reca's association with dna major is based on its central role in homologous recombination. the reca protein binds strongly and in long clusters to ssdna to form a nucleoprotein filament. the protein has more than one dna binding site, and thus can hold a single strand and double strand together. this feature makes it possible to catalyze a dna synapsis reaction between a dna double helix and a complementary region of single stranded dna. the reca-ssdna filament searches for sequence similarity along the dsdna.