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Song X, Ju H, Lasanajak Y, Kudelka MR, Smith DF, Cummings RD. Oxidative release of natural glycans for functional glycomics. Nat Methods 2016; 13:528-34. [PMID: 27135973 PMCID: PMC4887297 DOI: 10.1038/nmeth.3861] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 03/28/2016] [Indexed: 12/13/2022]
Abstract
Glycans have essential roles in biology and the etiology of many diseases. A major hurdle in studying glycans through functional glycomics is the lack of methods to release glycans from diverse types of biological samples. Here we describe an oxidative strategy using household bleach to release all types of free reducing N-glycans and O-glycan-acids from glycoproteins, and glycan nitriles from glycosphingolipids. Released glycans are directly useful in glycomic analyses and can be derivatized fluorescently for functional glycomics. This chemical method overcomes the limitations in glycan generation and promotes archiving and characterization of human and animal glycomes and their functions.
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Affiliation(s)
- Xuezheng Song
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Hong Ju
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Yi Lasanajak
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Matthew R Kudelka
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - David F Smith
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Richard D Cummings
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
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2
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Abstract
Selective cleavage of the oligosaccharide moiety of glycolipids for further structural analysis can be achieved by means of endoglycoceramidase (EGCase), an enzyme specific for the linkages between oligosaccharide and ceramide residues in glycolipids. The method described here can be used for analysis of glycolipids present in macroscopic amounts or for glycolipids that have been radiolabeled in their carbohydrate moiety.
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Affiliation(s)
- A E Manzi
- University of California San Diego, La Jolla, California, USA
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3
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Miller-Podraza H, Lanne B, Angström J, Teneberg S, Milh MA, Jovall PA, Karlsson H, Karlsson KA. Novel Binding Epitope for Helicobacter pylori Found in Neolacto Carbohydrate Chains. J Biol Chem 2005; 280:19695-703. [PMID: 15743770 DOI: 10.1074/jbc.m412688200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Helicobacter pylori is a bacterium that colonizes the stomach of a majority of the global human population causing common gastric diseases like ulcers and cancer. It has an unusually complex pattern of binding to various host glycoconjugates including interaction with sialylated, sulfated, and fucosylated sequences. The present study describes an additional binding epitope comprising the neolacto internal sequence of GlcNAcbeta3-Galbeta4GlcNAcbeta. The binding was detected on TLC plates as an interaction with a seven-sugar ganglioside of rabbit thymus. The glycolipid was purified and characterized as Neu5Gcalpha3Galbeta4GlcNAcbeta3Galbeta4GlcNAcbeta3-Galbeta4Glcbeta1Cer with less than 10% of the fraction carrying a repeated lacto (type-1) core chain, Galbeta3Glc-NAcbeta3Galbeta3GlcNAcbeta. After stepwise chemical and enzymatic degradation and structural analysis of products the strongest binder was found to be the pentaglycosylceramide GlcNAcbeta3Galbeta4GlcNAcbeta3Galbeta4Glcbeta1-Cer, whereas the hexa- and tetraglycosylceramides were less active, and the trihexosylceramide was inactive. Further studies revealed that the terminal GlcNAcbeta of the pentaglycosylceramide may be exchanged for either GalNAcbeta3, GalNAcalpha3, or Galalpha3 without loss of the activity. Calculated minimum energy conformers of these four isoreceptors show a substantial topographical similarity suggesting that this binding is a result of a molecular mimicry. Although the glycoconjugate composition of human gastric epithelial cells is not known in detail it is proposed that repeating N-acetyllactosamine units of glycoconjugates may serve as bacterial attachment sites in the stomach.
