FIGURE 13.

Proposed model of DrRecA mechanism in the cell. A, double-stranded genomic DNA is bound by DrRecA in a quiescent state. B, DNA damage, such as ionizing radiation, introduces ssDNA in the cell that activates the ATPase activity of DrRecA. C, ATP hydrolysis provides the energy for DNA homology search. D, presence of SSB triggers a transfer of DrRecA from dsDNA to ssDNA; E, initiates strand invasion and D-loop formation by DrRecA. F, DNA is synthesized by DNA polymerase I to reconstitute dsDNA. If additional ssDNA is present, the recombination cycle can start over again.