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Publisher: Oxford University Press   (Total: 370 journals)

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Showing 1 - 200 of 370 Journals sorted alphabetically
Acta Biochimica et Biophysica Sinica     Hybrid Journal   (Followers: 6, SJR: 0.881, h-index: 38)
Adaptation     Hybrid Journal   (Followers: 8, SJR: 0.111, h-index: 4)
Aesthetic Surgery J.     Hybrid Journal   (Followers: 6, SJR: 1.538, h-index: 35)
African Affairs     Hybrid Journal   (Followers: 57, SJR: 1.512, h-index: 46)
Age and Ageing     Hybrid Journal   (Followers: 81, SJR: 1.611, h-index: 107)
Alcohol and Alcoholism     Hybrid Journal   (Followers: 14, SJR: 0.935, h-index: 80)
American Entomologist     Full-text available via subscription   (Followers: 6)
American Historical Review     Hybrid Journal   (Followers: 126, SJR: 0.652, h-index: 43)
American J. of Agricultural Economics     Hybrid Journal   (Followers: 41, SJR: 1.441, h-index: 77)
American J. of Epidemiology     Hybrid Journal   (Followers: 152, SJR: 3.047, h-index: 201)
American J. of Hypertension     Hybrid Journal   (Followers: 18, SJR: 1.397, h-index: 111)
American J. of Jurisprudence     Hybrid Journal   (Followers: 15)
American journal of legal history     Full-text available via subscription   (Followers: 4, SJR: 0.151, h-index: 7)
American Law and Economics Review     Hybrid Journal   (Followers: 26, SJR: 0.824, h-index: 23)
American Literary History     Hybrid Journal   (Followers: 12, SJR: 0.185, h-index: 22)
Analysis     Hybrid Journal   (Followers: 24)
Annals of Botany     Hybrid Journal   (Followers: 35, SJR: 1.912, h-index: 124)
Annals of Occupational Hygiene     Hybrid Journal   (Followers: 26, SJR: 0.837, h-index: 57)
Annals of Oncology     Hybrid Journal   (Followers: 48, SJR: 4.362, h-index: 173)
Annals of the Entomological Society of America     Full-text available via subscription   (Followers: 8, SJR: 0.642, h-index: 53)
Annals of Work Exposures and Health     Hybrid Journal  
AoB Plants     Open Access   (Followers: 4, SJR: 0.78, h-index: 10)
Applied Economic Perspectives and Policy     Hybrid Journal   (Followers: 19, SJR: 0.884, h-index: 31)
Applied Linguistics     Hybrid Journal   (Followers: 51, SJR: 1.749, h-index: 63)
Applied Mathematics Research eXpress     Hybrid Journal   (Followers: 1, SJR: 0.779, h-index: 11)
Arbitration Intl.     Full-text available via subscription   (Followers: 19)
Arbitration Law Reports and Review     Hybrid Journal   (Followers: 12)
Archives of Clinical Neuropsychology     Hybrid Journal   (Followers: 26, SJR: 0.96, h-index: 71)
Aristotelian Society Supplementary Volume     Hybrid Journal   (Followers: 2, SJR: 0.102, h-index: 20)
Arthropod Management Tests     Hybrid Journal   (Followers: 2)
Astronomy & Geophysics     Hybrid Journal   (Followers: 47, SJR: 0.144, h-index: 15)
Behavioral Ecology     Hybrid Journal   (Followers: 46, SJR: 1.698, h-index: 92)
Bioinformatics     Hybrid Journal   (Followers: 231, SJR: 4.643, h-index: 271)
Biology Methods and Protocols     Hybrid Journal  
Biology of Reproduction     Full-text available via subscription   (Followers: 9, SJR: 1.646, h-index: 149)
Biometrika     Hybrid Journal   (Followers: 19, SJR: 2.801, h-index: 90)
BioScience     Hybrid Journal   (Followers: 28, SJR: 2.374, h-index: 154)
Bioscience Horizons : The National Undergraduate Research J.     Open Access   (Followers: 1, SJR: 0.213, h-index: 9)
Biostatistics     Hybrid Journal   (Followers: 16, SJR: 1.955, h-index: 55)
BJA : British J. of Anaesthesia     Hybrid Journal   (Followers: 135, SJR: 2.314, h-index: 133)
BJA Education     Hybrid Journal   (Followers: 65, SJR: 0.272, h-index: 20)
Brain     Hybrid Journal   (Followers: 61, SJR: 6.097, h-index: 264)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 45, SJR: 4.086, h-index: 73)
Briefings in Functional Genomics     Hybrid Journal   (Followers: 4, SJR: 1.771, h-index: 50)
British J. for the Philosophy of Science     Hybrid Journal   (Followers: 33, SJR: 1.267, h-index: 38)
