Identification and characterization of a UDP-GalNAc:GlcNAc beta-R beta 1-->4-N-acetylgalactosaminyltransferase from cercariae of the schistosome Trichobilharzia ocellata. Catalysis of a key step in the synthesis of N,N'-diacetyllactosediamino (lacdiNAc)-type glycans.
| Autoři: | Neeleman AP; Department of Medical Microbiology and Parasitology, Vrije Universiteit, Amsterdam, The Netherlands., van der Knaap WP, van den Eijnden DH |
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| Zdroj: | Glycobiology [Glycobiology] 1994 Oct; Vol. 4 (5), pp. 641-51. |
| Způsob vydávání: | Journal Article; Research Support, Non-U.S. Gov't |
| Jazyk: | English |
| Informace o časopise: | Publisher: IRL Press at Oxford University Press Country of Publication: England NLM ID: 9104124 Publication Model: Print Cited Medium: Print ISSN: 0959-6658 (Print) Linking ISSN: 09596658 NLM ISO Abbreviation: Glycobiology Subsets: MEDLINE |
| Imprint Name(s): | Original Publication: Oxford ; New York : IRL Press at Oxford University Press, c1990- |
| Výrazy ze slovníku MeSH: | N-Acetylgalactosaminyltransferases/*metabolism , Polysaccharides/*biosynthesis , Schistosomatidae/*enzymology, Animals ; Carbohydrate Sequence ; Catalysis ; Kinetics ; Magnetic Resonance Spectroscopy ; Molecular Sequence Data ; N-Acetylgalactosaminyltransferases/isolation & purification ; Schistosomatidae/growth & development ; Substrate Specificity |
| Abstrakt: | Three different stages of the avian schistosome Trichobilharzia ocellata appeared to contain a novel N-acetylgalactosaminyltransferase activity. To investigate its function in the biosynthesis of schistosome glycoconjugates, the enzyme was partially purified from cercariae, a free-living stage of the parasite, by affinity chromatography on UDP-Sepharose. Acceptor specificity studies showed that the enzyme catalyses the transfer of N-acetylgalactosamine (GalNAc) from UDP-GalNAc to oligosaccharides, glycopeptides and glycoproteins carrying a terminally beta-linked N-acetylglucosamine (GlcNAc) residue, regardless of the underlying structure. Analysis of the products obtained with GlcNAc and a desialylated and degalactosylated diantennary glycopeptide by 400 MHz 1H-NMR spectroscopy revealed that a GalNAc beta 1-->4GlcNAc (N,N'-diacetyllactosediamine,lacdiNAc) unit was formed. The enzyme can therefore be described as a UDP-GalNAc:GlcNAc beta-R beta 1-->4-N-acetylgalactosaminytransferase (beta 4-GalNAcT). Using specific acceptors, the enzyme could be distinguished from all other beta 4-GalNAcTs described to date, including the one from pituitary gland that is involved in the specific glycosylation of pituitary glycohormones. By contrast, the enzymatic properties of the schistosome beta 4-GalNAcT (except for the sugar-donor specificity) strongly resemble those of the beta 4-galactosyltransferase of higher animals, an enzyme which is known to control the synthesis of Gal1-->4GlcNAc (lacNAc)-type oligosaccharide chains. By analogy, the beta 4-GalNAcT is concluded to control the key step in the synthesis of lacdiNAc-type chains. LacdiNAc-type glycans are also common to the mollusc Lymnaea stagnalis, which is the intermediate host of T.ocellata. It is proposed that the schistosome beta 4-GalNAcT functions in the expression of specific carbohydrate structures that contribute to a molecular mimicry, enabling the schistosome to evade the defence system of the snail host. |
| Substance Nomenclature: | 0 (Polysaccharides) EC 2.4.1.- (N-Acetylgalactosaminyltransferases) EC 2.4.1.92 ((N-acetylneuraminyl)-galactosylglucosylceramide N-acetylgalactosaminyltransferase) |
| Entry Date(s): | Date Created: 19941001 Date Completed: 19950410 Latest Revision: 20220224 |
| Update Code: | 20221213 |
| DOI: | 10.1093/glycob/4.5.641 |
| PMID: | 7881179 |
| Autor: | Neeleman AP; Department of Medical Microbiology and Parasitology, Vrije Universiteit, Amsterdam, The Netherlands., van der Knaap WP, van den Eijnden DH |
| Jazyk: | angličtina |
| Zdroj: | Glycobiology [Glycobiology] 1994 Oct; Vol. 4 (5), pp. 641-51. |
| DOI: | 10.1093/glycob/4.5.641 |
| Abstrakt: | Three different stages of the avian schistosome Trichobilharzia ocellata appeared to contain a novel N-acetylgalactosaminyltransferase activity. To investigate its function in the biosynthesis of schistosome glycoconjugates, the enzyme was partially purified from cercariae, a free-living stage of the parasite, by affinity chromatography on UDP-Sepharose. Acceptor specificity studies showed that the enzyme catalyses the transfer of N-acetylgalactosamine (GalNAc) from UDP-GalNAc to oligosaccharides, glycopeptides and glycoproteins carrying a terminally beta-linked N-acetylglucosamine (GlcNAc) residue, regardless of the underlying structure. Analysis of the products obtained with GlcNAc and a desialylated and degalactosylated diantennary glycopeptide by 400 MHz 1H-NMR spectroscopy revealed that a GalNAc beta 1-->4GlcNAc (N,N'-diacetyllactosediamine,lacdiNAc) unit was formed. The enzyme can therefore be described as a UDP-GalNAc:GlcNAc beta-R beta 1-->4-N-acetylgalactosaminytransferase (beta 4-GalNAcT). Using specific acceptors, the enzyme could be distinguished from all other beta 4-GalNAcTs described to date, including the one from pituitary gland that is involved in the specific glycosylation of pituitary glycohormones. By contrast, the enzymatic properties of the schistosome beta 4-GalNAcT (except for the sugar-donor specificity) strongly resemble those of the beta 4-galactosyltransferase of higher animals, an enzyme which is known to control the synthesis of Gal1-->4GlcNAc (lacNAc)-type oligosaccharide chains. By analogy, the beta 4-GalNAcT is concluded to control the key step in the synthesis of lacdiNAc-type chains. LacdiNAc-type glycans are also common to the mollusc Lymnaea stagnalis, which is the intermediate host of T.ocellata. It is proposed that the schistosome beta 4-GalNAcT functions in the expression of specific carbohydrate structures that contribute to a molecular mimicry, enabling the schistosome to evade the defence system of the snail host. |
| Databáze: | MEDLINE |
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