title: Bacterial DNA supercoiling and [ATP]/[ADP] ratio: changes associated with salt shock.
abstract: When Escherichia coli K-12 was shifted from a medium lacking salt to one containing 0.5 M NaCl, both the [ATP]/[ADP] ratio and negative supercoiling of plasmid DNA increased within a few minutes. After about 10 min both declined, eventually reaching a level slightly above that observed with cells growing exponentially in the absence of salt. Since in vitro the [ATP]/[ADP] ratio influences the level of supercoiling generated by gyrase (H. Westerhoff, M. O'Dea, A. Maxwell, and M. Gellert, Cell Biophys. 12:157-181, 1988), the physiological response of supercoiling to salt shock is most easily explained by the sensitivity of gyrase to changes in the intracellular [ATP]/[ADP] ratio. This raises the possibility that the [ATP]/[ADP] ratio is an important factor in the control of supercoiling.
authors.affiliation: Public Health Research Institute, New York, New York 10016.
authors.forename: L S
authors.initials: LS
authors.lastname: Hsieh
authors.forename: J
authors.initials: J
authors.lastname: Rouviere-Yaniv
authors.forename: K
authors.initials: K
authors.lastname: Drlica
mesh_terms: D000244:Adenosine Diphosphate / Q000032:analysis*; D000255:Adenosine Triphosphate / Q000032:analysis*; D049933:Aminocoumarins; D003374:Coumarins / Q000494:pharmacology; D004250:DNA Topoisomerases, Type II / Q000378:metabolism; D004269:DNA, Bacterial / Q000737:chemistry* / Q000187:drug effects; D004278:DNA, Superhelical / Q000737:chemistry* / Q000187:drug effects; D004926:Escherichia coli / Q000378:metabolism; D009154:Mutation; D010957:Plasmids; D012965:Sodium Chloride / Q000737:chemistry*
chemical_list: D049933:Aminocoumarins; D003374:Coumarins; D004269:DNA, Bacterial; D004278:DNA, Superhelical; D012965:Sodium Chloride; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D004250:DNA Topoisomerases, Type II; C004628:coumermycin