Carbohydrate Interactions (carbohydrate + interaction)

Distribution by Scientific Domains


Selected Abstracts


Aromatic,Carbohydrate Interactions: An NMR and Computational Study of Model Systems

CHEMISTRY - A EUROPEAN JOURNAL, Issue 25 2008
Sophie Vandenbussche Ir.
Abstract The interactions of simple carbohydrates with aromatic moieties have been investigated experimentally by NMR spectroscopy. The analysis of the changes in the chemical shifts of the sugar proton signals induced upon addition of aromatic entities has been interpreted in terms of interaction geometries. Phenol and aromatic amino acids (phenylalanine, tyrosine, tryptophan) have been used. The observed sugar,aromatic interactions depend on the chemical nature of the sugar, and thus on the stereochemistries of the different carbon atoms, and also on the solvent. A preliminary study of the solvation state of a model monosaccharide (methyl ,-galactopyranoside) in aqueous solution, both alone and in the presence of benzene and phenol, has also been carried out by monitoring of intermolecular homonuclear solvent,sugar and aromatic,sugar NOEs. These experimental results have been compared with those obtained by density functional theory methods and molecular mechanics calculations. [source]


Protein,Carbohydrate Interactions in Infectious Diseases.

CHEMMEDCHEM, Issue 4 2007
Edited by Carole
No abstract is available for this article. [source]


X-ray structural analysis of the ligand-recognition mechanism in the dual-affinity labeling of c-type lysozyme with 2,,3,-epoxypropyl ,-glycoside of N -acetyllactosamine

JOURNAL OF MOLECULAR RECOGNITION, Issue 2 2003
Michiro Muraki
Abstract In spite of the belonging to the same c-type lysozyme family, hen egg-white lysozyme (HEWL) was much less susceptible to the dual-affinity labeling with 2,,3,-epoxypropyl ,-glycoside of N -acetyllactosamine (Gal,1,4GlcNAc-Epo) than human lysozyme (HL). The three-dimensional structures of the HEWL labeled with single Gal,1,4GlcNAc-Epo and the Glu102-mutant HL labeled with double Gal,1,4GlcNAc-Epo were determined by X-ray crystallography at resolutions of 1.85 and 2.0,Å, respectively. The overall conformation and the interaction mode of the carbohydrate ligand part in the singly labeled HEWL and the doubly labeled Glu102-mutant HL were basically identical to those of the correspondingly labeled wild-type HL with minor alterations in some stereochemical parameters. A detailed comparison of the structures revealed the key protein,carbohydrate and carbohydrate,carbohydrate interactions essential for the dual labeling. It was suggested that the difference in the efficiency of the dual labeling was caused by the structural difference between Gln104 in HL and Asn103 in HEWL. The relevance to our previous study and the carbohydrate,carbohydrate interaction on cell-surface membranes were discussed. Copyright © 2003 John Wiley & Sons, Ltd. [source]


Egg and sperm recognition systems during fertilization

DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 2008
Noritaka Hirohashi
Fertilization is a programmed process that has many molecules and sequential events amenable to study. The biochemistry of fertilization has identified cellular and acellular components fundamental to the interactions between sperm and egg. Recent studies highlight the molecular details of the species-specificity of fertilization that involve protein,protein and protein,carbohydrate interactions. Although the diversity of structure and mechanism may imply rapid evolution of fertilization proteins, understanding the structure,function relationships has become important. Here, we introduce the molecules controlling the sperm AR, sperm attachment to, and penetration through, the egg investments. [source]


Signal transduction pathways involved in interaction of galactosylceramide/sulfatide-containing liposomes with cultured oligodendrocytes and requirement for myelin basic protein and glycosphingolipids

JOURNAL OF NEUROSCIENCE RESEARCH, Issue 7 2008
Joan M. Boggs
Abstract We showed previously that the addition to cultured oligodendrocytes (OLs) of multivalent carbohydrate in the form of liposomes containing the two major glycosphingolipids (GSLs) of myelin, galactosylceramide (GalC) and cerebroside sulfate (Sulf), or galactose conjugated to bovine serum albumin caused clustering of GalC on the extracellular surface and myelin basic protein (MBP) on the cytosolic surface. Multivalent carbohydrate also caused depolymerization of actin microfilaments and microtubules, indicating that interaction of the carbohydrate with the OL surface transmits a transmembrane signal to the cytoskeleton. In the present study we show that inhibition of GSL synthesis with fumonisin B1 prevents clustering of MBP in GalC/Sulf-negative oligodendrocytes, suggesting that GSLs are required for the effect. Because the effects of multivalent carbohydrate resemble those caused by the addition of anti-GalC/Sulf antibodies to OLs and because GalC and Sulf can interact with each other by trans carbohydrate,carbohydrate interactions across apposed membranes, these results support the conclusion that the OL receptor for GalC/Sulf in liposomes is GalC/Sulf in the OL membrane. Inhibition of MBP expression using MBP siRNA inhibited GalC clustering, suggesting that MBP is required for the effect. We also investigate the signal transduction pathways involved using a number of enzyme inhibitors. These indicated that the Akt and p42/p44 MAPK pathways, Rho GTPases, and GSK-3, are involved, consistent with their known involvement in regulation of the cytoskeleton. These interactions between GalC/Sulf-containing liposomes and the OL membrane may mimic interactions between GalC/Sulf-enriched signaling domains when OL cell membranes or the extracellular surfaces of compact myelin come into contact. © 2008 Wiley-Liss, Inc. [source]


