for Journals by Title or ISSN
for Articles by Keywords
help
  Subjects -> CHEMISTRY (Total: 831 journals)
    - ANALYTICAL CHEMISTRY (47 journals)
    - CHEMISTRY (584 journals)
    - CRYSTALLOGRAPHY (22 journals)
    - ELECTROCHEMISTRY (26 journals)
    - INORGANIC CHEMISTRY (41 journals)
    - ORGANIC CHEMISTRY (45 journals)
    - PHYSICAL CHEMISTRY (66 journals)

CHEMISTRY (584 journals)                  1 2 3 4 5 6 | Last

2D Materials     Hybrid Journal   (Followers: 5)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 31)
ACS Catalysis     Full-text available via subscription   (Followers: 27)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 16)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 17)
ACS Macro Letters     Full-text available via subscription   (Followers: 20)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 24)
ACS Nano     Full-text available via subscription   (Followers: 196)
ACS Photonics     Full-text available via subscription   (Followers: 5)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 12)
Acta Chemica Iasi     Open Access  
Acta Chimica Sinica     Full-text available via subscription  
Acta Chimica Slovaca     Open Access   (Followers: 5)
Acta Chromatographica     Full-text available via subscription   (Followers: 9)
Acta Facultatis Medicae Naissensis     Open Access   (Followers: 1)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 6)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 5)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 11)
Advanced Functional Materials     Hybrid Journal   (Followers: 41)
Advanced Science Focus     Free   (Followers: 1)
Advances in Chemical Engineering and Science     Open Access   (Followers: 24)
Advances in Chemical Science     Open Access   (Followers: 9)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 14)
Advances in Drug Research     Full-text available via subscription   (Followers: 17)
Advances in Enzyme Research     Open Access  
Advances in Fluorine Science     Full-text available via subscription   (Followers: 7)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 13)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 14)
Advances in Nanoparticles     Open Access   (Followers: 11)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 9)
Advances in Polymer Science     Hybrid Journal   (Followers: 37)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 10)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6)
African Journal of Chemical Education     Open Access   (Followers: 1)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 5)
Afrique Science : Revue Internationale des Sciences et Technologie     Open Access   (Followers: 1)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 1)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 4)
AMB Express     Open Access  
Ambix     Hybrid Journal   (Followers: 2)
American Journal of Applied Sciences     Open Access   (Followers: 30)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 85)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 11)
American Journal of Chemistry     Open Access   (Followers: 20)
American Journal of Plant Physiology     Open Access   (Followers: 10)
American Mineralogist     Full-text available via subscription   (Followers: 8)
Analyst     Full-text available via subscription   (Followers: 38)
Angewandte Chemie     Hybrid Journal   (Followers: 20)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 136)
Annales UMCS, Chemia     Open Access   (Followers: 2)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 1)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 1)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 2)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 6)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 10)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 12)
Anti-Infective Agents     Hybrid Journal   (Followers: 1)
Antiviral Chemistry and Chemotherapy     Full-text available via subscription  
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 4)
Applied Spectroscopy     Full-text available via subscription   (Followers: 16)
Applied Surface Science     Hybrid Journal   (Followers: 22)
Arabian Journal of Chemistry     Full-text available via subscription   (Followers: 6)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 4)
Autophagy     Full-text available via subscription   (Followers: 2)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 6)
Biochemistry     Full-text available via subscription   (Followers: 156)
Biochemistry Insights     Open Access   (Followers: 4)
Biochemistry Research International     Open Access   (Followers: 4)
BioChip Journal     Hybrid Journal   (Followers: 1)
Bioinorganic Chemistry and Applications     Open Access   (Followers: 5)
Bioinspired Materials     Open Access  
Biointerface Research in Applied Chemistry     Open Access   (Followers: 1)
Biointerphases     Open Access  
Biomacromolecules     Full-text available via subscription   (Followers: 18)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 6)
Biomedical Chromatography     Hybrid Journal   (Followers: 7)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 2)
BioNanoScience     Partially Free   (Followers: 4)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 30)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 23)
Bioorganic Chemistry     Hybrid Journal   (Followers: 5)
Biopolymers     Hybrid Journal   (Followers: 16)
Biosensors     Open Access   (Followers: 3)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 3)
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 2)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 13)
C - Journal of Carbon Research     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 3)
Canadian Journal of Chemistry     Full-text available via subscription   (Followers: 6)
Canadian Mineralogist     Full-text available via subscription   (Followers: 2)
Carbohydrate Research     Hybrid Journal   (Followers: 11)
Carbon     Hybrid Journal   (Followers: 74)
Catalysis for Sustainable Energy     Open Access   (Followers: 3)

        1 2 3 4 5 6 | Last

Journal Cover   Carbohydrate Research
  [SJR: 0.654]   [H-I: 83]   [11 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0008-6215 - ISSN (Online) 0008-6215
   Published by Elsevier Homepage  [2800 journals]
  • Understanding reactivity and regioselectivity in Diels–Alder
           reactions of a sugar-derived dienophile bearing two competing EWGs. An
           experimental and computational study
    • Abstract: Publication date: 13 October 2015
      Source:Carbohydrate Research, Volume 415
      Author(s): Germán F. Giri, Ariel M. Sarotti, Rolando A. Spanevello
      The effect of an extra EWG in the reactivity and regioselectivity in Diels–Alder reactions of β-cyanolevoglucosenone and 4 different dienes was studied by a joint computational and experimental study. Conceptual DFT analysis successfully predicted an important enhancement in the reactivity, and correctly anticipated the regioselectivity in the reactions with isoprene. However, this static treatment failed when dealing the regiochemical preference of the reactions involving a substituted anthracene as diene. MPW1K/6-31G* calculations correctly reproduced the experimental observations. Based on the collected data, we found that when dealing with dienes and dienophiles with no clear electronically activated position, the ease of pyramidalization of the interacting atoms dictates the regioselectivity of the DA reaction.
      Graphical abstract image

      PubDate: 2015-08-30T15:17:57Z
       
  • Structure elucidation and biosynthesis gene cluster organization
           of the O–antigen of Escherichia coli O170
    • Abstract: Publication date: Available online 28 August 2015
      Source:Carbohydrate Research
      Author(s): Alexander S. Shashkov, Xi Guo, Andrei V. Perepelov, Andrej Weintraub, Bin Liu, Göran Widmalm, Yuriy A. Knirel
      Enterotoxigenic Escherichia coli are causative agents of diarrhea in humans as well as animals, and E. coli O170 belongs to this virotype. Upon mild acid degradation of the lipopolysaccharide of Escherichia coli O170, the branched O-polysaccharide chain was partially cleaved at β-D-glactofuranosidic linkages to give multiple products, including a linear tetrasaccharide and oligomers thereof. Studies of the acid degradation products and O-deacylated lipopolysaccharide by 1D and 2D 1H and 13C NMR spectroscopy enabled elucidation of the following O-polysaccharide structure: Functions of genes in the O-antigen biosynthesis gene cluster were tentatively assigned and found to be in agreement with the O-polysaccharide structure.
      Graphical abstract image

      PubDate: 2015-08-30T15:17:57Z
       
  • Kinetic characteristics of conformational changes in the hexopyranose
           rings
    • Abstract: Publication date: Available online 28 August 2015
      Source:Carbohydrate Research
      Author(s): Wojciech Plazinski, Mateusz Drach
      The shape of the hexopyranose ring is an important factor which can influence the properties of carbohydrate molecules and affect their biological activity. Due to a limited availability of the experimental data, the conformational rearrangements (puckering) which occur within the pyranose rings are studied extensively by using various computational approaches. Contrary to the basic structural and energetic features characterizing the process of ring flexing, the kinetic and dynamics properties of puckering remain less recognized. We performed the first, molecular dynamics-based, systematic calculations aimed at description of the kinetic characteristics of the conformational changes in the rings of α-d- and β-d-glucopyranose molecules. The rate constants representing particular molecular events which comprise the chair-chair inversion are determined and analyzed in the context of the available experimental data. Furthermore, several various variables (e.g. transmission coefficients) and issues (e.g. memorylessness of the puckering process) are investigated and discussed. As several different parameter sets were used during the study (GROMOS 56A6CARBO, GLYCAM, GROMOS 53A6GLYC), the results provide the conclusion on the capability of the carbohydrate-dedicated force fields to describe the kinetic properties of pyranose ring flexing.


