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Topical Collection "Advances in Carbohydrate Chemistry"

A topical collection in Molecules (ISSN 1420-3049). This collection belongs to the section "Molecular Diversity".

Editors

Collection Editor
Dr. Vito Ferro

School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia
Website | E-Mail
Interests: carbohydrate chemistry; medicinal chemistry; heparanase inhibitors; heparan sulfate mimetics
Collection Editor
Dr. Trinidad Velasco-Torrijos

Department of Chemistry, National University of Ireland, Maynooth, Co. Kildare, Ireland
Website | E-Mail
Interests: carbohydrate chemistry; glycoconjugates; glycopeptides; glycolipids; glycomimetics, molecular scaffolds

Topical Collection Information

Dear Colleagues,

Since the launch of the first Special Issue in this journal on Advances in Carbohydrate Chemistry, the field of glycobiology has continued to grow and mature. It is well established that carbohydrates (or glycans) play critical roles in biological systems in both normal physiology and disease. However, a better understanding of the intricate details of carbohydrate–protein interactions is the key to unlocking the enormous potential of glycans and glycomimetics for the development of new therapeutics, vaccines and diagnostics. Carbohydrate chemists can continue to play an important role in advancing our understanding of glycobiology by providing the required synthetic access to pure, well-defined carbohydrates and glycoconjugates for biological studies, although many challenges still remain. In addition, carbohydrates and glycomimetics have potential applications in many areas of biomedical research and drug development. Finally, carbohydrates remain an excellent source of building blocks for chiral pool syntheses and as raw materials for the development of biotechnologically derived commodity chemicals.

We invite our colleagues to submit research articles and comprehensive reviews addressing the above mentioned topics, and on recent advances in carbohydrate chemistry in general, for publication in this Special Issue.

Dr. Vito Ferro
Dr. Trinidad Velasco-Torrijos
Collection 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 collection 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. Molecules 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 1800 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

  • carbohydrate chemistry
  • glycoconjugates
  • glycopeptides
  • glycolipids
  • glycomimetics
  • molecular scaffolds
  • sustainable carbohydrate raw materials
  • carbohydrate nanostructures
  • bioactive compounds

Related Special Issue

Published Papers (29 papers)

2016

Jump to: 2015, 2014, 2013, 2012

Open AccessArticle Investigating Glycol-Split-Heparin-Derived Inhibitors of Heparanase: A Study of Synthetic Trisaccharides
Molecules 2016, 21(11), 1602; doi:10.3390/molecules21111602
Received: 25 October 2016 / Revised: 16 November 2016 / Accepted: 18 November 2016 / Published: 23 November 2016
Cited by 1 | PDF Full-text (1951 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Heparanase is the only known endoglycosidase able to cleave heparan sulfate. Roneparstat and necuparanib, heparanase inhibitors obtained from heparin and currently being tested in man as a potential drugs against cancer, contain in their structure glycol-split uronic acid moieties probably responsible for their
[...] Read more.
Heparanase is the only known endoglycosidase able to cleave heparan sulfate. Roneparstat and necuparanib, heparanase inhibitors obtained from heparin and currently being tested in man as a potential drugs against cancer, contain in their structure glycol-split uronic acid moieties probably responsible for their strong inhibitory activity. We describe here the total chemical synthesis of the trisaccharide GlcNS6S-GlcA-1,6anGlcNS (1) and its glycol-split (gs) counterpart GlcNS6S-gsGlcA-1,6anGlcNS (2) from glucose. As expected, in a heparanase inhibition assay, compound 2 is one order of magnitude more potent than 1. Using molecular modeling techniques we have created a 3D model of 1 and 2 that has been validated by NOESY NMR experiments. The pure synthetic oligosaccharides have allowed the first in depth study of the conformation of a glycol-split glucuronic acid. Introducing a glycol-split unit in the structure of 1 increases the conformational flexibility and shortens the distance between the two glucosamine motives, thus promoting interaction with heparanase. However, comparing the relative activities of 2 and roneparstat, we can conclude that the glycol-split motive is not the only determinant of the strong inhibitory effect of roneparstat. Full article
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Figure 1

Open AccessReview Influenza Neuraminidase Inhibitors: Synthetic Approaches, Derivatives and Biological Activity
Molecules 2016, 21(11), 1513; doi:10.3390/molecules21111513
Received: 17 October 2016 / Revised: 2 November 2016 / Accepted: 3 November 2016 / Published: 11 November 2016
Cited by 4 | PDF Full-text (12236 KB) | HTML Full-text | XML Full-text
Abstract
Despite being a common viral disease, influenza has very negative consequences, causing the death of around half a million people each year. A neuraminidase located on the surface of the virus plays an important role in viral reproduction by contributing to the release
[...] Read more.
Despite being a common viral disease, influenza has very negative consequences, causing the death of around half a million people each year. A neuraminidase located on the surface of the virus plays an important role in viral reproduction by contributing to the release of viruses from infected host cells. The treatment of influenza is mainly based on the administration of neuraminidase inhibitors. The neuraminidase inhibitors zanamivir, laninamivir, oseltamivir and peramivir have been commercialized and have been demonstrated to be potent influenza viral neuraminidase inhibitors against most influenza strains. In order to create more potent neuraminidase inhibitors and fight against the surge in resistance resulting from naturally-occurring mutations, these anti-influenza drugs have been used as templates for the development of new neuraminidase inhibitors through structure-activity relationship studies. Here, we review the synthetic routes to these commercial drugs, the modifications which have been performed on these structures and the effects of these modifications on their inhibitory activity. Full article
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Open AccessArticle A Modular Synthetic Approach to Isosteric Sulfonic Acid Analogues of the Anticoagulant Pentasaccharide Idraparinux
Molecules 2016, 21(11), 1497; doi:10.3390/molecules21111497
Received: 7 September 2016 / Revised: 1 November 2016 / Accepted: 3 November 2016 / Published: 11 November 2016
PDF Full-text (1267 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Heparin-based anticoagulants are drugs of choice in the therapy and prophylaxis of thromboembolic diseases. Idraparinux is a synthetic anticoagulant pentasaccharide based on the heparin antithrombin-binding domain. In the frame of our ongoing research aimed at the synthesis of sulfonic acid-containing heparinoid anticoagulants, we
[...] Read more.
Heparin-based anticoagulants are drugs of choice in the therapy and prophylaxis of thromboembolic diseases. Idraparinux is a synthetic anticoagulant pentasaccharide based on the heparin antithrombin-binding domain. In the frame of our ongoing research aimed at the synthesis of sulfonic acid-containing heparinoid anticoagulants, we elaborated a modular pathway to obtain a series of idraparinux-analogue pentasaccharides bearing one or two primary sulfonic acid moieties. Five protected pentasaccharides with different C-sulfonation patterns were prepared by two subsequent glycosylation reactions, respectively, using two monosaccharide and four disaccharide building blocks. Transformation of the protected derivatives into the fully O-sulfated, O-methylated sulfonic acid end-products was also studied. Full article
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Figure 1

