Adaptive evolution in the snake venom Kunitz/BPTI protein family

• Published in: FEBS letters Vol. 547; no. 1; pp. 131 - 136
• Main Authors: Zupunski, Vera, Kordis, Dusan, Gubensek, Franc
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 17.07.2003
• Subjects: Adaptive evolution; Amino Acid Sequence; Animals; Aprotinin - genetics; Base Sequence; BPTI, bovine pancreatic trypsin inhibitor; Btx, bungarotoxin; Chi, chymotrypsin inhibitor; Cloning, Molecular; DNA Primers; DNA, Complementary - genetics; Dtx, dendrotoxin; Evolution, Molecular; Gene Library; Kunitz/BPTI homolog; Molecular Sequence Data; Multigene family; Phylogeny; PLA2, phospholipase A2; Polymerase Chain Reaction; Sequence Alignment; Sequence Homology, Amino Acid; Snake venom; Ti, trypsin inhibitor; Tx, textilinin; Viperidae - classification; Viperidae - genetics; Adaptive evolution; PLA 2, phospholipase A 2; Snake venom; Kunitz/BPTI homolog; BPTI, bovine pancreatic trypsin inhibitor; Tx, textilinin; Multigene family; Chi, chymotrypsin inhibitor; Dtx, dendrotoxin; Btx, bungarotoxin; Ti, trypsin inhibitor
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(03)00693-8

Snake venoms are rich sources of serine proteinase inhibitors that are members of the Kunitz/BPTI (bovine pancreatic trypsin inhibitor) family. However, only a few of their gene sequences have been determined from snakes. We therefore cloned the cDNAs for the trypsin and chymotrypsin inhibitors from a Vipera ammodytes venom gland cDNA library. Phylogenetic analysis of these and other snake Kunitz/BPTI homologs shows the presence of three clusters, where sequences cluster by functional role. Analysis of the nucleotide sequences from the snake Kunitz/BPTI family shows that positive Darwinian selection was operating on the highly conserved BPTI fold, indicating that this family evolved by gene duplication and rapid diversification.