Molecular cloning and sequence analysis of cDNA encoding haemorrhagic toxin acutolysin A from Agkistrodon acutus

By means of reverse transcription polymerase chain reaction, a full-length cDNA of 1632 bp is amplified from the snake venom gland total RNA of Agkistrodon acutus. Analysis of the nucleotide sequence indicates that the amplified cDNA contains a complete open reading frame encoding 413 amino acid residues including signal peptide sequence, zymogen sequence and proteinase domain. The zymogen sequence contains PKMCGVT motif which is highly conserved in almost all venom metalloproteinases. The metalloproteinase domain contains the conserved signature zinc-binding motif HEXXHXXGXXH in the catalytic region. The predicted amino acid sequence of the metalloproteinase domain is identical to the crystallographic sequence of acutolysin A and also shares high homology with other class I snake venom haemorrhagic toxins.