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PubMed1993

Monosaccharide and oligosaccharide analysis of proteins transferred to polyvinylidene fluoride membranes after sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

We have developed an intermediate method toward the complete carbohydrate analysis of proteins, which should be universally applicable to all proteins and independent of sample matrix. Using only Coomassie Blue-stained proteins which have been electroblotted onto polyvinylidene fluoride membranes, we report a strategy for: (i) determining unequivocally whether a protein is glycosylated; (ii) obtaining a complete monosaccharide composition; (iii) oligosaccharide mapping which separates most forms according to size, charge and isomerity; and (iv) sequentially releasing and analyzing specific classes of oligosaccharides with endoglycosidases. The method was shown to be applicable to a variety of well characterized soluble glycoproteins and to the membrane-bound protein, the gastric H+, K(+)-ATPase. The monosaccharide composition of the H+,K(+)-ATPase revealed the absence of N-acetylneuraminic or N-glycolylneuraminic acids and a monosaccharide composition which indicated O-linked sugar chains. Oligomannosidic/hybrid and biantennary oligosaccharides were sequentially released and analyzed from one electroblotted band of recombinant tissue plasminogen activator using endo-beta-N-acetylglucosaminidase H and endo-beta-N-acetylglucosaminidase F2, respectively. Sialylated polylactosamine structures were identified and quantified by analyzing high performance liquid chromatography profiles of oligosaccharides first released by peptide-N4-(N-acetyl-beta-D-glucosaminyl)asparagine amidase and then treated with endo-beta-galactosidase, using a single, stained band of recombinant erythropoietin. This recombinant erythropoietin was found to contain eight times more tetrasialylated oligosaccharides than previously reported (Sasaki, H., Bothner, B., Dell, A., and Fukuda, M. (1987) J. Biol. Chem. 262, 12059-12076); 47% of released oligosaccharides were identified as polylactosamine structures.

Animals↗
PubMed1996

Unusual uniformity of the N-linked oligosaccharides of HLA-A, -B, and -C glycoproteins.

MHC class I glycoproteins possess an invariant site for N-linked oligosaccharide addition at position 86 of the heavy chain. For human HLA-A, -B, and -C class I glycoproteins, position 86 is the only site of N-linked glycosylation. Comparison of the size and relative abundance of oligosaccharides associated with nine HLA-A, -B, or -C allotypes isolated from EBV-transformed B cell lines and mixtures of HLA-A, -B, and -C allotypes isolated from pooled PBLs revealed a very restricted set of structures. Allotypes encoded by the HLA-A and -B loci have two predominant glycan structures that were almost exclusively di-sialylated. In contrast, HLA-C allotypes have four glycan structures, comprising those associated with HLA-A and -B and two additional glycans. Identical oligosaccharides were present on different allotypes of a class I HLA locus, and in particular, HLA-C allotypes defining two inhibitory specificities for NK cells were shown to possess the same set of oligosaccharides. The uniformity of oligosaccharide structure associated with different HLA-A, -B, and -C products and the relative lack of heterogeneity for any given allotype are unusual features for a mammalian glycoprotein. Particularly striking is that such conserved oligosaccharide structures juxtapose the major regions of amino acid sequence variation within the Ag recognition site, including the polymorphisms of the alpha 1 helix that determine the inhibitory ligands for human NK cells.

Adult↗
PubMed1977

Reduced synthesis of [14C]mannosyl oligosaccharide-lipid by membranes prepared from concanavalin A-resistant Chinese hamster ovary cells.

