Read by QxMD icon Read

Carbohydrate Research

Nicolas Lenfant, Matthieu Hainaut, Nicolas Terrapon, Elodie Drula, Vincent Lombard, Bernard Henrissat
Lytic polysaccharide monooxygenases of family AA9 catalyze the oxidative cleavage of glycosidic bonds in cellulose and related polysaccharides. The N-terminal half of AA9 LPMOs displays a huge sequence variability that is in contradiction with the substrate simplicity so far observed for these enzymes. To understand the cause of the high multigenicity that prevails in the family, we have performed a clustering analysis of the N-terminal region of 3400 sequences of family AA9 LPMOs, and have evaluated the coincidence of the clusters with distal visible features that may accompany functional differences...
April 13, 2017: Carbohydrate Research
Nicolas Petry, Timothé Vucko, Charlotte Collet, Sandrine Lamandé-Langle, Nadia Pellegrini-Moïse, Françoise Chrétien
α- and β-C-allylglucopyranosides and hydroxy-, bromo- and azido-derivatives were prepared through allylation at C-1 of methyl 2,3,4,6-tetra-O-benzyl-D-glucopyranoside or 1-O-acetyl-2,3,4,6-tetra-O-benzyl-D-glucopyranose and subsequent chemical modifications of the alkene on the anomeric arm. However, we picked out some discordance between some recent published studies and our results. After a thorough work of characterization and NMR analysis, we unambiguously confirmed α and β stereochemistry of the two series of compounds and fully described for the first time β-C-propyl alcohol, bromide and azide of 2,3,4,6-tetra-O-benzyl-D-glucopyranose...
April 12, 2017: Carbohydrate Research
Kelly B Rodrigues, Jéssica K A Macêdo, Tallyta Teixeira, Jéssica S Barros, Ana C B Araújo, Fernanda P Santos, Betânia F Quirino, Bruno S A F Brasil, Thaís F C Salum, Patrícia V Abdelnur, Léia C L Fávaro
The discovery of lytic polysaccharides monooxygenases copper dependent (LPMOs) revolutionized the classical concept that the cleavage of cellulose is a hydrolytic process in recent years. These enzymes carry out oxidative cleavage of cellulose (and other polysaccharides), acting synergistically with cellulases and other hydrolases. In fact, LPMOs have the potential for increasing the efficiency of the lignocellulosic biomass conversion in biofuels and high value chemicals. Among a small number of microbial LPMOs that have been characterized, some LPMOs were expressed and characterized biochemically from the bacteria Thermobifida fusca, using the host Escherichia coli...
April 9, 2017: Carbohydrate Research
Rachel Hevey, Chang-Chun Ling
β-D-Idopyranosides are interesting sugars because of their unusual conformational flexibility in the pyranosyl ring, and also their β-1,2-cis-anomeric configuration. Here we report our studies of the regioselective opening of 4,6-O-benzylidene-protected β-D-idopyranosides under reducing conditions, and the subsequent 6-homologation via Swern oxidation and Wittig olefination to afford a 6,7-dideoxy-β-D-ido-hept-6-enopyranoside. This olefination product was found to adopt predominantly (1)C4 conformation in solution by NMR experiments, which places the vinyl group at a more sterically hindered axial position and creates difficulty in subsequent hydroborations...
April 8, 2017: Carbohydrate Research
Hiroyuki Kono
Three samples of ethyl cellulose (EC) with different degrees of substitution (DS)-0.51, 1.41, and 2.28-were prepared by a slurry method using ethyl bromide as the etherification reagent. (1)H-(13)C HSQC and HSQC-TOCSY NMR spectral analysis allowed for complete assignment of the (1)H and (13)C chemical shifts, respectively, of eight anhydroglucose units (AGUs) comprising EC chains-un-, 2-mono-, 3-mono-, 6-mono-, 2,3-di-, 2,6-di-, 3,6-di-, and 2,3,6-tri-substituted AGUs. In addition, the lineshape of the quantitative (13)C NMR spectra of the three EC samples provided change in the mole fractions of these AGUs against DS, making it possible to estimate the reaction mechanism for the production of EC, elucidating reactivities of the hydroxyl groups at the 2, 3, and 6 positions of cellulose and interactions between the substituent groups within the same AGU and vicinal AGUs...
April 6, 2017: Carbohydrate Research
Chao Chen, Xi Hou, Natalia Utkina, Leonid Danilov, Dawei Zhou, Vladimir Torgov, Vladimir Veselovsky, Bin Liu, Lu Feng
Glycosyltransferases (GTs) catalyze the formation of regio- and stereospecific glycosidic linkages between specific sugar donors and recipients. In this study, the function of the wfcD gene from the Escherichia coli O141 O-antigen gene cluster encoding an α-1,3-mannosyltransferase that catalyzed the formation of the linkage Man(α1-3)-GlcNAc was biochemically characterized. WfcD was expressed in E. coli BL21 (DE3), and the enzymatic product was identified by liquid chromatography-mass spectrometry (LC-MS), collision-induced dissociation electrospray ionization ion trap multiple tandem MS (CID-ESI-IT-MS(n)) and glycosidase digestion using the donor substrate GDP-Man and the synthetic acceptor substrate decyl diphosphate 2-acetamido-2-deoxy-α-D-glucopyranose (GlcNAc-PP-De)...
