World Library  
Flag as Inappropriate
Email this Article


Article Id: WHEBN0000773577
Reproduction Date:

Title: Charybdotoxin  
Author: World Heritage Encyclopedia
Language: English
Subject: Slotoxin, Isopimaric acid, Peripheral membrane protein, Vanillotoxin, Huwentoxin
Collection: Invertebrate Toxins, Ion Channel Toxins, Neurotoxins
Publisher: World Heritage Encyclopedia


Refined model of Charybdotoxin. PDB . [1]
Symbol ChTX
Alt. symbols ChTX-Lq1, ChTx-a
CAS number
PDB 2crd More structures
UniProt P13487
Other data

Charybdotoxin (CTX) is a 37 amino acid neurotoxin from the venom of the scorpion Leiurus quinquestriatus hebraeus (Deathstalker) that blocks calcium-activated potassium channels.[2] This blockade causes hyperexcitability of the nervous system. It is a close homologue of agitoxin and both toxins come from Leiurus quinquestriatus hebraeus.


  • Chemical properties 1
    • Family 1.1
    • Structure 1.2
  • Mode of action 2
  • Treatment 3
  • References 4

Chemical properties


The Charybdotoxin family of scorpion toxins is a group of small peptides that has many family members, such as the Pandinotoxin, derived from the venom of scorpion Pandinus imperator. [3]


Scorpions such as the deathstalker paralyze their prey by injecting a potent mix of peptide toxins.[4] Charybdotoxin, a 37 amino acid, 4 kDa neurotoxin with the molecular formula C176H277N57O55S7, is one of the peptide toxins that can be extracted from the venom of the scorpion. Its structure is very similar to that of margatoxin. Charybdotoxin contains three disulfide bridges.[5]

Mode of action

Charybdotoxin occludes the pore of calcium-activated voltage-gated Shaker K+ channels by binding to one of four independent, overlapping binding sites.[6][7] It binds both to the open and the closed states. In addition, the block is enhanced as the ionic strength is lowered.[8] This block occurs as the Asn 30 on the CTX interacts with the Asp 381 on the K+ channel.[9] The blockade of K+ channels by the charybdotoxin peptide causes neuronal hyperexcitability. Mutations of the Lys31Gln and the Asn30Gln had the effect of lessening the CTX block of the pore on the Shaker channel.[9]


Anti-scorpion venom serum (AScVS) is an effective and safe method of therapy in severe scorpion envenoming syndrome. Compared with other therapies like alpha blockers it has a relatively short recovery period (10 vs 16–42 hours).[10]


  1. ^ Ben-Tal N, Honig B, Miller C, McLaughlin S (October 1997). "Electrostatic binding of proteins to membranes. Theoretical predictions and experimental results with charybdotoxin and phospholipid vesicles". Biophys. J. 73 (4): 1717–27.  
  2. ^ Laurent F, Michel A, Bonnet PA, Chapat JP, Boucard M (March 1993). "Evaluation of the relaxant effects of SCA40, a novel charybdotoxin-sensitive potassium channel opener, in guinea-pig isolated trachealis". Br. J. Pharmacol. 108 (3): 622–6.  
  3. ^ Tenenholz TC, Rogowski RS, Collins JH, Blaustein MP, Weber DJ (1997). "Solution Structure for Pandinus Toxin K-R (PiTX-KR), a Selective Blocker of A-Type Potassium Channels". Biochemistry. 11;36(10): 2763–71.  
  4. ^ Purves D, Augustine GJ, Fitzpatrick D, Hall WC, Lamantia AS, McNamara JO, Williams SM. Neuroscience, p82.
  5. ^ Avdonin V, Nolan B, Sabatier JM, De Waard M, Hoshi T (August 2000). "Mechanisms of maurotoxin action on Shaker potassium channels". Biophys. J. 79 (2): 776–87.  
  6. ^ Thompson J, Begenisich T (May 2000). "Electrostatic interaction between charybdotoxin and a tetrameric mutant of Shaker K(+) channels". Biophys. J. 78 (5): 2382–91.  
  7. ^ Naranjo D, Miller C (January 1996). "A strongly interacting pair of residues on the contact surface of charybdotoxin and a Shaker K+ channel". Neuron 16 (1): 123–30.  
  8. ^ MacKinnon R, Reinhart PH, White MM (December 1988). "Charybdotoxin block of Shaker K+ channels suggests that different types of K+ channels share common structural features". Neuron 1 (10): 997–1001.  
  9. ^ a b Gao YD, Garcia ML (August 2003). "Interaction of agitoxin2, charybdotoxin, and iberiotoxin with potassium channels: selectivity between voltage-gated and Maxi-K channels". Proteins 52 (2): 146–54.  
  10. ^ Natu VS, Murthy RK, Deodhar KP (April 2006). "Efficacy of species specific anti-scorpion venom serum (AScVS) against severe, serious scorpion stings (Mesobuthus tamulus concanesis Pocock)—an experience from rural hospital in western Maharashtra". J Assoc Physicians India 54: 283–7.  
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from World Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.