FIG. 3.

Transcriptional activity of SoxR mutant proteins analyzed by β-galactosidase assays. Strain EH46 (soxS promoter-lacZ) cells expressing the various mutated SoxR proteins were either treated (black columns) or not (open columns) with 100 μM PQ for 1 h before the assay for β-galactosidase activity. β-Galactosidase activities are reported as percentages of the activity obtained with wild-type (WT) SoxR treated with 100 μM PQ (6,500 Miller units = 100%). The results shown represent the means and standard errors (bars; some not visible on this scale) of three independent experiments.