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Gao J, Huang X. Recent advances on glycosyltransferases involved in the biosynthesis of the proteoglycan linkage region. Adv Carbohydr Chem Biochem 2021; 80:95-119. [PMID: 34872657 DOI: 10.1016/bs.accb.2021.10.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Proteoglycans (PGs) are an essential family of glycoproteins, which can play roles in many important biological events including cell proliferation, cancer development, and pathogen infections. Proteoglycans consist of a core protein with one or multiple glycosaminoglycan (GAG) chains, which are covalently attached to serine residues of serine-glycine dipeptide within the core protein through a common tetrasaccharide linkage. In the past three decades, four key glycosyl transferases involved in the biosynthesis of PG linkage have been discovered and investigated. This review aims to provide an overview on progress made on these four enzymes, with foci on enzyme expression/purification, substrate specificity, activity determination, product characterization, and structure-activity relationship analysis.
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Affiliation(s)
- Jia Gao
- Department of Chemistry, Michigan State University, East Lansing, MI, United States; Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, United States
| | - Xuefei Huang
- Department of Chemistry, Michigan State University, East Lansing, MI, United States; Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, United States; Department of Biomedical Engineering, Michigan State University, East Lansing, MI, United States.
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2
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Mastio R, Willén D, Söderlund Z, Westergren-Thorsson G, Manner S, Tykesson E, Ellervik U. Fluorescently labeled xylosides offer insight into the biosynthetic pathways of glycosaminoglycans. RSC Adv 2021; 11:38283-38292. [PMID: 35498069 PMCID: PMC9044174 DOI: 10.1039/d1ra06320k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 11/22/2021] [Indexed: 11/21/2022] Open
Abstract
Five novel xylosides tagged with the fluorescent probe Pacific Blue™ were synthesized and found to act as substrates for β4GalT7, a bottleneck enzyme in the biosynthetic pathways leading to glycosaminoglycans. By confocal microscopy of A549 cells, we showed that the xylosides were taken up by the cells, but did not enter the Golgi apparatus where most of the glycosaminoglycan biosynthesis occurs. Instead, after a possible double galactosylation by β4GalT7 and β3GalT6, the biosynthesis was terminated. We hypothesize this is due to the charge of the fluorescent probe, which is required for fluorescent ability and stability under physiological conditions. Fluorescently labeled xylosides are taken up by cells and initiate priming of labeled GAG chains of various length.![]()
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Affiliation(s)
- Roberto Mastio
- Centre for Analysis and Synthesis, Centre for Chemistry and Chemical Engineering, Lund University, P. O. Box 124, SE-221 00 Lund, Sweden
| | - Daniel Willén
- Centre for Analysis and Synthesis, Centre for Chemistry and Chemical Engineering, Lund University, P. O. Box 124, SE-221 00 Lund, Sweden
| | - Zackarias Söderlund
- Department of Experimental Medical Science, Lund University, P. O. Box 117, SE-221 00 Lund, Sweden
| | | | - Sophie Manner
- Centre for Analysis and Synthesis, Centre for Chemistry and Chemical Engineering, Lund University, P. O. Box 124, SE-221 00 Lund, Sweden
| | - Emil Tykesson
- Department of Experimental Medical Science, Lund University, P. O. Box 117, SE-221 00 Lund, Sweden
| | - Ulf Ellervik
- Centre for Analysis and Synthesis, Centre for Chemistry and Chemical Engineering, Lund University, P. O. Box 124, SE-221 00 Lund, Sweden
- Department of Experimental Medical Science, Lund University, P. O. Box 117, SE-221 00 Lund, Sweden
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3
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Rokhum L, Bez G. Recent Application of Polystyrene-supported Triphenylphosphine in Solid-Phase Organic Synthesis. CURR ORG CHEM 2019. [DOI: 10.2174/1385272822666181026115752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent years have witnessed a fast development of solid phase synthetic pathways, a variety of solid-supported reagent and its applications in diverse synthetic strategies and pharmaceutical applicability’s. Polymer-supported triphenylphosphine is getting a lot of applications owing to the speed and simplicity in the process. Furthermore, ease of recyclability and reuse of polymer-supported triphenylphosphine added its advantages. This review covers a wide range of useful organic transformations which are accomplished using cross-linked polystyrene-supported triphenylphosphine with the aim of giving renewed interest in the field of organic and medicinal-combinatorial chemistry.
