Essential roles of three enhancer sites in σ54-dependent transcription by the nitric oxide sensing regulatory protein NorR

摘要: The bacterial activator protein NorR binds to enhancer-like elements, upstream of the promoter site, and activates 54-dependent transcription genes that encode nitric oxide detoxifying enzymes (NorVW), in response NO stress. Unique norVW Escherichia coli is presence three enhancer sites associated with a binding site for 54-RNA polymerase. Here we show all are required NorR-dependent catalysis open complex formation by 54-RNAP holoenzyme (E54). We demonstrate this essentially due need enhancers maximal ATPase activity NorR, energy from which used remodel closed E54 allow melting DNA. also find site-specific DNA per se promotes oligomerisation but flanking needed further stabilise functional higher order oligomer at enhancers.