Production of an Antimicrobial Peptide AN5-1 in Escherichia coli and its Dual Mechanisms Against Bacteria

AN5-1 (YSKSLPLSVLNP) is an antimicrobial peptide isolated from the fermentation broth of Paenibacillus alvei strain AN5 (J Ind Microb Biotechnol 2013; 40: 571-9). In this study, we report the application of ubiquitin fusion technology to the expression and purification of AN5-1. Minimum inhibitory concentration (MIC) and measurement of hemolytic activity (MHC) were measured to confirm the biological activities of the expressed AN5-1. Bacterial cell membrane permeabilization was investigated to show the interaction between the AN5-1 and the bacterial cytoplasmic membrane. Furthermore, intracellular activities of the AN5-1 were determined by genomic DNA interaction assays. The results revealed AN5-1 damaging bacterial membranes and binding to bacterial genomic DNA to inhibit cellular functions, suggesting that it has multiple intracellular targets in bacteria. The application of ubiquitin fusion technology may be an excellent approach for industrial production to the expression and purification of antimicrobial peptide. Furthermore, AN5-1 was demonstrated as an antimicrobial peptide with great potentials, as bacterial resistance to AN5-1 would be not expected, due to the dual mechanisms of AN5-1 against bacteria.