2010年9月
Molecular identification of unsaturated uronate reductase prerequisite for alginate metabolism in Sphingomonas sp A1
BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS
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- 巻
- 1804
- 号
- 9
- 開始ページ
- 1925
- 終了ページ
- 1936
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1016/j.bbapap.2010.05.010
- 出版者・発行元
- ELSEVIER SCIENCE BV
In Sphingomonas sp. A1, alginate is degraded by alginate lyases to its constituent monosaccharides, which are nonenzymatically converted to an alpha-keto acid, namely, 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEH). The properties of the DEH-metabolizing enzyme and its gene in strain A1 were characterized. In the presence of alginate, strain A1 cells inducibly produced an NADPH-dependent DEH reductase (A1-R) in their cytoplasm. Molecular cloning of the enzyme gene indicated that A1-R belonged to the short-chain dehydrogenase/reductase superfamily and catalyzed the conversion of DEH to 2-keto-3-deoxy-D-gluconic acid most efficiently at around pH 7.0 and 50 degrees C. Crystal structures of A1-R and its complex with NADP were determined at around 1.6 angstrom resolution by X-ray crystallography. The enzyme consists of three layers (alpha/beta/alpha) , with a coenzyme-binding Rossmann fold. NADP is surrounded by positively charged residues, and Gly-38 and Arg-39 are crucial for NADP binding. Site-directed mutagenesis studies suggest that Ser-150, Tyr-164, and Lys-168 located around the Rossmann fold constitute the catalytic triad. To our knowledge, this is the first report on molecular cloning and structure determination of a bacterial DEH reductase responsible for alginate metabolism. (C) 2010 Elsevier B.V. All rights reserved.
- リンク情報
- ID情報
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- DOI : 10.1016/j.bbapap.2010.05.010
- ISSN : 1570-9639
- eISSN : 0006-3002
- Web of Science ID : WOS:000280976800027