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Carbohydrate Research

Alexander A Karelin, Nadezhda E Ustyuzhanina, Yury E Tsvetkov, Nikolay E Nifantiev
The disaccharide β-d-mannopyranosyl-(1 → 2)-d-mannopyranose obtained by chemical cleavage and enzymatic dephosphorylation of biotechnologically available phosphomannan was transformed over six steps into a biotinylated probe suitable for assessment of carbohydrate specificity of antibodies induced by yeast cell wall preparations.
November 1, 2018: Carbohydrate Research
Anne Berit C Samuelsen, Frode Rise, Alistair L Wilkins, Lioubov Teveleva, Anna Armika Tussilago Nyman, Finn L Aachmann
Albatrellus ovinus, the sheep polypore, is a large, dense mushroom being rich in cell wall material. Polysaccharides were isolated by sequential extraction, enzymatic treatment and analyzed with respect to monosaccharide composition, glycosidic linkages by methylation and GC-MS as well as NMR spectroscopy. A fucogalactan composed of an (1 → 6)-α-d-galactan backbone with single α-l-Fucp residues attached at O-2 was identified in the hot water extract obtained after treatment with a protease and size exclusion chromatography...
November 1, 2018: Carbohydrate Research
Joachim Thiem, Henry Sajus
By sequential synthesis the four 2,6-dideoxy saccharide moieties of the kijanimicin tetrasaccharide could be stereoselectively assembled. For formation of all required 2-deoxy α-glycoside linkages various S-(hexopyranosyl)-phosphorodithioates as donor structures could be convincingly employed. The terminal 2-deoxy β-glycoside linkage was stereoselectively formed following the dibromomethyl methyl ether approach. The target octadeoxy-tetrasaccha-ride could be obtained via nine subsequent steps in 5% overall yield...
November 1, 2018: Carbohydrate Research
Charles Gauthier, Serge Lavoie, Marianne Piochon, Sarah Martinez, Sylvain Milot, Eric Déziel
The bacterium Pantoea ananatis was reported to produce glycolipid biosurfactants of unknown structures. Herein, we present the isolation and structural determination of ananatoside A, the main congener of a new family of 15-membered macrodilactone-containing glucolipids. The structure of ananatoside A was elucidated via chemical degradation and spectroscopic methods including 1D/2D NMR analysis, tandem MS/MS, GC-MS, HR-ESI-TOF-MS, MALDI-TOF-MS, and polarimetry. Computational methods were used to predict the most abundant conformers of ananatoside A...
October 28, 2018: Carbohydrate Research
Michelle O Igual, Paulo S G Nunes, Rafael M da Costa, Susimaire P Mantoani, Rita C Tostes, Ivone Carvalho
O-GlcNAcylation or O-GlcNAc modification is a post-translational modification of several proteins responsible for fundamental cellular processes. Dysregulation of the O-GlcNAc pathway has been linked to the etiology of several diseases such as neurodegenerative and cardiovascular diseases, type 2 diabetes and cancer. O-GlcNAcase (OGA) catalyzes the removal of O-GlcNAc from the modified proteins and several carbohydrate-based OGA inhibitors have been synthesized to understand the role of O-GlcNAc-modified proteins in physiological and pathological conditions...
October 26, 2018: Carbohydrate Research
Marcelo R Necol, M Soledad Vela Gurovic, Soledad Ruiz Díaz, Gustavo F Silbestri
No abstract text is available yet for this article.
October 26, 2018: Carbohydrate Research
Chunlai Feng, Jin Wang, Qiujie Tang, Zijian Zhong, Shusen Qiao, Xingyu Liu, Can Chen, Aihua Zhou
Glycosyl phenylthiosulfonates are reagents which are valuable for the S-glycosylation decoration of organic compounds and proteins. Here, one-pot multiple-component synthesis of glycosyl phenylthiosulfonates from sulfinate, sulfur powder and glycosyl bromides is reported. The reactions afford glycosyl phenylthiosulfonates in good yields under mild conditions. Further application and exploration of glycosyl phenylthiosulfonates are still on underway in our group.
October 19, 2018: Carbohydrate Research
Sanaz Ahmadipour, Laura Beswick, Gavin J Miller
No abstract text is available yet for this article.
