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Physical Chemistry Chemical Physics :... Aug 2023Determining carbohydrate structures, such as their compositions, linkage positions, and in particular the anomers and stereoisomers, is a great challenge. Isomers of...
Determining carbohydrate structures, such as their compositions, linkage positions, and in particular the anomers and stereoisomers, is a great challenge. Isomers of different anomers or stereoisomers have the same sequences of chemical bonds, but have different orientations of some chemical bonds which are difficult to be distinguished by mass spectrometry. Collision-induced dissociation (CID) tandem mass spectroscopy (MS/MS) is a widely used technique for characterizing carbohydrate structures. Understanding the carbohydrate dissociation mechanism is important for obtaining the structural information from MS/MS. In this work, we studied the CID mechanism of galactose--acetylgalactosamine (Gal-GalNAc) and glucose--acetylglucosamine (Glc-GlcNAc) disaccharides with 1→3 and 1→4 linkages. For Gal-GalNAc disaccharides, the CID mass spectra of sodium ion adducts show significant difference between the α- and β-anomers of GalNAc at the reducing end, while no difference in the CID mass spectra between two anomers of Glc-GlcNAc disaccharides was found. Quantum chemistry calculations show that for Gal-GalNAc disaccharides, the difference of the dissociation barriers between dehydration and glycosidic bond cleavage is significantly small in the β-anomer compared to that in the α-anomer; while these differences are similar between the α- and β-anomers of Glc-GlcNAc disaccharides. These differences can be attributed to the different orientations of hydroxyl and -acetyl groups located at GalNAc and GlcNAc. The calculation results are consistent with the CID spectra of isotope labelled disaccharides. Our study provides an insight into the CID of 1→3 and 1→4 linked Gal-GalNAc and Glc-GlcNAc disaccharides. This information is useful for determining the anomeric configurations of GalNAc in oligosaccharides.
Topics: Disaccharides; Tandem Mass Spectrometry; Oligosaccharides; Carbohydrates; Glucose
PubMed: 37565323
DOI: 10.1039/d3cp02530f -
Journal of Chromatography. A Aug 2022Heparin is a linear sulfated polysaccharide with a complex structure. It is important to figure out the sequences at the terminals of the sugar chains, as it will help...
Heparin is a linear sulfated polysaccharide with a complex structure. It is important to figure out the sequences at the terminals of the sugar chains, as it will help us understand the heparin structure deeper and control its quality properly. The tetrasaccharide linkage region (LR) could be a tag to help us find out heparin terminals after digestion by different combinations of heparinases. In this work, orthogonal chromatographic approaches including SAX, SEC-MS and 2D-LC-MS were applied to qualitatively and quantitatively analyze the heparinase released LR-terminals. The disaccharides next to LR are those ones with low or non-sulfation, UA-GlcNAc and UA-GlcNAc6S, and then they are extended with the highly sulfated disaccharides, IdoA2S-GlcNS and IdoA2S-GlcNS6S. It is suggested that the sulfo transferases did not work at the sugar residues next to LR terminal, especially the 2-O-sulfo and N-sulfo transferases, which could be affected by steric hindrance from LR, when heparin is biosynthesized. This conclusion will be theoretical fundamental to help us understand heparin's structure deeper. The methods provided in this work could be potential ways to control heparin's quality and monitor the production processes of heparin properly.
Topics: Disaccharides; Heparin; Heparin Lyase; Oligosaccharides; Transferases
PubMed: 35853422
DOI: 10.1016/j.chroma.2022.463318 -
ACS Synthetic Biology Sep 2023Flavonoids are an essential class of secondary metabolites found in plants and possess various nutritional, medicinal, and agricultural properties. However, the poor...
Flavonoids are an essential class of secondary metabolites found in plants and possess various nutritional, medicinal, and agricultural properties. However, the poor water solubility of flavonoid aglycones limits their potential applications. To overcome this issue, glycosylation is a promising approach for improving water solubility and bioavailability. In this study, we constructed a flavonoid-7--disaccharide biosynthetic pathway with flavonoid aglycones as substrates in . Subsequently, through metabolic engineering and promoter strategies, we constructed a UDP-rhamnose regeneration system and optimized the UDP-glucose (UDPG) synthetic pathway. The optimized strain produced up to 131.3 mg/L eriocitrin. After this, the chassis cells were applied to other flavonoids, with substrates such as (2)-naringenin, (2)-hesperetin, diosmetin, and (2)-eriodictyol, which resulted in the synthesis of 179.9 mg/L naringin, 276.6 mg/L hesperidin, 249.0 mg/L neohesperidin, 30.4 mg/L diosmin, and 100.7 mg/L neoeriocitrin. To the best of our knowledge, this is the first report on the biosynthesis of flavonoid-7--disaccharide.
