title: Glucuronic acid in Arabidopsis thaliana xylans carries a novel pentose substituent.
abstract: Glucuronic acids in Arabidopsis thaliana xylans exist in 4-O-methylated (MeGlcA) and non-methylated (GlcA) forms at a ratio of about 3:2. The matrix-assisted laser desorption/ionization mass spectrometry analysis of the endoxylanase liberated acidic oligosaccharides from the Arabidopsis inflorescence stem showed that two peaks with GlcA (GlcA-Xyl4Ac1 and GlcA-Xyl5Ac2) had abnormally high intensities, as well as different tandem mass spectra, than their 4-O-methylated counterparts. These peaks were interestingly enriched in the xylan biosynthesis mutant irx7 and irx9-1. Multi-stages fragmentation analysis using negative ion electrospray-ion trap mass spectrometry indicated that this GlcA was further carrying a pentose residue in the glucuronoxylan-derived oligosaccharide from irx9-1. The structure was also identified in Arabidopsis wild type. The results prove evidence of a new pentose substitution on the GlcA residue of Arabidopsis GX, which is likely present in the primary walls.
authors.affiliation: Department of Food and Environmental Sciences, Faculty of Agriculture and Forestry, University of Helsinki, P.O. Box 27, 00014, Finland. Electronic address: sun-li.chong@helsinki.fi.
authors.forename: Sun-Li
authors.initials: SL
authors.lastname: Chong
authors.affiliation: Department of Food and Environmental Sciences, Faculty of Agriculture and Forestry, University of Helsinki, P.O. Box 27, 00014, Finland.
authors.forename: Sanna
authors.initials: S
authors.lastname: Koutaniemi
authors.affiliation: Department of Food and Environmental Sciences, Faculty of Agriculture and Forestry, University of Helsinki, P.O. Box 27, 00014, Finland.
authors.forename: Minna
authors.initials: M
authors.lastname: Juvonen
authors.affiliation: Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901-83 Umeå, Sweden.
authors.forename: Marta
authors.initials: M
authors.lastname: Derba-Maceluch
authors.affiliation: Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901-83 Umeå, Sweden.
authors.forename: Ewa J
authors.initials: EJ
authors.lastname: Mellerowicz
authors.affiliation: Department of Food and Environmental Sciences, Faculty of Agriculture and Forestry, University of Helsinki, P.O. Box 27, 00014, Finland.
authors.forename: Maija
authors.initials: M
authors.lastname: Tenkanen
mesh_terms: D017360:Arabidopsis / Q000737:chemistry* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics*; D043364:Endo-1,4-beta Xylanases / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D020723:Glucuronic Acid / Q000737:chemistry* / Q000235:genetics; D009844:Oligosaccharides / Q000737:chemistry; D010429:Pentoses / Q000737:chemistry* / Q000235:genetics; D010430:Pentosyltransferases / Q000737:chemistry / Q000235:genetics*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014990:Xylans / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; D009844:Oligosaccharides; D010429:Pentoses; D014990:Xylans; D020723:Glucuronic Acid; C521260:IRX9 protein, Arabidopsis; D010430:Pentosyltransferases; D043364:Endo-1,4-beta Xylanases
keywords: Arabidopsis thaliana; Glucuronoxylan; Tandem mass spectrometry