1iit
From Proteopedia
| Line 1: | Line 1: | ||
[[Image:1iit.gif|left|200px]] | [[Image:1iit.gif|left|200px]] | ||
| - | + | <!-- | |
| - | + | The line below this paragraph, containing "STRUCTURE_1iit", creates the "Structure Box" on the page. | |
| - | + | You may change the PDB parameter (which sets the PDB file loaded into the applet) | |
| - | + | or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |
| - | + | or leave the SCENE parameter empty for the default display. | |
| - | + | --> | |
| - | + | {{STRUCTURE_1iit| PDB=1iit | SCENE= }} | |
| - | + | ||
| - | + | ||
| - | }} | + | |
'''GLUR0 LIGAND BINDING CORE COMPLEX WITH L-SERINE''' | '''GLUR0 LIGAND BINDING CORE COMPLEX WITH L-SERINE''' | ||
| Line 28: | Line 25: | ||
[[Category: Mayer, M L.]] | [[Category: Mayer, M L.]] | ||
[[Category: Olson, R.]] | [[Category: Olson, R.]] | ||
| - | [[Category: | + | [[Category: Membrane protein]] |
| - | [[Category: | + | [[Category: Same fold as pbp]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 20:03:04 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 17:03, 2 May 2008
GLUR0 LIGAND BINDING CORE COMPLEX WITH L-SERINE
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
1IIT 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 Page seeded by OCA on Fri May 2 20:03:04 2008