British J. of Aesthetics     Hybrid Journal   (Followers: 25, SJR: 0.217, h-index: 18)
British J. of Criminology     Hybrid Journal   (Followers: 502, SJR: 1.373, h-index: 62)
British J. of Social Work     Hybrid Journal   (Followers: 80, SJR: 0.771, h-index: 53)
British Medical Bulletin     Hybrid Journal   (Followers: 7, SJR: 1.391, h-index: 84)
British Yearbook of Intl. Law     Hybrid Journal   (Followers: 26)
Bulletin of the London Mathematical Society     Hybrid Journal   (Followers: 3, SJR: 1.474, h-index: 31)
Cambridge J. of Economics     Hybrid Journal   (Followers: 54, SJR: 0.957, h-index: 59)
Cambridge J. of Regions, Economy and Society     Hybrid Journal   (Followers: 9, SJR: 1.067, h-index: 22)
Cambridge Quarterly     Hybrid Journal   (Followers: 10, SJR: 0.1, h-index: 7)
Capital Markets Law J.     Hybrid Journal  
Carcinogenesis     Hybrid Journal   (Followers: 2, SJR: 2.439, h-index: 167)
Cardiovascular Research     Hybrid Journal   (Followers: 11, SJR: 2.897, h-index: 175)
Cerebral Cortex     Hybrid Journal   (Followers: 39, SJR: 4.827, h-index: 192)
CESifo Economic Studies     Hybrid Journal   (Followers: 16, SJR: 0.501, h-index: 19)
Chemical Senses     Hybrid Journal   (Followers: 1, SJR: 1.436, h-index: 76)
Children and Schools     Hybrid Journal   (Followers: 6, SJR: 0.211, h-index: 18)
Chinese J. of Comparative Law     Hybrid Journal   (Followers: 3)
Chinese J. of Intl. Law     Hybrid Journal   (Followers: 19, SJR: 0.737, h-index: 11)
Chinese J. of Intl. Politics     Hybrid Journal   (Followers: 8, SJR: 1.238, h-index: 15)
Christian Bioethics: Non-Ecumenical Studies in Medical Morality     Hybrid Journal   (Followers: 11, SJR: 0.191, h-index: 8)
Classical Receptions J.     Hybrid Journal   (Followers: 17, SJR: 0.1, h-index: 3)
Clinical Infectious Diseases     Hybrid Journal   (Followers: 59, SJR: 4.742, h-index: 261)
Clinical Kidney J.     Open Access   (Followers: 4, SJR: 0.338, h-index: 19)
Community Development J.     Hybrid Journal   (Followers: 24, SJR: 0.47, h-index: 28)
Computer J.     Hybrid Journal   (Followers: 8, SJR: 0.371, h-index: 47)
Conservation Physiology     Open Access   (Followers: 2)
Contemporary Women's Writing     Hybrid Journal   (Followers: 11, SJR: 0.111, h-index: 3)
Contributions to Political Economy     Hybrid Journal   (Followers: 6, SJR: 0.313, h-index: 10)
Critical Values     Full-text available via subscription  
Current Legal Problems     Hybrid Journal   (Followers: 25)
Current Zoology     Full-text available via subscription   (SJR: 0.999, h-index: 20)
Database : The J. of Biological Databases and Curation     Open Access   (Followers: 11, SJR: 1.068, h-index: 24)
Digital Scholarship in the Humanities     Hybrid Journal   (Followers: 12)
Diplomatic History     Hybrid Journal   (Followers: 18, SJR: 0.296, h-index: 22)
DNA Research     Open Access   (Followers: 4, SJR: 2.42, h-index: 77)
Dynamics and Statistics of the Climate System     Open Access   (Followers: 3)
Early Music     Hybrid Journal   (Followers: 13, SJR: 0.124, h-index: 11)
Economic Policy     Hybrid Journal   (Followers: 52, SJR: 2.052, h-index: 52)
ELT J.     Hybrid Journal   (Followers: 25, SJR: 1.26, h-index: 23)
English Historical Review     Hybrid Journal   (Followers: 46, SJR: 0.311, h-index: 10)
English: J. of the English Association     Hybrid Journal   (Followers: 12, SJR: 0.144, h-index: 3)
Environmental Entomology     Full-text available via subscription   (Followers: 11, SJR: 0.791, h-index: 66)
Environmental Epigenetics     Open Access   (Followers: 1)
Environmental History     Hybrid Journal   (Followers: 25, SJR: 0.197, h-index: 25)
EP-Europace     Hybrid Journal   (Followers: 2, SJR: 2.201, h-index: 71)
Epidemiologic Reviews     Hybrid Journal   (Followers: 9, SJR: 3.917, h-index: 81)
ESHRE Monographs     Hybrid Journal  
Essays in Criticism     Hybrid Journal   (Followers: 15, SJR: 0.1, h-index: 6)
European Heart J.     Hybrid Journal   (Followers: 47, SJR: 6.997, h-index: 227)
European Heart J. - Cardiovascular Imaging     Hybrid Journal   (Followers: 9, SJR: 2.044, h-index: 58)
