| Project/Area Number |
13125207
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | Osaka City University |
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Principal Investigator |
HIROTSU Ken Osaka City University, Graduate School of Science, Osaka City University, Professor, 大学院・理学研究科, 教授 (10047269)
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| Co-Investigator(Kenkyū-buntansha) |
MORIMOTO Yukio Kyoto University, Research Reactor Institute, Professor, 原子炉実験所, 教授 (80200450)
MIYAHARA Ikuko Osaka City University, Graduate School of Science, Lecturer, 大学院・理学研究科, 講師 (40271176)
柴田 直樹 姫路工業大学, 大学院・理学研究科, 助手 (30295753)
安岡 則武 姫路工業大学, 理学部, 教授 (40029054)
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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 |
¥38,400,000 (Direct Cost: ¥38,400,000)
Fiscal Year 2003: ¥7,700,000 (Direct Cost: ¥7,700,000)
Fiscal Year 2002: ¥7,700,000 (Direct Cost: ¥7,700,000)
Fiscal Year 2001: ¥23,000,000 (Direct Cost: ¥23,000,000)
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| Keywords | composite blocatalyst / glutamine amidotransferase / quinoprotein / pyridoxal phosphate / flavin / X-ray Crystallography / コンポジット触媒 / PLP酵素 / トレオニン合成酵素 / グルタミンアミノ基転移酵素 / CTP合成酵素 / 基質認識 / 結晶構造 / X線結晶解析 / アルギニノコハク酸合成酵素 / グルタミンアミドトランスフェラーゼ / 高度好熱菌 / 分子内チャネル / フラビン依存型酵素 / アミノ基転移酵素 / キノプロテイン / フラビン依存型酸化酵素 / ビルトイン補酵素 |
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| Research Abstract |
High-resolution Structures of natural composite catalysts such as glutamine amidotransferase, and allosteric CTP synthetase, PLP-dependent enzymes, and FAD-dependent enzymes have been determined by X-ray crystallographic methods. The substrate recognition, induced fit, and reaction mechanism have been analyzed to understand the molecular design which enables these enzymes to act as biocatalysts.
1. Three-dimensional structures of natural biocatalysts and active-site designs. (1)Imidazole glycerol phosphate synthetase. The ammonia transfer mechanism through a molecular channel linking glutaminase and synthase sites has been proposed. (2)CTP (cytidine 5'-triphosphate) synthetase. The mechanism for ammonia tunneling, allosteric GTP activation, and enzyme activation induced by ATP and UTP-dependent conformational change has been examined. (3)Argininosuccinate synthetase. The substrate recognition mechanism and pseudo time-resolved X-ray analysis has been performed in order to clarify the st
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ereochemistry of the reaction. (4) Quinohemoprotein aminedehydrogenase. A novel quinine cofactor and highly unusual thioether cross-bridges have been identified.
2. Three-dimensional structures of PLP-dependent enzymes. (1)Histidinol-phosphate aminotransferase. The active-site design for double substrate recognition has been analyzed. (2)Branched-chain amino acid aminotransferase. The double substrate recognition and reaction mechanism have been elucidated. (3)Threonine synthase. The reaction catalyzed is expected to proceed through all the intermediates utilized by PLP-dependent enzymes. Stereochemistry of the reaction has been proposed. (4)Glutamine/kunerenine aminotransferase. In mammals, the enzyme is involved in CNS events. The substrate recognition and induced fit phenomena have been examined.
3. Three dimensional structures of FAD-dependent enzymes. (1)Medium-chain acyl-CoA oxidase. On the basis of structural comparison with the homologue (acyl-coA dehydrogenase), the molecular design of the oxidase has been analyzed. (2)Medium-chain acyl-CoA dehydrogenase as the transition state analogue. The transition state of the reaction has been examined based on the X-ray structure and MO calculation of the complex. Less
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