Binds with high affinity to muscular (alpha-1/CHRNA1) and neuronal (alpha-7/CHRNA7) nicotinic acetylcholine receptor (nAChR) and inhibits acetylcholine from binding to the receptor, thereby impairing neuromuscular and neuronal transmission. Monomer in solution, homodimer in crystal state. Expressed by the venom gland. Belongs to the snake three-finger toxin family. Long-chain subfamily. Type II alpha-neurotoxin sub-subfamily. PubMed:9837992 indicates that a number of mRNA with sequence conflict(s) are produced by RNA editing. This seems not to be the case as discussed in PubMed:10497260.