Molecular cloning and evolution of the genes encoding the precursors of taiwan cobra cardiotoxin and cardiotoxin-like basic protein.

Genomic DNAs encoding the precursors of eight cardiotoxins and two cardiotoxin-like basic proteins (CLBP) were isolated from the liver of Naja naja atra (Taiwan cobra). The cardiotoxin and CLBP genes have three exons like alpha-neurotoxin precursors. The promoter regions of these genes are highly conserved and contain the consensus transcriptional factor-binding sites for TBP, NF-1, CACCC-binding site, Spl and EFII, suggesting that these genes are regulated using similar transcriptional mechanisms.

Novel neurotoxins from Taiwan banded krait (Bungarus multicinctus) venom: purification, characterization and gene organization.

Two novel neurotoxins BM10-1 and BM10-2 were isolated from Bungarus multicinctus (Taiwan banded krait) venom using the combinations of chromatography on a SP-Sephadex C-25 column and a reverse phase HPLC column. BM10-1 contained 66 amino acid residues including 10 Cys residues, while BM10-2 consisted of 65 amino acid residues with 8 Cys residues. The secondary structure of both BM10-1 and BM10-2 was dominated with beta-sheet, but their gross conformation differed as evidenced by CD spectra and acrylamide quenching studies.

Muscarinic toxin-like proteins from Taiwan banded krait (Bungarus multicinctus) venom: purification, characterization and gene organization.

Two novel proteins, BM8 and BM14, were isolated from Bungarus multicinctus (Taiwan banded krait) venom using the combination of chromatography on a SP-Sephadex C-25 column and a reverse-phase HPLC column. Both proteins contained 82 amino acid residues including 10 cysteine residues, but there were two amino acid substitutions at positions 37 and 38 (Glu37-Ala38 in BM8; Lys37-Lys38 in BM14). CD spectra and acrylamide quenching studies revealed that the gross conformation of BM8 and BM14 differed.

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.

Characterization and gene organization of Taiwan banded krait (Bungarus multicinctus) gamma-bungarotoxin.

gamma-Bungarotoxin was isolated from Bungarus multicinctus (Taiwan banded krait) venom using a combination of chromatography on a SP-Sephadex C-25 column and a reverse-phase high-performance liquid chromatography column. Circular dichroism (CD) measurement revealed that its secondary structure was dominant with beta-sheet structure as is that of snake venom alpha-neurotoxins and cardiotoxins. gamma-Bungarotoxin exhibits activity on inhibiting the binding of [3H]quinuclidinyl benzilate to the M2 muscarinic acetylcholine receptor subtype, and competes weakly with radioiodinated alpha-bungarotoxin for binding to the Torpedo nicotinic acetylcholine receptor.