CHALON Miriam Carolina
congresos y reuniones científicas
ROS production induced by Microcin J25 is mediated by Cytochrome bd
GALVAN, AE; CHALON M.C.; SCHURIG-BRICCIO L; MINAHK, C.J; GENNIS R; BELLOMIO, A
Mar del Plata
Congreso; Reunión Anual de la Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular; 2015
Microcin J25 (MccJ25) is a plasmid-encoded lasso peptide secreted by Escherichia coli. It displays antibiotic activity against a range of food-borne Gram-negative pathogens including Escherichia coli, Salmonella and Shigella. MccJ25 is a potential candidate for a number of applications including food preservation and treatment of food-borne diseases because it is resistant to proteolytic degradation and extreme temperatures. MccJ25 has two cellular targets, the RNA polymerase and the membrane respiratory chain inhibiting the cell oxygen consumption and increasing the superoxide production. E. coli has two terminal oxidoreductases, the cytochrome bd and cytochrome bo3 in its respiratory system. The E. coli C43 strain (wild type) was sensitive to the peptide whereas the ∆bdI ∆bdII double mutant became resistant. In this work we evaluated the sensitivity of these strains in presence of ascorbic acid. We observed that the peptide activity was lower when the antioxidant was present. Previously we had demonstrated that MccJ25 inhibits the cytochrome bdI oxidoreductase activity in vitro. Therefore we decided to investigate in vitro reactive oxygen species (ROS) production with membranes of these mutant strains. The cytochrome bd double mutant membrane produced the lowest ROS level indicating the role of this oxidoreductase in the MccJ25 mechanism of action.