FIG. 3.

Binding of the purified PrfA proteins to the plcA-hly promoter fragment. Various amounts of PrfA preparation were used (from left to right: PrfA* [Gly145Ser], 0.5, 1.5, 3, 6, and 18 ng; PrfA, 120, 240, and 480 ng). Lanes a and b: low-mobility CI-specific protein-DNA complex formation by purified PrfA* and PrfA proteins (50 ng each), respectively, in the presence of a PrfA-free L. monocytogenes cell extract (30 μg) from EGD ΔprfA. CIII, high-mobility specific PrfA-DNA complexes. (See text and references 3 and 9 for details.)