Identification of a novel insecticidal chlorotoxin-like peptide from the venom of the Compsobuthus egyptiensis scorpion.

Scorpion venom contains various bioactive peptides, but there are many scorpion species whose venom has not been studied. The genus Compsobuthus, belonging to the family Buthidae, is relatively diverse, but there have been no reports on their venom components. In the present study, we characterized venom components of the Compsobuthus egyptiensis scorpion inhabiting the northern Egyptian desert. Mass spectrometry analysis of the venom revealed that the components with molecular masses from 3000 to 4000 Da were relatively abundant among 198 components detected. We then isolated a novel insecticidal peptide, Ce-1, from one of the HPLC fractions showing insecticidal activity. The structure of Ce-1 was determined using a combination of Edman degradation and de novo MS/MS sequencing analyses. This revealed that Ce-1 consists of 36 amino acid residues with four disulfide bonds. The deduced structure was confirmed by comparison with the synthetic peptide. Ce-1 shares high sequence homology to chlorotoxin-like peptides, which consist of an α-helix and an antiparallel triple-stranded β-sheet cross-linked by four disulfide bonds. Future research on Ce-1 will contribute to elucidating the mechanism of action of insecticidal chlorotoxin-like peptides.