced by ATP-binding and hydrolysis have been proposed (Becker et al. 2010; Becker et al. 2010; Oliveira et al., 2011).	Gram-positive Bacteria	Sav1866 of Staphylococcus aureus (M-C) 2HYDA/2HYDB (578 aas)
3.A.1.106.3	The dimeric multidrug resistance exporter, ABC1/2 (exports the peptide antimicrobrials, nisin and polymyxin; (Margolles et al., 2006) (both ABC1 and ABC2 also show striking similarity to family 3.A.1.117).	Gram-positive Bacteria	ABC1/2 of Brevibacterium longum: ABC-1 (M-C) (ZP_00121338) ABC-2 (M-C) (ZP_00121339)
3.A.1.106.4	The duplicated ABC transporter, CgR_1214 (1247 aas; MC(poorly conserved) MC(well conserved))	Bacteria	CgR_1214 of Corynebacterium glutamicum (MCMC) (A4QD95)
3.A.1.106.5	The heterodimeric multidrug efflux pump, SmdAB (exports norfloxacin, tetracycline, 4',6-diamidino-2-phenylindole (DAPI), and Hoechst 33342) (Matsuo et al., 2008).	Bacteria	SmdAB of Serratia marcescens: SmdA (M-C) (A7VN01) SmdB (M-C) (A7VN02)
3.A.1.106.6	Multidrug efflux pump, Rv0194 (exports & causes resistance to ampicillin, streptomycin and chloramphenicol by 32- to 64-fold and to vancomycin and tetracycline by 4- to 8-fold (Danilchanka et al., 2008)).	Bacteria	Rv0194 of Mycobacterium tuberculosis (MCMC) (O53645)
3.A.1.106.7	The Salmochelin/Enterobactin secretory exporter, IroC (Crouch et al., 2008).	Bacteria	IroC of Salmonella enterica (MCMC) (Q8RMB7)
3.A.1.106.8	The heterodimeric BmrC/BmrD (YheHI) MDR transporter.� Transports a wide range of structurally unrelated drugs including doxyrubicin, mitoxantrone, ethidium, and hoechst 33342 (Torres et al., 2009). It activates the sensor kinase, KinA, during sporulation initiation (Fukushima et al. 2006). Large scale purification has been achieved (Gali�n et al. 2011).� It has been reconstituted in giant unilamellar vesicles (Dezi et al. 2013).	Bacteria	BmrC/BmrD (YheHI) of Bacillus subtilis YheH (M-C) (O07549) YheI (M-C) (O07550)
3.A.1.107: The Putative Heme Exporter (HemeE) Family
3.A.1.107.1	Putative heme exporter, CcmABC=CycVWZ (Note: CcmC may function independently of CcmAB) (Feissner et al., 2006; Christensen et al., 2007)	Gram-negative bacteria	CycVWZ of Bradyrhizobium japonicum CycV (C) CycW (M) CycZ (M)
3.A.1.107.2	The mitochondrial ABC transporter involved in cytochrome c maturation, CcmA/CcmB. (Note: CcmA is nuclearly encoded while CcmB is mitochondrially encoded) (Rayapuram et al., 2007)	Plant Mitochondria	CcmA/CcmB of Arabidopsis thaliana CcmA (C) (Q9C8T1) CcmB (M) (P93280)
3.A.1.107.3	CcmABCD exporter; CcmD (69aas, 1TMS) is required for the release of CcmE (which binds heme in the periplasm) from CcmABC. CcmC (9.B.14.2.3) is required for the transfer of heme to CcmE in the periplasm (Richard-Fogal et al., 2008) In the presence of heme, CcmC and CcmE form a stable complex (Richard-Fogal & Kranz, 2010).	Proteobacteria	CcmABCD of E. coli CcmA (C) (Q8XE58) CcmB (M; 7 TMSs) (P0ABM0) CcmC (M; 6 TMSs) (P0ABM1) CcmD (M; 1 TMS) (P0ABM7)
3.A.1.107.4	Cytochrome c maturation system (heme exporter?), CcmA/B	γ-Proteobacteria	CcmAB of Pseudomonas virdiflava CcmA (C) (K6BJ24) CcmB (M) (K6BIH6)
3.A.1.108: The β-Glucan Exporter (GlucanE) Family
3.A.1.108.1	β-Glucan exporter	Gram-negative bacteria	NdvA (M-C) of Rhizobium meliloti
3.A.1.109: The Protein-1 Exporter (Prot1E) Family
3.A.1.109.1	α-Hemolysin exporter. HlyB has an (inactive?) N-terminal C39 peptidase-like domain (Lecher et al., 2011). It is essential for secretion and interacts with the unfolded HlyA, thereby protecting it from cytoplasmic degradation (Lecher et al. 2012).	Gram-negative bacteria	HlyB (M-C) of E. coli
3.A.1.109.2	Cyclolysin exporter, CyaB (Glaser et al., 1988) (Possesses an N-terminal lysosomal sorting signal within the amino-terminal transmembrane domain; Kamakura et al., 2008).	Gram-negative bacteria	CyaB (M-C) of Bordetella pertussis
3.A.1.109.3	LapA adhesin protein exporter, LapB (Hinsa et al., 2003)	Bacteria	LapB of Pseudomonas putida LapB (MC) (AAN65800)
3.A.1.109.4	The biofilm inducible ABC-type drug resistance pumps, PA1875-PA1877 (Zhang and Mah, 2008).	Proteobacteria	PA1875-PA1877 of Pseudomonas aeruginosa PA1875 (OMF; 425 aas) (Q9I2M2) PA1876 (ABC; M-C; 723 aas) (Q9I2M1) PA1877 (MFP; 395 aas) (Q9I2M0)
3.A.1.110: The Protein-2 Exporter (Prot2E) Family
3.A.1.110.1	Microcin E492 exporter, MceFGH (MceF has 5 - 7 TMSs and is most likely a CAAX amino terminal protease that might function in the processing of microcin E492; MceG has a short hydrophilic N-terminus, a centra 6 TMS ABC domain, and a C-terminal ABC ATPase domain; MceH has 1 N-terminal TMS) (Bieler et al., 2006; Lagos et al., 1999)	Proteobacteria	MceGH of Klebsiella pneumoniae MceG (C-M-C) (Q93GK5) MceH (MFP) (Q93GK4)
3.A.1.110.2	Colicin V exporter	Enteric bacteria	CvaB (M-C) of E. coli
3.A.1.110.3	The multiple protein exporter, PrsD/PrsE (exports EPS glycanases, PlyA and PlyB, as well as Rhizobium adhering proteins) (Russo et al., 2006). 12 substrates have been identified; PrsDE provide the major route of protein export in R. leguminosarum (Krehenbrink and Downie, 2008).	Gram-negative bacteria	PrsD/PrsE of Rhizobium leguminosarum PrsD(M-C) (O05693) PrsE(MFP) (O05694)
3.A.1.110.4	Alkaline protease exporter	Gram-negative bacteria	AprD (M-C) of Pseudomonas aeruginosa
3.A.1.110.5	S-layer protein exporter	Gram-negative bacteria	RsaD (M-C) of Caulobacter crescentus
3.A.1.110.6	Exporter for lipase LipA, protease PrtA and S-layer protein SlaA, LipBCD (Akatsuka et al. 1997). LipABC is also called PrtDEF.	Gram-negative bacteria	LipBCD of Serratia marcescens LipB (M-C) (Q54456) LipC (MFP) (Q54457) LipD (OMF) (O87950)
3.A.1.110.7	Exporter for heme-binding protein, HasA and metaloprotease, PrtA. Functions as a complex spanning the two membranes of the cell envelope: HasDEF (HasD = ABC protein; HasE = the MFP; HasF = the OMF (see 2.A.6.2.31 for HasF) (Akatsuka et al. 1997).	Gram-negative bacteria	HasDEF of Serratia marcescens HasD (M-C) (Q53368) HasE (MFP) (Q57387) HasF (OMF) (Q54452)
3.A.1.110.8	Surface layer protein exporter	Gram-negative bacteria	SapD (M-C) of Campylobacter fetus
3.A.1.110.9	Exporter of HasA lipase, and alkaline protease	Gram-negative bacteria	HasD (M-C) of Pseudomonas fluorescens
3.A.1.110.10	The AlgE-type Mannuronan C-5-Epimerase exporter, EexD (PrtD) (Gimmestad et al., 2006).	Bacteria	EexD of Azotobacter vinelandii (C1DS84)
3.A.1.110.11	Secretion system for metaloprotease, PrtA, PrtDEF (Akatsuka et al. 1997). (PrtF=1.B.17.1.2)	Gram-negative bacteria	PrtDEF of Erwinia chysanthemi PrtD (M-C) (P23596) PrtE (MFP) (P23597)
3.A.1.111: The Peptide-1 Exporter (Pep1E) Family
3.A.1.111.1	Hemolysin/bacteriocin (cytolysin) exporter with associated proteolytic activity	Gram-positive bacteria	CylT (M-C) (CylB) of Enterococcus faecalis
3.A.1.111.2	Subtilin (toxic peptide) exporter	Gram-positive bacteria	SpaB (M-C) of Bacillus subtilis
3.A.1.111.3	Nisin exporter	Gram-positive bacteria	NisT (M-C) of Lactococcus lactis
3.A.1.111.4	Bacteriocin immunity protein, SmbG (198 aas; 6TMSs in a 2+2+2 arrangement. (Exports bacteriocins and causes resistance to antibiotics such as tetracycline, penicillin and triclosan). Upregulated by exposure to antibiotics (Matsumoto-Nakano and Kuramitsu, 2006)	Gram-positive bacteria	SmbG (M-C) of Streptococcus mutans (Q5TLL2)
3.A.1.111.5	The lacticin Q exporter, LcnDR3 (Yoneyama et al., 2009).	Gram-positive bacteria	LcnDR3 (M-C) of Lactococcus lactis (P37608)
3.A.1.111.6	Salivericin 9 exporter, SivT (692 aas; 6 TMSs) (Wescombe et al., 2011)	Firmicutes	SivT of Strepococcus salivarius (F8LI02)
3.A.1.112: The Peptide-2 Exporter (Pep2E) Family
3.A.1.112.1	Competence factor (CSF; a heptadecapeptide) exporter.	Gram-positive bacteria	ComA (M-C) of Streptococcus pneumoniae (functions with putative MFP accessory protein, ComB)
3.A.1.112.2	Pediocin PA-1 exporter	Gram-positive bacteria	PedD (M-C) of Pediococcus acidilactici
3.A.1.112.3	Bacteriocin (lactococcin) exporter.	Gram-positive bacteria	LcnC (M-C) of Lactococcus lactis (functions with putative MFP accessory protein LcnD)
3.A.1.112.4	Sublancin exporter, SunT	Gram-positive bacteria	SunT (M-C) of Bacillus subtilis
3.A.1.112.5	Exporter of the BlpC peptide pheromone (B5E242) and several bacteriocins, BlpAB (Kochan and Dawid 2013).	Firmicute	BlpAB of Streptococcus pneumoniae BlpA (M-C) (B3E244) BlpB (MFP) (B3E242)
3.A.1.113: The Peptide-3 Exporter (Pep3E) Family
3.A.1.113.1	Modified cyclic peptide (syringomycin) exporter, SyrD	Gram-negative bacteria	SyrD (M-C) of Pseudomonas syringae
3.A.1.113.2	Pyoverdin (siderophore) exporter	Gram-negative bacteria	PvdE (M-C) of Pseudomonas aeruginosa
3.A.1.113.3	The microcin J25 (21 aa cyclic peptide antibiotic) exporter, YojI (Delgado et al., 2005) (TolC is also required for export; Vincent and Morero, 2009). Also exports L-cysteine (Yamada et al., 2006).	Gram-negative bacteria	YojI of E. coli (P33941)
3.A.1.114: The Probable Glycolipid Exporter (DevE) Family
