Panel A: Sequence logo representing the consensus sequence of pha promoter regions identified by the program MEME motif discovery tool. In the y axis the information is represented in bits indicating the nucleotide frequency in the sequence at that position. The putative consensus sequence probably recognized by PhbF is indicated. Panel B: DNase I-protection footprinting assay was carried out as described in Material and Methods. The non-coding strand of the phbF promoter was used as a probe. The assays were in the absence (lane 1) or presence 155 (lane 2) or 312 nM (lane 3) of the purified His-PhbF tetramer. Lane P indicates the undigested promoter region. The DNA sequencing reaction is indicated in lanes A, C, G, and T. The region showing protection from DNaseI digestion is indicated by **. The probable σ70 promoter is indicated by *. Numbers indicate base position corresponding to the translation start codon.