1
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Xiao Q, Fang S, Ao J, Zhao X, Huang C, Liu Y, Nie Y, Ishiwata A, Tanaka K, Deng W, Ding F. B(C 6F 5) 3-Catalyzed Stereoselective 1,2- cis Arabinofuranosylation with a Conformationally Constrained Donor. ACS OMEGA 2024; 9:11969-11975. [PMID: 38497025 PMCID: PMC10938590 DOI: 10.1021/acsomega.3c09761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/19/2024] [Accepted: 02/26/2024] [Indexed: 03/19/2024]
Abstract
Compared with stereoselective glycosylation methods mainly addressed on the preparation of pyranose glycosides, the furanosylation has been more limited, especially for the 1,2-cis arabinofuranosylation. Herein, we report a novel stereoselective 1,2-cis-arabinofuranosylation strategy using a conformationally restricted 3,5-O-xylylene-protected arabinofuranosyl donor on activation with B(C6F5)3 for desired targets in moderate to excellent yields and β-stereoselectivity. The effectiveness of the 1,2-cis-arabinofuranosylation strategy was demonstrated successfully with various acceptors, including carbohydrate alcohols.
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Affiliation(s)
- Qian Xiao
- School
of Pharmaceutical Sciences (Shenzhen), Shenzhen
Campus of Sun Yat-sen University, Shenzhen 518107, China
| | - Sixian Fang
- School
of Pharmaceutical Sciences (Shenzhen), Shenzhen
Campus of Sun Yat-sen University, Shenzhen 518107, China
| | - Jiaming Ao
- School
of Pharmaceutical Sciences (Shenzhen), Shenzhen
Campus of Sun Yat-sen University, Shenzhen 518107, China
| | - Xiaoya Zhao
- School
of Pharmaceutical Sciences (Shenzhen), Shenzhen
Campus of Sun Yat-sen University, Shenzhen 518107, China
| | - Cai Huang
- School
of Pharmaceutical Sciences (Shenzhen), Shenzhen
Campus of Sun Yat-sen University, Shenzhen 518107, China
| | - Yuhua Liu
- School
of Physics and Electronic Engineering, Guangzhou
University, Guangzhou 510006, China
| | - Yichu Nie
- Translational
Medicine Research Institute, First People’s
Hospital of Foshan, Foshan 528000, China
| | - Akihiro Ishiwata
- RIKEN
Cluster for Pioneering Research, Wako, Saitama 3510198, Japan
| | - Katsunori Tanaka
- RIKEN
Cluster for Pioneering Research, Wako, Saitama 3510198, Japan
- Department
of Chemical Science and Engineering, Tokyo
Institute of Technology, Tokyo 152-8552, Japan
| | - Wenbin Deng
- School
of Pharmaceutical Sciences (Shenzhen), Shenzhen
Campus of Sun Yat-sen University, Shenzhen 518107, China
| | - Feiqing Ding
- School
of Pharmaceutical Sciences (Shenzhen), Shenzhen
Campus of Sun Yat-sen University, Shenzhen 518107, China
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2
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Zhao J, Esque J, André I, O'Donohue MJ, Fauré R. Synthesis of α-l-Araf and β-d-Galf series furanobiosides using mutants of a GH51 α-l-arabinofuranosidase. Bioorg Chem 2021; 116:105245. [PMID: 34482168 DOI: 10.1016/j.bioorg.2021.105245] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/29/2021] [Accepted: 08/02/2021] [Indexed: 10/20/2022]
Abstract
The GH-51 α-l-arabinofuranosidase from Thermobacillus xylanilyticus (TxAbf) possesses versatile catalytic properties, displaying not only the ability to hydrolyze glycosidic linkages but also to synthesize furanobiosides in α-l-Araf and β-d-Galf series. Herein, mutants are investigated to evaluate their ability to perform self-condensation, assessing both yield improvements and changes in regioselectivity. Overall yields of oligo-α-l-arabino- and oligo-β-d-galactofuranosides were increased up to 4.8-fold compared to the wild-type enzyme. In depth characterization revealed that the mutants exhibit increased transfer rates and thus a hydrolysis/self-condensation ratio in favor of synthesis. The consequence of the substitution N216W is the creation of an additional binding subsite that provides the basis for an alternative acceptor substrate binding mode. As a result, mutants bearing N216W synthesize not only (1,2)-linked furanobiosides, but also (1,3)- and even (1,5)-linked furanobiosides. Since the self-condensation is under kinetic control, the yield of homo-disaccharides was maximized using higher substrate concentrations. In this way, the mutant R69H-N216W produced oligo-β-d-galactofuranosides in > 70% yield. Overall, this study further demonstrates the potential usefulness of TxAbf mutants for glycosynthesis and shows how these might be used to synthesize biologically-relevant glycoconjugates.
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Affiliation(s)
- Jiao Zhao
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - Jérémy Esque
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - Isabelle André
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | | | - Régis Fauré
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France.