      PubDate: 2015-08-30T15:17:57Z
       
  • Available online Structure of the polysaccharides from the
           lipopolysaccharide of Azospirillum brasilense Jm125A2
    • Abstract: Publication date: Available online 28 August 2015
      Source:Carbohydrate Research
      Author(s): Elena N. Sigida, Yuliya P. Fedonenko, Alexander S. Shashkov, Evelina L. Zdorovenko, Svetlana A. Konnova, Vladimir V. Ignatov, Yuriy A. Knirel
      Two polysaccharides were obtained by mild acid degradation of the lipopolysaccharide of associative nitrogen-fixing bacteria Azospirillum brasilense Jm125A2 isolated from the rhizosphere of a pearl millet. The following structures of the polysaccharides were established by sugar and methylation analyses, Smith degradation, and 1H and 13C NMR spectroscopy: Structure 1 has been reported earlier for a polysaccharide from A. brasilense S17 (Fedonenko YP, Konnova ON, Zdorovenko EL, Konnova SA, Zatonsky GV, Shaskov AS, Ignatov VV, Knirel YA. Carbohydr Res 2008;343:810–6) whereas to our knowledge structure 2 has not been hitherto found in bacterial polysaccharides.


      PubDate: 2015-08-30T15:17:57Z
       
  • High-resolution electrospray mass spectra of hexaethylene glycol connected
           biotinylated HNK-1 antigenic trisaccharide molecular probe and its
           non-sulfated analogue
    • Abstract: Publication date: Available online 28 August 2015
      Source:Carbohydrate Research
      Author(s): Alexander O. Chizhov, Elena V. Sukhova, Elena A. Khatuntseva, Yury E. Tsvetkov, Marina L. Gening, Nikolay E. Nifantiev
      High-resolution electrospray mass spectra in positive and negative ion modes (MS and MS/MS) were measured and described for biotinylated hexaethylene glycol (HEG) connected molecular probes bearing HNK-1 (abbreviation of human natural killer cell-1 epitope) antigenic trisaccharide (1) and its non-sulfated analogue (2). For molecular probe 2, in its CID MS/MS of [M+2Na]2+, unexpected peak at m/z 530.2475 [C22H41N3O8SNa]+ was observed and attributed to the fragmentation of the aglycone at the end of the HEG chain distant from the biotin fragment. No homologous ions having the difference C2H4O smaller than that one were observed. The same cleavage was revealed in negative ion spectra. A similar fragmentation was found for other non-sulfated, biotinylated HEG-spacered molecular probes thus demonstrates this type of fragmentation characteristic for such glycosides.
      Graphical abstract image

      PubDate: 2015-08-30T15:17:57Z
       
  • 13C-NMR Glycosylation Effects in (1→3)-linked Furanosyl-Pyranosides
    • Abstract: Publication date: Available online 28 August 2015
      Source:Carbohydrate Research
      Author(s): Alexey G. Gerbst, Vadim B. Krylov, Dmitry Z. Vinnitskiy, Andrey S. Dmitrenok, Alexander S. Shashkov, Nikolay E. Nifantiev
      Synthesis, theoretical conformational analysis (molecular mechanics and DFT calculations) and NMR spectral data including the 13C-NMR glycosylation effects for six pairs of isomeric furanosyl-(1→3)-pyranosides with different anomeric and absolute configurations of furanosyl units as well as configurations of C2 and C4 in the pyranoside units are described. The determined 13C-NMR glycosylation effects were shown to correlate with the pattern of intramolecular interactions around the inter-unit bonds.
      Graphical abstract image

      PubDate: 2015-08-30T15:17:57Z
       
  • Synthesis of oligo- and polysaccharides by Lactobacillus reuteri 121
           reuteransucrase at high concentrations of sucrose
    • Abstract: Publication date: 23 September 2015
      Source:Carbohydrate Research, Volume 414
      Author(s): Xiangfeng Meng, Justyna M. Dobruchowska, Gerrit J. Gerwig, Johannis P. Kamerling, Lubbert Dijkhuizen
      GTFA, a glucansucrase enzyme of the probiotic bacterium Lactobacillus reuteri 121, is capable of synthesizing an α-glucan polysaccharide with (1→4) and (1→6) linkages from sucrose. With respect to its biosynthesis, the present study has shown that the ratio of oligosaccharide versus polysaccharide synthesized was directly proportional to the concentration of sucrose. It appears that the size distribution of products is kinetically controlled, but the linkage distribution in the polysaccharide material is not changed. At high sucrose concentrations the sucrose isomers leucrose and trehalulose were synthesized, using the accumulated fructose as acceptor, together with 4′- and 6′-α-d-glucosyl-leucrose and 6′-α-d-glucosyl-trehalulose. The finding of an additional branched hexasaccharide demonstrates that the enzyme is able to introduce branch-points already in relatively short oligosaccharides.
      Graphical abstract image

      PubDate: 2015-08-17T19:16:38Z
       
  • Ferrier reaction in a deep eutectic solvent
    • Abstract: Publication date: 13 October 2015
      Source:Carbohydrate Research, Volume 415
      Author(s): Sunil M. Rokade, Prakash M. Bhate
      A mild and efficient synthesis of 2,3-unsaturated sugar derivatives has been achieved by conducting the Ferrier reaction in a deep eutectic solvent (DES). A wide range of alcohols including primary, secondary, benzylic, and sugar-derived primary alcohols can be used. Advantages include good yields, shorter reaction times and recyclability of DES.
      Graphical abstract image

      PubDate: 2015-08-13T19:12:24Z
       
  • Comparison of polysaccharides of Haliotis discus hannai and Volutharpa
           ampullacea perryi by PMP-HPLC-MSn analysis upon acid hydrolysis
    • Abstract: Publication date: 13 October 2015
      Source:Carbohydrate Research, Volume 415
      Author(s): Hongxu Wang, Jun Zhao, Dongmei Li, Chengrong Wen, Haiman Liu, Shuang Song, Beiwei Zhu
      Haliotis discus hannai Ino (Haliotis) is a highly valued marine shellfish, and it is sometimes replaced by another cheaper Gastropoda mollusk, Volutharpa ampullacea perryi (Volutharpa). Polysaccharides from pleopods, viscera and gonads of these two gastropods were compared by analyzing the mono- and di-saccharides in their acid hydrolysates using high performance liquid chromatography-mass spectrometry (HPLC-MSn) after 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatization. Disaccharide analysis revealed the distribution of uronic acid-containing polysaccharides (UACPs) in the biological samples. GlcA-(1→2)-Man, GlcA-(1→3)-GalN, and another disaccharide consisting of a hexuronic acid linked to a hexose were found in the hydrolysates, which indicated the existence of AGSP (abalone gonad sulfated polysaccharide) with the backbone composed of →2)-α-Man(1→4)-β-GlcA(1→ repeating unit, AAP (abalone glycosaminoglycan-like polysaccharide) with the backbone of →3)-GalNAc-(1→2)-GlcA-(1→3)-GalNAc-(1→4)-GlcA-(1→ repeating unit, and unidentified DS1P containing a hexuronic acid linked to a hexose unit, respectively. As shown by extracted ion chromatograms (XICs), AAP was the only UACP found in pleopods of the two gastropods; gonads and viscera of Haliotis contained DS1P and AGSP, while those of Volutharpa contained DS1P, AGSP as well as AAP. Monosaccharides in the acid hydrolysates were demonstrated in XICs by extracting their corresponding PMP derivative quasi-molecular ions one by one, and the results indicated the similar conclusion to the disaccharide analysis. Therefore, it could be concluded that polysaccharides from pleopods of the two gastropods are very similar, while those from their viscera and gonads differ greatly.
      Graphical abstract image