We compared the synthesis of mannosyl oligosaccharide-lipid by membranes of wild type and concanavalin A-resistant Chinese hamster ovary cells during incubations with GDP-[14C]mannose and UDP-N-acetylglucosamine. The membranes prepared from exponentially growing mutant cells incorporated 10- to 70-fold less [14C]mannose into oligosaccharide-lipid than did membranes of wild type cells. The lectin-resistant cells are temperature-sensitive for growth. Using temperature-resistant revertants, we showed that the reduction in labeled oligosaccharide-lipid correlated with resistance to concanavalin A rather than with the temperature-sensitive phenotype. Tunicamycin, a specific inhibitor of oligosaccharide-lipid synthesis, reduced the synthesis of the oligosaccharide-lipid by membranes of wild type cells but did not affect the residual synthesis measured in membranes of the mutant cells. As the mutant cells were grown to high density, there was a marked increase in the synthesis of oligosaccharide-lipid by the membranes.

Anti-Bacterial Agents↗
PubMed1997

Heparin-dependent fibroblast growth factor activities: effects of defined heparin oligosaccharides.

Heparin and related molecules have been identified as important participants in fibroblast growth factor (FGF) signaling although the mechanisms of action remain unclear. We have used heparin oligosaccharides to examine steps in the signaling process which could be affected by the polysaccharide. Immobilized FGF-1 and FGF-2 bound all sizes of oligosaccharides tested, ranging from tetrasaccharide to decasaccharide, at physiological salt concentration. Each group of oligosaccharide was eluted from the FGF affinity columns in several peaks, and larger oligosaccharides showed higher apparent affinity for the immobilized growth factors compared to the shorter ones. Heparin hexasaccharides were the smallest fragments providing complete protection of FGF-1 and FGF-2 against trypsin digestion. Tetrasaccharides, however, were able to provide partial protection. The requirement of heparin for ligand-receptor interaction was evaluated in receptor binding assays using Sf9 insect cells engineered to overexpress different recombinant FGF receptor (FGFR) species including FGFR1 beta, FGFR1 alpha or FGFR4 at the cell surface. In these assays hexasaccharides were the smallest fragments capable of stimulating FGF-receptor interaction. Over the range of concentrations examined, neither hexasaccharides nor octasaccharides were able to stimulate receptor binding to the level attained by intact heparin. In fact, these oligosaccharides interfered with the ability of intact heparin in promoting FGF-receptor binding. The presence of both stimulatory and inhibitory activities in hexasaccharide and octasaccharide populations could be attributed to structural heterogeneity within the oligosaccharide preparations. However, similar observations were obtained with "highly-sulfated" structurally homogeneous preparations of hexasaccharide and octasaccharide, although these molecules generally had greater stimulatory and less inhibitory activity than their structurally heterogeneous counterparts. Hexasaccharides were found to be the smallest fragments able to potentiate the FGF-1-induced 3T3 cell proliferation while their effect on FGF-2 signaling was less clear. These observations suggest that heparin can modulate FGF-signaling at several stages with different end results.

3T3 Cells↗
PubMed2006

Mapping of putative quantitative trait loci controlling the total oligosaccharide and sucrose content of Glycine max seeds.

Although oligosaccharides and sucrose are very important nutritional components of soybean seeds, little information is available about inheritance of oligosaccharide and sucrose content. The objective of this study was to identify quantitative trait loci (QTLs) that determine the oligosaccharide and sucrose content of soybean. The 117 F(2:10) recombinant inbred lines developed from a cross of "Keunolkong" and "Shinpaldalkong" were used. Narrow-sense heritability estimates, on a plot mean basis, of oligosaccharide and sucrose content were 79.07 and 74.84%, respectively. Four QTLs for oligosaccharide content were located on linkage groups (LG) C2, H, J, and L. Sucrose content was related with two QTLs located on LG H and J. Total oligosaccharide and sucrose content have two common QTLs on LG H and J.

Chromosome Mapping↗
PubMed1987

Host cell-induced differences in the O-glycosylation of herpes simplex virus gC-1. II. Demonstration of cell-specific galactosyltransferase essential for formation of O-linked oligosaccharides.