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3
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Fittolani G, Tyrikos-Ergas T, Vargová D, Chaube MA, Delbianco M. Progress and challenges in the synthesis of sequence controlled polysaccharides. Beilstein J Org Chem 2021; 17:1981-2025. [PMID: 34386106 PMCID: PMC8353590 DOI: 10.3762/bjoc.17.129] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 07/22/2021] [Indexed: 01/15/2023] Open
Abstract
The sequence, length and substitution of a polysaccharide influence its physical and biological properties. Thus, sequence controlled polysaccharides are important targets to establish structure-properties correlations. Polymerization techniques and enzymatic methods have been optimized to obtain samples with well-defined substitution patterns and narrow molecular weight distribution. Chemical synthesis has granted access to polysaccharides with full control over the length. Here, we review the progress towards the synthesis of well-defined polysaccharides. For each class of polysaccharides, we discuss the available synthetic approaches and their current limitations.
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Affiliation(s)
- Giulio Fittolani
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
- Department of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany
| | - Theodore Tyrikos-Ergas
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
- Department of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany
| | - Denisa Vargová
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Manishkumar A Chaube
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Martina Delbianco
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
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4
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Seničar M, Lafite P, Eliseeva SV, Petoud S, Landemarre L, Daniellou R. Galactofuranose-Related Enzymes: Challenges and Hopes. Int J Mol Sci 2020; 21:ijms21103465. [PMID: 32423053 PMCID: PMC7278926 DOI: 10.3390/ijms21103465] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 05/08/2020] [Accepted: 05/11/2020] [Indexed: 12/22/2022] Open
Abstract
Galactofuranose is a rare form of the well-known galactose sugar, and its occurrence in numerous pathogenic micro-organisms makes the enzymes responsible for its biosynthesis interesting targets. Herein, we review the role of these carbohydrate-related proteins with a special emphasis on the galactofuranosidases we recently characterized as an efficient recombinant biocatalyst.
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Affiliation(s)
- Mateja Seničar
- Institut de Chimie Organique et Analytique, CNRS UMR 7311, Université d’Orléans, Rue de Chartres, BP 6759, CEDEX 2, 45067 Orléans, France; (M.S.); (P.L.)
- Centre de Biophysique Moléculaire, CNRS UPR 4301, Rue Charles Sadron CS 8005, 45071 Orléans, France; (S.V.E.); (S.P.)
| | - Pierre Lafite
- Institut de Chimie Organique et Analytique, CNRS UMR 7311, Université d’Orléans, Rue de Chartres, BP 6759, CEDEX 2, 45067 Orléans, France; (M.S.); (P.L.)
| | - Svetlana V. Eliseeva
- Centre de Biophysique Moléculaire, CNRS UPR 4301, Rue Charles Sadron CS 8005, 45071 Orléans, France; (S.V.E.); (S.P.)
| | - Stéphane Petoud
- Centre de Biophysique Moléculaire, CNRS UPR 4301, Rue Charles Sadron CS 8005, 45071 Orléans, France; (S.V.E.); (S.P.)
| | | | - Richard Daniellou
- Institut de Chimie Organique et Analytique, CNRS UMR 7311, Université d’Orléans, Rue de Chartres, BP 6759, CEDEX 2, 45067 Orléans, France; (M.S.); (P.L.)
- Correspondence: ; Tel.: +33-238-494-978
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5
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Xu C, Loh CCJ. An ultra-low thiourea catalyzed strain-release glycosylation and a multicatalytic diversification strategy. Nat Commun 2018; 9:4057. [PMID: 30282986 PMCID: PMC6170412 DOI: 10.1038/s41467-018-06329-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 08/30/2018] [Indexed: 11/09/2022] Open
Abstract
The utility of thiourea catalysis in selective glycosylation strategies has gained significant momentum lately due to its versatility in hydrogen bonding or anionic recognition activation modes. The use of these non-covalent interactions constitute a powerful means to construct glycosidic linkages as it mimics physiologically occurring glycosyltransferases. However, glycosyl donor activation through the currently employed catalysts is moderate such that, in general, catalyst loadings are rather high in these transformations. In addition, thiourea catalysis has not been well explored for the synthesis of furanosides. Herein, we demonstrate an ultra-low loadings stereoselective and stereospecific thiourea catalyzed strain-release furanosylation and pyranosylation strategy. Our ultra-low organocatalyzed furanosylation enables a multicatalytic strategy, which opens up a unique avenue towards rapid diversification of synthetic glycosides. In-situ NMR monitoring unravel insights into unknown reaction intermediates and initial rate kinetic studies reveal a plausible synergistic hydrogen bonding/Brønsted acid activation mode. Non-covalent glycosyl donor activation often requires high organocatalyst loadings. Here, the authors demonstrate that strain-release glycosylations can take place at very low thiourea catalyst loadings. In addition, the authors developed a one-pot multicatalytic strategy that can diversify glycosides rapidly.
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Affiliation(s)
- Chunfa Xu
- Fakultät für Chemie und Chemische Biologie, Technische Universität Dortmund,, Otto-Hahn-Straße 4a, 44227, Dortmund, Germany.,Abteilung Chemische Biologie, Max Planck Institut für Molekulare Physiologie, Otto-Hahn-Straße 11, 44227, Dortmund, Germany
| | - Charles C J Loh
- Fakultät für Chemie und Chemische Biologie, Technische Universität Dortmund,, Otto-Hahn-Straße 4a, 44227, Dortmund, Germany. .,Abteilung Chemische Biologie, Max Planck Institut für Molekulare Physiologie, Otto-Hahn-Straße 11, 44227, Dortmund, Germany.
