title: Solution structure, backbone dynamics, and association behavior of the C-terminal BRCT domain from the breast cancer-associated protein BRCA1.
abstract: BRCA1 is a tumor suppressor protein associated with breast and ovarian cancer. The C-terminal region of BRCA1 consists of two closely spaced BRCT domains which mediate essential biological functions, including regulation of transcription and control of cell-cycle progression by their interaction with phosphorylated effector proteins. Here we report the NMR structure of the isolated C-terminal BRCT domain (BRCT-c) from human BRCA1. BRCT-c is well-structured in solution, folding independently in the absence of its BRCT-n counterpart. Ultracentrifugation experiments and size exclusion chromatography reveal that BRCT-c exists as a monomer under near-physiological conditions. Dynamics measurements from NMR data show three loops which coincide with the most variable sequence regions in BRCT domains, to be genuinely flexible in solution. The solution structure of BRCT-c shows subtle conformational changes when compared to the crystal structure of BRCT-c in the tandem repeat of BRCA1. These affect sites involved in formation of the BRCT-n-BRCT-c interface and the binding to phosphoserine-containing peptides. The results suggest that the presence of native BRCT-n and a properly aligned BRCT-n-BRCT-c interface are essential if BRCT-c is to adopt a biologically active conformation. Structural consequences of cancer-associated mutations and biological implications of the dynamic behavior are discussed.
authors.affiliation: Max Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, D-13125 Berlin, Germany.
authors.forename: Olaf J
authors.initials: OJ
authors.lastname: Gaiser
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Ball
authors.forename: Peter
authors.initials: P
authors.lastname: Schmieder
authors.forename: Dietmar
authors.initials: D
authors.lastname: Leitner
authors.forename: Holger
authors.initials: H
authors.lastname: Strauss
authors.forename: Martin
authors.initials: M
authors.lastname: Wahl
authors.forename: Ronald
authors.initials: R
authors.lastname: Kühne
authors.forename: Hartmut
authors.initials: H
authors.lastname: Oschkinat
authors.forename: Udo
authors.initials: U
authors.lastname: Heinemann
mesh_terms: D000595:Amino Acid Sequence; D019313:BRCA1 Protein / Q000737:chemistry* / Q000378:metabolism; D002850:Chromatography, Gel; D019281:Dimerization; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
chemical_list: D019313:BRCA1 Protein