Promoter 7 of the Escherichia coli pfl operon is a major determinant in the anaerobic regulation of expression by ArcA.

The anaerobically inducible pfl operon of Escherichia coli has a regulatory sequence comprising 494 bp, which includes two anaerobically regulated promoters, termed P6 and P7. In this study, we show that in its normal context the activity of P7 is constrained and that one important function of the promoter is to mediate controlled ArcA-dependent regulation of the operon.