      PubDate: 2015-08-13T19:12:24Z
       
  • The influence of the hexopyranose ring geometry on the conformation of
           glycosidic linkages investigated using molecular dynamics simulations
    • Abstract: Publication date: 13 October 2015
      Source:Carbohydrate Research, Volume 415
      Author(s): Wojciech Plazinski, Mateusz Drach
      The conformation of the carbohydrate molecules is a subject of many theoretical and experimental studies. The different timescales associated with the particular degrees of freedom hinder the progress in both those fields. The present paper reports the results of computational studies aimed at elucidating and characterizing the potential correlations between the two main structural determinants of the carbohydrate structure, i.e. the ring conformation and the orientation of the glycosidic bonds (expressed in terms of the ϕ and ψ glycosidic dihedral angles). The free energy landscapes computed for 16 different oligomers composed of unsubstituted, 1,4-linked hexopyranose residues allowed for a detailed insight into how the ring geometry affects the glycosidic linkage conformation. The factor of main importance appeared to be the local changes of the chain length induced by the ring conformational rearrangements. This effect is important mainly for the carbohydrate chains exploiting the glycosidic bonds of uniform orientation with respect to the ring (i.e. either exclusively axially or exclusively equatorially oriented). The shape of the ring may affect the (ϕ,ψ) free energy maps but only if the population of the alternative ring conformers is relatively high and (at the same time) the presence of such conformers is associated with the significant shifts of the favorable ϕ and ψ values.
      Graphical abstract image

      PubDate: 2015-08-13T19:12:24Z
       
  • Identification, biochemical characterization, and in-vivo expression of
           the intracellular invertase BfrA from the pathogenic parasite Leishmania
           major
    • Abstract: Publication date: 13 October 2015
      Source:Carbohydrate Research, Volume 415
      Author(s): Sorya Belaz, Thibault Rattier, Pierre Lafite, Philippe Moreau, Françoise H. Routier, Florence Robert-Gangneux, Jean-Pierre Gangneux, Richard Daniellou
      The parasitic life cycle of Leishmania includes an extracellular promastigote stage that occurs in the gut of the insect vector. During that period, the sucrose metabolism and more specifically the first glycosidase of this pathway are essential for growth and survival of the parasite. We investigated the expression of the invertase BfrA in the promastigote and amastigote stages of three parasite species representative of the three various clinical forms and of various geographical areas, namely Leishmania major, L. donovani and L. braziliensis. Thereafter, we cloned, overexpressed and biochemically characterized this invertase BfrA from L. major, heterologously expressed in both Escherichia coli and L. tarentolae. For all species, expression levels of BfrA mRNA were correlated to the time of the culture and the parasitic stage (promastigotes > amastigotes). BfrA exhibited no activity when expressed as a glycoprotein in L. tarentolae but proved to be an invertase when not glycosylated, yet owing low sequence homology with other invertases from the same family. Our data suggest that BfrA is an original invertase that is located inside the parasite. It is expressed in both parasitic stages, though to a higher extent in promastigotes. This work provides new insight into the parasite sucrose metabolism.
      Graphical abstract image

      PubDate: 2015-08-13T19:12:24Z
       
  • S-Ribosylhomocysteine analogs containing a [4-thio]ribose ring
    • Abstract: Publication date: 13 October 2015
      Source:Carbohydrate Research, Volume 415
      Author(s): Adam J. Sobczak, Christiane Chbib, Stanislaw F. Wnuk
      The [4-thio]-S-ribosylhomocysteine (SRH) analogs containing substitution of a sulfur atom for the endocyclic oxygen were synthesized by coupling of the 4-thioribose substrates with a thiolate generated from the protected homocysteine. Coupling of the protected 1-deoxy-5-O-mesyl-S-oxo-4-thio-D-ribofuranose with homocysteinate salt gave the C4 epimers of [4-thio]-SRH at the sulfoxide oxidation level lacking a hydroxyl group at anomeric carbon. Treatment of these sulfoxides with BF3⋅Et2O/NaI affected simultaneous reduction to sulfide and global deprotection affording 1-deoxy-4-thio-SRH analog. Treatment of the protected 1-deoxy-S-oxo-4-thio-D-ribofuranose sulfoxide with DAST/SbCl3 resulted in the fluoro-Pummerer rearrangement to give 4-thio-β-D-ribofuranosyl fluoride. Mesylation of the latter at 5-hydroxyl position followed by coupling with homocysteinate salt and subsequent global deprotection with trifluoroacetic acid afforded [4-thio]-SRH thiohemiacetal.
      Graphical abstract image

      PubDate: 2015-08-13T19:12:24Z
       
  • Graphical contents list
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413




      PubDate: 2015-08-09T03:24:33Z
       
  • A mass spectrometric study of the acid-catalysed d-fructose dehydration in
           the gas phase
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Federico Pepi, Andreina Ricci, Stefania Garzoli, Anna Troiani, Chiara Salvitti, Brunella Di Rienzo, Pierluigi Giacomello
      5-hydroxymethylfuraldehyde (5-HMF) and simpler compounds, such as levulinic acid (LA) and glyceraldehyde, are platform molecules produced by the thermal acid-catalyzed dehydration of carbohydrates coming from biomass. Understanding sugar degradation pathways on a molecular level is necessary to increase selectivity, reduce degradation by-products yields and optimize catalytic strategies, fundamental knowledge for the development of a sustainable renewable industry. In this work gaseous protonated d-fructose ions, generated in the ESI source of a triple quadrupole mass spectrometer, were allowed to undergo Collisionally Activated Decomposition (CAD) into the quadrupole collision cell. The ionic intermediates and products derived from protonated d-fructose dehydration were structurally characterized by their fragmentation patterns and the relative water-loss dehydration energies measured by energy-resolved CAD mass spectra. The data were compared with those obtained from protonated d-glucose decomposition in the same experimental conditions. In the gas phase, d-fructose dehydration leads to the formation of a mixed population of isomeric [C6H6O3]H+ ions, whose structures do not correspond exclusively to 5-hydroxymethyl-2-furaldehyde protonated at the more basic aldehydic group.
      Graphical abstract image

      PubDate: 2015-08-09T03:24:33Z
       
  • Editorial board
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413




      PubDate: 2015-08-09T03:24:33Z
       
  • Synthesis of four (4″-, 2″-, 2′-, and 6-) monodeoxy
           analogs of the trisaccharide
           α-d-Glcp-(1→3)-α-d-Manp-(1→2)-α-d-ManpOMe
           recognized by Calreticulin/Calnexin
    • Abstract: Publication date: 23 September 2015
      Source:Carbohydrate Research, Volume 414
      Author(s): Anja Glinschert, Stefan Oscarson
      Routes for efficient synthesis of four (4″-, 2″-, 2′-, and 6-) monodeoxy analogs of the trisaccharide α-d-Glcp-(1→3)-α-d-Manp-(1→2)-α-d-ManpOMe have been developed. For the introduction of the 2′- and 2″-deoxy motifs the most efficient way was to use a 1,2-di-bromo-mannosyl donor in silver triflate-promoted couplings to construct the α-glycosidic linkage followed by reduction of the 2-bromo-function to a 2-deoxy motif at the di- or trisaccharide level. In contrast, the 4″- and 6-deoxy functions were introduced already at the monosaccharide stage. The most challenging part of the syntheses was the stereoselective formation of the non-reducing end cis-α-d-glucosidic linkages. The established α-directing effect of a 3-O-acetyl group in glucosyl donors was explored but the magnitude of the effect was variable and dependent on donor/acceptor structure and nature of promoter and an optimization had to be made for each individual glycosylation.
      Graphical abstract image

      PubDate: 2015-08-09T03:24:33Z
       
  • The O-specific polysaccharide from the marine bacterium Pseudoalteromonas
           agarivorans KMM 255T
    • Abstract: Publication date: 23 September 2015
      Source:Carbohydrate Research, Volume 414
      Author(s): Nadezhda A. Komandrova, Maxim S. Kokoulin, Anatoly I. Kalinovskiy, Svetlana V. Tomshich, Lyudmila A. Romanenko, Victor E. Vaskovsky
      The O-specific polysaccharide was isolated from the lipopolysaccharide of a marine bacterium Pseudoalteromonas agarivorans KMM 255T and studied by chemical methods along with 1H and 13C NMR spectroscopies. The following new structure of the O-specific polysaccharide from P. agarivorans KMM 255T containing 2-acetamido-2-deoxy-d-glucose (d-GlcNAc), d-glucose (d-Glc), d-glucuronic acid (d-GlcA) and two residues of d-galactose (d-Gal) was established:
      Graphical abstract image

