Oxygen-regulated in vitro transcription of Rhizobium meliloti nifA and fixK genes

Two proteins, FixL and FixJ, belonging to the two-component family of regulatory proteins, are essential for oxygen-regulated in vitro transcription of two vital regulatory genes nifA and fixK. FixJ is a transcriptional activator which functions in combination with the RNA polymerase sigma 70 holoenzyme. FixJ transcriptional activity is augmented by the addition of FixL122 to the transcription assay.