The invention features a polypeptide complex synthesized by bacteria of the genus Clostridia that contains the serotype E botulinum neurotoxin and five neurotoxin associated polypeptides having molecular weights of about 118, 80, 65, 40, and 18 kDa. respectively. The complex is useful in the treatment of diseases or conditions that are caused by excessive release of acetylcholine from presynaptic nerve terminals.