Single-strand binding protein enhances fidelity of DNA synthesis in vitro

Proc Natl Acad Sci U S A. 1979 Dec;76(12):6331-5. doi: 10.1073/pnas.76.12.6331.


The effect of Escherichia coli single-strand binding protein on the accuracy of in vitro DNA synthesis has been determined by using two independent methods. By using the synthetic polynucleotide poly[d(A-T)] and measuring dGTP misincorporation or by using phi X174 DNA and measuring nucleotide substitutions, we found that binding protein increases the fidelity of DNA synthesis by as much as 10-fold. This increase is observed with DNA polymerases of divergent sources and is progressive with increasing concentration of binding protein. The increased accuracy observed with DNA polymerases lacking a 3' leads to 5' exonuclease points to a mechanism other than augmented proofreading. In accord with the properties of single-strand binding proteins, it is suggested that increased fidelity is a result of enhanced base selection by the DNA polymerase, resulting from increased rigidity of the template due to its interaction with binding protein.

Publication types

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

MeSH terms

  • Base Sequence
  • DNA Helicases / metabolism*
  • DNA Polymerase III / metabolism
  • DNA Replication*
  • DNA, Bacterial / metabolism
  • DNA, Single-Stranded / metabolism*
  • DNA-Directed DNA Polymerase / metabolism*
  • Escherichia coli / genetics
  • Nucleic Acid Conformation
  • Substrate Specificity
  • Templates, Genetic


  • DNA, Bacterial
  • DNA, Single-Stranded
  • DNA Polymerase III
  • DNA-Directed DNA Polymerase
  • DNA Helicases