Charybdotoxin

Overview

Structure of Charybdotoxin

Charybdotoxin is a peptide toxin derived from the venom of the Leiurus quinquestriatus, commonly known as the deathstalker scorpion. It is a potent inhibitor of certain types of potassium channels, particularly the voltage-gated potassium channels and calcium-activated potassium channels.

Structure

Charybdotoxin is a small peptide consisting of 37 amino acids. It has a molecular weight of approximately 4 kDa. The structure of charybdotoxin is stabilized by three disulfide bridges, which are crucial for its biological activity. The three-dimensional structure of charybdotoxin, as determined by X-ray crystallography, reveals a compact, globular shape.

Mechanism of Action

Charybdotoxin exerts its effects by binding to the outer vestibule of potassium channels, blocking the flow of potassium ions through the channel. This blockade alters the electrical activity of the cell, which can affect various physiological processes such as muscle contraction and neurotransmitter release. The toxin is highly selective for certain subtypes of potassium channels, making it a valuable tool for studying channel function.

Biological Significance

Charybdotoxin binding site on potassium channel

Charybdotoxin is used extensively in research to understand the role of potassium channels in cellular physiology. Its ability to selectively inhibit specific potassium channels allows researchers to dissect the contributions of these channels to cellular processes. Additionally, charybdotoxin and its derivatives are being investigated for potential therapeutic applications, particularly in the treatment of diseases involving dysregulated potassium channel activity.

Related Toxins

Charybdotoxin is part of a family of scorpion toxins that target ion channels. Other members of this family include maurotoxin, iberiotoxin, and agitoxin. These toxins share structural similarities and often have overlapping channel specificities, but each has unique properties that make them useful for different research applications.

Related Pages

• Potassium channel
• Ion channel
• Scorpion venom
• Neurotoxin