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Affiliation(s)
- Lalthazuala Rokhum
- Department of Chemistry, National Institute of Technology, Silchar-788010, India
| | - Ghanashyam Bez
- Department of Chemistry, North Eastern Hill University, Shillong-793022, India
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4
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Dahbi S, Jacquinet JC, Bertin-Jung I, Robert A, Ramalanjaona N, Gulberti S, Fournel-Gigleux S, Lopin-Bon C. Synthesis of a library of variously modified 4-methylumbelliferyl xylosides and a structure-activity study of human β4GalT7. Org Biomol Chem 2017; 15:9653-9669. [PMID: 29116283 DOI: 10.1039/c7ob02530k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Proteoglycans (PGs) are complex macromolecules that are composed of glycosaminoglycan (GAG) chains covalently attached to a core protein through a tetrasaccharide linker. The biosynthesis of PGs is complex and involves a large number of glycosyltranferases. Here we present a structure-activity study of human β4GalT7, which transfers the first Gal residue onto a xyloside moiety of the linkage region. An efficient and regiocontrolled synthesis of a library of modified analogs of 4-methylumbelliferyl xyloside (XylMU) is reported herein. Hydroxyl groups at the position C-2, C-3 or C-4 have been epimerized and/or replaced by a hydrogen or a fluorine, while the anomeric oxygen was replaced by either a sulfur or a sulfone. The effect of these compounds on human β4GalT7 activity in vitro and on GAG biosynthesis in cellulo was then evaluated.
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Affiliation(s)
- Samir Dahbi
- Univ. Orléans et CNRS, ICOA, UMR 7311, F-45067 Orléans, France.
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5
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Mencio CP, My Tran V, Quintero MV, Koketsu M, Goller F, Kuberan B. Regulation of glycosaminoglycan biogenesis is critical for sensitive-period-dependent vocal ontogeny. Dev Neurobiol 2017; 77:1401-1412. [PMID: 29055099 DOI: 10.1002/dneu.22547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/30/2017] [Accepted: 10/16/2017] [Indexed: 11/11/2022]
Abstract
In the brain, the extracellular matrix (ECM) plays a central role during neural development and thus modulates critical-period regulated behavioral ontogeny. The major components of the ECM are glycosaminoglycans (GAGs) including chondroitin sulfate (CS). However, the specific roles of GAGs in behavioral development are largely unknown. It has been shown that xylosides affect the biological functions of GAGs through modulating GAG biosynthesis. Particularly, xylosides affect GAG biosynthesis through priming of GAG chains (priming activity), competing with endogenous core proteins that carry GAG initiation sites (decoy activity), or both. Using birdsong as our model, we investigated, for the first time, how xyloside-mediated modulation of GAG biogenesis affects song development. Xylosides infused into motor cortex of juvenile birds alter song development by specifically affecting ontogeny of the stereotyped sequence rather than the acoustic structure of syllables. Further analyses reveal that observed changes can be attributed to the priming activity rather than the decoy activity of xylosides. Collectively, these results suggest that regulation of GAG biogenesis through chemical biology approaches may allow promising therapeutic interventions of critical-period-dependent central nervous system plasticity. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 1401-1412, 2017.
