Replication of 2-hydroxyadenine-containing DNA and recognition by human MutSalpha

DNA Repair (Amst). 2007 Mar 1;6(3):355-66. doi: 10.1016/j.dnarep.2006.11.002. Epub 2006 Dec 26.


2-Hydroxyadenine (2-OH-A), a product of DNA oxidation, is a potential source of mutations. We investigated how representative DNA polymerases from the A, B and Y families dealt with 2-OH-A in primer extension experiments. A template 2-OH-A reduced the rate of incorporation by DNA polymerase alpha (Pol alpha) and Klenow fragment (Kf(exo-)). Two Y family DNA polymerases, human polymerase eta (Pol eta) and the archeal Dpo4 polymerase were affected differently. Bypass by Pol eta was very inefficient whereas Dpo4 efficiently replicated 2-OH-A. Replication of a template 2-OH-A by both enzymes was mutagenic and caused base substitutions. Dpo4 additionally introduced single base deletions. Thermodynamic analysis showed that 2-OH-A forms stable base pairs with T, C and G, and to a lesser extent with A. Oligonucleotides containing 2-OH-A base pairs, including the preferred 2-OH-A:T, were recognized by the human MutSalpha mismatch repair (MMR). MutSalpha also recognized 2-OH-A located in a repeat sequence that mimics a frameshift intermediate.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Pair Mismatch
  • Base Sequence
  • Cells, Cultured
  • DNA / chemistry
  • DNA / metabolism
  • DNA Mismatch Repair
  • DNA Polymerase I / metabolism
  • DNA Polymerase beta / metabolism
  • DNA Replication / physiology*
  • DNA-Binding Proteins / metabolism*
  • Guanine / metabolism*
  • HeLa Cells
  • Humans
  • Molecular Sequence Data
  • MutS Homolog 2 Protein / metabolism*
  • Nucleic Acid Conformation
  • Nucleic Acid Denaturation
  • Temperature
  • Thermodynamics
  • Tumor Cells, Cultured


  • DNA-Binding Proteins
  • G-T mismatch-binding protein
  • Guanine
  • DNA
  • isoguanine
  • DNA Polymerase I
  • DNA Polymerase beta
  • MSH2 protein, human
  • MutS Homolog 2 Protein