Rad51 and Dmc1 Recombinases
In eukaryotes, Rad51 and its meiosis-specific homologue Dmc1 (disrupted meiotic cDNA1) are key proteins of the homologous recombination (HR) pathway, which is responsible for the error-free repair of DNA double-strand breaks and faithful chromosome segregation. Rad51 and Dmc1 belong to the ubiquitous RecA protein family that is evolutionarily conserved from bacteria to humans. In vitro, Rad51 and Dmc1 show similar biochemical properties. Both proteins can bind ssDNA forming contiguous helical nucleoprotein filaments. The filaments promote the search for homologous dsDNA and DNA strand exchange between identical or nearly identical ssDNA and dsDNA strands, the basic step of homologous recombination. In addition, Rad51 and Dmc1 can promote branch migration of Holliday junctions through a distinct mechanism, which involves protein polymerization and dissociation on DNA. Both proteins bind...