Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “OLIGOSACCHARIDES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,171 records · Page 65Linked to original sources
PubMed1990

Isolation of glycopeptides containing O-linked oligosaccharides by lectin affinity chromatography on jacalin-agarose.

Jacalin is a lectin which has high specificity and affinity for the core disaccharide, 1-beta-galactopyranosyl-3-(alpha-2-acetamido-2-deoxygalactopyranoside ), in O-linked oligosaccharides. Here, it is shown that this lectin can be used for isolation of glycopeptides bearing O-linked oligosaccharides. Peptides produced by digestion of reduced and carboxamidomethylated human plasminogen or of bovine protein Z were chromatographed on a column of jacalin-agarose. Reverse-phase high-performance liquid chromatography revealed that two peptides from plasminogen and one from protein Z were eluted from the jacalin-agarose column by alpha-methylgalactopyranoside. Amino acid sequence and compositional analysis showed that both of the peptides from plasminogen consisted of residues 330-357 and that the single peptide from protein Z represented residues 385-396. These sequences contain the single known site of attachment of O-linked oligosaccharides to these proteins. The present analysis suggested that there may be a fraction of plasminogen with two sites of O-linked glycosylation. The two tryptic peptides isolated from plasminogen represented the same segment of the protein but sequence analysis showed that one peptide was modified only at Thr346, the known site of glycosylation, and the other peptide contained a modification of Ser339 as well. Results of the present study indicate that lectin affinity chromatography using jacalin-agarose can be a useful technique for isolating glycopeptides containing O-linked oligosaccharides and thereby localizing sites of attachment of these oligosaccharides.

Amino Acid Sequence↗
PubMed1992

Directed enzymatic synthesis of linear and branched gluco-oligosaccharides, using cyclodextrin-glucanosyltransferase.

Cyclodextrin-glucanosyltransferase, in a kinetically controlled reaction, transfers one maltohexaosyl residue from cyclomaltohexaose (alpha CD) to HO-4 of an acceptor to form a linear or a branched gluco-oligosaccharide. The primary transfer product can be isolated in yields up to 45% and in high purity, if the reaction is stopped at an early stage. With increasing time of incubation, secondary and tertiary transfer products are formed by stepwise addition of maltohexaosyl units. At equilibrium, a mixture with almost equal proportions of oligosaccharides is obtained. Glucose and malto-oligosaccharides of any chain length carrying a free 4-hydroxyl group and with HO-1 free or substituted, and regardless of the configuration at C-1, may serve as acceptors. Substrates with galacto or manno configuration were not utilised by the enzyme. The selectivity of the enzyme with respect to the site of chain elongation in branched acceptor molecules has been investigated. The technique described here may be applied to prepare linear gluco-oligosaccharides of any chain length of branched oligosaccharides of the amylopectin type.

Bacillus↗
PubMed1991

Diabetic BB/Wor rat haptoglobin exhibits a probable structural abnormality in Asn-linked oligosaccharides.

In this study we demonstrate that haptoglobin, a serum glycoprotein secreted by the liver, has altered structure in the BB/Wor diabetic rat. SDS-PAGE of haptoglobin (a tetramer composed of two glycosylated beta-chains each containing two sites for Asn-linked oligosaccharides connected by disulfide bonds with two nonglycosylated alpha-chains) clearly shows that the beta-chain of haptoglobin from diabetic rats is smaller than normal, with a molecular mass of 39 instead of 40 kDa. Both acute and chronic diabetic rats exhibit the defect. Defective haptoglobin appears in the serum within 4 days of onset of the disease, but insulin therapy prevents the defect. Removal of Asn-linked oligosaccharides with peptide: N-glycosidase F from Flavobacterium meningosepticum abolished the size difference between the beta-chains from normal and diabetic haptoglobin, with the molecular mass in both cases shifting to 30 kDa. Haptoglobin from both normal and diabetic rats was resistant to digestion by endoglycosidase H from Streptomyces griseus, which cleaves high mannose-type chains. Removal of sialic acid with neuraminidase treatment resulted in a reduction in the molecular mass in both cases, but without eliminating the size difference between the two. These results demonstrate that haptoglobin from diabetic BB/Wor rats contains a structural abnormality which correlates with onset of the disease. The defect is most likely due to an alteration in Asn-linked oligosaccharides, probably involving a change in the neutral sugars of complex-type oligosaccharide chains. This finding represents the first example of an altered Asn-linked oligosaccharides in diabetes.

