Fasciculin

Fasciculin is a neurotoxin found in the venom of certain species of snake, specifically the Green Mamba (Dendroaspis angusticeps). It is a small protein composed of 61 amino acids and has a molecular weight of approximately 7 kDa. Fasciculin acts by inhibiting acetylcholinesterase, an enzyme that breaks down acetylcholine in the synaptic cleft, thereby prolonging the action of this neurotransmitter and leading to symptoms of poisoning.

Structure

Fasciculin is a single-chain polypeptide that is cross-linked by four disulfide bonds. The protein has a compact, globular structure, with a hydrophobic core surrounded by a hydrophilic surface. The active site of the toxin, which interacts with acetylcholinesterase, is located in a shallow groove on the protein surface.

Mechanism of action

Fasciculin acts by binding to acetylcholinesterase and inhibiting its activity. This prevents the breakdown of acetylcholine, a neurotransmitter that transmits signals in the nervous system. As a result, acetylcholine accumulates in the synaptic cleft, leading to overstimulation of the postsynaptic neuron. This can result in symptoms such as muscle weakness, paralysis, and in severe cases, respiratory failure.

Clinical significance

Due to its potent neurotoxic effects, fasciculin has been the subject of extensive research in the field of neuroscience and toxicology. It has potential applications in the development of drugs for the treatment of neurological disorders such as Alzheimer's disease and myasthenia gravis, which are characterized by impaired acetylcholine signaling.

See also

• Snake venom
• Neurotoxin
• Acetylcholinesterase

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