Construction and characterization of mutations at codon 751 of the Escherichia coli gyrB gene that confer resistance to the antimicrobial peptide microcin B17 and alter the activity of DNA gyrase.
Microcin B17 is a peptide antibiotic that inhibits DNA replication in Escherichia coli by targeting DNA gyrase. Previously, two independently isolated microcin B17-resistant mutants were shown to harbor the same gyrB point mutation that results in the replacement of tryptophan 751 by arginine in the GyrB polypeptide. We used site-directed mutagenesis to construct mutants in which tryptophan 751 was deleted or replaced by other amino acids. These mutants exhibit altered DNA gyrase activity and different levels of resistance to microcin B17.
Unidad de Genética Molecular, Hospital Ramón y Cajal, 28034-Madrid, Spain.
F J
FJ
del Castillo
I
I
del Castillo
F
F
Moreno
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001430:Bacteriocins / Q000494:pharmacology*; D003062:Codon; D027081:DNA Gyrase; D004250:DNA Topoisomerases, Type II / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D010455:Peptides; D010641:Phenotype; D016415:Sequence Alignment
D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D003062:Codon; D010455:Peptides; C020411:microcin; D027081:DNA Gyrase; D004250:DNA Topoisomerases, Type II