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6
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Walczak D, Nowacki A, Trzybiński D, Samaszko-Fiertek J, Myszka H, Sikorski A, Liberek B. Conformational studies of N-(α-d-glucofuranurono-6,3-lactone)- and N-(methyl β-d-glucopyranuronate)-p-nitroanilines. Carbohydr Res 2017; 446-447:85-92. [PMID: 28554013 DOI: 10.1016/j.carres.2017.05.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 04/28/2017] [Accepted: 05/13/2017] [Indexed: 10/19/2022]
Abstract
N-(α-d-Glucofuranurono-6,3-lactone)-p-nitroaniline and N-(methyl β-d-glucopyranuronate)-p-nitroaniline were obtained as crystalline solids. The single-crystal X-ray diffraction, NMR data and DFT calculations for N-(α-d-glucofuranurono-6,3-lactone)-p-nitroaniline indicate that this N-furanoside adopts a 3T2/3E-like conformation in the crystal lattice, solution and gas phase. Thus, the structure of recorded for N-furanoside 1H NMR spectrum is indicative of the 3T2/3E region of the pseudorotational itinerary for furanose derivatives with α-d-gluco, β-L-ido and α-d-xylo configurations. Moreover, it is concluded that the 1T2/E2/3T2/3E region of the pseudorotational itinerary for furanose derivatives with d-gluco, L-ido and d-xylo configurations should be characterised by the lack of coupling between H2 and H3 protons, irrespective of the anomeric configuration. Such a lack of vicinal coupling is characteristic for some of the trans-oriented furanose ring protons. The single-crystal X-ray diffraction and NMR data for N-(methyl β-d-glucopyranuronate)-p-nitroaniline indicate that this N-glucuronide adopts the 4C1 conformation, both in the crystal lattice and solution. The occurrence of anomeric effects in the presented N-glycosides is discussed. The crystal structure analysis of both N-glycosides gives evidence that the amine group in p-nitroaniline is planar due to the nitrogen sp2 hybridisation.
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Affiliation(s)
- Dominik Walczak
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Andrzej Nowacki
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Damian Trzybiński
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland; Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
| | | | - Henryk Myszka
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Artur Sikorski
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Beata Liberek
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland.
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7
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Lee BY, Oh JW, Baek JY, Jeon HB, Kim KS. Phthalic Anhydride-Mediated Direct Glycosylation of Anomeric Hydroxy Arabinofuranose: Synthesis of Repeating Oligoarabinofuranoside and Tetradecasaccharide Arabinan Motif of Mycobacterial Cell Wall. J Org Chem 2016; 81:11372-11383. [DOI: 10.1021/acs.joc.6b01723] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Bo-Young Lee
- Center
for Bioactive Molecular Hybrids and Department of Chemistry, Yonsei University, Seoul 120-749, Korea
| | - Jung Woo Oh
- Center
for Bioactive Molecular Hybrids and Department of Chemistry, Yonsei University, Seoul 120-749, Korea
| | - Ju Yuel Baek
- Center
for Bioactive Molecular Hybrids and Department of Chemistry, Yonsei University, Seoul 120-749, Korea
| | - Heung Bae Jeon
- Department
of Chemistry, Kwangwoon University, Seoul 139-701, Korea
| | - Kwan Soo Kim
- Center
for Bioactive Molecular Hybrids and Department of Chemistry, Yonsei University, Seoul 120-749, Korea
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8
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Winton VJ, Aldrich C, Kiessling LL. Carboxylate Surrogates Enhance the Antimycobacterial Activity of UDP-Galactopyranose Mutase Probes. ACS Infect Dis 2016; 2:538-43. [PMID: 27626294 DOI: 10.1021/acsinfecdis.6b00021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Uridine diphosphate galactopyranose mutase (UGM also known as Glf) is a biosynthetic enzyme required for construction of the galactan, an essential mycobacterial cell envelope polysaccharide. Our group previously identified two distinct classes of UGM inhibitors; each possesses a carboxylate moiety that is crucial for potency yet likely detrimental for cell permeability. To enhance the antimycobacterial potency, we sought to replace the carboxylate with a functional group mimic-an N-acylsulfonamide group. We therefore synthesized a series of N-acylsulfonamide analogs and tested their ability to inhibit UGM. For each inhibitor scaffold tested, the N-acylsulfonamide group functions as an effective carboxylate surrogate. Although the carboxylates and their surrogates show similar activity against UGM in a test tube, several N-acylsulfonamide derivatives more effectively block the growth of Mycobacterium smegmatis. These data suggest that the replacement of a carboxylate with an N-acylsulfonamide group could serve as a general strategy to augment antimycobacterial activity.
