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PubMed1998

Alkaline degradation of oligosaccharides coupled with matrix-assisted laser desorption/ionization Fourier transform mass spectrometry: a method for sequencing oligosaccharides.

A new technique for determining sequence and linkage information of underivatized oligosaccharides is developed using alkaline degradation and matrix-assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS). Alkaline degradation (also known as the "peeling" reaction) is a chemical degradation technique that only cleaves the glycosidic bond at the reducing end by beta-elimination to yield a new reducing end. The reaction products are sampled directly with minimal cleanup and monitored by MALDI-FTMS to elucidate the oligosaccharide sequence. Linkage information is provided by cross-ring cleavage fragmentation of the new reducing ends, created by either MALDI source fragmentation or sustained off-resonance irradiation collision-induced dissociation. This method is illustrated by the successful sequence and linkage determination of neutral, branched, fucosylated, and sialylated oligosaccharides. Experiments on differently linked disaccharides are also performed to determine the specificity of the cross-ring cleavage reactions. The power of this technique is enhanced by the Fourier transform mass analyzer, which provides high-resolution, exact mass, and facile tandem mass spectrometry experiments of MALDI-produced ions.

Alkalies↗
PubMed1982

Locations of oligosaccharide chains in human alpha 1-protease inhibitor and oligosaccharide structures at each site.

Previous studies in this laboratory had shown that the alpha 1-protease inhibitor (alpha 1-PI) molecule contained two types of oligosaccharides, biantennary and triantennary. Cleavage of human alpha 1-protease inhibitor with CNBr resulted in three carbohydrate-containing fragments, I-III. Composition data revealed that each of these CNBr fragments contained one oligosaccharide chain. The oligosaccharide structure at each glycosylation site on each purified CNBr fragment was determined by compositional analysis, behavior on Con A affinity chromatography, and methylation analysis. From the results of these studies, we propose that fragment I contains one carbohydrate chain that can be of either the biantennary or triantennary type. On the other hand, fragments II and III each contain one carbohydrate chain exclusively by the biantennary type of complex N-glycoside.

Amino Acids↗
PubMed2003

Simplifying oligosaccharide synthesis: efficient synthesis of lactosamine and siaylated lactosamine oligosaccharide donors.

A practical sequence is described for converting d-glucosamine into peracetylated Gal(beta-1,4)GlcNTroc(beta1-S)Ph and Neu5Ac(alpha-2,3)Gal(beta-1,4)GlcNTroc(beta1-S)Ph building blocks using a synthetic strategy based on chemoenzymatic oligosaccharide synthesis. The known trichloroethoxycarbonyl, N-Troc, protecting group was selected as a suitable protecting group for both enzymatic and chemical reaction conditions. These oligosaccharide building blocks proved effective donors for the beta-selective glycosylation of the unreactive OH-3 of a polymeric PEG-bound acceptor and for the axial OH-2 of a mannose acceptor in good yields. The resulting complex oligosaccharides are useful for vaccine and pharmaceutical applications.

Amino Sugars↗
PubMed2000

Anomeric reactivity-based one-pot oligosaccharide synthesis: a rapid route to oligosaccharide libraries.

The assembly of an oligosaccharide library has been achieved in a practical and efficient manner employing a' one-pot sequential approach. With the help of the anomeric reactivity values of thioglycosides, using a thioglycoside (mono- or disaccharide) with one free hydroxyl group as acceptor and donor coupled with another fully protected thioglycoside, a di- or trisaccharide is selectively formed without self-condensation and subsequently reacted in situ with an anomerically inactive glycoside (mono- or disaccharide) to form a tri- or tetrasaccharide in high overall yield. The approach enables the rapid assembly of 33 linear or branched fully protected oligosaccharides using designed building blocks. These fully protected oligosaccharides have been partially or completely deprotected to create 29 more structures to further increase the diversity of the library.

Carbohydrate Sequence↗
PubMed2003

Comparison of digestibility and breath hydrogen gas excretion of fructo-oligosaccharide, galactosyl-sucrose, and isomalto-oligosaccharide in healthy human subjects.