European Heart J. - Cardiovascular Pharmacotherapy     Full-text available via subscription   (Followers: 1)
European Heart J. - Quality of Care and Clinical Outcomes     Hybrid Journal  
European Heart J. Supplements     Hybrid Journal   (Followers: 8, SJR: 0.152, h-index: 31)
European J. of Cardio-Thoracic Surgery     Hybrid Journal   (Followers: 7, SJR: 1.568, h-index: 104)
European J. of Intl. Law     Hybrid Journal   (Followers: 147, SJR: 0.722, h-index: 38)
European J. of Orthodontics     Hybrid Journal   (Followers: 4, SJR: 1.09, h-index: 60)
European J. of Public Health     Hybrid Journal   (Followers: 22, SJR: 1.284, h-index: 64)
European Review of Agricultural Economics     Hybrid Journal   (Followers: 12, SJR: 1.549, h-index: 42)
European Review of Economic History     Hybrid Journal   (Followers: 26, SJR: 0.628, h-index: 24)
European Sociological Review     Hybrid Journal   (Followers: 37, SJR: 2.061, h-index: 53)
Evolution, Medicine, and Public Health     Open Access   (Followers: 11)
Family Practice     Hybrid Journal   (Followers: 13, SJR: 1.048, h-index: 77)
Fems Microbiology Ecology     Hybrid Journal   (Followers: 8, SJR: 1.687, h-index: 115)
Fems Microbiology Letters     Hybrid Journal   (Followers: 20, SJR: 1.126, h-index: 118)
Fems Microbiology Reviews     Hybrid Journal   (Followers: 25, SJR: 7.587, h-index: 150)
Fems Yeast Research     Hybrid Journal   (Followers: 13, SJR: 1.213, h-index: 66)
Foreign Policy Analysis     Hybrid Journal   (Followers: 21, SJR: 0.859, h-index: 10)
Forestry: An Intl. J. of Forest Research     Hybrid Journal   (Followers: 16, SJR: 0.903, h-index: 44)
Forum for Modern Language Studies     Hybrid Journal   (Followers: 6, SJR: 0.108, h-index: 6)
French History     Hybrid Journal   (Followers: 30, SJR: 0.123, h-index: 10)
French Studies     Hybrid Journal   (Followers: 19, SJR: 0.119, h-index: 7)
French Studies Bulletin     Hybrid Journal   (Followers: 10, SJR: 0.102, h-index: 3)
Gastroenterology Report     Open Access   (Followers: 2)
Genome Biology and Evolution     Open Access   (Followers: 10, SJR: 3.22, h-index: 39)
Geophysical J. Intl.     Hybrid Journal   (Followers: 31, SJR: 1.839, h-index: 119)
German History     Hybrid Journal   (Followers: 25, SJR: 0.437, h-index: 13)
GigaScience     Open Access   (Followers: 3)
Global Summitry     Hybrid Journal  
Glycobiology     Hybrid Journal   (Followers: 14, SJR: 1.692, h-index: 101)
Health and Social Work     Hybrid Journal   (Followers: 45, SJR: 0.505, h-index: 40)
Health Education Research     Hybrid Journal   (Followers: 12, SJR: 0.814, h-index: 80)
Health Policy and Planning     Hybrid Journal   (Followers: 21, SJR: 1.628, h-index: 66)
Health Promotion Intl.     Hybrid Journal   (Followers: 20, SJR: 0.664, h-index: 60)
History Workshop J.     Hybrid Journal   (Followers: 27, SJR: 0.313, h-index: 20)
Holocaust and Genocide Studies     Hybrid Journal   (Followers: 23, SJR: 0.115, h-index: 13)
Human Molecular Genetics     Hybrid Journal   (Followers: 9, SJR: 4.288, h-index: 233)
Human Reproduction     Hybrid Journal   (Followers: 76, SJR: 2.271, h-index: 179)
Human Reproduction Update     Hybrid Journal   (Followers: 16, SJR: 4.678, h-index: 128)
Human Rights Law Review     Hybrid Journal   (Followers: 58, SJR: 0.7, h-index: 21)
ICES J. of Marine Science: J. du Conseil     Hybrid Journal   (Followers: 54, SJR: 1.233, h-index: 88)
ICSID Review     Hybrid Journal   (Followers: 9)
ILAR J.     Hybrid Journal   (Followers: 1, SJR: 1.099, h-index: 51)
IMA J. of Applied Mathematics     Hybrid Journal   (SJR: 0.329, h-index: 26)
IMA J. of Management Mathematics     Hybrid Journal   (Followers: 2, SJR: 0.351, h-index: 20)
IMA J. of Mathematical Control and Information     Hybrid Journal   (Followers: 2, SJR: 0.661, h-index: 28)
IMA J. of Numerical Analysis - advance access     Hybrid Journal   (SJR: 2.032, h-index: 44)
Industrial and Corporate Change     Hybrid Journal   (Followers: 8, SJR: 1.37, h-index: 81)
Industrial Law J.     Hybrid Journal   (Followers: 29, SJR: 0.184, h-index: 15)
Information and Inference     Free  