      PubDate: 2015-08-09T03:24:33Z
       
  • Docking polysaccharide to proteins that have a Tryptophan box in the
           binding pocket
    • Abstract: Publication date: 23 September 2015
      Source:Carbohydrate Research, Volume 414
      Author(s): Yian Yang, Jiaqiang Qian, Dengming Ming
      Protein–carbohydrate interactions (PCIs) involve a variety of essential biological processes such as cell recognition and migration, metabolism processes and immunological reactions, which are important for securing functions of living organisms. Due to the polysaccharide structural diversity and dynamics flexibility, PCIs can be very difficult for experimental measurement and computer prediction. Here we report a simple method for docking polysaccharide to proteins whose binding pockets have a Tryptophan box. The method samples polysaccharide conformations using constraint conditions imposed by the box, evaluate the conformation energies based on a knowledge-based potential function, and finds the best docking structures using the conventional Monte Carlo simulated annealing technique. We applied the method to dock polysaccharides with 2 to 4 monomers to three carbohydrate-binding proteins, whose pockets have clear aromatic residue-defined binding channels. The predictions found correct carbohydrate binding conformations with atomic RMSD of 1.1–1.6 Å from X-ray crystal structures. The calculation can be performed in ordinary PC and only cost a couple of minutes for a single docking. Our method, when combined with other docking programs, provides a reliable start conformation for further accurate simulation of PCIs.
      Graphical abstract image

      PubDate: 2015-08-09T03:24:33Z
       
  • An efficient synthesis of novel bis-triazole glycoconjugates via a
           three-component condensation as a key reaction
    • Abstract: Publication date: 23 September 2015
      Source:Carbohydrate Research, Volume 414
      Author(s): Jie Cheng, Zhenlong Gu, Caiyu He, Jie Jin, Lijun Wang, Guojun Li, Bei Sun, Hui Wang, Jun Bai
      Novel bis-triazole glycoconjugates were designed and prepared successfully via 5 steps from propargyl per-O-acetyl-β-d-glucoside or xyloside (total yield of 48–53%), after utilizing a three-component condensation of propargyl per-O-acetyl-β-d-glycoside, formaldehyde, and sodium azide as a key step to synthesize 2-hydroxymethyl-2H-1,2,3-triazole glycoconjugates. The developed bis-triazole glycoconjugates would be crucial in antivirus pharmacology and chemical biology.
      Graphical abstract image

      PubDate: 2015-08-09T03:24:33Z
       
  • Synthesis of new saccharide azacrown cryptands
    • Abstract: Publication date: 23 September 2015
      Source:Carbohydrate Research, Volume 414
      Author(s): Michalina Pintal, Florence Charbonniere-Dumarcay, Alain Marsura, Stanisław Porwański
      New cryptands including bis-azacrown and saccharidic moieties in their structure were prepared in several steps by applying Staudinger–aza-Wittig reaction (SAW). Syntheses have been started from cheap, easily available commercial compounds such as D-glucose, D-cellobiose and D-lactose subsequently transformed into their derivatives in fairly good yields (60–65%) and suitable to give desired final cryptands by direct SAW coupling reactions.
      Graphical abstract image

      PubDate: 2015-08-09T03:24:33Z
       
  • l-Fucose-containing arabinogalactan-protein in radish leaves
    • Abstract: Publication date: 13 October 2015
      Source:Carbohydrate Research, Volume 415
      Author(s): Miho Inaba, Takuma Maruyama, Yoshihisa Yoshimi, Toshihisa Kotake, Koji Matsuoka, Tetsuo Koyama, Theodora Tryfona, Paul Dupree, Yoichi Tsumuraya
      The carbohydrate moieties of arabinogalactan-proteins (AGPs) have β-(1→3)-galactan backbones to which side chains of (1→6)-linked β-Gal residues are attached through O-6. Some of these side chains are further substituted with other sugars. We investigated the structure of l-Fuc-containing oligosaccharides released from the carbohydrate moieties of a radish leaf AGP by digestion with α-l-arabinofuranosidase, followed by exo-β-(1→3)-galactanase. We detected a series of neutral β-(1→6)-galactooligosaccharides branching variously at O-3 of the Gal residues, together with corresponding acidic derivatives terminating in 4-O-methyl-GlcA (4-Me-GlcA) or GlcA at the non-reducing terminals. In neutral oligosaccharides with degree of polymerization (dp) mainly higher than 10, l-Fuc groups were attached through l-Ara residues as the sequence, α-l-Fucp-(1→2)-α-l-Araf-(1→. This sequence was verified by isolation of the pentasaccharide α-l-Fuc-(1→2)-α-l-Araf-(1→3)-β-Gal-(1→6)-β-Gal-(1→6)-Gal upon digestion of the higher oligosaccharides with endo-β-(1→6)-galactanase. By contrast, in lower polymerized (predominantly dp 4) acidic oligosaccharides, l-Fuc groups were attached directly at the non-reducing terminals through α-(1→2)-linkages, resulting in the release of the tetrasaccharides, α-l-Fucp-(1→2)-β-GlcA-(1→6)-β-Gal-(1→6)-Gal and α-l-Fucp-(1→2)-β-4-Me-GlcA-(1→6)-β-Gal-(1→6)-Gal. In long acidic oligosaccharides with dp mainly higher than 13, l-Fuc groups localized on branches were attached to the uronic acids directly and/or l-Ara residues as in the neutral oligosaccharides.
      Graphical abstract image

      PubDate: 2015-08-09T03:24:33Z
       
  • Stereoselective synthesis and molecular modeling of chiral cyclopentanes
    • Abstract: Publication date: 13 October 2015
      Source:Carbohydrate Research, Volume 415
      Author(s): Raid J. Abdel-Jalil, Thomas Steinbrecher, Thuraya Al-Harthy, Ahmed Mahal, Osama K. Abou-Zied, Wolfgang Voelter
      The reaction of 3-methyseleno-2-methylselenomethyl-propene with benzyl 2,3-anhydro-4-O-triflyl-β-L-ribopyranoside provides a major convenient enantiomeric product of 1-methylene-(benzyl3,4-dideoxy-α-D-arabinopyranoso)-[3,4-c]-cyclopentane, with benzyl-2,3-anhydro-4-deoxy-4-C-(2-methyl- propen-3-yl)-α-D-lyxopyranoside as a minor product. While the reaction of 3-methyseleno-2-[methylselenomethyl]-propene with benzyl 2,3-anhydro-4-O-triflyl-α-D-ribopyranoside produces a good yield of benzyl-2,3-anhydro-4-deoxy-4-C-(2-methylpropen-3-yl)-α-D-lyxo-pyranoside. Molecular modeling and molecular dynamics simulations indicate that the intermediate in the reaction of the β-L sugar frequently occupies an optimal conformation that leads to the formation of cyclopentane, while the intermediate in the reaction of the α-D sugar has a very small probability. The results point to the dominant role of the β-L sugar intermediate in controlling the cyclopentane formation.
      Graphical abstract image

      PubDate: 2015-08-09T03:24:33Z
       
  • Structure and genetics of the O-antigen of Escherichia coli O169 related
           to the O-antigen of Shigella boydii type 6
    • Abstract: Publication date: 23 September 2015
      Source:Carbohydrate Research, Volume 414
      Author(s): Andrei V. Perepelov, Alexander S. Shashkov, Xi Guo, Andrei V. Filatov, Andrej Weintraub, Göran Widmalm, Yuriy A. Knirel
      The O-polysaccharide (O-antigen) of Escherichia coli O169 was studied by sugar analysis along with 1D and 2D 1H and 13C NMR spectroscopy. The following structure of the branched hexasaccharide repeating unit was established: The O-polysaccharide of E. coli O169 differs from that of Shigella boydii type 6 only in the presence of a side-chain glucose residue. A comparison of the O-antigen biosynthesis gene clusters between the galF to gnd genes in the genomes of the two bacteria revealed their close relationship. The glycosyltransferase gene responsible for the formation of the β-d-Glcp-(1→6)-α-d-Galp linkage in the O-antigen was identified in the gene cluster.
      Graphical abstract image

