1. Glucuronic acid in Arabidopsis thaliana xylans carries a novel pentose substituent
- Author
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Minna Juvonen, Sun-Li Chong, Maija Tenkanen, Ewa J. Mellerowicz, Marta Derba-Maceluch, and Sanna Koutaniemi
- Subjects
Pentoses ,Arabidopsis ,Oligosaccharides ,Pentose ,Tandem mass spectrometry ,Mass spectrometry ,Biochemistry ,Glucuronic Acid ,Gene Expression Regulation, Plant ,Structural Biology ,Glucuronoxylan ,Arabidopsis thaliana ,Pentosyltransferases ,Molecular Biology ,chemistry.chemical_classification ,Endo-1,4-beta Xylanases ,biology ,Arabidopsis Proteins ,General Medicine ,Oligosaccharide ,biology.organism_classification ,chemistry ,Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ,Xylans - 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.
- Published
- 2015
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