3.A.1.114.1	Glycolipid exporter (under nitrogen control in heterocysts), DevABC-HgdD (Moslavac et al., 2007). Heterocyst envelope glycolipids (HGLs) function as an O₂ diffusion barrier, being deposited over the heterocyst outer membrane, surrounded by an outermost heterocyst polysaccharide envelope. DevBCA and TolC form an ATP-driven efflux pump required for the export of HGLs across the Gram-negative cell wall (Staron et al., 2011). DevB, the MFP, must be hexameric to create a functional export complex.	Cyanobacteria	DevABC-HgdD of Anabaena variabilis (sp. strain PCC7120) DevA (C) DevB (MFP) DevC (M) HgdD (TolC like)
3.A.1.115: The Na⁺ Exporter (NatE) Family
3.A.1.115.1	Na efflux pump NatAB	Gram-positive bacteria	NatAB of Bacillus subtilis NatA (M) NatB (C)
3.A.1.115.2	Putative Na extrusion pump, NatAB.� NatB has an N-terminal NatB domain (residues 1 - 375) as well as a C-terminal CAAX protease domain (9.B.2; residues 380 - 650).	Planctomycetes	NatAB of Rhodopirellula baltica
3.A.1.116: The Microcin B17 Exporter (McbE) Family
3.A.1.116.1	Microcin B17 exporter	Enteric bacteria	McbEF of E. coli McbE (M) McbF (C)
3.A.1.117: The Drug Exporter-2 (DrugE2) Family
3.A.1.117.1	The multidrug exporter, LmrA (can also substitute for MsbA [TC #3.A.1.106.1] to export lipid A; Reuter et al., 2003).	Gram-positive bacteria	LmrA (M-C) of Lactococcus lactis
3.A.1.117.2	Hop resistance protein, HorA.� Reconstitution in phosphatidyl ethanolamine bilayers resulted in normal activity, but reconstitution in phosphatidly choline resulted in uncoupling of ATP hydrolysis from transport and a change in the orientations of the TMSs (Gustot et al. 2010).	Gram-positive bacteria	HorA (M-C) of Lactobacillus brevis
3.A.1.118: The Microcin J25 Exporter (McjD) Family
3.A.1.118.1	The cyclic peptide antibiotic, microcin J25 exporter, McjD (TolC is also required for export; Vincent and Morero, 2009).	Gram-negative bacteria	McjD (M-C) of E. coli
3.A.1.119: The Drug/Siderophore Exporter-3 (DrugE3) Family
3.A.1.119.1	5-Hydroxystreptomycin and other streptomycin-like aminoglycoside exporter, StrVW	Gram-positive bacteria	StrVW of Streptomyces glaucescens StrV (M-C) StrW (M-C)
3.A.1.119.2	Tetracycline/oxytetracycline/oxacillin exporter, TetAB	Gram-positive bacteria	TetAB (StrAB) of Corynebacterium striatum TetA (M-C) TetB (M-C)
3.A.1.119.3	Exochelin exporter, ExiT	Gram-positive bacteria	ExiT of Mycobacterium smegmatis (MC-M-C)
3.A.1.120: The (Putative) Drug Resistance ATPase-1 (Drug RA1) Family
3.A.1.120.1	Macrolide ATPase (membrane constituent unknown)	Gram-positive bacteria	SrmB (C-C) of Streptomyces ambofaciens
3.A.1.120.2	Tylosin ATPase (membrane constituent unknown)	Gram-positive bacteria	TlrC (C-C) of Streptomyces fradiae
3.A.1.120.3	Oleandomycin resistance ATPase (membrane constituent unknown)	Gram-positive bacteria	OleB (C-C) of Streptomyces antibioticus
3.A.1.120.4	Carbomycin resistance ATPase (membrane constituent unknown)	Gram-positive bacteria	Carbomycin, CarA (C-C), protein of Streptomyces thermotolerans
3.A.1.120.5	The acetate resistance ABC acetate exporter (Nankano et al., 2006)	Gram-negative bacteria	AatA (C-C) of Acetobacter aceti (BAE71146)
3.A.1.120.6	The Uup protein (required for bacterial competitiveness (Murat et al., 2008); 39% identical to 3.A.1.120.5).	Gram-negative bacteria	Uup of E. coli (P43672)
3.A.1.121: The (Putative) Drug Resistance ATPase-2 (Drug RA2) Family
3.A.1.121.1	Erythromycin ATPase (membrane constituent unknown)	Gram-positive bacteria	MsrA (C-C) of Staphylococcus epidermidis
3.A.1.121.2	Pristinamycin resistance protein, VgaG	Gram-positive bacteria	VgaB (C-C) of Staphylococcus aureus
3.A.1.121.3	Antibiotic (virginiamycin and lincomycin) resistance protein, VmlR	Gram-positive bacteria	VmlR (C-C) of Bacillus subtilis (P39115)
3.A.1.121.4	The two component ABC-4-type transporter (Rafii and Park, 2008). Transports multiple drugs including ethidium and fluoroquinolones.	Bacteria and archaea	The ABC-4 M/C-C transporter of Clostridium hathewayi (Q83XH0) (Q83XH1)
3.A.1.122: The Macrolide Exporter (MacB) Family
3.A.1.122.1	Macrolide (14- and 15- but not 16-membered lactone macrolides including erythromycin) exporter, MacAB (both MacA and MacB are required for activity) (Tikhonova et al., 2007). MacAB also functions (probably with TolC) to export heat-stable enterotoxin II (Yamanaka et al., 2008). The crystal structure of MacA is available (Yum et al., 2009). MacB is a dimer whose ATPase activity and macrolide-binding capacity are regulated by the membrane fusion protein MacA (Lin et al., 2009). Xu et al. (2009) have reported the crystal structure of the periplasmic region of MacB. Also exports L-cysteine (Yamada et al., 2006). The periplasmic membrane proximal domain of MacA acts as a switch in stimulation of ATP hydrolysis by the MacB transporter (Modali and Zgurskaya, 2011).	Gram-negative bacteria	MacAB of E. coli: MacA(MFP) (P75830) MacB(C-M) (P75831)
3.A.1.122.2	The SpdC antimicrobial peptide resistance efflux pump, YknWXYZ (Butcher and Helmann, 2006; Yamada et al., 2012). YknW interacts directly with YknXYZ.	Bacteria	YknWXYZ of Bacillus subtilis: YknW (O31709) YknX (MFP) (O31710) YknY (C) (O31711) YknZ (M) (O31712)
3.A.1.122.3	The enterocin AS-48 exporter, As-48FGH	Gram-positive bacteria	As-48FGH on plasmid pMBL of Enterococcus faecalis: As-48F (MFP) (Q7AUQ4) As-48H (M) (Q8RKC0) As-48G (C) (Q8RKC1)
3.A.1.122.4	Probable Heme exporter, HrtAB (Stauff et al., 2008)	Bacteria	HrtAB of Staphylococcus aureus: HrtA (C) (Q7A3X3) HrtB (M) (Q7A7X2)
3.A.1.122.5	ABC transporter of unknown function (DUF214 protein) (4TMSs)/ABC protein [Msed1528/Msed1530]	Archaea	Msed1528/Msed1530 of Metallosphaera sedula (M) (A4YGY2)
3.A.1.122.6	ABC transporter of unknown function (DUF214 protein) (4TMSs)/ABC protein [MA2839/MA2840]	Archaea	MA2839/MA2840 of Methanosarcina acetivorans MA2839 (M) (Q8TM31) MA2840 (C) (Q8TM30)
3.A.1.122.7	ABC transporter of unknown function (Duf214 protein (409aas; 4TMSs:1+3)/ABC protein)	Archaea	Duf214 protein/ ABC protein of Methanococcus voltae: Duf214 protein (M) (A8TDX0) ABC protein (C) (A8TDW7)
3.A.1.122.8	Putative ABC3 permease, PC1,2,3.	Bacteria	PC1,2,3 of Treponema denticola: PC1 (C) - Q73MJ2 PC2 (M) - Q73MJ3 PC3 (M) - Q73MJ4
3.A.1.122.9	Duf214 protein (405aas)/ ABC protein	Archaea	Duf214/ABC system of Caldivirga maquilingensis: Duf214 protein (M) (A8M8Z1)
3.A.1.122.10	Duf214 (423aas)/ ABC system	Archaea	Duf214/ABC system of Sulfolobus tokodaii: Duf214 protein (M) (Q973J4)
3.A.1.122.11	The hemin resistance transporter, HrtAB. Expression is activated by hemin or hemoglobin via the ChrAS transmembrane sensor kinase/response regulator system (Bibb and Schmitt 2010).	Bacteria	HrtAB of Corynebacterium diphtheriae HrtA (C) (H2GZC3) HrtB (M) (H2GZC4)�
3.A.1.122.12	Arthrofactin efflux pump, ArfDE (Balibar et al. 2005).	γ-Proteobacteria	ArfDE of Pseudomonas sp. MIS38 ArfD (MFP) (Q84BQ3) ArfE (ABC) (A0ZUB1)
3.A.1.122.13	Putative ABC3-type antimicrobial peptide transporter, fused ATPase-porter protein, U-ABC3-1b (667aas; 4TMSs:1+3)	Bacteria	U-ABC3-1b of Lactobacillus brevis (CM) (Q03RZ6)
3.A.1.123: The Peptide-4 Exporter (Pep4E) Family
3.A.1.123.1	Pep5 lantibiotic exporter, PepT	Gram-positive bacteria	PepT (M-C) of Staphylococcus epidermidis
3.A.1.123.2	Aureocin A70 multipeptide bacteriocin (AurA, AurB, AurC, AurD) exporter, AurT	Gram-positive bacteria	AurT (M-C) of Staphylococcus aureus
3.A.1.123.3	The one component lantibiotic exporter, GdmT (Sibbald et al., 2006)	Gram-positive bacterium	GdmT (M-C) of Staphylococcus gallinarum (A3QNP2)
3.A.1.124: The 3-component Peptide-5 Exporter (Pep5E) Family
3.A.1.124.1	The 3-component nisin immunity exporter, NisFEG. Contains an essential E-loop (Okuda et al., 2010).	Gram-positive bacteria	NisFEG of Lactococcus lactis NisF (C) NisE (M) NisG (M)
3.A.1.124.2	The 3-component subtilin immunity exporter, SpaEFG	Gram-positive bacteria	SpaEFG of Bacillus subtilis SpaE (M) SpaF (C) SpaG (M)
3.A.1.124.3	The lantibiotic Nukacin ISK-1 (TC# 1.C.21.1.5)/NukH (BAD01013; 92aas) exporter, NukEFG (Okuda et al., 2008)	Gram-positive bacteria	NukEFG of Staphylococcus warneri NukE (M) (Q75V14) NukF (C) (Q75V15) NukG (M) (Q75V13)
3.A.1.124.4	The macedocin exporter, McdEFG (Papadelli et al., 2007)	Gram-positive bacteria	McdEFG of Streptococcus macedonicus McdE (M; 254 aas) (A6MER6) McdG (M; 245 aas) (A6MER7) McdF (C; 304 aas) (A6MER5)
3.A.1.124.5	The salivaricin exporter, SboEFG (Hyink et al., 2007)	Gram-positive bacteria	SboEFG of Streptococcus salivarius SboE (M; 249 aas) (Q09IH9) SboF (C; 303 aas) (Q09II0) SboG (M; 242 aas) (Q09IH8)
3.A.1.125: The Lipoprotein Translocase (LPT) Family
3.A.1.125.1	Lipoprotein translocation system (translocates lipoproteins from the inner membrane to periplasmic chaperone, LolA, which transfers the lipoproteins to an outer membrane receptor, LolB, which anchors the lipoprotein to the outer membrane of the Gram-negative bacterial cell envelope) (see 1.B.46; Narita et al., 2003; Ito et al., 2006; Watanabe et al., 2007). The structure of ligand-bound LolCDE has been solved (Ito et al., 2006). LolC and LolE each have 4 TMSs (1+3). Unlike most ATP binding cassette transporters mediating the transmembrane flux of substrates, the LolCDE complex catalyzes the extrusion of lipoproteins anchored to the outer leaflet of the inner membrane. The LolCDE complex is unusual in that it can be purified as a liganded form, which is an intermediate of the lipoprotein release reaction (Taniguchi and Tokuda, 2008). LolCDE has been reconstituted from separated subunits (Kanamaru et al., 2007).	Gram-negative bacteria	LolCDE of E. coli LolC (M) LolD (C) LolE (M)