Open AccessArticle Agavins Increase Neurotrophic Factors and Decrease Oxidative Stress in the Brains of High-Fat Diet-Induced Obese Mice
Molecules 2016, 21(8), 998; doi:10.3390/molecules21080998
Received: 12 April 2016 / Revised: 18 July 2016 / Accepted: 26 July 2016 / Published: 2 August 2016
PDF Full-text (2014 KB) | HTML Full-text | XML Full-text
Abstract
Background: Fructans obtained from agave, called agavins, have recently shown significant benefits for human health including obesity. Therefore, we evaluated the potential of agavins as neuroprotectors and antioxidants by determining their effect on brain-derived neurotrophic factor (BDNF) and glial-derived neurotrophic factor (GDNF) as
[...] Read more.
Background: Fructans obtained from agave, called agavins, have recently shown significant benefits for human health including obesity. Therefore, we evaluated the potential of agavins as neuroprotectors and antioxidants by determining their effect on brain-derived neurotrophic factor (BDNF) and glial-derived neurotrophic factor (GDNF) as well as oxidative brain damage in of obese mice. Methods: Male C57BL/6J mice were fed a high-fat diet (HFD) and treated daily with 5% (HFD/A5) or 10% (HFD/A10) of agavins or a standard diet (SD) for 10 weeks. The levels of BDNF and GDNF were evaluated by ELISA. The oxidative stress was evaluated by lipid peroxidation (TBARS) and carbonyls. SCFAs were also measured with GC-FID. Differences between groups were assessed using ANOVA and by Tukey’s test considering p < 0.05. Results: The body weight gain and food intake of mice HFD/A10 group were significantly lower than those in the HFD group. Agavins restored BDNF levels in HFD/A5 group and GDNF levels of HFD/A5 and HFD/A10 groups in cerebellum. Interestingly, agavins decreased TBARS levels in HFD/A5 and HFD/A10 groups in the hippocampus, frontal cortex and cerebellum. Carbonyl levels were also lower in HFD/A5 and HFD/A10 for only the hippocampus and cerebellum. It was also found that agavins enhanced SCFAs production in feces. Conclusion: Agavins may act as bioactive ingredients with antioxidant and protective roles in the brain. Full article
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Open AccessReview Multivalent Carbohydrate-Lectin Interactions: How Synthetic Chemistry Enables Insights into Nanometric Recognition
Molecules 2016, 21(5), 629; doi:10.3390/molecules21050629
Received: 7 April 2016 / Revised: 2 May 2016 / Accepted: 10 May 2016 / Published: 13 May 2016
Cited by 19 | PDF Full-text (11736 KB) | HTML Full-text | XML Full-text
Abstract
Glycan recognition by sugar receptors (lectins) is intimately involved in many aspects of cell physiology. However, the factors explaining the exquisite selectivity of their functional pairing are not yet fully understood. Studies toward this aim will also help appraise the potential for lectin-directed
[...] Read more.
Glycan recognition by sugar receptors (lectins) is intimately involved in many aspects of cell physiology. However, the factors explaining the exquisite selectivity of their functional pairing are not yet fully understood. Studies toward this aim will also help appraise the potential for lectin-directed drug design. With the network of adhesion/growth-regulatory galectins as therapeutic targets, the strategy to recruit synthetic chemistry to systematically elucidate structure-activity relationships is outlined, from monovalent compounds to glyco-clusters and glycodendrimers to biomimetic surfaces. The versatility of the synthetic procedures enables to take examining structural and spatial parameters, alone and in combination, to its limits, for example with the aim to produce inhibitors for distinct galectin(s) that exhibit minimal reactivity to other members of this group. Shaping spatial architectures similar to glycoconjugate aggregates, microdomains or vesicles provides attractive tools to disclose the often still hidden significance of nanometric aspects of the different modes of lectin design (sequence divergence at the lectin site, differences of spatial type of lectin-site presentation). Of note, testing the effectors alone or in combination simulating (patho)physiological conditions, is sure to bring about new insights into the cooperation between lectins and the regulation of their activity. Full article
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Open AccessArticle Efficient Synthesis of the Lewis A Tandem Repeat
Molecules 2016, 21(5), 614; doi:10.3390/molecules21050614
Received: 11 April 2016 / Revised: 4 May 2016 / Accepted: 6 May 2016 / Published: 11 May 2016
PDF Full-text (4488 KB) | HTML Full-text | XML Full-text
Abstract
The convergent synthesis of the Lewis A (Lea) tandem repeat is described. The Lea tandem repeat is a carbohydrate ligand for a mannose binding protein that shows potent inhibitory activity against carcinoma growth. The Lea unit, {β-d-Gal-(1→3)-[α-
[...] Read more.
The convergent synthesis of the Lewis A (Lea) tandem repeat is described. The Lea tandem repeat is a carbohydrate ligand for a mannose binding protein that shows potent inhibitory activity against carcinoma growth. The Lea unit, {β-d-Gal-(1→3)-[α-l-Fuc-(1→4)]-β-d-GlcNAc}, was synthesized by stereoselective nitrile-assisted β-galactosylation with the phenyl 3-O-allyl-2,4,6-tri-O-benzyl-1-thio-β-galactoside, and ether-assisted α-fucosylation with fucosyl (N-phenyl)trifluoroacetimidate. This common Lea unit was easily converted to an acceptor and donor in high yields, and the stereoselective assembly of the hexasaccharide and dodecasaccharide as the Lea tandem repeat framework was achieved by 2-trichloroacetamido-assisted β-glycosylation and the (N-phenyl)trifluoroacetimidate method. Full article
Open AccessReview Polysaccharides from the Marine Environment with Pharmacological, Cosmeceutical and Nutraceutical Potential
Molecules 2016, 21(5), 551; doi:10.3390/molecules21050551
Received: 15 March 2016 / Revised: 18 April 2016 / Accepted: 22 April 2016 / Published: 27 April 2016
Cited by 10 | PDF Full-text (1058 KB) | HTML Full-text | XML Full-text
Abstract
Carbohydrates, also called saccharides, are molecules composed of carbon, hydrogen, and oxygen. They are the most abundant biomolecules and essential components of many natural products and have attracted the attention of researchers because of their numerous human health benefits. Among carbohydrates the polysaccharides
[...] Read more.
Carbohydrates, also called saccharides, are molecules composed of carbon, hydrogen, and oxygen. They are the most abundant biomolecules and essential components of many natural products and have attracted the attention of researchers because of their numerous human health benefits. Among carbohydrates the polysaccharides represent some of the most abundant bioactive substances in marine organisms. In fact, many marine macro- and microorganisms are good resources of carbohydrates with diverse applications due to their biofunctional properties. By acting on cell proliferation and cycle, and by modulating different metabolic pathways, marine polysaccharides (including mainly chitin, chitosan, fucoidan, carrageenan and alginate) also have numerous pharmaceutical activities, such as antioxidative, antibacterial, antiviral, immuno-stimulatory, anticoagulant and anticancer effects. Moreover, these polysaccharides have many general beneficial effects for human health, and have therefore been developed into potential cosmeceuticals and nutraceuticals. In this review we describe current advances in the development of marine polysaccharides for nutraceutical, cosmeceutical and pharmacological applications. Research in this field is opening new doors for harnessing the potential of marine natural products. Full article

