Biochemical characterisation of the clamp/clamp loader proteins from the euryarchaeon Archaeoglobus fulgidus

Nucleic Acids Res. 2002 Oct 15;30(20):4329-38. doi: 10.1093/nar/gkf584.

Abstract

Replicative polymerases of eukaryotes, prokaryotes and archaea obtain processivity using ring-shaped DNA sliding clamps that are loaded onto DNA by clamp loaders [replication factor C (RFC) in eukaryotes]. In this study, we cloned the two genes for the subunits of the RFC homologue of the euryarchaeon Archaeoglobus fulgidus. The proteins were expressed and purified from Escherichia coli both individually and as a complex. The afRFC subunits form a heteropentameric complex consisting of one copy of the large subunit and four copies of the small subunits. To analyse the functionality of afRFC, we also expressed the A.fulgidus PCNA homologue and a type B polymerase (PolB1) in E.coli. In primer extension assays, afRFC stimulated the processivity of afPolB1 in afPCNA-dependent reactions. Although the afRFC complex showed significant DNA-dependent ATPase activity, which could be further stimulated by afPCNA, neither of the isolated afRFC subunits showed this activity. However, both the large and small afRFC subunits showed interaction with afPCNA. Furthermore, we demonstrate that ATP binding, but not hydrolysis, is needed to stimulate interactions of the afRFC complex with afPCNA and DNA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / metabolism
  • Adenosine Triphosphate / metabolism
  • Archaeoglobus fulgidus / enzymology
  • Archaeoglobus fulgidus / genetics*
  • Archaeoglobus fulgidus / metabolism
  • Cloning, Molecular
  • DNA / biosynthesis
  • DNA / metabolism
  • DNA-Binding Proteins / chemistry*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • DNA-Directed DNA Polymerase / metabolism
  • Genes, Archaeal
  • Macromolecular Substances
  • Molecular Weight
  • Polynucleotides / metabolism
  • Proliferating Cell Nuclear Antigen / metabolism
  • Protein Subunits
  • RNA / metabolism
  • Replication Protein C
  • Substrate Specificity

Substances

  • DNA-Binding Proteins
  • Macromolecular Substances
  • Polynucleotides
  • Proliferating Cell Nuclear Antigen
  • Protein Subunits
  • RNA
  • Adenosine Triphosphate
  • DNA
  • DNA-Directed DNA Polymerase
  • Adenosine Triphosphatases
  • Replication Protein C