FIG 3 .

Zinc increases binding of CopY to the cop promoter. (A) Fluorescence polarization assay of CopY binding to 10 nM pSP_0727 with FAM and with and without 10 µM zinc. Curve fit to one-site binding (hyperbola). Data are representative of three individual experiments. (B) Fluorescence polarization assay of CopY binding to 10 nM pSP_0727 with FAM in the presence of Zn²⁺ starting with the DNA and protein concentrations required for 40% binding in panel A (2 µM CopY and 10 nM DNA). Curve fit to sigmoidal, four-parameter logistic, where x is the log concentration. Data are representative of four individual experiments.