Synthesis of the O-linked pentasaccharide in glycoproteins of Trypanosoma cruzi and selective sialylation by recombinant trans-sialidase

Carbohydrate Research
Verónica M MendozaR M de Lederkremer

Abstract

The mucin-like glycoproteins of Trypanosoma cruzi have novel O-linked oligosaccharides that are acceptors of sialic acid in the trans-sialidase (TcTS) reaction. The transference of sialic acid from host glycoconjugates to the mucins is involved in infection and pathogenesis. The synthesis of the pentasaccharide, beta-D-Galp-(1-->2)-[beta-D-Galp-(1-->3)]-beta-D-Galp-(1-->6)-[beta-D-Galf-(1-->4)]-D-GlcpNAc and the corresponding alditol, previously isolated by reductive beta-elimination of the mucins, is described. The key step was the 6-O-glycosylation of a easily accessible derivative of beta-D-Galf-(1-->4)-D-GlcpNAc with a beta-D-Galp-(1-->2)-[beta-D-Galp-(1-->3)]-D-Galp donor using the trichloroacetimidate method. The beta-linkage was diastereoselectively obtained by the nitrile effect. The pentasaccharide is the major oligosaccharide in the mucins of T. cruzi, G strain and presents two terminal beta-D-Galp residues for possible sialylation by TcTS. A preparative sialylation reaction was performed with its benzyl glycoside and the sialylated product was isolated and characterized. NMR spectroscopic analysis showed that selective monosialylation occurred at the terminal (1-->3) linked galactopyranose.

References

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Mar 8, 1996·The Journal of Organic Chemistry·Carola Gallo-RodriguezRosa M. de Lederkremer

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Citations

Oct 11, 2014·Organic & Biomolecular Chemistry·Gavin T NobleSimon J Webb
Oct 1, 2011·Chembiochem : a European Journal of Chemical Biology·Roland Schauer, Johannis P Kamerling
Nov 21, 2007·Organic & Biomolecular Chemistry·Vanessa Leiria CampoRobert A Field
Jul 11, 2009·Chembiochem : a European Journal of Chemical Biology·Michele R Richards, Todd L Lowary
May 21, 2019·PLoS Neglected Tropical Diseases·María de Los Milagros CámaraCarlos A Buscaglia
Jun 28, 2012·Organic & Biomolecular Chemistry·Gustavo A KashiwagiCarola Gallo-Rodriguez
Sep 2, 2020·Molecules : a Journal of Synthetic Chemistry and Natural Product Chemistry·María Eugenia Giorgi, Rosa M de Lederkremer
Jan 2, 2010·Carbohydrate Research·Verónica M MendozaCarola Gallo-Rodriguez
Jun 8, 2011·Carbohydrate Research·M Eugenia Giorgi, Rosa M de Lederkremer

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