1mm6
From Proteopedia
crystal structure of the GluR2 ligand binding core (S1S2J) in complex with quisqualate in a non zinc crystal form at 2.15 angstroms resolution
Overview
Glutamate is the major excitatory neurotransmitter in the mammalian brain. The (S)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazole)propionic acid (AMPA)-subtype glutamate receptor, a ligand-gated ion channel, mediates most of the fast excitatory synaptic transmission in the mammalian central nervous system. Here we present electrophysiological, biochemical, and crystallographic data on the interactions between quisqualate and the GluR2 receptor ion channel and its corresponding ligand binding core. Quisqualate is a high-affinity, full agonist which like AMPA and glutamate elicits maximum peak current responses, and stabilizes the ligand binding core in a fully closed conformation, reinforcing the concept that full agonists produce similar conformational changes [Armstrong, N., and Gouaux, E. (2000) Neuron 28, 165-181]. Nevertheless, the mechanism of quisqualate binding is different from that of AMPA but similar to that of glutamate, illustrating that quisqualate is a faithful glutamate analogue. A detailed comparison of the three agonist complexes reveals distinct binding mechanisms, particularly in the region of a hydrophobic pocket that is proximal to the anionic gamma-substituents, and demonstrates the importance of agonist-water-receptor interactions. The hydrophobic pocket, which is predicted to vary in chemical character between receptor subtypes, probably plays an important role in determining receptor subtype specificity.
About this Structure
1MM6 is a Single protein structure of sequence from Rattus norvegicus. Full crystallographic information is available from OCA.
Reference
Mechanism of activation and selectivity in a ligand-gated ion channel: structural and functional studies of GluR2 and quisqualate., Jin R, Horning M, Mayer ML, Gouaux E, Biochemistry. 2002 Dec 31;41(52):15635-43. PMID:12501192 Page seeded by OCA on Sat May 3 01:24:36 2008