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Abstract
Sphingosines, or sphingoids, are a family of naturally occurring long-chain hydrocarbon derivatives sharing a common 1,3-dihydroxy-2-amino-backbone motif. The majority of sphingolipids, as their derivatives are collectively known, can be found in cell membranes in the form of amphiphilic conjugates, each composed of a polar head group attached to an N-acylated sphingoid, or ceramide. Glycosphingolipids (GSLs), which are the glycosides of either ceramide or myo-inositol-(1-O)-phosphoryl-(O-1)-ceramide, are a structurally and functionally diverse sphingolipid subclass; GSLs are ubiquitously distributed among all eukaryotic species and are found in some bacteria. Since GSLs are secondary metabolites, direct and comprehensive analysis (metabolomics) must be considered an essential complement to genomic and proteomic approaches for establishing the structural repertoire within an organism and deducing its possible functional roles. The glycosphingolipidome clearly comprises an important and extensive subset of both the glycome and the lipidome, but the complexities of GSL structure, biosynthesis, and function form the outlines of a considerable analytical problem, especially since their structural diversity confers by extension an enormous variability with respect to physicochemical properties. This chapter covers selected developments and applications of techniques in mass spectrometric (MS) that have contributed to GSL structural analysis and glycosphingolipidomics since 1990. Sections are included on basic characteristics of ionization and fragmentation of permethylated GSLs and of lithium-adducted nonderivatized GSLs under positive-ion electrospray ionization mass spectrometry (ESI-MS) and collision-induced mass spectrometry (CID-MS) conditions; on the analysis of sulfatides, mainly using negative-ion techniques; and on selected applications of ESI-MS and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) to emerging GSL structural, functional, and analytical issues. The latter section includes a particular focus on evolving techniques for analysis of gangliosides, GSLs containing sialic acid, as well as on characterizations of GSLs from selected nonmammalian eukaryotes, such as dipterans, nematodes, cestodes, and fungi. Additional sections focus on the issue of whether it is better to leave GSLs intact or remove the ceramide; on development and uses of thin-layer chromatography (TLC) blotting and TLC-MS techniques; and on emerging issues of high-throughput analysis, including the use of flow injection, liquid chromatography mass spectrometry (LC-MS), and capillary electrophoresis mass spectrometry (CE-MS).
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Affiliation(s)
- Steven B Levery
- Department of Chemistry, University of New Hamphsire, Durham, USA
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5
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Manzi AE, Norgard-Sumnicht K, Argade S, Marth JD, van Halbeek H, Varki A. Exploring the glycan repertoire of genetically modified mice by isolation and profiling of the major glycan classes and nano-NMR analysis of glycan mixtures. Glycobiology 2000; 10:669-89. [PMID: 10910972 DOI: 10.1093/glycob/10.7.669] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The production of mice with genetic alterations in glycosyltransferases has highlighted the need to isolate and study complex mixtures of the major classes of oligosaccharides (glycans) from intact tissues. We have found that nano-NMR spectroscopy of whole mixtures of N- and O-glycans can complement HPLC profiling methods for elucidating structural details. Working toward obtaining such glycan mixtures from mouse tissues, we decided to develop an approach to isolate not only N- and O-glycans, but also to separate out glycosphingolipids, glycosaminoglycans and glycosylphosphatidylinositol anchors. We describe here a comprehensive Glycan Isolation Protocol that is based primarily upon the physicochemical characteristics of the molecules, and requires only commonly available reagents and equipment. Using radiolabeled internal tracers, we show that recovery of each major class of glycans is as good or better than with conventional approaches for isolating individual classes, and that cross-contamination is minimal. The recovered glycans are of sufficient purity to provide a "glycoprofile" of a cell type or tissue. We applied this approach to compare the N- and O-glycans from wild type mouse tissues with those from mice genetically deficient in glycosyltransferases. N- and O-glycan mixtures from organs of mice deficient in ST6Gal-I (CMP-Sia:Galbeta1-4GlcNAc alpha2-6 sialyltransferase) were studied by the nano-NMR spectroscopy approach, showing no detectable alpha2-6-linked sialic acids. Thus, ST6Gal-I is likely responsible for generating most or all of these residues in normal mice. Similar studies indicate that this linkage is very rare in ganglioside glycans, even in wild-type tissues. In mice deficient in GalNAcT-8 (UDP-GalNAc:polypeptide O-Ser/Thr GalNAc transferase 8), HPLC profiling indicates that O-glycans persist in the thymus in large amounts, without a major change in overall profile, suggesting that other enzymes can synthesize the GalNAc-O-Ser/Thr linkage in this tissue. These results demonstrate the applicability of nano-NMR spectroscopy to complex glycan mixtures, as well as the versatility of the Glycan Isolation Protocol, which makes possible the concurrent examination of multiple glycan classes from intact vertebrate tissues.
