Design and Characterization of a Novel Hybrid Antimicrobial Peptide OM19R Based on Oncocin and MDAP-2

Proline-rich antimicrobial peptides (PR-AMPs) have attracted much interest as they target Gram-negative and do not act by lytic mechanisms. In this study, a novel hybrid peptide OM19R was designed based on the Oncocin and MDAP-2. OM19R showed specific and improved potency against Escherichia coli ( E. coli ), Salmonella and Shigella standard strains compared to parental peptides. The minimum inhibitory concentrations (MICs) ranged from 1 to 2 μM. However, the activity against Klebsiella pneumoniae ( K. pneumoniae ) was inhibited. The dependence of the SbmA protein for OM19R activity was also studied by a gene-knockout strain. The confocal laser scanning microscopy further revealed that OM19R could rapidly penetrate into E. coli cells without membrane damage. In summary, the hybrid peptide OM19R is a strong cell-selective antibacterial peptide and a promising specific antibacterial agent.