By using a lectin-based screening method for cell-dependent variations of O-glycosylation of viral glycoprotein, we found that O-linked oligosaccharides of herpes simplex virus type 1 (HSV-1) glycoproteins in virus-infected mouse neuroblastoma (C1300) cells differed from those of HSV glycoproteins produced in other cells. Thus, O-linked oligosaccharides of HSV-1-specified glycoprotein C (gC-1), produced in GMK cells and a number of other cells, occurred mainly as trisaccharides or larger structures. In contrast, gC-1, produced in C1300 cells, contained O-linked monosaccharides and very few, if any, larger oligosaccharides of this class. A structural comparison between O-linked oligosaccharides of gC-1 from HSV-1-infected C1300 cells and from GMK cells showed that biosynthesis was interrupted prior to formation of a core disaccharide with terminal galactose, indicating a major early defect in O-glycosylation of glycoproteins in C1300 cells. A comparison of the content of galactosyltransferases between C1300 and GMK cells showed that C1300 cells lacked galactosyltransferases, including the specific enzyme engaged in formation of the core O-linked disaccharide mentioned, while other glycosyltransferases adding terminal sugars to O-linked oligosaccharides were present in equal amounts in both cell lines. These results indicated that HSV-1 is strictly dependent on host cell-specified factors for biosynthesis of O-linked oligosaccharides associated with viral glycoproteins.

Animals↗
PubMed2005

Prebiotic effects of oligosaccharides on selected vaginal lactobacilli and pathogenic microorganisms.

The purpose of this study was to select endogenous human vaginal lactobacilli strains on the basis of the main probiotic properties observed in the vaginal environment in order to use them for the evaluation of the potential prebiotic properties of oligosaccharides. From vaginal samples of 50 women with a normal flora, 17 lactobacilli strains were first isolated because of their high level of hydrogen peroxide production. Then six strains were selected mainly for their ability (i) to adhere to vaginal cells, (ii) to produce compounds in sufficient amount, such as lactic acid, having an inhibitory action on pathogens, and less importantly, (iii) to demonstrate arginine deiminase activity. These six strains were found to belong to three distinct species: Lactobacillus crispatus, L. jensenii and L. vaginalis. One strain of each species was chosen as a potential vaginal probiotic strain with regard to our criteria. These three strains were then used to evaluate the prebiotic properties of different oligosaccharide series: two fructooligosaccharide series (FOS Actilight and FOS Raftilose) and two glucooligosaccharide series varying by their osidic linkages (alpha-1,6/alpha-1,4 GOS and alpha-1,2/alpha-1,6/alpha-1,4 GOS). The test was based on the ability of the oligosaccharides to promote the growth of the three beneficial strains selected but not of pathogenic microorganisms often encountered in urogenital infections such as Candida albicans, Escherichia coli and Gardnerella vaginalis. Oligosaccharide hydrolysis was followed by HPLC analysis. This revealed that two oligosaccharide series (FOS Actilight DP3 and all alpha-1,6/alpha-1,4 GOS DP > or = 4) were used only by the lactobacilli strains, the pathogenic microorganisms being unable to metabolise them. The selected lactobacilli and oligosaccharides are good candidates for incorporation in a formula to prevent vaginal infections.

Journal Article↗
PubMed1990

Binding and precipitating activities of Lotus tetragonolobus isolectins with L-fucosyl oligosaccharides. Formation of unique homogeneous cross-linked lattices observed by electron microscopy.

