Reactions were carried out as described in Materials and Methods and as shown schematically in Figure 8A. (A) Timecourses of reactions containing a total of 7.50 μM RAD51 protein (WT and/or Q272L) at the indicated concentrations. The positions of SS, LDS, NC, and SC (supercoiled ϕX174 DNA) markers (lanes 1–3, 22–24) are indicated next to the gel, along with the position of JM products. Lanes 4–9: Reaction with WT only; Lanes 10–15: Reaction with Q272L only; Lanes 16–21: Reaction with 1:1 mixture of WT and Q272L. (B) Timecourses of reactions containing 3.75 μM WT RAD51 in the absence/presence of equimolar Q272L as indicated. Lanes 1–3, 18–20: Markers. Lanes 4–10: Reaction with WT only; Lanes 11–17: Reaction with mixture of WT and Q272L.