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Affiliation(s)
- A E Manzi
- Departments of Medicine and Cellular and Molecular Medicine, Howard Hughes Medical Institute, University of California San Diego, La Jolla 92093-0687, USA
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Affiliation(s)
- M Basu
- Department of Chemistry and Biochemistry, University of Notre Dame, Indiana 46556-5601, USA
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7
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Wang LX, Pavlova NV, Yang M, Li SC, Li YT, Lee YC. Synthesis of aryl 3'-sulfo-beta-lactosides as fluorogenic and chromogenic substrates for ceramide glycanases. Carbohydr Res 1998; 306:341-8. [PMID: 9648244 DOI: 10.1016/s0008-6215(97)10082-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We have previously reported that 4-methylumbelliferyl 6'-O-benzyl-beta-lactoside (2) is a useful substrate for a fluorometric assay of ceramide glycanase (CGase) (L.-X. Wang, N. V. Pavlova, S.-C. Li, Y.-T. Li and Y. C. Lee, Glycoconjugate J., 13 (1996) 359-365). The introduction of a 6-O-benzyl group at the terminal Gal efficiently protected the substrate from its hydrolysis by exo-galactosidase, permitting the assay of CGase in crude biological materials. However, a drawback of this substrate is its low water-solubility and relatively high Km (at a mM level). Introduction of a sulfate group into 4-methylumbelliferyl beta-lactoside (1) led to the formation of 4-methylumbelliferyl 3'-O-sulfo-beta-lactoside (3), which was found to be a more effective substrate than 2. Moreover, the presence of a 3'-O-sulfate group not only increases the water solubility tremendously, but also protects the substrate from cleavage by exo-beta-galactosidase as the 6'-O-benzyl group in 2 does. In addition to the fluorogenic substrate (3), two sulfated chromogenic substrates, N-tetradecanoyl-4-O(3'-sulfo-beta-lactosyl)-3-nitro-L-tyrosine methyl ester (9) and 2-N-(tetradecanoylamino)-4-nitro-phenyl 3'-sulfo-beta-lactoside (12), were synthesized and their suitability for a photometric assay of CGase was evaluated. Substrates 9 and 12, with a long fatty acid chain attached to the aglycon part, have a Km value close to that of the natural substrate GM1 (at a microM level).
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Affiliation(s)
- L X Wang
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218-2685, USA
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8
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Miller-Podraza H, Stenhagen G, Larsson T, Andersson C, Karlsson KA. Screening for the presence of polyglycosylceramides in various tissues: partial characterization of blood group-active complex glycosphingolipids of rabbit and dog small intestines. Glycoconj J 1997; 14:231-9. [PMID: 9111140 DOI: 10.1023/a:1018545922728] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Twenty different human and animal tissues were investigated for the presence of polyglycosylceramides. The glycolipids were isolated by peracetylation of dry tissue residues left after conventional lipid extraction, followed by extraction with chloroform and subsequent Sephadex LH-20, Sephadex LH-60 and silica gel chromatography. In most of the cases only trace amounts of complex glycolipids were found. Distinct bands of glycosphingolipids migrating on TLC plates in a region of brain gangliosides and below were observed in bovine erythrocytes, human leukocytes and human colon mucosa. Definite fractions of polyglycosylceramides were isolated from rabbit small intestine, dog small intestine, human placenta and human leukocytes. The polyglycosylceramides of dog and rabbit intestine were characterized by colorimetric analysis, methylation analysis, mass spectrometry and immunological assays. The dog material contained branched carbohydrate chains with repeated fucosylated N-acetyllactosamine units. Rabbit intestine polyglycosylceramides resembled rabbit erythrocyte polyglycosylceramides with Hex-Hex- terminal determinants but were more complex in respect of sugar composition and structure. The material isolated from dog intestine showed A, H, Le(x) and Le(y) blood group activities. Polyglycosylceramides of human erythrocytes, placenta and leukocytes showed strong binding affinity for Helicobacter pylori, while polyglycosylceramide fractions from rabbit and dog intestine were receptor-inactive for this bacterium or displayed only weak and poorly reproducible binding.
