TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
*1.A.16.1.1









Formate uptake/efflux permease, FocA.  It catalyzes bidirectional transport, has a pentameric aquaporin-like (TC# 1.A.8) structure, and may function by a channel-type mechanism (Falke et al., 2009; Wang et al. 2009). The structure at 2.25 Å resolution has been determined (Wang et al., 2009).  The protein is encoded in an operon with pyruvate-formate lyase, PflB.  A pyruvate:formate antiport mechanism has been suggested (Moraes and Reithmeier 2012). The C-terminal 6 aas are required for formate transport, but not for homopentamer formation (Hunger et al. 2017).  The N-terminus of FocA interacts with PflB, and this interaction is essential for optimal formate translocation (Doberenz et al. 2014). In fact, the GREs, TdcE and PflB, interact with the FNT channel protein, probably to control formate translocation by FocA (Falke et al. 2016).

Bacteria
Proteobacteria
FocA of E. coli (P0AC23)
*1.A.16.1.2









Probable formate transporter 2 (Formate channel 2), FocB (Andrews et al. 1997).

Bacteria
Proteobacteria
FocB of Escherichia coli
*1.A.16.1.3









Formate channel, FocA. Competition of formate by Thr90 from the Ω loop may open the channel (Waight et al., 2010).

Bacteria
Proteobacteria
FocA of Vibrio cholerae (F9A868)
*1.A.16.2.1









Formate-specific channel protein, FdhC of 280 aas (Nölling and Reeve 1997).

Archaea
Euryarchaeota
FdhC of Methanobacterium thermoformicium
*1.A.16.2.2









Nitrate uptake porter, NitA (Unkles et al., 1991; 2011)

Eukaryota
Fungi
NitA of Aspergillus (Emericella) nidulans
*1.A.16.2.3









Probable formate uptake permease (Wood et al., 2003).

Archaea
Euryarchaeota
FdhC of Methanococcus maripaludis
*1.A.16.2.4









Nitrite uptake porter of 355 aas, Nar1.

Eukaryota
Viridiplantae
Nar1 of Chlamydomonas reinhardtii (Chlamydomonas smithii)
*1.A.16.2.5









Nitrite channel transporter, NirC, of 382 aas. Structure/function studies including the x-ray structure of the Salmonella orthologue have been reported (Rycovska-Blume et al. 2015).

Archaea
Crenarchaeota
NirC of Thermofilum pendens
*1.A.16.2.6









Nitrite/Nitrate exporter of 476 aas, Nar1 (Cabrera et al. 2014).

Eukaryota
Fungi
Nar1 of Pichia angusta (Yeast) (Hansenula polymorpha)
*1.A.16.2.7









FNT homologue of 313 aas and 6 TMSs that transports lactacte.  Trophozoites are inhibited by drugs such as MMVOO7839 (Golldack et al. 2017, Hapuarachchi et al. 2017).

Eukaryota
Apicomplexa
PfFNT of Plasmodium falciparum
*1.A.16.2.8









Formate/nitrite (FNT) transporter of 356 aas and 6 TMSs.

Eukaryota
Entamoebidae
FNT of Entamoeba histolytica
*1.A.16.3.1









Nitrite uptake/efflux channel (Jia et al. 2009).

Bacteria
Proteobacteria
NirC of E. coli (P0AC26)
*1.A.16.3.2









Uncharacterized transporter YwcJ

Bacteria
Firmicutes
YwcJ of Bacillus subtilis
*1.A.16.3.3









Hydrosulfide (hydrogen sulfide; HS-), Fnt3 (Hsc) channel.  Also probably transports chloride, formate and nitrite. The 3-d crystal structure (2.2Å resolution in the closed state) is known (PDB# 3TE2) (Czyzewski and Wang, 2012). The Fnt3 gene is linked to the asrABC operon encoding the sulfite (SO32-) reductase that gives HS- as the product (Czyzewski and Wang 2012).

Bacteria
Firmicutes
Hsc or Fnt3 HS- channel of Clostridium difficile (Q186B7)
*1.A.16.3.4









Nitrate transporter, NirC, of 268 aas and 6 TMSs.

Bacteria
Proteobacteria
NirC of Klebsiella oxytoca
*1.A.16.4.1









Inner membrane protein, YfdC (310aas; 6 TMSs).  May be involved in surfactant resistance (Nakata et al. 2010).

Bacteria
Proteobacteria
YfdC of E. coli (P37327)
*1.A.16.4.2









Putative FNT transporter of 346 aas

Bacteria
Proteobacteria
FNT transporter of Psychrobacter arcticus
*1.A.16.4.3









FNT homologue  of 313 aas

Archaea
Euryarchaeota
FNT homologue of Salinarchaeum sp. Harcht-Bsk1
*1.A.16.5.1









FNT homologue of 230 aas

Bacteria
Tenericutes
FNT homologue of Acholeplasma palmae
*1.A.16.5.2









FNT homologue of 213 aas

Bacteria
Tenericutes
FNT homologue of Acholeplasma laidlawii