OBJECTIVES: To clarify the difference of digestibility in the small intestine among fructo-oligosaccharide (FOS), galactosyl-sucrose (GS), and isomalto-oligosaccharide (IMO) using breath hydrogen test. DESIGN: The first step: screening test of breath hydrogen excretion and FOS tolerance test to select the subjects. The second step: breath hydrogen test of three kinds of oligosaccharides, carried out using precautionary regulations. The ingestion order was 10 g of FOS, GS, and IMO, with increases, at 1-week interval, up to 20 g, respectively. Breath gas was collected before, at 20 min intervals from 40 to 120 min after, and at 30 min intervals from 120 min to 7 h after ingestion of test substance. SETTING: Laboratory of Public Health Nutrition, Department of Nutrition and Health Sciences, Siebold University of Nagasaki, Nagasaki, Japan. SUBJECTS: A total of nine males (average: age 25.7+/-3.5 y, weight 61.9+/-8.8 kg, height 170.0+/-6.0 cm) and 29 females (average: 23.1+/-7.2 y, 52.9+/-5.3 kg, 157.5+/-5.1 cm) from the University of Tokyo and Siebold University of Nagasaki. MAIN OUTCOME MEASURES: Breath hydrogen excretion from end-expiratory gas. RESULT: : Breath hydrogen of FOS was more remarkably excreted than that of GS; that of IMO was slight; and that of AUC (10 g) was significantly different. FOS was 9768+/-3253 ppm, GS was 3662+/-2632 ppm, and IMO was 831+/-1154 ppm. A dose dependence was observed at doses between 10 and 20 g of FOS and GS, and the initial time of 20 g was earlier than that of 10 g. CONCLUSIONS: FOS was not hydrolyzed, GS was slightly hydrolyzed, and IMO was readily hydrolyzed by small intestinal enzymes. H(2) gas reflected fermentability in the large intestine. SPONSORSHIP: Siebold University of Nagasaki.

Adult↗
PubMed1972

The oligosaccharide units of rabbit immunoglobulin G. Asymmetric attachment of C2-oligosaccharide.

Two populations of immunoglobulin G (IgG) molecules were isolated from pooled rabbit serum. The first was almost devoid of galactosamine and was obtained in a yield of 7% of the total IgG; the second contained on average a single residue of galactosamine per molecule and was obtained in a yield of 30% of the total IgG. The galactosamine, which is present solely in the C2-oligosaccharide, appeared to be present on one H-chain and not the other in the four-chain structure. Evidence was obtained by the isolation of a glycopeptide linked through a disulphide bridge to a second peptide of the same sequence; the oligosaccharide attached to the first peptide was absent from the complementary peptide. Further evidence was obtained by degradation and analysis of the 5S IgG fragment, which comprises an intact half-molecule coupled through a disulphide bridge to the Fc fragment derived from the opposing half molecule (Goodman, 1965); only the intact H-chain carried the C2-oligosaccharide.

Amino Acid Sequence↗
PubMed1987

Asparagine-linked oligosaccharides of BHK cells treated with inhibitors of oligosaccharide processing.

Baby-hamster kidney (BHK) cells were labelled with [2-3H]mannose for 1-2 days in media containing 1-deoxynojirimycin, N-methyl-1-deoxynojirimycin or 1-deoxymannojirimycin. Glycopeptides obtained by Pronase digestion of disrupted cells were analysed by lectin affinity chromatography, by Bio-Gel P4 gel filtration and by paper chromatography of oligosaccharides released by endo-beta-N-acetylglucosaminidase H. Biosynthesis of complex-type oligosaccharides was diminished but not abolished, the greatest effect being obtained by continuous culture of cells with 1-deoxymannojirimycin. Under these conditions cells contained only 20-30% of the concentration of complex-type chains found in control cells and correspondingly increased amounts of oligomannose-type chains. Similar concentrations of asparagine-linked Man6-GlcNAc2 and Man5GlcNAc2 were present in 1-deoxymannojirimycin-treated cells and control cells, indicating that the inhibition of complex-type chain formation was not related simply to an inability of inhibitor-treated cells to carry out extensive mannosidase-catalysed processing. N-Methyl-1-deoxynojirimycin induced accumulation of oligomannose-type chains containing three glucose residues, and cells treated with 1-deoxynojirimycin contained oligosaccharides with one to three glucose residues. Cells cultured in the presence of the inhibitors retained sensitivity towards the galactose-binding lectins ricin and modeccin.

