Unexpected behavior of DNA polymerase Mu opposite template 8-oxo-7,8-dihydro-2′-guanosine
| Autor: | Katarzyna Bebenek, Andrea M. Kaminski, Kishore K. Chiruvella, Lars C. Pedersen, Thomas A. Kunkel, Dale A. Ramsden |
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| Rok vydání: | 2019 |
| Předmět: |
DNA Replication
DNA End-Joining Repair Ultraviolet Rays Stereochemistry Guanosine DNA-Directed DNA Polymerase DNA Ligase ATP 03 medical and health sciences chemistry.chemical_compound Adenosine Triphosphate Structural Biology Radiation Ionizing Genetics Humans Transferase DNA Breaks Double-Stranded Nucleotide Polymerase 030304 developmental biology chemistry.chemical_classification 0303 health sciences DNA ligase biology 030302 biochemistry & molecular biology Active site chemistry Mutagenesis biology.protein Reactive Oxygen Species DNA polymerase mu DNA DNA Damage |
| Zdroj: | Nucleic Acids Research. 47:9410-9422 |
| ISSN: | 1362-4962 0305-1048 |
| Popis: | DNA double-strand breaks (DSBs) resulting from reactive oxygen species generated by exposure to UV and ionizing radiation are characterized by clusters of lesions near break sites. Such complex DSBs are repaired slowly, and their persistence can have severe consequences for human health. We have therefore probed DNA break repair containing a template 8-oxo-7,8-dihydro-2′-guanosine (8OG) by Family X Polymerase μ (Pol μ) in steady-state kinetics and cell-based assays. Pol μ tolerates 8OG-containing template DNA substrates, and the filled products can be subsequently ligated by DNA Ligase IV during Nonhomologous end-joining. Furthermore, Pol μ exhibits a strong preference for mutagenic bypass of 8OG by insertion of adenine. Crystal structures reveal that the template 8OG is accommodated in the Pol μ active site with none of the DNA substrate distortions observed for Family X siblings Pols β or λ. Kinetic characterization of template 8OG bypass indicates that Pol μ inserts adenosine nucleotides with weak sugar selectivity and, given the high cellular concentration of ATP, likely performs its role in repair of complex 8OG-containing DSBs using ribonucleotides. |
| Databáze: | OpenAIRE |
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