Repair of an apurinic or apyrimidinic site in DNA by AP endonuclease must be completed by the action of

Question

Quizplus · Accepted Answer

AP endonuclease cleaves the phosphodiester bond at the apurinic or apyrimidinic site, creating a gap with a 5' phosphate and a 3' hydroxyl group. DNA polymerase I can fill in this gap by adding nucleotides to the 3' end and removing the RNA primer at the 5' end. Therefore, repair of an apurinic or apyrimidinic site in DNA requires the action of DNA polymerase I. UvrABC endonuclease is involved in nucleotide excision repair, while RecA protein is involved in DNA repair by homologous recombination. Therefore, neither of these choices is correct for repairing an apurinic or apyrimidinic site.

Repair of an Apurinic or Apyrimidinic Site in DNA by AP