FIG. 5.

Transcriptional regulation of cap gene expression by KdpE. (A) Relative transcript levels of the cap gene (represented by capN and capG) in the S. aureus NCTC8325 wild type (WT), the kdpDE mutant (SX8), the kdpDE mutant with a plasmid containing kdpDE (SX9), the kdpE mutant (SX10), the kdpE mutant with a plasmid containing kdpE (SX11), and the kdpE mutant with a plasmid encoding KdpE with a mutated Asp-phosphorylation site (SX12). (B) Binding of KdpE protein to the promoter of cap. The ability of KdpE to bind to the cap promoter was determined by gel-shift assay. Increasing amounts of KdpE were incubated with excess DIG-labeled probes. Lanes 1 to 6, KdpE concentrations of 0, 0.5, 1, 2, 4, and 4 μM, respectively; the amount of DIG-labeled probe in each case was 50 fmol (the concentration was 5 nM). In lane 6, besides the labeled probes, 500 fmol of unlabeled probes was incubated with the KdpE protein.