FIG 2.

Inhibition of ExsA-DNA binding by N-hydroxybenzimidazoles. ExsA (100 nM) (A and B) or ExsA_CTD (100 nM) (D) was incubated with DMSO (2.5%) or the indicated N-hydroxybenzimidazole (125 μM) for 5 min prior to addition of an equimolar mixture of radiolabeled P_exsC and nonspecific algD DNA probes (0.05 nM each). Binding reactions were allowed to proceed for 15 min at 25°C and then analyzed by native polyacrylamide gel electrophoresis and phosphorimaging. The positions of shift products 1 and 2 are indicated. (C) Representative titration experiment used to determine the half-maximal inhibitory concentration (IC₅₀) of each N-hydroxybenzimidazole required to inhibit ExsA-DNA binding. The percent shifted probe (y axis) was plotted as a function of N-hydroxybenzimidazole concentration (x axis).