Fig. 6.

FtsK_C assembly, stoichiometry, translocation, and activation of recombination. (A) FtsK_C assembles stepwise on DNA into a single hexamer, which begins translocating around 0.25 s after the first binding. We note that in vivo FtsK_C is expected to assemble from monomers rather than trimers. (B) When FtsK_C arrives at a single dif site loaded with XerCD, it resides for around 0.5 s and then dissociates. (C) FtsK_C arrives at a preformed XerCD-dif synapsis, resides for 0.5–1 s, and then dissociates. Frequently, the synapsis then disassembles, but, occasionally, recombination is activated.