RECOMBINANT EXPRESSION OF THE ANTIMICROBIAL PEPTIDE POLYPHEMUSIN AND ITS ACTIVITY AGAINST THE PROTOZOAN OYSTER PATHOGEN PERKINSUS-MARINUS

Polyphemusin is a broad-spectrum antimicrobial peptide is elated from hemocytes of the North American horseshoe crab Limulus polyphemus. To date the polyphemusin used for scientific analyses has been purified f rom natural materials or obtained by chemical synthesis. We report her e the recombinant expression in Escherichia coli, and subsequent purif ication, of a polyphemusin analogue (rLim1). To prevent toxicity of th e antimicrobial peptide in the highly susceptible E. colihost, we used a carboxyterminal fusion protein cloning strategy provided by a malto se-binding protein (MBP) gene fusion system (New England Biolabs). Ant imicrobial activity of recombinant polyphemusin was similar to that se en With amidated native polyphemusin peptide. When rLim1 was tested fo r antibiotic activity against the apicomplexan protozoan oyster pathog en Perkinsus marinus, complete inhibition was observed at 12 mu g/ml, and partial inhibition at 8 mu g/ml.