Integrative and Comparative Biology     Hybrid Journal   (Followers: 8, SJR: 1.911, h-index: 90)
Interacting with Computers     Hybrid Journal   (Followers: 10, SJR: 0.529, h-index: 59)
Interactive CardioVascular and Thoracic Surgery     Hybrid Journal   (Followers: 4, SJR: 0.743, h-index: 35)
Intl. Affairs     Hybrid Journal   (Followers: 51, SJR: 1.264, h-index: 53)
Intl. Data Privacy Law     Hybrid Journal   (Followers: 26)
Intl. Health     Hybrid Journal   (Followers: 4, SJR: 0.835, h-index: 15)
Intl. Immunology     Hybrid Journal   (Followers: 3, SJR: 1.613, h-index: 111)
Intl. J. for Quality in Health Care     Hybrid Journal   (Followers: 32, SJR: 1.593, h-index: 69)
Intl. J. of Constitutional Law     Hybrid Journal   (Followers: 59, SJR: 0.613, h-index: 19)
Intl. J. of Epidemiology     Hybrid Journal   (Followers: 122, SJR: 4.381, h-index: 145)
Intl. J. of Law and Information Technology     Hybrid Journal   (Followers: 3, SJR: 0.247, h-index: 8)
Intl. J. of Law, Policy and the Family     Hybrid Journal   (Followers: 28, SJR: 0.307, h-index: 15)
Intl. J. of Lexicography     Hybrid Journal   (Followers: 8, SJR: 0.404, h-index: 18)
Intl. J. of Low-Carbon Technologies     Open Access   (Followers: 1, SJR: 0.457, h-index: 12)
Intl. J. of Neuropsychopharmacology     Open Access   (Followers: 3, SJR: 1.69, h-index: 79)
Intl. J. of Public Opinion Research     Hybrid Journal   (Followers: 8, SJR: 0.906, h-index: 33)
Intl. J. of Refugee Law     Hybrid Journal   (Followers: 32, SJR: 0.231, h-index: 21)
Intl. J. of Transitional Justice     Hybrid Journal   (Followers: 13, SJR: 0.833, h-index: 12)
Intl. Mathematics Research Notices     Hybrid Journal   (Followers: 1, SJR: 2.052, h-index: 42)
Intl. Political Sociology     Hybrid Journal   (Followers: 26, SJR: 1.339, h-index: 19)
Intl. Relations of the Asia-Pacific     Hybrid Journal   (Followers: 17, SJR: 0.539, h-index: 17)
Intl. Studies Perspectives     Hybrid Journal   (Followers: 7, SJR: 0.998, h-index: 28)
Intl. Studies Quarterly     Hybrid Journal   (Followers: 36, SJR: 2.184, h-index: 68)
Intl. Studies Review     Hybrid Journal   (Followers: 17, SJR: 0.783, h-index: 38)
ISLE: Interdisciplinary Studies in Literature and Environment     Hybrid Journal   (Followers: 1, SJR: 0.155, h-index: 4)
ITNOW     Hybrid Journal   (Followers: 2, SJR: 0.102, h-index: 4)
J. of African Economies     Hybrid Journal   (Followers: 15, SJR: 0.647, h-index: 30)
J. of American History     Hybrid Journal   (Followers: 39, SJR: 0.286, h-index: 34)
J. of Analytical Toxicology     Hybrid Journal   (Followers: 13, SJR: 1.038, h-index: 60)
J. of Antimicrobial Chemotherapy     Hybrid Journal   (Followers: 19, SJR: 2.157, h-index: 149)
J. of Antitrust Enforcement     Hybrid Journal   (Followers: 1)
J. of Applied Poultry Research     Hybrid Journal   (Followers: 3, SJR: 0.563, h-index: 43)
J. of Biochemistry     Hybrid Journal   (Followers: 44, SJR: 1.341, h-index: 96)
J. of Chromatographic Science     Hybrid Journal   (Followers: 16, SJR: 0.448, h-index: 42)
J. of Church and State     Hybrid Journal   (Followers: 11, SJR: 0.167, h-index: 11)
J. of Competition Law and Economics     Hybrid Journal   (Followers: 34, SJR: 0.442, h-index: 16)
J. of Complex Networks     Hybrid Journal   (Followers: 1, SJR: 1.165, h-index: 5)
J. of Conflict and Security Law     Hybrid Journal   (Followers: 11, SJR: 0.196, h-index: 15)
J. of Consumer Research     Full-text available via subscription   (Followers: 40, SJR: 4.896, h-index: 121)
J. of Crohn's and Colitis     Hybrid Journal   (Followers: 9, SJR: 1.543, h-index: 37)
J. of Cybersecurity     Hybrid Journal   (Followers: 3)
J. of Deaf Studies and Deaf Education     Hybrid Journal   (Followers: 8, SJR: 0.69, h-index: 36)
J. of Design History     Hybrid Journal   (Followers: 15, SJR: 0.166, h-index: 14)
J. of Economic Entomology     Full-text available via subscription   (Followers: 6, SJR: 0.894, h-index: 76)
J. of Economic Geography     Hybrid Journal   (Followers: 34, SJR: 2.909, h-index: 69)