Topics: Saccharomyces cerevisiae; Flavonoids; Glycosylation; Disaccharides; Water; Metabolic Engineering
PubMed: 37566738
DOI: 10.1021/acssynbio.3c00348 -
Journal of Gastroenterology and... Aug 2021Low fermentable oligosaccharide, disaccharide, monosaccharide, and polyol (FODMAP) diet improves irritable bowel syndrome (IBS) symptoms. Data on long-term "modified"... (Randomized Controlled Trial)
Randomized Controlled Trial
Low fermentable oligosaccharide, disaccharide, monosaccharide, and polyol diet in patients with diarrhea-predominant irritable bowel syndrome: A prospective, randomized trial.
BACKGROUND AND AIM
Low fermentable oligosaccharide, disaccharide, monosaccharide, and polyol (FODMAP) diet improves irritable bowel syndrome (IBS) symptoms. Data on long-term "modified" FODMAP diet are emerging. We aimed to assess efficacy and acceptability of short-term "strict" low FODMAP diet (LFD) and long-term "modified" FODMAP diet in patients with diarrhea-predominant IBS (IBS-D).
METHODS
This prospective randomized trial included patients with IBS-D (Rome IV) and IBS severity scoring system (IBS-SSS) ≥ 175. In phase I (4 weeks), patients were randomized to strict LFD and traditional dietary advice (TDA) groups. From 4 to 16 weeks, LFD group was advised systematic reintroduction of FODMAPs ("modified" FODMAP diet). Response was defined as > 50-point reduction in IBS-SSS.
RESULTS
Of the total 166 patients with IBS-D screened, 101 (mean age 41.9 ± 17.1 years, 58% male) were randomized to LFD (n = 52) and TDA (n = 49) groups. Both at 4 and 16 weeks, total IBS-SSS and IBS quality of life score reduced significantly in both groups, but there was significantly greater reduction in LFD group. By intention-to-treat analysis, responders in LFD group were significantly higher than TDA group (4 weeks-62.7% [32/51] vs 40.8% [20/49], respectively, P = 0.0448; 16 weeks-52.9% [27/51] vs 30.6% [15/49], respectively; P = 0.0274). Compliance to LFD was 93% at 4 weeks and 64% at 16 weeks. Energy, carbohydrate, fat, and fiber intake showed reduction in LFD group at 4 weeks, which improved till 16 weeks.
CONCLUSIONS
Strict LFD for short-term and "modified" LFD for long term in IBS-D patients is acceptable and leads to significant improvement in symptoms and quality of life.
Topics: Adult; Diarrhea; Diet; Diet, Carbohydrate-Restricted; Disaccharides; Female; Fermentation; Humans; Irritable Bowel Syndrome; Male; Middle Aged; Monosaccharides; Oligosaccharides; Polymers; Prospective Studies; Quality of Life; Young Adult
PubMed: 33464683
DOI: 10.1111/jgh.15410 -
Analytical and Bioanalytical Chemistry Nov 2021Chondroitin sulfate (CS) glycosaminoglycans are biologically active sulfated polysaccharides that pose an analytical challenge for their structural analysis and...
Chondroitin sulfate (CS) glycosaminoglycans are biologically active sulfated polysaccharides that pose an analytical challenge for their structural analysis and functional evaluation. In this study, we developed a hydrophilic interaction liquid chromatography separation method and its on-line coupling to mass spectrometry (MS) allowing efficient differentiation and sensitive detection of mono-, di-, and trisulfated CS disaccharides and their positional isomers, without requiring prior derivatization. The composition of the mobile phase in terms of pH and concentration showed great influence on the chromatographic separation and was varied to allow the distinction of each CS without signal overlap for a total analysis time of 25 min. This methodology was applied to determine the disaccharide composition of biological reaction media resulting from various enzymatic transformations of CS, such as enzymatic desulfation of CS disaccharides by a CS 4-O-endosulfatase, and depolymerization of the CS endocan by chondroitinase lyase ABC.