April 6, 2017: Carbohydrate Research
Baoqi Cai, Yanping Luo, Qianqian Guo, Xinge Zhang, Zhongming Wu
Hydrogels are good candidates to satisfy many needs for functional and tunable biomaterials. How to precisely control the gel structure and functions is crucial for the construction of sophisticated soft biomaterials comprising the hydrogels, which facilitates the impact of the surrounding environment on a unique biological function occurring. Here, glucose-responsive hydrogels comprised of 3-acrylamidophenyl boronic acid copolymerized with 2-lactobionamidoethyl methacrylate (p(APBA-b-LAMA)) were synthesized, and further evaluated as carriers for insulin delivery...
April 6, 2017: Carbohydrate Research
Masahito Hashimoto, Masato Mizukami, Ken-Ichi Osuki, Nagatoshi Fujiwara, Yasuo Suda, Toshiki Uchiumi
Mesorhizobium loti is a member of rhizobia and establishes nitrogen-fixing symbioses with several Lotus species. Recently, we reported that M. loti MAFF 303099 bacterial cells and their lipopolysaccharide (LPS) preparations are involved in the beginning of the symbiotic process by inducing transient nitric oxide (NO) production in the roots of L. japonicus. We subsequently found that both the polysaccharide (PS) part and the lipid A moiety in LPS are responsible for the NO induction. In this study, we elucidated the chemical structure of M...
April 4, 2017: Carbohydrate Research
Karolina Ossowska, Małgorzata Czerwicka, Wojciech Sledz, Sabina Zoledowska, Agata Motyka, Małgorzata Golanowska, Guy Condemine, Ewa Lojkowska, Zbigniew Kaczyński
O-polysaccharides were isolated from lipopolysaccharides obtained from four different strains of plant pathogenic bacteria belonging to the species Dickeya solani: two of them were isolated in Poland (IFB0099 and IFB0158), the third in Germany (IFB0223) and the last one, D. solani Type Strain IPO2222, originated from the Netherlands. In addition, the O-polysaccharide of a closely related species D. dadantii strain 3937 was isolated. The purified polysaccharides of the five strains were analyzed using NMR spectroscopy and chemical methods...
April 1, 2017: Carbohydrate Research
Pengfei Zhang, Chang-Chun Ling
A mild acetolysis method for the regioselective removal of isopropylidene group from di-O-isopropylidene-protected hexopyranosides is reported. O-Isopropylidene-protected intermediates play an important role in carbohydrate chemistry, as they are often found in commercially available furanosyl and pyranosyl materials, and some of them contain more than one O-isopropylidene groups. Methods that permit regioselective removal of O-isopropylidene groups are extremely valuable, as the number of steps in the total synthesis of complex oligosaccharides could be significantly decreased...
March 30, 2017: Carbohydrate Research
Si-Qi Jiang, Yu-Bo Zhang, Min Xiao, Lin Jiang, Ding Luo, Qian-Wen Niu, Yao-Lan Li, Xian-Tao Zhang, Guo-Cai Wang
Six new cycloartane triterpenoid saponins, thalisides A-F (1-6), along with four known ones (7-10), were isolated from Thalictrum fortunei. The new structures were elucidated by using spectroscopic data (NMR, IR, UV, and MS). Compounds 1-10 were examined for their in vitro cytotoxicity against two human cancer cell lines (HepG2, A549) and antiviral activity against influenza A virus (H1N1) and found to be inactive.
March 30, 2017: Carbohydrate Research
Kristian E H Frandsen, Jens-Christian N Poulsen, Tobias Tandrup, Leila Lo Leggio
Lytic polysaccharide monooxygenases (LPMOs) have been found to be key components in microbial (bacterial and fungal) degradation of biomass. They are copper metalloenzymes that degrade polysaccharides oxidatively and act in synergy with glycoside hydrolases. Recently crystallographic studies carried out at pH 5.5 of the LPMO from Lentinus similis belonging to the fungal LPMO family AA9 have provided the first atomic resolution view of substrate-LPMO interactions. The LsAA9A structure presented here determined at pH 3...
March 24, 2017: Carbohydrate Research
María Emilia Cano, Oscar Varela, María Isabel García-Moreno, José Manuel García Fernández, José Kovensky, María Laura Uhrig
The synthesis of mono and divalent β-galactosylamides linked to a hydroxylated chain having a C2 symmetry axis derived from l-tartaric anhydride is reported. Reference compounds devoid of hydroxyl groups in the linker were also prepared from β-galactosylamine and succinic anhydride. After functionalization with an alkynyl residue, the resulting building blocks were grafted onto different azide-equipped scaffolds through the copper catalyzed azide-alkyne cycloaddition. Thus, a family of structurally related mono and divalent β-N-galactopyranosylamides was obtained and fully characterized...
