Abstract
The capacity of human poly(ADP-ribose) polymerase-1 (PARP-1) to interact with intact apurinic/apyrimidinic (AP) sites in DNA has been demonstrated. In cell extracts, sodium borohydride reduction of the PARP-1/AP site DNA complex resulted in covalent cross-linking of PARP-1 to DNA; the identity of cross-linked PARP-1 was confirmed by mass spectrometry. Using purified human PARP-1, the specificity of PARP-1 binding to AP site-containing DNA was confirmed in competition binding experiments. PARP-1 was only weakly activated to conduct poly(ADP-ribose) synthesis upon binding to AP site-containing DNA, but was strongly activated for poly(ADP-ribose) synthesis upon strand incision by AP endonuclease 1 (APE1). By virtue of its binding to AP sites, PARP-1 could be poised for its role in base excision repair, pending DNA strand incision by APE1 or the 5'-dRP/AP lyase activity in PARP-1.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Binding Sites
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Borohydrides / chemistry
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DNA / chemistry
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DNA / genetics
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DNA / metabolism*
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DNA Repair / physiology*
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DNA-(Apurinic or Apyrimidinic Site) Lyase / chemistry
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DNA-(Apurinic or Apyrimidinic Site) Lyase / genetics
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DNA-(Apurinic or Apyrimidinic Site) Lyase / metabolism*
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Enzyme Activation
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HeLa Cells
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Humans
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Oxidation-Reduction
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Poly (ADP-Ribose) Polymerase-1
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Poly Adenosine Diphosphate Ribose / chemistry
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Poly Adenosine Diphosphate Ribose / genetics
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Poly Adenosine Diphosphate Ribose / metabolism*
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Poly(ADP-ribose) Polymerases / chemistry
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Poly(ADP-ribose) Polymerases / genetics
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Poly(ADP-ribose) Polymerases / metabolism*
Substances
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Borohydrides
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Poly Adenosine Diphosphate Ribose
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sodium borohydride
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DNA
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PARP1 protein, human
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Poly (ADP-Ribose) Polymerase-1
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Poly(ADP-ribose) Polymerases
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APEX1 protein, human
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DNA-(Apurinic or Apyrimidinic Site) Lyase