Typing of core and backbone domains of mucin-type oligosaccharides from human ovarian-cyst glycoproteins by 500-MHz 1H-NMR spectroscopy

Abstract

Human blood‐group A active glycoproteins from ovarian‐cyst fluid were subjected to Smith degradation and subsequent β‐elimination. The resulting oligosaccharide‐alditols represent the core and backbone domains of the O‐linked carbohydrate chains. Nine of these, ranging in size from disaccharides to hexasaccharides, were investigated by 1H‐NMR spectroscopy. Their primary structures could be adequately characterized. In particular, the core types, i.e. the substitution patterns of N‐acetylgalactosaminitol (GalNAc‐ol) as well as the types of backbone, i.e. the linkage types of alternating Gal‐GlcNAc sequences, were unambiguously identified. The core type GlcNAcβ(1–3)GalNAc‐ol is described for the first time as occurring in ovarian‐cyst glycoprotein.

Characterisation by mass spectrometry and 500‐MHz proton nuclear magnetic resonance spectroscopy of penta‐ and hexasaccharide chains of human foetal gastrointestinal mucins (meconium glycoproteins)

“…Signals for the H2, H5 and NAc of GalNAcol, NAc of GlcNAc and H1 of Gal linked to GalNAcol are similar to those reported in the literature for a hexasaccharide of ovarian cyst mucins having the sequences Gal~l-3GlcNAc~l-3Gal/31-4GlcNAc/31-6 and Galpl-linked at C6 and C3 of GalNAcol respectively [21]. The chemical shifts for the tetrasaccharide sequence are also similar to those given for a pentasaccharide lacking the galactose linked at C3 of GalNAcol [25] thus further confirming the assigned structure. In addition, the chemical shifts for H1, H2 and H4 of Gal at 4.442, 3.521 and 3.911 ppm respectively are characteristic of oligosaccharides having a terminal GalPl3GlcNAc sequence [ 191.…”

“…The 'H-NMR chemical shifts for fraction K3(4) shown in Table 8 are similar to those given for an oligosaccharide of human bronchial mucins having the GalPl-4GlcNAcfll-6 and Galfll-4GlcNAcfll-3Galfll-3 sequences [I71 and human ovarian cyst mucins having the Galpl-4GlcNAcfll-6 and Galpl-3GlcNAcfll-3Galfll-3 sequences [25]. There are some differences in chemical shift which are outside the normal variation between laboratories (approximately 0.005 ppm).…”

Primary structure of neutral oligosaccharides derived from respiratory‐mucus glycoproteins of a patient suffering from bronchiectasis, determined by combination of 500‐MHz 1H‐NMR spectroscopy and quantitative sugar analysis

“…By application of empirical rules derived earlier for correlating 'H-NMR features of mucin-type oligosaccharidealditols with their primary structure [2,4,5,7], the identity of nineteen neutral oligosaccharide-alditols that have core type 3 or 4, has been established. The structure determination of oligosaccharide-alditols that possess core type 1 or 2 has been described in the accompanying article [l].…”

Isolation and structural characterization of low‐molecular‐mass monosialyl oligosaccharides derived from respiratory‐mucus glycoproteins of a patient suffering from bronchiectasis

“…All three components could be identified from the NMR spectrum. The main oligosaccharide-alditol present in fraction 9b (denoted 9bl, accounting for 50% of the mixture) was grouped into the core class NeuAcct(2+6)[Ga1~(1+3)JGalNAc-o1, based on the occurrence of the NeuAc H-3ax and H-3eq signals at 6 1 (6 4.480) (compare [13,[25][26][27]), and the position of the GlcNAc3 NAc signal. Combination of the data affords the following structure for pentasaccharide 9bl :…”

“…In combination with the shift effects observed on the H-1 and NAc signals of GlcNAc3 compared to 6b (see Table 7) the 6 H-1 value points to the terminal position of this Gal residue in the chain, and also to its /? (1+4)-linkage to GlcNAc3 [13,25,321. Combination of the data leads to the following structure for 9a3b:…”