TCDB is operated by the Saier Lab Bioinformatics Group
« See all members of the family


2.A.24.1.1
Citrate:Na+ symporter, CitS.  Kebbel et al. 2013 presented the three-dimensional map of dimeric CitS obtained with electron crystallography. Each monomer has 13 alpha-helical transmembrane segments; six are organized in a distal helix cluster and seven in the central dimer interface domain. Based on structural analyses and comparison to VcINDY, a molecular model with assigned helices, a model with internal structural symmetry was proposed. Projections of CitS in several conformational states induced by the presence and absence of sodium and citrate as substrates were also proposed. Citrate binding induces a defined movement of alpha helices within the distal helical cluster.  Kebbel et al. 2013 proposed a substrate translocation site and conformational changes that are in agreement with the "alternating access" model.

Accession Number:P31602
Protein Name:CITN aka CitS
Length:446
Molecular Weight:47558.00
Species:Klebsiella pneumoniae [573]
Number of TMSs:11
Location1 / Topology2 / Orientation3: Cell membrane1 / Multi-pass membrane protein2
Substrate Citrate

Cross database links:

Pfam: PF03390   

Gene Ontology

GO:0016021 C:integral to membrane
GO:0005886 C:plasma membrane
GO:0008514 F:organic anion transmembrane transporter act...
GO:0015293 F:symporter activity
GO:0006101 P:citrate metabolic process
GO:0015711 P:organic anion transport

References (2)

[1] “Nucleotide sequence and functional properties of a sodium-dependent citrate transport system from Klebsiella pneumoniae.”  van der Rest M.E.et.al.   1577734
[2] “Membrane topology of the sodium ion-dependent citrate carrier of Klebsiella pneumoniae. Evidence for a new structural class of secondary transporters.”  van Geest M.et.al.   8810332

External Searches:

  • Search: DB with
  • BLAST ExPASy (Swiss Institute of Bioinformatics (SIB) BLAST)
  • CDD Search (Conserved Domain Database)
  • Search COGs (Clusters of Orthologous Groups of proteins)
  • 2° Structure (Network Protein Sequence Analysis)

Analyze:

Predict TMSs (Predict number of transmembrane segments)
Window Size: Angle:  
Window Size: Angle:  
FASTA formatted sequence
1:	MTNMSQPPAT EKKGVSDLLG FKIFGMPLPL YAFALITLLL SHFYNALPTD IVGGFAIMFI 
61:	IGAIFGEIGK RLPIFNKYIG GAPVMIFLVA AYFVYAGIFT QKEIDAISNV MDKSNFLNLF 
121:	IAVLITGAIL SVNRRLLLKS LLGYIPTILM GIVGASIFGI AIGLVFGIPV DRIMMLYVLP 
181:	IMGGGNGAGA VPLSEIYHSV TGRSREEYYS TAIAILTIAN IFAIVFAAVL DIIGKKHTWL 
241:	SGEGELVRKA SFKVEEDEKT GQITHRETAV GLVLSTTCFL LAYVVAKKIL PSIGGVAIHY 
301:	FAWMVLIVAA LNASGLCSPE IKAGAKRLSD FFSKQLLWVL MVGVGVCYTD LQEIINAITF 
361:	ANVVIAAIIV IGAVLGAAIG GWLMGFFPIE SAITAGLCMA NRGGSGDLEV LSACNRMNLI 
421:	SYAQISSRLG GGIVLVIASI VFGMMI