徳島大学 教育・研究者情報データベース(EDB)

1. 郷田 秀一郎([長崎大学])

   役割	任意
   貢献度	任意
   学籍番号	推奨

2. (英) Kojima Masaki / (日) 小島 正樹 / (読) こじま まさき

   役割	任意
   貢献度	任意
   学籍番号	推奨

3. (英) Nishikawa Yoshimi / (日) 西川 良美 / (読) にしかわ よしみ

   役割	任意
   貢献度	任意
   学籍番号	推奨

4. (英) Kujo Chizu / (日) 公庄 千寿 / (読) くじょう ちず

   役割	任意
   貢献度	任意
   学籍番号	推奨

5. 川上 竜巳([徳島大学.大学院社会産業理工学研究部.生物資源産業学域.食料科学系.食料科学分野]/[徳島大学.生物資源産業学部])

   役割	任意
   貢献度	任意
   学籍番号	推奨

6. (英) Kuramitsu Seiki / (日) 倉光 成紀 / (読) くらみつ せいき

   役割	任意
   貢献度	任意
   学籍番号	推奨

7. 櫻庭 春彦

   役割	任意
   貢献度	任意
   学籍番号	推奨

8. (英) Hiragi Yuzuru / (日) 柊 弓絃 / (読) ひらぎ ゆずる

   役割	任意
   貢献度	任意
   学籍番号	推奨

9. 大島 敏久([九州大学])

   役割	任意
   貢献度	任意
   学籍番号	推奨

(英) Intersubunit Interaction Induced by Subunit Rearrangement Is Essential for the Catalytic Activity of the Hyperthermophilic Glutamate Dehydrogenase from Pyrobaculum islandicum.

(英) The specific activity of recombinant Pyrobaculum islandicum glutamate dehydrogenase (pis-GDH) expressed in Escherichia coli is much lower than that of the native enzyme. However, when the recombinant enzyme is heated at 90 degrees C or exposed to 5 M urea, the activity increases to a level comparable to that of the native enzyme. Small-angle X-ray scattering measurements revealed that the radius of gyration (R(g,z)) of the hexameric recombinant enzyme was reduced to 47 A from 55 A by either heat or urea, and that the final structure of the active enzyme is the same irrespective of the mechanism of activation. Activation was accompanied by a shift in the peaks of the Kratky plot, though the molecular mass of the enzyme was unchanged. The activation-induced decline in R(g,z) followed first-order kinetics, indicating that activation of the enzyme involved a transition between two states, which was confirmed by singular-value decomposition analysis. When the low-resolution structure of the recombinant enzyme was restored using ab initio modeling, we found it to possess no point symmetry, whereas the heat-activated enzyme possessed 32-point symmetry. In addition, a marked increase in the fluorescence emission was observed with addition of ANS to the inactive recombinant enzyme but not the active forms, indicating that upon activation hydrophobic residues on the surface of the recombinant protein moved to the interior. Taken together, these data strongly suggest that subunit rearrangement, i.e., a change in the quaternary structure of the hexameric recombinant pis-GDH, is essential for activation of the enzyme.

1. (英) Calorimetry, Differential Scanning
2. (英) Cloning, Molecular
3. (英) Enzyme Activation
4. (英) Glutamate Dehydrogenase
5. (英) Hot Temperature
6. (英) Hydrophobic and Hydrophilic Interactions
7. (英) Protein Structure, Quaternary
8. (英) Pyrobaculum
9. (英) Recombinant Proteins
10. (英) Urea
11. (英) X-Ray Diffraction

1. (英) Article.Affiliation: Department of Biological Science and Technology, Faculty of Engineering, The University of Tokushima, Minamijosanjimacho, Tokushima 770-8506, Japan.

2. (英) Article.PublicationTypeList.PublicationType: Journal Article

3. (英) Article.PublicationTypeList.PublicationType: Research Support, Non-U.S. Gov't