September 14, 2018: Carbohydrate Research
Qaojuan Yan, Hongye Yang, Zhengqiang Jiang, Erwei Liu, Shaoqing Yang
Fermentation conditions for β-1,3-1,4-glucanase (TaGlu34) production in submerged culture by a thermophilic fungus, Thermoascus aurantiacus CAU830 were optimized. The highest enzyme activity of 3741 U/mL was obtained, and the crude enzyme was purified to homogeneity with a purification fold of 7.3 and a recovery yield of 11.6%. The molecular mass of the purified enzyme was estimated to be approximately 34 kDa on SDS-PAGE. TaGlu34 was most active at pH 6.0 and 75 °C, respectively. It showed excellent thermostability with thermal denaturing half-lives of 209, 130 and 69 min at 50, 60 and 70 °C, respectively...
September 5, 2018: Carbohydrate Research
Laxminarayan Sahoo, Soumya Kundu, Anadi Singhamahapatra, Naresh K Jena, Ganesh C Nayak, Satyanarayan Sahoo
In recent years, 1,4-triazole rings are being widely used for the synthesis of carbohydrate derived biomimetics, due to their easy synthesis and wide range of functional group compatibility. These triazole rings lead to synthetic molecules with improved enzymatic stability, bioavailability, and structural diversity. In this present work, a benzoyl group has been introduced at the C-5 position of the triazole ring present in the synthetic glycoconjugates providing further structural diversity to the molecule...
August 31, 2018: Carbohydrate Research
Mojtaba Tabandeh, Ean Wai Goh, Abbas Abdulameer Salman, Thorsten Heidelberg, Rusnah Syahila Duali Hussen
Two azide-terminated oligoethylene oxide spacered glycolipids have been synthesized, and their assembly behavior has been studied in comparison to the corresponding base surfactants. The results suggest potential of the Guerbet lactoside-based compound for targeted drug delivery, while a coiling of the ethylene oxide linker disfavors the application of the glucoside.
August 30, 2018: Carbohydrate Research
Ying Xiao, Zimin Lu, Xiang Zhao, Pinru Wu, Wei Chen, Ruobin Wang, Jing Zeng, Qian Wan
A catalytic and metal free sulfoxidation of O-2-(2-propylthiol)benzyl (OPTB) glycosides to O-2-(2-propylsulfinyl)benzyl (OPSB) glycosides has been developed by introducing NOBF4 as catalyst, oxygen as terminal oxidant and TBAB as additive. Wide variety of OPTB glycosides were efficiently oxidized without observation of over oxidation. The allowance of large scale synthesis, easy operation and purification highlighted its practical application in construction of complex oligosaccharides and glycoconjugates employing interrupted Pummerer reaction mediated glycosylation strategy...
August 24, 2018: Carbohydrate Research
Hye-Bin Kim, Kyung-Tai Lee, Min-Ju Kim, Jin-Sung Lee, Keun-Sung Kim
This study was conducted to isolate and functionally characterize a novel xylan-degrading enzyme from the microbial metagenomes of black goat rumens. A novel gene, KG42, was isolated from one of the 17 xylan-degrading metagenomic fosmid clones obtained from black goat rumens. The KG42 gene, comprising a 1107 bp open reading frame, encodes a protein composed of 368 amino acids (41 kDa) with a glycosyl hydrolase family 10 (GH10) domain, consisting of a "salad-bowl" shaped tertiary structure (a typical 8-fold α/β barrel (α/β)8) and two catalytic residues...
August 22, 2018: Carbohydrate Research
Martina Kašáková, Lenka Malinovská, Tomáš Klejch, Martina Hlaváčková, Hana Dvořáková, Eva Fujdiarová, Zdeňka Rottnerová, Olga Maťátková, Pavel Lhoták, Michaela Wimmerová, Jitka Moravcová
As a part of ongoing activities towards the design of ligands against pathogenic lectins, a synthesis of original α-C-galacto/α-C-manno/α-C-fucopyranosyl glycomimetics based on a calix[4]arene scaffold and their binding evaluation is described. The interactions of the glycomimetics with seven lectins of various origins were carried out using agglutination inhibition assays. The 1,3-alternate tetra-C-fucosylated ligand and its derivative having a tertBu group at the upper rim of the calix[4]arene scaffold were the most potent towards the AAL lectin family (RSL, AFL, AAL, AOL) and BC2L-C...