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Affiliation(s)
- Caitlin P Mencio
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, Utah, 84112
| | - Vy My Tran
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, 84112
| | - Maritza V Quintero
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, 84112
| | - Mamoru Koketsu
- Department of Chemistry and Biomolecular Science, Gifu University, Gifu, 501-1193, Japan
| | - Franz Goller
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, Utah, 84112.,Department of Biology, University of Utah, Salt Lake City, Utah, 84112
| | - Balagurunathan Kuberan
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, Utah, 84112.,Department of Biology, University of Utah, Salt Lake City, Utah, 84112
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6
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Otsuka Y, Sato T. Saccharide Primers Comprising Xylosyl-Serine Primed Phosphorylated Oligosaccharides Act as Intermediates in Glycosaminoglycan Biosynthesis. ACS OMEGA 2017; 2:3110-3122. [PMID: 30023684 PMCID: PMC6044892 DOI: 10.1021/acsomega.7b00073] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 05/22/2017] [Indexed: 05/29/2023]
Abstract
β-Xylosides have been used as an artificial initiator of glycosaminoglycan (GAG) biosynthesis to investigate its mechanism and to obtain these oligosaccharides. In GAG biosynthesis, phosphorylation on the xylose residue is a crucial step. However, little attention has been paid to phosphorylated oligosaccharides obtained from β-xylosides. In a previous study, we demonstrated that a novel β-xyloside, N-lauryl-O-β-xyloyranosyl-serinamide (Xyl-Ser-C12), had excellent GAG-type oligosaccharide priming ability, whereas phosphorylated oligosaccharides were not found in the primed oligosaccharides. This study examines the potential of Xyl-Ser-C12 and three of its derivatives for use as a probe to investigate the GAG biosynthesis mechanism. Glycosylated products were obtained by incubation of the β-xylosides in normal human dermal fibroblast cells and compared by liquid chromatography-electrospray ionization-mass spectrometry. By the optimized method to detect phosphorylated products, Xyl-Ser-C12 was demonstrated to prime not only GAG-type oligosaccharides but also a variety of xylose-phosphorylated products. Among the synthesized β-xylosides, those consisting of xylosyl-serine primed large amounts of phosphorylated and GAG-type oligosaccharides, whereas the others primed sialyloligosaccharides mainly. The majority of the phosphorylated products were considered to be GAG intermediates, which are less observed in nature. To our best knowledge, this is the first report showing that the amino acid residues around the Xyl attachment position strongly affect the phosphorylation efficiency and GAG chain-priming ability of β-xylosides. This study leads to the possibility of the use of β-xyloside as a probe to observe the Xyl phosphorylation process during GAG biosynthesis and investigate comparative glycosaminoglycomics between different cells.
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Affiliation(s)
- Yuya Otsuka
- Central Research
Laboratories, Seikagaku Corporation, 1253, Tateno 3-chome, Higashiyamato-shi, Tokyo 207-0021, Japan
- Department
of Biosciences and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohokuku, Yokohama, Kanagawa 223-8522, Japan
| | - Toshinori Sato
- Department
of Biosciences and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohokuku, Yokohama, Kanagawa 223-8522, Japan
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7
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Brindani N, Mena P, Calani L, Benzie I, Choi SW, Brighenti F, Zanardi F, Curti C, Del Rio D. Synthetic and analytical strategies for the quantification of phenyl-γ-valerolactone conjugated metabolites in human urine. Mol Nutr Food Res 2017; 61. [DOI: 10.1002/mnfr.201700077] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 01/26/2023]
Affiliation(s)
- Nicoletta Brindani
- Human Nutrition Unit; Department of Food & Drug; University of Parma; Parma Italy
- Department of Food & Drug; University of Parma; Parma Italy
| | - Pedro Mena
- Human Nutrition Unit; Department of Food & Drug; University of Parma; Parma Italy
| | - Luca Calani
- Human Nutrition Unit; Department of Food & Drug; University of Parma; Parma Italy
| | - Iris Benzie
- The Department of Health Technology and Informatics; Hong Kong Polytechnic University; Hung Hom Kowloon Hong Kong
| | - Siu-Wai Choi
- The Department of Health Technology and Informatics; Hong Kong Polytechnic University; Hung Hom Kowloon Hong Kong
| | - Furio Brighenti
