2dga
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Crystal structure of hexameric beta-glucosidase in wheat
OverviewOverview
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).
About this StructureAbout this Structure
2DGA is a Single protein structure of sequence from Triticum aestivum with and as ligands. Active as Beta-glucosidase, with EC number 3.2.1.21 Full crystallographic information is available from OCA.
ReferenceReference
Molecular and structural characterization of hexameric beta-D-glucosidases in wheat and rye., Sue M, Yamazaki K, Yajima S, Nomura T, Matsukawa T, Iwamura H, Miyamoto T, Plant Physiol. 2006 Aug;141(4):1237-47. Epub 2006 Jun 2. PMID:16751439
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