title: Heat shock-induced DNA relaxation in vitro by DNA gyrase of Escherichia coli in the presence of ATP.
abstract: Genetic studies revealed that DNA gyrase seems to catalyze immediate and transient DNA relaxation after Escherichia coli cells are exposed to heat shock (Ogata, Y., Mizushima, T., Kataoka, K., Miki, T., and Sekimizu, K. (1994) Mol. Gen. Genet. 244, 451-455). We have now obtained biochemical evidence to support this hypothesis. DNA gyrase catalyzed an increase in the linking number of DNA and relaxation of negatively supercoiled DNA, under physiological concentrations of ATP. Analyses by gel filtration chromatography of each subunit revealed that DNA relaxation activity co-migrated with each subunit. The linking number of DNA increased as the temperature increased. Further, the reaction was inhibited by nalidixic acid or by oxolinic acid. Based on these results, we propose that DNA gyrase participates in a concerted reaction with DNA topoisomerases in the immediate relaxation of DNA in cells exposed to heat shock.
authors.affiliation: Department of Microbiology, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-82, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kataoka
authors.forename: T
authors.initials: T
authors.lastname: Mizushima
authors.forename: Y
authors.initials: Y
authors.lastname: Ogata
authors.forename: T
authors.initials: T
authors.lastname: Miki
authors.forename: K
authors.initials: K
authors.lastname: Sekimizu
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D002384:Catalysis; D004250:DNA Topoisomerases, Type II / Q000378:metabolism*; D004274:DNA, Recombinant / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D006358:Hot Temperature; D009154:Mutation; D009690:Nucleic Acid Conformation; D017384:Sequence Deletion
chemical_list: D004274:DNA, Recombinant; D000255:Adenosine Triphosphate; D004250:DNA Topoisomerases, Type II