We have recently observed that certain asparagine-linked oligosaccharides are multivalent and capable of binding and precipitating with the D-mannose-specific lectin concanavalin A [cf. Bhattacharyya, L., & Brewer, C. F. (1989) Eur. J. Biochem. 178, 721-726] and with a variety of D-galactose-specific lectins [Bhattacharyya, L., Haraldsson, M., & Brewer, C. F. (1988) Biochemistry 27, 1034-1041]. In the present study, we have examined the binding and precipitating activities of a variety of mono- and biantennary L-fucosyl oligosaccharides with three L-fucose-specific isolectins from Lotus tetragonolobus, LTL-A, LTL-B, and LTL-C. The results show that certain difucosyl biantennary oligosaccharides are capable of cross-linking and precipitating with tetrameric isolectins, LTL-A and LTL-C, but not with dimeric isolectin, LTL-B. Quantitative precipitation analyses show that biantennary oligosaccharides containing the Lewis(x) antigen (or type 2 chain of Lewis(a)), Gal beta (1-4)[Fuc alpha (1-3)]GlcNAc, at the nonreducing terminus of each arm are bivalent ligands. However, a biantennary oligosaccharide containing a Lewis(x) determinant on one arm and a type 2 chain of blood group H(O) determinant, Fuc alpha (1-2)Gal beta (1-4)GlcNAc, on the other arm and a monoantennary oligosaccharide containing two fucose residues (analogue of the Lewis(y) antigen) bind but do not precipitate with the isolectins, indicating that the positions and linkage of fucose residues are critical for cross-linking.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding, Competitive↗
PubMed2000

Characterization of the phosphocholine-substituted oligosaccharide in lipopolysaccharides of type b Haemophilus influenzae.

Haemophilus influenzae expresses heterogeneous populations of short-chain lipopolysaccharide (LPS) which exhibit extensive antigenic diversity among multiple oligosaccharide epitopes. These LPS oligosaccharide epitopes can carry phosphocholine (PCho) substituents, the expression of which is subject to high frequency phase variation mediated by genes in the lic1 genetic locus. The location and site of attachment of PCho substituents were determined by structural analysis of LPS from two type b H. influenzae strains, Eagan and RM7004. The lic2 locus is involved in phase variation of oligosaccharide expression. LPS obtained from the parent strains, from mutants generated by insertion of antibiotic resistance cassettes in the lic2 genetic locus, and from phase-variants showing high levels of PCho expression was characterized by electrospray ionization-mass spectrometry (ESI-MS) and 1H NMR spectroscopy of derived O-deacylated samples. ESI-MS of O-deacylated LPS from wild-type strains revealed mixtures of related glycoform structures differing in the number of hexose residues. Analysis of LPS from PCho-expressing phase-variants revealed similar mixtures of glycoforms, each containing a single PCho substituent. O-Deacylated LPS preparations from the lic2 mutants were much less complex than their respective parent strains, consisting only of Hex3 and/or Hex2 glycoforms, were examined in detail by high-field NMR techniques. It was found that the LPS samples contain the phosphoethanolamine (PEtn) substituted inner-core element, L-alpha-D-Hepp-(1-->2)-[PEtn-->6]-L-alpha-D-Hepp-(1--> 3)-L-alpha-D-He pp-(1-->5)-alpha-Kdo in which the major glycoforms carry a beta-D-Glcp or beta-D-Glcp-(1-->4)-beta-D-Glcp at the O-4 position of the 3-substituted heptose (HepI) and a beta-D-Galp at the O-2 position of the terminal heptose (HepIII). LPS from the lic2 mutants of both type b strains were found to carry PCho groups at the O-6 position of the terminal beta-D-Galp residue attached to HepIII. In the parent strains, the central heptose (HepII) of the LPS inner-core element is also substituted by hexose containing oligosaccharides. The expression of the galabiose epitope in LPS of H. influenzae type b strains has previously been linked to genes comprising the lic2 locus. The present study provides definitive evidence for the role of lic2 genes in initiating chain extension from HepII. From the analysis of core oligosaccharide samples, LPS from the lic2 mutant strain of RM7004 was also found to carry O-acetyl substituents. Mono-, di-, and tri-O-acetylated LPS oligosaccharides were identified. The major O-acetylated glycoforms were found to be substituted at the O-3 position of HepIII. A di-O-acetylated species was characterized which was also substituted at the O-6 postion of the terminal beta-D-Glc in the Hex3 glycoform. This is the first report pointing to the occurrence of O-acetyl groups in the inner-core region of H. influenzae LPS. We have previously shown that in H. influenzae strain Rd, a capsule-deficient type d strain, PCho groups are expressed in a different molecular environment, being attached at the O-6 position of a beta-D-Glcp, which is in turn attached to HepI.

