Figure 2.

Inhibition of strand displacement is not due to dissociation of the polymerase and is independent of the orientation of the flap. (a) Scheme depicting the experiments testing the effect of the 5′-flap on Pol δ^DV dissociation from the substrate. (b) Primer extension activity in Buffer TM (20 mM NaCl, 30°C) of the reference, labeled primed template by Pol δ^DV after incubation in the absence or presence of a 4-folf excess of the indicated unlabeled DNAs. (c) Strand displacement activity of Pol δ^DV in Buffer TM (20 mM NaCl, 30°C) using a T₇ gap substrate containing either a 5′-flap (1) or a 3′-flap (2) generated using oligonucleotides with a reverse polarity switch at the end of the flap. The 5 nt flaps are used to control for the effect of the change in polarity itself.