3.A.1.125.2	Putative lipoprotein LolCDE homologue LolCE (10TMSs:1+6+3)/LolD	Bacteria	LolCE/LolD of Mycobacterium tuberculosis LolCE (M) (Q7D911) LolD (C) (O53899)
3.A.1.125.3	Duf214 protein (843aas; 10TMSs:1+6+3)	Bacteria	Duf214 protein/ ABC protein of Frankia sp. CcI3: Duf214 protein (M) - Q2J9P4 [LolD/FtsE/SalX]-type ABC protein (C) - Q2J9P5
3.A.1.126: The β-Exotoxin I Exporter (βETE) Family
3.A.1.126.1	Exporter of β-exotoxin I, BerAB	Bacteria	β-exotoxin exporter, BerAB, of Bacillus thuringiensis BerA (C) BerB (M)
3.A.1.127: The AmfS Peptide Exporter (AmfS-E) Family
3.A.1.127.1	Exporter of AmfS extracellular peptidic morphogen (Chater and Horinouchi, 2003; Ueda et al., 2002)	Bacteria	AmfS exporter, AmfAB of Streptomyces griseus AmfA (MC) (BAA33537) AmfB (MC) (BBA33538)
3.A.1.128: The SkfA Peptide Exporter (SkfA-E) Family
3.A.1.128.1	Exporter of SkfA processed peptide (spO31422), SkfEF (González-Pastor et al., 2003)	Bacteria	SkfEF (YbdAB) of Bacillus subtilis SkfE (C) O31427 SkfF (M-M) O31438
3.A.1.128.2	Putative ABC exporter, Teth 514-0346 & 0347	Bacteria	Teth 514-0346 & 0347 of Thermoanaerobacter sp. x514: Teth514-0346 (C) (B0K2P2) Teth514-0347 (M-M) (B0K2P3)
3.A.1.128.3	Putative ABC exporter, CLK2533/CLK2534	Bacteria	CLK2533/CLK2534 of Clostridium botulinum CLK2533 (M-M) (B1L0U0) CLK2534 (C) (B1L0U1)
3.A.1.128.4	Putative ABC exporter Tiet1371/1372	Bacteria	Tiet1371/72 of Thermotoga lettingae Tiet1371 (M-M) (A8F6Z4) Tiet1372 (C) (A8F6Z5)
3.A.1.129: The CydDC Cysteine Exporter (CydDC-E) Family
3.A.1.129.1	Cysteine/Glutathione exporter, CydDC; CydC is also called MdrH (periplasmic cysteine is required for cytochrome bd assembly) (Cruz-Ramos et al., 2004)	Bacteria	CydDC of E. coli CydD (M-C) (P29018) CydC (M-C) (P23886)
3.A.1.130: The Multidrug/Hemolysin Exporter (MHE) Family
3.A.1.130.1	The multidrug/hemolysin exporter, CylA/B (note: CylK (AAF01071) may influence its activity)(Gottschalk et al., 2006)	Bacteria	CylA/B of Streptococcus agalactiae CylA (C) (Q9X432) CylB (M) (Q9X433)
3.A.1.131: The Bacitracin Resistance (Bcr) Family
3.A.1.131.1	The 2 or 3 component bacitracin-resistance efflex pump, BcrAB or BcrABC (Podlesek et al., 1995; Bernard et al., 2003) (BcrA is most similar to SpaF (3.A.1.124.2), but BcrB (5-6 TMSs) is only distantly related to other ABC2-type membrane proteins (Wang et al., 2009). BcrC is not sufficiently similar to detect similarity in BLAST searches. BcrC (5TMSs) belongs to the PAP2 phosphatase superfamily and may not be a contituent of the BcrAB transporter.	Bacteria	BcrABC of Bacillus licheniformis BcrA (C) - (P42332) BcrB (M) - (P42333)
3.A.1.131.2	Lantibiotic immunity system, LanEF. Contains an essential E-loop, a variant of the Q-loop, well conserved in nucleotide binding domains of lantibiotic exporters (Okuda et al., 2010).	Gram-positive bacteria	LanEF of Bacillus licheniformis LanE (M) (Q65DD3) LanF (C) (Q65DD1)
3.A.1.131.3	Transporter homologue, Tiet1372	Bacteria	Tiet1372 of Thermotoga lettingae (A8F6Z5)
3.A.1.132: The Gliding Motility ABC Transporter (Gld) Family
3.A.1.132.1	The GldAFG putative ABC transporter required for ratchet-type gliding motility; may function in secretion of a macromolecule such as an exopolysaccharide. (Agarwal et al., 1997; Hunnicutt et al., 2002; McBride and Zhu 2013). Soluble GldG homologues (no TMSs) are found in eukaryotes (e.g. intraflagellar protein transpoMcBride and Zhu 2013). Soluble GldG homologues (no TMSs) are found in eukaryotes (e.g. intraflagellar protein transporter, IPT52 of Chlamydomonas reinhardtii; XP_001692161)	Bacteria	GldAFG of Flavobacterium johnsoniae: GldA (C; 298 aas) - (O30489) GldF (M; 241 aas; 6TMSs (2+2+2) - (Q93LN1) GldG (M-periplasm; putative auxillary subunit with 2TMSs at the N and C-termini; 561 aas)- (Q93LN0).
3.A.1.132.2	The NosDFY Copper ABC transporter (Chan et al., 1997)	Bacteria	NosDFY of Sinorhizobium meliloti NosD (R; periplasmic copper binding receptor)(Q52899) NosF (C; like GldA) (Q52900) NosY (M; like GldF) (O07330)
3.A.1.132.3	The uncharacterized ABC transporter with GldF-GldG homologues fused	Bacteria	GldAFG homologues of Magnetococcus sp. MC-1 GldFG (M-Aux; 964 aas) (A0L4K8) GldA (C; 399 aas) (A0L4L0)
3.A.1.132.4	The uncharacterized ABC transporter with GldF-GldG homologues fused	Bacteria	GldAFG homologues of Hahella chejuensis GldF-G (M-Aux; 978 aas) (Q2SDB0) GldA (C; 315 aas) (Q2SDB1)
3.A.1.132.5	Putative ABC2 transporter: Membrane protein of 274aas and 6 TMSs; Cytoplasmic ATPase of 302aas.	Proteobacteria	Putative ABC2 transporter of Shewanella pealeana (M) (A8GZV3) (C) (A8GZV2)
3.A.1.132.6	Putative ABC2 transporter: Membrane protein of 274aas and 6 TMSs; Cytoplasmic ATPase of 302aas.	Firmicutes	Putative ABC-2 transporter of Streptococcus pyogenes (M) (Q99ZC7) (C) (Q99ZC8)
3.A.1.132.7	Putative ABC membrane protein with 12 TMSs. (ATPase subunit unknown, and not encoded by an adjacent gene).	Planctomycetes	ABC membrane protein of Rhodopirellula baltica
3.A.1.132.8	ABC transporter, annotated as involved in multi copper protein maturation	Archaea	ABC exporter of Methanocella conradii permease (M) (H8I780) ATPase (C) (H8I779)
3.A.1.133: The Peptide-6 Exporter (Pep6E) Family
3.A.1.133.1	The modified YydF* peptide exporter, YydIJ (Butcher et al., 2007)	Bacteria	YydIJ of Bacillus subtilis: YydI (C) (Q45593) YydJ (M) (Q45592)
3.A.1.133.2	A 6TMS homologue of YydJ (ORF1) of 280aas	Bacteria	ORF1 of Flavobacteria bacterium BBFL7 (Q26C21)
3.A.1.134: The Peptide-7 Exporter (Pep7E) Family
3.A.1.134.1	The lantibiotic, salivericin A exporter, SalXY	Gram-positive bacteria	SalXY of Streptococcus salivarius SalX (C) SalY (M)
3.A.1.134.2	The bacitracin-resistance (putative bacitracin exporter), MbrAB. Participate with BreSR to control its own gene expression (Bernard et al., 2007).	Gram-positive bacteria	MbrAB of Streptococcus mutans MbrA (C) MbrB (M)
3.A.1.134.3	The bacitracin exporter, BceAB (BarAB; YtsCD) (Bernard et al., 2003; Ohki et al., 2003). Functions in both signaling to the two component system, BceRS, and in export of the antimicrobial peptide. Specific regions and residues are invollved in signalling or transport (Kallenberg et al. 2013).	Gram-positive bacteria	BceAB (YtsCD) of Bacillus subtilis BceA (C) CAB15016 BceB (M) CAB15015
3.A.1.134.4	The bacitracin/vancoresmycin (a tetramic acid antibiotic) resistance exporter (Becker et al. 2009) (most like 3.A.1.134.2)	Firmicutes	SPR0812/SPR0813 of Streptococcus pnenmoiae SPR0812 (C) (Q8DQ77) SPR0813 (M) (Q8DQ76)
3.A.1.134.5	The MDR exporter, YvcRS. Possibly linked to regulation by a sensor kinase/response regulator system (YvcQP) (Joseph et al., 2002; Bernard et al., 2007).	Bacteria	YvcRS of Bacillus subtilis YvcR (C) (O06980) YvcR (M) (O06981)
3.A.1.134.6	The cationic peptide/MDR exporter, YxdLM. Possibly linked to a sensor kinase/reponse regulator system (YxdJK) (Joseph et al., 2002; Bernard et al., 2007).	Bacteria	YxdLM of Bacillus subtilis YxdL (C) (P42423) YxdM (M) (P42424)
3.A.1.134.7	The VraFG ABC transporter interacts with GraXSR [GraS, A6QEW9; GraR, A6QEW8] to form a five-component system required for cationic antimicrobial peptide sensing and resistance (Falord et al., 2012).	Bacteria	VraFG/GraXSR of Staphylococcus aureus VraF (A6QEX0) VraG (A6QEX1)
3.A.1.135: The Drug Exporter-4 (DrugE4) Family
3.A.1.135.1	The heterodimeric multidrug exporter, YdaG/YbdA [YdaG most closely resembles LmrA (27% I), but YdbA most closely resembles MsbA (3.A.1.106.1) (29% I).] (Both proteins are ABC half transporters; only the heterodimer is active; ethidium, daunomycin and BCECF-AM are substrates; Lubelski et al., 2004) These proteins have been renamed LmrC and LmrD (Lubelski et al., 2006)	Gram-positive bacteria	YdaG/YdbA of Lactococcus lactis YdaG (M-C) (AAK04408) YdbA (M-C) (AAK04409)
3.A.1.135.2	The heterodimeric putative multidrug exporter, RscA/RscB; probably orthologous to YdaG/YbdA (TC #3.A.1.117.4) [Transcription is activated by stress conditions (heat, acid) and repressed by a 2-component system, CovRS (Dalton et al., 2006)]	Gram-positive bacteria	RscAB of Streptococcus pyogenes RscA (M-C) (568 aas) (Q9A1K5) RscB (M-C) (594 aas) (Q9A1K4)
3.A.1.136: The Uncharacterized ABC-3-type (U-ABC3-1) Family
3.A.1.136.1	Putative ABC3 permease complex U-ABC3-1a (403aas; 4TMSs:1+3)	Bacteria	U-ABC3-1a of Treponema denticola (M) (Q73MJ0)
3.A.1.137: The Uncharacterized ABC-3-type (U-ABC3-2) Family
3.A.1.137.1	Putative ABC-3-type permease complex, ABC3-2a	Archaea	ABC3-2a of Pyrobaculum calidifontis: ABC3-2a (M) (A3MWP2) ABC3-2a (C) (A3MWP1)
3.A.1.138: The Unknown ABC-2-type (ABC2-1) Family
