11 NEWLY CHARACTERIZED XYLOGLUCAN OLIGOGLYCOSYL ALDITOLS - THE SPECIFIC EFFECTS OF SIDE-CHAIN STRUCTURE AND LOCATION ON H-1-NMR CHEMICAL-SHIFTS

Eleven previously uncharacterized oligosaccharides, each containing fr om seventeen to twenty glycosyl residues, were isolated from the xylog lucan produced by suspension-cultured Acer pseudoplatanus cells and ch aracterized by H-1 NMR spectroscopy, fast-atom bombardment mass spectr ometry, and matrix-assisted laser-desorption mass spectrometry. The co mplex mixture of xyloglucan oligosaccharides released by endo-(1-->4)- beta-glucanase (Trichoderma reesei) treatment of cell walls was simila r to that released by digestion of the soluble xyloglucan present in t he culture medium. The oligosaccharides were converted to oligoglycosy l alditols by borohydride reduction and purified by a combination of g el-permeation (Bio-Gel P-2) chromatography, normal-phase HPLC, reverse d-phase HPLC, and high-performance anion-exchange (HPAE) chromatograph y. Eleven new oligoglycosyl alditols (along with several others that h ad been previously characterized) were isolated and characterized, all owing additional correlations between xyloglucan structure and specifi c chemical shift effects in the H-1 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.