General Information
- 37 amino acid neurotoxin from the venom of the Deathstalker scorpion that blocks calcium-activated potassium channels.
- Could potentially be part of a "superfamily" of proteins that modify ion-channel activities because it is so similar in structure to other toxins.
- Treated with anti-scorpion venom.
![Picture](/uploads/4/9/6/7/49674333/298559379.jpg?250)
Mechanism of Action
- Charybdotoxin is injected into the body by a sting.
- The toxin has a high affinity for potassium channels, where it will bind to prevent binding of potassium.
- Charybdotoxin (CTX) is very sensitive to Shaker potassium channels.
- A Shaker K+ voltage-gated channel has four subunits and is responsible for creating the pore for K+ to pass through.
- It also contains a number of histidine molecules (3).
- The toxin itself has seven positively charged amino acids that are responsible for binding to the Shaker channel.
- Lowering the pH will prevent the toxin from binding to the Shaker channel at all. (4)
- Changing a single histidine molecule on the channel itself also prevents Charybdotoxin from binding.
![Picture](/uploads/4/9/6/7/49674333/1428879446.png)
- Charybdotoxin prevents organs from utilizing substrates present in the body, which can result in organ failure and death.
- Fatality may be a result of cardiovascular failure due to pulmonary edema or respiratory arrest.
- The heart and blood vessels are extremely sensitive to vasoactive substances that are present in large amounts in the venom.
Medical Use
Charybdotoxin has been used to characterize different receptor proteins involved in normal ion channel functioning. Researchers are able to mutate the channel and look at how the toxin will affect the channel (excitation, water balance, hormone secretion, etc.). (2)
Charybdotoxin has been used to characterize different receptor proteins involved in normal ion channel functioning. Researchers are able to mutate the channel and look at how the toxin will affect the channel (excitation, water balance, hormone secretion, etc.). (2)
By: Alexa Kellett
1. Anderson, A.J., A.L. Harvey, E.G. Rowan, and P.N. Strong. "Effects of Charybdotoxin, a Blocker of Ca2+-activated K+ Channels, on Motor Nerve Terminals." British Journal Of Pharmacology 95.4 (1988): 1329-335. Web. 12 Apr. 2015. <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1854283/pdf/brjpharm00281-0328.pdf>.
2. Petricevich, Vera L. "Scorpion Venom and the Inflammatory Response." Scorpion Venom and the Inflammatory Response. N.p., 4 Jan. 2010. Web. 12 Apr. 2015. (http://www.hindawi.com/journals/mi/2010/903295/)
3. "Shaker Gene." Wikipedia. Wikimedia Foundation, n.d. Web. 12 Apr. 2015.
4. Thompson, Jill, and Ted Bengenisich. "Electrostatic Interaction between Charybdotoxin and a Tetrameric Mutant of Shaker K1 Channels." Biophysical Journal 78 (2000): 2382-391. Web. 12 Apr. 2015. <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1300827/pdf/10777734.pdf>.
1. Anderson, A.J., A.L. Harvey, E.G. Rowan, and P.N. Strong. "Effects of Charybdotoxin, a Blocker of Ca2+-activated K+ Channels, on Motor Nerve Terminals." British Journal Of Pharmacology 95.4 (1988): 1329-335. Web. 12 Apr. 2015. <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1854283/pdf/brjpharm00281-0328.pdf>.
2. Petricevich, Vera L. "Scorpion Venom and the Inflammatory Response." Scorpion Venom and the Inflammatory Response. N.p., 4 Jan. 2010. Web. 12 Apr. 2015. (http://www.hindawi.com/journals/mi/2010/903295/)
3. "Shaker Gene." Wikipedia. Wikimedia Foundation, n.d. Web. 12 Apr. 2015.
4. Thompson, Jill, and Ted Bengenisich. "Electrostatic Interaction between Charybdotoxin and a Tetrameric Mutant of Shaker K1 Channels." Biophysical Journal 78 (2000): 2382-391. Web. 12 Apr. 2015. <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1300827/pdf/10777734.pdf>.