Abstract
Antimicrobial peptides (AMPs) are native and safe short peptides that are considered one of the best alternatives to antibiotics. Although numerous studies have been conducted on AMPs, their mode of action has not yet been fully understood. Computational peptide engineering can provide valuable insight into the stability and potency of AMPs against targets. In the present study, we performed a molecular dynamics simulation to understand the mode of action of Bovine Lfcin and to improve the interactions between Bovine Lfcin (wild and mutant types) and DNA (an important intracellular target), DNAK (an important protein in pathogenicity, mostly in gram-negative bacteria), and LysM (an important surface protein in gram-positive bacteria). The nucleotide sequence of Lfcin peptide was synthesized and cloned into pET22b (+). Induction of gene expression was performed using 1mM IPTG and recombinant peptide was purified using a His-tag marker. The antimicrobial peptide activity was tested on Escherichia coli O157 and Bacillus subtilis, Gram- negative and positive bacteria, respectively, using disk diffusion methods. Our results showed that all the changes in the Bovine Lfcin wild type observed in this study improved the peptide-DNA, DNAK, and LysM interactions. Based on the results, removing the PHE25 residue from the wild- type Bovine Lfcin peptide had more significant effects on complex formation with DNA, DNAK, and LysM. The recombinant production of an Lfcin peptide with a molecular weight of ~5 KDa was confirmed by SDS PAGE. The performance of Lfcin peptide on pathogenic bacteria was strong, and it had the strongest effect at concentrations of 6 and 8 mg/ml for Gram- positive and Gram-negative bacteria, respectively.