PCM19

Emerging multidrug-resistant (MDR) bacteria are an enormous threat to human life because of their resistance to currently available antibiotics. The genes encoding antibacterial peptides have been studied extensively and are excellent candidates for a new generation of antibiotic drugs to fight MDR bacteria. In contrast to traditional antibiotics, antibacterial peptides, which do not cause drug resistance, have an unparalleled advantage. However, because most antibacterial peptides originate in species other than humans, the hetero-immunological rejection of antibacterial peptides is a key disadvantage that limits their clinical application. In this study, we identify hGlyrichin as a potential human antibacterial polypeptide. The hGlyrichin polypeptide kills a variety of bacteria including the MDR bacteria methicillin-resistant Staphylococcus aureus, MDR Pseudomonas aeruginosa, and MDR tubercle bacillus. A 19 amino acid peptide (pCM19) at positions 42-60 of hGlyrichin is crucial for its antibacterial activity. The hGlyrichin polypeptide kills bacteria through the destruction of the bacterial membrane. In addition, all peptides that are homologous to hGlyrichin have antibacterial activity and can penetrate the bacterial membrane. Importantly, hGlyrichin does not cause hemolytic side effects in vitro or in vivo. Therefore, based on the virtues of hGlyrichin, i.e., the absence of hetero-immunological rejection and hemolytic side effects and the unambiguous efficacy of killing pathogenic MDR bacteria, we propose hGlyrichin as a potential human antibacterial polypeptide.

Background: hGlyrichin is a novel human antimicrobial peptide rich in glycine. The previous study of known human antimicrobial peptides indicated that in an eligible range, the greater corresponding antibacterial activity was consisted with the shorter peptide sequence. Findings: Two peptides named pCM19 and pCM12 were synthesized and the antibacterial activity assay results showed that these peptides exhibited strong antibacterial activity that was inversely proportional to the length of the peptide. Despite the effective inhibition of bacterial growth, the synthetic peptides showed no hemolytic effect on human red blood cells. Conclusions: Taken together, these two peptides derived from hGlyrichin both have strong antibacterial activity and are not toxic to human somatic cells.