Characterization of the cDNA encoding a BPI/LBP homologue in venom gland of the hundred-pace snake Deinagkistrodon acutus

Abstract

Abstract Bactericidal/permeability-increasing protein (BPI) and LPS-binding protein (LBP) play an important role in host defence. Current evidence shows that BPI/ LBP may be widely existed in different cells and tissue types of animals. A full-length cDNA clone encoding a BPI/LBP homologue (dBPI), 1757 bp in size, was characterized in venom gland of the hundred-pace snake Deinagkistrodon acutus. Its deduced amino acid sequence of 417 residues had 13.8% - 21.5% identity to BPI like 1 (BPILl) and BPI like 3 (BPIL3) of other animals. Conserved cysteine residues which are involved in disulfide bond formation between the final strand of the N-terminal beta sheet and the long alpha helix of BPI are identified as Cysl46-Cysl83 of dBPI. Phylogenetic tree analysis showed that the BPI/LBP homologues formed five large clusters and dBPI was in a large cluster including BPILl and BPIL3. dBPI mRNA shows a tissue specific expression in venom gland. This is the first study to identify the cDNA encoding BPI/LBP homologues from reptiles.