A promoter region binding protein and DNA gyrase regulate anaerobic transcription of nifLA in Enterobacter cloacae.

Our work provides evidence that a sequence characteristic of FNR binding sites, when interacted with by a trans-acting factor, activates anaerobic transcription of the nifLA operon in Enterobacter cloacae. DNA gyrase activity has been found to be important for the anaerobic transcription of the nifLA promoter. Our results suggest that anaerobic regulation of the nifLA operon is mediated through the control of the promoter region-binding trans-acting factor at the transcriptional level, while DNA supercoiling functions in providing a topological requirement for the activation of transcription.