Illustration of RuvAB proteins in complex with a Holliday junction between homologous strands of DNA (deoxyribonucleic acid) from a Salmonella typhimurium bacterium. A Holliday junction forms during crossing over, a natural genetic process that occurs between homologous chromosomes and leads to the switching of genetic material between the chromosomes. This recombination increases the genetic variation in a population. RuvA and RuvB are part of the RuvABC complex of three proteins that mediate branch migration and resolve the Holliday junction created during homologous recombination in bacteria. RuvA binds DNA and RuvB is an ATPase, providing energy for the process.