title: BRCA1 RING domain cancer-predisposing mutations. Structural consequences and effects on protein-protein interactions.
abstract: Cancer-predisposing missense mutations in the RING domain of BRCA1 primarily target Zn(2+)-liganding residues. Here we report on the structural consequences of such mutations introduced into the second Zn(2+) site (Site II) of the BRCA1 RING domain and their effect on the interaction with the BARD1 RING domain. Each of the BRCA1 Site II mutants still interact and form a stable heterodimer with BARD1. Limited proteolysis of BRCA1/BARD1 complexes, monitored by matrix-assisted laser desorption ionization time-of-flight spectrometry, show that the mutations cause a local structural perturbation that is primarily confined to the second Zn(2+) binding loop of the BRCA1 subunit. These findings are consistent with the structure of the BRCA1/BARD1 heterodimer, which shows this region is well removed from the helices required for dimerization with BARD1. Instead, the mutations alter a region of BRCA1 that appears to be required for interaction with ubiquitin-conjugating enzymes.
authors.affiliation: Department of Biochemistry and Biomolecular Structure Center, University of Washington, Seattle Washington 98195-7742, USA.
authors.forename: P S
authors.initials: PS
authors.lastname: Brzovic
authors.forename: J E
authors.initials: JE
authors.lastname: Meza
authors.forename: M C
authors.initials: MC
authors.lastname: King
authors.forename: R E
authors.initials: RE
authors.lastname: Klevit
mesh_terms: D019313:BRCA1 Protein / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D019281:Dimerization; D020022:Genetic Predisposition to Disease; D006801:Humans; D006868:Hydrolysis; D008958:Models, Molecular; D020125:Mutation, Missense; D011485:Protein Binding; D011487:Protein Conformation; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D015032:Zinc / Q000378:metabolism
chemical_list: D019313:BRCA1 Protein; D015032:Zinc