Acetylation↗
PubMed1981

Identification of classical anaphylatoxin as the des-Arg form of the C5a molecule: evidence of a modulator role for the oligosaccharide unit in human des-Arg74-C5a.

A functionally active and potentially lethal fragment of the fifth component of complement (C5) is generated during complement activation in serum from animals of various species. This factor, termed the "classical" anaphylatoxin, was isolated from porcine serum and was identified chemically as the des-Arg derivative of the well-characterized C5a molecule. Unlike the C3a and C4a anaphylatoxins, porcine C5a does not require the COOH-terminal arginyl residue for spasmogenic activity. Further degradation of porcine des-Arg(74)-C5a by carboxypeptidase Y removed glycine-73 and leucine-72 and decreased the intrinsic spasmogenic activity by >90%. Hence, we conclude that, although the arginyl residue is not essential, the COOH-terminal sequence Leu-Gly-Arg contributes structural information that accounts for >90% of C5a activity. Human des-Arg(74)-C5a, like its porcine counterpart, has instrinsic anaphylatoxin activity; however, higher concentrations were needed to contract the guinea pig ileal tissue (i.e., 1 muM for human des-Arg(74)-C5a versus 1 nM for porcine des-Arg(74)-C5a). Furthermore, the des-Arg form of human C5a was only 0.1% as active as porcine des-Arg(74)-C5a for enhancing vascular permeability in guinea pig skin. In addition to these biological differences, numerous chemical differences exist between the human and porcine des-Arg(74)-C5a molecules, the most prominent feature being an oligosaccharide entity associated uniquely with the human C5a. When the oligosaccharide unit of human des-Arg(74)-C5a was removed by glycosidases, leaving a single glucosamine residue attached to the side chain of asparagine-64, activity was enhanced. The human des-Arg(74)-C5a molecule devoid of the complex oligosaccharide unit exhibited 10-fold stronger spasmogenic activity and 20- to 50-fold greater permeability-enhancing activity than did human des-Arg(74)-C5a containing the oligosaccharide. Consequently, the oligosaccharide associated with human C5a modulates or suppresses potentially harmful activities of this anaphylatoxin. The relatively high levels of spasmogenic activity associated with porcine des-Arg(74)-C5a indicate that this factor is poorly controlled by endogenous serum carboxypeptidase, whereas human C5a is virtually inactivated by the enzyme. Hence, the influence of this oligosaccharide in suppressing human des-Arg(74)-C5a activity is of major physiologic importance in protecting man from potentially toxic effects of this complement factor.

Amino Acid Sequence↗
PubMed1984

Glucose removal from N-linked oligosaccharides is required for efficient maturation of certain secretory glycoproteins from the rough endoplasmic reticulum to the Golgi complex.

