Charybdotoxin
| Charybdotoxin | |||||||
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UniProt P13487 | | ||||||
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Charybdotoxin (ChTX) is a 37
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. It is named after Charybdis, a sea monster from Greek myth.[3]
Chemical properties
Family
The Charybdotoxin family of scorpion toxins is a group of small peptides that has many family members, such as the
Pandinus imperator.[4]
Structure
Scorpions such as the
disulfide bridges.[6]
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.[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 Asn 30 on the CTX interacts with the Asp 381 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]
Treatment
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).[11]