The Charybdotoxin family of scorpion toxins is a group of small peptides that has many family members, such as thepandinotoxin, derived from the venom of scorpionPandinus imperator.[4]
Scorpions such as thedeathstalker paralyze their prey by injecting a potent mix of peptide toxins.[5] 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 ofmargatoxin. Charybdotoxin contains threedisulfide bridges.[6]
Charybdotoxin occludes the pore of calcium-activated voltage-gatedshaker K+ channels by binding to one of four independent, overlapping binding sites.[7][8] It binds both to the open and the closed states. In addition, the block is enhanced as the ionic strength is lowered.[9] This block occurs as the Asn30 on the CTX interacts with the Asp381 on the K+ channel.[10] 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.[10]
Anti-scorpion venom serum (AScVS) is an effective and safe method of therapy in severe scorpion envenoming syndrome. Compared with other therapies likealpha blockers it has a relatively short recovery period (10 vs 16–42 hours).[11]
^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.doi:10.1016/0896-6273(88)90156-0.PMID2483094.S2CID44466070.
^abGao 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.doi:10.1002/prot.10341.PMID12833539.S2CID7136604.
^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.PMID16944610.
