title: Rice Os9BGlu31 is a transglucosidase with the capacity to equilibrate phenylpropanoid, flavonoid, and phytohormone glycoconjugates.
abstract: Glycosylation is an important mechanism of controlling the reactivities and bioactivities of plant secondary metabolites and phytohormones. Rice (Oryza sativa) Os9BGlu31 is a glycoside hydrolase family GH1 transglycosidase that acts to transfer glucose between phenolic acids, phytohormones, and flavonoids. The highest activity was observed with the donors feruloyl-glucose, 4-coumaroyl-glucose, and sinapoyl-glucose, which are known to serve as donors in acyl and glucosyl transfer reactions in the vacuole, where Os9BGlu31 is localized. The free acids of these compounds also served as the best acceptors, suggesting that Os9BGlu31 may equilibrate the levels of phenolic acids and carboxylated phytohormones and their glucoconjugates. The Os9BGlu31 gene is most highly expressed in senescing flag leaf and developing seed and is induced in rice seedlings in response to drought stress and treatment with phytohormones, including abscisic acid, ethephon, methyljasmonate, 2,4-dichlorophenoxyacetic acid, and kinetin. Although site-directed mutagenesis of Os9BGlu31 indicated a function for the putative catalytic acid/base (Glu(169)), catalytic nucleophile residues (Glu(387)), and His(386), the wild type enzyme displays an unusual lack of inhibition by mechanism-based inhibitors of GH1 β-glucosidases that utilize a double displacement retaining mechanism.
authors: Institute of Science, Schools of Biochemistry and Chemistry, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
authors: Sukanya
authors: S
authors: Luang
authors: Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin 446-701, Korea.
authors: Jung-Il
authors: JI
authors: Cho
authors: Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin 446-701, Korea.
authors: Bancha
authors: B
authors: Mahong
authors: Institute of Science, Schools of Biochemistry and Chemistry, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
authors: Rodjana
authors: R
authors: Opassiri
authors: National Agricultural Research Center for Hokkaido Region, 1 Hitsujigaoka, Toyohira-ku, Sapporo, Hokkaido 062-8555, Japan.
authors: Takashi
authors: T
authors: Akiyama
authors: Institute of Science, Schools of Biochemistry and Chemistry, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
authors: Kannika
authors: K
authors: Phasai
authors: Institute of Science, Schools of Biochemistry and Chemistry, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
authors: Juthamath
authors: J
authors: Komvongsa
authors: Department of Biotechnology and Life Science, Faculty of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan.
authors: Nobuhiro
authors: N
authors: Sasaki
authors: Institute of Science, Schools of Biochemistry and Chemistry, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand; Center for Scientific and Technological Equipment, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
authors: Yan-Ling
authors: YL
authors: Hua
authors: Department of Biotechnology and Life Science, Faculty of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan.
authors: Yuki
authors: Y
authors: Matsuba
authors: Department of Biotechnology and Life Science, Faculty of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan.
authors: Yoshihiro
authors: Y
authors: Ozeki
authors: Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin 446-701, Korea. Electronic address: jjeon@khu.ac.kr.
authors: Jong-Seong
authors: JS
authors: Jeon
authors: Institute of Science, Schools of Biochemistry and Chemistry, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand; Laboratory of Biochemistry, Chulabhorn Research Institute, Bangkok 10210, Thailand. Electronic address: cairns@sut.ac.th.
authors: James R Ketudat
authors: JRK
authors: Cairns
mesh_terms: D017360:Arabidopsis / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism; D005419:Flavonoids / Q000737:chemistry*; D018506:Gene Expression Regulation, Plant; D005947:Glucose / Q000737:chemistry; D005959:Glucosidases / Q000737:chemistry*; D006001:Glycoconjugates / Q000737:chemistry*; D016695:Glycosyltransferases / Q000737:chemistry* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D062385:Hydroxybenzoates / Q000737:chemistry; D007700:Kinetics; D008670:Metals / Q000737:chemistry; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D012275:Oryza / Q000201:enzymology*; D010937:Plant Growth Regulators / Q000737:chemistry* / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D005419:Flavonoids; D006001:Glycoconjugates; D062385:Hydroxybenzoates; D008670:Metals; D010937:Plant Growth Regulators; D016695:Glycosyltransferases; D005959:Glucosidases; C017616:phenolic acid; D005947:Glucose