The molybdate-responsive Escherichia coli ModE transcriptional regulator coordinates periplasmic nitrate reductase (napFDAGHBC) operon expression with nitrate and molybdate availability.

ABSTRACT: Expression of the Escherichia coli napFDAGHBC operon (also known as aeg46.5), which encodes the periplasmic molybdoenzyme for nitrate reduction, is increased in response to anaerobiosis and further stimulated by the addition of nitrate or to a lesser extent by nitrite to the cell culture medium. These changes are mediated by the transcription factors Fnr and NarP, respectively. Utilizing a napF-lacZ operon fusion, we demonstrate that napF gene expression is impaired in strain defective for the molybdate-responsive ModE transcription factor. This control abrogates nitrate- or nitrite-dependent induction during anaerobiosis. Gel shift and DNase I footprinting analyses establish that ModE binds to the napF promoter with an apparent K(d) of about 35 nM at a position centered at -133.5 relative

SUBMITTER: McNicholas PM 

PROVIDER: S-EPMC135098 | biostudies-literature | 2002 Jun

REPOSITORIES: biostudies-literature