Animals↗
PubMed2005

Feruloyl oligosaccharides stimulate the growth of Bifidobacterium bifidum.

Insoluble dietary fiber from wheat bran contains some feruloyl groups linked to the arabinose residues in the cell wall arabinoxylan. Treatment of wheat bran insoluble dietary fiber with xylanase from Bacillus subtilis yielded feruloyl oligosacchairdes, which were purified with Amberlite XAD-2. Saponification of the feruloyl oligosaccharides released ferulic acid and arabinoxylan oligosaccharides which consist of arabinose and xylose. The effect of the feruloyl oligosacchairdes on the growth of Bifidobacterium bifidum F-35 was investigated in vitro. The B. bifidum produced acid when cultivated anaerobically in TPY broth with 0.5% feruloyl oligosacchairdes as the carbohydrate source. The biomass yield of the B. bifidum increased with increasing the concentration of feruloyl oligosaccharides in TPY broth. The maximum cell growth was increased by 50% in TPY broth supplemented with 0.1% feruloyl oligosaccharides compared to TPY broth. These results indicated that the growth of B. bifidum F-35 was promoted by the feruloyl oligosaccharides from wheat bran insoluble dietary fiber, and not suppressed by the ferulic acid moiety of them.

Journal Article↗
PubMed1997

Analysis of 1-aminopyrene-3,6,8-trisulfonate-derivatized oligosaccharides by capillary electrophoresis with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), has been used for structure characterization of 1-aminopyrene-3,6,8-trisulfonate (APTS)-derivatized oligosaccharides previously separated by capillary electrophoresis (CE). The resolved components were first isolated by employing an automated high-resolution fraction collector. Using on-probe sample cleanup with a cation-exchange resin and a matrix mixture of (1:1) 6-hydroxypicolinic acid and 3-hydroxypicolinic acid, APTS-labeled oligosaccharides were successfully detected by MALDI-TOF MS in the negative ionization mode. Each APTS-labeled oligosaccharide produced single [M-H]-1 peaks. Detection limits for standard APTS-derivatized oligosaccharide (maltoheptaose) were down to 30 fmol. APTS labeled maltooligosaccharides and various standard carbohydrates were separated and collected by CE, followed by molecular weight determination with MALDI-TOF MS. The mass spectral characterization enhances the power of the CE analysis of oligosaccharides.

Carbohydrate Sequence↗
PubMed2000

Fermentation of plant cell wall derived polysaccharides and their corresponding oligosaccharides by intestinal bacteria.

New types of nondigestible oligosaccharides were produced from plant cell wall polysaccharides, and the fermentation of these oligosaccharides and their parental polysaccharides by relevant individual intestinal species of bacteria was studied. Oligosaccharides were produced from soy arabinogalactan, sugar beet arabinan, wheat flour arabinoxylan, polygalacturonan, and rhamnogalacturonan fraction from apple. All of the tested substrates were fermented to some extent by one or more of the individual species of bacteria tested. Bacteroides spp. are able to utilize plant cell wall derived oligosaccharides besides their reported activity toward plant polysaccharides. Bifidobacterium spp. are also able to utilize the rather complex plant cell wall derived oligosaccharides in addition to the bifidogenic fructooligosaccharides. Clostridium spp., Klebsiella spp., and Escherichia coli fermented some of the selected substrates in vitro. These studies do not allow prediction of the fermentation in vivo but give valuable information on the fermentative capability of the tested intestinal strains.

Bacteria↗
PubMed2001

Combined strong anion-exchange HPLC and PAGE approach for the purification of heparan sulphate oligosaccharides.

Heparan sulphates are highly sulphated linear polysaccharides involved in many cellular functions. Their biological properties stem from their ability to interact with a wide range of proteins. An increasing number of studies, using heparan sulphate-derived oligosaccharides, suggest that specific structural features within the polysaccharide are responsible for ligand recognition and regulation. In the present study, we show that strong anion-exchange HPLC alone, a commonly used technique for purification of heparan sulphate-derived oligosaccharides, may not permit the isolation of highly pure heparan sulphate oligosaccharide species. This was determined by PAGE analysis of hexa-, octa- and decasaccharide samples deemed to be pure by strong anion-exchange HPLC. In addition, subtle differences in the positioning of sulphate groups within heparan sulphate hexasaccharides were impossible to detect by strong anion-exchange HPLC. PAGE analysis on the other hand afforded excellent resolution of these structural isomers. The precise positioning of specific sulphate groups has been implicated in determining the specificity of heparan sulphate interactions and biological activities; hence, the purification of oligosaccharide species that differ in this way becomes an important issue. In this study, we have used strong anion-exchange HPLC and PAGE techniques to allow production of the homogeneous heparan sulphate oligosaccharide species that will be required for the detailed study of structure/activity relationships.

