3Q7K

Formate Channel FocA from Salmonella typhimurium

• PDB DOI: https://doi.org/10.2210/pdb3Q7K/pdb

• Classification: TRANSPORT PROTEIN
• Organism(s): Salmonella enterica subsp. enterica serovar Typhi str. CT18
• Expression System: Escherichia coli
• Mutation(s): No 
• Membrane Protein: Yes  OPMPDBTMMemProtMDmpstruc


• Deposited: 2011-01-05 Released: 2011-04-27 
• Deposition Author(s): Lue, W., Du, J., Wacker, T., Gerbig-Smentek, E., Andrade, S.L.A., Einsle, O.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.80 Å
• R-Value Free: 0.254 
• R-Value Work: 0.219 
• R-Value Observed: 0.220 

Literature

pH-dependent gating in a FocA formate channel

Lu, W., Du, J., Wacker, T., Gerbig-Smentek, E., Andrade, S.L., Einsle, O.

(2011) Science 332: 352-354

• PubMed: 21493860 
• DOI: https://doi.org/10.1126/science.1199098
• Primary Citation of Related Structures:  
  3Q7K


• PubMed Abstract: 
  

  The formate transporter FocA was described to switch its mode of operation from a passive export channel at high external pH to a secondary active formate/H(+) importer at low pH. The crystal structure of Salmonella typhimurium FocA at pH 4.0 shows that this switch involves a major rearrangement of the amino termini of individual protomers in the pentameric channel. The amino-terminal helices open or block transport in a concerted, cooperative action that indicates how FocA is gated in a pH-dependent way. Electrophysiological studies show that the protein acts as a specific formate channel at pH 7.0 and that it closes upon a shift of pH to 5.1.

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Organizational Affiliation: 

Lehrstuhl für Biochemie, Institut für organische Chemie und Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg, Germany.

Biological Assembly 1  

Global Symmetry: Cyclic - C5  (Explore in 3D)
Global Stoichiometry: Homo 5-mer - A5 

Biological assembly 1 assigned by authors and generated by PISA (software)

Biological Assembly 2  

Global Symmetry: Cyclic - C5  (Explore in 3D)
Global Stoichiometry: Homo 5-mer - A5 

Biological assembly 2 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 321.22 kDa 
• Atom Count: 19,151 
• Modelled Residue Count: 2,523 
• Deposited Residue Count: 2,930 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Probable formate transporter	A, B, C, D, E, F [auth G], G [auth H], H [auth I], I [auth J], J [auth K]	293	Salmonella enterica subsp. enterica serovar Typhi str. CT18	Mutation(s): 0  Gene Names: focA, STY0974, t1960 Membrane Entity: Yes
UniProt
Find proteins for Q7CQU0 (Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720)) Explore Q7CQU0  Go to UniProtKB:  Q7CQU0

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
FMT	K [auth A], L [auth B], M [auth B], N [auth C], O [auth C], P [auth D], Q [auth H], R [auth H], S [auth H], T [auth I], U [auth J], V [auth K], W [auth K]	FORMIC ACID C H2 O2 BDAGIHXWWSANSR-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.80 Å
• R-Value Free: 0.254 
• R-Value Work: 0.219 
• R-Value Observed: 0.220 
• Space Group: P 1 2₁ 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 105.951	α = 90
b = 205.723	β = 115.49
c = 106.046	γ = 90

Software Package:

Software Name	Purpose
MOLREP	phasing
REFMAC	refinement
MOSFLM	data reduction
SCALA	data scaling

Structure Validation

Entry History 

Deposition Data

• Released Date: 2011-04-27 
Deposition Author(s): Lue, W., Du, J., Wacker, T., Gerbig-Smentek, E., Andrade, S.L.A., Einsle, O.

Revision History  

• Version 1.0: 2011-04-27
  Type: Initial release
  
• Version 1.1: 2011-07-13
  Changes: Version format compliance
• Version 1.2: 2017-11-08
  Changes: Refinement description
• Version 1.3: 2023-11-01
  Changes: Data collection, Database references, Derived calculations, Refinement description