2015

Jump to: 2016, 2014, 2013, 2012

Open AccessArticle An Unusual Carbohydrate Conformation is Evident in Moraxella catarrhalis Oligosaccharides
Molecules 2015, 20(8), 14234-14253; doi:10.3390/molecules200814234
Received: 23 May 2015 / Revised: 24 July 2015 / Accepted: 27 July 2015 / Published: 5 August 2015
Cited by 3 | PDF Full-text (3093 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Oligosaccharide structures derived from the lipooligosaccharide of M. catarrhalis show that the highly branched glucose-rich inner core of the oligosaccharide has an altered conformation compared to the most truncated tetra-glucose-Kdo lgt1/4Δ oligosaccharide structure. Addition of one residue each to the (1-4) and (1-6)
[...] Read more.
Oligosaccharide structures derived from the lipooligosaccharide of M. catarrhalis show that the highly branched glucose-rich inner core of the oligosaccharide has an altered conformation compared to the most truncated tetra-glucose-Kdo lgt1/4Δ oligosaccharide structure. Addition of one residue each to the (1-4) and (1-6) chains to give the lgt2Δ oligosaccharide is the minimum requirement for this conformational change to occur. Extensive molecular modeling and NMR investigations have shown that the (1-3), (1-4), and (1-6) glycosidic linkages from the central α-D-Glcp have significantly altered conformational preferences between the two structures. For the lgt1/4Δ oligosaccharide the (1-3) and (1-4) linkage populates predominantly the syn minimum on the conformational free energy map and for the (1-6) linkage conformational flexibility is observed, which is supported by 1H-NMR T1 measurements. For the lgt2Δ oligosaccharide the unusual “(1-4)anti-ψ(1-6)gg” conformation, which could be confirmed by long-range NOE signals, is a dominant conformation in which the oligosaccharide is very compact with the terminal α-D-GlcNAc residue folding back towards the center of the molecule leading to an extensive intra-molecular hydrophobic interaction between the terminal residues. Comparing effective H-H distances, which were calculated for conformational sub-ensembles, with the NOE distances revealed that typically multiple conformations could be present without significantly violating the measured NOE restraints. For lgt2Δ the presence of more than one conformation is supported by the NOE data. Full article
Open AccessReview A Survey of Recent Synthetic Applications of 2,3-Dideoxy-Hex-2-enopyranosides
Molecules 2015, 20(5), 8357-8394; doi:10.3390/molecules20058357
Received: 16 April 2015 / Revised: 4 May 2015 / Accepted: 5 May 2015 / Published: 8 May 2015
Cited by 4 | PDF Full-text (993 KB) | HTML Full-text | XML Full-text
Abstract
Unsaturated carbohydrate derivatives are useful intermediates in synthetic transformations leading to a variety of compounds. The aim of this review is to highlight the rich chemistry of ∆-2,3 unsaturated pyranosides, emphasizing the variety of transformations that have been carried out in these substrates
[...] Read more.
Unsaturated carbohydrate derivatives are useful intermediates in synthetic transformations leading to a variety of compounds. The aim of this review is to highlight the rich chemistry of ∆-2,3 unsaturated pyranosides, emphasizing the variety of transformations that have been carried out in these substrates during the last decade. Full article
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Open AccessArticle Accumulation of GD1α Ganglioside in MDA-MB-231 Breast Cancer Cells Expressing ST6GalNAc V
Molecules 2015, 20(4), 6913-6924; doi:10.3390/molecules20046913
Received: 14 January 2015 / Revised: 9 April 2015 / Accepted: 14 April 2015 / Published: 16 April 2015
Cited by 4 | PDF Full-text (3807 KB) | HTML Full-text | XML Full-text
Abstract
α-Series gangliosides define a particular sub-class of glycosphingolipids containing sialic acid α2,6-linked to GalNAc residue that was isolated as a minor compound from the brain. The sialyltransferase ST6GalNAc V was cloned from mouse brain and showed α2,6-sialyltransferase activity almost exclusively for GM1b
[...] Read more.
α-Series gangliosides define a particular sub-class of glycosphingolipids containing sialic acid α2,6-linked to GalNAc residue that was isolated as a minor compound from the brain. The sialyltransferase ST6GalNAc V was cloned from mouse brain and showed α2,6-sialyltransferase activity almost exclusively for GM1b, to form GD1α and is considered as the main enzyme involved in the biosynthesis of α-series gangliosides. Recently, ST6GALNAC5 was identified as one of the genes over-expressed in breast cancer cell populations selected for their ability to produce brain metastasis. However, the capacity of human breast cancer cells to produce α-series gangliosides has never been clearly demonstrated. Here, we show by stable transfection and MS-MS analysis of total glycosphingolipids that ST6GALNAC5 expressing MDA-MB-231 breast cancer cells accumulate GD1α ganglioside (IV3Neu5Ac1, III6Neu5Ac1Gg4-Cer). Full article
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Open AccessArticle Characterization at 25 °C of Sodium Hyaluronate in Aqueous Solutions Obtained by Transport Techniques
Molecules 2015, 20(4), 5812-5824; doi:10.3390/molecules20045812
Received: 9 January 2015 / Revised: 23 March 2015 / Accepted: 26 March 2015 / Published: 2 April 2015
Cited by 1 | PDF Full-text (851 KB) | HTML Full-text | XML Full-text
Abstract
Mutual diffusion coefficients, D, were determined for aqueous solutions of sodium hyaluronate (NaHy) at 25 °C and concentrations ranging from 0.00 to 1.00 g·dm−3 using the Taylor dispersion technique. From these experimental data, it was possible to estimate some parameters, such
[...] Read more.
Mutual diffusion coefficients, D, were determined for aqueous solutions of sodium hyaluronate (NaHy) at 25 °C and concentrations ranging from 0.00 to 1.00 g·dm−3 using the Taylor dispersion technique. From these experimental data, it was possible to estimate some parameters, such as the hydrodynamic radius Rh, and the diffusion coefficient at infinitesimal concentration, D0, of hyaluronate ion, permitting us to have a better understanding of the structure of these systems of sodium hyaluronate in aqueous solutions. The additional viscosity measurements were done and Huggins constant, kH, and limiting viscosity number, [η], were computed for interaction NaHy/water and NaHy/NaHy determination. Full article
Open AccessArticle Targeting N-Glycan Cryptic Sugar Moieties for Broad-Spectrum Virus Neutralization: Progress in Identifying Conserved Molecular Targets in Viruses of Distinct Phylogenetic Origins
Molecules 2015, 20(3), 4610-4622; doi:10.3390/molecules20034610
Received: 20 January 2015 / Revised: 26 February 2015 / Accepted: 9 March 2015 / Published: 12 March 2015
PDF Full-text (3624 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Identifying molecular targets for eliciting broadly virus-neutralizing antibodies is one of the key steps toward development of vaccines against emerging viral pathogens. Owing to genomic and somatic diversities among viral species, identifying protein targets for broad-spectrum virus neutralization is highly challenging even for
[...] Read more.
Identifying molecular targets for eliciting broadly virus-neutralizing antibodies is one of the key steps toward development of vaccines against emerging viral pathogens. Owing to genomic and somatic diversities among viral species, identifying protein targets for broad-spectrum virus neutralization is highly challenging even for the same virus, such as HIV-1. However, viruses rely on host glycosylation machineries to synthesize and express glycans and, thereby, may display common carbohydrate moieties. Thus, exploring glycan-binding profiles of broad-spectrum virus-neutralizing agents may provide key information to uncover the carbohydrate-based virus-neutralizing epitopes. In this study, we characterized two broadly HIV-neutralizing agents, human monoclonal antibody 2G12 and Galanthus nivalis lectin (GNA), for their viral targeting activities. Although these agents were known to be specific for oligomannosyl antigens, they differ strikingly in virus-binding activities. The former is HIV-1 specific; the latter is broadly reactive and is able to neutralize viruses of distinct phylogenetic origins, such as HIV-1, severe acute respiratory syndrome coronavirus (SARS-CoV), and human cytomegalovirus (HCMV). In carbohydrate microarray analyses, we explored the molecular basis underlying the striking differences in the spectrum of anti-virus activities of the two probes. Unlike 2G12, which is strictly specific for the high-density Man9GlcNAc2Asn (Man9)-clusters, GNA recognizes a number of N-glycan cryptic sugar moieties. These include not only the known oligomannosyl antigens but also previously unrecognized tri-antennary or multi-valent GlcNAc-terminating N-glycan epitopes (Tri/m-Gn). These findings highlight the potential of N-glycan cryptic sugar moieties as conserved targets for broad-spectrum virus neutralization and suggest the GNA-model of glycan-binding warrants focused investigation. Full article
Open AccessArticle Purification and Characterization of Chitinases from Ridgetail White Prawn Exopalaemon carinicauda
Molecules 2015, 20(2), 1955-1967; doi:10.3390/molecules20021955
Received: 17 December 2014 / Accepted: 19 January 2015 / Published: 26 January 2015
Cited by 4 | PDF Full-text (7722 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, we purified two native chitinases from the hepatopancreas of the ridgetail white prawn Exopalaemon carinicauda by using ion-exchange resin chromatography (IEC) and gel filtration. These two chitinases, named EcChi1 and EcChi2, were identified by chitinolytic activity assay and LC-ESI-MS/MS. Their
[...] Read more.
In this paper, we purified two native chitinases from the hepatopancreas of the ridgetail white prawn Exopalaemon carinicauda by using ion-exchange resin chromatography (IEC) and gel filtration. These two chitinases, named EcChi1 and EcChi2, were identified by chitinolytic activity assay and LC-ESI-MS/MS. Their apparent molecular weights were 44 kDa and 65 kDa as determined by sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The specific activity of EcChi1 and EcChi2 was 1305.97 U·mg−1 and 28.69 U·mg−1. The optimal temperature and pH of EcChi1 were 37 °C and pH 4.0, respectively. Co2+, Fe3+, Zn2+, Cd2+, and Cu2+ had an obvious promoting effect upon chitinase activity of EcChi1. For colloidal chitin, the Km and Vmax values of EcChi1 were 2.09 mg·mL−1 and 31.15 U·mL−1·h−1. Full article

