Organization and phylogenetic analysis of kappa-bungarotoxin genes from Bungarus multicinctus (Taiwan banded krait).

Two genomic DNAs were isolated from the liver of Bungarus multicinctus (Taiwan banded krait) encoded kappa1-bungarotoxin and kappa3-bungarotoxin precursors, respectively. They shared virtually identical overall organization with three exons separated by two introns and a high degree of nucleotide-sequence identity with alpha-neurotoxin genes, including similar intron insertions. This suggests that kappa-neurotoxins and alpha-neurotoxins might have originated from a common ancestor.