Involved in the homologous recombination repair (HRR) pathway of double-stranded DNA breaks arising during DNA replication or induced by DNA-damaging agents. Bind to single-stranded DNA (ssDNA) and has DNA-dependent ATPase activity. Part of the RAD51 paralog protein complex BCDX2 which acts in the BRCA1-BRCA2-dependent HR pathway. Upon DNA damage, BCDX2 acts downstream of BRCA2 recruitment and upstream of RAD51 recruitment. BCDX2 binds predominantly to the intersection of the four duplex arms of the Holliday junction and to junction of replication forks. The BCDX2 complex was originally reported to bind single-stranded DNA, single-stranded gaps in duplex DNA and specifically to nicks in duplex DNA. Involved in telomere maintenance. The BCDX2 subcomplex XRCC2:RAD51D can stimulate Holliday junction resolution by BLM. Part of the BCDX2 complex consisting of RAD51B, RAD51C, RAD51D and XRCC2; the complex has a ring-like structure arranged into a flat disc around a central channel. In the absence of DNA, the BCDX2 subcomplex XRCC2:RAD51D formed a multimeric ring structure; in the presence of single-stranded DNA it formed a filamentous structure with the ssDNA. Interacts with SWSAP1 and ZSWIM7; involved in homologous recombination repair. Interacts with BLM; required for stimulation of BLM activity by the BCDX2 subcomplex XRCC2:RAD51D. Expressed in colon, prostate, spleen, testis, ovary, thymus and small intestine. Weakly expressed in leukocytes. Disease susceptibility is associated with variants affecting the gene represented in this entry. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay. Belongs to the RecA family. RAD51 subfamily.