Expression of Extracellular N-Terminal Domain of NMDA Receptor in Mammalian Cells

NMDA receptor is a ligand-gated ion channel receptor composed of multiple subunits encoded by at least five genes and their splice variants (1 ). Functional channels can be produced with only the NR1 subunit. These single-subunit channels, exhibit many of the key properties found in native channels including the direct permeability of calcium, voltage-dependent Mg²⁺ blockade of the ion channel, and binding sites for modulators, such as Zn²⁺ , glycine, and polyamines (2 ). The NR1 subunit consists of two functionally distinct regions: a large amino-terminal extracellular domain containing the putative agonist binding site and a hydrophobic core consisting of four transmembrane-spanning domains that participate in the formation of the ion-conducting pathway.