The ligand-binding domain of the NR3 subunit of ionotropic NMDA (N-methyl-D-aspartate) glutamate receptors, a member of the type 2 periplasmic binding fold protein superfamily.
This group contains the ligand-binding domain of the NR3 subunit of NMDA receptor family. The ionotropic N-methyl-d-asparate (NMDA) subtype of glutamate receptors serves critical functions in neuronal development, functioning, and degeneration in the mammalian central nervous system. The functional NMDA receptor is a heterotetramer composed of two NR1 and two NR2 (A, B, C, and D) or of NR3 (A and B) subunits. The receptor controls a cation channel that is highly permeable to monovalent ions and calcium and exhibits voltage-dependent inhibition by magnesium. Dual agonists, glutamate and glycine, are required for efficient activation of the NMDA receptor. Among NMDA receptor subtypes, the NR2B subunit containing receptors appear particularly important for pain perception; thus NR2B-selective antagonists may be useful in the treatment of chronic pain.