Special Issue "Glycosylation—The Most Diverse Post-Translational Modification"

A special issue of Biomolecules (ISSN 2218-273X). This special issue belongs to the section "Chemical Biology".

Deadline for manuscript submissions: 15 December 2021.

Special Issue Editors

Prof. Dr. Erika Staudacher
E-Mail Website
Guest Editor
Department of Chemistry, Universitat fur Bodenkultur Wien, Vienna, Austria
Interests: glycobiology; glycosylation; glycosyltransferases
Prof. Dr. Els Van Damme
E-Mail Website
Guest Editor
Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
Interests: lectins; carbohydrate-binding proteins; protein–carbohydrate interactions; carbohydrate recognition; glycosylation; biological activity; physiological importance; defense and immunity; stress proteins; glycobiology
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Guy Smagghe
grade E-Mail Website
Guest Editor
Department Crop Protect, Lab Agrozool, Ghent University, Ghent, Belgium
Interests: crop protect

Special Issue Information

Dear Colleagues,

Glycosylation plays an important role in several types of biological and biochemical recognition processes ranging from fertilization and development to pathological events, such as infection, allergy, inflammation or cancer. Furthermore, the analyses of carbohydrate-based relations (host finding, recognition and invasion) between parasite and their hosts or intermediate hosts are a growing field of interest due to the implications in diagnostics, vaccine development, novel therapies and immune responses. Nowadays, the influence of the glycosylation on the mobility of pathogens between species is of particular interest.

This Special Issue aims to highlight aspects of protein glycosylation in all phyla. Contributions (research articles, reviews, communications) that cover the structural elucidation, the function, the biosynthesis or degradation of glycans and the characterization of enzymes involved in these processes are very welcome, as well as papers dealing with methodical improvements for the analysis of glycans or enzymes recognizing carbohydrate structures.

Prof. Dr. Erika Staudacher
Prof. Dr. Els Van Damme
Prof. Dr. Guy Smagghe
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Biomolecules is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • glycosylation
  • glycobiology
  • N-glycans
  • O-glycans
  • glycosyltransferases
  • glycosidases

Published Papers (3 papers)

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Research

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Article
A Combination of Structural, Genetic, Phenotypic and Enzymatic Analyses Reveals the Importance of a Predicted Fucosyltransferase to Protein O-Glycosylation in the Bacteroidetes
Biomolecules 2021, 11(12), 1795; https://0-doi-org.brum.beds.ac.uk/10.3390/biom11121795 - 30 Nov 2021
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Abstract
Diverse members of the Bacteroidetes phylum have general protein O-glycosylation systems that are essential for processes such as host colonization and pathogenesis. Here, we analyzed the function of a putative fucosyltransferase (FucT) family that is widely encoded in Bacteroidetes protein O-glycosylation [...] Read more.
Diverse members of the Bacteroidetes phylum have general protein O-glycosylation systems that are essential for processes such as host colonization and pathogenesis. Here, we analyzed the function of a putative fucosyltransferase (FucT) family that is widely encoded in Bacteroidetes protein O-glycosylation genetic loci. We studied the FucT orthologs of three Bacteroidetes species—Tannerella forsythia, Bacteroides fragilis, and Pedobacter heparinus. To identify the linkage created by the FucT of B. fragilis, we elucidated the full structure of its nine-sugar O-glycan and found that l-fucose is linked β1,4 to glucose. Of the two fucose residues in the T. forsythia O-glycan, the fucose linked to the reducing-end galactose was shown by mutational analysis to be l-fucose. Despite the transfer of l-fucose to distinct hexose sugars in the B. fragilis and T. forsythia O-glycans, the FucT orthologs from B. fragilis, T. forsythia, and P. heparinus each cross-complement the B. fragilis ΔBF4306 and T. forsythia ΔTanf_01305 FucT mutants. In vitro enzymatic analyses showed relaxed acceptor specificity of the three enzymes, transferring l-fucose to various pNP-α-hexoses. Further, glycan structural analysis together with fucosidase assays indicated that the T. forsythia FucT links l-fucose α1,6 to galactose. Given the biological importance of fucosylated carbohydrates, these FucTs are promising candidates for synthetic glycobiology. Full article
(This article belongs to the Special Issue Glycosylation—The Most Diverse Post-Translational Modification)
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Article
Assaying Paenibacillus alvei CsaB-Catalysed Ketalpyruvyltransfer to Saccharides by Measurement of Phosphate Release
Biomolecules 2021, 11(11), 1732; https://doi.org/10.3390/biom11111732 - 20 Nov 2021
Viewed by 303
Abstract
Ketalpyruvyltransferases belong to a widespread but little investigated class of enzymes, which utilise phosphoenolpyruvate (PEP) for the pyruvylation of saccharides. Pyruvylated saccharides play pivotal biological roles, ranging from protein binding to virulence. Limiting factors for the characterisation of ketalpyruvyltransferases are the availability of [...] Read more.
Ketalpyruvyltransferases belong to a widespread but little investigated class of enzymes, which utilise phosphoenolpyruvate (PEP) for the pyruvylation of saccharides. Pyruvylated saccharides play pivotal biological roles, ranging from protein binding to virulence. Limiting factors for the characterisation of ketalpyruvyltransferases are the availability of cognate acceptor substrates and a straightforward enzyme assay. We report on a fast ketalpyruvyltransferase assay based on the colorimetric detection of phosphate released during pyruvyltransfer from PEP onto the acceptor via complexation with Malachite Green and molybdate. To optimise the assay for the model 4,6-ketalpyruvyl::ManNAc-transferase CsaB from Paenibacillus alvei, a β-d-ManNAc-α-d-GlcNAc-diphosphoryl-11-phenoxyundecyl acceptor mimicking an intermediate of the bacterium’s cell wall glycopolymer biosynthesis pathway, upon which CsaB is naturally active, was produced chemo-enzymatically and used together with recombinant CsaB. Optimal assay conditions were 5 min reaction time at 37 °C and pH 7.5, followed by colour development for 1 h at 37 °C and measurement of absorbance at 620 nm. The structure of the generated pyruvylated product was confirmed by NMR spectroscopy. Using the established assay, the first kinetic constants of a 4,6-ketalpyuvyl::ManNAc-transferase could be determined; upon variation of the acceptor and PEP concentrations, a KM, PEP of 19.50 ± 3.50 µM and kcat, PEP of 0.21 ± 0.01 s−1 as well as a KM, Acceptor of 258 ± 38 µM and a kcat, Acceptor of 0.15 ± 0.01 s−1 were revealed. P. alvei CsaB was inactive on synthetic pNP-β-d-ManNAc and β-d-ManNAc-β-d-GlcNAc-1-OMe, supporting the necessity of a complex acceptor substrate. Full article
(This article belongs to the Special Issue Glycosylation—The Most Diverse Post-Translational Modification)
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Review