Topics: Chondroitin Sulfates; Chromatography, Liquid; Disaccharides; Hydrogen-Ion Concentration; Hydrophobic and Hydrophilic Interactions; Isomerism; Spectrometry, Mass, Electrospray Ionization; Sulfates; Tandem Mass Spectrometry; Temperature
PubMed: 34651208
DOI: 10.1007/s00216-021-03679-9 -
Expert Opinion on Drug Delivery Mar 2015Many therapeutics have issues with delivery due to nonoptimal pharmacokinetics and/or detrimental side effects due to their nonhuman nature. Injectable biologic drugs...
Many therapeutics have issues with delivery due to nonoptimal pharmacokinetics and/or detrimental side effects due to their nonhuman nature. Injectable biologic drugs are one class that often needs assistance. The pharma industry has employed a variety of delivery strategies and this Editorial focuses on drug-polymer conjugates, in particular those utilizing a newly introduced system using a natural carbohydrate called heparosan. This molecule, the biosynthetic precursor to the well-known drug heparin, appears tolerated due to its 'self' nature as well as exhibits intrinsically favorable behavior in the bloodstream and tissues. The polysaccharide is stable in the extracellular spaces of mammals, but degraded by lysosomal enzymes following entry into the cell. Heparosan manufacture utilizes a novel synchronized, stoichiometrically controlled reaction employing a sugar-polymerizing enzyme in an aqueous buffer system that results in a quasi-monodisperse product. Heparosan is predicted to serve as a conjugating vehicle to extend the plasma half-life of biologics without liabilities of polydispersity, immunogenicity and/or unwanted accumulation in the body that are observed for other types of polymer such as PEG, hydroxyethyl starch, or poly(sialic acid).
Topics: Chemistry, Pharmaceutical; Disaccharides; Drug Delivery Systems; Excipients; Injections
PubMed: 25363378
DOI: 10.1517/17425247.2015.978282 -
The Journal of Physical Chemistry. B Oct 2021The structure and conformation of glycosaminoglycans (GAGs) are of central importance to understand the mechanisms behind their functions in biological systems. Due to...
The structure and conformation of glycosaminoglycans (GAGs) are of central importance to understand the mechanisms behind their functions in biological systems. Due to the inherent chemical and structural heterogeneity of GAGs, focusing on longer, naturally existing GAG chains hinders drawing conclusions on the influence of the chemical functionalization on the basic conformational degree of freedom, that is, the dynamic shape of glycosidic linkage present in the particular disaccharide repeating unit. In the present study, we have considered the complete set of 106 GAG-related disaccharides, being potential building blocks for longer GAG chains (including hyaluronan, chondroitin, keratan, dermatan, and heparan). Both the unfunctionalized units and all possible combinations of either partially or fully sulfated derivatives contribute to this number. The unbiased and enhanced sampling molecular dynamics simulations provide a link to understand the influence of sulfation on the conformational properties of GAG glycosidic linkages. Residue-residue hydrogen bonding is not significant for either the glycosidic linkage conformation or its flexibility. It was found that in the majority of cases, the dominating conformation of the linkage is weakly affected by sulfation and the main role is played by the steric and stereoelectronic effects. However, there exist numerous cases where sulfation increases the contribution of alternative conformations to a nonnegligible extent and, in some rare cases (restricted to disaccharides building heparan), leads to the reorientation of the glycosidic linkage. The identified sulfation sites, being the most important in this context, are C and C at the GlcNAc residue. Finally, the full set of free energy maps relying on the glycosidic dihedral angle values for diverse GAG disaccharides are provided; they may be used for further studies, focused on longer GAG chains.
Topics: Disaccharides; Glycosaminoglycans; Hyaluronic Acid; Molecular Conformation; Molecular Dynamics Simulation
PubMed: 34550710
DOI: 10.1021/acs.jpcb.1c04860 -
Carbohydrate Polymers Dec 2023Fucosylated chondroitin sulfate (FCS) extracted from Phyllophorella kohkutiensis (PkFCS) is composed of d-GalNAc, d-GlcA, l-Fuc and -SO. According to the defined...
