Figure 6.

The activities of the mixture of the ttPOLXc and ttPHP domains. The measurement conditions were the same as given in Figure 4 except for the use of domain mixture (containing 1 μM ttPOLXc and 1 μM ttPHP domains). (A) Metal ion dependence of polymerase activity. (B) Time course analysis of exonuclease activity against ssDNA and dsDNA. (C) Exonuclease assay with dNTPs. Reaction mixtures comprised 20 mM Tris–HCl, 20 mM KCl, 1 mM MnCl₂, 100 nM ttPolX or 1 μM domain mixture, 10 nM 5′-labeled 21F and indicated amount of dNTPs, pH 8.0, at 37°C. The reaction mixtures were incubated for 30 min at 37°C, and then analyzed by 20% denaturing PAGE (8 M urea), but the running time was longer than that in (B). Note that the concentration of the domain mixture was higher than that of ttPolX.