FIG 4.

Cu(II) and Zn(II) trigger BosR dissociation from its DNA target. (A) When added to reactions after the formation of a BosR₂-DNA complex, Cu(II) and Zn(II) triggered BosR₂ dissociation from its DNA target, as evident in the dose-dependent reduction in FA. Four independent replicates were tested for each condition. (B) When EDTA was added to two of the replicates to a final concentration of 1 mM, it abolished the inhibitory effect of Zn(II) but not that of Cu(II). (C) When TCEP was added to the other two replicates to a final concentration of 1 mM, it abolished the inhibitory effect of Cu(II) but not that of Zn(II). The curves were fitted for dose response of inhibition with variable slope using GraphPad Prism 6. R² was ≥0.99 for all curves except those of ZnSO₄ plus EDTA and CuSO₄ plus TCEP, where the inhibitory effect of metal ions was significantly diminished.