Analysis and validation of carbohydrate three-dimensional structures

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 2 2009
Thomas Lütteke
Knowledge of the three-dimensional structures of the carbohydrate molecules is indispensable for a full understanding of the molecular processes in which carbohydrates are involved, such as protein glycosylation or protein,carbohydrate interactions. The Protein Data Bank (PDB) is a valuable resource for three-dimensional structural information on glycoproteins and protein,carbohydrate complexes. Unfortunately, many carbohydrate moieties in the PDB contain inconsistencies or errors. This article gives an overview of the information that can be obtained from individual PDB entries and from statistical analyses of sets of three-dimensional structures, of typical problems that arise during the analysis of carbohydrate three-dimensional structures and of the validation tools that are currently available to scientists to evaluate the quality of these structures. [source]


Rapid Screening of Lectins for Multivalency Effects with a Glycodendrimer Microarray

CHEMBIOCHEM, Issue 13 2010
Núria Parera Pera Dr.
Abstract Multivalency is an important phenomenon in protein,carbohydrate interactions. In order to evaluate glycodendrimers as multivalent inhibitors of carbohydrate binding proteins, we displayed them on a microarray surface. Valencies were varied from 1 to 8, and corrections were made for the valencies so that all surfaces contained the same amount of the sugar ligand. Five different carbohydrates were attached to the dendrimers. A series of fluorescent lectins was evaluated, and for each of them a binding profile was obtained from a single experiment showing both the specificity of the lectin for a certain sugar and whether it prefers multivalent ligands or not. Very distinct binding patterns were seen for the various lectins. The results were rationalized with respect to the interbinding distances of the lectins. [source]


Gold Glyconanoparticles as Probes to Explore the Carbohydrate-Mediated Self-Recognition of Marine Sponge Cells

CHEMBIOCHEM, Issue 5 2005
Adriana Carvalho de Souza Dr.
Carbohydrate,carbohydrate interactions. TEM imaging shows that gold glyconanoparticles coated with the synthetic disaccharide epitope ,- D -GlcpNAc3S -(1,3)-,- L -Fucp(1,O) (Au- 1,a) can mimic the proteoglycan self-recognition that is responsible for marine sponge cell adhesion. This interaction is highly specific; any structural changes in the disaccharide completely eradicated the self-recognition phenomenon. [source]


Chemoselective Capture of Glycans for Analysis on Gold Nanoparticles: Carbohydrate Oxime Tautomers Provide Functional Recognition by Proteins

CHEMISTRY - A EUROPEAN JOURNAL, Issue 7 2009
Mikkel
Abstract Open or closed: N -Glycosyl oxyamine versus open-chain glycosyl oxime is the key to protein recognition on glyconanoparticles. Unprotected glycans are captured by oxime formation with a novel bifunctional reagent and the resulting glycan-linker conjugates are anchored to gold nanoparticles (AuNPs). These glyconanoparticles maintain the structural integrity of glycans in the study of protein,carbohydrate interactions (see figure). Nanoparticles functionalized with glycans are emerging as powerful solid-phase chemical tools for the study of protein,carbohydrate interactions using nanoscale properties for detection of binding events. Methods or reagents that enable the assembly of glyconanoparticles from unprotected glycans in two consecutive chemoselective steps with meaningful display of the glycan are highly desirable. Here, we describe a novel bifunctional reagent that 1),couples to glycans by oxime formation in solution, 2),aids in purification through a lipophilic trityl tag, and 3),after deprotection then couples to gold nanoparticles through a thiol. NMR studies revealed that these oximes exist as both the open-chain and N -glycosyl oxy-amine tautomers. Glycan-linker conjugates were coupled through displacement of ligands from preformed, citrate-stabilized gold nanoparticles. Recognition of these glycans by proteins was studied with a lectin, concanavalin A (ConA), in an aggregation assay and with a processing enzyme and glucoamylase (GA). We demonstrate that the presence of the N -glycosyl oxy-amines clearly enables functional recognition in sharp contrast to the corresponding reduced oxy-amines. This concept is then realized in a novel reagent, which should facilitate nanoglycobiology by enabling the operationally simple capture of glycans and their biologically meaningful display. [source]