1-Deoxynojirimycin↗
PubMed2001

Structure of O-glycosidically linked oligosaccharides from glycoproteins of Trypanosoma cruzi CL-Brener strain: evidence for the presence of O-linked sialyl-oligosaccharides.

Glycoproteins on the cell surface of Trypanosoma cruzi are known to play important roles in the interaction of the parasite with the host cells. We previously determined the structures of the O-glycan chains from the sialoglycoproteins (mucin-like molecules) of the G- and Y-strains and observed significant differences between them. We now report the structures of the sialylated and nonsialylated O-linked oligosaccharides isolated from the cell surface glycoproteins of the myotropic CL-Brener strain grown in the presence of fetal calf serum. The structures of the O-linked oligosaccharide alditols obtained by reductive beta-elimination of the sialoglycoprotein were determined by a combination of methylation analysis, fast atom bombardment-mass spectrometry and nuclear magnetic resonance spectroscopy. The presence of a beta-galactopyranose substituent on the N-acetylglucosamine O-4 position shows that these O-linked oligosaccharides from CL-Brener strain belong to the same family as those isolated from mucins expressed by T. cruzi Y strain, a reticulotropic strain. In addition, novel O-glycans, including alpha2-3 mono-sialylated species are described.

Animals↗
PubMed1998

Binding specificities of lectins to immobilized glycoproteins and oligosaccharides differ from those of immobilized lectins to oligosaccharides.

The carbohydrate-binding specificities of lectins in solution to glycoproteins and neoglycolipids immobilized on a solid phase were analyzed in order to establish a simple, rapid method for structural analysis of the carbohydrate moieties of small amounts of individual glycoproteins blotted on membrane. Eight glycoproteins containing typical O-linked tetrasaccharides or a series of typical N-linked oligosaccharides of the high-man-nose type, hybrid type, and complex type and 6 neoglycoproteins containing mono- or di-saccharides were dot blotted on membranes and the membranes were then reacted with 8 kinds of horseradish peroxidase-conjugated lectins before and after heat treatment. Neoglycolipids containing the glycoprotein-derived oligosaccharides immobilized on a thin layer chromatography plate were also reacted with lectins. The heat treatment of the membrane increased lectin reactivity toward the glycoproteins. The carbohydrate-binding behavior of lectins, Phaseolus vulgaris erythroagglutinin, wheat germ agglutinin, and concanavalin A in solution toward glycoproteins and neoglycolipids immobilized on a solid phase differed from that of immobilized lectins toward oligosaccharides in solution. This difference should be noted in lectin detection of specific carbohydrates of individual glycoproteins on membrane.

Glycoproteins↗
PubMed1992

A novel pathway for phosphorylated oligosaccharide biosynthesis. Identification of an oligosaccharide-specific phosphate methyltransferase in dictyostelium discoideum.

The N-linked oligosaccharides on three lysosomal enzymes in Dictyostelium discoideum were found to contain mannose 6-phosphomethyl residues. We have identified and partially characterized a novel S-adenosylmethionine-dependent methyltransferase that is probably responsible for the synthesis of this unusual diester from Man-6-P. The enzyme selectively methylates the phosphate group of Man-6-P (Km 4.3 mM). Glucose-6-P and fructose-1-P are relatively poor acceptors; however, the enzyme is inactive against a broad array of other phosphorylated compounds. Using model di-, tri-, and pentasaccharide acceptors that include portions of the three different branches of high mannose-type oligosaccharides, we found that the enzyme prefers terminal alpha 1----2-linked Man-6-P residues (Km 0.15-1.25 mM) found on the known phosphorylated branches. The enzyme is membrane bound, has a neutral pH optimum and cofractionates on sucrose gradients with GlcNAc-1-P transferase, which resembles its mammalian counterpart, and is, presumably, the first enzyme in the phosphorylation pathway. Based on the substrate specificity and colocalization with GlcNAc-1-P transferase, the phosphate methyltransferase is likely to be responsible for the generation of mannose-6-phosphomethyldiester on Dictyostelium oligosaccharides.

