FIGURE 2.

The directionality of strand exchange and stability of the dsDNA product of strand exchange do not influence Dmc1 strand exchange efficiency. A, chimeric DNA substrates used to study the directionality of the strand exchange. Nucleotides in bold show the 71% GC-rich region. T, TAMRA; C, Cy5. Sequences of the single-strand oligonucleotides, either RG1(−) (3′, 71% GC-rich) or RG2(−) (5′, 71% GC-rich), are 100% complementary to RG1(+)C or RG2(+)C, respectively. B and C, the kinetics of strand exchange promoted by Dmc1 or RecA with substrates shown in A. D and E, comparative analysis between the melting temperature of dsDNA formed by the Dmc1 strand exchange reaction (homologous or containing single mismatches) and relative strand exchange efficiency obtained during the strand exchange reaction promoted by Dmc1. Melting temperature for each duplex was calculated using the software “MELTING 5” (45). The superscripts in E indicate the corresponding Group (see Fig. 3A).