CHARACTERIZATION OF MULTIPLE NICOTINIC ACETYLCHOLINE RECEPTOR-BINDINGPROTEIN-A(2) AND PHOSPHOLIPASE-A(2) FROM THE VENOM OF THE CORAL SNAKEMICRURUS-NIGROCINCTUS-NIGROCINCTUS

The presence of multiple nicotinic acetylcholine receptor (AchR)-bindi ng proteins and phospholipases A(2) was detected in the venom of a mem ber of the Elapinae subfamily, Micrurus nigrocinctus nigrocinctus. Mul ti-step chromatographies were used to isolate four AchR-binding protei ns (Mnn-9, Mnn-4, Mnn-3C and Mnn-1A) and five basic PLA(2)s (nigroxins A, B, C1, C2 and C3), The Micrurus as AchR-binding proteins are antig enically and structurally related to short- and long-chain cu-neurotox ins from Naja. The nigroxins are antigenically similar and constitute a new antigenic subclass of PLA(2)s. Nigroxins A and B are class I PLA (2)s, structurally more related to enzymes from Bungarinae than to tho se from Hydrophinae/Laticaudinae. These data contribute to clarify the relationships between Micrurus venom proteins and other elapid toxins and may be useful to improve the neutralizing efficiency of antivenom s.