title: Two DNA polymerase sliding clamps from the thermophilic archaeon Sulfolobus solfataricus.
abstract: Herein, we report the identification and characterization of two DNA polymerase processivity factors from the thermoacidophilic archaeon Sulfolobus solfataricus. They, referred to as 039p (244 amino acid residues, 27 kDa) and 048p (249 amino acid residues, 27 kDa), present significant primary structure similarity to eukaryotic proliferating cell nuclear antigen (PCNA). We demonstrate that both 039p and 048p form oligomers in solution and are able to substantially activate the synthetic activity of the single-subunit family B DNA polymerase from S. solfataricus (Sso DNA pol B1) on poly(dA)-oligo(dT) as a primer-template. This stimulatory effect is the result of enhanced DNA polymerase processivity, as indicated by the analysis of the elongation products on polyacrylamide gels. Activation of Sso DNA pol B1 synthetic activity was also observed on linear primed single-stranded M13 mp18 DNA as a template. By immunoblot analysis using specific rabbit antisera, 039p and 048p were both detected in the logarithmic and stationary phases of S. solfataricus growth curve. This is the first report of the identification and biochemical characterization of two distinct DNA polymerase processivity factors from the same organism. The significance of these findings for the understanding of the DNA replication process in Archaea is discussed.
authors.affiliation: Istituto di Biochimica delle Proteine ed Enzimologia, Via G. Marconi, Napoli, 10. 80125, Italy.
authors.forename: M
authors.initials: M
authors.lastname: De Felice
authors.forename: C W
authors.initials: CW
authors.lastname: Sensen
authors.forename: R L
authors.initials: RL
authors.lastname: Charlebois
authors.forename: M
authors.initials: M
authors.lastname: Rossi
authors.forename: F M
authors.initials: FM
authors.lastname: Pisani
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019843:Archaeal Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003001:Cloning, Molecular; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D004926:Escherichia coli; D006801:Humans; D008969:Molecular Sequence Data; D018809:Proliferating Cell Nuclear Antigen / Q000737:chemistry; D011817:Rabbits; D017386:Sequence Homology, Amino Acid; D016944:Sulfolobus / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism
chemical_list: C120912:039 protein, Sulfolobus solfataricus; C120913:048 protein, Sulfolobus solfataricus; D019843:Archaeal Proteins; D018809:Proliferating Cell Nuclear Antigen; D004259:DNA-Directed DNA Polymerase