Objective: The amphipathic alpha-helical peptide is an important class of antimicrobial peptides. In this study, a 16-residue-long peptide (VGR16) composed of 8 Val residues in the nonpolar face and 5 Arg residues in the polar face was designed based on the helical wheel projection to produce antimicrobial peptide with improved antibacterial activity accompanied by decreased toxicity.
Methods: Antimicrobial activity and toxicity against red blood cells and mammalian cells were investigated to evaluate the biological function of the peptide. In addition, bactericidal kinetics was tested.
Results: Antimicrobial assays revealed that the peptide VGR16 showed antimicrobial activity and their MICs against gram-negative and gram-positive bacteria ranged from 16 microg/ml to 64 microg/ml. VGR16 also exhibited rapid bactericidal action. It was surprisingly found that the peptide displayed no hemolytic activity even at a concentration of 256 microg/ml. Cell culture assays indicated that the peptide VGR16 had low cytotoxicity against mammalian cells.
Conclusion: The results showed that the peptide could be a likely candidate for future antimicrobial applications.