CECROPIN-A MAGAININ-2 HYBRID PEPTIDES HAVING POTENT ANTIMICROBIAL ACTIVITY WITH LOW HEMOLYTIC EFFECT

In order to obtain peptides having improved antimicrobial activity wit h low hemolytic effect, a hybrid peptide (CA-MA) composed from cecropi n A (1-8) and magainin 2(1-12), and its analogues with amino acid subs titutions were designed and synthesized. The antimicrobial activities against bacterial cells and hemolytic activities against human red blo od cells were analyzed for each peptide. Secondary structures of the p eptides in aqueous solution, 50% trifluoroethanol, and sodium dodecyls ulfate micelles were estimated using circular dichroism spectroscopy. The increase in hydrophobicity or a-helicity of the peptides correlate d with an increase in hemolytic activity rather than antimicrobial act ivity. The substitution of Leu for Ser at position 16 in CA-MA resulte d in a remarkable increase in antimicrobial activity without a signifi cant change in hemolytic activity. Furthermore, the increase in antimi crobial activity of the peptides was not always accompanied by the inc rease in hemolytic activity.