2fed
From Proteopedia
| Line 1: | Line 1: | ||
| - | [[Image:2fed.gif|left|200px]] | + | [[Image:2fed.gif|left|200px]] |
| - | + | ||
| - | '''Structure of the E203Q mutant of the Cl-/H+ exchanger CLC-ec1 from E.Coli''' | + | {{Structure |
| + | |PDB= 2fed |SIZE=350|CAPTION= <scene name='initialview01'>2fed</scene>, resolution 3.317Å | ||
| + | |SITE= | ||
| + | |LIGAND= | ||
| + | |ACTIVITY= | ||
| + | |GENE= clcA, eriC ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 Escherichia coli]) | ||
| + | }} | ||
| + | |||
| + | '''Structure of the E203Q mutant of the Cl-/H+ exchanger CLC-ec1 from E.Coli''' | ||
| + | |||
==Overview== | ==Overview== | ||
| Line 7: | Line 16: | ||
==About this Structure== | ==About this Structure== | ||
| - | 2FED is a [ | + | 2FED is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] and [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2FED OCA]. |
==Reference== | ==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:[http:// | + | 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:[http://www.ncbi.nlm.nih.gov/pubmed/16316975 16316975] |
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
| Line 22: | Line 31: | ||
[[Category: clc-ec1; clca_ecoli; chloride/proton exchange transporter]] | [[Category: clc-ec1; clca_ecoli; chloride/proton exchange transporter]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 16:51:30 2008'' |
Revision as of 14:51, 20 March 2008
| |||||||
| , resolution 3.317Å | |||||||
|---|---|---|---|---|---|---|---|
| Gene: | clcA, eriC (Escherichia coli) | ||||||
| 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 Thu Mar 20 16:51:30 2008
