[Cloning and characterization of cDNAs of cardiotoxin-like protein in Bungarus multicinctus venom gland].

The venom of elapid snakes contains a number of small proteins that display a broad spectrum of pharmacological activities. In study on the neurotoxin from the venom gland of Bungarus multicinctus, five cDNA sequences (MNCTL1-a,MNCTL1-b,MNCTL1-c,MNCTL1-d and MNCTL2) encoding two novel proteins were obtained from the total RNA by reverse transcription-polymerase chain reaction. Among them, four sequences (MNCTL1-b,MNCTL1-c,MNCTL1-d and MNCTL2) are at the length of 505 bp, composing of a 32 bp 5'-untranslational region,a 212 bp 3'-untranslational region, and a 261 bp open reading frame which encodes a 20 amino acids of signal peptide and a 65 amino acids of mature peptide. But the sequence of MNCTL1-a has only 481 bp because of a 24 bp deletion in 3'-untranslational region. Comparison between cDNA sequences obtained here and that of cardiotoxin-like protein reported by Chang previously shows a homological value above 95.8%. Computer simulation based on deduced amino acid sequences reveals that both proteins encoded by these cDNAs and cardiotoxin-like protein share similar molecular characters, suggesting their functional similarity. This result implies that multicopy genes existing in the genome of Bungarus multicinctus encode cardiotoxin-like proteins.