      PubDate: 2015-07-31T14:40:34Z
       
  • Synthesis of a series of novel heteroglycoclusters and homoglycoclusters
           and the study of their anti-adhesion activities
    • Abstract: Publication date: 23 September 2015
      Source:Carbohydrate Research, Volume 414
      Author(s): Shan Jiang, Shan Niu, Zhi-Hui Zhao, Zhong-Jun Li, Qing Li
      A new series of mixed-type heteroglycoclusters containing mannose and lactose were synthesized. In the synthesis of rigid scaffold of heteroglycocluster, we found that trans-isomer could be prepared stereoselectively by means of Grubbs olefin cross-metathesis reactions. Moreover, sequential acylation using cyclic anhydride as scaffold could give cis-isomer. These two methods may provide complementarity of stereochemistry in heteroglycocluster assembling. The anti-adhesion activities of these compounds were assessed by Surface Plasmon Resonance (SPR) and static state cell-based adhesion assay. These results indicated that the rigid scaffold might not affect the anti-adhesion activities.
      Graphical abstract image

      PubDate: 2015-07-31T14:40:34Z
       
  • Structures and biological activities of cladolosides C3, E1, E2, F1, F2,
           G, H1 and H2, eight triterpene glycosides from the sea cucumber Cladolabes
           schmeltzii with one known and four new carbohydrate chains
    • Abstract: Publication date: 23 September 2015
      Source:Carbohydrate Research, Volume 414
      Author(s): Alexandra S. Silchenko , Anatoly I. Kalinovsky , Sergey A. Avilov , Pelageya V. Andryjaschenko , Pavel S. Dmitrenok , Ekaterina A. Yurchenko , Igor Yu. Dolmatov , Vladimir I. Kalinin
      Eight new nonsulfated triterpene glycosides, cladolosides C3 (1), E1 (2), E2 (3), F1 (4), F2 (5), G (6), H1 (7) and H2 (8) have been isolated from the tropical Indo-West Pacific sea cucumber Cladolabes schmeltzii (Cladolabinae, Sclerodactylidae, Dendrochirotida) collected in the Vietnamese shallow waters. The structures of the glycosides were elucidated by 2D NMR spectroscopy and mass-spectrometry. Glycosides 2, 3, 4, and 5 have pentasaccharide branched carbohydrate moieties and differ from each other by monosaccharide compositions and aglycone structures. At that, glycosides 2 and 3 contain three xylose, one 3-O-methyl-glucose and one quinovose residues, while glycosides 4 and 5 have two quinovose, two xylose and one 3-O-methyl-glucose residues. Compounds 1 and 6–8 are hexaosides differing from each other by aglycone structures and by the fifth monosaccharide residue, which proved to be glucose in cladoloside C3 (1), xylose in cladoloside G (6) and quinovose in cladolosides H1 (7) and H2 (8). The presence of quinovose residue in the fifth position, as in 4, 5, 7 and 8 has never been earlier found in carbohydrate chains of triterpene glycosides from sea cucumbers. The carbohydrate chains with xylose in the fifth position of pentaosides and hexaosides are also very unusual for holothurious glycosides. All the substances demonstrate strong or moderate cytotoxic and hemolytic effects with hexaosides being more active than the corresponding pentaosides. Peculiarities of the biosynthesis and biochemical evolution of glycosides of this type are discussed.
      Graphical abstract image

      PubDate: 2015-07-12T18:47:16Z
       
  • Total synthesis of LewisX using a late-stage crystalline intermediate
    • Abstract: Publication date: 23 September 2015
      Source:Carbohydrate Research, Volume 414
      Author(s): Stefan Munneke , Gavin F. Painter , Graeme J. Gainsford , Bridget L. Stocker , Mattie S.M. Timmer
      Herein, we report on a highly efficient synthesis of a crystalline protected LewisX trisaccharide that was converted to LewisX following global deprotection. The trisaccharide was prepared in a highly convergent synthesis (seven steps, longest linear sequence) and in a 38% overall yield using a strategy that involved the regioselective glycosylation of a GlcNAc acceptor with a galactose thioglycoside donor, followed by fucosylation of the remaining free GlcNAc hydroxyl as key steps. The core trisaccharide also has the potential to be converted to other members of the Type-2 Lewis family of antigens due to the orthogonal nature of the protecting groups employed.
      Graphical abstract image

      PubDate: 2015-07-12T18:47:16Z
       
  • Enzymatic synthesis and characterization of galactosyl monoesters
    • Abstract: Publication date: 23 September 2015
      Source:Carbohydrate Research, Volume 414
      Author(s): Dong An , Xiaohui Zhao , Zhiwen Ye
      Enzyme-catalyzed synthesis of several fatty acyl-amino acid esters based on d-galactose, as well as their chemical evaluation, was performed. These novel galactosyl fatty acyl-amino acid monoesters were synthesized by utilizing lipase from lipozyme TL IM in tert-butanol with d-galactose and fatty acyl-amino acids as starting materials. The products were characterized by 1H NMR, 13C NMR and MS analysis. In addition, their primary physical properties, such as hydrophilic-lipophilic balance (HLB), critical micellar concentration (CMC), solubility in water, maximum surface excess (Γmax), and minimal surface tension (A min) were measured. The experimental results showed that their CMC values are between 5 and 0.4 mM. The HLB values of galactosyl esters 15–17 indicate that they are useful as oil-in-water emulsions or detergents, whereas 18–22 can be employed as water-in-oil emulsifiers or wetting agents.
      Graphical abstract image