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9
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Miller-Podraza H, Milh MA, Bergström J, Karlsson KA. Recognition of glycoconjugates by Helicobacter pylori: an apparently high-affinity binding of human polyglycosylceramides, a second sialic acid-based specificity. Glycoconj J 1996; 13:453-60. [PMID: 8781976 DOI: 10.1007/bf00731478] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Helicobacter pylori has been reported to agglutinate erythrocytes and to bind to various other cells in a sialic acid-dependent way. The binding was inhibited by sialyllactose or fetuin and other sialylated glycoproteins. The specificity apparently requires bacterial growth on agar, since we found that it was lost after growth in the nutrient mixture Ham's F12. Instead, the bacteria bound with high affinity and in a sialic acid-dependent way to polyglycosylceramides of human erythrocytes, a still incompletely characterized group of complex glycolipids. Bacteria grown in F12 medium were metabolically labelled with 35S-methionine and analysed for binding to glycolipids on thin-layer chromatograms and to glycoproteins on blots after electrophoresis, with human erythrocyte glycoconjugates in focus. There was no binding to simpler gangliosides including GM3 or sialylparagloboside, or to a mixture of brain gangliosides. In contrast, polyglycosylceramides of human erythrocyte membranes bound at a pmol level. The activity was eliminated by mild acid treatment, mild periodate oxidation or sialidase hydrolysis. Erythrocyte proteins as well as a range of reference glycoproteins did not bind except band 3, which was weakly active. However, this activity was resistant to periodate oxidation. These results indicate a second and novel sialic acid-recognizing specificity which is expressed independently of the previously described specificity.
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10
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Komori H, Ito M. Conversion of short-chain ceramides to short-chain ceramide GM3 in B16 melanoma cells. FEBS Lett 1995; 374:299-302. [PMID: 7589558 DOI: 10.1016/0014-5793(95)01137-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We report that short-chain ceramide (Cer), C2- and C6-Cer, were immediately glycosylated and finally converted to short-chain Cer GM3 in B16 melanoma cells. By addition of either C2- or C6-Cer to a cell culture of B16 melanoma in the presence of [14C]Gal, the radiolabeled precursor, was incorporated into each of two novel glycosphingolipids (GSLs) within 30 min along with synthesis of normal GSLs. These novel GSLs were identified as C2-, C6-Cer cerebrosides and C2-, C6-Cer GM3, respectively. In comparison with C2-Cer, C6-Cer was found to be much more efficiently converted to the GSLs, whereas no glycosylated sphingosine was detectable when it was added in place of short-chain Cer.
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Affiliation(s)
- H Komori
- Laboratory of Marine Biochemistry, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
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11
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Ito M, Kurita T, Kita K. A novel enzyme that cleaves the N-acyl linkage of ceramides in various glycosphingolipids as well as sphingomyelin to produce their lyso forms. J Biol Chem 1995; 270:24370-4. [PMID: 7592649 DOI: 10.1074/jbc.270.41.24370] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We describe a novel enzyme that hydrolyzes the N-acyl linkage between fatty acids and sphingosine bases in ceramides of various sphingolipids. The enzyme was purified about 3000-fold with 5% recovery from the culture filtrate of a newly isolated bacterium (Pseudomonas sp. TK4) by ammonium sulfate precipitation followed by several steps of high performance liquid chromatography. The purified enzyme preparation was completely free of exoglycosidases, sphingomyelinase, and proteases, and showed a single protein band corresponding to a molecular mass of 52 kDa on SDS-polyacrylamide slab gel electrophoresis after staining with Coomassie Brilliant Blue. The enzyme shows quite wide specificity, i.e. it hydrolyzes both neutral and acidic glycosphingolipids, and simple glycosphingolipid cerebrosides to polysialogangliosides such as GQ1b. Furthermore the enzyme also hydrolyzes sphingomyelin to produce the respective lyso form. However, the enzyme shows hardly any activity on ceramides, indicating that it is completely different from the ceramidase (EC 3.5.1.23) reported previously. This enzyme, which is tentatively named sphingolipid ceramide N-deacylase, should greatly facilitate the further study of sphingolipids as well as lysosphingolipids.
