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| | ==An open-pore structure of a bacterial pentameric ligand-gated ion channel== | | ==An open-pore structure of a bacterial pentameric ligand-gated ion channel== |
| - | <StructureSection load='3eam' size='340' side='right' caption='[[3eam]], [[Resolution|resolution]] 2.90Å' scene=''> | + | <StructureSection load='3eam' size='340' side='right'caption='[[3eam]], [[Resolution|resolution]] 2.90Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[3eam]] is a 5 chain structure with sequence from [http://en.wikipedia.org/wiki/Glovo Glovo]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3EAM OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3EAM FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[3eam]] is a 5 chain structure with sequence from [https://en.wikipedia.org/wiki/Glovo Glovo]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3EAM OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3EAM FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=LMT:DODECYL-BETA-D-MALTOSIDE'>LMT</scene>, <scene name='pdbligand=PC1:1,2-DIACYL-SN-GLYCERO-3-PHOSPHOCHOLINE'>PC1</scene></td></tr> | + | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=LMT:DODECYL-BETA-D-MALTOSIDE'>LMT</scene>, <scene name='pdbligand=PC1:1,2-DIACYL-SN-GLYCERO-3-PHOSPHOCHOLINE'>PC1</scene></td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">glr4197 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=33072 GLOVO])</td></tr> | + | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">glr4197 ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=33072 GLOVO])</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=3eam FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3eam OCA], [http://pdbe.org/3eam PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3eam RCSB], [http://www.ebi.ac.uk/pdbsum/3eam PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=3eam 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=3eam FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3eam OCA], [https://pdbe.org/3eam PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3eam RCSB], [https://www.ebi.ac.uk/pdbsum/3eam PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3eam ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/GLIC_GLOVI GLIC_GLOVI]] Cationic channel with similar permeabilities for Na(+) and K(+), that is activated by an increase of the proton concentration on the extracellular side. Displays no permeability for chloride ions. Shows slow kinetics of activation, no desensitization and a single channel conductance of 8 pS. Might contribute to adaptation to external pH change.<ref>PMID:17167423</ref> | + | [[https://www.uniprot.org/uniprot/GLIC_GLOVI GLIC_GLOVI]] Cationic channel with similar permeabilities for Na(+) and K(+), that is activated by an increase of the proton concentration on the extracellular side. Displays no permeability for chloride ions. Shows slow kinetics of activation, no desensitization and a single channel conductance of 8 pS. Might contribute to adaptation to external pH change.<ref>PMID:17167423</ref> |
| | == Evolutionary Conservation == | | == Evolutionary Conservation == |
| | [[Image:Consurf_key_small.gif|200px|right]] | | [[Image:Consurf_key_small.gif|200px|right]] |
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| | ==See Also== | | ==See Also== |
| - | *[[Ion channels|Ion channels]] | + | *[[Ion channels 3D structures|Ion channels 3D structures]] |
| | == References == | | == References == |
| | <references/> | | <references/> |
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| | </StructureSection> | | </StructureSection> |
| | [[Category: Glovo]] | | [[Category: Glovo]] |
| | + | [[Category: Large Structures]] |
| | [[Category: Baaden, M]] | | [[Category: Baaden, M]] |
| | [[Category: Bocquet, N]] | | [[Category: Bocquet, N]] |
| Structural highlights
Function
[GLIC_GLOVI] Cationic channel with similar permeabilities for Na(+) and K(+), that is activated by an increase of the proton concentration on the extracellular side. Displays no permeability for chloride ions. Shows slow kinetics of activation, no desensitization and a single channel conductance of 8 pS. Might contribute to adaptation to external pH change.[1]
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
Pentameric ligand-gated ion channels from the Cys-loop family mediate fast chemo-electrical transduction, but the mechanisms of ion permeation and gating of these membrane proteins remain elusive. Here we present the X-ray structure at 2.9 A resolution of the bacterial Gloeobacter violaceus pentameric ligand-gated ion channel homologue (GLIC) at pH 4.6 in an apparently open conformation. This cationic channel is known to be permanently activated by protons. The structure is arranged as a funnel-shaped transmembrane pore widely open on the outer side and lined by hydrophobic residues. On the inner side, a 5 A constriction matches with rings of hydrophilic residues that are likely to contribute to the ionic selectivity. Structural comparison with ELIC, a bacterial homologue from Erwinia chrysanthemi solved in a presumed closed conformation, shows a wider pore where the narrow hydrophobic constriction found in ELIC is removed. Comparative analysis of GLIC and ELIC reveals, in concert, a rotation of each extracellular beta-sandwich domain as a rigid body, interface rearrangements, and a reorganization of the transmembrane domain, involving a tilt of the M2 and M3 alpha-helices away from the pore axis. These data are consistent with a model of pore opening based on both quaternary twist and tertiary deformation.
X-ray structure of a pentameric ligand-gated ion channel in an apparently open conformation.,Bocquet N, Nury H, Baaden M, Le Poupon C, Changeux JP, Delarue M, Corringer PJ Nature. 2009 Jan 1;457(7225):111-4. Epub 2008 Nov 5. PMID:18987633[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Bocquet N, Prado de Carvalho L, Cartaud J, Neyton J, Le Poupon C, Taly A, Grutter T, Changeux JP, Corringer PJ. A prokaryotic proton-gated ion channel from the nicotinic acetylcholine receptor family. Nature. 2007 Jan 4;445(7123):116-9. Epub 2006 Dec 10. PMID:17167423 doi:10.1038/nature05371
- ↑ Bocquet N, Nury H, Baaden M, Le Poupon C, Changeux JP, Delarue M, Corringer PJ. X-ray structure of a pentameric ligand-gated ion channel in an apparently open conformation. Nature. 2009 Jan 1;457(7225):111-4. Epub 2008 Nov 5. PMID:18987633 doi:10.1038/nature07462
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