Fucosylated chondroitin sulfate (FCS) extracted from Phyllophorella kohkutiensis (PkFCS) is composed of d-GalNAc, d-GlcA, l-Fuc and -SO. According to the defined structures revealed by NMR spectra of the branches released by mild acid hydrolysis and oligosaccharides generated by β-eliminative depolymerization, the backbone of PkFCS is CS-E, and the branch types attached to C-3 of d-GlcA include l-Fuc, l-Fuc, l-Fuc and the disaccharide α-d-GalNAc-1,2-α-l-Fuc with the ratio of 43:13:22:22. Notably, novel heptasaccharide and hendecasaccharide were identified that are branched with continuous distribution of the disaccharide. The structural sequences of the oligosaccharides indicate that three unique structural motifs are present in the entire PkFCS polymer, including a motif branched with randomly distributed different sulfated l-Fuc units, a motif containing regular l-Fuc branches and a motif enriched in α-d-GalNAc-1,2-α-l-Fuc. This is the first report about the distribution pattern of diverse branches in natural FCS. Natural PkFCS exhibited potent anticoagulant activity on APTT prolonging and anti-iXase activity. Regarding the structurally defined oligosaccharides with sulfated fucosyl side chains, octasaccharide (Pk4b) is the minimum fragment responsible for its anticoagulant activity correlated with anti-iXase. However, further glycosyl modification with a non-sulfated d-GalNAc at the C-2 position of l-Fuc could significantly decrease the anticoagulant and anti-iXase activity.
Topics: Animals; Sea Cucumbers; Anticoagulants; Chondroitin Sulfates; Disaccharides; Sulfates; Sulfur Oxides
PubMed: 37739534
DOI: 10.1016/j.carbpol.2023.121304 -
PloS One 2015Trehalose is a naturally occurring disaccharide which is associated with extraordinary stress-tolerance capacity in certain species of unicellular and multicellular...
Trehalose is a naturally occurring disaccharide which is associated with extraordinary stress-tolerance capacity in certain species of unicellular and multicellular organisms. In mammalian cells, presence of intra- and extracellular trehalose has been shown to confer improved tolerance against freezing and desiccation. Since mammalian cells do not synthesize nor import trehalose, the development of novel methods for efficient intracellular delivery of trehalose has been an ongoing investigation. Herein, we studied the membrane permeability of engineered lipophilic derivatives of trehalose. Trehalose conjugated with 6 acetyl groups (trehalose hexaacetate or 6-O-Ac-Tre) demonstrated superior permeability in rat hepatocytes compared with regular trehalose, trehalose diacetate (2-O-Ac-Tre) and trehalose tetraacetate (4-O-Ac-Tre). Once in the cell, intracellular esterases hydrolyzed the 6-O-Ac-Tre molecules, releasing free trehalose into the cytoplasm. The total concentration of intracellular trehalose (plus acetylated variants) reached as high as 10 fold the extracellular concentration of 6-O-Ac-Tre, attaining concentrations suitable for applications in biopreservation. To describe this accumulation phenomenon, a diffusion-reaction model was proposed and the permeability and reaction kinetics of 6-O-Ac-Tre were determined by fitting to experimental data. Further studies suggested that the impact of the loading and the presence of intracellular trehalose on cellular viability and function were negligible. Engineering of trehalose chemical structure rather than manipulating the cell, is an innocuous, cell-friendly method for trehalose delivery, with demonstrated potential for trehalose loading in different types of cells and cell lines, and can facilitate the wide-spread application of trehalose as an intracellular protective agent in biopreservation studies.
Topics: Acetylation; Animals; Cell Membrane Permeability; Cell Survival; Cells, Cultured; Disaccharides; Female; Hepatocytes; Models, Theoretical; Rats; Trehalose
PubMed: 26115179
DOI: 10.1371/journal.pone.0130323 -
Chembiochem : a European Journal of... Jan 2019A general strategy for the diverse synthesis of ten disaccharide aminoglycosides, including natural 2-trehalosamine (1), 3-trehalosamine (2), 4-trehalosamine (3), and...
A general strategy for the diverse synthesis of ten disaccharide aminoglycosides, including natural 2-trehalosamine (1), 3-trehalosamine (2), 4-trehalosamine (3), and neotrehalosyl 3,3'-diamine (8) and synthetic aminoglycosides 4-7, 9, and 10, has been developed. The aminoglycoside compounds feature different anomeric configurations and numbers of amino groups. The key step for the synthesis was the glycosylation coupling of a stereodirecting donor with a configuration-stable TMS glycoside acceptor. Either the donor or acceptor could be substituted with an azido group. The aminoglycosides prepared in the present study were characterized by 1D and 2D NMR spectroscopy.
Topics: Amino Sugars; Aminoglycosides; Biological Products; Carbohydrate Conformation; Disaccharides
PubMed: 30421539
DOI: 10.1002/cbic.201800656