3.A.1.138.1	Unknown ABC-2 transporter complex-1, U-ABC2-TC-1	Archaea	U-ABC2-TC-1 of Picrophilus torridus: U-ABC2-TC-1a (M) (Q6KYW9) U-ABC2-TC-1a (C) (Q6KYW8)
3.A.1.139: The UDP-Glucose Exporter (U-GlcE) Family (UPF0014 Family)
3.A.1.139.1	UDP-glucose exporter, STAR1/STAR2 (sensitive to aluminum rhizotoxicity) (Probable Type I topology) (Huang et al. 2009).	Plants	STAR1/STAR2 of Oryza sativa STAR1 (C) (Q5Z8H2) STAR2 (M) (Q5W7C1)
3.A.1.139.2	The YbbM protein (SwissProt family UDF0014; 7 putative TMSs)	Bacteria	YbbM of E. coli (P77307)
3.A.1.139.3	The uncharacterized ABC exporter, U-ABC-M/C	Bacteria	U-ABCC/U-ABC-M of Spirochaeta africana U-ABC-C (C) (H9UM45) U-ABC-M (M) (H9UM46)
3.A.1.139.4	Plasma membrane ABC exporter, sensitive to aluminum rhizotoxicity 1/2, STAR1/STAR2 (Larsen et al., 2005). Induced in response to aluminum exposure.	Plants	STAR1/2 of Arabidopsis thaliana STAR1 (C) (Q9C9W0) STAR2 (M) (Q9ZUT3)
3.A.1.140: The FtsX/FtsE Septation (FtsX/FtsE) Family
3.A.1.140.1	The FtsX/FtsE ABC transporter (Arends et al., 2009) (FtsX is of the type III topology). FtsEX directly recruits EnvC to the septum via an interaction between EnvC and a periplasmic loop of FtsX. FtsEX variants predicted to be ATPase defective still recruit EnvC to the septum but fail to promote cell separation. Amidase activation via EnvC in the periplasm is regulated by conformational changes in the FtsEX complex mediated by ATP hydrolysis in the cytoplasm. Since FtsE has been reported to interact with FtsZ, amidase activity may be coupled with the contraction of the FtsZ cytoskeletal ring (Yang et al., 2011).	Bacteria	FtsX/FtsE of E. coli FtsX (M) (P0AC31) FtsE (C) (P0A9R7)
3.A.1.141: The Ethyl Viologen Exporter (EVE) Family (DUF990 Family)
3.A.1.141.1	The ethyl (methyl; benzyl) viologen export pump, EvrABC (EvrB and EvrC of 6 TMSs are members of the large DUF990 superfamily (Prosecka et al., 2009); They appear to be of the ABC-2 topological type).	Bacteria	EvrABC of Synechocystis sp. PCC6803 P73329 slr1910, ABC protein (EvrA) P74256 slr1174, membrane protein (EvrB) P74757 slr0610, membrane protein (EvrC)
3.A.1.141.2	ABC transporter of unknown specificity, AbcABC	Bacteria	AbcABC of Thermoanaerobacter tengcongensis AbcA (M) (Q8R6Q6) AbcB (M) (Q8R6Q5) AbcC (C) (Q8R6Q4)
3.A.1.142: The Glycolipid Flippase (G.L.Flippase) Family
3.A.1.142.1	Glycolipid translocase (flippase) Spr1816/Spr1817 (R.Hakenbeck, personal communication)	Firmicutes	Glycolipid flippase, Spr1816/Spr1817, of Streptococcus pneumoniae Spr1816 (M) (Q8DNC0) Spr1817 (C) (Q8DNB9)
3.A.1.143: The Exoprotein Secretion System (EcsAB(C))
3.A.1.143.1	The exoprotein (including α-amylase) secretion system, EcsAB(C) (Leskel� et al., 1999). Also may play roles in sporulation, competence (Leskel� et al., 1996) and transformation using purified DNA (Takeno et al., 2011). An involvement of EcsC in transport is not established, but it is homologous to the C-terminus of the P-type ATPase, 3.A.3.31.2.	Bacteria	EcsAB(C) of Bacillus subtilis EcsA (C) (P55339) EcsB (M) (P55340) EcsC (M) (P55341)
3.A.1.143.2	YthQ (386aas; 8-9 TMSs)/YthP (ATPase; 0 TMSs)	Bacteria	YthPQ (EscAB) of Bacillus amyloliquefaciens EscA (YthP) (G0IP52) EscB (YthQ) (G0IP51)
3.A.1.144: Functionally Uncharacterized ABC2-1 (ABC2-1) Family

3.A.1.144.1	Functionally uncharacterized ABC2 transporter #1.� This system is encoded by two genes that overlap and are therefore probably translationally coupled; they are in the same operon with the genes for 2.A.1.144.2.	Archaea	ABC2 transporter #1 of Methanocella arvoryzae ABC2-1 (M) (Q0W8T3) ABC2-1 (C) (Q0W8T4)
3.A.1.144.2	Functionally uncharacterized ABC2 transporter #2.� This system is encoded by two genes that overlap and are therefore probably translationally coupled; they are in the same operon with the genes for 2.A.1.144.1.	Archaea	ABC2 transporter #2 of Methanocella arvoryzae ABC2-2 (M) (Q0W8T6) ABC2-2 (C) (Q0W8T7)
3.A.1.144.3	Functionally uncharacterized ABC2 transporter #3.	%u03B4-Proteobacteria	ABC2 transporter of Myxococcus xanthus ABC2-3 (M) (Q1D0V0) ABC2-3 (C) (Q1D0V1)�
3.A.1.144.4	Functionally uncharacterized ABC2 transporter #4.� The membrane protein is triplicated and of 751aas with 18 putative TMSs.	Chloroflexi	ABC2 transporter of Oscillochloris trichoides ABC2 (M) (E1IBA3) ABC2 (C) (E1IBA4)
3.A.1.145: Peptidase Fused Functionally Uncharacterized ABC2-2 (ABC2-2) Family
3.A.1.145.1	ABC2 transporter domain fused to an aminopeptidase N domain (Peptidase M1 family) of 1200 aas with 13 putative N-terminal TMSs.	δ-proteobacteria	ABC2 protein of Myxococcus xanthus
3.A.1.145.2	Putative ABC2 permease of 529 aas and 12 TMSs, Glr0437.	Cyanobacteria	Glr0437 of Gloeobacter violaceus
3.A.1.145.3	ABC2 fusion protein of 1194 aas and 13 putative TMSs.� Annotated as ABC transporter involved in multi-copper enzyme maturation; permease component.	Bacteroidetes	ABC2 protein of Cecembia lonarensis
3.A.1.145.4	Putative ABC2 protein of 537 aas and 14 putative TMSs	Archaea	ABC2 permease of Methanocella paludicola
3.A.1.201: The Multidrug Resistance Exporter (MDR) Family (ABCB)
3.A.1.201.1	Broad specificity multidrug resistance (MDR1; ABCB1; P-glycoprotein) efflux pump (exports organic cations and amphiphilic compounds of unrelated chemical structure) (These include: anti-biotics, viral agents, cancer agents, hypertensives, depressants, histamines, emetics, and the protease inhibitor, lopinavir. Pgp also exports immunosuppressants, detergents, long-chain fatty acids, HIV protease inhibitors, synthetic tetramethylrosamine analogues, calcein M, etc.); peptide efflux pump; phospholipid (e.g., phosphatidyl serine), cholesterol and sterol flippase (also called ABCB1 and p-gp)). Binds and probably transports inhibitors and agonists of SUR (2.A.1.208.4) (Bessadok et al., 2011). The 3-d structure has been determined (Aller et al., 2009). It can pump from the cytoplasmic leaflet to either the outer leaflet or the outer medium (Katzir et al., 2010). The inhibitor, 5''-fluorosulfonylbenzoyl 5''-adenosine, an ATP analogue, interacts with both drug-substrate- and nucleotide-binding sites (Ohnuma et al., 2011). Inhibited by Sildenafil (Shi et al., 2011) and lapatinib derivatives (Sodani et al., 2012). HG-829 is a potent non-competitive inhibitor (Caceres et al., 2012). Berberine, palmatine, jateorhizine and coptisine are all P-gp substrates, and cyclosporin A and verapamil are inhibitors (Zhang et al., 2011). Transports clarithromycin (CAM), a macrolide antibiotic used to treat lung infections, more effectively than azithromycin (AZM) or telithromycin (TEL) (Togami et al. 2012). Nucleotides, lipids and drugs bind synergistically to the pump (Marcoux et al. 2013).	Animals, fungi, bacteria	MDR1 of Homo sapiens
3.A.1.201.2	Bile salt export pump, BSEP or SPGP (associated with progressive familial intrahepatic cholestasis-2 (also called ABCB11) and benign recurrent intrahepatic cholestasis (Kagawa et al., 2008)). Unconjugaged bile salts and glycine conjugates > taurine conjugates. BSEP mediates biliary excretion of bile acids from hepatocytes. Compounds based on GW4064 (Q96RI1), a representative farnesoid X receptor (RXR) agonist, enhance E297G BSEP transport activity (Misawa et al., 2012).	Animals	BSEP of Homo sapiens
3.A.1.201.3	Short chain fatty acid phosphatidylcholine translocase (phospholipid flippase), MDR3 (associated with progressive familial intrahepatic cholestasis 3 and progressive intrafamilial hepatic disease (Quazi and Molday, 2011)). (Narrow drug specificity relative to MDR1. Exports digoxin, paclitaxel, vinblastin and bile acids.) (also called ABCB4). ABCB4 regulates phosphatidylcholine secretion into bile and its translocation across the plasma membrane in hepatocytes (Voloshyna and Reiss, 2011).	Animals	MDR3 of Homo sapiens
3.A.1.201.4	The multidrug resistance/chloroquine resistance protein, Pfmdr1	Protozoa	Pfmdr1 of Plasmodium falciparum (P13568)
3.A.1.201.5	Auxin efflux pump Pgp1 (MDR1; ABCB1) (Carraro et al. 2012). Regulated by Twd1, an FK506-binding protein immunophilin prolyl/peptidyl isomerase; 8.A.11.1.1 (Bouchard et al., 2006). Involved in light-dependent hypocotyl elongation (Sidler et al. 1998).	Plants	Pgp1 of Arabidopsis thaliana (Q9ZR72)
3.A.1.201.6	Auxin efflux pump Pgp19 (MDR11) (regulated by Twd1, an FK506-binding protein immunophilin prolyl/peptidyl isomerase; 8.A.11.1.1 (Bouchard et al., 2006))	Plants	Pgp19 of Arabidopsis thaliana (Q9LJX2)
3.A.1.201.7	Auxin efflux pump Pgp4; functions in the basipetal redirection of auxin from the root tip. Strongly expressed in root cap and epidermal cells (Terasaka et al., 2005)	Plants	Pgp4 of Arabidopsis thaliana (MCMC) O80725
3.A.1.201.8	The aluminum chelate (aluminum sensitivity (ALS1)) protein; expressed in root vacuoles half-type ABC transporter (not induced by aluminum; Larsen et al., 2007).	Plants	ALS1 (M-C) of Arabidopsis thaliana (Q0WML0)
3.A.1.201.9	Marine skate liver bile salt exporter, BSEP (1348 aas) (transports taurocholine in an ATP-dependent fashion (Cai et al., 2001)) (Most similar to 3.A.1.201.2)	Animals	BSEP of Raja erinacea (MC MC) (Q90Z35)
