Glucuronic acid in Arabidopsis thaliana xylans carries a novel pentose substituent

Int J Biol Macromol. 2015 Aug:79:807-12. doi: 10.1016/j.ijbiomac.2015.05.056. Epub 2015 Jun 3.

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.

Keywords: Arabidopsis thaliana; Glucuronoxylan; Tandem mass spectrometry.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / chemistry*
  • Arabidopsis / genetics
  • Arabidopsis Proteins / chemistry
  • Arabidopsis Proteins / genetics*
  • Endo-1,4-beta Xylanases / genetics
  • Gene Expression Regulation, Plant
  • Glucuronic Acid / chemistry*
  • Glucuronic Acid / genetics
  • Oligosaccharides / chemistry
  • Pentoses / chemistry*
  • Pentoses / genetics
  • Pentosyltransferases / chemistry
  • Pentosyltransferases / genetics*
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Xylans / biosynthesis
  • Xylans / chemistry
  • Xylans / genetics*

Substances

  • Arabidopsis Proteins
  • Oligosaccharides
  • Pentoses
  • Xylans
  • Glucuronic Acid
  • IRX9 protein, Arabidopsis
  • Pentosyltransferases
  • Endo-1,4-beta Xylanases