AMPA受体
NMDA受体
化学
天冬酰胺
生物物理学
钙
谷氨酸受体
镁
红藻氨酸受体
谷氨酰胺
生物化学
电压依赖性钙通道
受体
氨基酸
生物
有机化学
作者
Nail Burnashev,Ralf Schoepfer,Hannah Monyer,J. P. Ruppersberg,W. C. Gunther,P. H. Seeburg,Bert Sakmann
出处
期刊:Science
[American Association for the Advancement of Science (AAAS)]
日期:1992-09-04
卷期号:257 (5075): 1415-1419
被引量:414
标识
DOI:10.1126/science.1382314
摘要
The N-methyl-D-aspartate (NMDA) receptor forms a cation-selective channel with a high calcium permeability and sensitivity to channel block by extracellular magnesium. These properties, which are believed to be important for the induction of long-term changes in synaptic strength, are imparted by asparagine residues in a putative channel-forming segment of the protein, transmembrane 2 (TM2). In the NR1 subunit, replacement of this asparagine by a glutamine residue decreases calcium permeability of the channel and slightly reduces magnesium block. The same substitution in NR2 subunits strongly reduces magnesium block and increases the magnesium permeability but barely affects calcium permeability. These asparagines are in a position homologous to the site in the TM2 region (Q/R site) of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors that is occupied by either glutamine (Q) or arginine (R) and that controls divalent cation permeability of the AMPA receptor channel. Hence AMPA and NMDA receptor channels contain common structural motifs in their TM2 segments that are responsible for some of their ion selectivity and conductance properties.
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