Crystal structure of the Holliday junction migration motor protein RuvB from Thermus thermophilus HB8

We report here the crystal structure of the RuvB motor protein from Thermus thermophilus HB8, which drives branch migration of the Holliday junction d uring homologous recombination. RuvB has a crescent-like architecture consi sting of three consecutive domains, the first two of which are involved in ATP binding and hydrolysis. DNA is likely to interact with a large basic cl eft, which encompasses the ATP-binding pocket and domain boundaries, wherea s the junction-recognition protein RuvA may bind a flexible beta -hairpin p rotruding from the N-terminal domain. The structures of two subunits, relat ed by a noncrystallographic pseudo-2-fold axis, imply that conformational c hanges of motor protein coupled with ATP hydrolysis may reflect motility es sential for its translocation around double-stranded DNA.