title: Structure and mechanism of action of the BRCA2 breast cancer tumor suppressor.
abstract: Mutations in BRCA2 increase susceptibility to breast, ovarian and prostate cancers. The product of human BRCA2, BRCA2 protein, has a key role in the repair of DNA double-strand breaks and interstrand cross-links by RAD51-mediated homologous recombination. Here, we present a biochemical and structural characterization of full-length (3,418 amino acid) BRCA2, alone and in complex with RAD51. We show that BRCA2 facilitates nucleation of RAD51 filaments at multiple sites on single-stranded DNA. Three-dimensional EM reconstructions revealed that BRCA2 exists as a dimer and that two oppositely oriented sets of RAD51 molecules bind the dimer. Single-stranded DNA binds along the long axis of BRCA2, such that only one set of RAD51 monomers can form a productive complex with DNA and establish filament formation. Our data define the molecular mechanism by which this tumor suppressor facilitates RAD51-mediated homologous-recombinational repair.
authors.affiliation: Centre for Structural Biology, Imperial College, London, U.K.
authors.forename: Taha
authors.initials: T
authors.lastname: Shahid
authors.affiliation: London Research Institute, Clare Hall Laboratories, South Mimms, U.K.
authors.forename: Joanna
authors.initials: J
authors.lastname: Soroka
authors.affiliation: Centre for Structural Biology, Imperial College, London, U.K.
authors.forename: Eric
authors.initials: E
authors.lastname: Kong
authors.affiliation: London Research Institute, Clare Hall Laboratories, South Mimms, U.K.
authors.forename: Laurent
authors.initials: L
authors.lastname: Malivert
authors.affiliation: London Research Institute, Clare Hall Laboratories, South Mimms, U.K.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: McIlwraith
authors.affiliation: Centre for Structural Biology, Imperial College, London, U.K.
authors.forename: Tillman
authors.initials: T
authors.lastname: Pape
authors.affiliation: London Research Institute, Clare Hall Laboratories, South Mimms, U.K.
authors.forename: Stephen C
authors.initials: SC
authors.lastname: West
authors.affiliation: Centre for Structural Biology, Imperial College, London, U.K.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Zhang
mesh_terms: D024682:BRCA2 Protein / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D004277:DNA, Single-Stranded / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006367:HeLa Cells; D059765:Homologous Recombination; D006801:Humans; D008958:Models, Molecular; D011487:Protein Conformation; D055503:Protein Multimerization; D051135:Rad51 Recombinase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D024682:BRCA2 Protein; C551750:BRCA2 protein, human; D004277:DNA, Single-Stranded; D011994:Recombinant Proteins; C495153:RAD51 protein, human; D051135:Rad51 Recombinase