The gene cloning and sequencing of Bm-12, a Chlorotoxin-like peptide from the scorpion Buthus martensi Karsch

According to the known amino acid sequence of Bm-12, a short chain insect n eurotoxin from the venom of the scorpion Buthus martensi Karsch (BmK) with considerable primary sequence homology to chlorotoxin, the gene specific pr imers were designed and synthesized for 3' and 5'RACE (Rapid Amplification of cDNA Ends). The two partial cDNA fragments obtained by 3' and 5'RACE wer e cloned and sequenced, and the full length cDNA sequence of Bm-12 was then completed by overlapping these two partial cDNA sequences. The predicted a mino acid sequence consists of 59 amino acid residues including a putative signal peptide of 24 residues and a mature toxin of 35 residues. The predic ted amino acid sequence of Bm-12 was almost consistent with the determined, different only in one residue at position 27, Lys was replaced by Gly. Bas ed on the determined cDNA sequence, and using the total DNA isolated from t he scorpion venom glands as a template, the genomic DNA of Bm-12 was also a mplified by PCR and sequenced. The genomic DNA sequence revealed an intron of 93 bp present within the signal peptide region, (C) 1999 Elsevier Scienc e Ltd. All rights reserved.