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Type: Journal article
Title: Rice family GH1 glycoside hydrolases with β-d-glucosidase and β-d-mannosidase activities
Other Titles: Rice family GH1 glycoside hydrolases with beta-d-glucosidase and beta-d-mannosidase activities
Author: Kuntothom, T.
Luang, S.
Harvey, A.
Fincher, G.
Opassiri, R.
Hrmova, M.
Cairns, J.
Citation: Archives of Biochemistry and Biophysics, 2009; 491(1-2):85-95
Publisher: Academic Press Inc
Issue Date: 2009
ISSN: 0003-9861
Statement of
Teerachai Kuntothom, Sukanya Luang, Andrew J. Harvey, Geoffrey B. Fincher, Rodjana Opassiri, Maria Hrmova, James R. Ketudat Cairns
Abstract: Plant beta-D-mannosidases and a rice beta-D-glucosidase, Os3BGlu7, with weak beta-D-mannosidase activity, cluster together in phylogenetic analysis. To investigate the relationship between substrate specificity and amino acid sequence similarity in family GH1 glycoside hydrolases, Os3BGlu8 and Os7BGlu26, putative rice beta-D-glucosidases from this cluster, and a beta-D-mannosidase from barley (rHvBII), were expressed in Escherichia coli and characterized. Os3BGlu8, the amino acid sequence and molecular model of which are most similar to Os3BGlu7, hydrolysed 4-nitrophenyl-beta-D-glucopyranoside (4NPGlc) faster than 4-nitrophenyl-beta-D-mannopyranoside (4NPMan), while Os7BGlu26, which is most similar to rHvBII by these criteria, hydrolysed 4NPMan faster than 4NPGlc. All the enzymes hydrolyzed cellooligosaccharides with increased hydrolytic rates as the degree of polymerization increased from 3-6, but only rHvBII hydrolyzed cellobiose with a higher k(cat)/K(m) value than cellotriose. This was primarily due to strong binding of glucosyl residues at the+2 subsite for the rice enzymes, and unfavorable interactions at this subsite with rHvBII.
Keywords: Hordeum vulgare; Oryza sativa; Molecular modelling; Phylogenetic analysis; Subsite mapping; Substrate specificity
Description: Copyright © 2009 Elsevier Inc. All rights reserved.
RMID: 0020093303
DOI: 10.1016/
Appears in Collections:Agriculture, Food and Wine publications

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