5b3j
From Proteopedia
Activation of NMDA receptors and the mechanism of inhibition by ifenprodil
Structural highlights
FunctionNMDZ1_XENLA Component of NMDA receptor complexes that function as heterotetrameric, ligand-gated ion channels with high calcium permeability and voltage-dependent sensitivity to magnesium. Channel activation requires binding of the neurotransmitter glutamate to the epsilon subunit, glycine binding to the zeta subunit, plus membrane depolarization to eliminate channel inhibition by Mg(2+) (PubMed:16214956, PubMed:19524674, PubMed:21677647, PubMed:25008524, PubMed:26912815, PubMed:27135925, Ref.11, PubMed:28232581). Sensitivity to glutamate and channel kinetics depend on the subunit composition (Probable).[1] [2] [3] [4] [5] [6] [7] [PDB:5IOV] Publication Abstract from PubMedThe physiology of N-methyl-d-aspartate (NMDA) receptors is fundamental to brain development and function. NMDA receptors are ionotropic glutamate receptors that function as heterotetramers composed mainly of GluN1 and GluN2 subunits. Activation of NMDA receptors requires binding of neurotransmitter agonists to a ligand-binding domain (LBD) and structural rearrangement of an amino-terminal domain (ATD). Recent crystal structures of GluN1-GluN2B NMDA receptors bound to agonists and an allosteric inhibitor, ifenprodil, represent the allosterically inhibited state. However, how the ATD and LBD move to activate the NMDA receptor ion channel remains unclear. Here we applied X-ray crystallography, single-particle electron cryomicroscopy and electrophysiology to rat NMDA receptors to show that, in the absence of ifenprodil, the bi-lobed structure of GluN2 ATD adopts an open conformation accompanied by rearrangement of the GluN1-GluN2 ATD heterodimeric interface, altering subunit orientation in the ATD and LBD and forming an active receptor conformation that gates the ion channel. Activation of NMDA receptors and the mechanism of inhibition by ifenprodil.,Tajima N, Karakas E, Grant T, Simorowski N, Diaz-Avalos R, Grigorieff N, Furukawa H Nature. 2016 May 2. doi: 10.1038/nature17679. PMID:27135925[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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