FIG. 1.

Organization of the nrf-acs intergenic region. The figure shows a schematic representation of the pnrf433, pnrf53, and pnrf53/Δ87 promoter fragments and the important elements involved in regulation of the nrf and acsP2 promoters. The upstream boundary for each promoter fragment is given, and the locations of transcription start sites for pnrf and acsP2 are indicated by arrows. FNR, CRP, and NarL/NarP binding sites are represented by inverted arrows, while IHF and Fis binding sites are depicted by boxes. The central base pair of each DNA binding site is indicated, and all numbering is in relation to the transcription start of the nrf promoter (+1).