      PubDate: 2015-07-12T18:47:16Z
       
  • Core oligosaccharide of Escherichia coli B—the structure required
           for bacteriophage T4 recognition
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Marta Kaszowska , Tomasz Niedziela , Anna Maciejewska , Jolanta Lukasiewicz , Wojciech Jachymek , Czeslaw Lugowski
      The structure of Escherichia coli B strain PCM 1935 core oligosaccharide has been investigated by 1H and 13C NMR spectroscopy, MALDI-TOF MS and ESI MSn. It was concluded that the core oligosaccharide is a pentasaccharide with the following structure: ESI MS/MS analysis revealed that the glycine (a minor component) is linked to the →3,7)-l-α-d-Hepp-(1→ residue.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Structure of the O-specific polysaccharide from the legume endosymbiotic
           bacterium Ochrobactrum cytisi strain ESC1T
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Malgorzata Pac , Iwona Komaniecka , Katarzyna Zamlynska , Anna Turska-Szewczuk , Adam Choma
      The O-specific polysaccharide was obtained from the lipopolysaccharide of the legume-endosymbiotic bacterium Ochrobactrum cytisi strain ESC1T and studied by chemical analyses and 1D and 2D NMR spectroscopy. The polysaccharide was found to have a disaccharide repeating unit containing α-d-fucose and β-N-acetyl-d-galactosamine residues connected via (1→3)-glycosidic bonds, resulting in the following structure: →3)-α-d-Fucp-(1→3)-β-d-GalpNAc-(1→ The d-GalpNAc residue was nonstoichiometrically substituted with a 4-O-methyl group (∼10%) or with a 4,6-O-(1-carboxy)-ethylidene residue (pyruvyl group) (∼10%).
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Structure of the O-specific polysaccharide from a marine bacterium
           Cellulophaga tyrosinoxydans
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): 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 tyrosinoxydans and studied by chemical analyses along with 1H and 13C NMR spectroscopy, including 2D 1H, 1H COSY, TOCSY, ROESY, 1Н, 13С HSQC, HMBC and H2BC experiments. The following new structure of the O-polysaccharide of C. tyrosinoxydans containing l-fucose (Fuc), N-acetyl-d-glucosamine (GlcNAc), 4-acetamido-4,6-dideoxy-d-glucose (Qui4NAc) and two l-rhamnose residues (Rha) was established: .
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Structural elucidation of an asparagine-linked oligosaccharide from the
           hyperthermophilic archaeon, Archaeoglobus fulgidus
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Daisuke Fujinami , James Nyirenda , Shunsuke Matsumoto , Daisuke Kohda
      The genome of the hyperthermophilic archaeon, Archaeoglobus fulgidus, contains three paralogous AglB genes that encode oligosaccharyltransferase (OST) proteins. The OST enzymes catalyze the transfer of an oligosaccharide chain from lipid-linked oligosaccharides (LLO) to asparagine residues in proteins. The detergent-solubilized membrane fractions prepared from cultured A. fulgidus cells contain both OST and LLO. The addition of a peptide containing the glycosylation sequon produced oligosaccharide chains attached to a structurally defined peptide. To facilitate the NMR analysis, the cells were grown in rich medium supplemented with 13 C-glucose, to label the LLOs metabolically. The MS analysis of the glycopeptide revealed that the glucose and galactose residues were nearly fully 13C-labeled, but the mannose residues were fractionally labeled with about 20% efficiency. An immunodetection experiment revealed that the longest AglB paralog (AfAglB-L) was expressed in the membrane fractions under our cell culture conditions, while the other two shorter AglB paralogs (AfAglB-S1 and AfAglB-S2) were not. Thus, the oligosaccharide chain analyzed in this study was the product of AfAglB-L. The N-glycan consists of eight hexose residues, as follows: The α1,3-linked glucose is an optional residue branching from the distal mannose residue. The MS analysis of the minor HPLC peak of the in vitro oligosaccharyl transfer products also revealed an optional sulfate modification on the glucose residue directly linked to the Asn residue. The present data will be useful for structural and functional studies of the N-glycosylation system of A. fulgidus.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Photoinitiated hydrothiolation of pyranoid exo-glycals: the d-galacto and
           d-xylo cases
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): János József , László Juhász , Tünde Zita Illyés , Magdolna Csávás , Anikó Borbás , László Somsák
      Radical-mediated addition reactions of thiols to O-peracetylated exo-galactal and exo-xylal with 2,2-dimethoxy-2-phenylacetophenone as the photoinitiator resulted in high yielding formation of the corresponding β-d-glycopyranosylmethyl-sulfide derivatives (2,6-anhydro-1-deoxy-1-S-substituted-1-thio-alditols) with exclusive regio- and very high stereoselectivity, including disaccharide mimicks with Gly-CH2-S-Gly scaffolds.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Mass spectrometry-based N-linked glycomic profiling as a means for
           tracking pancreatic cancer metastasis
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Hae-Min Park , Mintai Peter Hwang , Yoon-Woo Kim , Kyoung-Jin Kim , Jang Mi Jin , Young Hwan Kim , Yung-Hun Yang , Kwan Hyi Lee , Yun-Gon Kim
      The aberrant glycosylation profile on the surface of cancer cells has been recognized for its potential diagnostic value towards assessing tumor progression. In this study, we initially investigate N-glycan profiles on the surface of normal (HPDE) and cancerous (Capan-1, Panc-1, and MIA PaCa-2) pancreatic cell lines, which are from different sites of pancreatic tumor. The enzymatically deglycosylated total N-glycans are permethylated via a quantitative solid-phase method and then analyzed by using MALDI-TOF MS and MALDI-QIT-TOF MS. We demonstrate that the level of high-mannose type glycans is higher among Capan-1 cells—pancreatic cancer cells that have metastasized to the liver—than that observed among Panc-1 and MIA PaCa-2 cells—pancreatic cancer cells from the pancreas duct head and tail regions, respectively. Furthermore, the relative abundance of highly-branched sialyted N-glycans is significantly up-regulated on Panc-1 and MIA PaCa-2 pancreatic cancer cells compared to that of normal HPDE pancreas cells. Taken together, these results indicate that specific N-glycosylation profile changes in pancreatic cancer cells can be used to not only distinguish between normal and cancerous cells but also provide more information on their location and metastatic potential.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Studies on antioxidative and immunostimulating fucogalactan of the edible
           mushroom Macrolepiota dolichaula
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Surajit Samanta , Ashis K. Nandi , Ipsita K. Sen , Prasenjit Maity , Manabendra Pattanayak , K. Sanjana P. Devi , Somanjana Khatua , Tapas K. Maiti , Krishnendu Acharya , Syed S. Islam
      A water soluble fucogalactan (PS-II) of an average molecular weight ∼1.2×105 Da was isolated from the aqueous extract of an edible mushroom Macrolepiota dolichaula. It was composed of fucose, galactose and 3-O-methyl galactose in a molar ratio of nearly 1:4:1. Structural characterization of PS-II was carried out using total hydrolysis, methylation analysis, Smith degradation, and 1D/2D NMR experiments. These results indicated that the proposed repeating unit of the PS-II had a backbone chain consisting of four (1→6)- linked α-d-Galp residues, one residue methylated at O-3, and another one substituted at O-2 by (1→2)-α-d-Galp residue, which is terminated with a α-l-Fucp moiety. The PS-II exhibited the antioxidant properties in different in vitro test systems, and also showed in vitro macrophage activation in RAW 264.7 cell line as well as splenocyte and thymocyte activation in mouse cell culture medium.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Structure of the neutral capsular polysaccharide of Acinetobacter
           baumannii NIPH146 that carries the KL37 capsule gene cluster
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Nikolay P. Arbatsky , Mikhail M. Shneider , Johanna J. Kenyon , Alexander S. Shashkov , Anastasiya V. Popova , Konstantin A. Miroshnikov , Nikolay V. Volozhantsev , Yuriy A. Knirel
      Capsular polysaccharide (CPS) was isolated from Acinetobacter baumannii NIPH146, and the following structure of branched pentasaccharide repeating unit was established by sugar analyses along with 1D and 2D NMR spectroscopy: In comparison to most other known capsular polysaccharides of A. baumannii, the CPS studied is neutral and lacks any specific monosaccharide component. The synthesis, assembly and export of this structure could be attributed to genes in a novel capsule biosynthesis gene cluster, designated KL37, which was found in the NIPH146 genome. The CPS of A. baumannii NIPH146 shares the α-d-Galp-(1→6)-β-d-Glcp-(1→3)-d-GalpNAc-(1→ trisaccharide fragment with the CPS units of several A. baumannii strains, including ATCC 17978 and LUH 5537 that carry the KL3 and KL22 gene clusters, respectively. KL37 contains two genes for glycosyltransferases that are related to two glycosyltransferase genes present in both KL3 and KL22, and the encoded proteins could be tentatively assigned to linkages between sugars in the CPS repeat.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Triterpenoid saponins from the root bark of Schima superba and their
           cytotoxic activity on B16 melanoma cell line
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Chun Wu , Rong-Liu Zhang , Hong-Yu Li , Chen Hu , Bai-Lian Liu , Yao-Lan Li , Guang-Xiong Zhou
