title: A heterotrimeric PCNA in the hyperthermophilic archaeon Sulfolobus solfataricus.
abstract: The sliding clamp, PCNA, of the archaeon Sulfolobus solfataricus P2 is a heterotrimer of three distinct subunits (PCNA1, 2, and 3) that assembles in a defined manner. The PCNA heterotrimer, but not individual subunits, stimulates the activities of the DNA polymerase, DNA ligase I, and the flap endonuclease (FEN1) of S. solfataricus. Distinct PCNA subunits contact DNA polymerase, DNA ligase, or FEN1, imposing a defined architecture at the lagging strand fork and suggesting the existence of a preformed scanning complex at the fork. This provides a mechanism to tightly couple DNA synthesis and Okazaki fragment maturation. Additionally, unique subunit-specific interactions between components of the clamp loader, RFC, suggest a model for clamp loading of PCNA.
authors.affiliation: Medical Research Council Cancer Cell Unit, Hutchison MRC Research Centre, Hills Road, Cambridge CB2 2XZ, United Kingdom.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Dionne
authors.forename: Ravi K
authors.initials: RK
authors.lastname: Nookala
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Jackson
authors.forename: Aidan J
authors.initials: AJ
authors.lastname: Doherty
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Bell
mesh_terms: D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019641:DNA, Archaeal / Q000235:genetics / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D018809:Proliferating Cell Nuclear Antigen / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D021122:Protein Subunits / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016415:Sequence Alignment; D016944:Sulfolobus / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D019843:Archaeal Proteins; D019641:DNA, Archaeal; D018809:Proliferating Cell Nuclear Antigen; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; D004259:DNA-Directed DNA Polymerase