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Sequence and electrophysiological characterization of two insect‐selective excitatory toxins from the venom of the Chinese scorpion Buthus martensi
Author(s) -
Escoubas Pierre,
Stankiewicz Maria,
Takaoka Tomoyo,
Pelhate Marcel,
Romi-Lebrun Régine,
Wu Fang Qi,
Nakajima Terumi
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)02099-8
Subject(s) - scorpion , venom , scorpion venoms , electrophysiology , insect , patch clamp , voltage clamp , biology , cockroach , pharmacology , chemistry , toxicology , biochemistry , neuroscience , botany , ecology
The two insecticidal peptides Bm32‐VI and Bm33‐I, isolated from the venom of the Chinese scorpion Buthus martensi induce paralytical symptoms typical of insect contractive toxins. They show, respectively, 74% and 77% homology with AaIT from Androctonus australis , comparable insecticidal activity and no vertebrate toxicity. Under voltage‐clamp conditions, both toxins induced (1) an increased fast Na + current, (2) a shift in voltage dependence of Na + current activation, (3) the occurrence of a delayed current, and (4) a slow development of a holding current. Increased Na + conductance at negative potential values is responsible for axonal hyperexcitability and the contractive paralysis of insect prey.