      Eight new oleanane-type triterpenoid saponins, schisusaponins A-H, along with eight known triterpenoid saponins, were isolated from the root bark of Schima superb (Theaceae). Their structures were elucidated on the basis of extensive spectroscopic analyses and chemical methods. The cytotoxicity of the new compounds against B16 melanoma cells was assessed. Among the isolated new saponins, schisusaponins C and E showed more potent effects (with IC50 values of 10.08 and 10.89 μM) than vinblastine (with an IC50 value of 19.48 μM).
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Synthesis of NAG-thiazoline-derived inhibitors for
           β-N-acetyl-d-hexosaminidases
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Hanchu Kong , Wei Chen , Huizhe Lu , Qing Yang , Yanhong Dong , Daoquan Wang , Jianjun Zhang
      β-N-Acetyl-d-hexosaminidases are responsible for the metabolism of glycoconjugates in diverse physiological processes that are important targets for medicine and pesticide development. Fourteen new NAG-thiazoline derivatives were synthesized by cyclization and click reaction using d-glucosamine hydrochloride as the starting material. All the compounds created were characterized by NMR and HRMS spectra. A preliminary bioassay, using four enzymes from two β-N-acetyl-d-hexosaminidase families, showed that most of the compounds synthesized exhibit selective inhibition of GH84 β-N-acetyl-d-hexosaminidase. Among the compounds tested, compounds 5a (IC50=12.6 μM, hOGA) and 5e (IC50=12.5 μM, OfOGA) proved to be a highly selective and potent inhibitor.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Enzymatic synthesis of hyaluronan hybrid urinary trypsin inhibitor
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Ikuko Kakizaki , Ryoki Takahashi , Miho Yanagisawa , Futaba Yoshida , Keiichi Takagaki
      Human urinary trypsin inhibitor is a proteoglycan that has a single low-sulfated chondroitin 4-sulfate chain at the seryl residue in position 10 of the core protein as a glycosaminoglycan moiety, and is used as an anti-inflammatory medicine based on the protease inhibitory activity of the core protein. However, the functions of the glycosaminoglycan moiety have not yet been elucidated in detail. In the present study, the glycosaminoglycan chains of a native urinary trypsin inhibitor were remodeled to hyaluronan chains, with no changes to the core protein, using transglycosylation as a reverse reaction of the hydrolysis of bovine testicular hyaluronidase, and the properties of the hybrid urinary trypsin inhibitor were then analyzed. The trypsin inhibitory activitiy of the hyaluronan hybrid urinary trypsin inhibitor was similar to that of the native type; however, its inhibitory effect on the hydrolysis of hyaluronidase were not as strong as that of the native type. This result demonstrated that the native urinary trypsin inhibitor possessed hyaluronidase inhibitory activity on its chondroitin sulfate chain. The hyaluronan hybrid urinary trypsin inhibitors obtained affinity to a hyaluronan-binding protein not exhibited by the native type. The interactions between the hyaluronan hybrid urinary trypsin inhibitors and phosphatidylcholine (abundant in the outer layer of plasma membrane) were stronger than that of the native type. Hyaluronan hybrid urinary trypsin inhibitors may be useful for investigating the functions of the glycosaminoglycan chains of urinary trypsin inhibitors and hyaluronan, and our hybrid synthesizing method may be used widely in research for future medical applications.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Direct aqueous synthesis of non-protected glycosyl sulfoxides; weak
           inhibitory activity against glycosidases
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Stewart R. Alexander , Andrew J.A. Watson , Antony J. Fairbanks
      A flavinium catalyst, in conjunction with hydrogen peroxide as stoichiometric oxidant, allowed the aqueous conversion of non-protected thioglycosides into the corresponding glycosyl sulfoxides. These glycosyl sulfoxides displayed only very weak inhibitory activity against corresponding glycosidases.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Probing the roles of conserved residues in uridyltransferase domain
           of Escherichia coli K12 GlmU by site-directed mutagenesis
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Shuaishuai Wang , Xuan Fu , Yunpeng Liu , Xian-wei Liu , Lin Wang , Junqiang Fang , Peng George Wang
      N-Acetylglucosamine-1-phosphate uridyltransferase (GlmU) is a bifunctional enzyme that catalyzes both acetyltransfer and uridyltransfer reactions in the prokaryotic UDP-GlcNAc biosynthesis pathway. Our previous study demonstrated that the uridyltransferase domain of GlmU (tGlmU) exhibited a flexible substrate specificity, which could be further applied in unnatural sugar nucleotides preparation. However, the structural basis of tolerating variant substrates is still not clear. Herein, we further investigated the roles of several highly conserved amino acid residues involved in substrate binding and recognition by structure- and sequence-guided site-directed mutagenesis. Out of total 16 mutants designed, tGlmU Q76E mutant which had a novel catalytic activity to convert CTP and GlcNAc-1P into unnatural sugar nucleotide CDP-GlcNAc was identified. Furthermore, tGlmU Y103F and N169R mutants were also investigated to have enhanced uridyltransferase activities compared with wide-type tGlmU.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Synthesis of glycotriazololipids and observations on their self-assembly
           properties
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Mohit Tyagi , K. P. Ravindranathan Kartha
      Various carbohydrate-anchored triazole-linked lipids prepared by solvent-free mechanochemical azide-alkyne click reaction, on analysis by TEM, have been found to spontaneously self-assemble in solvents leading to structures of interesting physicochemical attributes. Interestingly, analogous compounds based on different sugars (e.g., d-glucose, and d-galactose, as also d-lactose) assemble in patterns distinctly different from each other thus reiterating the fact that the structure of the sugar as well as that of the lipid are important factors that determine the size and shape of the supramolecular assembly formed. Besides, the molecular self-assembly was also found to be solvent-as well as temperature-dependent.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • NMR structural determination of unique invertebrate glycosaminoglycans
           endowed with medical properties
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Vitor H. Pomin
      Glycosaminoglycans (GAGs) are sulfated polysaccharides of complex structure endowed with numerous biomedical functions. Although ubiquitously distributed in vertebrates, GAGs can also occur in certain terrestrial or marine invertebrates. Solution nuclear magnetic resonance (NMR) spectroscopy has been the analytical technique mostly employed in structural characterization of GAGs from any source. This review aims at illustrating the application of NMR in structural determination of few representative invertebrate GAG examples of unique structures and endowed with therapeutic actions. They are the holothurian fucosylated chondroitin sulfate, the acharan sulfate isolated from the snail Achatina fulica, the dermatan sulfates with distinct sulfation patterns extracted from ascidian species, the sulfated glucuronic acid-containing heparan sulfate isolated from the gastropode Nodipecten nodosum, and the hybrid heparin/heparan sulfate molecule obtained from the shrimp Litopenaeus vannamei. These invertebrate GAGs exhibit distinct structures when compared to those extracted from mammalian GAGs. The distinct structures of the invertebrate GAGs lead also to different mechanisms of actions as compared to the mammalian GAG standards. Invertebrate GAGs comprise promising therapeutic candidates in fights against diseases. Solution NMR has been playing a pivotal role in this carbohydrate-based drug research, discovery and development.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Direct Mitsunobu monoesterification of N-protected tobramycin competes
           with intramolecular pyrrolidine formation in ester prodrug synthesis
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Sabina Quader , Sue E. Boyd , Ian D. Jenkins , Todd A. Houston
      Unlike the related aminoglycoside neomycin B, N-protected tobramycin can be selectively esterified at its sole, primary hydroxyl group under Mitsunobu conditions. However, depending on the reaction conditions, the reaction can take a different course with intramolecular cyclization of an N-Boc amine leading to formation of an unusual tobramycin pyrrolidine derivative as the major reaction product.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Structure of the O-specific polysaccharide from the deep-sea marine
           bacterium Idiomarina abyssalis КММ 227T containing a
           2-O-sulfate-3-N-(4-hydroxybutanoyl)-3,6-dideoxy-d-glucose
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Maxim S. Kokoulin , Nadezhda A. Komandrova , Anatoly I. Kalinovskiy , Svetlana V. Tomshich , Lyudmila A. Romanenko , Victor V. Vaskovsky
      The O-specific polysaccharide was isolated from the lipopolysaccharide of type strain Idiomarina abyssalis КММ 227T and studied by sugar analysis, Smith degradation, and two-dimensional 1H and 13C NMR spectroscopy including 1H,1H-TOCSY, 1H,1H-COSY, 1H,1H-ROESY, 1H,13C-HSQC, 1H,13C-HMBC, 1H,13C-H2BC and 1H,13C-HSQC-TOCSY experiments. The new structure of the O-specific polysaccharide of I. abyssalis КММ 227T containing 2-O-sulfate-3-N-(4-hydroxybutanoyl)-3,6-dideoxy-d-glucose was established:
