ATP-independent loading of the proliferating cell nuclear antigen requires DNA ends

J Biol Chem. 1993 Sep 25;268(27):19923-6.


The proliferating cell nuclear antigen (PCNA) is a processivity subunit for eukaryotic DNA polymerase delta. We present biochemical evidence that yeast PCNA likely adopts a toroidal structure containing an inside cavity through which double-stranded DNA slides. A comparative study of DNA replication reactions on circular versus linear model substrates shows that PCNA can only interact productively with DNA polymerase delta if the substrate is linear. This combined with the observation that a large molar excess of PCNA is required for maximal stimulatory activity is consistent with a model in which PCNA slips onto the end of the DNA in an ATP-independent manner.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Triphosphate / metabolism*
  • Antigens, Neoplasm / metabolism
  • DNA Polymerase III
  • DNA Replication*
  • DNA Restriction Enzymes / metabolism
  • DNA, Circular / biosynthesis
  • DNA, Single-Stranded / biosynthesis*
  • DNA-Directed DNA Polymerase / metabolism
  • Kinetics
  • Models, Structural
  • Nuclear Proteins / metabolism*
  • Proliferating Cell Nuclear Antigen
  • Restriction Mapping
  • Saccharomyces cerevisiae / metabolism*


  • Antigens, Neoplasm
  • DNA, Circular
  • DNA, Single-Stranded
  • Nuclear Proteins
  • Proliferating Cell Nuclear Antigen
  • Adenosine Triphosphate
  • DNA Polymerase III
  • DNA-Directed DNA Polymerase
  • DNA Restriction Enzymes