Abstract
Eukaryotic DNA polymerase beta (pol beta) can catalyze DNA synthesis during base excision DNA repair. It is shown here that pol beta also catalyzes release of 5'-terminal deoxyribose phosphate (dRP) residues from incised apurinic-apyrimidinic sites, which are common intermediate products in base excision repair. The catalytic domain for this activity resides within an amino-terminal 8-kilodalton fragment of pol beta, which comprises a distinct structural domain of the enzyme. Magnesium is required for the release of dRP from double-stranded DNA but not from a single-stranded oligonucleotide. Analysis of the released products indicates that the excision reaction occurs by beta-elimination rather than hydrolysis.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Apurinic Acid
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Base Sequence
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Binding Sites
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DNA / metabolism*
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DNA Ligases / metabolism
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DNA Polymerase I / metabolism*
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DNA Repair*
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DNA-(Apurinic or Apyrimidinic Site) Lyase
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Deoxyribonuclease IV (Phage T4-Induced)
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Edetic Acid / pharmacology
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Hydrolysis
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Lyases / metabolism
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Molecular Sequence Data
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Polynucleotides
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Protein Structure, Tertiary
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Rats
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Ribosemonophosphates / metabolism*
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Xenopus laevis
Substances
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Polynucleotides
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Ribosemonophosphates
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apyrimidinic acid
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Apurinic Acid
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DNA
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Edetic Acid
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DNA Polymerase I
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Deoxyribonuclease IV (Phage T4-Induced)
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Lyases
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DNA-(Apurinic or Apyrimidinic Site) Lyase
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DNA Ligases