DNA translocases. (a) Branch migration during double-stranded DNA translocation. The bacterial RuvA and RuvB proteins form a complex that binds to a four-armed DNA junction that often forms during recombination (a Holliday intermediate; see Chapter 13), and the RuvA protein binds to the junction itself. The RuvB protein is the translocase, propelling the DNA to the left and right, as shown (arrows). (b) Protein displacement during DNA translocation. Translocase proteins in both bacteria and eukaryotes displace proteins from nucleic acids.