cDNA sequence analysis and expression of alpha-bungarotoxin from Taiwan banded krait (Bungarus multicinctus).

The cDNA encoding alpha-bungarotoxin (alpha-BuTx) was constructed from the cellular RNA isolated from the venom glands of Bungarus multicintus by RT-PCR. The primers deduced from the N-, C-terminal amino acid residues and the conserved middle segment of the sequence, i.e., R25KMWC29 in alpha-BuTx could specifically amplify cDNAs encoding amino acid residues from 1 to 29 and 25 to 74 of alpha-BuTx. The complete cDNA was obtained by linking sufficient amounts of the two cDNA fragments by PCR. The amino acid sequence translated from the alpha-BuTx cDNA sequence was identical to that of native toxin. The PCR product was then cloned into pGEX vector and transformed in DH5 E. coli strain. The fused protein expressed in host strain exhibited the same antigenicity as native alpha-BuTx. This communication is the first report for the cloning and expression of a long alpha-neurotoxin from the venom glands.