- Human Nutrition Unit; Department of Food & Drug; University of Parma; Parma Italy
| | - Franca Zanardi
- Department of Food & Drug; University of Parma; Parma Italy
| | - Claudio Curti
- Department of Food & Drug; University of Parma; Parma Italy
| | - Daniele Del Rio
- Human Nutrition Unit; Department of Food & Drug; University of Parma; Parma Italy
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8
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Thorsheim K, Siegbahn A, Johnsson RE, Stålbrand H, Manner S, Widmalm G, Ellervik U. Chemistry of xylopyranosides. Carbohydr Res 2015; 418:65-88. [PMID: 26580709 DOI: 10.1016/j.carres.2015.10.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 10/09/2015] [Accepted: 10/10/2015] [Indexed: 12/22/2022]
Abstract
Xylose is one of the few monosaccharidic building blocks that are used by mammalian cells. In comparison with other monosaccharides, xylose is rather unusual and, so far, only found in two different mammalian structures, i.e. in the Notch receptor and as the linker between protein and glycosaminoglycan (GAG) chains in proteoglycans. Interestingly, simple soluble xylopyranosides can not only initiate the biosynthesis of soluble GAG chains but also function as inhibitors of important enzymes in the biosynthesis of proteoglycans. Furthermore, xylose is a major constituent of hemicellulosic xylans and thus one of the most abundant carbohydrates on Earth. Altogether, this has spurred a strong interest in xylose chemistry. The scope of this review is to describe synthesis of xylopyranosyl donors, as well as protective group chemistry, modifications, and conformational analysis of xylose.
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Affiliation(s)
- Karin Thorsheim
- Centre for Analysis and Synthesis, Centre for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Anna Siegbahn
- Centre for Analysis and Synthesis, Centre for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Richard E Johnsson
- Centre for Analysis and Synthesis, Centre for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Henrik Stålbrand
- Centre for Molecular Protein Science, Centre for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Sophie Manner
- Centre for Analysis and Synthesis, Centre for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Göran Widmalm
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Ulf Ellervik
- Centre for Analysis and Synthesis, Centre for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.
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9
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Siegbahn A, Thorsheim K, Ståhle J, Manner S, Hamark C, Persson A, Tykesson E, Mani K, Westergren-Thorsson G, Widmalm G, Ellervik U. Exploration of the active site of β4GalT7: modifications of the aglycon of aromatic xylosides. Org Biomol Chem 2015; 13:3351-62. [PMID: 25655827 DOI: 10.1039/c4ob02632b] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Proteoglycans (PGs) are macromolecules that consist of long linear polysaccharides, glycosaminoglycan (GAG) chains, covalently attached to a core protein by the carbohydrate xylose. The biosynthesis of GAG chains is initiated by xylosylation of the core protein followed by galactosylation by the galactosyltransferase β4GalT7. Some β-d-xylosides, such as 2-naphthyl β-d-xylopyranoside, can induce GAG synthesis by serving as acceptor substrates for β4GalT7 and by that also compete with the GAG synthesis on core proteins. Here we present structure-activity relationships for β4GalT7 and xylosides with modifications of the aromatic aglycon, using enzymatic assays, cell studies, and molecular docking simulations. The results show that the aglycons reside on the outside of the active site of the enzyme and that quite bulky aglycons are accepted. By separating the aromatic aglycon from the xylose moiety by linkers, a trend towards increased galactosylation with increased linker length is observed. The galactosylation is influenced by the identity and position of substituents in the aromatic framework, and generally, only xylosides with β-glycosidic linkages function as good substrates for β4GalT7. We also show that the galactosylation ability of a xyloside is increased by replacing the anomeric oxygen with sulfur, but decreased by replacing it with carbon. Finally, we propose that reaction kinetics of galactosylation by β4GalT7 is dependent on subtle differences in orientation of the xylose moiety.
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Affiliation(s)
- Anna Siegbahn
- Center for Analysis and Synthesis, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.
