Study of the lasso peptide microcin J25 effect on the E. coli terminal oxidases

GALVAN, E; CHALON, M; MINAHK, C; BELLOMIO, A

San Miguel de Tucumán

Congreso; IIILAFeBS - XLV Reunión Anual Sociedad Argentina de Biofísica; 2016

Sociedad Argentina de Biofísica

The antimicrobial lasso peptide microcin J25 (MccJ25) displays a bacteriostatic activity by inhibiting RNA polymerase. This peptide is secreted by Escherichia coli and it can also target the enzymes of the respiratory chain on the bacterial membrane. E. coli has two type terminal oxidoreductases, the cytochrome bd (bdI and bdII) and cytochrome bo3. Previously, it was demonstrated that the MccJ25 inhibits the cell respiration and increases the superoxide production. In this work, the effect of this peptide on E. coli C43 cytochrome deficient strains was studied. We evaluated the NADH dehydrogenase activity and the oxygen consumption rate. MccJ25-GA1 and Y9F2 are two modified peptides obtained in our laboratory. The ability of these peptides to inhibit the ubiquinol oxidase activity and to produce a superoxide overproduction in the purified cytochromes was also analyzed. Our results indicate that both, cytochrome bdI and bo3, are necessary for MccJ25 inhibitory effect. Because of its extreme resistance to proteolytic degradation and high temperatures, MccJ25 is a potential candidate for a number of applications including food preservation and treatment of food-borne diseases.