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Structure determination of the neutral exopolysaccharide produced by
           Lactobacillus delbrueckii subsp. bulgaricus OLL1073R-1
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Marie-Rose Van Calsteren , Fleur Gagnon , Junko Nishimura , Seiya Makino
      The neutral exopolysaccharide (NPS) of Lactobacillus delbrueckii subsp. bulgaricus strain OLL1073R-1 was purified and characterized. The molecular mass was 5.0×106 g/mol. Sugar and absolute configuration analyses gave the following composition: d-Glc, 1; d-Gal, 1.5. The NPS was also submitted to periodate oxidation followed by borohydride reduction and Smith degradation. Sugar and methylation analyses, 1H and 13C nuclear magnetic resonance, and mass spectrometry of the NPS or of its specifically modified products allowed determining the repeating unit sequence: {2)Glc(α1–3)Glc(β1–3)[Gal(β1–4)]Gal(β1–4)Gal(α1–} n . The structure is compared to that of exopolysaccharides produced by other Lactobacillus bulgaricus strains.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Structural investigation of cell wall polysaccharides of Lactobacillus
           delbrueckii subsp. bulgaricus 17
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): E. Vinogradov , I. Sadovskaya , A. Cornelissen , D. van Sinderen
      Lactobacilli are valuable strains for commercial (functional) food fermentations. Their cell surface-associated polysaccharides (sPSs) possess important functional properties, such as acting as receptors for bacteriophages (bacterial viruses), influencing autolytic characteristics and providing protection against antimicrobial peptides. The current report provides an elaborate molecular description of several surface carbohydrates of Lactobacillus delbrueckii subsp. bulgaricus strain 17. The cell surface of this strain was shown to contain short chain poly(glycerophosphate) teichoic acids and at least two different sPSs, designated here as sPS1 and sPS2, whose chemical structures were examined by 2D nuclear magnetic resonance spectroscopy and methylation analysis. Neutral branched sPS1, extracted with n-butanol, was shown to be composed of hexasaccharide repeating units (-[α-d-Glcp-(1-3)-]-4-β-l-Rhap2OAc-4-β-d-Glcp-[α-d-Galp-(1-3)]-4-α-Rhap-3-α-d-Galp-), while the major component of the TCA-extracted sPS2 was demonstrated to be a linear d-galactan with the repeating unit structure being (-[Gro-3P-(1-6)-]-3-β-Galf-3-α-Galp-2-β-Galf-6-β-Galf-3-β-Galp-).
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Determination of the degree of acetylation and the distribution of acetyl
           groups in chitosan by HPLC analysis of nitrous acid degraded and PMP
           labeled products
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Zhangrun Han , Yangyang Zeng , Hong Lu , Lijuan Zhang
      Chitin is one of the most abundant polysaccharides on earth. It consists of repeating β-1,4 linked N-acetylated glucosamine (A) units. Chitosan is an N-deacetylated product of chitin. Chitosan and its derivatives have broad medical applications as drugs, nutraceuticals, or drug delivery agents. However, a reliable analytical method for quality control of medically used chitosans is still lacking. In current study, nitrous acid was used to cleave all glucosamine residues in chitosan into 2,5-anhydromannose (M) or M at the reducing end of di-, tri-, and oligosaccharides. PMP, i.e. 1-phenyl-3-methyl-5-pyrazolone, was used to label all the Ms. Online UV detection allowed quantification of all M-containing UV peaks whereas online MS analysis directly identified 11 different kinds of mono-, di-, tri-, and oligosaccharides that correlated each oligosaccharide with specific UV peak after HPLC separation. The DA (degree of acetylation) for chitosans was calculated based on the A/(A+M) value derived from the UV data. This newly developed method had several advantages for quality control of chitosan: 1. the experimental procedures were extensively optimized; 2. the reliability of the method was confirmed by online LC-MS analysis; 3. the DA value was obtainable based on the UV data after HPLC analysis, which was comparableto that of 1H NMR and conductometric titration analyses; 4. finally and most importantly, this method could be used to obtain the DA as well as chemical acetylation/deacetylation mechanisms for chitosan by any laboratory equipped with a HPLC and an online UV detector.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Heteroglycan of an edible mushroom Termitomyces clypeatus: structure
           elucidation and antioxidant properties
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Manabendra Pattanayak , Surajit Samanta , Prasenjit Maity , Ipsita K. Sen , Ashis K. Nandi , Dilip K. Manna , Payel Mitra , Krishnendu Acharya , Syed S. Islam
      A water-soluble heteroglycan (PS) of an average molecular weight ∼1.98 ×105 Da was isolated from the aqueous extract of an edible mushroom Termitomyces clypeatus (R. Heim). The structure of the polysaccharide (PS) was established using total hydrolysis, methylation analysis, Smith degradation, and 1D/2D NMR experiments. Total hydrolysis indicated the presence of d-glucose, d-galactose, d-mannose, and l-fucose in a molar ratio of 4.10:1.95:1.0:0.95, respectively. The chemical and NMR analysis indicated the presence of a repeating unit with a backbone consisting of one each of the residues (1→3)-α-d-galactopyranosyl, (1→3)-α-d-mannopyranosyl, (1→3)-α-d-glucopyranosyl, (1→3)-β-d-glucopyranosyl, (1→6)-β-d-glucopyranosyl, and (1→6)-α-d-galactopyranosyl, respectively. The (1→3)-α-d-mannopyranosyl residue was found branched at O-2 with terminal α-l-fucopyranosyl moiety and (1→3)-β-d-glucopyranosyl residue was branched at O-6 with terminal α-d-glucopyranosyl residue. The PS exhibited antioxidant properties.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Modeling of Cooked Starch Digestion Process Using Recombinant Human
           Pancreatic α-Amylase and Maltase-Glucoamylase for in vitro Evaluation
           of α-Glucosidase Inhibitors
    • Abstract: Publication date: Available online 26 June 2015
      Source:Carbohydrate Research
      Author(s): Xiaofang Cao , Chen Zhang , Yangyang Dong , Peng Geng , Fang Bai , Gang Bai
      In human, digestion of cooked starch mainly involves breaking down of α-amylase to α-limit dextrins and small linear malto-oligosaccharides, which are in turn hydrolyzed to glucose by the gut mucosal maltase-glucoamylase (MGAM). Human pancreatic α-amylase (HPA), amino- and carboxyl-terminal portions of MGAM (ntMGAM and ctMGAM) catalyze the hydrolysis of α-D-(1,4) glycosidic linkages in starch, playing a crucial role in the production of glucose in the human lumen. Accordingly, these enzymes are effective drug targets for the treatments of type 2 diabetes and obesity. In this study, a Plackett-Burman based statistical screening procedure was adopted to determine the most critical factors affecting cooked starch digestion by the combination of HPA, ctMGAM and ntMGAM. Six factors were tested and experimental results showed that pH and temperature were the major influencing factors, with optimal pH and temperature at 6.0 and 50°C, respectively. Surprisingly, ntMGAM had no significant contribution to the glucose production from starch digestion compared to the HPA and ctMGAM. The optimal proportion of HPA and ctMGAM in a starch digestion system was further determined by response surface methodology. Results showed a maximum starch digestion (88.05%) within 0.5 hour when used HPA:ctMGAM=1:9 (U). The inhibitory effects of various inhibitors on the cooked starch digestion by HPA1/ctMGAM9 were evaluated by determining their half maximal inhibitory concentration (IC50) values. Acarviostatin II03 showed the highest inhibitory activity, with 67 times higher potency than acarbose. Moreover, acarviostatin II03 could significantly depress postprandial blood glucose levels in mice, better than that by acarbose. These findings suggest that our in vitro enzymatic system can simulate in vivo starch digestion process, and thus can be used to screen and evaluate α-glucosidase inhibitors.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • UDP-hexose 4-epimerases: a view on structure, mechanism and substrate
           specificity
    • Abstract: Publication date: Available online 21 June 2015
      Source:Carbohydrate Research
      Author(s): Koen Beerens , Wim Soetaert , Tom Desmet
      UDP-sugar 4-epimerase (GalE) belongs to the short-chain dehydrogenase/reductase (SDR) superfamily of proteins and is one of enzymes in the Leloir pathway. They have been shown to be important virulence factors in a number of Gram-negative pathogens and to be involved in the biosynthesis of different polysaccharide structures. The metabolic disease type III galactosemia is caused by detrimental mutations in the human GalE. GalE and related enzymes display unusual enzymologic, chemical, and stereochemical properties; including irreversible binding of the cofactor NAD and uridine nucleotide-induced activation of this cofactor. These epimerases have been found active on UDP-hexoses, the N-acetylated and uronic acid forms thereof as well as UDP-pentoses. As they are involved in different pathways and functions, a deeper understanding of the enzymes, and their substrate promiscuity and/or selectivity, could lead to drug and vaccine design as well as antibiotic and probiotic development. This review summarizes the research performed on UDP-sugar 4-epimerases’ structure, mechanism and substrate promiscuity.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2015