| Project/Area Number |
13480193
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural biochemistry
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| Research Institution | Osaka University |
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Principal Investigator |
KURAMITSU Seiki Osaka University, Graduate School of Science, Professor, 大学院・理学研究科, 教授 (60153368)
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| Co-Investigator(Kenkyū-buntansha) |
MASUI Ryoji MASUI,Ryoji, 大学院・理学研究科, 講師 (40252580)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥14,500,000 (Direct Cost: ¥14,500,000)
Fiscal Year 2003: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2002: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2001: ¥12,500,000 (Direct Cost: ¥12,500,000)
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| Keywords | DNA repair / damaged DNA / nucleotide / catalytic mechanism / substrate recognition / extreme thermophile / 酸化傷害DNA修復 / 8-オキソグアニン / MutM / フリップアウト / Thermus thermophilus HB8 / 立体構造反応解析 / 基質特異性 / 分子機能解析 |
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| Research Abstract |
DNA is oxidatively damaged by oxidative stress especially reactive oxygen species. Such damages result in mutations and cause a number of diseases including cancer. Among oxidatively damaged bases 8-oxoguanine can lead to increased frequency of G : C to T : A transversion. MutM is a base excision repair enzyme that recognize oxidatively damaged guanines including 8-oxoguanine. This enzyme catalyzes three reactions: excision of the 8-oxoguanine base (glycosylase activity). and b-and d-elimination of the resultant abasic site (AP-lyase activity), Recently, we also determined the structures of MutM-DNA complex. These structures suggest involvement of many amino acid residues in DNA-binding and catalytic activities. However, proposed roles of those residues have not been verified experimentally. To establish the detailed mechanism of MutM reaction, this study investigated functional roles of several amino acid residues in the catalysis. We selected several conserved residues based on the crystal structure of the complex and replaced them by other residues using site-directed mutagenesis. The obtained results demonstrate that some residues are involved in the catalytic reaction of MutM.
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