Figure 4. Kinetics of dATP incorporation onto 18/26-mer-dG^C8-N-ABA.

(A) Dpo4 (120 nM) was first preincubated with 5′-³²P-labeled 18/26-mer-dG^C8-N-ABA (30 nM), and was then rapidly mixed with increasing concentrations of dATP (50 µM, ●; 150 µM, ■; 300 µM, ♦; 500 µM, ▲; 700 µM, ●; 1000 µM, ■; 1600 µM, ♦) for the indicated times before being quenched. Each time course was fitted to Equation 2 to yield a k_obs. (B) the k_obs values were plotted against corresponding dATP concentrations and the plot was fit to Equation 3 to produce a k_p of 2.0 ± 0.4 s⁻¹ and a K_{d, dATP} of 2,200 ± 600 µM.