Animals↗
PubMed1995

Lipo-oligosaccharide of Campylobacter lari strain PC 637. Structure of the liberated oligosaccharide and an associated extracellular polysaccharide.

Lipo-oligosaccharide from phenol-water extraction of cells of Campylobacter lari strain PC 637 was separated as a water-insoluble gel of low relative molecular mass (M(r)) from a water-soluble extracellular polysaccharide of high M(r). Structural investigations were performed on the lipo-oligosaccharide and the extracellular polysaccharide, variously using 1H, 13C, and 31P NMR spectroscopy, linkage analysis, and fast atom bombardment-mass spectrometry of permethylated derivatives of the glycans and their products of chemical and enzymic degradation. The following structures are proposed for the highly branched oligosaccharide region: [formula: see text] and for the tetraglycosyl phosphate repeating unit of the extracellular polysaccharide: [formula; see text]

Acetylgalactosamine↗
PubMed1986

Biosynthesis of lipid-linked oligosaccharides in embryonic liver. Glucosylation of mannose containing dolichyl diphosphate oligosaccharide.

A maximum rate of dolichyl phosphate [14C]glucose synthesis from 55-day embryos was achieved at 16 nM concentration of exogenous dolichyl phosphate and exceeded about 3 times that without addition of dolichyl phosphate. The highest values of [14C]glucose incorporation from UDP-[14C]glucose into dolichyl phosphate [14C]glucose, dolichyl diphosphate [14C]Glc-oligosaccharides and protein were reached at 5 min time point of incubation of liver microsomes both from embryos and sows. The radioactive incorporation into proteins was about 7-fold higher in liver microsomes from sows compared to that from embryos, probably due to the greater content of acceptor proteins in microsomes from sows. The enzymatic transfer of Glc3-oligosaccharide from a lipid carrier to endogenous protein acceptor in microsomes from pig embryonic and adult livers was considerably faster than the removal of glucose residues during the initial stages of processing of protein-bound oligosaccharides. One labelled compound was discovered in the CHCl3-CH3OH-H2O (1:1:0.3, by vol) extract after incubation of liver microsomes from embryos and sows with UDP-[14C]glucose. On the basis of its mobility on the chromatogram it appears to be GlcNAc2Man9Glc3.

Animals↗
PubMed1986

The high mannose oligosaccharide of phytohemagglutinin is attached to asparagine 12 and the modified oligosaccharide to asparagine 60.

Phytohemagglutinin, the lectin of the common bean Phaseolus vulgaris, has a high mannose and a modified (fucosylated) oligosaccharide on each polypeptide. Fractionation by high performance liquid chromatography of tryptic digests of [(3)H]fucose or [(3)H]glucosamine labeled phytohemagglutinin, followed by amino acid sequencing of the isolated glycopeptides, shows that the high mannose oligosaccharide is attached to Asn(12) and the modified oligosaccharide to Asn(60) of the protein. In animal glycoproteins, high mannose chains are rarely found at the N-terminal side of complex chains.

Journal Article↗
PubMed1995

The anti-oligosaccharide antibodies present in sera from patients with motor neuron disease and neuropathy recognize the N-glycolylneuraminic acid containing gangliotetrahexosyl oligosaccharide.