1- Deoxynojirimycin is a specific inhibitor of glucosidases I and II, the first enzymes that process N-linked oligosaccharides after their transfer to polypeptides in the rough endoplasmic reticulum. In a pulse-chase experiment, 1- deoxynojirimycin greatly reduced the rate of secretion of alpha 1-antitrypsin and alpha 1-antichymotrypsin by human hepatoma HepG2 cells, but had marginal effects on secretion of the glycoproteins C3 and transferrin, or of albumin. As judged by equilibrium gradient centrifugation, 1- deoxynojirimycin caused alpha 1-antitrypsin and alpha 1-antichymotrypsin to accumulate in the rough endoplasmic reticulum. The oligosaccharides on cell-associated alpha 1-antitrypsin and alpha 1-antichymotrypsin synthesized in the presence of 1- deoxynojirimycin , remained sensitive to Endoglycosidase H and most likely had the structure Glu1- 3Man9GlcNAc2 . Tunicamycin, an antibiotic that inhibits addition of N-linked oligosaccharide units to glycoproteins, had a similar differential effect on secretion of these proteins. Swainsonine , an inhibitor of the Golgi enzyme alpha-mannosidase II, had no effect on the rates of protein secretion, although the proteins were in this case secreted with an abnormal N-linked, partially complex, oligosaccharide. We conclude that the movement of alpha 1-antitrypsin and alpha 1-antichymotrypsin from the rough endoplasmic reticulum to the Golgi requires that the N-linked oligosaccharides be processed to at least the Man9GlcNAc2 form; possibly this oligosaccharide forms part of the recognition site of a transport receptor for certain secretory proteins.

1-Deoxynojirimycin↗
PubMed2004

Preparation and application of biologically active fluorescent hyaluronan oligosaccharides.

We report the production of biologically active hyaluronan (HA) oligosaccharides labeled with the fluorophore 2-aminobenzoic acid (2AA). Oligosaccharides from 4 to 40 residues in length were purified to homogeneity by ion exchange chromatography using a logarithmic gradient. Molecular weight and purity characterization of HA oligosaccharides is facilitated by 2AA derivatization because it enhances signals in MALDI-TOF MS and improves FACE (fluorophore-assisted carbohydrate electrophoresis) analysis by avoiding the inverted parabolic migration characteristic of 2-aminoacridone (AMAC)-labeled sugars. The small size and shape of the fluorophore maintains the biological activity of the derivatized oligosaccharides, as demonstrated by their ability to compete for polymeric HA binding to the G1-domain of human recombinant versican (VG1). An electrophoretic mobility shift assay was used to study VG1 binding to labeled HA 8-, 10-, 20-, 30-, and 40-mers, and although no stable VG1 binding was observed to labeled 8-mers, the equilibrium dissociation constant (100 nM) for VG1 with HA(10) was estimated from densitometry analysis of the free oligosaccharide. Interactions involving HA 20-, 30-, and 40-mers (proposed to be multivalent) could also be studied using this protocol. Oligosaccharides labeled with 2AA therefore show excellent potential as probes in fluorescence-based assays that investigate protein-carbohydrate interactions.

Animals↗
PubMed2004

Xyloglucan oligosaccharides cause cell wall loosening by enhancing xyloglucan endotransglucosylase/hydrolase activity in azuki bean epicotyls.

Addition of xyloglucan-derived oligosaccharides shifted the wall-bound xyloglucans to a lower molecular mass distribution and increased the cell wall extensibility of the native epidermal tissue strips isolated from azuki bean (Vigna angularis) epicotyls. To ascertain the mechanism of oligosaccharide function, we examined the action of a xyloglucan endotransglucosylase/hydrolase (XTH) showing both endotransglucosylase and endohydrolase activities, isolated from azuki bean epicotyl cell walls, in the presence of xyloglucan oligosaccharides. The addition of xyloglucan oligosaccharides enhanced the xyloglucan-degrading activity of XTH against isolated xyloglucan substrates. When the methanol-fixed epidermal tissue strips were incubated with XTH, the molecular mass of wall-bound xyloglucans was decreased and the cell wall extensibility increased markedly in the presence of the oligosaccharides. These results suggest that xyloglucan oligosaccharides stimulate the degradation of xyloglucans by enhancing the XTH activity within the cell wall architecture, thereby increasing the cell wall extensibility in azuki bean epicotyls.

Cell Wall↗
PubMed1996

Pentavalent pneumococcal oligosaccharide conjugate vaccine PncCRM is well-tolerated and able to induce an antibody response in infants.

