Valine 1532 of human BRC repeat 4 plays an important role in the interaction between BRCA2 and RAD51

The breast cancer susceptibility protein BRCA2 is essential for recombinational DNA repair. BRCA2 specifically binds to RAD51 via 8 BRC repeat motifs and delivers RAD51 to double-stranded DNA breaks. In this study, a mammalian two-hybrid assay and competitive ELISA showed that the interaction between BRC repeat 4 (BRC4) and RAD51 was strengthened by the substitution of a single BRC4 amino acid from valine to isoleucine (V1532I). However, the cancer-associated V1532F mutant exhibited very weak interaction with RAD51. This study used a comparative analysis of BRC4 between animal species to identify V1532 as an important residue that interacts with RAD51