(1)H NMR is now a standard method to determine de novo primary sequence of all sorts of glycans. These last 30 years, tens of thousands of oligosaccharide sequences have been elucidated by NMR spectroscopy in conjunction with other physico-chemical methods including mass spectrometry and gas chromatography. Most of these sequences are now compiled and available in several web databases recently unified in publicly available GlycomeDB, along with sets of experimental data.
View Article and Find Full Text PDFPurifying and analysing sulfated oligosaccharides by mass spectrometry often constitutes a challenge. We present here a single step method to isolate sulfated compounds from a complex mixture of neutral and acidic oligosaccharide-alditols. The strategy relies on the exclusion of sulfated molecules from strong cation exchange resin.
View Article and Find Full Text PDFEggs from Amphibia are surrounded by several layers of jelly that are needed for proper fertilization. Jelly coat is composed of highly glycosylated mucin-type glycoproteins containing up to 60% of carbohydrates, which display a remarkable species-specificity. This material obtained from Triturus alpestris was submitted to reductive beta-elimination and the released oligosaccharide-alditols were further fractionated by HPLC.
View Article and Find Full Text PDFCandida albicans strains consist of serotypes A and B depending on the presence of terminal beta-1,2-linked mannose residues in the acid-stable part of serotype A phosphopeptidomannan (PPM). The distribution of C. albicans serotypes varies according to country and human host genetic and infectious backgrounds.
View Article and Find Full Text PDFWe describe here the structural deciphering of four wasp O-glycans. Following purification of a mixture of glycoproteins from nests of the common wasp Vespula germanica L. (Hymenoptera), their substituting O-glycans were liberated by reducing beta-elimination and characterised using a combination of high resolution NMR and mass spectrometry analyses.
View Article and Find Full Text PDFThe obligate intracellular protozoan Toxoplasma gondii belongs to the phylum Apicomplexa, which is composed of numerous parasites causing major diseases such as malaria, toxoplasmosis and coccidiosis. The life cycle of T. gondii involves developmental processes from one stage to another with both asexual and sexual parasitic forms.
View Article and Find Full Text PDFStudies on Candida albicans phospholipomannan have suggested a novel biosynthetic pathway for yeast glycosphingolipids. This pathway is thought to diverge from the usual pathway at the mannose-inositol-phospho-ceramide (MIPC) step. To confirm this hypothesis, a C.
View Article and Find Full Text PDFThe appearance of multicellular forms of life has been tightly coupled to the ability of an organism to retain its own anatomical integrity and to distinguish self from non-self. Large glycoconjugates, which make up the outermost cell surface layer of all Metazoans, are the primary candidates for the primordial adhesion and recognition functions in biological self-assembly systems. Atomic force microscopy experiments demonstrated that the binding strength between a single pair of Porifera cell surface glyconectin 1 glycoconjugates from Microciona prolifera can hold the weight of 1600 cells, proving their adhesion functions.
View Article and Find Full Text PDFGlyconectins (GNs) represent a new class of proteoglycan-like cell adhesion and recognition molecules found in several Porifera species. Physico-chemical properties of GN carbohydrate moieties, such as size, composition, and resistance to most glycosaminoglycan-degrading enzymes, distinguish them from any other type of known glycoproteins. The molecular mechanism of GN-mediated self/non-self discrimination function is based on highly species-specific and Ca(2+)-dependent GN to GN associations that approach the selectivity of the evolutionarily advanced immunoglobulin superfamily.
View Article and Find Full Text PDFThis study deals with the chemical characterization of an extracellular polysaccharide produced by the unicellular red alga Porphyridium sp. The sugar moiety of this polymer is composed of three neutral monosaccharides (Xyl, Glc, and Gal) and one uronic acid (GlcA). Proteins represent 5.
View Article and Find Full Text PDFThe amphibian Xenopus tropicalis appears an increasingly appealing model for both genetic and developmental biology studies, compared to the related species Xenopus laevis. Study of the glycosylation pattern of its secreted glycoproteins revealed that this species synthesizes large amounts of Lewis(a) epitope, whereas this motif has previously only been identified in animals within the primate lineage. The use of (1)H-nuclear magnetic resonance spectroscopy enabled us to resolve the sequence of three Lewis(a)-bearing O-linked glycans associated with oviducal secretions, out of which one contained the novel sequence Gal(beta 1-3)GlcNAc(beta 1-6)GalNAc-ol.
