BRCA2DBD_OB3: A subfamily of OB folds corresponding to the third OB fold (OB3) of the 800-amino acid C-terminal ssDNA binding domain (DBD) of BRCA2 (breast cancer susceptibility gene 2) protein, called BRCA2DBD. BRCA2 participates in homologous recombination-mediated repair of double-strand DNA breaks. It stimulates the displacement of Replication protein A (RPA), the most abundant eukaryotic ssDNA binding protein. It also facilitates filament formation. Mutations that map throughout the BRCA2 protein are associated with breast cancer susceptibility. BRCA2 is a large nuclear protein and its most conserved region is the C-terminal BRCA2DBD. BRCA2DBD binds ssDNA in vitro, and is composed of five structural domains, three of which are OB folds (OB1, OB2, and OB3). BRCA2DBD OB2 and OB3 are arranged in tandem, and their mode of binding can be considered qualitatively similar to two OB folds of RPA1, DBD-A and DBD-B (the major DBDs of RPA).
Feature 1:ssDNA binding site [nucleic acid binding site]
Evidence:
Structure:1MJE_A; OB3 of human BRCA2 fragment (containing an internal deletion) binds oligo(dT)9; defined at 3.5A contacts.
Comment:BRCA2 is a large nuclear protein consisting five structural domains, three of which are OB folds (OB1, OB2, and OB3). OB2 contains an internal insertion named the tower domain. For the BRCA2 fragment in 1MJE_A, this insertion has been deleted.
Jiyao W et al.(2023). "The conserved domain database in 2023.",