| Nonspecific DNA binding and coordination of the first two steps of base excision repair. | |
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MedLine Citation:
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PMID: 20701268 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The base excision repair (BER) pathway repairs a wide variety of damaged nucleobases in DNA. This pathway is initiated by a DNA repair glycosylase, which locates the site of damage and catalyzes the excision of the damaged nucleobase. The resulting abasic site is further processed by apurinic/apyrimidinic site endonuclease 1 (APE1) to create a single-strand nick with the 3'-hydroxyl that serves as a primer for DNA repair synthesis. Because an abasic site is highly mutagenic, it is critical that the steps of the BER pathway be coordinated. Most human glycosylases bind tightly to their abasic product. APE1 displaces the bound glycosylase, thereby stimulating multiple-turnover base excision. It has been proposed that direct protein-protein interactions are involved in the stimulation by APE1, but no common interaction motifs have been identified among the glycosylases that are stimulated by APE1. We characterized the APE1 stimulation of alkyladenine DNA glycosylase (AAG) using a variety of symmetric and asymmetric lesion-containing oligonucleotides. Efficient stimulation of a wide variety of substrates favors a model in which both AAG and APE1 can simultaneously bind to DNA but may not interact directly. Rather, nonspecific DNA binding by both AAG and APE1 enables APE1 to replace AAG at the abasic site. AAG is not displaced into solution but remains bound to an adjacent undamaged site. We propose that nonspecific DNA binding interactions allow transient exposure of the abasic site so that it can be captured by APE1. |
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Authors:
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Michael R Baldwin; Patrick J O'Brien |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural |
Journal Detail:
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Title: Biochemistry Volume: 49 ISSN: 1520-4995 ISO Abbreviation: Biochemistry Publication Date: 2010 Sep |
Date Detail:
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Created Date: 2010-09-07 Completed Date: 2010-11-03 Revised Date: 2012-04-26 |
Medline Journal Info:
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Nlm Unique ID: 0370623 Medline TA: Biochemistry Country: United States |
Other Details:
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Languages: eng Pagination: 7879-91 Citation Subset: IM |
Affiliation:
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Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Base Sequence DNA / metabolism DNA Damage DNA Glycosylases / chemistry, metabolism* DNA Repair* DNA-(Apurinic or Apyrimidinic Site) Lyase / chemistry, metabolism* DNA-Binding Proteins / chemistry, metabolism* Humans Models, Molecular Molecular Sequence Data Protein Conformation |
| Grant Support | |
ID/Acronym/Agency:
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CA122254/CA/NCI NIH HHS; R01 CA122254-03/CA/NCI NIH HHS; R01 CA122254-05/CA/NCI NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/DNA-Binding Proteins; 9007-49-2/DNA; EC 3.2.2.-/3-methyladenine-DNA glycosylase; EC 3.2.2.-/DNA Glycosylases; EC 4.2.99.18/APEX1 protein, human; EC 4.2.99.18/DNA-(Apurinic or Apyrimidinic Site) Lyase |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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