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| | ==Structure of the E203Q mutant of the Cl-/H+ exchanger CLC-ec1 from E.Coli== | | ==Structure of the E203Q mutant of the Cl-/H+ exchanger CLC-ec1 from E.Coli== |
| - | <StructureSection load='2fec' size='340' side='right' caption='[[2fec]], [[Resolution|resolution]] 3.97Å' scene=''> | + | <StructureSection load='2fec' size='340' side='right'caption='[[2fec]], [[Resolution|resolution]] 3.97Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[2fec]] is a 6 chain structure with sequence from [http://en.wikipedia.org/wiki/"bacillus_coli"_migula_1895 "bacillus coli" migula 1895] and [http://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2FEC OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2FEC FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[2fec]] is a 6 chain structure with sequence from [https://en.wikipedia.org/wiki/"bacillus_coli"_migula_1895 "bacillus coli" migula 1895] and [https://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2FEC OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2FEC FirstGlance]. <br> |
| - | </td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1ots|1ots]], [[2fed|2fed]], [[2fee|2fee]]</td></tr> | + | </td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[1ots|1ots]], [[2fed|2fed]], [[2fee|2fee]]</div></td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">clcA, eriC ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 "Bacillus coli" Migula 1895])</td></tr> | + | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">clcA, eriC ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 "Bacillus coli" Migula 1895])</td></tr> |
| - | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2fec FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2fec OCA], [http://pdbe.org/2fec PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=2fec RCSB], [http://www.ebi.ac.uk/pdbsum/2fec PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=2fec ProSAT]</span></td></tr> | + | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2fec FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2fec OCA], [https://pdbe.org/2fec PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2fec RCSB], [https://www.ebi.ac.uk/pdbsum/2fec PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2fec ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/CLCA_ECOLI CLCA_ECOLI]] Proton-coupled chloride transporter. Functions as antiport system and exchanges two chloride ions for 1 proton. Probably acts as an electrical shunt for an outwardly-directed proton pump that is linked to amino acid decarboxylation, as part of the extreme acid resistance (XAR) response.<ref>PMID:12384697</ref> <ref>PMID:14985752</ref> <ref>PMID:16341087</ref> <ref>PMID:16905147</ref> <ref>PMID:18678918</ref> | + | [[https://www.uniprot.org/uniprot/CLCA_ECOLI CLCA_ECOLI]] Proton-coupled chloride transporter. Functions as antiport system and exchanges two chloride ions for 1 proton. Probably acts as an electrical shunt for an outwardly-directed proton pump that is linked to amino acid decarboxylation, as part of the extreme acid resistance (XAR) response.<ref>PMID:12384697</ref> <ref>PMID:14985752</ref> <ref>PMID:16341087</ref> <ref>PMID:16905147</ref> <ref>PMID:18678918</ref> |
| | == Evolutionary Conservation == | | == Evolutionary Conservation == |
| | [[Image:Consurf_key_small.gif|200px|right]] | | [[Image:Consurf_key_small.gif|200px|right]] |
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| | [[Category: Bacillus coli migula 1895]] | | [[Category: Bacillus coli migula 1895]] |
| | [[Category: Human]] | | [[Category: Human]] |
| | + | [[Category: Large Structures]] |
| | [[Category: Accardi, A]] | | [[Category: Accardi, A]] |
| | [[Category: Jayaram, H]] | | [[Category: Jayaram, H]] |
| Structural highlights
Function
[CLCA_ECOLI] Proton-coupled chloride transporter. Functions as antiport system and exchanges two chloride ions for 1 proton. Probably acts as an electrical shunt for an outwardly-directed proton pump that is linked to amino acid decarboxylation, as part of the extreme acid resistance (XAR) response.[1] [2] [3] [4] [5]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
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.
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[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Iyer R, Iverson TM, Accardi A, Miller C. A biological role for prokaryotic ClC chloride channels. Nature. 2002 Oct 17;419(6908):715-8. PMID:12384697 doi:10.1038/nature01000
- ↑ Accardi A, Miller C. Secondary active transport mediated by a prokaryotic homologue of ClC Cl- channels. Nature. 2004 Feb 26;427(6977):803-7. PMID:14985752 doi:10.1038/nature02314
- ↑ Lobet S, Dutzler R. Ion-binding properties of the ClC chloride selectivity filter. EMBO J. 2006 Jan 11;25(1):24-33. Epub 2005 Dec 8. PMID:16341087
- ↑ Nguitragool W, Miller C. Uncoupling of a CLC Cl-/H+ exchange transporter by polyatomic anions. J Mol Biol. 2006 Sep 29;362(4):682-90. Epub 2006 Aug 14. PMID:16905147 doi:10.1016/j.jmb.2006.07.006
- ↑ Jayaram H, Accardi A, Wu F, Williams C, Miller C. Ion permeation through a Cl--selective channel designed from a CLC Cl-/H+ exchanger. Proc Natl Acad Sci U S A. 2008 Aug 12;105(32):11194-9. Epub 2008 Aug 4. PMID:18678918
- ↑ Accardi A, Walden M, Nguitragool W, Jayaram H, Williams C, Miller C. Separate ion pathways in a Cl-/H+ exchanger. J Gen Physiol. 2005 Dec;126(6):563-70. PMID:16316975 doi:10.1085/jgp.200509417
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