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Maës, Emmanuel; Florea, Doina; Delplace, Florence; Lemoine, Jérôme; Plancke, Yves; Strecker, Gérard

doi:10.1023/a:1018577302255

Cited by 33 publications

(13 citation statements)

References 20 publications

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“…As shown in Table IV, this structural motif was scarcely expressed in the ileum but was increased in other parts in proportion to the expression of sialylated oligosaccharide alditols. These downfield chemical shifts were always identical in such cases (37,38). Moreover, in sigmoid and rectum parts of donor 2, two correlated protons were observed at ␦ ϭ 4.35 and 4.23 ppm, corresponding to H-6 and H-6Ј of a 6-O-sulfated GlcNAc.…”

Section: Nmr Spectroscopymentioning

confidence: 82%

Evidence of Regio-specific Glycosylation in Human Intestinal Mucins

Robbe

Capon

Maës

et al. 2003

Journal of Biological Chemistry

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187

101

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Mucin glycans were isolated from different regions of the normal human intestine (ileum, cecum, transverse and sigmoid colon, and rectum) of two individuals with ALe b blood group. A systematic study of the monosaccharides and oligosaccharide alditols released by reductive ␤-elimination from mucins was performed using gas chromatography, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, and nuclear magnetic resonance spectroscopy techniques. Important variations were observed in the mucin-associated oligosaccharide content with an increasing gradient of sialic acid from the ileum to the colon associated with a reverse gradient of fucose. Moreover, a comparative study of the Sda/Cad and ABH blood group determinants along the gastrointestinal tract showed the same reverse distribution in the two kinds of antigens. In addition, besides their heterogeneity, sialic acids presented considerable variations in the degree of O-acetylation in relation to glycan sialylation level. These data are discussed in view of recent concepts suggesting that the oligosaccharide composition of the gut constitutes a varied ecosystem for microorganisms that are susceptible to adapt there and possess the specific adhesion system and specific enzymes able to provide a carbohydrate nutrient.Mucins are very high molecular weight glycoproteins secreted by mucosae or some exocrine glands into the lumen of the respiratory, gastrointestinal, and reproductive tracts (1). They consist of a protein backbone with hundreds of carbohydrate side chains of varying lengths, sequences, compositions, and anomeric linkages. A distinguishing feature of mucins is that they contain O-linked oligosaccharides, i.e. the sugar chains are attached to the peptide backbone via a O-glycosidic linkage between a Ser or Thr residue and a GalNAc 1 residue.Intestinal mucins are mainly produced by goblet cells but also by enterocytes and occur both as soluble-secreted and membrane-bound forms. High glycosylation and high mass structures give the mucins gel-forming abilities and other general physical properties that have been regarded as having a protective and rheological function at mucosal surfaces (2). The identification of several different encoded mucins and an enormous repertoire of possible mucin oligosaccharides indicate that the tasks for these glycoproteins may be more subtle than their macroscopic properties suggest. Indeed, mucins may also provide precise structural information carried in determinants among their glycans and in the peptide core, which could mediate specific binding of antibodies, pathogenic microbes, and leukocytes, and may be important in host-pathogen interactions, inflammation, and cancer metastasis (3)(4)(5)(6)(7)(8).Consistent data indicate that mucin genes are expressed in a regulated cell-and tissue-specific manner in the intestine. In situ hybridization has demonstrated that MUC2 is expressed only in goblet cells in the intestine, whereas MUC3 is expressed in both goblet cells and absorptive cells (9). Moreo...

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Section: Nmr Spectroscopymentioning

confidence: 82%

Evidence of Regio-specific Glycosylation in Human Intestinal Mucins

Robbe

Capon

Maës

et al. 2003

Journal of Biological Chemistry

Self Cite

187

101

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“…[1- 14 C]Man (2.07 GBq/mmol) was purchased from American Radiolabeled Chemicals, Inc. 1,2-Diamino-4,5-methylenedioxybenzene (DMB), CMP-Neu5Ac, ATP, hexokinase (bakers' yeast), and N-acetylneuraminic acid aldolase from Escherichia coli were purchased from Wako Pure Chemicals (Japan). Sodium phosphoenolpyruvate, alkaline phosphatase from calf intestine, and Man-6-P were purchased from Sigma.…”

Section: Methodsmentioning

confidence: 99%

Biosynthesis of KDN (2-Keto-3-deoxy-d-glycero -d-galacto -nononic acid)

