Raúl Armando Salomón

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A 4.8-kb plasmid region carrying the four genes mcjABCD necessary for production of and immunity to the cyclic peptide antibiotic microcin J25 (MccJ25) has been sequenced. mcjA encodes the primary structure of MccJ25 as a precursor endowed with an N-terminal extension of 37 amino acids. The products of mcjB and mcjC are thought to be involved in microcin(More)
Escherichia coli microcin J25 (MccJ25) is a 2107-Da peptide antibiotic whose uptake into E. coli is mediated by the outer-membrane receptor FhuA and the inner membrane proteins TonB, ExbB, ExbD, and SbmA. A survey of the sensitivity of several Salmonella enterica serovars showed that the antibiotic was highly active against some serovars, while S.(More)
OBJECTIVES Starting from the observation that Escherichia coli tolC mutations severely reduced the high-level resistance to tetracycline afforded by Tn10- and plasmid-encoded Tet(A) pumps, we studied the mechanism of this susceptibility. METHODS The MIC of tetracycline for MC4100 tolC::Tn10 and several tolC mutants carrying the Tn10 in other sites on the(More)
Microcin J25 is a 2,107-Da, plasmid-encoded, cyclopeptide antibiotic produced by Escherichia coli. We have isolated lacZ fusions to mcjA (encoding the 58-amino-acid microcin precursor) and mcjB and mcjC (which are required for microcin maturation), and the regulation of these fusions was used to identify factors that control the expression of these genes.(More)
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(More)
The Escherichia coli sbmA gene has been identified in screens for mutants resistant to the peptide antibiotics microcin B17 and microcin J25, the glycopeptide antibiotic bleomycin and eukariotic peptide antibiotics. Homologs of sbmA have been found in a wide variety of bacteria; however, the natural function of SbmA remains unknown. We demonstrate here that(More)
The role of lipid transfer proteins during plasma membrane biogenesis was explored. Developing amphibia embryos were used because during their growth an active plasma membrane biosynthesis occurs together with negligible mitochondrial and endoplasmic reticulum proliferation. Sonicated vesicles, containing 14C-labeled phospholipids and 3H-labeled triolein,(More)
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