C-Mannosylation Enhances the Structural Stability of Human RNase 2.

C-Mannosylation is a relatively rare form of protein glycosylation involving the attachment of an α-mannopyranosyl residue to C-2 of the indole moiety of the amino acid tryptophan. This type of linkage was initially discovered in RNase 2 from human urine but later confirmed to be present in many other important proteins. Based on NMR experiments and extensive molecular dynamics simulations on the hundred microsecond timescale we demonstrate that, for isolated glycopeptides and denatured RNase 2, the C-linked mannopyranosyl residue exists as an ensemble of conformations, among which C is the most abundant.

EUROCarbDB: An open-access platform for glycoinformatics.

The EUROCarbDB project is a design study for a technical framework, which provides sophisticated, freely accessible, open-source informatics tools and databases to support glycobiology and glycomic research. EUROCarbDB is a relational database containing glycan structures, their biological context and, when available, primary and interpreted analytical data from high-performance liquid chromatography, mass spectrometry and nuclear magnetic resonance experiments. Database content can be accessed via a web-based user interface.

Insights into the dynamics and molecular recognition features of glycopeptides by protein receptors: the 3D solution structure of hevein bound to the trisaccharide core of N-glycoproteins.

Protein-carbohydrate interactions are at the heart of a variety of essential molecular recognition events. Hevein, a model lectin related to the superantigen family, recognizes the trisaccharide core of N-glycoproteins (1). A combined approach of NMR spectroscopy and molecular modeling has permitted us to demonstrate that an Asn-linked Man(GlcNAc)(2) (2) is bound with even higher affinity than (GlcNAc)(3).

Development of a 1H NMR structural-reporter-group concept for the primary structural characterisation of alpha-D-glucans.

An NMR study of proton chemical shift patterns of known linear alpha-D-glucopyranose di- and trisaccharide structures was carried out. Chemical shift patterns for (alpha1-->2)-, (alpha1-->3)-, (alpha1-->4)- and (alpha1-->6)-linked D-glucose residues were analysed and compared to literature data. Using these data, a 1H NMR structural-reporter-group concept was formulated to function as a tool in the structural analysis of alpha-D-glucans.

The structural basis of the difference in sensitivity for PNGase F in the de-N-glycosylation of the native bovine pancreatic ribonucleases B and BS.

In glycoanalysis protocols, N-glycans from glycoproteins are most frequently released with peptide- N (4)-( N-acetyl-beta-glucosaminyl)asparagine amidase F (PNGase F). As the enzyme is an amidase, it cleaves the NH-CO linkage between the Asn side chain and the Asn-bound GlcNAc residue. Usually, the enzyme has a low activity, or is not active at all, on native glycoproteins.