A PROTEASE-RESISTANT NOVEL HEMAGGLUTININ PURIFIED FROM TYPE-A CLOSTRIDIUM-BOTULINUM

Botulinum neurotoxin is a food poisoning agent produced by Clostridium botulinum. The neurotoxin is a 150-kDa protein that causes flaccid mu scle paralysis by blocking neurotransmitter release at neuromuscular j unctions. The neurotoxin is produced along with a group of neurotoxin associated proteins (NAPs), which protect it from the low pH and prote ases of the gastrointestinal (GI) tract. We have isolated, for the fir st time, one of the major components of NAPs in a pure form. The isola ted protein is a 33-kDa single polypeptide (Hn-33) that exhibits hemag glutination activity. Specific polyclonal antibodies against the Hn-33 are able to block the hemagglutination activity of the neurotoxin com plex, which indicates that perhaps Hn-33 is the only strong hemaggluti nating protein in the complex. The Hn-33 was found be resistant to try psin and other protease digestion, a feature that could play a role in the protection of the neurotoxin in the GI tract during its toxicoinf ection.