2DGA

Crystal structure of hexameric beta-glucosidase in wheat

2DGA の概要

• エントリーDOI: 10.2210/pdb2dga/pdb
• 分子名称: Beta-glucosidase, SULFATE ION, GLYCEROL, ... (4 entities in total)
• 機能のキーワード: alpha/beta barrel, hydrolase
• 由来する生物種: Triticum aestivum (bread wheat)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 64538.92

構造登録者

Sue, M.,Yamazaki, K.,Miyamoto, T.,Yajima, S. (登録日: 2006-03-10, 公開日: 2006-07-04, 最終更新日: 2024-11-20)

主引用文献

Sue, M.,Yamazaki, K.,Yajima, S.,Nomura, T.,Matsukawa, T.,Iwamura, H.,Miyamoto, T.
Molecular and Structural Characterization of Hexameric beta-D-Glucosidases in Wheat and Rye.
Plant Physiol., 141:1237-1247, 2006

PubMed Abstract: The wheat (Triticum aestivum) and rye (Secale cereale) beta-D-glucosidases hydrolyze hydroxamic acid-glucose conjugates, exist as different types of isozyme, and function as oligomers. In this study, three cDNAs encoding beta-D-glucosidases (TaGlu1a, TaGlu1b, and TaGlu1c) were isolated from young wheat shoots. Although the TaGlu1s share very high sequence homology, the mRNA level of Taglu1c was much lower than the other two genes in 48- and 96-h-old wheat shoots. The expression ratio of each gene was different between two wheat cultivars. Recombinant TaGlu1b expressed in Escherichia coli was electrophoretically distinct fromTaGlu1a and TaGlu1c. Furthermore, coexpression of TaGlu1a and TaGlu1b gave seven bands on a native-PAGE gel, indicating the formation of both homo- and heterohexamers. One distinctive property of the wheat and rye glucosidases is that they function as hexamers but lose activity when dissociated into smaller oligomers or monomers. The crystal structure of hexameric TaGlu1b was determined at a resolution of 1.8 A. The N-terminal region was located at the dimer-dimer interface and plays a crucial role in hexamer formation. Mutational analyses revealed that the aromatic side chain at position 378, which is located at the entrance to the catalytic center, plays an important role in substrate binding. Additionally, serine-464 and leucine-465 of TaGlu1a were shown to be critical in the relative specificity for DIMBOA-glucose (2-O-beta-D-glucopyranosyl-4-hydroxy-7-methoxy-1,4-benzoxazin-3-one) over DIBOA-glucose (7-demethoxy-DIMBOA-glucose).

PubMed: 16751439
DOI: 10.1104/pp.106.077693

実験手法

X-RAY DIFFRACTION (1.8 Å)