 At recombination, two directly repeated res sites with resolvase dimers bound to each sub-site, come together to form a large complex structure called the synaptosome.Resolvase bound to sites II and III initiates the assembly of this complex.In this structure, exact architecture of which is still unclear, two res sites are intertwined in such a way as to juxtapose two copies of site I, allowing resolvase dimers bound to each site to form a tetramer.