L-fucose is a common constituent of Asn-linked glycans in vertebrates, invertebrates, and plants, but in fungal glycoproteins, fucose has not been found so far. However, by mass spectrometry we detected N-glycans and O-glycans containing one to six deoxyhexose residues in fruit bodies of several basidiomycetes. The N-glycans of chanterelles (Cantharellus cibarius) contained a deoxyhexose chromatographically identical to fucose and sensitive to α-L-fucosidase. Analysis of individual glycan species by tandem MS, glycosidase digestion, and finally (1)H NMR revealed the presence of L-fucose in α1,6-linkage to an α1,6-mannose of oligomannosidic N-glycans. The substitution by α1,6-mannose of α1,2-mannosyl residues of the canonical precursor structure was yet another hitherto unknown modification. No indication for the occurrence of yet other modifications, e.g. bisecting N-acetylglucosamine, was seen. Besides fucosylated N-glycans, short O-linked mannan chains substituted with fucose were present on chanterelle proteins. Although undiscovered so far, L-fucose appears to represent a prominent feature of protein-linked glycans in the fungal kingdom.
"Thus, GnT I is a key enzyme since it is the first glycosyltransferase occurring in the Golgi apparatus in the GnT I-dependent pathway giving rise to complex N-glycans that are required for normal morphogenesis in pluricellular organisms (Ioffe and Stanley, 1994; Metzler et al., 1994). A sequence encoding for a GnT I is predicted in P. tricornutum (Baïet et al., 2011) but not in C. reinhardtii (Mathieu-Rivet et al., 2013) suggesting that N-linked glycans from these two microalgae could be processed in the Golgi apparatus according to two different pathways, referred to as GnT I-dependent and GnT I-independent pathways (Zhu et al., 2004; Crispin et al., 2006; Grass et al., 2011). "
[Show abstract][Hide abstract] ABSTRACT: Microalgae are currently used for the production of food compounds. Recently, few microalgae species have been investigated as potential biofactories for the production of biopharmaceuticals. Indeed in this context, microalgae are cheap, classified as Generally Recognized As Safe (GRAS) organisms and can be grown easily. However, problems remain to be solved before any industrial production of microalgae-made biopharmaceuticals. Among them, post-translational modifications of the proteins need to be considered. Especially, N-glycosylation acquired by the secreted recombinant proteins is of major concern since most of the biopharmaceuticals are N-glycosylated and it is well recognized that glycosylation represent one of their critical quality attribute. Therefore, the evaluation of microalgae as alternative cell factory for biopharmaceutical productions thus requires to investigate their N-glycosylation capability in order to determine to what extend it differs from their human counterpart and to determine appropriate strategies for remodeling the microalgae glycosylation into human-compatible oligosaccharides. Here, we review the secreted recombinant proteins which have been successfully produced in microalgae. We also report on recent bioinformatics and biochemical data concerning the structure of glycans N-linked to proteins from various microalgae phyla and comment the consequences on the glycan engineering strategies that may be necessary to render those microalgae-made biopharmaceuticals compatible with human therapy.
"UEA-I binding was associated with increased adherence to epithelial cells . Recently mass spectrometry identified í µí»¼1,6-fucose residues in oligomannosylated N-linked glycans of the fungi Cantharellus cibarius . This raises the question on how this type of glycans are presented in the surface of mushrooms, as no FUT8 family member of fucosyltransferases responsible for this linkage has been identified in yeast nor mushrooms . "
[Show abstract][Hide abstract] ABSTRACT: Protein glycosylation pathways are present in all kingdoms of life and are metabolic pathways found in all the life kingdoms. Despite sharing commonalities in their synthesis, glycans attached to glycoproteins have species-specific structures generated by the presence of different sets of enzymes and acceptor substrates in each organism. In this review, we present a comparative analysis of the main glycosylation pathways shared by humans and the fungal pathogen Candida albicans: N-linked glycosylation, O-linked mannosylation and glycosylphosphatidylinositol-anchorage. The knowledge of similarities and divergences between these metabolic pathways could help find new pharmacological targets for C. albicans infection.
International Journal of Microbiology 07/2014; 2014:267497. DOI:10.1155/2014/267497
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