1iiw
From Proteopedia
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|ACTIVITY= | |ACTIVITY= | ||
|GENE= GluR0 slr1257 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1143 Synechocystis sp.]) | |GENE= GluR0 slr1257 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1143 Synechocystis sp.]) | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY=[[1ii5|1II5]], [[1iit|1IIT]] | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1iiw FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1iiw OCA], [http://www.ebi.ac.uk/pdbsum/1iiw PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1iiw RCSB]</span> | ||
}} | }} | ||
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[[Category: membrane protein]] | [[Category: membrane protein]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 21:20:24 2008'' |
Revision as of 18:20, 30 March 2008
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| , resolution 1.90Å | |||||||
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| Gene: | GluR0 slr1257 (Synechocystis sp.) | ||||||
| Related: | 1II5, 1IIT
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
GLUR0 LIGAND BINDING CORE: CLOSED-CLEFT LIGAND-FREE STRUCTURE
Overview
High-resolution structures of the ligand binding core of GluR0, a glutamate receptor ion channel from Synechocystis PCC 6803, have been solved by X-ray diffraction. The GluR0 structures reveal homology with bacterial periplasmic binding proteins and the rat GluR2 AMPA subtype neurotransmitter receptor. The ligand binding site is formed by a cleft between two globular alpha/beta domains. L-Glutamate binds in an extended conformation, similar to that observed for glutamine binding protein (GlnBP). However, the L-glutamate gamma-carboxyl group interacts exclusively with Asn51 in domain 1, different from the interactions of ligand with domain 2 residues observed for GluR2 and GlnBP. To address how neutral amino acids activate GluR0 gating we solved the structure of the binding site complex with L-serine. This revealed solvent molecules acting as surrogate ligand atoms, such that the serine OH group makes solvent-mediated hydrogen bonds with Asn51. The structure of a ligand-free, closed-cleft conformation revealed an extensive hydrogen bond network mediated by solvent molecules. Equilibrium centrifugation analysis revealed dimerization of the GluR0 ligand binding core with a dissociation constant of 0.8 microM. In the crystal, a symmetrical dimer involving residues in domain 1 occurs along a crystallographic 2-fold axis and suggests that tetrameric glutamate receptor ion channels are assembled from dimers of dimers. We propose that ligand-induced conformational changes cause the ion channel to open as a result of an increase in domain 2 separation relative to the dimer interface.
About this Structure
1IIW is a Single protein structure of sequence from Synechocystis sp.. Full crystallographic information is available from OCA.
Reference
Mechanisms for ligand binding to GluR0 ion channels: crystal structures of the glutamate and serine complexes and a closed apo state., Mayer ML, Olson R, Gouaux E, J Mol Biol. 2001 Aug 24;311(4):815-36. PMID:11518533
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