FIG. 5.

Promoter binding activity of IolR. The interaction of IolR with the regulatory region of nine genes of GEI 4417/4436 is shown. One hundred nanograms of DNA was used in each experiment. The promoter fragments were incubated without or with increasing amounts (7 ng, 14 ng, 28 ng, and 49 ng [221 fM, 442 fM, 884 fM, and 1547 fM, respectively]) of the purified IolR protein. No bandshift was observed when a maximum of 210 to 280 ng IolR, corresponding to a maximal 17-fold molar excess, was incubated with promoter DNAs of iolE, iolG2, iolI, and iolH (data not shown). Protein-DNA complexes were separated on a 9.5% native polyacrylamide gel. A 200-bp sequence of the argS promoter served as a negative control.