title: Requirements for transcriptional activation in vitro of the nitrogen-regulated glnA and nifLA promoters from Klebsiella pneumoniae: dependence on activator concentration.
abstract: Three proteins involved in nitrogen regulation in Klebsiella pneumoniae, NTRA, NTRB and NTRC, have been purified. In a defined in vitro system all three NTR proteins are required for initiation of transcription at the ntr activatable glnA and nifLA promoters. However, in crude S-30 extracts, transcription from the glnA promoter, but not the nifLA promoter, can be activated in the absence of NTRB. A higher concentration of NTRC is required for activation of nifLA transcription than for glnA transcription. Sequences located between -227 and -158 with respect to the nifL transcription start site are required for efficient activation of the nifLA promoter in vitro.
authors.affiliation: AFRC Unit of Nitrogen Fixation, University of Sussex, Brighton, UK.
authors.forename: S
authors.initials: S
authors.lastname: Austin
authors.forename: N
authors.initials: N
authors.lastname: Henderson
authors.forename: R
authors.initials: R
authors.lastname: Dixon
mesh_terms: D001483:Base Sequence; D005786:Gene Expression Regulation; D005798:Genes, Bacterial; D007711:Klebsiella pneumoniae / Q000235:genetics*; D009586:Nitrogen Fixation / Q000235:genetics*; D010957:Plasmids; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D013698:Templates, Genetic; D014158:Transcription, Genetic