Label‐free Proteomics study on Shewanella putrefaciens regulated by ε‐Poly‐lysine treatment

AIMS The purpose of this study was to investigate the regulatory mechanism of e-PL on Shewanella putrefaciens. METHODS AND RESULTS Proteomics analysis of inhibitory effect of e-PL against S. putrefaciens were performed by label-free quantitative assay based on high-resolution mass spectrometry (MS). Quantification of 2206 proteins was obtained with high confidence, and a total of 36 differentially expressed proteins (DEPs), with 10 and 26 proteins showing up- and down-regulation, respectively, were identified. Upon Go functional enrichment, 11, 5, and 8 specific Go terms in biological processes, molecular functions and cellular components were identified, respectively. Six KEGG pathways, including "ribosome", were significantly enriched. Among the ribosome pathway, there were 7 DEPs and all of them were distributed on large and small subunits of ribosome. CONCLUSIONS The significant down-regulation of proteins, large subunits of ribosomal proteins RP-L18, L30 and L27, small subunits ribosomal proteins S16 and S20, and RNA polymerase β' subunit protein rpoC were the critical action sites of e-PL to inhibit S. putrefaciens growth. SIGNIFICANCE AND IMPACT OF THE STUDY S. putrefaciens is one of the representative fish-spoilage bacteria regardless of fish type, and poses significant problems for the fish brewery. A better understanding of the antibacterial mechanism of e-PL on S. putrefaciens could make important contributions to development of biological control strategies of these economically important pathogens.