tailieunhanh - Báo cáo khóa học: Determination by electrospray mass spectrometry and 1H-NMR spectroscopy of primary structures of variously fucosylated neutral oligosaccharides based on the iso-lacto-N-octaose core

We have isolated a nonfucosylated and three variously fucosylated neutral oligosaccharides from human milk that are based on theiso-lacto-N-octaose core. Their structures were characterized by the combined use of electrospray mass spectrometry (ES-MS) and NMR spectroscopy. The branching pattern and blood group-related Lewis deter-minants, together with partial sequences and linkages of these oligosaccharides, were initially elucidated by high-sensitivity ES-MS/MS analysis, and then their full structure assignment was completed by methylation analysis and 1 H-NMR. Three new structures were identified | Eur. J. Biochem. 271 1172-1186 2004 FEBS 2004 doi Determination by electrospray mass spectrometry and 1H-NMR spectroscopy of primary structures of variously fucosylated neutral oligosaccharides based on the sơ-lacto- -octaose core Heide Kogelberg1 Vladimir E. Piskarev2 Yibing Zhang1 Alexander M. Lawson1 and Wengang Chai1 1MRC Glycosciences Laboratory Imperial College Faculty of Medicine Northwick Park Institute for Medical Research Harrow Middlesex UK 2Nesmeyanov Institute of Organoelement Compounds Russian Academy of Sciences Moscow Russia We have isolated a nonfucosylated and three variously fucosylated neutral oligosaccharides from human milk that are based on the iso-lacto-N-octaose core. Their structures were characterized by the combined use of electrospray mass spectrometry ES-MS and NMR spectroscopy. The branching pattern and blood group-related Lewis determinants together with partial sequences and linkages of these oligosaccharides were initially elucidated by high-sensitivity ES-MS MS analysis and then their full structure assignment was completed by methylation analysis and 1H-NMR. Three new structures were identified. The nonfucosylated iso-lacto-N-octaose Galp1-3GlcNAcp1- 3Galp--4GlcNAcP--6 Galp--3GlcNAcP--3 Galp--4Glc has not previously been reported as an individual oligosaccharide. The monofucosylated and trifucosylated zso-lacto-N-octaose Galp--3GlcNAcP--3Galp--4 Fuca--3 GlcNAcP--6 Galp--3GlcNAcP--3 Galp--4Glc and Galp1- 3 Fuca1-4 GlcNAcp1-3Galp1-4 Fuca1-3 GlcNAcp1-6 Galp1-3 Fuca1-4 GlcNAcp 1-3 Galp1-4Glc both containing an internal Lex epitope are also novel structures. Keywords electrospray mass spectrometry human milk oligosaccharide NMR. A role for carbohydrates in cellular events has long been hypothesized although strong evidence for this has only emerged over the last two decades. Awareness of the biological function of oligosaccharide chains in glycoproteins glycolipids and proteoglycans has intensified as