title: DNA gyrase can cleave short DNA fragments in the presence of quinolone drugs.
abstract: We have analysed the DNA cleavage reaction of DNA gyrase using oligonucleotides annealed to a single-stranded M13 derivative containing a preferred gyrase cleavage site. We find that gyrase can cleave duplexes down to approximately 20 bp in size in the presence of the quinolone drugs ciprofloxacin and oxolinic acid. Ciprofloxacin shows a variation in its site specificity with an apparent preference for G bases adjacent to the cleavage sites, whereas oxolinic acid stimulates cleavage predominantly at the previously determined site. With either drug, cleavage will not occur within 6 bases from the end of a DNA duplex or a nick. We suggest that cleavage site specificity with short DNA duplexes is determined by drug-DNA interactions whereas with longer fragments the positioning effect of the DNA wrap around gyrase prescribes the site of cleavage.
authors.affiliation: Department of Biochemistry, University of Leicester, Leicester LE1 7RH, UK.
authors.forename: M E
authors.initials: ME
authors.lastname: Cove
authors.forename: A P
authors.initials: AP
authors.lastname: Tingey
authors.forename: A
authors.initials: A
authors.lastname: Maxwell
mesh_terms: D017104:Bacteriophage M13; D001483:Base Sequence; D001665:Binding Sites; D002939:Ciprofloxacin / Q000494:pharmacology*; D004247:DNA / Q000187:drug effects* / Q000378:metabolism; D004250:DNA Topoisomerases, Type II / Q000378:metabolism*; D008969:Molecular Sequence Data; D010093:Oxolinic Acid / Q000494:pharmacology*; D013379:Substrate Specificity
chemical_list: D002939:Ciprofloxacin; D004247:DNA; D004250:DNA Topoisomerases, Type II; D010093:Oxolinic Acid