Cloning and characterization of a cDNA sequence encoding the precursor of a chlorotoxin-like peptide from the Chinese scorpion Buthus martensii Karsch.

A full-length cDNA sequence encoding the precursor of a venom peptide with homology to chlorotoxin (named BmKCT) was isolated from a cDNA library made from the venom glands of the Chinese Scorpion Buthus martensii Karsch. The encoded precursor of BmKCT was 59 amino acid residues long including a signal peptide of 24 residues and a mature toxin of 35 residues with four disulfide bridges. The sequence of BmKCT is similar (68% identities) to that of chlorotoxin isolated from Leiurus quinguestriatus quinquestriatus. BmKCT is the first report of the cDNA sequences encoding four-disulfide-bridged short-chain toxins from Buthus martensuii Karsch so far.