Animals↗
PubMed1969

Structural studies on colanic acid, the common exopolysaccharide found in the enterobacteriaceae, by partial acid hydrolysis. Oligosaccharides from colanic acid.

The exopolysaccharide slime colanic acid has been isolated from representative strains of Escherichia coli, Salmonella typhimurium and Aerobacter cloacae. Analysis showed that each polymer contained glucose, galactose, fucose and glucuronic acid, together with acetate and pyruvate. The molar proportions of these components were 1:1.8:1.9:1:1:1 approximately. On the basis of periodate oxidation of the natural and deacetylated polysaccharide, glucose is proposed as the site of the acetyl groups. The pyruvate is attached to galactose. Three neutral oligosaccharides and ten electrophoretically mobile oligosaccharides were isolated and partially characterized. Four of the fragments were esters of pyruvic acid. Most oligosaccharides were isolated from all three polysaccharide preparations. Three further oligosaccharides were isolated from carboxyl-reduced colanic acid and sodium borotritide was used to label the glucose derived from glucuronic acid in these fragments. One trisaccharide was obtained from periodate-oxidized polysaccharide. On the basis of these oligosaccharides a repeating hexasaccharide unit of the following structure is proposed: [Formula: see text] The significance of this structure in colanic acid biosynthesis is discussed.

Acetates↗
PubMed1983

Effects of bleomycin and methylprednisolone on the biosynthesis of oligosaccharide-lipids and glycoproteins in lung.

Tissues from rabbit lung were found to incorporate radioactivity from [3H]mannose into the oligosaccharide of a polar lipid soluble in chloroform/methanol/water (10:10:3, by vol.). Only one oligosaccharide-lipid was formed and the composition of the radiolabelled carbohydrate moiety was Glc3Man9(GlcNAc)2. An antitumour antibiotic, bleomycin, and an anti-inflammatory steroid, methylprednisolone, partially inhibited the incorporation of [3H]mannose into oligosaccharide-lipids and in addition resulted in the production of two new components, Man5(GlcNAc)2 and Man2(GlcNAc)2. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of the glycoproteins synthesized from the oligosaccharide-lipid intermediates showed labelled components with Mr greater than 200000, 130000, 80000 and 62000. The addition of the drugs resulted in the same pattern with the addition of a new component of Mr 36000. Endoglucosaminidase H-treatment of the glycopeptides isolated from the Pronase-digested glycoproteins indicated that the oligosaccharide units in the glycoproteins were of the high-mannose-type.

Animals↗
PubMed1998

Auxin transport inhibition precedes root nodule formation in white clover roots and is regulated by flavonoids and derivatives of chitin oligosaccharides.

The expression of the auxin responsive reporter construct, GH3:gusA, was examined in transgenic white clover plants to assess changes in the auxin balance during the earliest stages of root nodule formation. Reporter gene expression was monitored at marked locations after the application of bacteria or signal molecules using two precise inoculation techniques: spot-inoculation and a novel method for ballistic microtargeting. Changes in GH3:gusA expression were monitored after the inoculation of Rhizobium leguminosarum biovar trifolii, non-host rhizobia, lipo-chitin oligosaccharides (LCOs), chitin oligosaccharides, a synthetic auxin transport inhibitor (naphthylphthalamic acid; NPA), auxin, the ENOD40-1 peptide or different flavonoids. The results show that clover-nodulating rhizobia induce a rapid, transient and local downregulation of GH3:gusA expression during nodule initiation followed by an upregulation of reporter gene expression at the site of nodule initiation. Microtargeting of auxin caused a local and acropetal upregulation of GH3:gusA expression, whereas NPA caused local and acropetal downregulation of expression. Both spot-inoculation and microtargeting of R. l. bv. trifolii LCOs or flavonoid aglycones induced similar changes to GH3:gusA expression as NPA. O-acetylated chitin oligosaccharides caused similar changes to GH3:gusA expression as R. l. bv. trifolii spot-inoculation, but only after delivery by microtargeting. Non-O-acetylated chitin oligosaccharides, flavonoid glucosides or the ENOD40-1 peptide failed to induce any detectable changes in GH3:gusA expression. GH3:gusA expression patterns during the later stages of nodule and lateral root development were similar. These results support the hypothesis that LCOs and chitin oligosaccharides act by perturbing the auxin flow in the root during the earliest stages of nodule formation, and that endogenous flavonoids could mediate this response.