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10
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Brusa C, Muzard M, Rémond C, Plantier-Royon R. β-Xylopyranosides: synthesis and applications. RSC Adv 2015. [DOI: 10.1039/c5ra14023d] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In recent years, β-xylopyranosides have attracted interest due to the development of biomass-derived molecules. This review focuses on general routes for the preparation of β-xylopyranosides by chemical and enzymatic pathways and their main uses.
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Affiliation(s)
- Charlotte Brusa
- Université de Reims Champagne-Ardenne
- Institut de Chimie Moléculaire de Reims (ICMR)
- CNRS UMR 7312
- UFR Sciences Exactes et Naturelles
- F-51687 Reims Cedex 2
| | - Murielle Muzard
- Université de Reims Champagne-Ardenne
- Institut de Chimie Moléculaire de Reims (ICMR)
- CNRS UMR 7312
- UFR Sciences Exactes et Naturelles
- F-51687 Reims Cedex 2
| | - Caroline Rémond
- Université de Reims Champagne-Ardenne
- UMR 614
- Fractionnement des AgroRessources et Environnement
- France
- INRA
| | - Richard Plantier-Royon
- Université de Reims Champagne-Ardenne
- Institut de Chimie Moléculaire de Reims (ICMR)
- CNRS UMR 7312
- UFR Sciences Exactes et Naturelles
- F-51687 Reims Cedex 2
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11
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Siegbahn A, Manner S, Persson A, Tykesson E, Holmqvist K, Ochocinska A, Rönnols J, Sundin A, Mani K, Westergren-Thorsson G, Widmalm G, Ellervik U. Rules for priming and inhibition of glycosaminoglycan biosynthesis; probing the β4GalT7 active site. Chem Sci 2014. [DOI: 10.1039/c4sc01244e] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Xylose is the optimal substrate for β4GalT7, an essential enzyme in GAG biosynthesis, but analogs act as effective inhibitors.
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Affiliation(s)
- Anna Siegbahn
- Centre for Analysis and Synthesis
- Centre for Chemistry and Chemical Engineering
- Lund University
- SE-221 00 Lund, Sweden
| | - Sophie Manner
- Centre for Analysis and Synthesis
- Centre for Chemistry and Chemical Engineering
- Lund University
- SE-221 00 Lund, Sweden
| | - Andrea Persson
- Centre for Analysis and Synthesis
- Centre for Chemistry and Chemical Engineering
- Lund University
- SE-221 00 Lund, Sweden
- Department of Experimental Medical Science
| | - Emil Tykesson
- Department of Experimental Medical Science
- Lund University
- SE-221 00 Lund, Sweden
| | - Karin Holmqvist
- Centre for Analysis and Synthesis
- Centre for Chemistry and Chemical Engineering
- Lund University
- SE-221 00 Lund, Sweden
| | - Agata Ochocinska
- Centre for Analysis and Synthesis
- Centre for Chemistry and Chemical Engineering
- Lund University
- SE-221 00 Lund, Sweden
| | - Jerk Rönnols
- Department of Organic Chemistry
- Arrhenius Laboratory
- Stockholm University
- SE-106 91 Stockholm, Sweden
| | - Anders Sundin
- Centre for Analysis and Synthesis
- Centre for Chemistry and Chemical Engineering
- Lund University
- SE-221 00 Lund, Sweden
| | - Katrin Mani
- Department of Experimental Medical Science
- Lund University
- SE-221 00 Lund, Sweden
| | | | - Göran Widmalm
- Department of Organic Chemistry
- Arrhenius Laboratory
- Stockholm University
- SE-106 91 Stockholm, Sweden
| | - Ulf Ellervik
- Centre for Analysis and Synthesis
- Centre for Chemistry and Chemical Engineering
- Lund University
- SE-221 00 Lund, Sweden
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12
