Tetanospasmin

Tetanospasmin is a neurotoxin produced by the vegetative cell of Clostridium tetani in anaerobic conditions, causing tetanus. It has no known function for clostridia in the soil environment where they are normally encountered. It is also called tetanus toxin.

Structure

Tetanospasmin is composed of a heavy chain (about 100 kDa) and a light chain (about 50 kDa) connected by a disulfide bond. The heavy chain has receptor binding and membrane translocation domains, while the light chain has the protease domain.

Mechanism of action

The toxin binds to peripheral nerve endings, is taken up into the nerves and transported within the axons to the spinal cord. The light chain of the toxin is a zinc endopeptidase which targets synaptobrevin, a protein believed to be involved in the release of neurotransmitters.

Clinical significance

Tetanospasmin causes tetanus, a disease characterized by prolonged contraction of skeletal muscle fibers. The toxin's effect may lead to respiratory failure and, in severe cases, death.

See also

• Tetanus
• Clostridium tetani
• Neurotoxin
• Synaptobrevin

Tetanospasmin Resources
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