Structural characterisation of xyloglucan secreted by suspension-cultured cells of Nicotiana plumbaginifolia

Carbohydr Res. 1996 Oct 31;293(2):147-72. doi: 10.1016/0008-6215(96)00142-5.

Abstract

Linkage analysis of a xyloglucan from the extracellular medium of suspension cultures of Nicotiana plumbaginifolia showed mostly 4-Glcp and 4,6-Glcp, terminal Xylp and 2-Xylp, and terminal Araf, along with approximately 10% (w/w) O-acetyl groups, equivalent to approximately 0.28 mol acetyl per mol of glycosyl residue. Methylation with methyl trifluoromethanesulfonate under neutral conditions, followed by re-methylation with CD3I under basic conditions, and conversion into partially methylated alditol acetates showed that O-acetyl groups were primarily attached to C-6 of approximately 44% of the 4-Glcp backbone not substituted with Xylp residues and to C-5 of approximately 15% of the terminal Araf residues. These positions of the O-acetyl groups were confirmed by 1H-NMR. Oligosaccharides generated by digestion of native xyloglucan with endo-(1-->4)-beta-glucanase were separated by a combination of gel-filtration chromatography and anion-exchange HPLC, and analysed by glycosyl linkage analysis and by electrospray ionisation-mass spectrometry (ESI-MS). The major oligosaccharide subunits were Glc4Xyl2 and Glc5Xyl2, of which 50-60% are substituted with one terminal Araf residue attached to O-2 of a Xylp residue, and a further 20-25% are substituted with two terminal Araf residues attached to O-2 of the Xylp residues. ESI-MS showed that many of the oligosaccharide subunits carried one, two, and, occasionally three O-acetyl groups.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation
  • Carbohydrate Conformation
  • Carbohydrate Sequence
  • Cell Wall / chemistry
  • Cells, Cultured
  • Chromatography, Gel
  • Chromatography, High Pressure Liquid
  • Chromatography, Ion Exchange
  • Glucans*
  • Glucosidases / metabolism
  • Glycoside Hydrolases / metabolism
  • Magnetic Resonance Spectroscopy
  • Mass Spectrometry
  • Molecular Sequence Data
  • Monosaccharides / analysis
  • Oligosaccharides / analysis
  • Oligosaccharides / chemistry
  • Plants, Toxic*
  • Polysaccharides / chemistry*
  • Polysaccharides / isolation & purification
  • Tobacco / chemistry*
  • Xylans*

Substances

  • Glucans
  • Monosaccharides
  • Oligosaccharides
  • Polysaccharides
  • Xylans
  • xyloglucan
  • Glucosidases
  • Glycoside Hydrolases
  • alpha-N-arabinofuranosidase