The ligand-binding domain of the AMPA (alpha-amino-3-hydroxyl-5-methyl-4-isoxazolepropionic acid) subtypes of ionotropic glutamate receptors, a member of the type 2 periplasmic binding fold protein superfamily.
This family represents the ligand-binding domain of the AMPA receptor subunits, a member of non-NMDA (N-methyl-D-aspartate) type iGluRs which are ligand-gated ion channels that mediate excitatory synaptic transmission in the central nervous system. While this ligand-binding domain is structurally homologous to the periplasmic-binding fold type II superfamily, the N-terminal domain of AMPA receptors belongs to the periplasmic-binding fold type I. They consist of four types of subunits (GluR1, GluR2, GluR3, and GluR4) which combine to form a tetramer and play an important role in mediating the rapid excitatory synaptic current.
Jiyao W et al.(2023). "The conserved domain database in 2023.",