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Affiliation(s)
- Valerie J. Winton
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Claudia Aldrich
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Laura L. Kiessling
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
- Department
of Biochemistry, University of Wisconsin—Madison, 433 Babcock Drive, Madison, Wisconsin 53706-1544, United States
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9
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Arab-Jaziri F, Bissaro B, Tellier C, Dion M, Fauré R, O’Donohue MJ. Enhancing the chemoenzymatic synthesis of arabinosylated xylo-oligosaccharides by GH51 α-l-arabinofuranosidase. Carbohydr Res 2015; 401:64-72. [DOI: 10.1016/j.carres.2014.10.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 10/28/2014] [Accepted: 10/30/2014] [Indexed: 02/04/2023]
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10
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Marino C, Baldoni L. Synthesis of D-galactofuranose-containing molecules: design of galactofuranosyl acceptors. Chembiochem 2014; 15:188-204. [PMID: 24420700 DOI: 10.1002/cbic.201300638] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Indexed: 11/11/2022]
Abstract
D-Galactofuranose (D-Galf) is present in glycoconjugates of several pathogenic microorganisms but is absent in mammals, so it is a good target for the development of chemotherapeutic agents for the treatment of microbial infections. This fact has increased interest in the synthesis of D-Galf-containing molecules for corresponding glycobiological studies. The synthesis of oligosaccharides, glycoconjugates, and mimetics of D-Galf requires specific methods for the preparation of galactose derivatives in the furanosic configuration, the synthesis of appropriate acceptors, and efficient glycosylation methods for the construction of α- and β-D-Galf linkages. This review summarizes the different strategies developed for the preparation of partially protected derivatives of D-Galf, suitable as acceptors for the construction of (1→2), (1→3), (1→5), and (1→6) link- ages, and describes recent applications.
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Affiliation(s)
- Carla Marino
- CIHIDECAR-CONICET-UBA, Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón II, Ciudad Universitaria, 1428 Buenos Aires (Argentina).
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11
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Islam SM, Roy PN. Performance of the SCC-DFTB Model for Description of Five-Membered Ring Carbohydrate Conformations: Comparison to Force Fields, High-Level Electronic Structure Methods, and Experiment. J Chem Theory Comput 2012; 8:2412-23. [DOI: 10.1021/ct200789w] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Shahidul M. Islam
- Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Pierre-Nicholas Roy
- Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
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12
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Novel glycolipid TLR2 ligands of the type Pam2Cys-α-Gal: Synthesis and biological properties. Eur J Med Chem 2012; 51:174-83. [DOI: 10.1016/j.ejmech.2012.02.039] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 02/03/2012] [Accepted: 02/18/2012] [Indexed: 01/29/2023]
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13
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Repetto E, Manzano VE, Uhrig ML, Varela O. Synthesis of Branched Dithiotrisaccharides via Ring-Opening Reaction of Sugar Thiiranes. J Org Chem 2011; 77:253-65. [DOI: 10.1021/jo2018685] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Evangelina Repetto
- CIHIDECAR-CONICET, Departamento de Química Orgánica,
Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | - Verónica E. Manzano
- CIHIDECAR-CONICET, Departamento de Química Orgánica,
Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | - María Laura Uhrig
- CIHIDECAR-CONICET, Departamento de Química Orgánica,
Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | - Oscar Varela
- CIHIDECAR-CONICET, Departamento de Química Orgánica,
Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
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14
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Tilve MJ, Gallo-Rodriguez C. Glycosylation studies on conformationally restricted 3,5-O-(di-tert-butylsilylene)-D-galactofuranosyl trichloroacetimidate donors for 1,2-cis α-D-galactofuranosylation. Carbohydr Res 2011; 346:2838-48. [PMID: 22050997 DOI: 10.1016/j.carres.2011.10.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 10/03/2011] [Accepted: 10/04/2011] [Indexed: 10/16/2022]
Abstract
Conformationally restricted 3,5-O-di-tert-butylsilylene-D-galactofuranosyl trichloroacetimidate donors were synthesized from allyl α-D-galactofuranoside for the construction of 1,2-cis α-D-galactofuranosyl linkages. Glycosylation reactions were performed with several acceptors, including D-galactono-1,4-lactone, D-rhamnopyranosyl, and D-mannopyranosyl derivatives. The influence of the temperature and the reaction solvents was evaluated, as well as the 6-O-substitution pattern of the donor. The higher α-selectivities were obtained at -78 °C in diethyl ether as solvent. 6-O-Acetyl substitution on constrained donor increased the α-selectivity compared to the 6-O-benzyl substitution. Almost no selectivities were observed in the non-participating solvent CH(2)Cl(2). In contrast, ethereal solvents enhanced the α-selectivity suggesting a participating effect in the reaction intermediate.
