Search results for "glycosylation"

Carbohydrate-deficient glycoprotein syndromes: The Italian experience

2000

Microarray analysis of antibodies induced with synthetic antitumor vaccines : specificity against diverse mucin core structures

2017

Glycoprotein research is pivotal for vaccine development and biomarker discovery. Many successful methodologies for reliably increasing the antigenicity toward tumor-associated glycopeptide structures have been reported. Deeper insights into the quality and specificity of the raised polyclonal, humoral reactions are often not addressed, despite the fact that an immunological memory, which produces antibodies with cross-reactivity to epitopes exposed on healthy cells, may cause autoimmune diseases. In the current work, three MUC1 antitumor vaccine candidates conjugated with different immune stimulants are evaluated immunologically. For assessment of the influence of the immune stimulant on a…

Secretion and antigenicity of hepatitis B virus small envelope proteins lacking cysteines in the major antigenic region.

1995

Abstract Disulfide bonds are of crucial importance for the structure and antigenic properties of the hepatitis B virus (HBV) envelope. We have evaluated the role of the eight highly conserved cysteines of the major antigenic region for assembly, secretion, and antigenicity of the envelope proteins. Mutants carrying single or multiple substitutions of alanine for cysteine were analyzed using epitope tagging and transient expression in COS-7 cells. The only single cysteines found to be indispensable for efficient secretion were Cys-107 and Cys-138, but double mutation of Cys-137 and Cys-139 also created a block to secretion. Poorly secreted mutants formed aberrant oligomeric structures. The a…

Secretion, interaction and assembly of two O-glycosylated cell wall antigens from Candida albicans.

2001

The mechanisms of incorporation of two antigens have been determined using a monoclonal antibody (3A10) raised against the material released from the mycelial cell wall by zymolyase digestion and retained on a concanavalin A column. One of the hybridomas secreted an IgG that reacted with two bands in Western blots. Indirect immunofluorescence showed that the antigens were located on the surfaces of mycelial cells, but within the cell walls of yeasts. These antigens were detected in a membrane preparation, in the SDS-soluble material and in the material released by a 1,3-beta-glucanase and chitinase from the cell walls of yeast and mycelial cells. In the latter three samples, an additional h…

Shell matrices of recent rhynchonelliform brachiopods: microstructures and glycosylation studies.

2007

ABSTRACTLike most metazoan biomineralisations, the brachiopod shell is the end product of a biologically controlled calcification process. The main agent of the control is the extracellular matrix, which is secreted by the outer mantle epithelium. This matrix mediates the calcification process by allowing crystal nucleation and elongation in specific orientations and finally, by stopping crystal growth. The proteinaceous moiety of brachiopod shell matrices has been extensively studied. Less known are the post-translational modifications that occur in these matrices, in particular glycosylations. In this comparison of five species of Recent articulated brachiopods, the ratio of soluble to in…

Molecular and Functional Characterisation of Hemocyanin of the Giant African Millipede Archispirostreptus gigas

2013

SummaryIn contrast to other terrestrial arthropods where gaseous O2 that fuels aerobic metabolism diffuses to the tissues in tracheal tubes, and most other metazoans where O2 is transported to tissues by circulating respiratory proteins, the myriapods (millipedes and centipedes) strikingly have tracheal systems as well as circulating hemocyanin (Hc). In order to elucidate the evolutionary origin and biological significance of millipede Hc we report the molecular structure (subunit composition and amino acid sequence) of multimeric (36-mer) Hc from the forest-floor dwelling giant African millipede Archispirostreptus gigas and its allosteric oxygen binding properties under various physico-che…

Natural Triterpene Glycosides for Antibody Recognition

2016

Multiple sclerosis is an autoimmune disease that affects the central nervous system. The key role of the glycosylation in disease pathogenesis has been previously studied and the synthetic N-glucosylated peptide CSF114(Glc) proved its efficiency in autoantibody recognition in the sera of multiple sclerosis patients. Herein, pure natural triterpene glycosides containing different glycosyl moieties were isolated and tested in multiple sclerosis patientsʼ sera to better understand the role of glycosylation. They were selected taking into account the nature and complexity of their osidic part. Five triterpene glycosides were isolated from several plants with more than 95 % purity. The interacti…

Glycosyl azides as building blocks in convergent syntheses of oligomeric lactosamine and Lewisx saccharides

1997

Abstract Oligosaccharides containing type 2 lactosamine repeating units, e.g. neo-lacto-octaose and trimeric Lewis x derivatives, are constructed using neo-lactosamine azide building blocks. The azido group provides a favorable protection of the anomeric position which is stable to versatile protecting group manipulations and glycosylation reactions. On the other hand, glycosyl azides can be converted into glycosyl fluorides via a 1,3-dipolar cycloaddition with di- tert -butyl-acetylenedicar☐ylate and subsequent treatment of the resulting N -glycosyl triazoles with hydrogen fluoride-pyridine complex. Activation of the lactosamine fluorides with Lewis acids affords the possibility to extend …

A new method of anomeric protection and activation based on the conversion of glycosyl azides into glycosyl fluorides

1993

Glycosyl azides provide reliable anomeric protection stable to conditions for hydrolytic removal of ester groups, for reductive opening or release of acetalic diol protection, for the introduction of ether-type protection, and for glycosylation processes. The utility of this anomeric protection is further enhanced as glycosyl azides may be converted into glycosyl fluorides, which can be activated for glycosylation reactions. To this end, glycosyl azides have been subjected to 1,3-dipolar cycloaddition with di-tert-butyl acetylenedicarboxylate. On treatment with hydrogen fluoride-pyridine complex the N-glycosyl triazole derivatives directly give glycosyl fluorides.

Synthesis and characterisation of N-glycosyl amines from the reaction between 4,6-O-benzylidene-D-glucopyranose and substituted aromatic amines and a…

2001

Twelve N-glycosyl amines were synthesised using 4,6-O–benzylidene-D-glucopyranose and different substituted aromatic amines, including some diamines that resulted in bis-glycosyl amines. Another set of six N–glycosyl amines was synthesised using different hexoses and pentoses and 2–(o–aminophenyl)benzimidazole. All compounds were isolated as solid products and purified, their elemental compositions were established, and these were characterised by NMR (1H and 13C), UV–Vis, and FTIR spectroscopy, by FAB mass spectrometry (molecular-ion peaks gave molecular weights), and by their optical rotations. While the protected saccharide, 4,6-O-benzylidene-D-glucopyranose, exists as a mixture of β and…