Determination of NMDA NR1 subunit copy number in recombinant NMDA receptors.
Co-expression of wild-type and mutated NMDA NR1 (N598R) subunits in Xenopus oocytes has been used to determine the stoichiometry of the NMDA receptor-channel. When expressed together, wild-type NR2A and mutant NR1 (N598R) subunits produced channels with a main conductance of 2.6 pS and a sublevel of 1.2 pS. These conductances were clearly different from those obtained from wild-type NR1 and wild-type NR2A channels which gave characteristic 50 pS events with a 40 pS sublevel. When wild-type and mutant NR1 subunits were co-expressed together with NR2A subunits a different channel type with a main conductance of 15.2 pS and a sublevel of 11.4 pS was obtained, as well as the 'all wild-type' and 'all mutant' channels described above. These results indicate that there are likely to be two copies of the NR1 subunit in each NMDA receptor complex.
Béhé
P
P
Department of Pharmacology, University College London, U.K.
Stern
P
P
Wyllie
D J
DJ
Nassar
M
M
Schoepfer
R
R
Colquhoun
D
D
D000818:Animals; D018698:Glutamic Acid / Q000378:metabolism*; D009154:Mutation; D017433:Protein Structure, Secondary; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014981:Xenopus
D016194:Receptors, N-Methyl-D-Aspartate; D011994:Recombinant Proteins; D018698:Glutamic Acid