Beta-bungarotoxin

Beta-bungarotoxin is a potent neurotoxin found in the venom of the many-banded krait (Bungarus multicinctus), a species of venomous snake native to much of East and Southeast Asia. This toxin is a type of bungarotoxin, a group of neurotoxic proteins that are known for their ability to block neuromuscular transmission, leading to paralysis and potentially death.

Structure and Function

Beta-bungarotoxin is a protein composed of two chains, A and B, linked by disulfide bonds. The A chain is a phospholipase A2, which has the ability to cleave phospholipids, disrupting cell membranes and leading to cell death. The B chain is a Kunitz-type protease inhibitor, which can inhibit various proteases, preventing the breakdown of proteins and peptides in the body.

The toxin works by binding to the acetylcholine receptors at the neuromuscular junction, blocking the transmission of nerve impulses and leading to paralysis. This is a similar mechanism to that of other well-known neurotoxins, such as botulinum toxin and tetanus toxin.

Clinical Significance

Envenomation by the many-banded krait can lead to severe symptoms, including paralysis, respiratory failure, and death. The presence of beta-bungarotoxin in the venom makes it particularly dangerous. Antivenom is available and can be effective if administered promptly.

Beta-bungarotoxin is also of interest in medical research, particularly in the study of neuromuscular diseases and conditions such as myasthenia gravis and Lambert-Eaton syndrome. Its ability to block neuromuscular transmission can provide valuable insights into the workings of these diseases.

The many-banded krait (Bungarus multicinctus), a source of beta-bungarotoxin.

See Also

• Alpha-bungarotoxin
• Bungarotoxin
• Neurotoxin
• Venomous snake