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Affiliation(s)
- M Ito
- Laboratory of Marine Biochemistry, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
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12
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Dennis RD, Baumeister S, Smuda C, Lochnit C, Waider T, Geyer E. Initiation of chemical studies on the immunoreactive glycolipids of adult Ascaris suum. Parasitology 1995; 110 ( Pt 5):611-23. [PMID: 7596644 DOI: 10.1017/s0031182000065331] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
There is a general lack of basic information concerning one class of glycoconjugate, the glycolipids, from parasitic nematodes. As the prototype, the neutral glycolipid fraction derived from adult males of Ascaris suum was investigated as to its chromatographic, differential chemical staining, antigenic and chemical properties. The thin-layer chromatography-resolved neutral fraction glycolipids could be classified into components of fast and slow migrating band groups. Immunoreactivity was restricted to the latter as detected by IgG and IgM anti-neutral fraction glycolipid antibody levels in serial infection sera of mice. Similarities of chromatography, antigenicity and serological cross-reactivity have been extended to the neutral glycolipid fractions of other parasitic nematodes: Litomosoides carinii and Nippostrongylus brasiliensis. Chemical, differential chemical staining and enzymatic analyses identified the Ascaris suum antigenic, slow migrating band group of components as amphoteric glycosphingolipids, and not the originally hypothesized glycoglycerolipids or glycosylphosphatidylinositols, that contained typical neutral monosaccharide constituents and a zwitterionic phosphodiester linkage, most probably phosphocholine. Glycosphingolipid-immunoreactivity is eliminated on cleavage of the zwitterionic phosphodiester linkage by hydrofluoric acid treatment.
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Affiliation(s)
- R D Dennis
- Allgemeine und Medizinische Parasitologie, FB Biologie, Philipps-Universität Marburg, Germany
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13
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Ito M, Ikegami Y, Tai T, Yamagata T. Specific hydrolysis of intact erythrocyte cell-surface glycosphingolipids by endoglycoceramidase. Lack of modulation of erythrocyte glucose transporter by endogenous glycosphingolipids. EUROPEAN JOURNAL OF BIOCHEMISTRY 1993; 218:637-43. [PMID: 8269954 DOI: 10.1111/j.1432-1033.1993.tb18417.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
This study represents the specific hydrolysis of cell-surface glycosphingolipids (GSLs) of intact cells by endoglycoceramidase (EGCase; EC.3.2.1.123) which cleaves the linkage between oligosaccharides and ceramides of various GSLs. After a 2-h incubation of horse intact erythrocytes with 20 mU EGCase II in the presence of activator at 37 degrees C, 68% of the N-glycolylneuraminic-acid-containing ganglioside GM3(NeuGc) and 70% of 4-O-acetyl GM3(NeuGc) were found to be hydrolyzed without hemolysis, accompanied by a corresponding increase in ceramide but not sphingosine or N,N-dimethylsphingosine. No hydrolysis was observed for sphingomyelin, phosphatidylcholine, phosphatidylethanolamine, cholesterol or membrane proteins. The decrease in immunoreactivity with GMR8 antibody, specific to NeuGc alpha 2,3Gal- of GM3(NeuGc), corresponded to that of cell-surface GM3(NeuGc) by the enzyme, and almost no immunoreactivity was found when 70% of the GM3(NeuGc) was hydrolyzed. Besides the cell-surface GM3(NeuGc) of horse erythrocytes, Gg3Cer of guinea pig, GM3(NeuAc) and LcCer of human, and bovine and rabbit erythrocyte IV3Gal alpha-nLc4Cer were found to be efficiently hydrolyzed by EGCase II even when present in intact cells, while human erythrocyte Gb4Cer is quite resistant to hydrolysis by the enzyme on the cell surface as well as in detergent micelles. Glucose incorporation via the glucose transporter in erythrocytes was not affected at all by the specific and exhaustive hydrolysis of cell-surface GSLs by EGCase II. This result strongly suggested that glucose transporter function was not directly modulated by endogenous GSLs. In summary, this paper demonstrates that, together with the assistance of activator protein, EGCase II will become a powerful tool for selectively removing sugar chains from cell-surface GSLs without damaging other cell membrane components, and will be useful for describing the biological functions of endogenous GSLs.
