title: Structure of the heterotrimeric PCNA from Sulfolobus solfataricus.
abstract: PCNA is a ring-shaped protein that encircles DNA, providing a platform for the association of a wide variety of DNA-processing enzymes that utilize the PCNA sliding clamp to maintain proximity to their DNA substrates. PCNA is a homotrimer in eukaryotes, but a heterotrimer in crenarchaea such as Sulfolobus solfataricus. The three proteins are SsoPCNA1 (249 residues), SsoPCNA2 (245 residues) and SsoPCNA3 (259 residues). The heterotrimeric protein crystallizes in space group P2(1), with unit-cell parameters a = 44.8, b = 78.8, c = 125.6 A, beta = 100.5 degrees. The crystal structure of this heterotrimeric PCNA molecule has been solved using molecular replacement. The resulting structure to 2.3 A sheds light on the differential stabilities of the interactions observed between the three subunits and the specificity of individual subunits for partner proteins.
authors.affiliation: Centre for Biomolecular Science and The Scottish Structural Proteomics Facility, The University of St Andrews, Fife KY16 9RH, Scotland.
authors.forename: Gareth J
authors.initials: GJ
authors.lastname: Williams
authors.forename: Kenneth
authors.initials: K
authors.lastname: Johnson
authors.forename: Jana
authors.initials: J
authors.lastname: Rudolf
authors.forename: Stephen A
authors.initials: SA
authors.lastname: McMahon
authors.forename: Lester
authors.initials: L
authors.lastname: Carter
authors.forename: Muse
authors.initials: M
authors.lastname: Oke
authors.forename: Huanting
authors.initials: H
authors.lastname: Liu
authors.forename: Garry L
authors.initials: GL
authors.lastname: Taylor
authors.forename: Malcolm F
authors.initials: MF
authors.lastname: White
authors.forename: James H
authors.initials: JH
authors.lastname: Naismith
mesh_terms: D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D018809:Proliferating Cell Nuclear Antigen / Q000737:chemistry* / Q000235:genetics; D011487:Protein Conformation; D021122:Protein Subunits / Q000737:chemistry; D016415:Sequence Alignment; D048229:Sulfolobus solfataricus / Q000201:enzymology
chemical_list: D019843:Archaeal Proteins; D018809:Proliferating Cell Nuclear Antigen; D021122:Protein Subunits