Journal Article↗
PubMed1980

Oligosaccharide moieties of glycoprotein hormones: bovine lutropin resists enzymatic deglycosylation because of terminal O-sulfated N-acetylhexosamines.

The oligosaccharides of the bovine pituitary gonadotropin lutropin are N-linked to asparagine residues. These carbohydrates are unusual in that, although they contain the mannose, N-acetylglucosamine, and fucose typical of N-linked oligosaccharides, they also contain one residue of N-acetylgalactosamine but insignificant amounts of sialic acid or galactose. These oligosaccharides exhibit complete resistance to several exoglycosidases. This is in contrast to the ready release of peripheral sugars from human chorionic gonadotropin, a placenta hormone which has oligosaccharides of the complex type with terminal sialic acid and galactose residues. Stability of the lutropin hexosamines to periodate oxidation and reduction (Smith degradation) together with other data show that one residue of N-acetylgalactosamine and one of N-acetylglucosamine are peripheral to two periodate-sensitive mannose residues. The insensitivity to periodate of these two terminal amino sugars is found to result from a sulfate group covalently linked to each; sulfation of these hexosamines is also the most probable reason for the resistance to enzymatic deglycosylation. The alpha subunits of bovine thyrotropin and human pituitary lutropin also contain sulfate, in contrast to human chorionic gonadotropin. The results indicate that sulfating enzymes are present in the pituitary and that sulfation of peripheral sialic acids in the placental gonadotropin. The data lead to a partial structure for the oligosaccharides of bovine LH as follows: (formula see text).

Acetylgalactosamine↗
PubMed1986

Disruption of oligosaccharide processing in murine tumor cells inhibits their susceptibility to lysis by activated mouse macrophages.

The components of tumor cell surfaces that participate in the recognition and lysis of these cells by activated macrophages have not been identified. One plausible hypothesis is that these components are specific carbohydrate structures. As an initial test of this hypothesis, I have made use of the oligosaccharide processing inhibitors 1-deoxynojirimycin (dNM) and 1-deoxymannojirimycin (dMM). dNM is an inhibitor of the glucosidases involved in the initial steps of oligosaccharide processing. dMM inhibits mannosidase I. P815 cells incubated in the presence of 1-2 mM dNM for 24 hr synthesized mature glycoproteins that contained glucosylated high-mannose asparagine-linked oligosaccharides instead of complex forms. The glucosylated oligosaccharides were present in trypsin digests of the cell surface. The dNM treatment resulted in a diminution in the amount of surface galactose residues as evidenced by neuraminidase/galactose oxidase/NaB3H4 labeling of surface glycopeptides. It did not, however, inhibit protein synthesis or alter the surface polypeptide profile of the tumor cells. P815 and R1- cells incubated in the presence of 1-3 mM dNM for 24 hr were considerably less sensitive to lysis by interferon-gamma-activated macrophages than were cells incubated in control medium. At a dNM concentration of 3 mM, a 71% inhibition of P815 cell lysis was observed. Similarly, P815 and R1- cells incubated in the presence of 2 mM dMM were also less sensitive to macrophage-mediated lysis than were control cells. The inhibitors did not affect cell viability, growth, or gross morphology. These observations suggest that complex asparagine-linked oligosaccharides on tumor cell surfaces may participate in recognition and lysis by activated macrophages.

1-Deoxynojirimycin↗
PubMed1987

Regulation of the protein glycosylation pathway in yeast: structural control of N-linked oligosaccharide elongation.

The yeast Saccharomyces cerevisiae X2180 strain with the mnn1 mnn2 mnn9 mutations, all of which affect mannoprotein glycosylation, synthesizes N-linked oligosaccharides having the following structure: (Formula: see text) whereas the mnn1 mnn2 mutant extends the alpha 1----6-linked backbone of some of the core oligosaccharides by adding 20-30 mannose units. Membrane fractions from the mnn1 mnn2 and mnn1 mnn2 mnn9 mutants are equally effective in catalyzing transfer from GDP-[3H]mannose to add mannose in both alpha 1----2 and alpha 1----6 linkages to an oligosaccharide having the following structure: (Formula: see text) but neither membrane preparation can utilize the homologous mnn1 mnn2 mnn9 oligosaccharide as an acceptor. Thus, addition of the alpha 1----2-linked mannose side chain to the terminal alpha 1----6-linked mannose in oligosaccharides of the mnn9 mutant inhibits the elongation reaction and may serve as an important structural control of mannoprotein glycosylation. The mnn9 mutation also increases the transit time for invertase secretion, meaning that this mutation could affect the processing machinery in the Golgi apparatus.

