Active site tightness and substrate fit in DNA replication

Annu Rev Biochem. 2002;71:191-219. doi: 10.1146/annurev.biochem.71.110601.135453. Epub 2001 Nov 9.


Various physicochemical factors influence DNA replication fidelity. Since it is now known that Watson-Crick hydrogen bonds are not necessary for efficient and selective replication of a base pair by DNA polymerase enzymes, a number of alternative physical factors have been examined to explain the efficiency of these enzymes. Among these factors are minor groove hydrogen bonding, base stacking, solvation, and steric effects. We discuss the concept of active site tightness in DNA polymerases, and consider how it might influence steric (size and shape) effects of nucleotide selection in synthesis of a base pair. A high level of active site tightness is expected to lead to higher fidelity relative to proteins with looser active sites. We review the current data on what parts and dimensions of active sites are most affected by size and shape, based on data with modified nucleotides that have been examined as polymerase substrates. We also discuss recent data on nucleotide analogs displaying higher fidelity than the natural ones. The published data are discussed with a view toward testing this sterically based hypothesis and unifying existing observations into a narrowly defined range of effects.

Publication types

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

MeSH terms

  • Base Pairing*
  • Binding Sites
  • DNA / chemistry*
  • DNA / metabolism
  • DNA Replication*
  • DNA-Directed DNA Polymerase / chemistry
  • DNA-Directed DNA Polymerase / metabolism*
  • Hydrogen Bonding
  • Molecular Structure
  • Mutation
  • Nucleosides / chemistry*
  • Nucleosides / metabolism


  • Nucleosides
  • DNA
  • DNA-Directed DNA Polymerase