2014

Jump to: 2016, 2015, 2013, 2012

Open AccessArticle Profiling of Concanavalin A-Binding Glycoproteins in Human Hepatic Stellate Cells Activated with Transforming Growth Factor-β1
Molecules 2014, 19(12), 19845-19867; doi:10.3390/molecules191219845
Received: 27 September 2014 / Revised: 18 November 2014 / Accepted: 24 November 2014 / Published: 28 November 2014
Cited by 7 | PDF Full-text (4397 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Glycoproteins play important roles in maintaining normal cell functions depending on their glycosylations. Our previous study indicated that the abundance of glycoproteins recognized by concanavalin A (ConA) was increased in human hepatic stellate cells (HSCs) following activation by transforming growth factor-β1 (TGF-β1); however,
[...] Read more.
Glycoproteins play important roles in maintaining normal cell functions depending on their glycosylations. Our previous study indicated that the abundance of glycoproteins recognized by concanavalin A (ConA) was increased in human hepatic stellate cells (HSCs) following activation by transforming growth factor-β1 (TGF-β1); however, little is known about the ConA-binding glycoproteins (CBGs) of HSCs. In this study, we employed a targeted glycoproteomics approach using lectin-magnetic particle conjugate-based liquid chromatography-tandem mass spectrometry to compare CBG profiles between LX-2 HSCs with and without activation by TGF-β1, with the aim of discovering novel CBGs and determining their possible roles in activated HSCs. A total of 54 and 77 proteins were identified in the quiescent and activated LX-2 cells, respectively. Of the proteins identified, 14.3% were glycoproteins and 73.3% were novel potential glycoproteins. Molecules involved in protein processing in the endoplasmic reticulum (e.g., calreticulin) and calcium signaling (e.g., 1-phosphatidylinositol-4,5-bisphosphate phosphodiesterase β-2 [PLCB2]) were specifically identified in activated LX-2 cells. Additionally, PLCB2 expression was upregulated in the cytoplasm of the activated LX-2 cells, as well as in the hepatocytes and sinusoidal cells of liver cirrhosis tissues. In conclusion, the results of this study may aid future investigations to find new molecular mechanisms involved in HSC activation and antifibrotic therapeutic targets. Full article