3.A.1.201.10	Mdr1; resistance to Cilofungin and other drugs (Lamping et al., 2010)	Fungi	Mdr1 (MCMC) of Aspergillus fumigatus (B0Y3B6)
3.A.1.201.11	Mdr1 azole resistance efflux pump (Lamping et al., 2010)	Fungi	Mdr1 (MCMC) of Cryptococcus (Filobasidiella) neoformans (O43140)
3.A.1.201.12	California mussel ABCB/MDR multixenobiotic resistance efflux pump (Luckenbach and Epel, 2008).	Animals	ABCB/MDR transporter of Mytilus californianus (MCMC) (B2WTH9)
3.A.1.201.13	Plasma membrane AbcB5. Mediates resistance of tumor cells to doxorubicin and other drugs. Catalyzes efflux of rhodamine.	Animals	AbcB5 of Homo sapiens (Q2M3G0)
3.A.1.201.14	P-glycoprotein-1 MDR exporter. Transports multiple drugs, cancer chemotherapy agents, cancer unrelated compounds and many xenobiotics. The crystal structure at 3.4 A resolution is available (Jin et al. 2012). It has 4,000x higher affinity for actinomycin D in the membrane bilayers than in detergent. A "ball and socket joint" and salt bridges similar to ABC importers suggested that both types of systems, importers and exporters, use the same mechanism to interconnect ATP hydrolysis with transport and achieve alternating access of the substrate binding site to the two sides of the membrane.	Animals	P-glycoprotein-1 of Caenorhabditis elegans
3.A.1.201.15	MDR efflux pump, ABCB1a. Exports canonical MDR susbtrates such as calcein-AM, bodipy-verapamil, bodipy-vinblastine and mitoxantrone (Gokirmak et al. 2012).	Animals	ABCB1a of Stronglycentrotus purpuratus
3.A.1.201.16	MDR efflux pump, ABCB4a. Exports canonical MDR susbtrates such as calcein-AM, bodipy-verapamil, bodipy-vinblastine and mitoxantrone (Gokirmak et al. 2012).	Animals	ABCB4a of Stronglycentrotus purpuratus
3.A.1.201.17	Miltochondrial ABCB10 transporter. Essential for erythropoiesis, and for protection of mitochondria against oxidative stress. The 3-d structures of several conformations are available (3ZDQ; Shintre et al. 2013).	Animals	ABCB10 of Homo sapiens
3.A.1.202: The Cystic Fibrosis Transmembrane Conductance Exporter (CFTR) Family (ABCC)
3.A.1.202.1	Cystic fibrosis transmembrane conductance regulator (CFTR) (also called ABCC7); cyclic AMP-dependent chloride channel; also catalyzes nucleotide (ATP-ADP)-dependent glutathione and glutathione-conjugate flux (Kogan et al., 2003) (may also activate inward rectifying K⁺ channels). The underlying mechanism by which ATP hydrolysis controls channel opening is described by Gadsby et al., 2006. The most common cause of cystic fibrosis (CF) is defective folding of a cystic fibrosis transmembrane conductance regulator (CFTR) mutant lacking Phe508 (DeltaF508)(Riordan, 2008). The DeltaF508 protein appears to be trapped in a prefolded state with incomplete packing of the transmembrane segments, a defect that can be repaired by direct interaction with correctors such as corr-4a, VRT-325, and VRT-532 (Wang et al., 2007). CFTR interacts directly with MRP4 (3.A.1.208.7) to control Cl^- secretion (Li et al., 2007). It has intrinsic adenylate kinase activity that may be of functional importance (Randak and Welsh, 2007). The intact CFTR protein mediates ATPase rather than adenylate kinase activity (Ramjeesingh et al., 2008). Regulated by Na⁺/H⁺ exchange regulatory cofactors (NHERF; O14745; TC #8.A.24.1.1) (Seidler et al., 2009). Regulated by protein kinase A and C phosphorylation (Csanády et al., 2010). It is also activated by membrane stretch induced by negative pressures (Zhang et al., 2010). TMS6 plays roles in gating and permeation (Bai et al., 2010; 2011). The 3-D structure revealed the probable location of the channel gate (Rosenberg et al., 2011). Conformational changes opening the CFTR chloride channel pore, coupled to ATP-dependent gating, have been studied (Wang and Linsdell, 2012). Alternating access to the transmembrane domain of CFTR has been demonstrated (Wang and Linsdell, 2012). MRP4 and CFTR function in the regulation of cAMP and beta-adrenergic contraction in cardiac myocytes (Sellers et al., 2012). An asymmetric hourglass, comprising a shallow outward-facing vestibule that tapers toward a narrow "bottleneck" linking the outer vestibule to a large inner cavity extending toward the cytoplasmic extent of the lipid bilayer has been proposed (Norimatsu et al., 2012).	Animals	CFTR of Homo sapiens
3.A.1.203: The Peroxysomal Fatty Acyl CoA Transporter (P-FAT) Family (ABCD)
3.A.1.203.1	Peroxysomal long chain fatty acyl (LCFA) transporter associated with Zellweger Syndrome	Animals	PMP70 of Homo sapiens
3.A.1.203.2	Peroxysomal long chain fatty acyl (LCFA) Coenzyme A import porter	Yeast	Pat1 (758-870 aas; 5 TMSs)/Pat2 (853 aas; 4 TMSs) of Saccharomyces cerevisiae
3.A.1.203.3	The peroxysomal long chain fatty acid (LCFA) half transporter, ABCD1 (ALD, the adrenoleukodystrophy protein) (functions as a homodimer and accepts acyl-CoA esters (van Roermund et al. 2008)). Transports C24:0 and C26:0 as substrates (van Roermund et al., 2011).� ABCD1 deficiency is associated with plasma and tissue elevation of C24:0 and C26:0 accompanied by demyelination and inflamation (Baarine et al. 2012).	Animals	LCFA transporter of Homo sapiens
3.A.1.203.4	The BacA (Rv1819c) porter (selective for the uptake of bleomycin and antimicrobial peptides) (essential for maintenance of extended chronic infection) (Domenech et al., 2009).	Actinobacteria	BacA of Mycobacterium tuberculosis (M-C) (Q50614)
3.A.1.203.5	Peroxisomal importer, Comatose, of substrates for β-oxidation (transports precursors 2,4-dichlorophenoxybutyric acid (2,4-DB) and indole butyric acid (IBA) (Dietrich et al., 2009). The peroxisomal fatty acyl-CoA transporter, Comatose (CTS ABCD1); (CTS, nBCD1; 1337aas) (Nyathi et al., 2010) determines germination potential and fertility and is essential for acetate metabolism (Linka and Esser 2012).	Plants	Comatose of Arabidopsis thaliana (Q94FB9)
3.A.1.203.6	Peroxisomal long-chain fatty acid importer, PXA1/PXA2 (Lamping et al., 2010; van Roermund et al., 2011)	Yeast	PXA1/PXA2 of Saccharomyces cerevisiae PXA1 (MC) (P41909) PXA2 (MC) (P34230)
3.A.1.203.7	Peroxisomal fatty acid transporter, ABCD2 or ALDRP. Transports C22:0 and different unsaturated very long-chain fatty acids including C24:6 and especially C22:6 (van Roermund et al., 2011).	Animals	ABCD2 (M-C) of Homo sapiens (Q9UBJ2)
3.A.1.203.8	Peroxisomal/chloroplast fatty acyl CoA transporter, ABCD2 (Linka and Esser 2012).	Plants	ABCD2 of Arabidopsis thaliana
3.A.1.204: The Eye Pigment Precursor Transporter (EPP) Family (ABCG)
3.A.1.204.1	Eye pigment precursor transporter	Animals, yeast	White of Drosophila melanogaster
3.A.1.204.2	Drug resistance transporter, ABCG2 (MXR; ABCP) (human breast cancer resistance protein) (Moitra et al., 2011). It exports haem in haempoietic cells (Latunde-Dada et al., 2006) as well as cytotoxic agents (mitoxantrone, flavopiridol, methotrexate, 7-hydroxymethotrexate, methotrexate diglutamate, topotecan, and resveratrol), fluorescent dyes (Hoechst 33342) and other toxic substances (PhIP and pheophorbide a) (Özvegy-Laczka et al., 2005). It also transports folate and sterols: estradiol, and probably cholesterol, progesterone, testosterone and tamoxifen (Janvilisri et al., 2003; Breedveld et al., 2007). It is a homotetramer (Xu et al., 2004). It forms a homodimer bound via a disulfide bond at Cys-603 which stabilizes the protein against ubiquitin-mediated degradation in proteosomes (Wakabayashi et al., 2007). It has 6 established TMSs with the N- and C- termini inside (Wang et al., 2008). Also called breast cancer resistance protein, BCRP (ABCG) (MDR pump) (exports from human breast cancer cell line MCF-7: miloxantrone, daunorubicin, doxorubicin and rhodamine123). Also transports reduced folates as well as mono-, di- and tri-glutamate derivatives of folic acid and methotrexate (Assaraf et al., 2006). It is an active glutathione efflux pump (Brechbuhl et al., 2010). Mutations in ABCG2 cause hyperuricemia and gout , which has led to the identification of urate as a physiological subsrate for ABCG2. Zafirlukast antagonizes ATP-binding cassette subfamily G member 2-mediated multidrug resistance (Sun et al., 2012). Inhibited by Sildenafil (Shi et al., 2011) and lapatinib derivatives (Sodani et al., 2012).	Animals, yeast	ABCG2 (ABCP) of Homo sapiens (Q9UNQ0)
3.A.1.204.3	Putative ABC Transporter WHT-1	Worm	WHT-1 of Caenorhabditis elegans (Q11180)
3.A.1.204.4	The plant cuticular wax exporter, CER5 (in the plasma membrane of epidermal cells; secretes wax to the plant surface) (Pighin et al., 2004)	Plants	CER5 (C-M) of Arabidopsis thaliana (AAU44368)
3.A.1.204.5	The ABCG5 (sterolin-1)/ABCG8 (sterolin-2) heterodimeric neutral sterol (cholesterol and plant sterols) (e.g., sitosterol) (phosphoryl donors ATP > CTP > GTP > UTP) exporter; present in the apical membranes of enterocytes and hepatocytes. Cholesteryl oleate, phosphatidyl choline and enantiomeric cholesterol are poorly transported (mutation of either ABCG5 or ABCG8 cause sitosterolemia and coronary atherosclerosis) (Zhang et al., 2006; Wang et al., 2006; 2011). Involved in cell signalling, creation of membrane asymmetry and apoptosis (Quazi and Molday, 2011).	Animals	ABCG5/ABCG8 of Homo sapiens ABCG5 (Q9H222) ABCG8 (Q9H221)
