Figure 3.
Pol and dRP lyase activities cosediment. Homogenous, recombinant, His-tagged pol γ catalytic subunit (29 μg) was subjected to band sedimentation through 10–30% sucrose gradients as described in Materials and Methods. (A) The indicated gradient fractions (16 μl) were resolved by electrophoresis through 4–20% SDS/polyacrylamide gels and stained with Coomassie brilliant blue. The arrow indicates the position of the pol γ catalytic subunit. (B) Pol activity (□) and dRP lyase activity (•) were determined as described in Materials and Methods on 2-μl samples of the indicated gradient fractions. The peak positions of standard proteins (catalase, S20,w = 11.3 S; γ-globulin, S20,w = 7.1 S; ovalbumin, S20,w = 3.55 S) sedimented in a parallel gradient are shown.