J. of Environmental Law     Hybrid Journal   (Followers: 23, SJR: 0.457, h-index: 20)
J. of European Competition Law & Practice     Hybrid Journal   (Followers: 19)
J. of Experimental Botany     Hybrid Journal   (Followers: 14, SJR: 2.798, h-index: 163)
J. of Financial Econometrics     Hybrid Journal   (Followers: 21, SJR: 1.314, h-index: 27)
J. of Global Security Studies     Hybrid Journal   (Followers: 2)
J. of Heredity     Hybrid Journal   (Followers: 3, SJR: 1.024, h-index: 76)
J. of Hindu Studies     Hybrid Journal   (Followers: 7, SJR: 0.186, h-index: 3)
J. of Hip Preservation Surgery     Open Access  
J. of Human Rights Practice     Hybrid Journal   (Followers: 20, SJR: 0.399, h-index: 10)
J. of Infectious Diseases     Hybrid Journal   (Followers: 40, SJR: 4, h-index: 209)
J. of Insect Science     Open Access   (Followers: 9, SJR: 0.388, h-index: 31)

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Journal Cover Glycobiology
  [SJR: 1.692]   [H-I: 101]   [14 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0959-6658 - ISSN (Online) 1460-2423
   Published by Oxford University Press Homepage  [370 journals]
  • Glyco-Forum
    • PubDate: 2017-05-05
       
  • GfsA is a β1,5-galactofuranosyltransferase involved in the biosynthesis
           of the galactofuran side chain of fungal-type galactomannan in Aspergillus
           fumigatus
    • Authors: Katafuchi Y; Li Q, Tanaka Y, et al.
      Abstract: <span class="paragraphSection"><div class="boxTitle">Abstract</div>Previously, we reported that GfsA is a novel galactofuranosyltransferase involved in the biosynthesis of <span style="font-style:italic;">O</span>-glycan, the proper maintenance of fungal morphology, the formation of conidia and anti-fungal resistance in <span style="font-style:italic;">Aspergillus nidulans</span> and <span style="font-style:italic;">A. fumigatus</span> (Komachi Y et al., 2013. GfsA encodes a novel galactofuranosyltransferase involved in biosynthesis of galactofuranose antigen of O-glycan in Aspergillus nidulans and Aspergillus fumigatus. <span style="font-style:italic;">Mol. Microbiol.</span> 90:1054–1073). In the present paper, to gain an in depth-understanding of the enzymatic functions of GfsA in <span style="font-style:italic;">A. fumigatus</span> (AfGfsA), we established an in vitro assay to measure galactofuranosyltransferase activity using purified AfGfsA, UDP-α-<span style="text-transform:lowercase;font-variant:small-caps;">d</span>-galactofuranose as a sugar donor, and <span style="font-style:italic;">p</span>-nitrophenyl-β-<span style="text-transform:lowercase;font-variant:small-caps;">d</span>-galactofuranoside as an acceptor substrate. LC/MS, <sup>1</sup>H-NMR and methylation analyses of the enzymatic products of AfGfsA revealed that this protein has the ability to transfer galactofuranose to the C-5 position of the β-galactofuranose residue via a β-linkage. AfGfsA requires a divalent cation of manganese for maximal activity and consumes UDP-α-<span style="text-transform:lowercase;font-variant:small-caps;">d</span>-galactofuranose as a sugar donor. Its optimal pH range is 6.5–7.5 and its optimal temperature range is 20–30°C. <sup>1</sup>H-NMR, <sup>13</sup>C-NMR and methylation analyses of fungal-type galactomannan extracted from the ∆<span style="font-style:italic;">AfgfsA</span> strain revealed that AfGfsA is responsible for the biosynthesis of β1,5-galactofuranose in the galactofuran side chain of fungal-type galactomannan. Based on these results, we conclude that AfGfsA acts as a UDP-α-<span style="text-transform:lowercase;font-variant:small-caps;">d</span>-galactofuranose: β-<span style="text-transform:lowercase;font-variant:small-caps;">d</span>-galactofuranoside β1,5-galactofuranosyltransferase in the biosynthetic pathway of galactomannans.</span>
      PubDate: 2017-04-21
       
  • Characterization of the single-subunit oligosaccharyltransferase STT3A
           from Trypanosoma brucei using synthetic peptides and lipid-linked
           oligosaccharide analogs
    • Authors: Ramírez A; Boilevin J, Biswas R, et al.
