CDNA Sequence Analysis and Expression of κ-Bungarotoxin from Taiwan Banded Krait

Abstract

The cDNAs encoding κ-bungarotoxin was constructed from the cellular RNA isolated from the venom glands ofBungarus multicinctusby reverse transcription-polymerase chain reaction. A high degree of nucleotide sequence homology was observed between κ-bungarotoxin and other κ-neurotoxins. The κ-bungarotoxin was subcloned into the expression vector pET32a(+) and transformed into BL21(DE3)E. colistrain. The recombinant toxin was expressed as a fusion protein. Recombinant κ-bungarotoxin was separated from the fused protein by cleavage with CNBr and purified by reversed phase high performance liquid chromatography. In addition to κ-bungarotoxin, the cDNA fragment encoding κ3-bungarotoxin was also found in the cDNA mixtures prepared from the cellular RNA of the venom glands of the same snake. This result suggests that the venom glands of TaiwaneseB. multicinctusshould secrete at least two kinds of κ-neurotoxins.