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Affiliation(s)
- Mariano J Tilve
- CIHIDECAR, Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón II, 1428 Buenos Aires, Argentina
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15
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Influence of the solvent in low temperature glycosylations with O-(2,3,5,6-tetra-O-benzyl-β-D-galactofuranosyl) trichloroacetimidate for 1,2-cis α-D-galactofuranosylation. Carbohydr Res 2011; 346:1495-502. [PMID: 21645887 DOI: 10.1016/j.carres.2011.04.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 03/31/2011] [Accepted: 04/04/2011] [Indexed: 11/22/2022]
Abstract
Glycosylation studies for the construction of 1,2-cis α-linkages with O-(2,3,5,6-tetra-O-benzyl-β-D-galactofuranosyl) trichloroacetimidate (1) and several acceptors, including D-mannosyl and l-rhamnosyl derivatives were performed. The reactions were conducted at low temperatures using CH(2)Cl(2), Et(2)O, and acetonitrile as solvents. A non-participating solvent such as CH(2)Cl(2) at -78°C, favored the α-D-configuration. In contrast, acetonitrile strongly favored the β-D-configuration, whereas no selectivities were observed with Et(2)O. The use of thiophene as an additive did not enhance the α-D-selectivity as in the pyranose counterpart. Although selectivities strongly depended on the acceptor, trichloroacetimidate 1 constitutes a valuable donor for the synthesis of α-D-Galf-(1→2)-l-Rha and α-D-Galf-(1→6)-D-Man. As these motifs are present in pathogenic microorganisms, these procedures described here are useful for the straightforward synthesis of natural oligosaccharides.
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16
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Ishiwata A, Ito Y. Synthesis of docosasaccharide arabinan motif of mycobacterial cell wall. J Am Chem Soc 2011; 133:2275-91. [PMID: 21287985 DOI: 10.1021/ja109932t] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Mycobacterial arabinan is a common constituent of both arabinogalactan (AG) and lipoarabinomannan (LAM). In this study, synthesis of β-Araf containing common arabinan docosasaccharide motif (22 Araf monomer units) of mycobacterial cell wall was achieved. Our synthetic strategy toward arabinan involves (1) the stereoselective β-arabinofuranosylation using both 3,5-O-TIPDS-protected and NAP-protected arabinofuranosyl donors for straightforward intermolecular glycosylation and intramolecular aglycon delivery (IAD), respectively, and (2) the convergent fragment coupling with branched fragments at the linear sequence using thioglycoside donor obtained from the corresponding acetonide at the reducing terminal of each fragment through a three-step procedure. Because the acetonide at the reducing terminal of all fragments would be converted to thioglycoside as the glycosyl donor, and mainly Bn ether protections were used, our strategy will be readily applicable to the synthesis of more complex arabinan, arabinogalactan, and arabinomycolate derived from mycobacterial CWS.
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Affiliation(s)
- Akihiro Ishiwata
- RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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Gandolfi-Donadío L, Santos M, de Lederkremer RM, Gallo-Rodriguez C. Synthesis of arabinofuranose branched galactofuran tetrasaccharides, constituents of mycobacterial arabinogalactan. Org Biomol Chem 2011; 9:2085-97. [DOI: 10.1039/c0ob00989j] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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18
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Szczepina MG, Zheng RB, Completo GC, Lowary TL, Pinto BM. STD-NMR studies of two acceptor substrates of GlfT2, a galactofuranosyltransferase from Mycobacterium tuberculosis: epitope mapping studies. Bioorg Med Chem 2010; 18:5123-8. [PMID: 20591680 DOI: 10.1016/j.bmc.2010.05.069] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2010] [Revised: 05/23/2010] [Accepted: 05/25/2010] [Indexed: 10/19/2022]
Abstract
The major structural component of the mycobacterial cell wall, the mycolyl-arabinogalactan-peptidoglycan complex, possesses a galactan core composed of approximately 30 galactofuranosyl (Galf) resides attached via alternating beta-(1-->6) and beta-(1-->5) linkages. Recent studies have shown that the entire galactan is synthesized by two bifunctional galactofuranosyltransferases, GlfT1 and GlfT2. We report here saturation transfer difference (STD) NMR studies GlfT2 using two trisaccharide acceptor substrates, beta-D-Galf-(1-->6)-beta-D-Galf-(1-->5)-beta-D-Galf-O(CH2)7CH3 (2) and beta-D-Galf-(1-->5)-beta-D-Galf-(1-->6)-beta-D-Galf-O(CH2)7CH3 (3), as well as the donor substrate for the enzyme, UDP-Galf. Epitope mapping demonstrated a greater enhancement toward the 'reducing' ends of both trisaccharides, and that UDP-galactofuranose (UDP-Galf) made more intimate contacts through its nucleotide moiety. This observation is consistent with the greater flexibility required within the active site of the reaction between the growing polymer acceptor and the UDP-Galf donor. The addition of UDP-Galf to either 2 or 3 in the presence of GlfT2 generated a tetrasaccharide product, indicating that the enzyme was catalytically active.
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Affiliation(s)
- Monica G Szczepina
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
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Dureau R, Robert-Gangneux F, Gangneux JP, Nugier-Chauvin C, Legentil L, Daniellou R, Ferrières V. Synthetic UDP-furanoses inhibit the growth of the parasite Leishmania. Carbohydr Res 2010; 345:1299-305. [PMID: 20303072 DOI: 10.1016/j.carres.2010.02.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Revised: 02/11/2010] [Accepted: 02/20/2010] [Indexed: 11/28/2022]
Abstract
The chemical synthesis of UDP-6-NHAc-6-deoxy-Galf was performed and it led to the isolation of both pure anomers. They were then evaluated together with the previously prepared UDP-furanoses for their anti-parasitic properties against Leishmania donovani promastigotes, one of the agents responsible for visceral leishmaniasis. Amongst them, the unnatural 1,2-trans UDP-6-NHAc-Galf demonstrated a high potency in inhibiting the growth of the parasite.
