4UQQ: Electron Density Map Of Gluk2 Desensitized State In Complex With 2s, 4r-4-methylglutamate

Ionotropic glutamate receptors are ligand-gated ion channels that mediate excitatory synaptic transmission in the vertebrate brain. To gain a better understanding of how structural changes gate ion flux across the membrane, we trapped rat AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) and kainate receptor subtypes in their major functional states and analysed the resulting structures using cryo-electron microscopy. We show that transition to the active state involves a 'corkscrew' motion of the receptor assembly, driven by closure of the ligand-binding domain. Desensitization is accompanied by disruption of the amino-terminal domain tetramer in AMPA, but not kainate, receptors with a two-fold to four-fold symmetry transition in the ligand-binding domains in both subtypes. The 7.6 A structure of a desensitized kainate receptor shows how these changes accommodate channel closing. These findings integrate previous physiological, biochemical and structural analyses of glutamate receptors and provide a molecular explanation for key steps in receptor gating.
PDB ID: 4UQQDownload
MMDB ID: 122446
PDB Deposition Date: 2014/6/24
Updated in MMDB: 2014/10
Experimental Method:
electron microscopy
Resolution: 7.6  Å
Source Organism:
Similar Structures:
Biological Unit for 4UQQ: tetrameric; determined by author and by software (PISA)
Molecular Components in 4UQQ
Label Count Molecule
Proteins (4 molecules)
Glutamate Receptor Ionotropic, Kainate 2(Gene symbol: Grik2)
Molecule annotation
Chemicals (4 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB