Figure 8.

Cysteine variants bind DNA with reduced affinity. A, OstR-C3A binding emrB promoter DNA. DNA (0.2 nm) was titrated with increasing concentration of OstR-C3A (1–200 nm; lanes 2–13). Lane 1, free DNA only. Free DNA and protein–DNA complex are shown as FD and C1–C3, respectively, at the right. C and E, EMSA showing binding of OstR-C4 and OstR-C169A to promoter DNA, respectively. B, D, F, normalized complex fraction for OstR-C3A, OstR-C4A, and OstR-C169A, respectively, plotted as a function of protein concentration. Error bars, S.D. of three replicates.