title: Changed properties of the A subunit in DNA gyrase with a B subunit mutation.
abstract: To investigate the interaction of subunits A and B of DNA gyrase during DNA supercoiling, a Cour mutant of Escherichia coli was obtained and the effect of nalidixic acid on the supercoiling of DNA by wild-type and mutant enzymes was assayed. The enzyme of the Cour strain proved to be more sensitive to nalidixic acid than the wild-type DNA gyrase. Hence the mutation affecting the B subunit can also change the properties of the A subunit, which fact suggests that the two subunits of DNA gyrase are in contact during DNA supercoiling.
mesh_terms: D004250:DNA Topoisomerases, Type II / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D004278:DNA, Superhelical / Q000235:genetics*; D004792:Enzyme Precursors / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D009154:Mutation; D010641:Phenotype
chemical_list: D004269:DNA, Bacterial; D004278:DNA, Superhelical; D004792:Enzyme Precursors; D004250:DNA Topoisomerases, Type II