August 21, 2018: Carbohydrate Research
HienT T Pham, Lubbert Dijkhuizen, Sander S van Leeuwen
β-Galacto-oligosaccharides (GOS) are used commercially in infant nutrition, aiming to functionally replace human milk oligosaccharides (hMOS). Glucansucrases Gtf180-ΔN and GtfA-ΔN of Lactobacillus reuteri strains convert sucrose into α-glucans with (α1→6)/(α1→3) and (α1→4)/(α1→6) glucosidic linkages, respectively. Previously we reported that both glucansucrases glucosylate lactose, producing a minimum of 5 compounds (degree of polymerization 3-4) (GL34 mixture) with (α1→2/3/4) linkages. This GL34 mixture exhibited growth stimulatory effects on various probiotic bacteria...
December 2018: Carbohydrate Research
Inka Brockhausen, Elena Elimova, Ashley M Woodward, Pablo Argüeso
Mucin glycoproteins on the ocular surface are rich in O-glycans and have important roles in the protection from physical, chemical and microbial impact. In this work, we have cultured human corneal and conjunctival epithelial cells to examine the glycosyltransferase activities that synthesize the O-glycans of mucins. The results indicate that ocular surface epithelial cells have active enzymes that synthesize O-glycans with sialylated core 1, Galβ1-3GalNAcα, and core 2, GlcNAcβ1-6(Galβ1-3)GalNAcα structures which corresponds to previous structural studies...
December 2018: Carbohydrate Research
Sanjay Manhas, Mark S Taylor
An N-methylpyridinium-4-boronic ester acts as a catalyst for dehydrative glycosidations of 2-deoxy sugar-derived hemiacetals. The catalytic protocol is tolerant of functionalized acceptors, including alcohols bearing isopropylidene ketal, tert-butyl carbamate or benzyl carbamate groups. The results demonstrate that organoboron-catalyzed substitution reactions of alcohols, which have previously been conducted on π-activated (benzylic, allylic or propargylic) substrates, can also be used to achieve C-O bond formation from carbohydrate-derived hemiacetals...
December 2018: Carbohydrate Research
Yanjun Chen, Wenfang Dou, Heng Li, Jinsong Shi, Zhenghong Xu
Alginate oligosaccharides are depolymerization products of alginate by enzymatic degradation or physicochemical treatments. Alginate lyase has received great interests due to its use in oligosaccharide preparation. The substrate specificity of alginate lyase directly determines the type and degree of polymerization of alginate oligosaccharides. In this paper, the degradation products of Alginate lyase from Isoptericola halotolerans CGMCC 5336 were size-fractionated by gel filtration chromatography and the fractions were characterized by TLC, HPLC, MS and 1 H NMR spectroscopy...
December 2018: Carbohydrate Research
Marina O Nagornaya, Anna V Orlova, Elena V Stepanova, Alexander I Zinin, Tatiana V Laptinskaya, Leonid O Kononov
A new glycosyl acceptor to be used in sialylation was designed as a 3-hydroxy derivative of 4-methoxyphenyl β-d-galactopyranoside with 2-O-acetyl group and O-4 and O-6 protected as benzylidene acetal. Two alternative syntheses of this compound were compared. Sialylation of 3-OH group of the glycosyl acceptor with O-chloroacetylated N-trifluoroacetylneuraminic acid phenyl thioglycoside (NIS, TfOH, MeCN, MS 3 Å, -40 °C) was studied in a wide concentration range (5-150 mmol L-1 ). The outcome of sialylation generally followed the predictions of supramer analysis of solutions of sialyl donor in MeCN, which was performed by polarimetry and static light scattering and revealed two concentration ranges differing in solution structure and the structures of supramers of glycosyl donor...
December 2018: Carbohydrate Research
Edward S Hems, Sergey A Nepogodiev, Martin Rejzek, Robert A Field
No abstract text is available yet for this article.
December 2018: Carbohydrate Research
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