FIG. 4.

EMSAs show direct interaction of recombinant PypBΔc and PypC with the hreP promoter region. Increasing amounts of recombinant PypBΔc (A) or PypC (B) were incubated with a DIG-labeled DNA fragment encompassing 250 nt 5′ of the hreP start codon, resulting in a mobility shift of the DNA fragment. Shifting of the probe can be inhibited by specific, but not by nonspecific, competitor DNA. Incubation of the probe with PypC results in additional shifted bands that cannot be blocked by specific or nonspecific competitor DNA, indicating nonspecific interaction with PypC.