Clostridium tetani produces a potent neurotoxin called tetanus toxin. It is synthesized as a single polypeptide chain with Mr~150 kDa. Later, it undergoes limited proteolysis that generates two fragments: light (Mr~50 kDa) and heavy (Mr~100 kDa) chains. The mature toxin is composed of a heavy and a light chain that are linked via a disulfide bridge. The heavy chain recognizes specific receptors located on neurons and mediates transport of the light chain inside of them. The light chain that corresponds to the N-terminal part of the originally synthesized polypeptide chain is a metalloendoprotease. Inside of neurons, it selectively cleaves synaptobrevin, an integral membrane protein of synaptic vesicles. This cleavage results in inhibition of the release of neurotransmitters from presynaptic nerve endings.
Your IP Address is: 22.214.171.124