DNA mediated disassembly of hRad51 and hRad52 proteins and recruitment of hRad51 to ssDNA by hRad52

Purified human Rad51 and Rad52 proteins exhibit multiple oligomeric states, in vitro. Single-stranded DNA (ssDNA) renders high molecular weight aggregates of both proteins into smaller and soluble forms that include even the monomers. Consequently, these proteins that have a propensity to interact with each other's higher order forms by themselves, start interacting with monomeric forms in the presence of ssDNA, presumably reflecting the steps of protein assembly on DNA. In the same conditions, DNA binding assays reveal hRad52-mediated recruitment of hRad51 on ssDNA. Put together, these studies hint at DNA-induced disassembly of higher-order forms of Rad51 and Rad52 proteins as steps that precede protein assembly during hRad51 presynapsis on DNA, in vitro.