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Glycoconjugate Journal Jun 2023The structure and properties of a group of gangliosides modified by mild alkaline treatment are discussed. We will present the occurrence and the structure of... (Review)
Review
The structure and properties of a group of gangliosides modified by mild alkaline treatment are discussed. We will present the occurrence and the structure of gangliosides carrying the N-acetyneuraminic acid O-acetylated in position 9, the Neu5,9Ac, and of gangliosides carrying a sialic acid that forms a lactone ring. Starting from biochemical data we will discuss the possible biochemical role played by these gangliosides in the processes of cell signaling and maintenance of brain functions.
Topics: Gangliosides; N-Acetylneuraminic Acid; Sialic Acids; Acetylation
PubMed: 36695939
DOI: 10.1007/s10719-023-10103-0 -
Glycobiology Oct 2022N-glycolylated carbohydrates are amino sugars with an N-glycolyl amide group. These glycans have not been well studied due to their surprising rarity in nature in... (Review)
Review
N-glycolylated carbohydrates are amino sugars with an N-glycolyl amide group. These glycans have not been well studied due to their surprising rarity in nature in comparison with N-acetylated carbohydrates. Recently, however, there has been increasing interest in N-glycolylated sugars because the non-human sialic acid N-glycolylneuraminic acid (Neu5Gc), apparently the only source of all N-glycolylated sugars in deuterostomes, appears to be involved in xenosialitis (inflammation associated with consumption of Neu5Gc-rich red meats). Xenosialitis has been implicated in cancers as well as other diseases including atherosclerosis. Furthermore, metabolites of Neu5Gc have been shown to be incorporated into glycosaminoglycans (GAGs), resulting in N-glycolylated GAGs. These N-glycolylated GAGs have important potential applications, such as dating the loss of the Neu5Gc-generating CMAH gene in humans and being explored as a xenosialitis biomarker and/or estimate of the body burden of diet-derived Neu5Gc, to understand the risks associated with the consumption of red meats. This review explores N-glycolylated carbohydrates, how they are metabolized to N-glycolylglucosamine and N-glycolylgalactosamine, and how these metabolites can be incorporated into N-glycolylated GAGs in human tissues. We also discuss other sources of N-glycolylated sugars, such as recombinant production from microorganisms using metabolic engineering as well as chemical synthesis.
Topics: Humans; Neuraminic Acids; N-Acetylneuraminic Acid; Amino Sugars; Polysaccharides; Inflammation
PubMed: 35925816
DOI: 10.1093/glycob/cwac048 -
Organic Letters Nov 2014The first synthesis of 1,2-trans-homoiminosugars devised as mimics of β-D-GlcNAc and α-D-ManNAc is described. Key steps include a regioselective azidolysis of a cyclic...
The first synthesis of 1,2-trans-homoiminosugars devised as mimics of β-D-GlcNAc and α-D-ManNAc is described. Key steps include a regioselective azidolysis of a cyclic sulfite and a β-amino alcohol skeletal rearrangement applied to a polyhydroxylated azepane. The β-D-GlcNAc derivative has been coupled to serine to deliver an iminosugar C-amino acid. The two homoiminosugars demonstrate moderate glycosidase inhibition.
Topics: Amino Alcohols; Enzyme Inhibitors; Galactosamine; Glucosamine; Glycoside Hydrolases; Heterocyclic Compounds; Magnetic Resonance Spectroscopy; Molecular Structure
PubMed: 25330462
DOI: 10.1021/ol502929h -
Current Opinion in Structural Biology Jun 2019Glycosylation, or the addition of sugars to proteins, is a highly conserved protein modification defined by both the monosaccharide initially added as well as the amino... (Review)
Review
Glycosylation, or the addition of sugars to proteins, is a highly conserved protein modification defined by both the monosaccharide initially added as well as the amino acid to which it is attached. O-Linked glycosylation represents a diverse group of protein modifications occurring on the hydroxyl groups of serine and/or threonine residues. O-Glycosylation can have wide-ranging effects on protein stability and function, which translate into crucial consequences at the organismal level. This review will summarize structural and biological insights into the major O-glycans formed within the secretory apparatus (O-GalNAc, O-Man, O-Fuc, O-Glc and extracellular O-GlcNAc) from studies in the fruit fly Drosophila melanogaster. Drosophila has many advantages for investigating these complex modifications, boasting reduced functional redundancy within gene families, reduced length/complexity of glycan chains and sophisticated genetic tools. Gaining an understanding of the normal cellular and developmental roles of these conserved modifications in Drosophila will provide insight into how changes in O-glycans are involved in human disease and disease susceptibilities.
Topics: Acetylglucosamine; Animals; Drosophila melanogaster; Extracellular Space; Glycosylation; Humans; Oxygen
PubMed: 30852302
DOI: 10.1016/j.sbi.2019.01.014 -
Carbohydrate Research Nov 2016Amino sugars are important constituents of a number of biomacromolecules and products of microbial secondary metabolism, including antibiotics. For most of them, the... (Review)
Review
Amino sugars are important constituents of a number of biomacromolecules and products of microbial secondary metabolism, including antibiotics. For most of them, the amino group is located at the positions C1, C2 or C3 of the hexose or pentose ring. In biological systems, amino sugars are formed due to the catalytic activity of specific aminotransferases or amidotransferases by introducing an amino functionality derived from L-glutamate or L-glutamine to the keto forms of sugar phosphates or sugar nucleotides. The synthetic introduction of amino functionalities in a regio- and stereoselective manner onto sugar scaffolds represents a substantial challenge. Most of the modern methods of for the preparation of 1-, 2- and 3-amino sugars are those starting from "an active ester" of carbohydrate derivatives, glycals, alcohols, carbonyl compounds and amino acids. A substantial progress in the development of region- and stereoselective methods of amino sugar synthesis has been made in the recent years, due to the application of metal-based catalysts and tethered approaches. A comprehensive review on the current state of knowledge on biosynthesis and chemical synthesis of amino sugars is presented.
