FIGURE 6. Effect of procainamide on the binding of DNMT1 to hairpin oligonucleotides.
A, DNMT1 was incubated with 10 nm unmethylated hairpin (closed circles), hemimethylated hairpin (open circles), or fully methylated hairpin (closed triangles) at 4 ºC for 1 h. Fluorescence anisotropy values were obtained, converted to fraction bound, and plotted against the concentration of DNMT1 to calculate dissociation constants. B, DNMT1 at saturating levels (400 nm) was incubated with 10 nm hemimethylated hairpin in the presence of varying concentrations of either procainamide (closed circles) or NaCl (open circles). Fluorescence anisotropy values were obtained, converted to fraction bound, and plotted against inhibitor concentration to calculate an IC50 value.