2013

Jump to: 2016, 2015, 2014, 2012

Open AccessArticle Artificial and Natural Sialic Acid Precursors Influence the Angiogenic Capacity of Human Umbilical Vein Endothelial Cells
Molecules 2013, 18(3), 2571-2586; doi:10.3390/molecules18032571
Received: 9 October 2012 / Revised: 6 February 2013 / Accepted: 19 February 2013 / Published: 26 February 2013
Cited by 6 | PDF Full-text (545 KB) | HTML Full-text | XML Full-text
Abstract
N-acetylneuraminic acid (Neu5Ac) represents the most common terminal carbohydrate residue in many mammalian glycoconjugates and is directly involved in a number of different physiological as well as pathological cellular processes. Endogenous sialic acids derive from the biosynthetic precursor molecule N-acetyl-D-mannosamine (ManNAc).
[...] Read more.
N-acetylneuraminic acid (Neu5Ac) represents the most common terminal carbohydrate residue in many mammalian glycoconjugates and is directly involved in a number of different physiological as well as pathological cellular processes. Endogenous sialic acids derive from the biosynthetic precursor molecule N-acetyl-D-mannosamine (ManNAc). Interestingly, N-acyl-analogues of D-mannosamine (ManN) can also be incorporated and converted into corresponding artificial sialic acids by eukaryotic cells. Within this study, we optimized a protocol for the chemical synthesis of various peracetylated ManN derivatives resulting in yields of approximately 100%. Correct molecular structures of the obtained products ManNAc, N-propanoyl-ManN (ManNProp) and N-butyl-ManN (ManNBut) were verified by GC-, ESI-MS- and NMR-analyses. By applying these substances to human umbilical vein endothelial cells (HUVECs), we could show that each derivative was metabolized to the corresponding N-acylneuraminic acid variant and subsequently incorporated into nascent glycoproteins. To investigate whether natural and/or artificial sialic acid precursors are able to modulate the angiogenic capacity of HUVECs, a spheroid assay was performed. By this means, an increase in total capillary length has been observed when cells incorporated N-butylneuraminic acid (Neu5But) into their glycoconjugates. In contrast, the natural precursor ManNAc inhibited the growth of capillaries. Thus, sialic acid precursors may represent useful agents to modulate blood vessel formation. Full article
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Open AccessReview Chemistry and Applications of Polysaccharide Solutions in Strong Electrolytes/Dipolar Aprotic Solvents: An Overview
Molecules 2013, 18(1), 1270-1313; doi:10.3390/molecules18011270
Received: 26 October 2012 / Revised: 2 January 2013 / Accepted: 9 January 2013 / Published: 21 January 2013
Cited by 18 | PDF Full-text (989 KB)
Abstract
Biopolymers and their derivatives are being actively investigated as substitutes for petroleum-based polymers. This has generated an intense interest in investigating new solvents, in particular for cellulose, chitin/chitosan, and starch. This overview focuses on recent advances in the dissolution and derivatization of these
[...] Read more.
Biopolymers and their derivatives are being actively investigated as substitutes for petroleum-based polymers. This has generated an intense interest in investigating new solvents, in particular for cellulose, chitin/chitosan, and starch. This overview focuses on recent advances in the dissolution and derivatization of these polysaccharides in solutions of strong electrolytes in dipolar aprotic solvents. A brief description of the molecular structures of these biopolymers is given, with emphases on the properties that are relevant to derivatization, namely crystallinity and accessibility. The mechanism of cellulose dissolution is then discussed, followed by a description of the strategies employed for the synthesis of cellulose derivatives (carboxylic acid esters, and ethers) under homogeneous reaction conditions. The same sequence of presentation has been followed for chitin/chitosan and starch. Future perspectives for this subject are summarized, in particular with regard to compliance with the principles of green chemistry. Full article
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2012

