Identification of a Novel Cathelicidin from the Deinagkistrodon acutus Genome with Antibacterial Activity by Multiple Mechanisms

The abuse of antibiotics and the consequent increase of drug-resistant bacteria constitute a serious threat to human health, and new antibiotics are urgently needed. Research shows that antimicrobial peptides produced by natural organisms are potential substitutes for antibiotics. Based on Deinagkistrodon acutus (known as five-pacer viper) genome bioinformatics analysis, we discovered a new cathelicidin antibacterial peptide which was called FP-CATH. Circular dichromatic analysis showed a typical helical structure. FP-CATH showed broad-spectrum antibacterial activity. It has antibacterial activity to Gram-negative bacteria and Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA). The results of transmission electron microscopy (TEM) and scanning electron microscopy (SEM) showed that FP-CATH could cause the change of bacterial cell integrity, having a destructive effect on Gram-negative bacteria and inducing Gram-positive bacterial surface formation of vesicular structure. FP-CATH could bind to LPS and showed strong binding ability to bacterial DNA. In vivo, FP-CATH can improve the survival rate of nematodes in bacterial invasion experiments, and has a certain protective effect on nematodes. To sum up, FP-CATH is likely to play a role in multiple mechanisms of antibacterial action by impacting bacterial cell integrity and binding to bacterial biomolecules. It is hoped that the study of FP-CATH antibacterial mechanisms will prove useful for development of novel antibiotics.