FIGURE 10.

Effects of mutations of three cysteines on the IscR activity. Total RNAs and proteins were isolated from the strains grown aerobically to an A₆₀₀ of 0.3. A, the prx3 mRNA levels in the total RNA were determined by qRT-PCR analyses, and the prx3 mRNA level in the wild type was set to 1. B, protein samples were resolved by SDS-PAGE, and IscR or IscR_3CA was detected by Western blotting using a rabbit anti-IscR antiserum. The positions of protein size markers (in kDa; Bio-Rad) are shown on the right of the gel. In the graph, the IscR protein levels were calculated based on the band intensities, and the IscR protein level in the wild type was set to 1. Error bars, S.E. **, p < 0.005 relative to WT. iscR, iscR mutant; iscR_3CA, a strain expressing apo-locked IscR_3CA.