Angata¹,

Nakata²,

Matsuda³

et al. 1999

Journal of Biological Chemistry

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Although the deaminoneuraminic acid or KDN glycotope (2-keto-3-deoxy-D-glycero-D-galacto-nononic acid)is expressed in glycoconjugates that range in evolutionary diversity from bacteria to man, there is little information as to how this novel sugar is synthesized. Accordingly, biosynthetic studies were initiated in trout testis, an organ rich in KDN, to determine how this sialic acid is formed. These studies have shown that the pathway consists of the following three sequential reactions: 1) Man ؉ ATP 3 Man-6-P ؉ ADP; 2) Man-6-P ؉ PEP 3 KDN-9-P ؉ Pi; 3) KDN-9-P 3 KDN ؉ Pi. Reaction 1, catalyzed by a hexokinase, is the 6-O-phosphorylation of mannose to form D-mannose 6-phosphate (Man-6-P). Reaction 2, catalyzed by KDN-9-phosphate (KDN-9-P) synthetase, condenses Man-6-P and phosphoenolpyruvate (PEP) to form KDN-9-P. Reaction 3, catalyzed by a phosphatase, is the dephosphorylation of KDN-9-P to yield free KDN. It is not known if a kinase specific for Man (Reaction 1) and a phosphatase specific for KDN-9-P (Reaction 3) may exist in tissues actively synthesizing KDN. In this study, the KDN-9-P synthetase, an enzyme that has not been previously described, was identified as at least one key enzyme that is specific for the KDN biosynthetic pathway. This enzyme was purified 50-fold from rainbow trout testis and characterized. The molecular weight of the enzyme was estimated to be about 80,000, and activity was maximum at neutral pH in the presence of Mn 2؉ . N-Acetylneuraminic acid 9-phosphate (Neu5Ac-9-P) synthetase, which catalyzes the condensation of N-acetyl-D-mannosamine 6-phosphate and phosphoenol-pyruvate to produce Neu5Ac-9-P, was co-purified with the KDN-9-P synthetase. Substrate competition experiments revealed, however, that syntheses of KDN-9-P and Neu5Ac-9-P were catalyzed by two separate synthetase activities. The significance of these studies takes on added importance with the recent discovery that the level of free KDN is elevated in human fetal cord but not matched adult red blood cells and (25), , and KDN residue-cleaving sialidases (29 -31), have been identified and partially characterized, and their similarity and dissimilarity to the metabolism of Neu5Acyl residues have been described. In marked contrast, nothing is known concerning how the KDN monosaccharide is synthesized. Two pathways are possible for synthesis of the KDN monomer. First, it could be formed directly from Neu5Ac by deacylation and deamination. Alternatively, it could arise by de novo synthesis via enzymes different from those required for synthesis of Neu5Ac. However, no evidence for the direct conversion of Neu5Ac to KDN has been obtained in any tissue homogenates examined to date. Thus, de novo synthesis by a separate pathway appears to be plausible by analogy with synthesis of other ulosonic acids. For example, 3-deoxy-D-arabino-heptulosonic acid 7-phosphate, a biosynthetic precursor of aromatic amino acids (32), 3-deoxy-D-manno-octulosonic acid, a constituent of bacterial lipopolysaccharides (33, 34) and Neu5Ac (35) are synthesi...

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“…Le y in Pleurodeles waltl mucin [6,7]) prompted us to investigate new amphibian species. These first analyses, which were performed on urodeles and anouran species, led to the observation of a species-specific structural diversity which should be used as a basis for taxonomy [8][9][10][11][12][13][14][15][16]. The present paper describes the O-linked carbohydrate chains of the mucin collected from Rana utricularia egg jelly coats.…”

Section: Introductionmentioning

confidence: 93%

Structural analysis of the oligosaccharide-alditols released by reductive β-elimination from the jelly coat of Rana utricularia eggs

Morelle

Strecker²

1997

Biochemical Journal

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The O-linked oligosaccharides of the jelly coat surrounding the eggs of Rana utricularia were analysed by 1H-NMR spectroscopy. Comparison of their structures with those characterized from seven other amphibians confirms that the carbohydrate chains of the jelly coat mucins are markers of the species. The new sequence GlcNAc(beta1-3)GlcNAc(beta1-6)[Gal(beta1-3)]GalNAc-ol is characteristic of Rana utricularia. The presence of blood group A determinants constitutes the main feature of this mucin.

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Untitled

Cited by 33 publications

References 20 publications

Evidence of Regio-specific Glycosylation in Human Intestinal Mucins

Evidence of Regio-specific Glycosylation in Human Intestinal Mucins

Biosynthesis of KDN (2-Keto-3-deoxy-d-glycero -d-galacto -nononic acid)

Structural analysis of the oligosaccharide-alditols released by reductive β-elimination from the jelly coat of Rana utricularia eggs

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