A peptidylprolyl cis/trans isomerase from Xenopus laevis skin: cloning, biochemical characterization and putative role in the secretion

In amphibian skin secretions, a peptidylprolyl cis/trans isomerase activity was detected. A Xenopus laevis skin cDNA coding for this protein was cloned, sequenced and over-expressed in Escherichia coli. The primary structure of the protein shows extensive similarity with members of the cyclophilin A family. Catalytic parameters of the recombinant protein are similar to those of the human enzyme. The enzymatic activity is inhibited by cyclosporin A. Data suggesting that peptidylprolyl isomerization influences the biological activity of antibacterial peptides of amphibian origin are presented, and its putative role in the defence mechanism discussed.