3.A.1.204.6	The efflux porter for phosphatidylcholine and its analogues as well as toxic alkyl phospholipids, ABCG4 (Castanys-Munoz et al., 2007). Also promotes cholesterol efflux to the mature forms of HDL (HDL2 and HDL3) (Voloshyna and Reiss, 2011).	Protozoa	ABCG4 of Leishmania infantum (A4HWI7)
3.A.1.204.7	Multidrug resistance efflux pump, AbcG6, causes camptothecin-resistant parasites (Bosedasgupta et al., 2008)	Euglenozoa	AbcG6 of Leishmania donovani (A8WEV1)
3.A.1.204.8	The epidermal plasma membrane cuticular lipid (wax) exporter, ABCG11 (wbc11); may interact with CER5 (Bird et al., 2007).	Plants	ABCG11 of Arabidopsis thaliana (Q8RXN0)
3.A.1.204.9	The putative multidrug/pigment exporter, Adp1 (Lamping et al., 2010)	Yeast	Adp1 (C-M) of Saccharomyces cerevisiae (P25371)
3.A.1.204.10	AbcH homologue	Animals	AbcH homologue of Caernorhabditis elegans (Q18900)
3.A.1.204.11	AbcG Homologue	Plants	AbcG of Physcomitrella patens (A9SCA8)
3.A.1.204.12	The intracellular sterol transporter, ABCG1 (Tarling and Edwards, 2011).�Involved in cell signalling, creation of membrane asymmetry and apoptosis (Quazi and Molday, 2011). Promotes cholesterol efflux from macrophages to the mature forms of HDL (HDL2 and HDL3) (Voloshyna and Reiss, 2011).� Plays a role in arteriosclerosis (M�nch et al. 2012).� The diverse functions invarious cell types have been reviewed by Tarling (2013).� Many mammals have two isoforms, long and short, but mice have only the short isoform (Burns et al. 2013).	Animals	ABCG1 of Homo sapiens (P45844)
3.A.1.204.13	The ABCG1 transporter homologue	Slime Molds	ABCG1 of Dictyostelium discoideum (Q55DW4)
3.A.1.204.14	ABC transporter-like protein ECU11_1340	Fungi	ECU11_1340 of Encephalitozoon cuniculi
3.A.1.204.15	MDR efflux pump, ABCG2a. Exports canonical MDR susbtrates such as calcein-AM, bodipy-verapamil, bodipy-vinblastine and mitoxantrone (Gokirmak et al. 2012).	Animals	ABCG2a of Stronglycentrotus purpuratus
3.A.1.204.16	Half ABC transporter, ABCG10. Secretes isoflavinoids including precursors of the phytoalexin, medicarpin (Banasiak et al. 2013).	Plants	ABCG10 of Medicago truncatula
3.A.1.205: The Pleiotropic Drug Resistance (PDR) Family (ABCG)
3.A.1.205.1	Pleiotropic drug resistance (PDR) exporter; steroid exporter; sporidesmin toxicity suppressor (Sts1); MDR; cyclic nucleotide exporter; amphipathic anion exporter. Its ATPase activity is inhibited by its substrate, clotrimazole; can use ATP, GTP and maybe UTP to drive efflux (Golin et al., 2007). Molecular modeling revealed aspects of the binding pocket and mechanism of action (Rutledge et al. 2011).	Yeast	Pdr5 (Sts1; Ydr1) (C-M-C-M) of Saccharomyces cerevisiae (P33302)
3.A.1.205.2	Drug/Sterol/Mutagen exporter, Snq2p	Yeast	Snq2p of Saccharomyces cerevisiae (P32568)
3.A.1.205.3	Weak acid exporter, Pdr12p (exports preservative anions including propionate, sorbate and benzoate) (Mollapour et al., 2008)	Yeast	Pdr12p of Saccharomyces cerevisiae (Q02785)
3.A.1.205.4	Multidrug resistance protein, Cdr1 (confers resistance to cycloheximide and antifungal agents such as azoles and terbinafine) (Holmes et al., 2006; Schuetzer-Muehlbauer et al., 2003); also, transports phospholipids (Shukla et al., 2007). It is the major fluconazole efflux system in fluconazole-resistant C. albicans (Holmes et al., 2008; Basso et al., 2010). Similar to Cdr2. For additional details of both systems, as well as other MDR pumps in various Candida species, see (Cannon et al., 1998). Chimeras between Cdr1 an Cdr2 revealed regions determining substrate specificity (Tanabe et al., 2011).	Yeast	Cdr1 (C-M-C-M) of Candida albicans (P43071)
3.A.1.205.5	Multidrug resistance protein, Cdr2 (confers resistance to azole and other antifungal agents/terbinafine, amorolfine, aspofungin, etc. as well as a variety of metabolic inhibitors) (Schuetzer-Muehlbauer et al., 2003; Basso et al., 2010). Chimeras between Cdr1 an Cdr2 revealed regions determining substrate specificity (Tanabe et al., 2011). Has an external binding site for an inhibiting octapeptide derivative (Niimi et al., 2012).	Yeast	Cdr2 of Candida albicans (P78595)
3.A.1.205.6	Multidrug resistance protein, Cn Afr1 (confers resistance to azole antifungal drugs including fluconazole) (Posteraro et al., 2003)	Fungi	CnAFR1 (C-M-C-M) of Cryptococcus neoformans (Q8X0Z3)
3.A.1.205.7	The multidrug resistance protein, AtrB (confers resistance to all major classes of fungicides as well as natural toxic compounds substrates include: anilinopyrimidine, benzimidazole, phenylpyrrole, phenylpyridylamine, strobirulin, azoles, dicarboximides, quintozene, acriflavin, and rhodamine 6G as well as natural toxins such as camptothecin (an alkaloid) and the stilbene phytoalexin, resveratrol) (Andrade et al., 2000).	Fungi	AtrB of Aspergillus nidulans (P78577)
3.A.1.205.8	The multidrug resistance protein, Pdr11p, mediates sterol uptake by promoting movement of sterols from the plasma membrane to the endoplasmic reticulum where esterification occurs (Li and Prinz, 2004).	Yeast	Pdr11p of Saccharomyces cerevisiae (P40550)
3.A.1.205.9	The plasma membrane Cd²⁺/Pb²⁺ efflux pump (heavy metal resistance pump), PDR8, present in root hair and epidermal cells; it may export a broad range of substrates (Kim et al., 2007). Also reported to transport flavenoid glycosides (phytoalexins) as well as quercitin, kaempeferol and salicylate (Badri et al. 2012).	Plants	PDR8 of Arabidopsis thaliana (Q9XIE2)
3.A.1.205.10	Pleiotropic drug resistance (PDR) exporter, PDR12 (function as a pump to exclude Pb²⁺ ions and/or Pb²⁺- containing toxin compounds) (Lee et al., 2005)	Plants	PDR12 of Arabidopsis thaliana (Q9M9E1)
3.A.1.205.11	The brefeldin resistance protein, Bfr1, (also exports actinomycin D, cerulenin, and cytochalasin B) (Turi and Rose, 1995; Nagao et al., 1995).	Yeast	Bfr1 of Schizosaccharomyces pombe (P41820)
3.A.1.205.12	The plasma membrane Pdr10, a negative regulator for incorporation of Pdr12 (TC# 3.A.1.205.3) into detergent-resistant membranes, a novel role for members of the ABC transporter superfamily (Rockwell et al., 2009) (most like 3.A.1.205.1; 67% identity).	Yeast	PDR10 of Saccharomyces cerevisiae (P51533)
3.A.1.205.13	The putative sterol uptake transporter, Aus1 (also protects against antifungal azoles such as fluconazole and itraconazole; (Nakayama et al., 2007).	Yeast	Aus1 of Candida glabrata (Q6FUR1)
3.A.1.205.15	Anaerobically-induced AusI. Specifically stimulated by phosphatidylserine in proteoliposomes. May translocate cholestrol and derivatives (Marek et al., 2011).	Yeast	AusI of Saccharomyces cerevisiae (Q08409)
3.A.1.205.16	ABCG32/PEC1 transporter. Required for plant cuticle production (Bessire et al. 2011).	Plants	ABCG32/PEC1 of Arabidopsis thaliana
3.A.1.205.17	ABC transporter, PDR1. Secretes phytohormones such as strigolactones that regulate plant shoot architecture and stimulate germination (Kretzschmar et al. 2012).	Plants	PDR1 of Petunia hybrida
3.A.1.205.18	The monolignol (p-coumaryl alcohol) transporter, ABCG29. May also transport various phenolic compounds and glucosinolates (Alejandro et al. 2012). Reported to be required for normal meiotic double strand DNA break formation resulting from interaction with SPO11-1 (De Muyt et al. 2007).	Plants	ABCG29 of Arabidopsis thaliana
3.A.1.205.19	Small molecule transporter, ABCG10. Poorly expressed in an lrrB mutant (Sugden et al. 2010).	Slime molds	ABCG10 of Dictyostelium discoideum
3.A.1.205.20	TUR2 transporter. May be a general defense protein. Involved in turion (dormant buds) formation. Confers resistance to the diterpenoid antifungal agent sclareol (van den Brûle et al. 2002). Induced by abiotic stresses such as cold-stress, cycloheximide and sodium chloride (NaCl). Induction by abscisic acid (ABA) is repressed by cytokinin such as kinetin (Crouzet et al. 2006).	Plants (Aquaphytes)	TUR2 of Spirodela polyrrhiza
3.A.1.205.21	ABC1 transporter. Excretes secondary metabolites such as terpenes. Involved in both constitutive and jasmonic acid-dependent induced defense. Confers some resistance to sclareol and B.cinerea (Stukkens et al. 2005). Induced by terpenes such as sclareolide and sclareol, and by some phytohormones such as jasmonic acid (JA) and ethylene. Strongly induced by compatible pathogens such as the fungus B. cinerea, and the bacteria P. syringae pv tabaci, as well as by non pathogenic bacteria such as P. fluorescens, and P. marginalis pv marginalis (Grec et al. 2003).	Plants	ABC1 of Nicotiana plumbaginifolia
3.A.1.206: The a-Factor Sex Pheromone Exporter (STE) Family (ABCB)
3.A.1.206.1	a-Factor sex pheromone (a hydrophobic isoprenylated (farnesylated) carboxymethylated peptide) exporter, Ste6 (Michaelis and Barrowman 2012).	Yeast	Ste6 of Saccharomyces cerevisiae
3.A.1.207: The Eukaryotic ABC3 (E-ABC3) Family
(functions unknown; ABC-type ATPases have not been identified.)
