FIG. 1.

(A) Sequence alignment of the rrn P1 promoters. Sequences were compiled from the E. coli K-12 MG1655 complete genome (GenBank accession no. U00096). The −35 and −10 hexamers are in boldface and boxed. FIS binding sites identified by DNase I footprints are in boldface and shaded. (B) Representative FIS footprint with DNase I (rrnE P1 FIS site I). The bracket indicates the extent of FIS protection. Positions within the FIS footprint that are either accessible to DNase I or display enhanced cleavage are indicated by capital letters in panel A and arrows in panel B. (C) Schematic alignment of the rrn P1 promoters showing the locations of FIS sites relative to the core promoter (−10 and −35 hexamers) and UP element regions.