title: DNA supercoiling and aerobic regulation of transcription from the Klebsiella pneumoniae nifLA promoter.
abstract: Expression from the K. pneumoniae nifLA promoter is oxygen sensitive and is also inhibited by the DNA gyrase inhibitor coumermycin A1 under anaerobic growth conditions. The activity of this promoter was found to be highly sensitive to changes in DNA topology in vitro. Transcription was completely dependent on negative supercoiling at physiological salt concentrations although transcription from linear or fully relaxed closed circular templates was detectable at KCl concentrations lower than 50 mM. These observations suggest that aerobic regulation of nif transcription may be mediated through the level of DNA supercoiling.
authors.affiliation: AFRC Institute of Plant Science Research, University of Sussex, Brighton, UK.
authors.forename: R A
authors.initials: RA
authors.lastname: Dixon
authors.forename: N C
authors.initials: NC
authors.lastname: Henderson
authors.forename: S
authors.initials: S
authors.lastname: Austin
mesh_terms: D000332:Aerobiosis; D004278:DNA, Superhelical / Q000235:genetics*; D005786:Gene Expression Regulation; D005798:Genes, Bacterial; D007711:Klebsiella pneumoniae / Q000235:genetics*; D009586:Nitrogen Fixation / Q000235:genetics*; D010957:Plasmids; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic
chemical_list: D004278:DNA, Superhelical