Biochemical properties of a plastidial DNA polymerase of rice
| Autor: | Kengo Sakaguchi, Ai Saotome, Seisuke Kimura, Ryo Takeuchi |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
DNA Repair
DNA polymerase Recombinant Fusion Proteins DNA polymerase II Molecular Sequence Data DNA-Directed DNA Polymerase Plant Science Polymerase Chain Reaction DNA polymerase delta Bacterial Proteins Genetics Amino Acid Sequence Plastids Replication protein A Conserved Sequence Polymerase DNA Primers Plant Proteins DNA clamp Sequence Homology Amino Acid biology DNA replication Oryza General Medicine Molecular biology Kinetics Biochemistry biology.protein DNA polymerase I Agronomy and Crop Science |
| Zdroj: | Plant Molecular Biology. 64:601-611 |
| ISSN: | 1573-5028 0167-4412 |
| Popis: | Plastids are organelles unique to plant cells and are responsible for photosynthesis and other metabolic functions. Despite their important cellular roles, relatively little is known about the mechanism of plastidial DNA replication and repair. Recently, we identified a novel DNA polymerase in Oryza Sativa L. (OsPOLP1, formerly termed OsPolI-like) that is homologous to prokaryotic DNA polymerase Is (PolIs), and suggested that this polymerase might be involved in plastidial DNA replication and repair. Here, we propose to rename the plant PolI homologs as DNA polymerase pi (POLP), and investigate the biochemical properties of full-length OsPOLP1. The purified OsPOLP1 elongated both DNA and RNA primer hybridized to a DNA template, and possessed a 3' exonuclease activity. Moreover, OsPOLP1 displayed high processivity and fidelity, indicating that this polymerase has the biochemical characteristics appropriate for DNA replication. We found that POLPs have two extra sequences in the polymerase domain that are absent in prokaryotic PolIs. Deletion of either insert from OsPOLP1 caused a decrease in DNA synthetic activity, processivity, and DNA binding activity. In addition, OsPOLP1 efficiently catalyzed strand displacement on nicked DNA with a 5'-deoxyribose phosphate, suggesting that this enzyme might be involved in a repair pathway similar to long-patch base excision repair. These results provide insights into the possible role of POLPs in plastidial DNA replication and repair. |
| Databáze: | OpenAIRE |
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