Binds with high affinity to muscle nicotinic acetylcholine receptor (nAChR) and hinders acetylcholine binding to the receptor, thereby impairing neuromuscular transmission. Competes with the binding of alpha-bungarotoxin on muscle AChR (from Torpedo) with an IC(50) of 0.30 uM. Causes muscle paralysis, spasms and increased respiration. Expressed by the venom gland. LD(50) is 1 mg/kg by intravenous injection into mice. Belongs to the snake three-finger toxin family. Short-chain subfamily. Type III alpha-neurotoxin sub-subfamily.