Jump to: 2016, 2015, 2014, 2013

Open AccessArticle The Binding Affinity and Molecular Basis of the Structure-Binding Relationship between Urinary Tamm-Horsfall Glycoprotein and Tumor Necrosis Factor-α
Molecules 2012, 17(10), 11978-11989; doi:10.3390/molecules171011978
Received: 13 July 2012 / Revised: 26 September 2012 / Accepted: 8 October 2012 / Published: 11 October 2012
Cited by 5 | PDF Full-text (936 KB) | HTML Full-text | XML Full-text
Abstract
In a previous study we noted significant THP binding to TNF-α, but did not explore the molecular basis of the structure-binding relationship. In this study, we used lectin-binding ELISA to assess the carbohydrate compositions of THP, BSA, IgG, TNF-α, and IFN-g. We identified
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In a previous study we noted significant THP binding to TNF-α, but did not explore the molecular basis of the structure-binding relationship. In this study, we used lectin-binding ELISA to assess the carbohydrate compositions of THP, BSA, IgG, TNF-α, and IFN-g. We identified β(1,4)-N-acetylglucosamine oligomers (GlcNAc) and GlcNAc/branched mannose in BSA, IgG, TNF-α, and THP, but not in IFN-g. These carbohydrate moieties mediated binding with THP. Small amounts of Siaα(2,3)Gal/ GalNAc, Sia(2,6)Gal/GalNAc, and mannose residues were also present in THP and TNF-α. Binding affinity (Kd) between THP and TNF-α by Scatchard plot analysis was 1.4–1.7 × 10−6 M, lower than antigen-antibody or ligand-receptor binding affinities. To elucidate the structure-binding relationship of THP-TNF-α, THP was digested with neuraminidase, β-galactosidase, O-sialoglycoprotein endopeptidase, carboxypeptidase Y, or proteinase K. β-galactosidase increased binding capacity of THP for TNF-α. Monosaccharide inhibition suggested that α-methyl-D-mannoside, GlcNAc, and GalNAc, but not sialic acid, suppress THP-TNF-α binding as detected by ELISA. We conclude that sugar-lectin and sugar-protein interactions between cognate sites in THP and TNF-α mediate their binding. Full article
Open AccessArticle Syntheses of Sulfo-Glycodendrimers Using Click Chemistry and Their Biological Evaluation
Molecules 2012, 17(10), 11877-11896; doi:10.3390/molecules171011877
Received: 23 July 2012 / Revised: 5 September 2012 / Accepted: 18 September 2012 / Published: 9 October 2012
Cited by 7 | PDF Full-text (839 KB) | HTML Full-text | XML Full-text
Abstract
A series of novel glycol-clusters containing sulfonated N-acetyl-D-glucosamine (GlcNAc) have been synthesized using click chemistry. Three dendrimers with aromatic dendrons were synthesized using chlorination, azidation and click chemistries. The resulting dendrimers were modified with azide-terminated sulfonated GlcNAc using click chemistry. The sulfonated
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A series of novel glycol-clusters containing sulfonated N-acetyl-D-glucosamine (GlcNAc) have been synthesized using click chemistry. Three dendrimers with aromatic dendrons were synthesized using chlorination, azidation and click chemistries. The resulting dendrimers were modified with azide-terminated sulfonated GlcNAc using click chemistry. The sulfonated dendrimers showed affinity for proteins, including the lectin wheat germ agglutinin and amyloid beta peptide (1-42). The dendrimers of G1 and G2 in particular showed the largest affinity for the proteins. The addition of the sulfonated GlcNAc dendrimers of G1 and G2 exhibited an inhibition effect on the aggregation of the amyloid beta peptide, reduced the b-sheet conformation, and led to a reduction in the level of nanofiber formation. Full article
Open AccessArticle A Concise Synthesis of Glycolipids Based on Aspartic Acid Building Blocks
Molecules 2012, 17(10), 11346-11362; doi:10.3390/molecules171011346
Received: 31 July 2012 / Revised: 15 September 2012 / Accepted: 21 September 2012 / Published: 25 September 2012
Cited by 3 | PDF Full-text (288 KB) | HTML Full-text | XML Full-text
Abstract
L-Aspartic acid building blocks bearing galactosyl moieties were used to synthesise glycolipid mimetics of variable hydrocarbon chain length. The glycolipids were readily prepared through amide bond formation using the TBTU/HOBt coupling methodology. It was observed that, under these conditions, activation of the α-carboxylic
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L-Aspartic acid building blocks bearing galactosyl moieties were used to synthesise glycolipid mimetics of variable hydrocarbon chain length. The glycolipids were readily prepared through amide bond formation using the TBTU/HOBt coupling methodology. It was observed that, under these conditions, activation of the α-carboxylic acid of the intermediates led to near complete racemisation of the chiral centre if the reaction was carried out in the presence of a base such as triethylamine. The enantiomerically pure glycolipids were obtained after careful consideration of the synthetic sequence and by performing the coupling reactions in the absence of base. Full article
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Open AccessCommunication Inhibition of Burkholderia multivorans Adhesion to Lung Epithelial Cells by Bivalent Lactosides
Molecules 2012, 17(9), 10065-10071; doi:10.3390/molecules170910065
Received: 10 July 2012 / Revised: 2 August 2012 / Accepted: 6 August 2012 / Published: 24 August 2012
PDF Full-text (211 KB)
Abstract
Burkholderia cepacia complex (Bcc) is an opportunistic pathogen in cystic fibrosis patients which is inherently resistant to antimicrobial agents. The mechanisms of attachment and pathogenesis of Bcc, a group of 17 species, are poorly understood. The most commonly identified Bcc species in newly
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Burkholderia cepacia complex (Bcc) is an opportunistic pathogen in cystic fibrosis patients which is inherently resistant to antimicrobial agents. The mechanisms of attachment and pathogenesis of Bcc, a group of 17 species, are poorly understood. The most commonly identified Bcc species in newly colonised patients, Burkholderia multivorans, continues to be acquired from the environment. Development of therapies which can prevent or reduce the risk of colonization on exposure to Bcc in the environment would be a better alternative to antimicrobial agents. Previously, it has been shown that Bcc strains bound to many glycolipid receptors on lung epithelia. Using a real-time PCR method to quantify the levels of binding of B. multivorans to the lung epithelial cells, we have examined glycoconjugate derivatives for their potential to inhibit host cell attachment. Bivalent lactosides previously shown to inhibit galectin binding significantly reduced the attachment of B. multivorans to CF lung epithelial cells at micromolar concentrations. This was in contrast to monosaccharides and lactose, which were only effective in the millimolar range. Development of glycoconjugate therapies such as these, which inhibit attachment to lung epithelial cells, represent an alternative means of preventing infection with inherently antimicrobially resistant pathogens such as B. multivorans. Full article
Open AccessArticle Anti-metastatic Semi-synthetic Sulfated Maltotriose C-C Linked Dimers. Synthesis and Characterisation
Molecules 2012, 17(8), 9912-9930; doi:10.3390/molecules17089912
Received: 4 July 2012 / Revised: 8 August 2012 / Accepted: 9 August 2012 / Published: 17 August 2012
Cited by 6 | PDF Full-text (416 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
