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ツゲ ヒデアキ
TSUGE HIDEAKI
津下 英明 所属 京都産業大学 生命科学部 先端生命科学科 職種 教授 |
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| 言語種別 | 英語 |
| 発行・発表の年月 | 2005/01 |
| 形態種別 | 研究論文 |
| 査読 | 査読あり |
| 標題 | The first crystal structure of hyperthermostable NAD-dependent glutamate dehydrogenase from Pyrobaculum islandicum |
| 執筆形態 | その他 |
| 掲載誌名 | JOURNAL OF MOLECULAR BIOLOGY |
| 出版社・発行元 | ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD |
| 巻・号・頁 | 345(2),pp.325-337 |
| 担当区分 | 最終著者,責任著者 |
| 著者・共著者 | MW Bhuiya,H Sakuraba,T Ohshima,T Imagawa,N Katunuma,H Tsuge |
| 概要 | The extremely thermostable NAD-dependent glutamate dehydrogenase (NAD-GluDH) from Pyrobaculum islandicum, a member of the Crenarchaeota, was crystallized, and its 3D structure has been determined by X-ray diffraction methods. The homohexameric structure of Pb. islandicum glutamate dehydrogenase (Pis-GluDH) was solved and refined at a resolution of 2.9 Angstrom with a crystallographic R-factor of 19.9% (R-free 26.0%). The structure indicates that each subunit consists of two domains separated by a deep cleft containing an active site. The secondary structural elements and catalytically important residues of the enzyme were highly conserved among the NAD(P)-dependent GluDHs from other sources. A structural comparison of Pis-GluDH with other NAD(P)-dependent GluDHs suggests that a significant difference in the alpha8-loop-alpha9 region of this enzyme is associated with its coenzyme specificity. From the analysis of the 3D structure, hydrophobic interactions between intersubunits were found to be important features for the enzyme oligomerization. It has been reported that Pis-GluDH is highly thermostable, like the GluDH of the hyperthermophilic archaeum. Pyrococcus furiosus, and the increase in the intersubunit ion pair networks is responsible for the extreme thermostability of the Pc. furiosus enzyme. However, the number of intersubunit ion pairs in the Pis-GluDH molecules is much smaller than those of the Pc. furiosus GluDH. The number of hydrophobic interactions at the intersubunit interfaces were increased and responsible for the extremely high thermostability. This indicates that the major molecular strategy for high thermostability of the GluDHs may be different for each hyperthermophile. (C) 2004 Elsevier Ltd. All rights reserved. |
| DOI | 10.1016/j.jmb.2004.10.063 |
| ISSN | 0022-2836 |