Purification and partial characterization of a 'short' insectotoxin-like peptide from the venom of the scorpion Parabuthus schlechteri

A disulfide-rich, low-molecular-mass toxin-like peptide has been isolated f rom Parabuthus schlechteri venom using gel filtration, ion exchange, and re versed phase chromatography, Partial characterization of this peptide revea ls a relationship with four-disulfide bridge proteins belonging to the fami ly of 'short' insectotoxins (44% residue identity). In recognition hereof, the peptide,vas named PBITx1 (sITx10), Our work also reports on the deduced sequences of two other 'short' insectotoxins from Buthus eupeus, I-3 and I -4, and it provides a consensus sequence and nomenclature for all known 'sh ort' insectotoxins. Finally, sequence similarities with K+ channel blockers (charybdotoxin, kappa-conotoxin), and a Cl- channel blocker (chlorotoxin) are highlighted. (C) 1998 Federation of European Biochemical Societies.