BINDING OF CHIMERIC ANALOGS OF OMEGA-CONOTOXIN MVIIA AND MVIIC TO THEN-TYPE AND P Q-TYPE CALCIUM CHANNELS/

Despite their high sequence homology, the peptide neurotoxins omega-co notoxin MVIIA and MVIIC selectively block N- and P/Q-type calcium chan nels, respectively. To study the recognition mechanism of calcium chan nel subtypes, two chimeric analogs of omega-conotoxin MVIIA and MVIIC were synthesized by exchanging their N- and C-terminal halves. Binding assay for both N- and P/Q-type calcium channels showed that amino aci d residues restricted to the N-terminal half are important for the rec ognition of N-type channels, whereas essential residues for P/Q-type c hannel recognition are widely spread over the whole omega-conotoxin mo lecule. (C) 1997 Federation of European Biochemical Societies.