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Affiliation(s)
- Rémy Dureau
- Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, Avenue du Général Leclerc, CS 50837, 35708 Rennes Cedex 7, France
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20
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Chlubnová I, Filipp D, Spiwok V, Dvořáková H, Daniellou R, Nugier-Chauvin C, Králová B, Ferrières V. Enzymatic synthesis of oligo-d-galactofuranosides and l-arabinofuranosides: from molecular dynamics to immunological assays. Org Biomol Chem 2010; 8:2092-102. [DOI: 10.1039/b926988f] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Richards MR, Lowary TL. Chemistry and biology of galactofuranose-containing polysaccharides. Chembiochem 2009; 10:1920-38. [PMID: 19591187 DOI: 10.1002/cbic.200900208] [Citation(s) in RCA: 170] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The thermodynamically less stable form of galactose-galactofuranose (Galf)-is essential for the viability of several pathogenic species of bacteria and protozoa but absent in this form in mammals, so the biochemical pathways by which Galf-containing glycans are assembled and catabolysed are attractive sites for drug action. This potential has led to increasing interest in the synthesis of molecules containing Galf residues, their subsequent use in studies directed towards understanding the enzymes that process these residues and the identification of potential inhibitors of these pathways. Major achievements of the past several years have included an in-depth understanding of the mechanism of UDP-galactopyranose mutase (UGM), the enzyme that produces UDP-Galf, which is the donor species for galactofuranosyltransferases. A number of methods for the synthesis of galactofuranosides have also been developed, and practitioners in the field now have many options for the initiation of a synthesis of glycoconjugates containing either alpha- or beta-Galf residues. UDP-Galf has also been prepared by a number of approaches, and it appears that a chemoenzymatic approach is currently the most viable method for producing multi-milligram amounts of this important intermediate. Recent advances both in the understanding of the mechanism of UGM and in the synthesis of galactofuranose and its derivatives are highlighted in this review.
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Affiliation(s)
- Michele R Richards
- Alberta Ingenuity Centre for Carbohydrate Science and Department of Chemistry, University of Alberta, Gunning-Lemieux Chemistry Centre, Edmonton, AB T6G 2G2 (Canada)
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22
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Szczepina MG, Zheng RB, Completo GC, Lowary TL, Pinto BM. STD-NMR studies suggest that two acceptor substrates for GlfT2, a bifunctional galactofuranosyltransferase required for the biosynthesis of Mycobacterium tuberculosis arabinogalactan, compete for the same binding site. Chembiochem 2009; 10:2052-9. [PMID: 19575371 DOI: 10.1002/cbic.200900202] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The mycobacterial cell wall is a complex architecture, which has, as its major structural component, a lipidated polysaccharide covalently bound to peptidoglycan. This structure, termed the mycolyl-arabinogalactan-peptidoglycan complex, possesses a core galactan moiety composed of approximately 30 galactofuranosyl (Galf) resides attached via alternating beta-(1-->6) and beta-(1-->5) linkages. Recent studies have shown that the entire galactan is synthesized by the action of only two bifunctional galactofuranosyltransferases, GlfT1 and GlfT2. We report here saturation-transfer difference (STD) NMR spectroscopy studies with GlfT2 using two trisaccharide acceptor substrates, beta-D-Galf-(1-->6)-beta-D-Galf-(1-->5)-beta-D-Galf-O(CH(2))(7)CH(3) (2) and beta-D-Galf-(1-->5)-beta-D-Galf-(1-->6)-beta-D-Galf-O(CH(2))(7)CH(3) (3), as well as the donor substrate for the enzyme, UDP-Galf. Competition STD-NMR titration experiments and saturation transfer double difference (STDD) experiments with 2 and 3 were undertaken to explore the bifunctionality of this enzyme, in particular to answer whether one or two active sites are responsible for the formation of both beta-(1-->5)- and beta-(1-->6)-Galf linkages. It was demonstrated that 2 and 3 bind competitively at the same site; this suggests that GlfT2 has one active site pocket capable of catalyzing both beta-(1-->5) and beta-(1-->6) galactofuranosyl transfer reactions. The addition of UDP-Galf to GlfT2 in the presence of either 2 or 3 generated a tetrasaccharide product; this indicates that the enzyme was catalytically active under the conditions at which the STD-NMR experiments were carried out.
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Affiliation(s)
- Monica G Szczepina
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia (Canada)
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23
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Glycosyl iodides. History and recent advances. Carbohydr Res 2009; 344:1110-22. [PMID: 19410241 DOI: 10.1016/j.carres.2009.02.032] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Revised: 02/17/2009] [Accepted: 02/23/2009] [Indexed: 11/21/2022]
Abstract
The use of glycosyl iodides as an effective method for the preparation of glycosides has had a recent resurgence in carbohydrate chemistry, despite its early roots in which these species were believed to be of limited use. Renewed interest in these species as glycosylating agents has been spurred by their demonstrated utility in the stereoselective preparation of O-glycosides, and other glycosylic compounds. This review provides a brief historical account followed by an examination of the use of glycosyl iodides in the synthesis of oligosaccharides and other glycomimetics, including C-glycosylic compounds, glycosyl azides and N-glycosides.
