Duplex DNA binding activity of the avian myeloblastosis virus DNA polymerase

Biochim Biophys Acta. 1981 Jan 29;652(1):29-38. doi: 10.1016/0005-2787(81)90205-7.


Purified avian myeloblastosis virus DNA polymerase has a strong binding affinity for closed circular double-stranded DNA with no 3'-hydroxy termini. Because of this affinity the DNA polymerase can retain labeled native ColE1 DNA on nitrocellulose filters. When the reaction contains four enzyme molecules per ColE1 molecule about 50% of the DNA is retained. Higher enzyme: DNA ratios cause retention of nearly 100% of the DNA. The binding activity comigrates with DNA synthetic activity through ion-exchange chromatography and glycerol gradient centrifugation, in indication that it is an intrinsic activity of the DNA polymerase. Escherichia coli DNA polymerase I and bacteriophage T4 DNA polymerase do not show this binding activity, which suggests that it is not a common property of DNA polymerases. A novel application of enzyme kinetics using endonuclease-treated DNA reveals the relative quantities of enzyme molecules which are synthesizing at 3'-termini vs. molecules bound to double-stranded regions. Heat stability measurements indicate that the polymerizing activity of the enzyme can be almost completely eliminated while about half of the original binding activity is retained.

Publication types

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

MeSH terms

  • Avian Leukosis Virus / enzymology*
  • Avian Myeloblastosis Virus / enzymology*
  • Centrifugation, Density Gradient
  • Chromatography, Ion Exchange
  • DNA Polymerase I / metabolism
  • DNA, Superhelical / metabolism*
  • DNA-Directed DNA Polymerase / metabolism*
  • DNA-Directed RNA Polymerases / metabolism
  • Escherichia coli / enzymology
  • T-Phages / enzymology


  • DNA, Superhelical
  • DNA-Directed RNA Polymerases
  • DNA Polymerase I
  • DNA-Directed DNA Polymerase