3.A.1.207.1	The hypothetical protein, HP (1209aas; 10TMSs:1+6+3; 2-4 are homologous to 8-10; the FtsX domain) (P. tetraurelia has at least 5 paralogues.)	Ciliates	HP of Paramecium tetraurelia (M) (A0ECD9)
3.A.1.207.2	Putative permeases; Duf214 protein (1234aas; 10TMSs: 1+6+3; 2-4 are homologous to 8-10 (the FtsX domain))	Ciliates	Putative permease of Tetrahymena thermophila (M) (Q22NS1)
3.A.1.207.3	Hypothetical protein, HP (1465aas; 8TMSs:1+6+1) (D. discoideum has several paralogues)	Slime mold	HP of Dictyostelium discoideum (M) - Q8ST07
3.A.1.207.4	Hypothetical protein, HP, 1129aas (homologous are found in many unicellular eukaryotes)	Amoeba	HP of Entamoeba histolytica (M) (C4LT38)
3.A.1.208: The Drug Conjugate Transporter (DCT) Family (ABCC) (Dębska et al., 2011)
Dębska et al., 2011
3.A.1.208.1	Multi-drug resistance-associated protein, MRP1-like protein (MLP1 or MRP1) (Exporter of leukotrienes, glutathione and cysteinyl conjugates of organic anions, drugs, unmodified hydrophobic xenobiotics and hydrophilic conjugated endobiotics). Vincristine and glutathione are co-transported. MRP1 catalyzes export of glutathione during apoptosis (Hammond et al., 2007). Also transports reduced folates as well as mono-, di- and tri-glutamate derivatives of folic acid and methotrexate (Assaraf et al., 2006).	Animals	MRP1 of Rattus norvegicus (O88269)
3.A.1.208.2	Hepatic canalicular conjugate exporter (the Dubin-Johnson Syndrome protein) (transports bilirubin glucuronides; E₂ 17 β glucuronide, dianionic bile salts such as taurocholate, taurochenodeoxycholate sulfate and taurolithocholate sulfate; reduced glutathione; glutathione conjugates; glucuronides; cysteinyl leukotrienes; arsenic-glutathione complexes and glutathione disulfide; also exports anthracyclines, epipodophyllotosine, Vinca alkaloids, cisplatin, methotrexate, and the protease inhibitor, lopinavir) (also called ABCC2) (Chen and Tiwari, 2011; Krumpochova et al., 2012). MK-571 is an inhibitor (Zhang et al., 2011).	Animals	cMRP (MRP2; cMOAT) of Homo sapiens (Q92887)
3.A.1.208.3	Oligomycin-resistance protein YOR1 in plasma membrane (confers resistance to oligomycin, rhodamine B, tetracycline, verapamil, eosin Y and ethidium bromide; Grigoras et al., 2007)).	Yeast	YOR1 (M-C-M-C) of Saccharomyces cerevisiae (P53049)
3.A.1.208.4	SUR1 sulfonylurea receptor; subunit and regulator of α-cell ATP-sensitive K⁺ channel (TC #1.A.2); determines ATP sensitivity; no inherent transport function known; associated with persistent hyperinsulinemic hypoglycemia of infancy due to focal adenomatous hyperplasia (also called ABCC8). Gain-of-function mutations in the genes encoding the ATP-sensitive potassium (K(ATP)) channel subunits Kir6.2 (KCNJ11) and SUR1 (ABCC8) cause neonatal diabetes mellitus. Because mutant channels are inhibited less strongly by MgATP, this increases K(ATP) currents in pancreatic beta cells, thus reducing insulin secretion and producing diabetes (de Wet et al., 2007). Binds ligands (blockers): glibenclamide, tolbutamide, and meglitinide as well as agonists, SR47063 (a cromakalim analog), P1075 (a pinacidil analog), and diazoxide (Bessadok et al., 2011). ATP activates ATP-sensitive potassium channels composed of mutant sulfonylurea receptor 1 and Kir6.2 with diminished PIP2 sensitivity (Pratt and Shyng, 2011). Dominant missense mutations in ABCC9, promoting open channel formation, cause Cantú syndrome (Harakalova et al., 2012; van Bon et al., 2012). The N-terminal transmembrane domain of SUR1 controls gating of Kir6.2 by modulating channel sensitivity to PIP2 (Pratt et al., 2011). Familial mild hyperglycemia is due to the ABCC8-V84I mutation (Gonsorcikova et al., 2011). ATP regulates KATP channels by promoting dimerization and conformational switching (Ortiz et al. 2013).	Animals	SUR1 of Homo sapiens (Q09428)
3.A.1.208.5	Vacuolar multidrug resistance efflux pump, AtMRP2 (catalyzes vacuolar uptake of glutathione conjugates (i.e., 2,4-dinitrophenyl-GS), glucuronide conjugates (i.e., 17 β-estradiol 17(β-D-glucuronide), and reduced glutathione). Also exports the herbicide, 1-chloro-2, 4-dinitrobenzene, and chlorophyll degradation catabolites (Frelet-Barrand et al., 2008).	Plants	AtMRP2 of Arabidopsis thaliana (O64590)
3.A.1.208.6	Metal-thiol conjugate exporter, PgpA; glutathione and trypanothione conjugates are exported; confers arsenite and antimonite resistance (trypanothione is glutathione-spermidine).	Protozoa	PgpA of Leishmania tarentolae (P21441)
3.A.1.208.7	MRP4 (exporter of cyclic nucleotides (cAMP, cGMP)and other nucleotide analogues), purine analogues, methotrexate, bile acids, prostaglandins E1 and E2, reduced folates, 9(2-phosphonylmethyoxyethyl)adenine, leukotrienes, estradiol 17-β-D-glucuronide) and drug sulfate conjugates (inhibited by nonsteroidal antiinflammatory drugs (Reid et al., 2003; Rius et al., 2008)). When overexpressed, it can lower the intracellular concentration of nucleoside/nucleotide analogs, such as the antiviral compounds PMEA (9-(2-phosphonylmethoxyethyl)adenine) or ganciclovir, and of anticancer nucleobase analogs, such as 6-mercaptopurine, after their conversion into the respective nucleotides. MRP4 interacts directly with CFTR (3.A.1.202.1) to control Cl^- secretion (Li et al., 2007). Thus, MRP4 is a broad specificity organic anion exporter (Ritter et al., 2005). MRP4 and CFTR function in the regulation of cAMP and beta-adrenergic contraction in cardiac myocytes (Sellers et al., 2012).	Animals	MRP4 (MOAT-B) of Homo sapiens (O15439)
3.A.1.208.8	Drug resistance pump; ABCC1 (MRP1), exports chemotherapeutic agents, organic anions such as leukotriene C₄ (LTC₄), 17-β-estradiol 17-β-D-glucuronide, glucuronide-X (E₂17βG, etoposide-glucuronide), estrone-3-sulfate, folic acid and methotrexate, arsenic triglutathione, arsenic and antimonial oxyanians, glutathione (GSH), GSSG, glutathione conjugates (GSH-X; LTC₄, DNP-SG, EA-SG, NEH-SG), sulfate-X (E₁S, DHEAS), HIV protease inhibitors, anthracyclines, epipodophyllotoxins, and Vinca alkaloids. Changing charged residues in TMS6 (K332, H335 and D336) gave rise to specific changes in specificity (Chen et al., 2006; Haimeur et al., 2002; Leslie et al., 2004). Also exports cobalamine (Vitamin B₁₂) (Beedholm-Ebsen et al., 2010). Also exports cytotoxic metals including antimony, mercuric ions, arsenate and arsenite, but not copper, chromium, cobalt and aluminum, often as glutathione conjugates (Aleo et al., 2005 ; Vernhet et al., 2000). Notch1 regulates the expression in cultured cancer cells (Cho et al., 2011). Structural and functional properties of MRP1 have been reviewed comprehensively (He et al. 2011).	Animals	MRP1 of Homo sapiens (P33527)
3.A.1.208.9	Canicular multispecific organic anion transporter, MRP3 (also called ABCC3) (most similar in sequence to MRP2). MRP3 exports epipodophyllotoxins, etoposide and teniposide, estradiol 17-β-D-glucuronide, leukotriene C₄, dinitrophenyl S-glutathione, epoposide glucuronide, methotrexate, bilirubin-glucuronides, bile acids, GSH-X (LTC₄, DNP-SG) and sulfate-X (taurolithocholate-3-sulfate). Substrate translocation and stimulated ATP hydrolysis show positive cooperativity (Hill coefficient = 2) and are half-coupled (Seelheim et al. 2012).	Animals	MRP3 of Homo sapiens (O15438)
3.A.1.208.10	Multidrug (anthracycline) resistance organic anion efflux pump (ABC-C6; MRP6; MOAT-E - the pseudoxanthoma elasticum disease protein) exports glutathione conjugates including lencotriene C₄, DNP, and N-ethylmaleimide S-glutathione; also exports anthracyclines, epipodophyllotoxins, cisplatin, and probably exports probenecid, benzbromarone and indomethacin (Chen and Tiwari, 2011).	Animals	ABCC6 (MRP6) of Homo sapiens (O95255)
3.A.1.208.11	Vacuolar metal resistance and drug detoxification protein, yeast cadmium factor (YCF1); transports cadmium-glutathione conjugates, glutathione S-conjugated leucotriene C₄, organic glutathione S-conjugates, selenodigluthatione, unconjugated bilirubin, reduced glutathione, and diazaborine (Lazard et al., 2011).	Yeast	YCF1 of Saccharomyces cerevisiae (P39109)
3.A.1.208.12	Bile acid transporter, BAT1 (in vacuoles)	Yeast	BAT1 of Saccharomyces cerevisiae (P32386)
3.A.1.208.13	Cyclic nucleotide (cAMP and cGMP) efflux pump, MRP8 (ABCC11); also exports other nucleoside and nucleotide analogues, and confers resistance to fluoropyrimidines and the anti-AIDS drug, 2',3'-dideoxycytidine (Guo et al., 2003). Human earwax consists of wet and dry types. Dry earwax is frequent in East Asians, whereas wet earwax is common in other populations. A SNP, 538G --> A (rs17822931), in the ABCC11 gene is responsible for determination of earwax type. Cells with allele A show a lower excretory activity for cGMP than those with allele G. The 538G --> A SNP is the first example of DNA polymorphism determining a visible genetic trait (Yoshiura et al., 2006).	Animals	MRP8 (ABCC11) of Homo sapiens (Q9BX80)
3.A.1.208.14	The vacuole (tonoplast) ZmMrp3 anthocyanin pigment transporter (ABCF) (Goodman et al., 2004)	Plants	ZmMrp3 of Zea mays ZmMrp3 (MC-MC) (Q6J0P5)
3.A.1.208.15	The general organic anion exporter, MRP5 (MOATC). It exports cyclic AMP, cyclic GMP, 5'-FUMP, glutathione and glutathione conjugates and antimonial tartrate). Also transports reduced folates as well as mono-, di- and tri-glutamate derivatives of folic acid and methotrexate (Assaraf et al., 2006). When overexpressed, it can lower the intracellular concentration of nucleoside/nucleotide analogs, such as the antiviral compounds PMEA (9-(2-phosphonylmethoxyethyl)adenine) or ganciclovir, and of anticancer nucleobase analogs, such as 6-mercaptopurine, after their conversion into the respective nucleotides (Ritter et al., 2005).	Animals	MRP5 of Homo sapiens (O15440)
3.A.1.208.16	The vacuolar Abc2p (SPAC3F10.11c) transporter for xenobiotics, glutathione S-conjugates and monochlorobimane (Iwaki et al., 2006)	Yeast	Abc2p of Schizosaccharomyces pombe (MCMC; 1478 aas) (Q10185)
3.A.1.208.17	The vacuolar glutathione-conjugate and chlorophyll catabolite transporter, MRP3 (Tommasini et al., 1998)	Plants	MRP3 of Arabidopsis thaliana (Q9LK64)
3.A.1.208.18	Vacuolar glutathione conjugate, glutathione exporter; mediates cadmium detoxification and ade2 pigmentation in vivo (Sharma et al., 2002). (Most similar to Ycf1 of S. cerevisiae (TC# 3.A.1.208.11; 41% identity))	Plants	Bpt1 of Saccharomyces cerevisiae (P14772)
3.A.1.208.19	The possible HCO₃^- transporter, HLA3 (Duanmu et al., 2009).	Algae	HLA3 of Chlamydomonas reinhardtii (A8I268)
3.A.1.208.20	The vacuolar MRP1 (sequesters in the vacuole glutathione conjugates, folate mono-glutamates (pteroyl-1-glutamate) and antifolates (methotrexate); (Raichaudhuri et al. 2009) (86% identical to MRP2 (3.A.1.208.5))	Plants	MRP1 of Arabidopsis thaliana (Q9C8G9)
3.A.1.208.21	The thale cress protein ATMRP5 (ATABCC5), a high-affinity inositol hexakisphosphate transporter; involved in guard cell signaling and phytate storage (Nagy et al., 2009).	Plants	MRP5/ABCC5 of Arabidopsis thaliana (Q7GB25)
