FIG. 4.

CtsR binds specifically to the clpC, clpP, and clpE promoter regions. In gel mobility shift experiments (A), radiolabeled DNA fragments (10,000 cpm) corresponding to the clpC, clpP, and clpE promoter regions were incubated with increasing amounts of purified CtsR as follows: for clpC and clpP, lanes 1 to 6, 0, 10, 20, 40, 60, and 80 ng of CtsR, respectively; for clpE, lanes 1 to 4, 0, 20, 40, and 80 ng of CtsR, respectively. In DNase I footprinting analyses of CtsR binding (B), 50,000 cpm of each radiolabeled DNA fragment corresponding to the clpC, clpP, or clpE promoter region was incubated with increasing amounts of purified CtsR as follows: lanes 1 to 5, 0, 100, 200, 400, and 800 ng of CtsR, respectively; lane 6, G+A Maxam and Gilbert reaction of the corresponding DNA fragments. Regions protected by CtsR are shown by brackets.