3c35
From Proteopedia
Crystal structure of GluR5 ligand-binding core in complex with cesium at 1.97 Angstrom resolution
Structural highlights
Function[GRIK1_RAT] Ionotropic glutamate receptor. L-glutamate acts as an excitatory neurotransmitter at many synapses in the central nervous system. Binding of the excitatory neurotransmitter L-glutamate induces a conformation change, leading to the opening of the cation channel, and thereby converts the chemical signal to an electrical impulse. The receptor then desensitizes rapidly and enters a transient inactive state, characterized by the presence of bound agonist. May be involved in the transmission of light information from the retina to the hypothalamus.[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 PubMedMembrane 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(+). Molecular basis of kainate receptor modulation by sodium.,Plested AJ, Vijayan R, Biggin PC, Mayer ML Neuron. 2008 Jun 12;58(5):720-35. PMID:18549784[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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