[Structural characteristics of the recognition site of cholinergic ligands of the nicotinic acetylcholine receptor from squid optic ganglia].

The effect of chemical modification on the binding of cholinergic ligands to nicotinic acetylcholine receptor from squid optical ganglion was studied. The existence of two chemically distinct subpopulations of binding sites was postulated. Subpopulation I contains, in all probability, Arg, Tyr and carboxyl groups critical for the binding of both ligands. Subpopulation II differs from the first one in the amino group present instead of Arg. The amino group important for the binding of d-tubocurarine alone was found in both subpopulations. The data obtained allow one to construct a model of nicotinic acetylcholine receptor cholinergic ligand recognition sites.