Biological Transport↗
PubMed1997

An important developmental role for oligosaccharides during early embryogenesis of cyprinid fish.

Derivatives of chitin oligosaccharides have been shown to play a role in plant organogenesis at nanomolar concentrations. Here we present data which indicate that chitin oligosaccharides are important for embryogenesis in vertebrates. We characterize chitin oligosaccharides synthesized in vitro by zebrafish and carp embryos in the late gastrulation stage by incorporation of radiolabeled N-acetyl-D-[U14C]glucosamine and by HPLC in combination with enzymatic conversion using the Bradyrhizobium NodZ alpha-1, 6-fucosyltransferase and chitinases. A rapid and sensitive bioassay for chitin oligosaccharides was also used employing suspension-cultured plant cells of Catharanthus roseus. We show that chitin oligosaccharide synthase activity is apparent only during late gastrulation and can be inhibited by antiserum raised against the Xenopus DG42 protein. The DG42 protein, a glycosyltransferase, is transiently expressed between midblastula and neurulation in Xenopus and zebrafish embryogenesis. Microinjection of the DG42 antiserum or the Bradyrhizobium NodZ enzyme in fertilized eggs of zebrafish led to severe defects in trunk and tail development.

Animals↗
PubMed1998

Oligosaccharide sequence of human breast cancer cell heparan sulfate with high affinity for laminin.

Laminin-1 is a basement membrane glycoprotein implicated in tumor-host adhesion, which involves the cell-binding domain(s) of laminin-1 and tumor cell surface heparan sulfate (HS). The specific tumor cell surface HS oligosaccharide sequences that are necessary for binding to laminin-1 have not been characterized. To identify this laminin-binding oligosaccharide sequence, GlcNSO4-rich oligosaccharides terminating with [3H]2,5-anhydromannitol (AManR) residues were isolated from human breast cancer cell (MCF-7)-derived HS through hydrazinolysis/high pH (4.0) nitrous acid treatment/[3H]NaBH4 reduction. These oligosaccharides were chromatographed on a laminin-1 affinity column. A high affinity dodecasaccharide was isolated and characterized. Disaccharide analysis yielded IdoA(2-SO4) --> AManR(6-SO4) as the only disaccharide upon treatment of this dodecasaccharide with nitrous acid at low pH (1.5). The sequence of laminin-binding high affinity oligosaccharide is therefore [IdoA(2-SO4) --> GlcNSO4(6-SO4)]5[IdoA(2-SO4) --> AManR(6-SO4)]. Low affinity dodecasaccharides composed of [IdoA(2-SO4) --> GlcNSO4(6-SO4)]5, [IdoA(2-SO4) --> GlcNSO4] were also isolated by laminin-1 affinity chromatography. Molecular modeling studies indicate that a heparin-binding peptide sequence corresponding to amino acid residues 3010-3031 (KQNCLSSRASFRGCVRNLRLSR) in the G domain of laminin-1, modeled as a right-handed alpha-helix, carries an array of basic residues well placed to bind to clusters of sulfate groups on the high affinity dodecasaccharide.

Amino Acid Sequence↗
PubMed1998

Demonstration of the immature glycosaminoglycan tetrasaccharide sequence GlcAbeta1-3Galbeta1-3Galbeta1-4Xyl on recombinant soluble human alpha-thrombomodulin. An oligosaccharide structure on a "part-time" proteoglycan.

