XRCC3, also known as RAD51-like, belongs to the RecA family and RAD51 subfamily. It participates in homologous recombination to maintain chromosome stability and repair DNA damage. This protein functionally complements Chinese hamster irs1SF, a repair-deficient mutant that exhibits hypersensitivity to a number of different DNA-damaging agents and is chromosomally unstable. Recombinant human XRCC3 protein, fused to His-tag at N-terminus, was expressed in E.coli.