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Novel Galf-disaccharide mimics: synthesis by way of 1,3-dipolar cycloaddition reactions in water. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.tetasy.2008.08.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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25
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Peltier P, Euzen R, Daniellou R, Nugier-Chauvin C, Ferrières V. Recent knowledge and innovations related to hexofuranosides: structure, synthesis and applications. Carbohydr Res 2008; 343:1897-923. [DOI: 10.1016/j.carres.2008.02.010] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2007] [Revised: 02/08/2008] [Accepted: 02/12/2008] [Indexed: 10/22/2022]
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26
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Ruff Y, Lehn JM. Glycodynamers: Dynamic analogs of arabinofuranoside oligosaccharides. Biopolymers 2008; 89:486-96. [DOI: 10.1002/bip.20885] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Repetto E, Marino C, Uhrig ML, Varela O. Two Straightforward Strategies for the Synthesis of Thiodisaccharides with a Furanose Unit as the Nonreducing End. European J Org Chem 2008. [DOI: 10.1002/ejoc.200700874] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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28
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Seo M, Castillo N, Ganzynkowicz R, Daniels CR, Woods RJ, Lowary TL, Roy PN. Approach for the Simulation and Modeling of Flexible Rings: Application to the α-D-Arabinofuranoside Ring, a Key Constituent of Polysaccharides from Mycobacterium tuberculosis.. J Chem Theory Comput 2008; 4:184-191. [PMID: 25339852 PMCID: PMC4203666 DOI: 10.1021/ct700284r] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A number of lower organisms (bacteria, fungi, and parasites) produce glycoconjugates that contain furanose rings. Of particular interest to our group are cell wall polysaccharides from mycobacteria, including the human pathogen, Mycobacterium tuberculosis, which contain a large number of arabinofuranose resides. As part of a larger project on the conformational analysis of these molecules, we report here molecular dynamics simulations on methyl α-D-arabinofuranoside (1) using the AMBER force field and the GLYCAM carbohydrate parameter set. We initially studied the ability of this method to predict rotamer populations about the hydroxymethyl group (C4-C5) bond. Importantly, we show that simulation times of up to 200 ns are required in order to obtain convergence of the rotamer populations for this ring system. We also propose a new charge derivation approach that accounts for the flexibility of the furanoside ring by taking an average of the charges from a large number of conformers across the psuedorotational itinerary. The approach yields rotamer populations that are in good agreement with available NMR data and, in addition, provides insight into the nature of the puckering angle and amplitude in 1.
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Bohn ML, Colombo MI, Pisano PL, Stortz CA, Rúveda EA. Differential O-3/O-4 regioselectivity in the glycosylation of α and β anomers of 6-O-substituted N-dimethylmaleoyl-protected d-glucosamine acceptors. Carbohydr Res 2007; 342:2522-36. [PMID: 17880931 DOI: 10.1016/j.carres.2007.08.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Revised: 08/15/2007] [Accepted: 08/16/2007] [Indexed: 11/21/2022]
Abstract
An assessment of the relative O-3/O-4 reactivities of both methyl alpha- and beta-d-glycosides of N-dimethylmaleoyl (DMM) d-glucosamine acceptors protected at O-6 with benzoyl (Bz), benzyl (Bn), and tert-butyldiphenylsilyl (TBDPS) groups is presented using per-O-benzoylated beta-d-galactofuranosyl and per-O-acetylated alpha-d-galactopyranosyl trichloroacetimidates as glycosyl donors. Using the former donor, the alpha anomer of the 6-O-benzoylated compound gave exclusive substitution at O-3, whereas the other two compounds with alpha-configuration kept this site as preferential. The beta anomer of the 6-O-benzoylated compound gave the same amounts of reaction products on O-3 and O-4, whereas the other beta analogs carried a more reactive O-4. The same reactions were carried out using as donor the less-reactive per-O-acetylated alpha-d-galactopyranosyl trichloroacetimidate. Although the same trend was found to occur, the O-4 was always relatively more reactive with the pyranosyl donor than with the furanosyl donor, when keeping the remaining factors constant. Furthermore, the beta anomers of the acceptor gave almost exclusive substitution at O-4. These observations confirm and extend the utility of these 'matching' donor and acceptor reactivities.