This manuscript describes the preparation and the spectroscopic characterisation of semi-synthetic sulfated maltotriose C-C linked dimers (SMTCs) where the natural C-O-C anomeric bond was substituted by one direct central C-C bond. This C-C bond induces conformation and flexibility changes with respect to the
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This manuscript describes the preparation and the spectroscopic characterisation of semi-synthetic sulfated maltotriose C-C linked dimers (SMTCs) where the natural C-O-C anomeric bond was substituted by one direct central C-C bond. This C-C bond induces conformation and flexibility changes with respect to the usual anomeric bond. SMTCs neutral precursors came from maltotriosyl bromide electroreduction through maltotriosyl radical intermediate dimerisation. The new C-C bond configuration, named for convenience a,a, a,b and b,b as the natural anomeric bond, dictated the statistic ratio formation of three diastereoisomers. They were separated by silica gel flash chromatography followed by semi preparative HPLC chromatography. Each diastereoisomer was exhaustively sulfated to afford the corresponding SMTCs. SMTCs were huge characterised by NMR spectroscopy which provided the sulfation degree, too. a,a and a,b were found quite homogeneous samples with a high degree of sulfation (85–95%). b,b appeared a non-homogeneous sample whose average sulfation degree was evaluated at around 78%. Mass spectroscopy experiments confirmed the sulfation degree range. Some considerations were proposed about SMTCs structure-biological properties. Full article
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Open AccessArticle Synthesis of Disaccharides Containing 6-Deoxy-a-L-talose as Potential Heparan Sulfate Mimetics
Molecules 2012, 17(8), 9790-9802; doi:10.3390/molecules17089790
Received: 28 June 2012 / Revised: 5 August 2012 / Accepted: 9 August 2012 / Published: 15 August 2012
Cited by 4 | PDF Full-text (297 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A 6-deoxy-a-L-talopyranoside acceptor was readily prepared from methyl a-L-rhamnopyranoside and glycosylated with thiogalactoside donors using NIS/TfOH as the promoter to give good yields of the desired a-linked disaccharide (69–90%). Glycosylation with a 2-azido-2-deoxy-D-glucosyl trichloroacetimidate donor was not completely stereoselective (a:b = 6:1), but
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A 6-deoxy-a-L-talopyranoside acceptor was readily prepared from methyl a-L-rhamnopyranoside and glycosylated with thiogalactoside donors using NIS/TfOH as the promoter to give good yields of the desired a-linked disaccharide (69–90%). Glycosylation with a 2-azido-2-deoxy-D-glucosyl trichloroacetimidate donor was not completely stereoselective (a:b = 6:1), but the desired a-linked disaccharide could be isolated in good overall yield (60%) following conversion into its corresponding tribenzoate derivative. The disaccharides were designed to mimic the heparan sulfate (HS) disaccharide GlcN(2S,6S)-IdoA(2S). However, the intermediates readily derived from these disaccharides were not stable to the sulfonation/deacylation conditions required for their conversion into the target HS mimetics. Full article
Open AccessArticle Design and Synthesis of a Novel Ganglioside Ligand for Influenza A Viruses
Molecules 2012, 17(8), 9590-9620; doi:10.3390/molecules17089590
Received: 9 July 2012 / Revised: 6 August 2012 / Accepted: 8 August 2012 / Published: 10 August 2012
Cited by 4 | PDF Full-text (444 KB) | HTML Full-text | XML Full-text
Abstract
A novel ganglioside bearing Neua2-3Gal and Neua2-6Gal structures as distal sequences was designed as a ligand for influenza A viruses. The efficient synthesis of the designed ganglioside was accomplished by employing the cassette coupling approach as a key reaction, which was executed between
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A novel ganglioside bearing Neua2-3Gal and Neua2-6Gal structures as distal sequences was designed as a ligand for influenza A viruses. The efficient synthesis of the designed ganglioside was accomplished by employing the cassette coupling approach as a key reaction, which was executed between the non-reducing end of the oligosaccharide and the cyclic glucosylceramide moiety. Examination of its binding activity to influenza A viruses revealed that the new ligand is recognized by Neua2-3 and 2-6 type viruses. Full article
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Open AccessArticle Accumulation of Unusual Gangliosides GQ3 and GP3 in Breast Cancer Cells Expressing the GD3 Synthase
Molecules 2012, 17(8), 9559-9572; doi:10.3390/molecules17089559
Received: 18 June 2012 / Revised: 20 July 2012 / Accepted: 6 August 2012 / Published: 10 August 2012
Cited by 13 | PDF Full-text (457 KB) | HTML Full-text | XML Full-text
Abstract
Glycosphingolipids from the ganglio-series are usually classified in four series according to the presence of 0 to 3 sialic acid residues linked to lactosylceramide. The transfer of sialic acid is catalyzed in the Golgi apparatus by specific sialyltransferases that show high specificity toward
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Glycosphingolipids from the ganglio-series are usually classified in four series according to the presence of 0 to 3 sialic acid residues linked to lactosylceramide. The transfer of sialic acid is catalyzed in the Golgi apparatus by specific sialyltransferases that show high specificity toward glycolipid substrates. ST8Sia I (EC 2.4.99.8, SAT-II, SIAT 8a) is the key enzyme controlling the biosynthesis of b- and c-series gangliosides. ST8Sia I is expressed at early developmental stages whereas in adult human tissues, ST8Sia I transcripts are essentially detected in brain. ST8Sia I together with b- and c-series gangliosides are also over-expressed in neuroectoderm-derived malignant tumors such as melanoma, glioblastoma, neuroblastoma and in estrogen receptor (ER) negative breast cancer, where they play a role in cell proliferation, migration, adhesion and angiogenesis. We have stably expressed ST8Sia I in MCF-7 breast cancer cells and analyzed the glycosphingolipid composition of wild type (WT) and GD3S+ clones. As shown by mass spectrometry, MCF-7 expressed a complex pattern of neutral and sialylated glycosphingolipids from globo- and ganglio-series. WT MCF-7 cells exhibited classical monosialylated gangliosides including GM3, GM2, and GM1a. In parallel, the expression of ST8Sia I in MCF-7 GD3S+ clones resulted in a dramatic change in ganglioside composition, with the expression of b- and c-series gangliosides as well as unusual tetra- and pentasialylated lactosylceramide derivatives GQ3 (II3Neu5Ac4-Gg2Cer) and GP3 (II3Neu5Ac5-Gg2Cer). This indicates that ST8Sia I is able to act as an oligosialyltransferase in a cellular context. Full article
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Open AccessArticle Synthesis, Antigenicity Against Human Sera and Structure-Activity Relationships of Carbohydrate Moieties from Toxocara larvae and Their Analogues
Molecules 2012, 17(8), 9023-9042; doi:10.3390/molecules17089023
Received: 21 June 2012 / Revised: 20 July 2012 / Accepted: 23 July 2012 / Published: 30 July 2012
Cited by 7 | PDF Full-text (560 KB) | HTML Full-text | XML Full-text
Abstract
