A model for the domain structure of σ54‐dependent transcriptional activators, based on
sequence data, has been tested by examining the function of truncated and chimaeric …

Activation of transcription at the Klebsiella pneumoniae nifLA promoter requires the
phosphorylated form of the positive control protein NTRC, together with RNA polymerase …

Four substitutions at serine residue 160 which increase the activity of the σ54‐dependent
activator protein NTRC in the absence of NTRB have been analysed in detail. Mutagenesis …

The interaction of the Klebsiella pneumoniae NifA protein, a σ 54-dependent activator, with
the nifE and nifU promoters was analysed. At these promoters NifA established contacts in …

The Klebsiella pneumoniae nitrogen regulatory protein NTRC is a response regulator which
activates transcription in response to nitrogen limitation, and is a member of the family of σN …

The regulatory region spanning the divergently transcribed nif F and nifLA promoters
contains a NIFA‐specific upstream activator sequence (UAS) located around+ 59, and two …

The positive control protein NifA of Klebsiella pneumoniae activates transcription by RNA
polymerase containing σ 54 by catalysing open promoter complex formation. We show that …

We present the nucleotide sequence of K. pneumoniae nifL, which negatively regulates nif
transcription in response to oxygen and fixed nitrogen. It shows partial sequence homology …

The alterNatlve sigma factor σ54 is required for transcription of nitrogen fixation genes in
Klebsiella pneutnoniae and other diazotrophs. The nif genes, and other Eσ54‐dependent …

We have constructed mutations in what we predict to be the DNA-recognition helix of
Klebsiella pneumoniae NtrC, which regulates transcription from promoters under global …