Eleven newly characterized xyloglucan oligoglycosyl alditols: the specific effects of sidechain structure and location on 1H NMR chemical shifts

Eleven previously uncharacterized oligosaccharides, each containing from seventeen to twenty glycosyl residues, were isolated from the xyloglucan produced by suspension-cultured Acer pseudoplatanus cells and characterized by 1H NMR spectroscopy, fast-atom bombardment mass spectrometry, and matrix-assisted laser-desorption mass spectrometry. The complex mixture of xyloglucan oligosaccharides released by endo-(1 → 4)-β-glucanase (Trichoderma reesei) treatment of cell walls was similar to that released by digestion of the soluble xyloglucan present in the culture medium. The oligosaccharides were converted to oligoglycosyl alditols by borohydride reduction and purified by a combination of gel-permeation (Bio-Gel P-2) chromatography, normal-phase HPLC, reversed-phase HPLC, and high-performance anion-exchange (HPAE) chromatography. Eleven new oligoglycosyl alditols (along with several others that had been previously characterized) were isolated and characterized, allowing additional correlations between xyloglucan structure and specific chemical shift effects in the 1H NMR spectra to be determined. The correlations between structural and spectral features deduced in this study will facilitate the structural determination of a wide range of xyloglucans and their subunit oligosaccharides.