An interaction between DNA polymerase and helicase is essential for the high processivity of the bacteriophage T7 replisome

J Biol Chem. 2012 Nov 9;287(46):39050-60. doi: 10.1074/jbc.M112.410647. Epub 2012 Sep 12.


Synthesis of the leading DNA strand requires the coordinated activity of DNA polymerase and DNA helicase, whereas synthesis of the lagging strand involves interactions of these proteins with DNA primase. We present the first structural model of a bacteriophage T7 DNA helicase-DNA polymerase complex using a combination of small angle x-ray scattering, single-molecule, and biochemical methods. We propose that the protein-protein interface stabilizing the leading strand synthesis involves two distinct interactions: a stable binding of the helicase to the palm domain of the polymerase and an electrostatic binding of the carboxyl-terminal tail of the helicase to a basic patch on the polymerase. DNA primase facilitates binding of DNA helicase to ssDNA and contributes to formation of the DNA helicase-DNA polymerase complex by stabilizing DNA helicase.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Bacteriophage T7 / genetics*
  • Catalysis
  • DNA Helicases / chemistry*
  • DNA Replication
  • DNA, Single-Stranded / genetics
  • DNA-Directed DNA Polymerase / chemistry*
  • Kinetics
  • Microscopy, Electron / methods
  • Models, Molecular
  • Protein Conformation
  • Protein Structure, Tertiary
  • Scattering, Radiation
  • Surface Plasmon Resonance
  • Ultracentrifugation
  • Viral Proteins / chemistry
  • Virus Replication*
  • X-Rays


  • DNA, Single-Stranded
  • Viral Proteins
  • DNA-Directed DNA Polymerase
  • DNA Helicases