title: The architecture of an Okazaki fragment-processing holoenzyme from the archaeon Sulfolobus solfataricus.
abstract: DNA replication on the lagging strand occurs via the synthesis and maturation of Okazaki fragments. In archaea and eukaryotes, the enzymatic activities required for this process are supplied by a replicative DNA polymerase, Flap endonuclease 1 (Fen1) and DNA ligase 1 (Lig1). These factors interact with the sliding clamp PCNA (proliferating cell nuclear antigen) providing a potential means of co-ordinating their sequential actions within a higher order assembly. In hyperthermophilic archaea of the Sulfolobus genus, PCNA is a defined heterotrimeric assembly and each subunit interacts preferentially with specific client proteins. We have exploited this inherent asymmetry to assemble a PCNA-polymerase-Fen1-ligase complex on DNA and have visualized it by electron microscopy. Our studies reveal the structural basis of co-occupancy of a single PCNA ring by the three distinct client proteins.
authors.affiliation: *Institute of Structural and Molecular Biology, and Centre for Science at Extreme Conditions, University of Edinburgh, Edinburgh EH9 3JR, U.K.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Cannone
authors.affiliation: †Molecular and Cellular Biochemistry Department, Biology Department, Indiana University, Bloomington, IN 47405, U.S.A.
authors.forename: Yuli
authors.initials: Y
authors.lastname: Xu
authors.affiliation: ‡Sir William Dunn School of Pathology, Oxford University, Oxford OX1 3RE, U.K.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Beattie
authors.affiliation: †Molecular and Cellular Biochemistry Department, Biology Department, Indiana University, Bloomington, IN 47405, U.S.A.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Bell
authors.affiliation: *Institute of Structural and Molecular Biology, and Centre for Science at Extreme Conditions, University of Edinburgh, Edinburgh EH9 3JR, U.K.
authors.forename: Laura
authors.initials: L
authors.lastname: Spagnolo
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics; D000072481:DNA Ligase ATP; D011088:DNA Ligases / Q000737:chemistry* / Q000235:genetics; D045585:Flap Endonucleases / Q000737:chemistry* / Q000235:genetics; D046912:Multiprotein Complexes / Q000737:chemistry / Q000235:genetics / Q000648:ultrastructure; D018809:Proliferating Cell Nuclear Antigen / Q000737:chemistry* / Q000235:genetics; D048229:Sulfolobus solfataricus / Q000737:chemistry* / Q000235:genetics
chemical_list: D019843:Archaeal Proteins; D046912:Multiprotein Complexes; D018809:Proliferating Cell Nuclear Antigen; D045585:Flap Endonucleases; D011088:DNA Ligases; D000072481:DNA Ligase ATP