An exonuclease activity associated with DNA polymerase I of Micrococcus radiodurans

Biochim Biophys Acta. 1978 Aug 23;520(1):122-30. doi: 10.1016/0005-2787(78)90013-8.

Abstract

An exonuclease activity is associated with one of three DNA polymerase in Micrococcus radiodurans. The nuclease activity co-sedimented with its DNA polymerase I of this bacterium on glycerol gradient centrifugation. Both activities show the same optimum pH and heat-inactivation kinetics. This nuclease hydrolyzes preferentially double-stranded DNA in an exonucleolytic manner from both ends of the duplex DNA. The products of hydrolysis are mostly deoxyribonucleoside 5'-monophosphate and no nucleosides are released into the acid-soluble fraction. Di- or other oligonucleotides are also produced but their relative amounts are constant during the time of incubation. The exonuclease activity requires Mg2+ and is inhibited by high concentrations of KCl as is DNA polymerase I of M. radiodurans.

MeSH terms

  • DNA Polymerase I / isolation & purification
  • DNA Polymerase I / metabolism*
  • DNA, Bacterial / metabolism
  • DNA-Directed DNA Polymerase / metabolism*
  • Deoxyribonucleases / metabolism
  • Exonucleases / isolation & purification
  • Exonucleases / metabolism*
  • Hot Temperature
  • Magnesium / pharmacology
  • Manganese / pharmacology
  • Micrococcus / enzymology*
  • Poly dA-dT / metabolism
  • Potassium Chloride / pharmacology
  • Thymine Nucleotides / metabolism

Substances

  • DNA, Bacterial
  • Thymine Nucleotides
  • Poly dA-dT
  • Manganese
  • Potassium Chloride
  • DNA Polymerase I
  • DNA-Directed DNA Polymerase
  • Deoxyribonucleases
  • Exonucleases
  • Magnesium