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Closed complex of the D-3-hydroxybutyrate dehydrogenase induced by an enantiomeric competitive inhibitor.

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タイトル: Closed complex of the D-3-hydroxybutyrate dehydrogenase induced by an enantiomeric competitive inhibitor.
著者: Nakashima, Kanako / Ito, Kiyoshi / Nakajima, Yoshitaka / Yamazawa, Ryuji / Miyakawa, Syunsuke / Yoshimoto, Tadashi
発行日: 2009年 4月
出版者: 日本生化学会
引用: Journal of biochemistry, 145(4), pp.467-479; 2009
抄録: D-3-Hydroxybutyrate dehydrogenase (HBDH) from Pseudomonas fragi showed a strict stereospecificity to the d-enantiomer of 3-hydroxybutyrate (d-3-HB) as a substrate. The l-enantiomer acts as a competitive inhibitor, with a K(i) value comparable to the K(m) value for d-3-HB. We have determined the crystal structures of the ternary complex of HBDH-NAD(+)-l-3-HB and the binary complex of HBDH-NAD(+). The former structure showed a so-called closed-form conformation, which is considered an active form for catalysis, while the latter stayed mostly in a open-form conformation. The determined structures along with the site-directed mutagenesis confirmed the substrate recognition mechanism that we proposed previously. The hydrogen bonding interaction between Gln196, located in the moving helix, and the carboxyl group of the substrate/inhibitor is important for the stable ternary complex formation. Finally, the crystal structures of the Thr190 mutants, T190S and T190A, indicate that the Thr190 is a key residue for the open-closed conformational change. T190S retained 37% of the activity. In T190A, however, the activity decreased to 0.1% that of the wild-type enzyme. Fixing the position of the hydroxyl group of Thr190 to form hydrogen bonds to the pyrophosphate moiety and the carboxamide of NAD(+) seems to be a significant factor for the open-closed conformational change.
キーワード: hydroxybutyrate dehydrogenase / short-chain dehydrogenase/reductase family / crystal structure / conformational change / substrate recognition
URI: http://hdl.handle.net/10069/22323
ISSN: 0021924X
DOI: 10.1093/jb/mvn186
PubMed ID: 19122202
権利: (c) The Authors 2009. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved
資料タイプ: Journal Article
原稿種類: author
出現コレクション:110 学術雑誌論文

引用URI : http://hdl.handle.net/10069/22323



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