title: 5' to 3' Unfolding Directionality of DNA Secondary Structures by Replication Protein A: G-QUADRUPLEXES AND DUPLEXES.
abstract: The replication protein A (RPA) is a single-stranded DNA-binding protein that plays an essential role in DNA metabolism. RPA is able to unfold G-quadruplex (G4) structures formed by telomeric DNA sequences, a function important for telomere maintenance. To elucidate the mechanism through which RPA unfolds telomeric G4s, we studied its interaction with oligonucleotides that adopt a G4 structure extended with a single-stranded tail on either side of the G4. Binding and unfolding was characterized using several biochemical and biophysical approaches and in the presence of specific G4 ligands, such as telomestatin and 360A. Our data show that RPA can bind on each side of the G4 but it unwinds the G4 only from 5' toward 3'. We explain the 5' to 3' unfolding directionality in terms of the 5' to 3' oriented laying out of hRPA subunits along single-stranded DNA. Furthermore, we demonstrate by kinetics experiments that RPA proceeds with the same directionality for duplex unfolding.
authors.affiliation: From the Structure et Instabilité des Génomes, Sorbonne Universités, Muséum National d'Histoire Naturelle, INSERM U1154, CNRS UMR 7196, CP26, 57 rue Cuvier, 75005, Paris, France, the Sorbonne Universités, UPMC University Paris 06, F-75005, Paris, France.
authors.forename: Layal
authors.initials: L
authors.lastname: Safa
authors.affiliation: the Laboratoire ARNA-INSERM U1212, UMR 5320, Institut européen de chimie et biologie, 2 rue Robert Escarpit, 33607 Pessac, France.
authors.forename: Nassima Meriem
authors.initials: NM
authors.lastname: Gueddouda
authors.affiliation: From the Structure et Instabilité des Génomes, Sorbonne Universités, Muséum National d'Histoire Naturelle, INSERM U1154, CNRS UMR 7196, CP26, 57 rue Cuvier, 75005, Paris, France, the Sorbonne Universités, UPMC University Paris 06, F-75005, Paris, France, the Ecole Normale Supérieure, PSL Research University, Département de Chimie, 24 rue Lhomond, CNRS, UMR 7203 LBM, 75005 Paris, France, and.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Thiébaut
authors.affiliation: From the Structure et Instabilité des Génomes, Sorbonne Universités, Muséum National d'Histoire Naturelle, INSERM U1154, CNRS UMR 7196, CP26, 57 rue Cuvier, 75005, Paris, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Delagoutte
authors.affiliation: the Novosibirsk Institute of Chemical Biology and Fundamental Medecine, Siberian Division of Russian Academy of Science, 630090 Novosibirsk, Russia.
authors.forename: Irina
authors.initials: I
authors.lastname: Petruseva
authors.affiliation: the Novosibirsk Institute of Chemical Biology and Fundamental Medecine, Siberian Division of Russian Academy of Science, 630090 Novosibirsk, Russia.
authors.forename: Olga
authors.initials: O
authors.lastname: Lavrik
authors.affiliation: the Laboratoire ARNA-INSERM U1212, UMR 5320, Institut européen de chimie et biologie, 2 rue Robert Escarpit, 33607 Pessac, France.
authors.forename: Oscar
authors.initials: O
authors.lastname: Mendoza
authors.affiliation: the Laboratoire ARNA-INSERM U1212, UMR 5320, Institut européen de chimie et biologie, 2 rue Robert Escarpit, 33607 Pessac, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Bourdoncle
authors.affiliation: From the Structure et Instabilité des Génomes, Sorbonne Universités, Muséum National d'Histoire Naturelle, INSERM U1154, CNRS UMR 7196, CP26, 57 rue Cuvier, 75005, Paris, France, alberti@mnhn.fr.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Alberti
authors.affiliation: From the Structure et Instabilité des Génomes, Sorbonne Universités, Muséum National d'Histoire Naturelle, INSERM U1154, CNRS UMR 7196, CP26, 57 rue Cuvier, 75005, Paris, France.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Riou
authors.affiliation: From the Structure et Instabilité des Génomes, Sorbonne Universités, Muséum National d'Histoire Naturelle, INSERM U1154, CNRS UMR 7196, CP26, 57 rue Cuvier, 75005, Paris, France, the Sorbonne Universités, UPMC University Paris 06, F-75005, Paris, France, carole.saintome@mnhn.fr.
authors.forename: Carole
authors.initials: C
authors.lastname: Saintomé
mesh_terms: D004277:DNA, Single-Stranded / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D054856:G-Quadruplexes; D006801:Humans; D010080:Oxazoles / Q000737:chemistry; D051716:Replication Protein A / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016615:Telomere / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D004277:DNA, Single-Stranded; D010080:Oxazoles; C497167:RPA1 protein, human; D051716:Replication Protein A; C431888:telomestatin
keywords: G-quadruplex; G4-ligand; fluorescence resonance energy transfer (FRET); gel electrophoresis; kinetics; replication protein A; telomere; unwinding polarity