BACKGROUND: The emergence of resistant pneumococci makes the treatment of pneumococcal diseases difficult. The currently available polysaccharide vaccines have very limited efficacy in young children. The immunogenicity can be improved by covalent coupling to protein carriers as has been shown with Haemophilus influenzae type b. METHODS: Thirty healthy infants were immunized with a pneumococcal conjugate vaccine at 2, 4 and 6 months of age. Oligosaccharides were derived from capsular polysaccharides of types 6B, 14, 18C, 19F and 23F and conjugated to the nontoxic mutant diphtheria toxin CRM197. The final vaccine was a mixture of these conjugates, containing 10 micrograms of each oligosaccharide. The infants received simultaneously H. influenzae type b oligosaccharide-CRM197 conjugate vaccine. Serum samples were taken before each dose and 1 month after the third dose. Control material was composed of 25 serum samples taken from children of the same age without pneumococcal vaccination. Enzyme-linked immunosorbent assay was used to measure serum IgG anti-pneumococcal polysaccharide concentrations and radioimmunoassay for the serum Ig anti-H. influenzae type b concentrations. RESULTS: PncCRM vaccine was well-tolerated. Pneumococcal type 18C induced a significant antibody increase after the first dose, whereas the other five oligosaccharides, including H. influenzae type b oligosaccharides, induced an increase after the second or third dose. The specific IgG concentrations at 7 months of age were significantly higher among the vaccinated infants than in the controls for all the five pneumococcal types. CONCLUSIONS: Pneumococcal oligosaccharide-CRM197 conjugate vaccine is able to induce an IgG serum response in infants and anti-pneumococcal antibody concentrations were significantly higher than in controls of same age.

Antibodies, Bacterial↗
PubMed1981

Transfer of oligosaccharide to protein from a lipid intermediate in plants.

A lipid-bound oligosaccharide was isolated from pea (Pisum sativum) cotyledons incubated with [(14)C]mannose. The oligosaccharide moiety appeared to be identical with the one obtained from rat liver, known to contain three glucoses, nine mannoses, and two N-acetylglucosamines, and to be involved in protein glycosylation.Enzymes obtained from soya (Glycine max) roots and developing pea cotyledons were found to catalyze the transfer of oligosaccharide from the lipid intermediate to endogenous protein. The enzymes require Mn(2+) and detergent for activity. Evidence is presented indicating that the lipid-bound oligosaccharide with three glucoses is transferred faster than that with less. Some of the peripheral mannoses could be removed without affecting the rate of transfer.The protein-bound oligosaccharide, formed by incubation of whole cotyledons or by transfer with the enzyme preparation, could be released by protease and endo-beta-N-acetylglucosaminidase treatment, as expected for an asparagine-bound high mannose oligosaccharide.

Journal Article↗
PubMed1996

Sequence Analysis of the Oligosaccharides from Scarlet Runner Bean Lectin.

Two oligosaccharide chains from scarlet runner bean (Phaseolus coccineus var. rubronanus) lectin (PCL) were obtained by hydrazinolysis, Bio-Gel P-2 column chromatography, NaBH(4) reduction and then separated on a Bio-Gel P-2 column. The oligosaccharides were methanolysed, acetylysed and then transformed into derivatives of trimethylsilane. Gas chromatographic studies of these two derivatives showed that their compositions were: Man(8)XylGlcNAc(2) (oligosaccharide I) and Man(6)XylGlcNAc(2)Fuc (oligosaccharide II). The size of these two oligosaccharides after digestion by alpha-mannosidase, beta-xylosidase and alpha-fucosidase separately, were determined on a standardized Bio-Gel P-4 column. Thus the sequences of these two oligosaccharides were celucidated as: (Manalpha)(7)ManBetaXylBeta(GlcNAc)(2) and (Manalpha)(5)ManbetaXylbeta(GlcNAc)(2)Fucalpha.

