title: Structural basis of BACH1 phosphopeptide recognition by BRCA1 tandem BRCT domains.
abstract: BRCT tandem domains, found in many proteins involved in DNA damage checkpoint and DNA repair pathways, were recently shown to be phosphopeptide binding motifs. Using solution nuclear magnetic resonance (NMR) spectroscopy and mutational analysis, we have characterized the interaction of BRCA1-BRCT domains with a phosphoserine-containing peptide derived from the DNA repair helicase BACH1. We show that a phenylalanine in the +3 position from the phosphoserine of BACH1 is bound to a conserved hydrophobic pocket formed between the two BRCT domains and that recognition of the phosphate group is mediated by lysine and serine side chains from the amino-terminal BRCT domain. Mutations that prevent phosphopeptide binding abolish BRCA1 function in DNA damage-induced checkpoint control. Our NMR data also reveal a dynamic interaction between BRCA1-BRCT and BACH1, where the bound phosphopeptide exists as an equilibrium of two conformations and where BRCA1-BRCT undergoes a transition to a more rigid conformation upon peptide binding.
authors.affiliation: Department of Biochemistry and Molecular Biology, Mayo Clinic and Foundation, 200 First Street S.W., Rochester, MN 55905 USA.
authors.forename: Maria Victoria E
authors.initials: MV
authors.lastname: Botuyan
authors.forename: Yves
authors.initials: Y
authors.lastname: Nominé
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Yu
authors.forename: Nenad
authors.initials: N
authors.lastname: Juranic
authors.forename: Slobodan
authors.initials: S
authors.lastname: Macura
authors.forename: Junjie
authors.initials: J
authors.lastname: Chen
authors.forename: Georges
authors.initials: G
authors.lastname: Mer
mesh_terms: D019313:BRCA1 Protein / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D050976:Basic-Leucine Zipper Transcription Factors; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism; D003470:Culture Media; D004252:DNA Mutational Analysis; D051856:Fanconi Anemia Complementation Group Proteins; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D009154:Mutation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: C102108:BACH1 protein, human; D019313:BRCA1 Protein; D050976:Basic-Leucine Zipper Transcription Factors; D002352:Carrier Proteins; D003470:Culture Media; D051856:Fanconi Anemia Complementation Group Proteins; D014157:Transcription Factors