      Abstract: <span class="paragraphSection"><div class="boxTitle">Abstract</div>The initial transfer of a complex glycan in protein <span style="font-style:italic;">N</span>-glycosylation is catalyzed by oligosaccharyltransferase (OST), which is generally a multisubunit membrane protein complex in the endoplasmic reticulum but a single-subunit enzyme (ssOST) in some protists. To investigate the reaction mechanism of ssOST, we recombinantly expressed, purified and characterized the STT3A protein from <span style="font-style:italic;">Trypanosoma brucei</span> (TbSTT3A). We analyzed the in vitro activity of TbSTT3A by synthesizing fluorescently labeled acceptor peptides as well as lipid-linked oligosaccharide (LLO) analogs containing a chitobiose moiety coupled to oligoprenyl carriers of distinct lengths (C<sub>10</sub>, C<sub>15</sub>, C<sub>20</sub> and C<sub>25</sub>) and with different double bond stereochemistry. We found that in addition to proline, charged residues at the +1 position of the sequon inhibited glycan transfer. An acidic residue at the −2 position significantly increased catalytic turnover but was not essential, in contrast to the bacterial OST. While all synthetic LLO analogs were processed by TbSTT3A, the length of the polyprenyl tail, but not the stereochemistry of the double bonds, determined their apparent affinity. We also synthesized phosphonate analogs of the LLOs, which were found to be competitive inhibitors of the reaction, although with lower apparent affinity to TbSTT3A than the active pyrophosphate analogs.</span>
      PubDate: 2017-03-16
       
  • A pseudaminic acid or a legionaminic acid derivative transferase is
           strain-specifically implicated in the general protein O -glycosylation
           system of the periodontal pathogen Tannerella forsythia
    • Authors: Tomek M; Janesch B, Maresch D, et al.
      Abstract: <span class="paragraphSection"><div class="boxTitle">Abstract</div>The occurrence of nonulosonic acids in bacteria is wide-spread and linked to pathogenicity. However, the knowledge of cognate nonulosonic acid transferases is scarce. In the periodontopathogen <span style="font-style:italic;">Tannerella forsythia</span>, several proposed virulence factors carry strain-specifically either a pseudaminic or a legionaminic acid derivative as terminal sugar on an otherwise structurally identical, protein-bound oligosaccharide. This study aims to shed light on the transfer of either nonulosonic acid derivative on a proximal <span style="font-style:italic;">N</span>-acetylmannosaminuronic acid residue within the <span style="font-style:italic;">O</span>-glycan structure, exemplified with the bacterium's abundant S-layer glycoproteins. Bioinformatic analyses provided the candidate genes <span style="font-style:italic;">Tanf_01245</span> (strain ATCC 43037) and <span style="font-style:italic;">TFUB4_00887</span> (strain UB4), encoding a putative pseudaminic and a legionaminic acid derivative transferase, respectively. These transferases have identical C-termini and contain motifs typical of glycosyltransferases (DXD) and bacterial sialyltransferases (D/E-D/E-G and HP). They share homology to type B glycosyltransferases and TagB, an enzyme catalyzing glycerol transfer to an <span style="font-style:italic;">N</span>-acetylmannosamine residue in teichoic acid biosynthesis. Analysis of a cellular pool of nucleotide-activated sugars confirmed the presence of the CMP-activated nonulosonic acid derivatives, which are most likely serving as substrates for the corresponding transferase. Single gene knock-out mutants targeted at either transferase were analyzed for S-layer <span style="font-style:italic;">O</span>-glycan composition by ESI-MS, confirming the loss of the nonulosonic acid derivative. Cross-complementation of the mutants with the nonnative nonulosonic acid transferase was not successful indicating high stringency of the enzymes. This study identified plausible candidates for a pseudaminic and a legionaminic acid derivative transferase; these may serve as valuable tools for engineering of novel sialoglycoconjugates.</span>
      PubDate: 2017-03-16
       
  • Discoveries of the structures of sialic acid and CMP-sialic acid
           (1957–1960): a letter from Saul Roseman
    • Authors: Schnaar R; Lee Y.
