Analysis of antibacterial mechanism of antibacterial peptide F1 by iTRAQ quantitative proteomics

Antimicrobial peptides have attracted more and more attention in agriculture and food industry because of their potential to control pathogens However, in order to promote the development of new antimicrobial agents based on active peptides, it is necessary to have a deep understanding of the molecular mechanism of these peptides In this study, iTRAQ quantitative proteomic analysis technology was used to analyze and identify the growth rate of E.coli treated with antimicrobial peptide F1 and the blank control in different periods of time, as well as the protein produced by them By comparing the protein expression level differences between the experimental group and the control group, we hope to understand the antibacterial mechanism of antimicrobial peptide F1 In the process of culture, the outline of cell membrane of E.coli treated with antibacterial peptide F1 was gradually lost, and the cell size was gradually reduced, which indicated that the treatment of antibacterial peptide F1 resulted in the damage of cell membrane, the leakage of cytoplasm and the contraction of bacterial cell After 2 hours of treatment with antibacterial peptide F1, the cells showed severe deformation and partial cleavage, with unrecognized cell morphology A total of 280 proteins were identified in E.coli treated with antibacterial peptide F1, 31 of which were altered in expression, including 10 down regulated proteins and 21 up regulated proteins These 31 proteins have different molecular functions and participate in different molecular pathways Specifically, the pathways that significantly change in E.coli in response to antimicrobial peptide F1 treatment include: tricarboxylic acid cycle, oxidative phosphorylation, glycerol phospholipid metabolism and cell cycle bacterial pathway, which are also related to cell growth inhibition, induced morphological changes and cell death Fig transmission electron microscope analysis of Escherichia coli in different periods of culture with antibacterial peptide F1 When F1 was used to treat E.coli, there was a complete change of protein expression Its characteristic changes included the downregulation of major catalytic enzymes involved in energy metabolism and the upregulation of proteins with peptidase activity, catalytic activity and hydrolase activity The inhibition of tricarboxylic acid cycle pathway and oxidative phosphorylation pathway may be related to the observed decrease of cell growth and cell death The promotion of glycerol phospholipid metabolism pathway and cell cycle Enterobacteriaceae pathway potentially increases the permeability of cell membrane, leading to cell autolysis and cell death In general, the results of this study provide new insights into the antibacterial molecular mechanism of antibacterial peptide F1