Figure 5.

Kinetics and nature of the heteroduplex DNA formation when single-strand exchange is initiated from a single 5′ or 3′ complementary overhanging end. ³²P-labeled pBluescript SK(+) circular ssDNA was incubated with Rad51 and RPA, and then pB422 linear dsDNA with a homologous 3′ or 5′ overhang at one end and a heterologous sequence at the other end of the complementary strand was added, and the reaction was sampled at 20 min and 4 hr. The direction and rate of heteroduplex DNA formation was determined by analyzing the specific fragments shown in Fig. 4 as described in Materials and Methods. The results are shown as the mol percent of circular ssDNA that appears in the fragments of the indicated sizes as they are located along the length of the heteroduplex DNA.