      Abstract: <span class="paragraphSection"><div class="boxTitle">Abstract</div>Sialic acids have a special place in vertebrate glycobiology, where they constitute the dominant terminal saccharides on many cell surface glycans. From early studies that identified sialoglycans as receptors for important pathogens and toxins to more recent discoveries of sialic acid-binding proteins essential for immune system (and other) functions in humans, sialic acids and sialoglycans have become cornerstones in understanding vertebrate glycobiology and pathology. During a remarkable 3-year period in the late 1950s, a newly minted postdoctoral fellow (Donald G. Comb) and his young mentor (Saul Roseman) made a surprising series of discoveries that put sialic acid research on sound chemical and biochemical footing. A detailed personal letter written by Dr. Roseman that describes this period of intense sialic acid discovery, complete with inserted figures, was given to one of us (Y.C.L.) several years later. The text and figures of this letter provide a look back at the enthusiasm, rigor and serendipity that led to their important findings through the eyes of one of the key figures in sialic acid research.</span>
      PubDate: 2017-03-15
       
  • Hyaluronan synthase assembles hyaluronan on a [GlcNAc(β1,4)] n
           -GlcNAc(α1→)UDP primer and hyaluronan retains this residual chitin
           oligomer as a cap at the nonreducing end
    • Authors: Weigel P; Baggenstoss B, Washburn J.
      Abstract: <span class="paragraphSection"><div class="boxTitle">Abstract</div>Class I hyaluronan synthases (HAS) assemble [GlcNAc(β1,4)GlcUA(β1,3)]<span style="font-style:italic;">n</span>-UDP at the reducing end and also make chitin. <span style="font-style:italic;">Streptococcus equisimilis</span> HAS (SeHAS) also synthesizes chitin-UDP oligosaccharides, (GlcNAc-β1,4)<sub><span style="font-style:italic;">n</span></sub>-GlcNAc(α1→)UDP (Weigel et al. 2015). Here we determined if HAS uses chitin-UDPs as primers to initiate HA synthesis, leaving the non-HA primer at the nonreducing (NR) end. HA made by SeHAS membranes was purified, digested with streptomyces lyase, and hydrophobic oligomers were enriched by solid phase extraction and analyzed by MALDI-TOF MS. Jack bean hexosaminidase (JBH) and MS/MS were used to analyze 19 <span style="font-style:italic;">m/z</span> species of possible G<span style="font-style:italic;">n</span>H<span style="font-style:italic;">n</span> ions with clustered GlcNAc (G) residues attached to disaccharide units (H): (GlcNAcβ1,4)<sub>2–5</sub>[GlcUA(β1,3)GlcNAc]<sub>2–6</sub>. JBH digestion sequentially removed GlcNAc from the NR-end of G<span style="font-style:italic;">n</span>H<span style="font-style:italic;">n</span> oligomers, producing successively smaller G<span style="font-style:italic;">n</span>H<sub>2–3</sub> series members. Since lyase releases dehydro-oligos (dH<span style="font-style:italic;">n</span>; M<sup>−18</sup>), only the unique NR-end oligo lacks dehydro-GlcUA. H<span style="font-style:italic;">n</span> oligomers were undetectable in lyase digests, whereas JBH treatment created new H<sub>2–6</sub><span style="font-style:italic;">m/z</span> peaks (i.e. HA tetra- through dodeca-oligomers). MS/MS of larger G<span style="font-style:italic;">n</span>H<span style="font-style:italic;">n</span> species produced chitin (2–5 GlcNAcs), HA oligomers and multiple smaller series members with fewer GlcNAcs. All NR-ends (97%) started with GlcNAc, as a chitin trimer (three GlcNAcs), indicating that GlcNAc(β1,4)<sub>2</sub>GlcNAc(α1→)-UDP may be optimal for initiation of HA synthesis. Also, HA made by live <span style="font-style:italic;">S. pyogenes</span> cells had G<sub>4</sub>H<span style="font-style:italic;">n</span> chitin-oligo NR-ends. We conclude that chitin-UDP functions in vitro and in live cells as a primer to initiate synthesis of all HA chains and these primers remain at the NR-ends of HA chains as residual chitin caps [(GlcNAc-β1,4)<sub>3–4</sub>].</span>
      PubDate: 2017-03-02
       
  • Non-reducing end labeling of heparan sulfate via click chemistry and a
           high throughput ELISA assay for heparanase
    • Authors: Wu Z; Huang X, Ethen C, et al.
