3C34: Crystal Structure Of Glur5 Ligand-binding Core In Complex With Rubidium At 1.82 Angstrom Resolution

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(+).
PDB ID: 3C34Download
MMDB ID: 64981
PDB Deposition Date: 2008/1/27
Updated in MMDB: 2017/11
Experimental Method:
x-ray diffraction
Resolution: 1.82  Å
Source Organism:
Similar Structures:
Biological Unit for 3C34: dimeric; determined by author and by software (PISA)
Molecular Components in 3C34
Label Count Molecule
Proteins (2 molecules)
Glutamate Receptor, Ionotropic Kainate 1(Gene symbol: Grik1)
Molecule annotation
Chemicals (15 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB