3c32 image
Deposition Date 2008-01-27
Release Date 2008-06-17
Last Version Date 2024-10-16
Entry Detail
PDB ID:
3C32
Title:
Crystal structure of GluR5 ligand-binding core in complex with sodium at 1.72 Angstrom resolution
Biological Source:
Source Organism:
Rattus norvegicus (Taxon ID: )
Host Organism:
Method Details:
Experimental Method:
Resolution:
1.72 Å
R-Value Free:
0.19
R-Value Work:
0.16
R-Value Observed:
0.16
Space Group:
P 41 21 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:GLUTAMATE RECEPTOR, IONOTROPIC KAINATE 1
Gene (Uniprot):Grik1
Chain IDs:A, B
Chain Length:258
Number of Molecules:2
Biological Source:Rattus norvegicus
Primary Citation
Molecular basis of kainate receptor modulation by sodium.
Neuron 58 720 735 (2008)
PMID: 18549784 DOI: 10.1016/j.neuron.2008.04.001

Abstact

Membrane proteins function in a polarized ionic environment with sodium-rich extracellular and potassium-rich intracellular solutions. Glutamate receptors that mediate excitatory synaptic transmission in the brain show unusual sensitivity to external ions, resulting in an apparent requirement for sodium in order for glutamate to activate kainate receptors. Here, we solve the structure of the Na(+)-binding sites and determine the mechanism by which allosteric anions and cations regulate ligand-binding dimer stability, and hence the rate of desensitization and receptor availability for gating by glutamate. We establish a stoichiometry for binding of 2 Na(+) to 1 Cl(-) and show that allosteric anions and cations bind at physically discrete sites with strong electric fields, that the binding sites are not saturated in CSF, and that the requirement of kainate receptors for Na(+) occurs simply because other cations bind with lower affinity and have lower efficacy compared to Na(+).

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