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

GALVÁN, ADRIANA EMILCE; BELLOMIO, AUGUSTO; MINAHK, CARLOS JAVIER; CHALÓN, MIRIAM CAROLINA

San Miguel de Tucumán

Congreso; III Latin American Federation of Biophysical Societies (LAFeBS) - IX IberoAmerican Congress of Biophysics - XLV Reunion Anual SAB 2016; 2016

The antimicrobial lasso peptide microcin J25 (MccJ25) displays a bacteriostaticactivity by inhibiting RNA polymerase. This peptide is secretedby Escherichia coli and it can also target the enzymes of the respiratorychain on the bacterial membrane. E. coli has two type terminaloxidoreductases, the cytochrome bd (bdI and bdII) and cytochrome bo3.Previously, it was demonstrated that the MccJ25 inhibits the cell respirationand increases the superoxide production. In this work, the effectof this peptide on E. coli C43 cytochrome deficient strains was studied.We evaluated the NADH dehydrogenase activity and the oxygenconsumption rate. MccJ25-GA1 and Y9F2 are two modified peptidesobtained in our laboratory. The ability of these peptides to inhibit theubiquinol oxidase activity and to produce a superoxide overproductionin the purified cytochromes was also analyzed. Our results indicate thatboth, 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 applicationsincluding food preservation and treatment of food-borne diseases.Acknowledgements: We thanks to phD Gennis, R. and Schurig-BriccioL. from Deparment of Biochemistry, University of Illinois for give usthe E. coli C43 strains and cytochromes overexpressing plasmids.