6irg
Structure of the human GluN1/GluN2A NMDA receptor in the glutamate/glycine-bound state at pH 6.3, Class II
Structural highlights
DiseaseNMDZ1_HUMAN Defects in GRIN1 are the cause of mental retardation autosomal dominant type 8 (MRD8) [MIM:614254. Mental retardation is characterized by significantly below average general intellectual functioning associated with impairments in adaptative behavior and manifested during the developmental period.[1] FunctionNMDZ1_HUMAN NMDA receptor subtype of glutamate-gated ion channels with high calcium permeability and voltage-dependent sensitivity to magnesium. Mediated by glycine. This protein plays a key role in synaptic plasticity, synaptogenesis, excitotoxicity, memory acquisition and learning. It mediates neuronal functions in glutamate neurotransmission. Is involved in the cell surface targeting of NMDA receptors (By similarity). Publication Abstract from PubMedN-methyl-D-aspartate (NMDA) receptors are critical for synaptic development and plasticity. While glutamate is the primary agonist, protons can modulate NMDA receptor activity at synapses during vesicle exocytosis by mechanisms that are unknown. We used cryo-electron microscopy to solve the structures of the human GluN1-GluN2A NMDA receptor at pH 7.8 and pH 6.3. Our structures demonstrate that the proton sensor predominantly resides in the N-terminal domain (NTD) of the GluN2A subunit and reveal the allosteric coupling mechanism between the proton sensor and the channel gate. Under high-pH conditions, the GluN2A-NTD adopts an "open-and-twisted" conformation. However, upon protonation at the lower pH, the GluN2A-NTD transits from an open- to closed-cleft conformation, causing rearrangements between the tetrameric NTDs and agonist-binding domains. The conformational mobility observed in our structures (presumably from protonation) is supported by molecular dynamics simulation. Our findings reveal the structural mechanisms by which protons allosterically inhibit human GluN1-GluN2A receptor activity. Structural Basis of the Proton Sensitivity of Human GluN1-GluN2A NMDA Receptors.,Zhang JB, Chang S, Xu P, Miao M, Wu H, Zhang Y, Zhang T, Wang H, Zhang J, Xie C, Song N, Luo C, Zhang X, Zhu S Cell Rep. 2018 Dec 26;25(13):3582-3590.e4. doi: 10.1016/j.celrep.2018.11.071. PMID:30590034[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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