Figure 5. Ionic strength dependence on MCR1:DNA complex formation.
(A) Electrophoretic mobility shift assays of radiolabeled WT 12-RSS (left panel) and MHMN (right panel) titrated with MCR1 in binding buffer containing 0.4 M NaCl. The MCR1 concentration in lanes 2–8 in each panel was at 0.1, 0.2, 0.4, 0.6, 0.8, 1.2, and 1.6 μM, respectively. The MCR1:DNA complexes are labeled as in Figure 1A. (B) Plots of −log Kd versus NaCl concentration for the interaction of MCR1 with WT 12-RSS (gray circles) and MHMN (open squares). The error bars are from n=3 experiments. The linear least squares correlations are shown for the MCR1:MHMN association from 0.1–0.5 M NaCl (black line), and from 0.2–0.5 M NaCl for the MCR1:WT12-RSS association (gray line).