3KCV: Structure of formate channel

FocA is a representative member of the formate-nitrite transporter family, which transports short-chain acids in bacteria, archaea, fungi, algae and parasites. The structure and transport mechanism of the formate-nitrite transporter family remain unknown. Here we report the crystal structure of Escherichia coli FocA at 2.25 A resolution. FocA forms a symmetric pentamer, with each protomer consisting of six transmembrane segments. Despite a lack of sequence homology, the overall structure of the FocA protomer closely resembles that of aquaporin and strongly argues that FocA is a channel, rather than a transporter. Structural analysis identifies potentially important channel residues, defines the channel path and reveals two constriction sites. Unlike aquaporin, FocA is impermeable to water but allows the passage of formate. A structural and biochemical investigation provides mechanistic insights into the channel activity of FocA.
PDB ID: 3KCVDownload
MMDB ID: 78459
PDB Deposition Date: 2009/10/22
Updated in MMDB: 2009/12
Experimental Method:
x-ray diffraction
Resolution: 3.198  Å
Source Organism:
Similar Structures:
Biological Unit for 3KCV: pentameric; determined by author and by software (PISA)
Molecular Components in 3KCV
Label Count Molecule
Proteins (5 molecules)
Probable Formate Transporter 1(Gene symbol: ECs0987)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB