Amino Acid Sequence of a Neurotoxic Phospholipase A2 Enzyme From Common Death Adder (Acanthophis antarcticus) Venom

Abstract

The amino acid sequence of the first neurotoxic phospholipase A2, acanthoxin AI, purified from the venom of the Common death adder (Acanthophis antarcticus) was determined. Acanthoxin Al shows high homology with other Australian elapid PLA2 neurotoxins, in particular Acanthin -I and -II, also from Death adder, Pseudexin A from the Red-bellied black snake (Pseudechis porphyriacus), and Pa-I2a and Pa-9c from the King brown snake (Pseudechis australis). Acanthoxin Al is a single-chain 118 amino acid residue PLA2, including 14 half cystine residues and the essential residues forming the ubiquitous calcium binding pocket and catalytic site. Critical analysis of the residues hypothesized to be important for neurotoxicity is presented.