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Review
Mollusc N-glycosylation: Structures, Functions and Perspectives
by
Biomolecules 2021, 11(12), 1820; https://0-doi-org.brum.beds.ac.uk/10.3390/biom11121820 (registering DOI) - 03 Dec 2021
Abstract
Molluscs display a sophisticated N-glycan pattern on their proteins, which is, in terms of involved structural features, even more diverse than that of vertebrates. This review summarises the current knowledge of mollusc N-glycan structures, with a focus on the functional aspects of the [...] Read more.
Molluscs display a sophisticated N-glycan pattern on their proteins, which is, in terms of involved structural features, even more diverse than that of vertebrates. This review summarises the current knowledge of mollusc N-glycan structures, with a focus on the functional aspects of the corresponding glycoproteins. Furthermore, the potential of mollusc-derived biomolecules for medical applications is addressed, emphasising the importance of mollusc research. Full article
(This article belongs to the Special Issue Glycosylation—The Most Diverse Post-Translational Modification)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: Structural differences between non-sialylated and de-sialylated N-glycans of the human brain revealed by standardized graphitic carbon chromatography
Authors: Johannes Helm; Friedrich Altmann
Affiliation: Altmann lab at BOKU Vienna
Abstract: The brain N-glycome is known to be crucial for many biological functions, including the involvement in neuronal diseases. Although large structural studies of brain N-glycans were recently carried out, a deep isomer-specific analysis with definitive structures given is still required, as indicated by the recent discovery of novel structures with galactosylated bisecting GlcNAc. Here, we present a detailed, isomer-specific analysis of the human brain N-glycome based on standardized porous graphitic carbon (PGC)-LC-MS/MS. To achieve this goal, we biosynthesized glycans with substitutions typically occurring in the brain N-glycome and acquired their normalized retention times. Comparison of these values with the standardized retention times of neutral and desialylated N-glycan fractions of human brain led to an unambiguous assignment of most peaks, including linkage-isomers. Fundamental differences in the glycan-structures between the “naturally neutral” and desialylated glycans were found at the composition- and isomer-level. Arguably, the neutral and sialylated N-glycans derive from diverging biosynthetic pathways and are biosynthetically finished end products rather than just intermediates on their way to sialylation. Furthermore, the presented method proved to be a powerful tool for structural glycomics as substantiated also by the unveiling of four HNK-1 containing N-glycans.

Title: O-methylated N-glycans distinguish mosses from higher land plants
Authors: David Stenitzer; Reka Moscai; Eva Decker; Friedrich Altmann
Affiliation: Altmann lab at BOKU Vienna
Abstract: A stunning variety of N-glycan structures has emerged in the animal kingdom. In plants, however, N-glycosylation appears as conservative and strictly uniform. From archaic land plants to all kinds of gymno- and angiosperms, land plants express structures with the common pentasaccharide core substituted with xylose, core α1,3-fucose, terminal GlcNAc residues and Lewis A determinants. In contrast, green algae – though being “lower” plants - biosynthesize a plethora of species-specific unusual N-glycan structures, often with O-methylation. Mosses, a group of phylogenetically ancient land plants, were hitherto seen as harboring a N-glycosylation machinery identical to that of higher land plants. We have, however, analyzed the N-glycomes of several moss species using MALDI-TOF/TOF, PGC-MS/MS and GC-MS. While all species contained the plant-typical heptasaccharide with no, one or two terminal GlcNAc residues, many species exhibited MS signals with 14.02 Da increments as characteristic for O-methylation. Throughout all analyzed moss N-glycans the level of methylation differed strongly even in the same family. This first finding of methylation of N-glycans in land plants reminds of the presumable phylogenetic relation of mosses to green algae, where O-methylation of mannose and many other monosaccharides is a common trait.

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