ROS production induced by microcin J25 is mediated by cytochrome bd

GALVAN, E; CHALON, M; SCHURIG-BRICCIO, L; MINAHK, C; GENNIS, R; BELLOMIO, A

Mar del Plata

Congreso; LI Reunión Anual SAIB; 2015

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Microcin J25 (MccJ25) is a plasmid-encoded lasso peptide secreted by Escherichia coli that displays antibiotic activity against a range of food-borne Gram-negative pathogens including Escherichia coli, Salmonella and Shigella. The peptide is a potential candidate for a number of applications including food preservation because its resistance to proteolytic degradation and extreme temperatures. The membrane Respiratory chain is one of the targets of MccJ25. In fact, this peptide inhibits the oxygen consumption and increases the superoxide production. As a matter of fact, wild type E. coli C43 strain was sensitive to the peptide whereas the ΔbdI ΔbdII double mutant became resistant.Since we had previously demonstrated that MccJ25 inhibited the cytochrome bdI oxidoreductase activity, we decided to investigate in vitro ROS production with membranes of these mutant strains. The cytochrome bd double mutant membrane produced the lowest ROS level, indicating a possible role of this oxidoreductase in the MccJ25 mechanism of action. Moreover, we evaluated the sensitivity of different E. coli strains in the presence of the antioxidant ascorbic acid, confirming that the peptide activity was lower when this compound was present.