We found that serum antibodies present in the serum of patients with motor neuron disease and neuropathy, which were previously shown to react with the oligosaccharide chain of ganglioside GM1(Neu5Ac), can be recognized and titred using the N-glycolylneuraminic acid containing monosialo-gangliotetrahexosylceramide, GM1(Neu5Gc), which is not a component of normal human cells. The antibody-antigen reaction was abolished by immunoabsorption with the free oligosaccharide chain. This result, together with the knowledge that these antibodies recognize several glycoconjugates, supports the conviction that these antibodies are non-specific for a gangliosidic structure.

Animals↗
PubMed1987

Synthesis of oligosaccharide fragments of the repeating unit of Salmonella kentucky O-specific polysaccharide and conversion of the oligosaccharides into the glycosyl phosphates.

alpha-D-Man-(1----2)-alpha-D-Man-(1----3)-D-Gal, a structural fragment of the main chain of Salmonella serogroups C2 and C3 O-specific polysaccharides, and the isomer with the central residue beta have been synthesised, as have some oligosaccharides related to the structure of the O-specific polysaccharide of S. kentucky (serogroup C3), namely, alpha-D-Glc-(1----4)-D-Gal, alpha-D-Man-(1----3)-[alpha-D-Glc-(1----4)]-D-Gal, and alpha-D-Man-(1----2)-alpha-D-Man-(1----3)-[alpha-D-Glc-(1----4)]-D-Gal, and the isomers with the D-Glc unit beta. Each oligosaccharide was converted into the alpha-glycosyl phosphate.

Carbohydrate Conformation↗
PubMed1993

Specificity of mild periodate oxidation of oligosaccharide-alditols: relevance to the analysis of the core-branching pattern of O-linked glycoprotein oligosaccharides.

The specificity of mild periodate oxidation of 3- and 6-substituted 2-acetamido-2-deoxy-D-galactitols and 4- and 6-substituted D-glucitols has been investigated. The products were reacted with 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine and the derivatives were analysed by application of liquid secondary-ion mass spectrometry directly to the TLC plates. There was > 95% specificity of cleavage of the C-4-C-5 bond (threo-diol) for the GalNAcol derivatives. The major sites of oxidation for the Glcol derivatives also involved threo-diols. For alpha-Neu5Ac-(2-->6)-GalNAcol, approximately 30% of the products of oxidation involved the sialic acid side chain, and approximately 60% were cleaved at the C-4-C-5 bond of the GalNAcol moiety. The mild periodate oxidation reaction forms part of a strategy for determining the patterns of branching of the cores of O-linked glycoprotein oligosaccharides and other oligosaccharide-alditols.

Carbohydrate Sequence↗
PubMed1994

Glycamine formation via reductive amination of oligosaccharides with benzylamine: efficient coupling of oligosaccharides to protein.

The conventional reagents for the reductive amination of sugars, ammonium salts or ammonia, require relatively harsh conditions such as high temperatures or high concentrations. In addition, they give substantial amounts of dimeric byproducts. We have developed a method of using benzylamine as a donor to achieve near quantitative amination of reducing oligosaccharides. Benzylamine reacts with reducing oligosaccharides faster and yields less dimeric byproduct than ammonium ion, rendering it especially advantageous for preparative operation. In combination with a heterobifunctional reagent, 5-[N-(2,2-dimethoxyethyl)carbamoyl]pentanoyl azide, [Lee et al. Biochemistry, 28 (1989) 1856-1861], we could couple a nearly maximal number of phosphorylated mannopentaose molecules to ribonuclease A via its primary amino groups.

Acetates↗
PubMed1994

Capillary electrophoretic examination of underivatized O-linked and N-linked oligosaccharide mixtures and immunoglobulin G antibody-released oligosaccharide libraries.

A procedure for the analysis of mixtures of underivatized, cleaved O-linked and N-linked oligosaccharides by capillary electrophoresis has been developed. The species of interest are separated by two borate-based buffer systems with an uncoated capillary. The procedure is applied to hydrazinolysis-released oligosaccharides from mouse, rat, sheep and human IgG protein samples which are examined within 6 minutes. Selectivity with respect to sample variation is demonstrated by analysis of thermally stressed samples.

Animals↗