2fed
From Proteopedia
| Line 7: | Line 7: | ||
|ACTIVITY= | |ACTIVITY= | ||
|GENE= clcA, eriC ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 Escherichia coli]) | |GENE= clcA, eriC ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 Escherichia coli]) | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY=[[1ots|1OTS]], [[2fec|2FEC]], [[2fee|2FEE]] | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2fed FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2fed OCA], [http://www.ebi.ac.uk/pdbsum/2fed PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=2fed RCSB]</span> | ||
}} | }} | ||
| Line 29: | Line 32: | ||
[[Category: Walden, M P.]] | [[Category: Walden, M P.]] | ||
[[Category: Williams, C.]] | [[Category: Williams, C.]] | ||
| - | [[Category: | + | [[Category: chloride/proton exchange transporter]] |
| + | [[Category: clc-ec1]] | ||
| + | [[Category: clca_ecoli]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 03:01:41 2008'' |
Revision as of 00:01, 31 March 2008
| |||||||
| , resolution 3.317Å | |||||||
|---|---|---|---|---|---|---|---|
| Gene: | clcA, eriC (Escherichia coli) | ||||||
| Related: | 1OTS, 2FEC, 2FEE
| ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Structure of the E203Q mutant of the Cl-/H+ exchanger CLC-ec1 from E.Coli
Overview
CLC-ec1 is a prokaryotic CLC-type Cl(-)/H+ exchange transporter. Little is known about the mechanism of H+ coupling to Cl-. A critical glutamate residue, E148, was previously shown to be required for Cl(-)/H+ exchange by mediating proton transfer between the protein and the extracellular solution. To test whether an analogous H+ acceptor exists near the intracellular side of the protein, we performed a mutagenesis scan of inward-facing carboxyl-bearing residues and identified E203 as the unique residue whose neutralization abolishes H+ coupling to Cl- transport. Glutamate at this position is strictly conserved in all known CLCs of the transporter subclass, while valine is always found here in CLC channels. The x-ray crystal structure of the E203Q mutant is similar to that of the wild-type protein. Cl- transport rate in E203Q is inhibited at neutral pH, and the double mutant, E148A/E203Q, shows maximal Cl- transport, independent of pH, as does the single mutant E148A. The results argue that substrate exchange by CLC-ec1 involves two separate but partially overlapping permeation pathways, one for Cl- and one for H+. These pathways are congruent from the protein's extracellular surface to E148, and they diverge beyond this point toward the intracellular side. This picture demands a transport mechanism fundamentally different from familiar alternating-access schemes.
About this Structure
2FED is a Single protein structure of sequence from Escherichia coli and Homo sapiens. Full crystallographic information is available from OCA.
Reference
Separate ion pathways in a Cl-/H+ exchanger., Accardi A, Walden M, Nguitragool W, Jayaram H, Williams C, Miller C, J Gen Physiol. 2005 Dec;126(6):563-70. PMID:16316975
Page seeded by OCA on Mon Mar 31 03:01:41 2008
