Studies on the subunit structure of textilotoxin, a potent neurotoxin from the venom of the Australian common brown snake ( Pseudonaja textilis)

Abstract

Textilotoxin is a presynaptic neurotoxin from the venom of the Australian common brown snake, Pseudonaja textilis. It has the highest lethality and is structurally the most complex of any known snake venom nuerotoxin. It was resolved into its five non-covalently linked subunits in a single step by reverse-phase HPLC. Two of the subunits were identical. The N-terminal amino-acid sequence and amino-acid composition of each subunit were determined. Subunit A was the only one found to possess phospholipase A activity. Separation of textilotoxin into its subunits was reversible and reformed textilotoxin had the same M r and lethality in mice as the native toxin. Experiments with various unnatural combinations of subunits have led to interesting variations in lethality and M r of the resulting complexes.