The mechanism of the elongation and branching reaction of poly(ADP-ribose) polymerase as derived from crystal structures and mutagenesis

J Mol Biol. 1998 Apr 24;278(1):57-65. doi: 10.1006/jmbi.1998.1673.

Abstract

The binding site for the acceptor substrate poly(ADP-ribose) in the elongation reaction of the ADP-ribosyl transferase poly(ADP-ribose) polymerase (PARP) was detected by cocrystallizing the enzyme with an NAD+ analogue. The site was confirmed by mutagenesis studies. In conjunction with the binding site of the donor NAD+, the bound acceptor reveals the geometry of the elongation reaction. It shows in particular that the strictly conserved glutamate residue of all ADP-ribosylating enzymes (Glu988 of PARP) facilitates the reaction by polarizing both, donor and acceptor. Moreover, the binding properties of the acceptor site suggest a mechanism for the branching reaction, that also explains the dual specificity of this transferase for elongation and branching, which is unique among polymer-forming enzymes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Diphosphate Ribose / metabolism
  • Animals
  • Binding Sites
  • Chickens
  • Crystallography, X-Ray
  • Enzyme Inhibitors
  • Humans
  • Models, Molecular
  • Mutagenesis
  • NAD / analogs & derivatives*
  • NAD / chemistry
  • NAD / metabolism
  • Niacinamide / analogs & derivatives
  • Peptide Fragments / chemistry
  • Poly(ADP-ribose) Polymerase Inhibitors
  • Poly(ADP-ribose) Polymerases / chemistry*
  • Poly(ADP-ribose) Polymerases / genetics
  • Poly(ADP-ribose) Polymerases / metabolism*
  • Structure-Activity Relationship

Substances

  • Enzyme Inhibitors
  • Peptide Fragments
  • Poly(ADP-ribose) Polymerase Inhibitors
  • NAD
  • carbanicotinamide adenine dinucleotide
  • Adenosine Diphosphate Ribose
  • Niacinamide
  • Poly(ADP-ribose) Polymerases