title: p15PAF is an intrinsically disordered protein with nonrandom structural preferences at sites of interaction with other proteins.
abstract: We present to our knowledge the first structural characterization of the proliferating-cell-nuclear-antigen-associated factor p15(PAF), showing that it is monomeric and intrinsically disordered in solution but has nonrandom conformational preferences at sites of protein-protein interactions. p15(PAF) is a 12 kDa nuclear protein that acts as a regulator of DNA repair during DNA replication. The p15(PAF) gene is overexpressed in several types of human cancer. The nearly complete NMR backbone assignment of p15(PAF) allowed us to measure 86 N-H(N) residual dipolar couplings. Our residual dipolar coupling analysis reveals nonrandom conformational preferences in distinct regions, including the proliferating-cell-nuclear-antigen-interacting protein motif (PIP-box) and the KEN-box (recognized by the ubiquitin ligase that targets p15(PAF) for degradation). In accordance with these findings, analysis of the (15)N R2 relaxation rates shows a relatively reduced mobility for the residues in these regions. The agreement between the experimental small angle x-ray scattering curve of p15(PAF) and that computed from a statistical coil ensemble corrected for the presence of local secondary structural elements further validates our structural model for p15(PAF). The coincidence of these transiently structured regions with protein-protein interaction and posttranslational modification sites suggests a possible role for these structures as molecular recognition elements for p15(PAF).
authors.affiliation: Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC bioGUNE), Derio, Spain.
authors.forename: Alfredo
authors.initials: A
authors.lastname: De Biasio
authors.affiliation: Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC bioGUNE), Derio, Spain.
authors.forename: Alain
authors.initials: A
authors.lastname: Ibáñez de Opakua
authors.affiliation: Centre de Biochimie Structurale, Institut National de la Santé et de la Recherche Médicale (INSERM) U1054, Centre National de la Recherche Scientifique (CNRS) UMR 5048, Université Montpellier 1 and 2, Montpellier, France.
authors.forename: Tiago N
authors.initials: TN
authors.lastname: Cordeiro
authors.affiliation: Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC bioGUNE), Derio, Spain.
authors.forename: Maider
authors.initials: M
authors.lastname: Villate
authors.affiliation: Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC bioGUNE), Derio, Spain.
authors.forename: Nekane
authors.initials: N
authors.lastname: Merino
authors.affiliation: Centre de Biochimie Structurale, Institut National de la Santé et de la Recherche Médicale (INSERM) U1054, Centre National de la Recherche Scientifique (CNRS) UMR 5048, Université Montpellier 1 and 2, Montpellier, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Sibille
authors.affiliation: Centre de Résonance Magnétique Nucléaire à Très Hauts Champs, Institut de Sciences Analytiques (CNRS/Ecole Normale Supérieure de Lyon/Université Claude Bernard Lyon 1), Villeurbanne, France.
authors.forename: Moreno
authors.initials: M
authors.lastname: Lelli
authors.affiliation: Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC bioGUNE), Derio, Spain.
authors.forename: Tammo
authors.initials: T
authors.lastname: Diercks
authors.affiliation: Centre de Biochimie Structurale, Institut National de la Santé et de la Recherche Médicale (INSERM) U1054, Centre National de la Recherche Scientifique (CNRS) UMR 5048, Université Montpellier 1 and 2, Montpellier, France.
authors.forename: Pau
authors.initials: P
authors.lastname: Bernadó
authors.affiliation: Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC bioGUNE), Derio, Spain; IKERBASQUE, Basque Foundation for Science, Bilbao, Spain. Electronic address: fblanco@cicbiogune.es.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Blanco
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D004268:DNA-Binding Proteins; D006801:Humans; D008969:Molecular Sequence Data; D011485:Protein Binding
chemical_list: D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C425208:PCLAF protein, human