Partial purification of acetylcholine receptor binding components from the Duvernoy's secretions of blanding's tree snake (Boiga blandingi) and the mangrove snake (Boiga dendrophila).

Abstract

Acetylcholine receptor (AChR) binding activity was detected in Duvernoy's secretions from B. blandingi and B. dendrophila as they competitively inhibited formation of 3[H]bungarotoxin-acetylcholine receptor complexes (3[H]Bgt-AChR) in a concentration-dependent manner. Secretions contained two types of toxin: low affinity and high affinity. Reversed-phase HPLC of B. blandingi and B. dendrophila secretions afforded 20 and 14 peaks, respectively. AChR binding components, as revealed by SDS-PAGE, had apparent molecular weights of 10 and 11 kDa (B. blandingi) or 11 and 12 kDa (B. dendrophila). Periodic acid-Schiff staining indicated these were not glycoproteins. Alkylation with 4-vinylpyridine significantly decreased their ability to inhibit 3[H]Bgt-AChR binding, indicating disulphide bridges were necessary for receptor-binding activity. Attempts to sequence the B. blandingi peptides were negative as these components seemed to be N-terminally blocked.