FIG. 6.

CRP activation of ykgR. (A) Sequence of the ykgR promoter and coding region. The +1 site of transcription (position 312510 of the E. coli K-12 genome) is denoted with an arrow. A potential σ⁷⁰ −10 sequence is indicated in bold, and the predicted CRP binding site is boxed. (B) Primer extension analysis of ykgR-SPA mRNA (top) and Western blot analysis of YkgR-SPA protein (bottom) levels in MG1655 and Δcrp cells grown in minimal glucose (glu) and minimal glycerol (gly) medium supplemented with 0.2% Casamino Acids and 0.0005% vitamin B₁. M63 glucose and M63 glycerol cultures (inoculated from overnight cultures grown in the respective medium) were grown at 37°C to an OD₆₀₀ of 0.3 to 0.4. Primer extension assays were conducted using 5 μg total RNA of each sample and an end-labeled oligonucleotide complementary to the ykgR ORF. Western blot analysis was performed as stated for Fig. 2. The asterisk denotes a band corresponding to the full-length SPA-tagged YkgR protein.