FIG. 5.
OhrR Y19A mutant is insensitive to CHP-mediated oxidation in vivo. (A) Induction of a PohrA-cat-lacZ reporter fusion was monitored in cells containing WT or Y19A OhrR after treatment with 0, 100, 200, 400, or 800 μM CHP for 15 min. (B) Analysis of the in vivo oxidation state of C15 in the Y19A mutant protein. Cells expressing the Y19A-FLAG OhrR protein were treated with 100 μM CHP for 1 min, and then IA was added to modify all reduced thiols. OhrR was recovered by immunoprecipitation, and the tryptic peptides were analyzed by MALDI-TOF MS. The resulting C15-containing peaks are indicated as described in the legend to in Fig. 3.