title: YojI of Escherichia coli functions as a microcin J25 efflux pump.
abstract: In the present study, we showed that yojI, an Escherichia coli open reading frame with an unknown function, mediates resistance to the peptide antibiotic microcin J25 when it is expressed from a multicopy vector. Disruption of the single chromosomal copy of yojI increased sensitivity of cells to microcin J25. The YojI protein was previously assumed to be an ATP-binding-cassette-type exporter on the basis of sequence similarities. We demonstrate that YojI is capable of pumping out microcin molecules. Thus, one obvious explanation for the protective effect against microcin J25 is that YojI action keeps the intracellular concentration of the peptide below a toxic level. The outer membrane protein TolC in addition to YojI is required for export of microcin J25 out of the cell. Microcin J25 is thus the first known substrate for YojI.
authors.affiliation: Departamento de Bioquímica de la Nutrición, Instituto Superior de Investigaciones Biológicas (Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad Nacional de Tucumán), San Miguel de Tucumán, Argentina.
authors.forename: Mónica A
authors.initials: MA
authors.lastname: Delgado
authors.forename: Paula A
authors.initials: PA
authors.lastname: Vincent
authors.forename: Ricardo N
authors.initials: RN
authors.lastname: Farías
authors.forename: Raúl A
authors.initials: RA
authors.lastname: Salomón
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics* / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001430:Bacteriocins / Q000378:metabolism*; D002876:Chromosomes, Bacterial; D003001:Cloning, Molecular; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D016366:Open Reading Frames / Q000235:genetics; D010455:Peptides
chemical_list: D018528:ATP-Binding Cassette Transporters; D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D001430:Bacteriocins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D010455:Peptides; C073126:tolC protein, E coli; C020411:microcin