title: Biochemical characterization of rhamnosyltransferase involved in biosynthesis of pectic rhamnogalacturonan I in plant cell wall.
abstract: The pectin in plant cell walls consists of three domains: homogalacturonan, rhamnogalacturonan (RG)-I, and RG-II. It is predicted that around 50 different glycosyltransferases are required for their biosynthesis. Among these, the activities of only a few glycosyltransferases have been detected because pectic oligosaccharides are not readily available for use as substrates. In this study, fluorogenic pyridylaminated RG-I-backbone oligosaccharides (PA-RGs) with 3-14 degrees of polymerization (DP) were prepared. Using these oligosaccharides, the activity of RG-I:rhamnosyltransferase (RRT), involved in the biosynthesis of the RG-I backbone diglycosyl repeating units (-4GalUAα1-2Rhaα1-), was detected from the microsomes of azuki bean epicotyls. RRT was found to prefer longer acceptor substrates, PA-RGs with a DP > 7, and it does not require any metal ions for its activity. RRT is located in the Golgi and endoplasmic reticulum. The activity of RRT coincided with epicotyl growth, suggesting that RG-I biosynthesis is involved in plant growth.
authors.affiliation: College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Uehara
authors.affiliation: College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Tamura
authors.affiliation: College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan; Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Maki
authors.affiliation: College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
authors.forename: Kenta
authors.initials: K
authors.lastname: Yagyu
authors.affiliation: College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Mizoguchi
authors.affiliation: College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Tamiaki
authors.affiliation: Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto 611-0011, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Imai
authors.affiliation: Graduate School of Life and Environmental Sciences, Tsukuba University, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Ishii
authors.affiliation: International Center for Biotechnology, Osaka University, Suita, Osaka 565-0871, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Ohashi
authors.affiliation: International Center for Biotechnology, Osaka University, Suita, Osaka 565-0871, Japan.
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Fujiyama
authors.affiliation: College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan. Electronic address: ishimizu@fc.ritsumei.ac.jp.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ishimizu
mesh_terms: D055162:Biocatalysis; D002473:Cell Wall / Q000201:enzymology / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004721:Endoplasmic Reticulum / Q000201:enzymology / Q000378:metabolism; D016695:Glycosyltransferases / Q000378:metabolism*; D006056:Golgi Apparatus / Q000201:enzymology / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D009844:Oligosaccharides / Q000378:metabolism; D010368:Pectins / Q000096:biosynthesis*; D010940:Plant Proteins / Q000378:metabolism*; D013379:Substrate Specificity; D053719:Tandem Mass Spectrometry; D000070658:Vigna / Q000201:enzymology / Q000378:metabolism
chemical_list: D009844:Oligosaccharides; D010940:Plant Proteins; C042491:rhamnogalacturonan I; D010368:Pectins; D016695:Glycosyltransferases
keywords: Fluorescent labeling; Glycosyltransferase; Pectin; Plant cell wall; Rhamnogalacturonan I; Rhamnosyltransferase