The excision of AP sites by the 3'-5' exonuclease activity of the Klenow fragment of Escherichia coli DNA polymerase I

FEBS Lett. 1984 Dec 10;178(2):223-7. doi: 10.1016/0014-5793(84)80605-5.

Abstract

The 3' AP endonucleases (class I) are said to hydrolyze the phosphodiester bond 3' to AP sites yielding 3'-OH and 5'-phosphate ends; on the other hand, the resulting 3' terminal AP site is not removed by the 3'-5' exonuclease activity of the Klenow fragment [1]. We show that AP sites in DNA are easily removed by the 3'-5' exonuclease activity of the Klenow fragment and that they are excised as deoxyribose-5-phosphate. It is suggested that the 3' AP endonucleases are perhaps not the hydrolases they are supposed to be.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA / metabolism
  • DNA Polymerase I / metabolism*
  • DNA-(Apurinic or Apyrimidinic Site) Lyase
  • Deoxyribonuclease IV (Phage T4-Induced)
  • Endodeoxyribonucleases / metabolism*
  • Escherichia coli / enzymology*
  • Escherichia coli Proteins*
  • Phosphates / metabolism
  • Phosphorus Radioisotopes
  • Substrate Specificity

Substances

  • Escherichia coli Proteins
  • Phosphates
  • Phosphorus Radioisotopes
  • DNA
  • DNA Polymerase I
  • Endodeoxyribonucleases
  • Deoxyribonuclease IV (Phage T4-Induced)
  • endonuclease IV, E coli
  • DNA-(Apurinic or Apyrimidinic Site) Lyase