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| | ==X-ray structure of the pentameric ligand gated ion channel of Gloebacter violaceus (GLIC) in a presumptive open conformation== | | ==X-ray structure of the pentameric ligand gated ion channel of Gloebacter violaceus (GLIC) in a presumptive open conformation== |
| - | <StructureSection load='3ehz' size='340' side='right' caption='[[3ehz]], [[Resolution|resolution]] 3.10Å' scene=''> | + | <StructureSection load='3ehz' size='340' side='right'caption='[[3ehz]], [[Resolution|resolution]] 3.10Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[3ehz]] 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=3EHZ OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3EHZ FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[3ehz]] is a 5 chain structure with sequence from [https://en.wikipedia.org/wiki/Gloeobacter_violaceus Gloeobacter violaceus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3EHZ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3EHZ FirstGlance]. <br> |
| - | </td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[3ei0|3ei0]]</td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 3.1Å</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=3ehz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ehz OCA], [http://pdbe.org/3ehz PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3ehz RCSB], [http://www.ebi.ac.uk/pdbsum/3ehz PDBsum]</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=3ehz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ehz OCA], [https://pdbe.org/3ehz PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3ehz RCSB], [https://www.ebi.ac.uk/pdbsum/3ehz PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3ehz 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]] |
| | Check<jmol> | | Check<jmol> |
| | <jmolCheckbox> | | <jmolCheckbox> |
| - | <scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/eh/3ehz_consurf.spt"</scriptWhenChecked> | + | <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/eh/3ehz_consurf.spt"</scriptWhenChecked> |
| | <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | | <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> |
| | <text>to colour the structure by Evolutionary Conservation</text> | | <text>to colour the structure by Evolutionary Conservation</text> |
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| | ==See Also== | | ==See Also== |
| - | *[[Ion channels|Ion channels]] | + | *[[Ion channels 3D structures|Ion channels 3D structures]] |
| | == References == | | == References == |
| | <references/> | | <references/> |
| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Glovo]] | + | [[Category: Gloeobacter violaceus]] |
| - | [[Category: Dutzler, R]] | + | [[Category: Large Structures]] |
| - | [[Category: Hilf, R J.C]] | + | [[Category: Dutzler R]] |
| - | [[Category: Cation selective channel]] | + | [[Category: Hilf RJC]] |
| - | [[Category: Membrane protein]]
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| - | [[Category: Pentameric ligand gated ion channel]]
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| - | [[Category: Prokaryotic cys-loop receptor]]
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| 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
The X-ray structure of a pentameric ligand-gated ion channel from Erwinia chrysanthemi (ELIC) has recently provided structural insight into this family of ion channels at high resolution. The structure shows a homo-pentameric protein with a barrel-stave architecture that defines an ion-conduction pore located on the fivefold axis of symmetry. In this structure, the wide aqueous vestibule that is encircled by the extracellular ligand-binding domains of the five subunits narrows to a discontinuous pore that spans the lipid bilayer. The pore is constricted by bulky hydrophobic residues towards the extracellular side, which probably serve as barriers that prevent the diffusion of ions. This interrupted pore architecture in ELIC thus depicts a non-conducting conformation of a pentameric ligand-gated ion channel, the thermodynamically stable state in the absence of bound ligand. As ligand binding promotes pore opening in these ion channels and the specific ligand for ELIC has not yet been identified, we have turned our attention towards a homologous protein from the cyanobacterium Gloebacter violaceus (GLIC). GLIC was shown to form proton-gated channels that are activated by a pH decrease on the extracellular side and that do not desensitize after activation. Both prokaryotic proteins, ELIC and GLIC form ion channels that are selective for cations over anions with poor discrimination among monovalent cations, characteristics that resemble the conduction properties of the cation-selective branch of the family that includes acetylcholine and serotonin receptors. Here we present the X-ray structure of GLIC at 3.1 A resolution. The structure reveals a conformation of the channel that is distinct from ELIC and that probably resembles the open state. In combination, both structures suggest a novel gating mechanism for pentameric ligand-gated ion channels where channel opening proceeds by a change in the tilt of the pore-forming helices.
Structure of a potentially open state of a proton-activated pentameric ligand-gated ion channel.,Hilf RJ, Dutzler R Nature. 2009 Jan 1;457(7225):115-8. Epub 2008 Nov 5. PMID:18987630[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
- ↑ Hilf RJ, Dutzler R. Structure of a potentially open state of a proton-activated pentameric ligand-gated ion channel. Nature. 2009 Jan 1;457(7225):115-8. Epub 2008 Nov 5. PMID:18987630 doi:10.1038/nature07461
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