NMR characterization of endogenously O-acetylated oligosaccharides isolated from tomato (Lycopersicon esculentum) xyloglucan

摘要: Abstract Eight oligosaccharide subunits, generated by endoglucanase treatment of the plant polysaccharide xyloglucan isolated from culture filtrate suspension-cultured tomato ( Lycopersicon esculentum ) cells, were structurally characterized NMR spectroscopy. These oligosaccharides, which contain up to three endogenous O -acetyl substituents, consist a cellotetraose core with α- d -Xyl p residues at O-6 two β- -Glc non-reducing end core. Some themselves bear either an l -Ara or -Gal residue O-2. -Acetyl substituents are located unbranched (internal) residue, terminal and/or O-5 residue. Structural assignments facilitated long-range scalar coupling interactions observed in high-resolution gCOSY spectra oligosaccharides. The presence five-bond constants provides direct method assigning O-acetylation sites, may prove generally useful analysis O-acylated glycans. Spectral assignment these endogenously O-acetylated oligosaccharides makes it possible deduce correlations between their structural features and chemical shifts diagnostic resonances spectra.