title: Structural basis of human PCNA sliding on DNA.
abstract: Sliding clamps encircle DNA and tether polymerases and other factors to the genomic template. However, the molecular mechanism of clamp sliding on DNA is unknown. Using crystallography, NMR and molecular dynamics simulations, here we show that the human clamp PCNA recognizes DNA through a double patch of basic residues within the ring channel, arranged in a right-hand spiral that matches the pitch of B-DNA. We propose that PCNA slides by tracking the DNA backbone via a 'cogwheel' mechanism based on short-lived polar interactions, which keep the orientation of the clamp invariant relative to DNA. Mutation of residues at the PCNA-DNA interface has been shown to impair the initiation of DNA synthesis by polymerase δ (pol δ). Therefore, our findings suggest that a clamp correctly oriented on DNA is necessary for the assembly of a replication-competent PCNA-pol δ holoenzyme.
authors.affiliation: Structural Biology Laboratory, Elettra-Sincrotrone Trieste S.C.p.A., 34149 Trieste, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: De March
authors.affiliation: CIC bioGUNE, Parque Tecnologico de Bizkaia Edificio 800, 48160 Derio, Spain.
authors.forename: Nekane
authors.identifier: 0000-0003-0721-4813
authors.initials: N
authors.lastname: Merino
authors.affiliation: Institute of Advanced Chemistry of Catalonia (IQAC), CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain.
authors.forename: Susana
authors.identifier: 0000-0003-4868-6593
authors.initials: S
authors.lastname: Barrera-Vilarmau
authors.affiliation: Institute of Advanced Chemistry of Catalonia (IQAC), CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain.
authors.forename: Ramon
authors.identifier: 0000-0002-6687-382X
authors.initials: R
authors.lastname: Crehuet
authors.affiliation: Structural Biology Laboratory, Elettra-Sincrotrone Trieste S.C.p.A., 34149 Trieste, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Onesti
authors.affiliation: CIC bioGUNE, Parque Tecnologico de Bizkaia Edificio 800, 48160 Derio, Spain.|IKERBASQUE, Basque Foundation for Science, Bilbao 48013, Spain.
authors.forename: Francisco J
authors.identifier: 0000-0003-2545-4319
authors.initials: FJ
authors.lastname: Blanco
authors.affiliation: Structural Biology Laboratory, Elettra-Sincrotrone Trieste S.C.p.A., 34149 Trieste, Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: De Biasio
mesh_terms: D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D004258:DNA Polymerase III / Q000737:chemistry / Q000378:metabolism; D004261:DNA Replication; D059371:DNA, B-Form / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D009154:Mutation; D018809:Proliferating Cell Nuclear Antigen / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D059371:DNA, B-Form; D018809:Proliferating Cell Nuclear Antigen; D004247:DNA; D004258:DNA Polymerase III