Figure 4.

Impact of multiple mismatches on base triplet recognition. A, schematic illustration of dsDNA substrates bearing either two or three nucleotide mismatches within the penultimate triplet at the 3′ end of a 15-nt tract of microhomology. Corresponding binding data for RecA (B), Rad51 (C), and Dmc1 (D) are as indicated. Green, blue, and purple dashed lines correspond to the averaged binding stability for data obtained from the non-mismatched 9–11-nt substrates; the 12–14-nt substrates; and 15-nt substrates, respectively, reflecting steps 1–3 in A. Previously reported data for substrates bearing single mismatches are shown (open circles) for comparison (28).