Journal Article↗
PubMed1985

Formation of lipid-linked oligosaccharides by MOPC 315 plasmacytoma cells. Decreased synthesis by a nonsecretory variant.

MOPC 315 is a BALB/c plasmacytoma which secretes a trinitrophenol-binding IgA lambda 2 paraprotein. We have investigated the incorporation of [3H]mannose into lipid-linked oligosaccharide precursors in wild-type MOPC 315/J and variant nonsecretory 315/P cells. In pulse labeling experiments, no differences could be detected in the ability of the two cell types to incorporate [3H]mannose into lipid-linked oligosaccharides containing 5 or less mannose residues. In contrast, quantitation of the incorporation of [3H]mannose into larger lipid-linked oligosaccharides and proteins revealed a 49 and 40% decrease, respectively, in the 315/P cells compared to wild-type cells. Further characterization of the lipid-linked structures documented a marked decrease in glucosylated oligosaccharides isolated from 315/P cells. When membranes from the two cell lines were analyzed for their ability to transfer [3H]glucose from UDP-[3H]glucose to [3H]glucosylphosphoryldolichol, an apparent deficiency was noted in the 315/P preparations. However, if assay conditions were adjusted to include AMP in the reaction mixtures, no differences in the in vitro synthesis of [3H]glucosylphosphoryldolichol or [3H]glucose-labeled oligosaccharide-lipid could be detected. In these reactions AMP was found to prevent hydrolysis of UDP-[3H]glucose by inhibiting nucleotide pyrophosphatase (EC 3.6.1.9), the specific activity of which was determined to be more than 100 times greater in variant 315/P compared to wild-type MOPC 315/J cells. This large difference in specific activity was not accompanied by similar differences in the activity of several other enzymes analyzed. A decrease in whole cell UDP-glucose pool size was not detected in 315/P cells. Therefore, if nucleotide pyrophosphatase is important for the control of substrates for glycosylation, it must regulate nucleotide sugar levels at a site other than the cytoplasm of cells, perhaps at the location of synthesis of the larger lipid-linked oligosaccharides.

Animals↗
PubMed1982

Newcastle disease virus contains a linkage-specific glycoprotein sialidase. Application to the localization of sialic acid residues in N-linked oligosaccharides of alpha 1-acid glycoprotein.

Newcastle disease virus sialidase was found to exhibit strict specificity for hydrolysis of the NeuAc alpha 2 leads to 3Gal linkage contained in glycoprotein oligosaccharides both N-linked to asparagine and O-linked to threonine or serine under conditions that left oligosaccharides containing the NeuAc alpha 2 leads to 2 leads to 6Gal and NeuAc alpha 2 leads to 6GallNAc linkages intact. This was determined, in part, by examining the viral sialidase for its ability to hydrolyze glycoprotein oligosaccharides derivatized with purified sialyltransferases to contain the [14C]NeuAc alpha 2 leads to 3Gal, [14C]NeuAc alpha 2 leads to 6GalNAc, and [14C]NeuAc alpha 2 leads to 6Gal linkages. The viral sialidase was also tested for hydrolysis of the NeuAc alpha 2 leads to 3Gal and NeuAc alpha 2 leads to 6Gal linkages on the N-linked oligosaccharides of alpha 1-acid glycoprotein. Selective hydrolysis of the NeuAc alpha 2 leads to 3Gal linkage was shown by periodate oxidation and by 500-MHz 1H-NMR spectroscopy of native and sialidase-treated glycopeptides. The NMR spectra, together with composition data, further indicated that the NeuAc alpha 2 leads to 3Gal and NeuAc alpha 2 leads to 6Gal linkages were localized to specific branches of the major tri- and tetraantennary oligosaccharides of alpha 1-acid glycoprotein. The results indicate that the Newcastle disease virus sialidase can initiate the selective degradation of N-linked oligosaccharide branches containing the NeuAc alpha 2 leads to 3Gal linkage.

Carbohydrate Conformation↗