Binds to muscular nicotinic acetylcholine receptor (nAChR) and inhibits acetylcholine from binding to the receptor, thereby potently impairing neuromuscular transmission. Pseudo-irreversibly inhibits the nAChR through competitive antagonism. In contrast to other long-chain alpha-neurotoxins, lacks affinity for neuronal alpha-7 nicotinic acetylcholine receptor. Expressed by the venom gland. Belongs to the snake three-finger toxin family. Long-chain subfamily. Type II alpha-neurotoxin sub-subfamily.