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Affiliation(s)
- M Ito
- Laboratory of Glycoconjugate Research, Mitsubishi Kasei Institute of Life Sciences, Tokyo, Japan
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14
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Ito M, Ikegami Y, Yamagata T. Kinetics of endoglycoceramidase action toward cell-surface glycosphingolipids of erythrocytes. EUROPEAN JOURNAL OF BIOCHEMISTRY 1993; 218:645-9. [PMID: 8269955 DOI: 10.1111/j.1432-1033.1993.tb18418.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
As shown in the preceding paper [Ito, M., Ikegami, Y., Tai, T. & Yamagata, T. (1993) Eur. J. Biochem. 218, 637-643], endoglycoceramidase (EGCase; EC.3.2.1.123) was found to hydrolyze the cell-surface glycosphingolipids (GSLs) of erythrocytes without any damage to other cell membrane components. This paper represents the kinetics of EGCase action toward cell-surface GSLs of erythrocytes. Without activator or detergents, cell-surface GSLs were found to be hydrolyzed by EGCase II very slowly at pH 7.0. The initial reaction velocity of EGCase II under this condition was 0.038 pmol.min-1.mU-1 for horse erythrocyte cell-surface GM3 and 0.032 pmol.min-1.mU-1 for guinea pig erythrocyte cell-surface Gg3Cer. The addition of activator protein (60 microM), which stimulates EGCase II in the absence of detergents, increased the initial reaction velocity of the enzyme 616-fold for cell-surface GM3 and 468-fold for Gg3Cer, while no increased hemolysis was observed with the addition of activator. However, even in the presence of the activator, the cell-surface GSLs were very resistant to hydrolysis by EGCase II compared to GSL vesicles (or micelles) under same conditions. In contrast to the activator, Triton X-100 (0.4%, mass/vol.) not only stimulated the enzyme activity but also solubilized erythrocyte GSLs into detergent micelles, inducing further increment of the enzyme reaction velocity. The apparent Km and Vmax values of EGCase II were calculated from the Lineweaver-Burk plot as 47 microM and 35 pmol min-1 mU-1 for horse erythrocyte cell-surface GM3 and 44 microM and 27 pmol.min-1.mU-1 for guinea pig erythrocyte cell-surface Gg3Cer, at pH 7.0 in the presence of activator at a concentration of 60 microM.
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Affiliation(s)
- M Ito
- Laboratory of Glycoconjugate Research, Mitsubishi Kasei Institute of Life Sciences, Tokyo, Japan
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15
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Miller-Podraza H, Andersson C, Karlsson KA. New method for the isolation of polyglycosylceramides from human erythrocyte membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1168:330-9. [PMID: 8323973 DOI: 10.1016/0005-2760(93)90190-k] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A new procedure was developed for the isolation of long-chain, highly polar glycosphingolipids from human erythrocytes. The membrane material left after extraction of membrane lipids with organic solvents was peracetylated in a mixture of formamide, pyridine and acetic anhydride, and the acetylated products were then extracted with chloroform. The material was fractionated and purified by means of Sephadex LH-20, Sephadex LH-60 and silica-gel chromatography. The final preparations were mixtures of highly polar glycosphingolipids containing from 7 to 31 sugar residues relative to sphingosine. GC-MS analysis of the sugar part of the isolated fractions showed the presence of branched polyglycosyl chains of N-acetyllactosaminyl type. Endo-beta-galactosidase (Bacteroides fragilis) liberated from the deacetylated material two glycosphingolipids, which were identified by fast atom bombardment-mass spectrometry as Hex-Cer and HexNAc-Hex-Hex-Cer with sphingosine and mainly 24 and 22 carbon fatty acids. Endoglycoceramidase (Rhodococcus) degraded polyglycosylceramides to free ceramides and free polysaccharides. The released sugars were fractionated by high-pH ion-exchange chromatography into fractions differing in sialic acid content. The procedure presented in this paper can be used for large and small scale preparations of complex glycosphingolipids. It proved to be especially suitable for screening for polyglycosylceramides in different tissues.
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Affiliation(s)
- H Miller-Podraza
- Department of Medical Biochemistry, University of Göteborg, Sweden
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16
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Sjoberg E, Manzi A, Khoo K, Dell A, Varki A. Structural and immunological characterization of O-acetylated GD2. Evidence that GD2 is an acceptor for ganglioside O-acetyltransferase in human melanoma cells. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)41986-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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17
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Activator proteins for glycosphingolipid hydrolysis by endoglycoceramidases. Elucidation of biological functions of cell-surface glycosphingolipids in situ by endoglycoceramidases made possible using these activator proteins. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(20)89537-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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