      Abstract: <span class="paragraphSection"><div class="boxTitle">Abstract</div>Heparan sulfate (HS) is a linear polysaccharide found in the extracellular matrix (ECM) and on the cell membrane. It plays numerous roles in cellular events, including cell growth, migration and differentiation through binding to various growth factors, cytokines and other ECM proteins. Heparanase (HPSE) is an endoglycosidase that cleaves HS in the ECM and cell membrane. By degrading HS, HPSE not only alters the integrity of the ECM but also releases growth factors and angiogenic factors bound to HS chains, therefore, changes various cellular activities, including cell mobility that is critical for cancer metastasis. Accordingly, HPSE is an ideal drug target for cancer therapeutics. Here, we describe a method for non-reducing end labeling of HS via click chemistry (CC), and further use it in a novel HPSE assay. HS chains on a recombinant human syndecan-4 are first labeled at their non-reducing ends with GlcNAz using dimeric HS polymerase EXT1/EXT2. The labeled sample is then biotinylated through CC, immobilized on a multi-well plate and detected with ELISA. HPSE digestion of the biotinylated sample removes the label and, therefore, reduces the signal in ELISA assay. Non-reducing end labeling avoids the interference in an HPSE reaction caused by any internal labeling of HS. The assay is very sensitive with only 2.5 ng of labeled syndecan-4 needed in each reaction. The assay is also highly reproducible with a <span style="font-style:italic;">Z</span>’ > 0.6. Overall, this new method is suitable for high-throughput drug screening on HPSE.</span>
      PubDate: 2017-02-06
       
  • Distribution of the O -acetyl groups and β-galactofuranose units in
           galactoxylomannans of the opportunistic fungus Cryptococcus neoformans *
    • Authors: Previato J; Vinogradov E, Maes E, et al.
      Abstract: <span class="paragraphSection"><div class="boxTitle">Abstract</div>Galactoxylomannans (GalXMs) are a mixture of neutral and acidic capsular polysaccharides produced by the opportunistic fungus <span style="font-style:italic;">Cryptococcus neoformans</span> that exhibit potent suppressive effects on the host immune system. Previous studies describing the chemical structure of <span style="font-style:italic;">C. neoformans</span> GalXMs have reported species without <span style="font-style:italic;">O</span>-acetyl substituents. Herein we describe that <span style="font-style:italic;">C. neoformans</span> grown in capsule-inducing medium produces highly <span style="font-style:italic;">O</span>-acetylated GalXMs. The location of the <span style="font-style:italic;">O</span>-acetyl groups was determined by nuclear magnetic resonance (NMR) spectroscopy. In the neutral GalXM (NGalXM), 80% of 3-linked mannose (α-Man<span style="font-style:italic;">p</span>) residues present in side chains are acetylated at the <span style="font-style:italic;">O</span>-2 position. In the acidic GalXM also termed glucuronoxylomannogalactan (GXMGal), 85% of the 3-linked α-Man<span style="font-style:italic;">p</span> residues are acetylated either in the <span style="font-style:italic;">O</span>-2 (75%) or in the <span style="font-style:italic;">O</span>-6 (25%) position, but <span style="font-style:italic;">O</span>-acetyl groups are not present at both positions simultaneously. In addition, NMR spectroscopy and methylation analysis showed that β-galactofuranose (β-Gal<span style="font-style:italic;">f</span>) units are linked to <span style="font-style:italic;">O</span>-2 and <span style="font-style:italic;">O</span>-3 positions of nonbranched α-galactopyranose (α-Gal<span style="font-style:italic;">p</span>) units present in the GalXMs backbone chain. These findings highlight new structural features of <span style="font-style:italic;">C. neoformans</span> GalXMs. Among these features, the high degree of <span style="font-style:italic;">O</span>-acetylation is of particular interest, since <span style="font-style:italic;">O</span>-acetyl group-containing polysaccharides are known to possess a range of immunobiological activities.</span>
      PubDate: 2017-01-23
       
 
 
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