A Shuttle Mechanism for DNA-protein Interactions. The Regulation of poly(ADP-ribose) Polymerase

Eur J Biochem. 1982 Oct;127(3):579-85.


Previously it had been shown that poly(ADP-ribose) polymerase requires DNA for its activity and that this enzyme is auto-poly(ADP-ribosyl)ated. The studies reported here indicate that this self-modification inhibits the enzyme and decreases its affinity for DNA, as shown by sucrose gradient density centrifugation. The coupling of poly(ADP-ribose) polymerase with poly(ADP-ribose) glycohydrolase reactivates the polymerase by degrading poly(ADP-ribose) and restoring the polymerase-DNA complex. The assay of polymerase in the presence of glyco-hydrolase was made possible by use of a double-label assay involving release of 14C-labelled nicotinamide and the incorporation of 3H-labelled ADP-ribose from NAD+. These results provide the basis for a shuttle mechanism in which the polymerase can be moved on and off DNA by the action of these two enzymes. Mg2+ and histone H1 appear to activate the polymerase by increasing the affinity of the polymerase for DNA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cattle
  • Centrifugation, Density Gradient
  • DNA / metabolism*
  • Electrophoresis, Polyacrylamide Gel
  • Enzyme Activation / drug effects
  • Glycoside Hydrolases / metabolism
  • Histones / pharmacology
  • Magnesium / pharmacology
  • NAD+ Nucleosidase / metabolism*
  • Poly(ADP-ribose) Polymerase Inhibitors
  • Poly(ADP-ribose) Polymerases / metabolism*
  • Protein Binding
  • Thymus Gland / enzymology


  • Histones
  • Poly(ADP-ribose) Polymerase Inhibitors
  • DNA
  • Poly(ADP-ribose) Polymerases
  • Glycoside Hydrolases
  • poly ADP-ribose glycohydrolase
  • NAD+ Nucleosidase
  • Magnesium