The RuvA-RuvB complex in the presence of ATP renatures cruciform structure in supercoiled DNA with palindromic sequence, indicating that it may promote strand exchange reactions in homologous recombination. RuvAB is a helicase that mediates the Holliday junction migration by localized denaturation and reannealing. RuvB is a Mg(2+)-dependent, DNA-dependent ATPase with an equal preference for supercoiled and linear duplex DNA. It can promote Holliday junction migration alone. ATP + H2O = ADP + H(+) + phosphate The activity of RuvB is enhanced by RuvA. Optimum temperature is 70 degrees Celsius. Forms a complex with RuvA. Belongs to the RuvB family.