Primary structure of scorpion anti-insect toxins isolated from the venom of Leiurus quinquestriatus quinquestriatus.

Abstract

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.

• Authors: C Kopeyan, P Mansuelle, F Sampieri, T Brando, E M Bahraoui, H Rochat, C Granier
• Journal: FEBS letters (FEBS Lett) Vol. 261 Issue 2 Pg. 423-6 (Feb 26 1990) ISSN: 0014-5793 [Print] England
• PMID: 2311768 (Publication Type: Comparative Study, Journal Article)

Chemical References

• Amino Acids
• Lqq IT1
• Lqq IT2
• Scorpion Venoms

Topics

• Amino Acid Sequence
• Amino Acids (analysis)
• Animals
• Chromatography, High Pressure Liquid
• Insecta
• Molecular Sequence Data
• Radioimmunoassay
• Scorpion Venoms (analysis, isolation & purification)
• Sequence Homology, Nucleic Acid