Primary structure of scorpion anti-insect toxins isolated from the venom of Leiurus quinquestriatus quinquestriatus.
The amino acid sequences of insect-selective scorpion toxins, purified from the venom of Leiurus quinquestriatus quinquestriatus, have been determined by automatic phenyl isothiocyanate degradation of the S-carboxymethylated proteins and derived proteolytic peptides. The excitatory toxin Lqq IT1 and Lqq IT1' (70 residues) show the shift of one half-cystine from an external position, which is characteristic of anti-mammal toxins, to an internal sequence position. Lqq IT2 (61 residues) displays the half-cystine residue in position 12, common to the sequence of all known anti-mammal toxins; it induces flaccid paralysis on insects but is non-toxic for the mouse. Lqq IT2 structurally defines a new type of anti-insect toxins from scorpion venoms. CD spectra and immunological data are in agreement with this finding.
Kopeyan
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Laboratoire de Biochimie-CNRS UA 1179-INSERM U172, Faculté de Médecine, Secteur Nord, Marseille, France.
Mansuelle
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P
Sampieri
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F
Brando
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T
Bahraoui
E M
EM
Rochat
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H
Granier
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C
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D007313:Insecta; D008969:Molecular Sequence Data; D011863:Radioimmunoassay; D012604:Scorpion Venoms / Q000032:analysis* / Q000302:isolation & purification*; D012689:Sequence Homology, Nucleic Acid
D000596:Amino Acids; C063416:Lqq IT1; C063417:Lqq IT2; D012604:Scorpion Venoms