Glycobiology

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No abstract text is available yet for this article.

No abstract text is available yet for this article.

No abstract text is available yet for this article.

The marine environment, contains plentiful renewable resources, e.g. macroalgae with unique polysaccharides, motivating search for enzymes from marine microorganisms to explore conversion possibilities of the polysaccharides. In this study, the first GH17 glucanosyltransglycosylase, MlGH17B, from a marine bacterium (Muricauda lutaonensis), was characterized. The enzyme was moderately thermostable with Tm at 64.4 °C and 73.2 °C, but an activity optimum at 20 °C, indicating temperature sensitive active site interactions...

Modern glycoproteomics experiments require the use of search engines due to the generation of countless spectra. While these tools are valuable, manual validation of search engine results is often required for detailed analysis of glycopeptides as false-discovery rates are often not reliable for glycopeptide data. Near-isobaric mismatches are a common source of misidentifications for the popular glycopeptide-focused search engine pGlyco3.0, and in this technical note we share a strategy and script that improves the accuracy of the search utilizing two manually validated datasets of the glycoproteins CD16a and HIV-1 Env as proof-of-principle...

O-GlcNAcylation is a dynamic modulator of signaling pathways, equal in magnitude to the widely studied phosphorylation. With the rapid development of tools for its detection at the single protein level, the O-GlcNAc modification rapidly emerged as a novel diagnostic and therapeutic target in human diseases. Yet, mapping the human O-GlcNAcome in various tissues is essential for generating relevant biomarkers. In this study, we used human banked tissue as a sample source to identify O-GlcNAcylated protein targets relevant to human diseases...

CD14 is an innate immune receptor that senses pathogen-associated molecular patterns, such as lipopolysaccharide, to activate the innate immune response. Although CD14 is known to be glycosylated, detailed understanding about the structural and functional significance of this modification is still missing. Herein, an NMR and MS-based study, assisted by MD simulations, has provided a 3D-structural model of glycosylated CD14. Our results reveal the existence of a key N-glycosylation site at Asn282 that exclusively contains unprocessed oligomannnose N-glycans that perfectly fit the concave cavity of the bent-solenoid shaped protein...

GNE myopathy (GNEM) is a late-onset muscle atrophy, caused by mutations in the gene for the key enzyme of sialic acid biosynthesis, UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE). With an incidence of one to nine cases per million it is an ultra-rare, so far untreatable, autosomal recessive disease. Several attempts have been made to treat GNEM patients by oral supplementation with sialic acid precursors (e.g. N-acetylmannosamine, ManNAc) to restore sarcolemmal sialylation and muscle strength...

Glycosylation is a prominent posttranslational modification, and alterations in glycosylation are a hallmark of cancer. Glycan-binding receptors, primarily expressed on immune cells, play a central role in glycan recognition and immune response. Here, we used the recombinant C-type glycan-binding receptors CD301, Langerin, SRCL, LSECtin, and DC-SIGNR to recognize their ligands on tissue microarrays (TMA) of a large cohort (n = 1859) of invasive breast cancer of different histopathological types to systematically determine the relevance of altered glycosylation in breast cancer...

Heparan sulfate (HS) plays its biological functions by interacting with hundreds of secreted extracellular and transmembrane proteins. Interaction with HS has been shown to be required for the normal function of many HS-binding proteins. Receptor for advanced glycation end-product (RAGE) is such a protein, whose activation requires HS-induced oligomerization. Using RAGE as an exemplary protein, we show here the workflow of a simple method of developing and characterizing mAbs that targets the HS-binding site...

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ProGlycProt is a comprehensive database of experimentally validated information about protein glycosylation in prokaryotes, including the glycoproteins, glycosyltransferases, and their accessory enzymes. The first release of ProGlycProt featured experimentally validated information on glycoproteins only. For the second release in 2019, the size and scope of the database were expanded twofold, and experimental data on cognate glycosyltransferases and their accessory proteins was additionally included. The growing research and technology interest in microbial glycoproteins and their enzymes is evident from the steady rise in academic publications and patents in this area...

No abstract text is available yet for this article.

No abstract text is available yet for this article.

No abstract text is available yet for this article.

Influenza A virus (IAV) pandemics result from interspecies transmission events within the avian reservoir and further into mammals including humans. Receptor incompatibility due to differently expressed glycan structures between species has been suggested to limit zoonotic IAV transmission from the wild bird reservoir as well as between different bird species. Using glycoproteomics, we have studied the repertoires of expressed glycan structures with focus on putative sialic acid-containing glycan receptors for IAV in mallard, chicken and tufted duck; three bird species with different roles in the zoonotic ecology of IAV...

Glycans found on receptor tyrosine kinases (RTKs) have emerged as promising targets for cancer chemotherapy, aiming to address issues such as drug resistance. However, to effectively select the target glycans, it is crucial to define the structure and function of candidate glycans in advance. Through mass spectrometric analysis, this study presents a "glycoform atlas" of epidermal growth factor receptor 2 (ErbB2), an RTK targeted for the treatment of ErbB2-positive cancers. Our analysis provides an in-depth and site-specific glycosylation profile, including both asparagine- and serine/threonine-linked glycosylation...

Free polymannose-type oligosaccharides (fOS) are processed by cytosolic enzymes to generate Man 5GlcNAc which is transferred to lysosomes and degraded. Lysosomal fOS import was demonstrated in vitro but is poorly characterized in part due to lack of convenient substrates. As chitooligosaccharides (COS, oligomers β1,4-linked GlcNAc) block [ 3H]Man5GlcNAc transport into lysosomes, we asked if COS are themselves transported and if so, can they be chemically modified to generate fluorescent substrates. We show that COS are degraded by lysosomal hydrolases to generate GlcNAc, and robust ATP-dependent transport of [ 3H]COS2/4 di and tetrasaccharides into intact rat liver lysosomes was observed only after blocking lysosomal [ 3H]GlcNAc efflux with cytochalasin B...

The emergence of SARS-CoV-2 variants alters the efficacy of existing immunity towards the viral spike protein, whether acquired from infection or vaccination. Mutations that impact N-glycosylation of spike may be particularly important in influencing antigenicity, but their consequences are difficult to predict. Here, we compare the glycosylation profiles and antigenicity of recombinant viral spike of ancestral Wu-1 and the Gamma strain, which has two additional N-glycosylation sites due to amino acid substitutions in the N-terminal domain (NTD)...