Topics: Amino Sugars; Catalysis; Metals; Molecular Structure; Secondary Metabolism; Stereoisomerism; Transaminases
PubMed: 27592039
DOI: 10.1016/j.carres.2016.08.005 -
Advances in Carbohydrate Chemistry and... 2016
Topics: Amino Sugars; Biological Products; Chemistry Techniques, Synthetic; Glucosamine; Glycoconjugates; Glycoside Hydrolases; Glycosides; Glycosylation; Humans; Lysosomal Storage Diseases; Molecular Chaperones; Oligosaccharides; Stevia; Sweetening Agents
PubMed: 27816109
DOI: 10.1016/S0065-2318(16)30013-0 -
Advances in Carbohydrate Chemistry and... 2023Fructosamine has long been considered as a key intermediate of the Maillard reaction, which to a large extent is responsible for specific aroma, taste, and color...
Fructosamine has long been considered as a key intermediate of the Maillard reaction, which to a large extent is responsible for specific aroma, taste, and color formation in thermally processed or dehydrated foods. Since the 1980s, however, as a product of the Amadori rearrangement reaction between glucose and biologically significant amines such as proteins, fructosamine has experienced a boom in biomedical research, mainly due to its relevance to pathologies in diabetes and aging. In this chapter, we assess the scope of the knowledge on and applications of fructosamine-related molecules in chemistry, food, and health sciences, as reflected mostly in publications within the past decade. Methods of fructosamine synthesis and analysis, its chemical, and biological properties, and degradation reactions, together with fructosamine-modifying and -recognizing proteins are surveyed.
Topics: Humans; Fructosamine; Fructose; Maillard Reaction; Proteins; Diabetes Mellitus
PubMed: 37968038
DOI: 10.1016/bs.accb.2023.10.002 -
Biomedicine & Pharmacotherapy =... Nov 2017Glucosamine is an amino sugar that is produced naturally in human body. It is an essential carbohydrate component of many cellular glycoproteins, glycolipids, and... (Review)
Review
Glucosamine is an amino sugar that is produced naturally in human body. It is an essential carbohydrate component of many cellular glycoproteins, glycolipids, and glycosaminoglycans (GAGs). This popular over-the-counter supplement is also found in the exoskeleton of crustaceans. Glucosamine and its derivatives have a long history in medicine for inflammatory conditions specially to relieve arthritis. This dietary supplement has numerous biological and pharmacological properties, including anti-inflammatory, antioxidant, anti-aging, anti-fibrotic, neuroprotective and cardioprotective activities. Many studies have shown that glucosamine has anti-cancer activity through influence on biological pathways involved in cell death, apoptosis, cell proliferation, and angiogenesis. Accordingly, this comprehensive review summarizes anti-cancer molecular mechanisms of glucosamine in details.
Topics: Animals; Antineoplastic Agents; Autophagy; Glucosamine; Humans; Models, Biological; Signal Transduction
PubMed: 28922722
DOI: 10.1016/j.biopha.2017.08.122 -
The Journal of Biological Chemistry Apr 2022Nucleotide sugar (NS) dehydratases play a central role in the biosynthesis of deoxy and amino sugars, which are involved in a variety of biological functions in all... (Review)
Review
Nucleotide sugar (NS) dehydratases play a central role in the biosynthesis of deoxy and amino sugars, which are involved in a variety of biological functions in all domains of life. Bacteria are true masters of deoxy sugar biosynthesis as they can produce a wide range of highly specialized monosaccharides. Indeed, deoxy and amino sugars play important roles in the virulence of gram-positive and gram-negative pathogenic species and are additionally involved in the biosynthesis of diverse macrolide antibiotics. The biosynthesis of deoxy sugars relies on the activity of NS dehydratases, which can be subdivided into three groups based on their structure and reaction mechanism. The best-characterized NS dehydratases are the 4,6-dehydratases that, together with the 5,6-dehydratases, belong to the NS-short-chain dehydrogenase/reductase superfamily. The other two groups are the less abundant 2,3-dehydratases that belong to the Nudix hydrolase superfamily and 3-dehydratases, which are related to aspartame aminotransferases. 4,6-Dehydratases catalyze the first step in all deoxy sugar biosynthesis pathways, converting nucleoside diphosphate hexoses to nucleoside diphosphate-4-keto-6-deoxy hexoses, which in turn are further deoxygenated by the 2,3- and 3-dehydratases to form dideoxy and trideoxy sugars. In this review, we give an overview of the NS dehydratases focusing on the comparison of their structure and reaction mechanisms, thereby highlighting common features, and investigating differences between closely related members of the same superfamilies.
Topics: Hydro-Lyases; Nucleosides; Nucleotides; Substrate Specificity; Sugars
PubMed: 35271853
DOI: 10.1016/j.jbc.2022.101809 -
Advances in Carbohydrate Chemistry and... 2018
Topics: Animals; Humans; N-Acetylneuraminic Acid
PubMed: 30509402
DOI: 10.1016/S0065-2318(18)30014-3