Molecular Cell S

Sincludes the formation of a RecA-DNA filament, the search for homologous DNA sequences, the formation of a synapse, and the exchange of strands (Figure 1). In the first stage, RecAmono-20–30 bp (Sagi et al., 2006; Shen and Huang, 1986). This minimum efficient processing segment (MEPS) sets an upper limit to the size of each step. Examination of the effect ofmers polymerize along a single-stranded DNA (ssDNA) and form a nucleoprotein filament (NPF) (Figures 1A and 1B). Inside the mismatches on HR mediated by bacterial RecA and yeast Rad51 (Bucka and Stasiak, 2001; Holmes et al., 2001) suggestsful recombination requires the efficient detection of a target DNA within a vast pool of heterologous competitors. The proteins of the RecA superfamily, which includes RecA, RadA, Rad51, and DMC1, have been identified as the recombinases that can acti-vate HR. The conservation of structure and function throughout this family of recombinases allows the use of bacterial RecA as a model for protein-mediated HR (Bianco et al., 1998; Roc