Thrombomodulin (TM), a cell surface glycoprotein, is a critical mediator of endothelial anticoagulant defenses occurring both as a chondroitin sulfate proteoglycan (beta-TM) and a protein (alpha-TM) unsubstituted by chondroitin sulfate (CS), hence its description as a "part-time" proteoglycan (PG) (Fransson, L. A. (1987) Trends Biochem. Sci. 12, 406-411). Sugar analysis was performed on alpha-TM to investigate a possible biosynthetic mechanism for part-time PGs. Recombinant human alpha-TM, which was expressed in CHO-K1 cells, separated by anion-exchange chromatography from beta-TM, and purified by immunoaffinity chromatography (Nawa, K., Sakano, K., Fujiwara, H., Sato, Y., Sugiyama, N., Teruuchi, T., Iwamoto, M., and Marumoto, Y. (1990) Biochem. Biophys. Res. Commun. 171, 729-737), was used for analysis. Preliminary sugar composition analysis after acid hydrolysis showed Xyl in addition to Gal, GalNAc, GlcNAc, Man, Fuc, and Glc. O-Glycosidically-linked oligosaccharides were liberated by mild alkaline treatment and purified. The isolated oligosaccharide fraction was derivatized with a fluorophore 2-aminobenzamide (2AB), resulting in two fluorescent components, a 2AB-oligosaccharide and a putative 2AB-Glc. Based on structural analysis by a combination of sequential exoglycosidase digestion and 500-MHz 1H NMR spectroscopy of the 2AB-oligosaccharide, the structure of the oligosaccharide was elucidated as GlcAbeta1-3Galbeta1-3Galbeta1-4Xyl, which turned out to represent a glycosaminoglycan (GAG)-protein linkage region tetrasaccharide common to various PGs and was considered to be a biosynthetic intermediate of an immature GAG chain. The results may indicate that at least one class of the so-called part-time PGs bear the linkage tetrasaccharide at the GAG attachment sites and that the critical determining step or the rate-limiting step for PG biosynthesis is the transfer of the fifth sugar residue, the first hexosamine, rather than xylose.

Animals↗
PubMed2005

Ligands for the beta-glucan receptor, Dectin-1, assigned using "designer" microarrays of oligosaccharide probes (neoglycolipids) generated from glucan polysaccharides.

Dectin-1 is a C-type lectin-like receptor on leukocytes that mediates phagocytosis and inflammatory mediator production in innate immunity to fungal pathogens. Dectin-1 lacks residues involved in calcium ligation that mediates carbohydrate-binding by classical C-type lectins; nevertheless, it binds zymosan, a particulate beta-glucan-rich extract of Saccharomyces cerevisiae, and binding is inhibited by polysaccharides rich in beta1,3- or both beta1,3- and beta1,6-linked glucose. The oligosaccharide ligands on glucans recognized by Dectin-1 have not yet been delineated precisely. It is also not known whether Dectin-1 can interact with other types of carbohydrates. We have investigated this, since Dectin-1 shows glucan-independent binding to a subset of T-lymphocytes and is involved in triggering their proliferation. Here we assign oligosaccharide ligands for Dectin-1 using the neoglycolipid-based oligosaccharide microarray technology, a unique approach for constructing microarrays of lipid-linked oligosaccharide probes from desired sources. We generate "designer" microarrays from three glucan polysaccharides, a neutral soluble glucan isolated from S. cerevisiae and two bacterial glucans, curdlan from Alcaligenes faecalis and pustulan from Umbilicaria papullosa, and use these in conjunction with 187 diverse, sequence-defined, predominantly mammalian-type, oligosaccharide probes. Among these, Dectin-1 binding is detected exclusively to 1,3-linked glucose oligomers, the minimum length required for detectable binding being a 10- or 11-mer. Thus, the ligands assigned so far are exogenous rather than endogenous. We further show that Dectin-1 ligands, 11-13 gluco-oligomers, in clustered form (displayed on liposomes), mimic the macromolecular beta-glucans and compete with zymosan binding and triggering of tumor necrosis factor-alpha secretion by a Dectin-1-expressing macrophage cell line.

Animals↗
PubMed1991

Radioactive tracer techniques in the sequencing of glycoprotein oligosaccharides.

Complete sequencing of the oligosaccharide units of glycoproteins can be performed by conventional physical techniques if nanomole quantities of pure molecules are available. However, isolation of sufficient quantities of a glycoprotein may not be technically feasible (e.g., the analysis of biosynthetic intermediates, or rare molecules). Alternatively, partial structural analyses may answer the biological question at hand. In both instances, radioactive sugars can be used to metabolically label the oligosaccharide units of a glycoprotein, permitting substantial structural characterization. Several aspects of this approach are discussed in this overview, including selection of the labeled precursor, maximization of uptake and incorporation, determinants of the specificity of labeling, and general principles for the release and structural analysis of labeled oligosaccharides. Particular advantages include simplicity, ease of use without sophisticated instrumentation, and the fact that purification to radiometric homogeneity is sufficient. Radioactive tracer techniques cannot replace conventional approaches to sequencing oligosaccharides. However, they do provide a rapid, relatively simple approach to obtaining considerable information from limited amounts of material. For molecules such as short-lived biosynthetic intermediates, there is no substitute for these techniques. This approach has been responsible for the initial identification and characterization of many novel oligosaccharides of biological interest.

Animals↗