A Bioinformatics Analysis of Antibacterial Peptides in Five Species of Prokaryote and Eukaryote and the Evaluation of Antibacterial Effects of Nisin on Gram-positive and Gram-negative Bacteria

Abstract

Introduction: Nowadays, the widespread use of antimicrobial peptides as a natural preservative due to the side effects of synthetic preservatives (cancers and liver damages in medicines and foods) has received much attention. Materials and methods: In the present study, five antibacterial peptides including Nisin A of Lactococcus lactis, melitin of Apis mellifera, copsin from Coprinopsis cinerea, Terpene of Erythrolobus australicus, and thionin from Arabidopsis thaliana were studied using bioinformatics analysis. Results: The results showed that these peptides (peptides studied in eukaryotics and prokaryotics) had cytoplasmic targeting and the studied peptides were not protected in different organisms. There was a variation in the number of α helixes and β sheets among the studied peptides. The results of the phylogenetic tree by Mega5 showed that besides Apis mellifera, four other species were located in the same cluster. The domains were different in the five studied species, but all domains had antibacterial properties. These peptides showed a wide range of physicochemical properties. The substitution template, substitution model, and D-Tajima sequence of the studied peptides showed that Apis mellifera was isolated from other species during evolution. Three-dimensional (3-D) modeling of peptides by the homology modeling method and Swiss Model database showed that the three-dimensional structure of terpene and thionin had high quality. Using peptidecutter and allermatch websites, it was found that nisin A, melitin, copsine, terpene, and thionin were not allergenic. To determine the minimum lethal concentration and minimum inhibitory concentration, the disk diffusion method was used. The highest inhibition of nisin of Lactococcus Lactis was obtained in Staphylococcus aureus and Escherichia coli by disk diffusion. Blank discs were 19, 23 mm, 5, and 1 mm, respectively. Discussion and conclusion: The results showed that nisin can be used as a natural preservative to delay food spoilage against gram-positive bacteria.

Keywords

• bioinformatic analysis
• antibacterial peptides
• eukaryote and prokaryote
• allergen
• inhibitory effects