3.A.1.208.22	California mussel ABCC/MRP-type multixenobiotic resistance efflux pump (Luckenbach and Epel, 2008).	Animals	ABCC/MRP-type exporter of Mytilus californianus (B2WTI0)
3.A.1.208.23	The Sur2B (ABCC9) sulfonylurea receptor. The amino-terminal transmembrane domain of Sur2B binds Kir6.2 (Winkler et al., 2011). Dominant missense mutations in ABCC9, promoting open channel formation, cause Cantú syndrome (Harakalova et al., 2012; van Bon et al., 2012). This protein is part of an ATP-dependent potassium (K(ATP)) channel that couples the metabolic state of a cell with its electrical activity.	Animals	Sur2B of Homo sapiens (O60706)
3.A.1.208.24	Similar to MRP4 of man (TC#3.A.1.208.7).�A single amino acid mutation causes resistance to Bt toxin Cry1Ab in the silkworm, Bombyx mori (Atsumi et al., 2012). 83% identical to 3.A.1.208.6.	Insects	MRP4-like ABC transporter of Bombyx mori (G1UHW7)
3.A.1.208.25	The ABC-thiol (cysteine; glutathione) exporter, MrpA (Mukherjee et al., 2007). 83% identical to 3.A.1.208.6.	Kinetoplastid protozoans	MrpA of Leishmania donovani
3.A.1.209: The MHC Peptide Transporter (TAP) Family (ABCB)
3.A.1.209.1	MHC heterodimeric peptide exporter (TAP) (from cytoplasm to the endoplasmic reticulum) (TAP1=ABCB2; TAP2=ABCB3) (defects in TAP1 or TAP2 cause immunodeficiency) (TAP1/TAP2 is stabilized by tapasin isoforms 1, 2 and 3) (Raghuraman et al., 2002). TAP1 has 10 TMSs, 4 unique N-terminal TMSs and 6 TMSs that form the translocation pore with N- and C-termini in the cytosol (Schrodt et al., 2006). The TAP2 nucleotide binding site appears to be the main catalytic active site driving transport suggesting asymmetry in the transporter (Perria et al., 2006). The TAP complex shows strict coupling between peptide binding and ATP hydrolysis, revealing no basal ATPase activity in the absence of peptides (Herget et al., 2009). The transporter associated with antigen processing (TAP) plays a key role in the adaptive immune defense against infected or malignantly transformed cells by translocating proteasomal degradation products into the lumen of the endoplasmic reticulum for loading onto MHC class I molecules. TAP transports peptides from 8 to 40 residues, including even branched or modified molecules, suggestive of structural flexibility of the substrate-binding pocket. The bound peptides in side-chains' mobility was strongly restricted at the ends of the peptide, whereas the central region was flexible. Peptides bind to TAP in an extended kinked structure, analogous to those bound to MHC class I proteins (Herget et al., 2011).	Animals, yeast	TAP1/TAP2 of Homo sapiens
3.A.1.209.2	Homodimeric transporter ABCB9 or TAPL. Transports a broad spectrum of peptides (low affinity) from the cytosol to the lysosomal lumen. It exists in two forms (812 aas and 1257 aas). The latter full length protein confers resistance to taxanes and anthracyclines (Kawanobe et al., 2012). Resistance and transport were demonstrated for paclitaxel and docetaxel. Transports a broad range of peptides of 6-60aas (23aas optimal). Has also been detected in the ER. It is stabilized by interaction with LAMP-1 and LAMP-2 (see 9.A.16). (Demirel et al., 2012).	Animals	TAPL or ABCB9 of Homo sapiens (Q9NP78)
3.A.1.210: The Heavy Metal Transporter (HMT) Family (ABCB)
3.A.1.210.1	The putative mitochondrial iron transporter, ATM1 (possibly specific for iron-sulfur clusters)	Yeast; animals, protozoa bacteria	ATM1 of Saccharomyces cerevisiae
3.A.1.210.2	The vacuolar heavy metal tolerance protein precursor, HMT1 (transports phytochelins and Cd²⁺·phytochelin complexes) (Prévéral et al., 2009).	Yeast; animals, protozoa bacteria	HMT1 of Schizosaccharomyces pombe
3.A.1.210.3	The ABC transporter homologue	Yeast; animals, protozoa bacteria	ABC transporter homologue in Rickettsia prowazekii
3.A.1.210.4	ABC7 iron transporter (X-linked sideroblastis anemia protein) (also called ABCB7)	Yeast; animals, protozoa bacteria	ABC7 iron transporter of Homo sapiens
3.A.1.210.5	Multidrug resistance homologues, Pfmdr2, protein	Yeast; animals, protozoa bacteria	Pfmdr2 protein of Plasmodium falciparum
3.A.1.210.6	Mitochondrial outer membrane anionic porphyrin uptake half ABC transporter, ABCB6 (expressed in many mammalian tissues including fetal liver) in response to intracellular porphyrin; porphyrin uptake activates de novo porphyrin (haem) biosynthesis (Krishnamurthy et al., 2006).	Animals	ABCB6 of Homo sapiens (Q9NP58; 842 aas)
3.A.1.210.7	The homodimeric heavy metal tolerance protein 1, CeHMT-1 (exports phytochelatin ((γ-Glu-Cys)_n)-Cd² complexes) (Vatamaniuk et al., 2005).� The N-terminal hydrophobic extension domain is required (but not sufficient) for dimerization and therefore is essential for normal function (Kim et al. 2010).	Animals	CeHMT-1 of Caenorhabditis elegans (AAM33380)
3.A.1.210.8	Mitochondrial ABC transporter, ATM3 involved in iron homeostasis. There are three isoforms ATM1, ATM2 and ATM3 (Chen et al., 2007). ATM3 can replace the yeast iron/sulfur cluster exporter better than ATM1 or ATM2. It is most similar to the human and yeast homologues, TC# 3.A.1.210.4 and 3.A.1.210.1, 51% and 47% identical, respectively.	Plants	ATM3 of Arabidopsis thaliana (Q9LVM1)
3.A.1.210.9	The Ni²⁺/Co²⁺ exporter AtmA (Mikolay and Nies, 2009).	Bacteria	AmA of Cuperiavidus metallidurans (Q1LRE9).
3.A.1.211: The Cholesterol/Phospholipid/Retinal (CPR) Flippase Family (ABCA)
3.A.1.211.1	The cholesterol/phospholipid flippase, ABC1 (called ABCA1 in humans; Tangier disease proteins; 2261 aas; sp: O95477). An amphipathic helical region of the N-terminal barrel of the phospholipid transfer protein (PLTP) is critical for ABCA1-dependent cholesterol efflux (Oram et al., 2008). PLTP helix 144-163 removes lipid domains formed by ABCA1, stabilizing ABCA1, interacting with phospholipids, and promoting phospholipid transfer by direct interactions with ABCA1. May transport sphingosine-1-phosphate (Kobayashi et al., 2009). May protect from cardiovascular disease and diabetes (Tang and Oram, 2009). Mediates efflux of cellular cholesterol and phospholipids to apoA-I (Voloshyna and Reiss, 2011). Hyperglycemia accelerates ABCA1 degradation (Chang et al. 2013).	Animals and plants	ABC1 of Mus musculus
3.A.1.211.2	The retinal-specific ABC transporter (RIM protein, ABCR or ABCA4) (Stargardt's disease protein, involved in retinal/macular degeneration) in the rod outer segment. ABCA4 is an unusual uptake porter that flips N-retinylidene-phosphatidylethanolamine, a product generated from the photobleaching of rhodopsin, from the lumen to the cytoplasmic side of disc membranes following the photobleaching of rhodopsin, insuring that retinoids do not accumulate in disc membranes Molday, 2007; Molday et al. 2009; Tsybovsky et al. 2013). Also transports several vitamin A derivatives (Sun, 2011). ABCA4 also actively transports phosphatidylethanolamine in the same direction. Mutations known to cause Stargardt disease decrease N-retinylidene-phosphatidylethanolamine and phosphatidylethanolamine transport activity of ABCA4 (Quazi et al. 2012).	Animals	RIM protein (ABCR) of Homo sapiens
3.A.1.211.3	Multidrug resistance pump, ABCA2 (ABC2). Mediates trafficking of LDL-derived free cholesterol (Voloshyna and Reiss, 2011).	Animals	ABCA2 of Homo sapiens
3.A.1.211.4	The aced cell death 7 (ced-7) protein (translocates molecules that mediate adhesion between dying and engulfing embryonic cells during programmed death).	Animals	Ced-7 of Caenorhabditis elegans (P34358)
3.A.1.211.5	The surfactant-secreting porter, ABCA3 (exports lipids and proteins into lamellar bodies). Fatal surfactant deficiency (FSD) can result from mutations in ABCA3, causing abnormal intracellular localization (type I) or decreased ATP hydrolysis (type II). ABCA3 is found in lamellar bodies of lung alveolar type II cells where it probably secretes surfactants (mixture of lipids; e.g., PC) and proteins (e.g., surfactant proteins A, B, C and D) stored in lamellar bodies and exocytosed (Matsumura et al., 2006). ABCA3 plays an essential role in pulmonary surfactant lipid metabolism and lamellar body biogenesis, probably by transporting these lipids as substrates (Ban et al., 2007). Cheong et al., 2007 have shown that ABCA3 is critical for lamellar body biogenesis in mice. They suggest it functions in surfactant-protein B processing and lung development late in gestation. Lymphoma exosomes shield target cells from antibody attack, and exosome biogenesis is modulated by lysosome-associated ABCA3 which mediates resistance to chemotherapy. Silencing ABCA3 enhances susceptability of target cells to antibody-mediated lysis. Mechanisms of cancer cell resistance to drugs and antibodies are linked in an ABCA3-dependent pathway of exosome secretion (Aung et al., 2011).	Animals	ABCA3 of Homo sapiens (Q99758)
3.A.1.211.6	Xenobiotic transporter, ABCA8 (transports estradiol-β-glucuronide, taurocholate, LTC4, para-amino-hippurate and ochratoxin-A (Tsuruoka et al., 2002)	Animals	ABCA8 of Homo sapiens (O94911)
3.A.1.211.7	Half sized ABCA exporter, AbcA	Amoeba	AbcA of Dictyostelium discoideum M-C 655 aas; (Q94479)
3.A.1.211.8	AbcA12 Keratinocyte lipid transporter. Transports lipids in lamellar granules to the apical surface of granular layer keratinocytes. Extracellular lipids, including ceramide, are thought to be essential for skin barrier function. ABCA12 mutations underlie the three main types of autosomal recessive congenital ichthyoses: harlequin ichthyosis, lamellar ichthyosis and congenital ichthyosiform erythroderma. ABCA12 mutations lead to defective lipid transport via lamellar granules in the keratinocytes, resulting in malformation of the epidermal lipid barrier and ichthyosis phenotypes. Lipid transport by ABCA12 is indispensable for intact differentiation of keratinocytes (Akiyama, 2011).	Animals	AbcA12 of Mus musculus (B9EKF0)
3.A.1.211.9	ABCA5. Mediates cholesterol efflux to HDL3 (Voloshyna and Reiss, 2011).	Animals	ABCA5 of Homo sapiens (Q8WWZ7)
3.A.1.211.10	ABCA7. Regulates cellular efflux of phospholipids but not cholesterol, to apo A-1 (Voloshyna and Reiss, 2011).	Animals	ABCA7 of Homo sapiens (Q8IZY2)
3.A.1.211.11	AOH1; ABCA1 transporter. Substrates unknown.	Plants	ABCA1 of Arabidopsis thaliana
3.A.1.212: The Mitochondrial Peptide Exporter (MPE) Family (ABCB)
3.A.1.212.1	The mitochondrial peptide exporter, Mdl1p (exports peptides of 6-21 amino acyl residues from the mitochondrial matrix as well as degradation products of misassembled respiratory chain complexes) (Janas et al., 2003; van der Does et al., 2006; Gompf et al., 2007). A leaderless Mdl1p targets to the ER membrane instead of to the mitochondria (Gompf et al., 2007).	Yeast	Mdl1p of Saccharomyces cerevisiae (P33310)
3.A.1.212.2	ABC mitochondrial peptide/MDR half transporter, MdlB. High copy number suppressor of ATM1 [iron-sulfur cluster transporter (3.A.1.210.1)]	Bacteria	Md1B of Saccharomyces cerevisiae (M-C) (P33311)