View Article and Find Full Text PDFAlthough Mycobacterium kansasii has emerged as an important pathogen frequently encountered in immunocompromised patients, little is known about the mechanisms of M. kansasii pathogenicity. Lipoarabinomannan (LAM), a major mycobacterial cell wall lipoglycan, is an important virulence factor for many mycobacteria, as it modulates the host immune response.
View Article and Find Full Text PDFThe eggs of amphibians are surrounded by an extracellular matrix, termed jelly coat, which is mainly composed of hydrated mucin-type glycoproteins. These highly glycosylated molecules are synthesized by the oviduct and play an important role in the fertilization process. From a structural and chemical point of view, these oviducal mucins are very different from one species to another and they could be involved in the species-specificity of gamete interactions or could influence the parasite tropism.
View Article and Find Full Text PDFLewis a and Lewis x oligosaccharides Gal beta 3(Fuc alpha 4)GlcNAc beta 3Gal beta 4Glc and Gal beta 4(Fuc alpha 3)GlcNAc beta 3Gal beta 4Glc are easily isolated as a mixture from biological fluids, including human milk. However, because they behave almost identically in most chromatographic systems, it is difficult to have each of them as a pure compound. Incidentally, we found that they were easily separated by HPLC as glycosynthons [Gal beta 3(Fuc alpha 4)GlcNAc beta 3Gal beta 4Glc-Glp-beta Ala-OBzl and Gal beta 4(Fuc alpha 3)GlcNAc beta 3Gal beta 4Glc-Glp-beta Ala-OBzl] after substitution of the terminal reducing sugar by a short peptide (pyroglutamyl-beta alanyl-O-benzyl ester) in a one-pot two-step reaction (Carbohydr.
View Article and Find Full Text PDFA combination of ion-exchange chromatography and high performance liquid chromatography (HPLC) has been used to separate the reduced oligosaccharides produced by alkaline borohydride degradation of oviducal mucins obtained from the jelly coat of Rana dalmatina. The primary structures of 26 O-glycans were determined by one-dimensional and two-dimensional 1H and 1H13C NMR spectroscopy. As observed for 20 other amphibian species, these carbohydrate chains are highly species-specific.
View Article and Find Full Text PDFThe pathogenic yeast Candida albicans has the ability to synthesize unique sequences of beta-1,2-oligomannosides that act as adhesins, induce cytokine production, and generate protective antibodies. Depending on the growth conditions, beta-1,2-oligomannosides are associated with different carrier molecules in the cell wall. Structural evidence has been obtained for the presence of these residues in the polysaccharide moiety of the glycolipid, phospholipomannan (PLM).
View Article and Find Full Text PDFLipomannan (LM) and lipoarabinomannan (LAM) are major glycolipids present in the mycobacterial cell wall that are able to modulate the host immune response. In this study, we have undertaken the structural determination of these important modulins in Mycobacterium chelonae, a fast growing pathogenic mycobacterial species. One-dimensional and two-dimensional NMR spectra were used to demonstrate that LM and LAM from M.
View Article and Find Full Text PDFThe extracellular matrix (the so-called jelly coat) surrounding amphibian eggs mainly comprises highly O-glycosylated proteins. These oviducal mucins have an important role in the fertilization process, and their carbohydrate chains are remarkably species-specific. Alkaline reductive treatment of the jelly-coat material of the frog Rana clamitans led to the release of oligosaccharide alditols.
View Article and Find Full Text PDFThe jelly coat surrounding the eggs of amphibia is composed of oviducal mucins and plays an important role in the fertilization process. From a structural and chemical point of view, these jellies are very different from one species to another. Bufo viridis is the 13th amphibia species studied in term of carbohydrate structural analysis.
View Article and Find Full Text PDFInterleukin 6 (IL-6) is endowed with a lectin activity for oligosaccharide ligands possessing the HNK-1 epitope (3-sulfated glucuronic acid) found on some mammalian glycoprotein N-glycans (Cebo, C., Dambrouck, T., Maes, E.
View Article and Find Full Text PDF