Stereocontrolled syntheses of biotin-labeled oligosaccharide portions containing the Galβ1-3GalNAc core of the TES-glycoprotein antigen obtained from larvae of the parasite Toxocara and their analogues have been accomplished. Trisaccharides Fuc2Meα1-2Gal4Meβ1-3GalNAcα1-OR (A), Fucα1-2Gal4Meβ1-3GalNAcα1-OR (B), Fuc2Meα1-2Galβ1-3GalNAcα1-OR (C), Fucα1-2Galβ1-3GalNAcα1-OR (D
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Stereocontrolled syntheses of biotin-labeled oligosaccharide portions containing the Galβ1-3GalNAc core of the TES-glycoprotein antigen obtained from larvae of the parasite Toxocara and their analogues have been accomplished. Trisaccharides Fuc2Meα1-2Gal4Meβ1-3GalNAcα1-OR (A), Fucα1-2Gal4Meβ1-3GalNAcα1-OR (B), Fuc2Meα1-2Galβ1-3GalNAcα1-OR (C), Fucα1-2Galβ1-3GalNAcα1-OR (D) and a disaccharide Fuc2Meα1-2Gal4Meβ1-OR (E) (R = biotinylated probe) were synthesized by block synthesis using 5-(methoxycarbonyl)pentyl-2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyl-(1®3)-2-azide-4-O-benzyl-2-deoxy-α-D-galactopyranoside as a common glycosyl acceptor. We examined the antigenicity of these five oligosaccharides by enzyme linked immunosorbent assay (ELISA). Our results demonstrate that the O-methyl groups in these oligosaccharides are important for their antigenicity and the biotinylated oligosaccharides A, B, C and E have high serodiagnostic potential to detect infections caused by Toxocara larvae. Full article
Open AccessArticle Synthesis and Sensory Evaluation of ent-Kaurane Diterpene Glycosides
Molecules 2012, 17(8), 8908-8916; doi:10.3390/molecules17088908
Received: 29 June 2012 / Revised: 18 July 2012 / Accepted: 23 July 2012 / Published: 26 July 2012
Cited by 9 | PDF Full-text (230 KB) | HTML Full-text | XML Full-text
Abstract
Catalytic hydrogenation of the three ent-kaurane diterpene glycosides isolated from Stevia rebaudiana, namely rubusoside, stevioside, and rebaudioside-A has been carried out using Pd(OH)2 and their corresponding dihydro derivatives have been isolated as the products. Synthesis of reduced steviol glycosides was
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Catalytic hydrogenation of the three ent-kaurane diterpene glycosides isolated from Stevia rebaudiana, namely rubusoside, stevioside, and rebaudioside-A has been carried out using Pd(OH)2 and their corresponding dihydro derivatives have been isolated as the products. Synthesis of reduced steviol glycosides was performed using straightforward chemistry and their structures were characterized on the basis of 1D and 2D NMR spectral data and chemical studies. Also, we report herewith the sensory evaluation of all the reduced compounds against their corresponding original steviol glycosides and sucrose for the sweetness property of these molecules. Full article
Open AccessArticle Application of Paramagnetic NMR-Validated Molecular Dynamics Simulation to the Analysis of a Conformational Ensemble of a Branched Oligosaccharide
Molecules 2012, 17(6), 6658-6671; doi:10.3390/molecules17066658
Received: 11 April 2012 / Revised: 29 May 2012 / Accepted: 29 May 2012 / Published: 31 May 2012
Cited by 16 | PDF Full-text (696 KB)
Abstract
Oligosaccharides of biological importance often exhibit branched covalent structures and dynamic conformational multiplicities. Here we report the application of a method that we developed, which combined molecular dynamics (MD) simulations and lanthanide-assisted paramagnetic NMR spectroscopy, to evaluate the dynamic conformational ensemble of a
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Oligosaccharides of biological importance often exhibit branched covalent structures and dynamic conformational multiplicities. Here we report the application of a method that we developed, which combined molecular dynamics (MD) simulations and lanthanide-assisted paramagnetic NMR spectroscopy, to evaluate the dynamic conformational ensemble of a branched oligosaccharide. A lanthanide-chelating tag was attached to the reducing end of the branched tetrasaccharide of GM2 ganglioside to observe pseudocontact shifts as the source of long distance information for validating the conformational ensemble derived from MD simulations. By inspecting the results, the conformational space of the GM2 tetrasaccharide was compared with that of its nonbranched derivative, the GM3 trisaccharide. Full article
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Open AccessArticle Glycosylation of Vanillin and 8-Nordihydrocapsaicin by Cultured Eucalyptus perriniana Cells
Molecules 2012, 17(5), 5013-5020; doi:10.3390/molecules17055013
Received: 29 March 2012 / Revised: 17 April 2012 / Accepted: 23 April 2012 / Published: 2 May 2012
Cited by 4 | PDF Full-text (219 KB) | Supplementary Files
Abstract
Glycosylation of vanilloids such as vanillin and 8-nordihydrocapsaicin by cultured plant cells of Eucalyptus perriniana was studied. Vanillin was converted into vanillin 4-O-b-D-glucopyranoside, vanillyl alcohol, and 4-O-b-D-glucopyranosylvanillyl alcohol by E. perriniana cells. Incubation of cultured E. perriniana cells with
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Glycosylation of vanilloids such as vanillin and 8-nordihydrocapsaicin by cultured plant cells of Eucalyptus perriniana was studied. Vanillin was converted into vanillin 4-O-b-D-glucopyranoside, vanillyl alcohol, and 4-O-b-D-glucopyranosylvanillyl alcohol by E. perriniana cells. Incubation of cultured E. perriniana cells with 8-nor- dihydrocapsaicin gave 8-nordihydrocapsaicin 4-O-b-D-glucopyranoside and 8-nordihydro- capsaicin 4-O-b-D-gentiobioside. Full article
Open AccessArticle 1D 13C-NMR Data as Molecular Descriptors in Spectra — Structure Relationship Analysis of Oligosaccharides
Molecules 2012, 17(4), 3818-3833; doi:10.3390/molecules17043818
Received: 9 February 2012 / Revised: 19 March 2012 / Accepted: 23 March 2012 / Published: 28 March 2012
Cited by 2 | PDF Full-text (310 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Spectra-structure relationships were investigated for estimating the anomeric configuration, residues and type of linkages of linear and branched trisaccharides using 13C-NMR chemical shifts. For this study, 119 pyranosyl trisaccharides were used that are trimers of the α or β anomers of D-glucose,
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Spectra-structure relationships were investigated for estimating the anomeric configuration, residues and type of linkages of linear and branched trisaccharides using 13C-NMR chemical shifts. For this study, 119 pyranosyl trisaccharides were used that are trimers of the α or β anomers of D-glucose, D-galactose, D-mannose, L-fucose or L-rhamnose residues bonded through a or b glycosidic linkages of types 1→2, 1→3, 1→4, or 1→6, as well as methoxylated and/or N-acetylated amino trisaccharides. Machine learning experiments were performed for: (1) classification of the anomeric configuration of the first unit, second unit and reducing end; (2) classification of the type of first and second linkages; (3) classification of the three residues: reducing end, middle and first residue; and (4) classification of the chain type. Our previously model for predicting the structure of disaccharides was incorporated in this new model with an improvement of the predictive power. The best results were achieved using Random Forests with 204 di- and trisaccharides for the training set—it could correctly classify 83%, 90%, 88%, 85%, 85%, 75%, 79%, 68% and 94% of the test set (69 compounds) for the nine tasks, respectively, on the basis of unassigned chemical shifts. Full article
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