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Ishiwata A, Sakurai A, Nishimiya Y, Tsuda S, Ito Y. Synthetic study and structural analysis of the antifreeze agent xylomannan from Upis ceramboides. J Am Chem Soc 2011; 133:19524-35. [PMID: 22029271 DOI: 10.1021/ja208528c] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The novel antifreeze factor, xylomannan, first isolated from the freeze-tolerant Alaskan beetle Upis ceramboides , demonstrates a high degree of thermal hysteresis, comparable to that of the most active insect antifreeze proteins. Although the presence of a lipid component in this factor has not yet been verified, it has been proposed that the glycan backbone consists of a β-D-mannopyranosyl-(1→4)-β-D-xylopyranose-disaccharide-repeating structure according to MS and NMR analyses. In this contribution, we report the stereoselective synthesis of the tetrasaccharide β-D-mannopyranosyl-(1→4)-β-D-xylopyranosyl-(1→4)-β-D-mannopyranosyl-(1→4)-D-xylopyranoside, a structural component of xylomannan. Our synthesis features the use of 2-naphthylmethyl (NAP)-ether-mediated intramolecular aglycon delivery (IAD) as the key reaction in obtaining β-mannopyranoside stereoselectively. Various donors for NAP-IAD were tested to determine the most suitable for the purposes of this synthesis. Fragment coupling between a disaccharyl fluoride and a disaccharide acceptor obtained from a common β-D-mannopyranosyl-(1→4)-β-D-xylopyranoside derivative was successfully carried out to afford the desired tetrasaccharide in the presence of Cp(2)HfCl(2)-AgClO(4). Structural analysis of the resulting synthetic tetrasaccharide using NMR techniques and molecular modeling was performed in order to demonstrate the presence of the proposed xylomannan linkages in this molecule.
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Affiliation(s)
- Akihiro Ishiwata
- RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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13
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Siegbahn A, Aili U, Ochocinska A, Olofsson M, Rönnols J, Mani K, Widmalm G, Ellervik U. Synthesis, conformation and biology of naphthoxylosides. Bioorg Med Chem 2011; 19:4114-26. [DOI: 10.1016/j.bmc.2011.05.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 04/29/2011] [Accepted: 05/04/2011] [Indexed: 10/18/2022]
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14
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Martel F, Estrine B, Plantier-Royon R, Hoffmann N, Portella C. Development of Agriculture Left-Overs: Fine Organic Chemicals from Wheat Hemicellulose-Derived Pentoses. Top Curr Chem (Cham) 2010; 294:79-115. [DOI: 10.1007/128_2010_54] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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15
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Jacobsson M, Oxgaard J, Abrahamsson CO, Norrby PO, Goddard WA, Ellervik U. Acid-catalyzed nucleophilic aromatic substitution: experimental and theoretical exploration of a multistep mechanism. Chemistry 2008; 14:3954-60. [PMID: 18351696 DOI: 10.1002/chem.200701590] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The mechanism for the acid-mediated substitution of a phenolic hydroxyl group with a sulfur nucleophile has been investigated by a combination of experimental and theoretical methods. We conclude that the mechanism is distinctively different in nonpolar solvents (i.e., toluene) compared with polar solvents. The cationic mechanism, proposed for the reaction in polar solvents, is not feasible and the reaction instead proceeds through a multistep mechanism in which the acid (pTsOH) mediates the proton shuffling. From DFT calculations, we found a rate-determining transition state with protonation of the hydroxyl group to generate free water and a tight ion pair between a cationic protonated naphthalene species and a tosylate anion. Kinetic experiments support this mechanism and show that, at moderate concentrations, the reaction is first order with respect to 2-naphthol, n-propanethiol, and p-toluenesulfonic acid (pTsOH). Experimentally determined activation parameters are similar to the calculated values (Delta H exp not equal =105+/-9, Delta H calcd not equal =118 kJ mol(-1); Delta G exp not equal =112+/-18, Delta G calcd not equal =142 kJ mol(-1)).
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Affiliation(s)
- Mårten Jacobsson
- Organic Chemistry, Lund University, PO Box 124, 22100 Lund, Sweden
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