March 23, 2017: Carbohydrate Research
Galina Pazynina, Marina Sablina, Tatiana Ovchinnikova, Tatiana Tyrtysh, Svetlana Tsygankova, Alexander Tuzikov, Kira Dobrochaeva, Nadezhda Shilova, Nailia Khasbiullina, Nicolai Bovin
Our understanding of biological role of glycans O-sulfation remains at the level of beginners due to microheterogeneity, lability and other difficulties of exact structural assignment. Partially, problem of functional investigations, especially determination of glycoepitope specificity of carbohydrate-binding proteins could be solved with the help of synthetic glycans of certain structure. Here we summing up our synthetic efforts in creation of synthetic O-sulfatome, and bring together all the synthesized in our group sulfated glycans, both existing in nature, yet undiscovered but biochemically licit, and completely unnatural...
March 22, 2017: Carbohydrate Research
Svetlana V Tomshich, Maxim S Kokoulin, Anatoliy I Kalinovsky, Ol'ga I Nedashkovskaya, Nadezhda A Komandrova
The O-polysaccharide was isolated from the lipopolysaccharide of Cellulophaga algicola and studied by chemical analyses along with (1)H and (13)C NMR spectroscopy, including 2D (1)H, (1)H COSY, TOCSY, ROESY, (1)Н, (13)С HSQC, HMBC experiments. It was found that the polysaccharide is built up of branched pentasaccharide repeating units, containing D-mannose (Man), D-glucuronic acid (GlcA), N-acetyl-D-glucosamine (GlcNAc), two L-rhamnose (Rha) residues and O-acetyl groups in a non-stoichiometric amount and has the following structure...
March 22, 2017: Carbohydrate Research
Beatrice Bonora, Irene Boos, Mads H Clausen
Arabinoxylans (AX) are a major class of hemicellulose and an important polysaccharide component of lignocellulosic biomass. To utilize the glycan polymer effectively, it is desirable to learn more about the enzymatic hydrolysis of AXs. Well-defined glycans can help to elucidate these processes. Here, we report the efficient synthesis of a mixed O- and S-linked tetraxylan. This thio-oligosaccharide has been developed as a putative inhibitor of arabinoxylan degrading enzymes used for the saccharification of biomass...
March 21, 2017: Carbohydrate Research
Michael Santiago Cintrón, Glenn P Johnson, Alfred D French
The interaction of two methanol molecules, simplified models of carbohydrates and cellulose, was examined using a variety of quantum mechanics (QM) levels of theory. Energy plots for hydrogen bonding distance (H⋯O) and angle (OH⋯O) were constructed. All but two experimental structures were located in stabilized areas on the vacuum phase energy plots. Each of the 399 models was analyzed with Bader's atoms-in-molecules (AIM) theory, which showed a widespread ability by the dimer models to form OH⋯O hydrogen bonds that have bond paths and Bond Critical Points...
March 19, 2017: Carbohydrate Research
Gabriela Oleas, Eduardo Callegari, Romina Sepúlveda, Jaime Eyzaguirre
The lignocellulolytic fungus, Penicillium purpurogenum, grows on a variety of natural carbon sources, among them sugar beet pulp. Culture supernatants of P. purpurogenum grown on sugar beet pulp were partially purified and the fractions obtained analyzed for esterase activity by zymograms. The bands with activity on methyl umbelliferyl acetate were subjected to mass spectrometry to identify peptides. The peptides obtained were probed against the proteins deduced from the genome sequence of P. purpurogenum...
March 18, 2017: Carbohydrate Research
K B Möllers, H Mikkelsen, T I Simonsen, D Cannella, K S Johansen, M J Bjerrum, C Felby
Light-driven activation of lytic polysaccharide monooxygenases (LPMOs) has been attributed to the transfer of high redox potential electrons from excited photopigments to the enzyme. However, due to the formation of reactive oxygen species (ROS) in such a system, not only electrons from the pigments but also ROS could be part of the enzyme mechanism. This work investigates the role of ROS in the oxidation of phosphoric acid swollen cellulose (PASC) by a light-driven LPMO system. Our results clearly show that the addition of superoxide dismutase or catalase to remove ROS did not attenuate the capacity of the light-driven LPMO system to oxidize PASC, as measured by formation of oxidized oligosaccharides...
March 18, 2017: Carbohydrate Research
Chisa Aoki, Yoshihiro Takeuchi, Kenjirou Higashi, Yuta Okamoto, Akihito Nakanishi, Mahamadou Tandia, Jun Uzawa, Keisuke Ueda, Kunikazu Moribe
We report the full assignment of (1)H and (13)C NMR signals belonging to α-glucosyl rhoifolin (Rhf-G), a novel transglycosylated compound synthesized from a flavone glycoside, rhoifolin, as well as its chemical structure. Furthermore, we report the complete NMR signal assignment for another transglycosylated compound, α-glucosyl rutin (Rutin-G), as the signals corresponding to its sugar moieties had not been identified. Electrospray ionization-mass spectrometry along with multiple NMR methods revealed that Rhf-G possesses three sugar moieties in its chemical structure...
March 16, 2017: Carbohydrate Research
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"