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Affiliation(s)
- María L Bohn
- Instituto de Química Orgánica y de Síntesis (CONICET-UNR), Facultad de Ciencias Bioquímicas y Farmacéuticas, Suipacha 531, 2000 Rosario, Argentina
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Caravano A, Dohi H, Sinaÿ P, Vincent SP. A new methodology for the synthesis of fluorinated exo-glycals and their time-dependent inhibition of UDP-galactopyranose mutase. Chemistry 2007; 12:3114-23. [PMID: 16429471 DOI: 10.1002/chem.200500991] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Fluorinated carbohydrates constitute a very important class of mechanistic probes for glycosyl-processing enzymes. In this study, we describe the first synthesis of fluorinated and phosphonylated exo-glycals and their corresponding nucleotide sugars in the galactofuranose series. The synthetic protocol that we have developed is a Selectfluor-mediated fluorination/elimination sequence on phosphonylated exo-glycals, and it offers a new entry into fluorinated carbohydrate chemistry. The challenging E/Z stereochemical assignment of the resulting tetrasubstituted alkenes, which bear an alkoxy, an alkyl, a fluoro, and a phosphonyl group, has been achieved through NMR experiments. The corresponding (E)- and (Z)-nucleotide fluorosugars have been prepared and tested as inhibitors of UDP-galactopyranose mutase (UGM). UGM is a flavoenzyme that catalyzes the isomerization of uridine diphosphate(UDP)-galactopyranose into UDP-galactofuranose, a key step of the biosynthesis of important mycobacterial cell-wall glycoconjugates. The two diastereomeric molecules were found to display time-dependent inactivation of UGM, as expected from preliminary results using non-fluorinated exo-glycal nucleotides. The inhibitory properties of the two fluorinated molecules led us to suggest that the inactivation mechanism proceeds through two-electron processes, despite the presence of the flavin cofactor within the UGM catalytic site.
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Affiliation(s)
- Audrey Caravano
- Ecole Normale Supérieure, Département de Chimie, Institut de Chimie Moléculaire (FR 2769), UMR 8642: CNRS-ENS-UPMC Paris 6, 24 rue Lhomond, 75231 Paris Cedex 05, France
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Abstract
Strategies for the stereoselective synthesis of mycobacterial arabinan were explored. Arabinofuranosyl donors with various protective groups were screened in terms of suitability for beta-(1,2-cis)-selective glycosylation. The protective group was found to affect the stereoselectivity of arabinofuranosylation. Beta-selectivity was drastically enhanced by using donors protected with 3,5-TIDPS, possibly due to conformational constraints on the furanose ring. Synthesis of heptaarabinofuranoside was then performed to demonstrate the practicality of this methodology. [reaction: see text].
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Affiliation(s)
- Akihiro Ishiwata
- RIKEN (Institute of Physical and Chemical Research), Wako-shi, Saitama 351-0198, Japan
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Mansoorabadi SO, Thibodeaux CJ, Liu HW. The diverse roles of flavin coenzymes--nature's most versatile thespians. J Org Chem 2007; 72:6329-42. [PMID: 17580897 PMCID: PMC2519020 DOI: 10.1021/jo0703092] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Flavin coenzymes play a variety of roles in biological systems. This Perspective highlights the chemical versatility of flavins by reviewing research on five flavoenzymes that have been studied in our laboratory. Each of the enzymes discussed in this review [the acyl-CoA dehydrogenases (ACDs), CDP-6-deoxy-l-threo-d-glycero-4-hexulose-3-dehydrase reductase (E3), CDP-4-aceto-3,6-dideoxygalactose synthase (YerE), UDP-galactopyranose mutase (UGM), and type II isopentenyl diphosphate:dimethylallyl diphosphate isomerase (IDI-2)] utilizes flavin in a distinct role. In particular, the catalytic mechanisms of two of these enzymes, UGM and IDI-2, may involve novel flavin chemistry.
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Affiliation(s)
- Steven O. Mansoorabadi
- Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry and Biochemistry, University of Texas, Austin, TX 78712, USA
| | - Christopher J. Thibodeaux
- Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry and Biochemistry, University of Texas, Austin, TX 78712, USA
| | - Hung-wen Liu
- Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry and Biochemistry, University of Texas, Austin, TX 78712, USA
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Crich D, Pedersen CM, Bowers AA, Wink DJ. On the use of 3,5-O-benzylidene and 3,5-O-(di-tert-butylsilylene)-2-O-benzylarabinothiofuranosides and their sulfoxides as glycosyl donors for the synthesis of beta-arabinofuranosides: importance of the activation method. J Org Chem 2007; 72:1553-65. [PMID: 17286432 PMCID: PMC2617737 DOI: 10.1021/jo061440x] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A 2-O-benzyl-3,5-O-benzylidene-alpha-d-thioarabinofuranoside was obtained by reaction of the corresponding diol with alpha,alpha-dibromotoluene under basic conditions. On activation with 1-benzenesulfinyl piperidine, or diphenyl sulfoxide, and trifluoromethanesulfonic anhydride in dichloromethane at -55 degrees C, reaction with glycosyl acceptors affords anomeric mixtures with little or no selectivity. The analogous 2-O-benzyl-3,5-O-(di-tert-butylsilylene)-alpha-d-thioarabinofuranoside also showed no significant selectivity under the 1-benzenesulfinyl piperidine or diphenyl sulfoxide conditions. With N-iodosuccinimide and silver trifluoromethanesulfonate the silylene acetal showed moderate to high beta-selectivity, independent of the configuration of the starting thioglycoside. High beta-selectivity was also obtained with a 2-O-benzyl-3,5-O-(di-tert-butylsilylene)-alpha-arabinofuranosyl sulfoxide donor on activation with trifluoromethanesulfonic anhydride. The high beta-selectivities obtained by the N-iodosuccinimide/silver trifluoromethanesulfonate and sulfoxide methods are consistent with a common intermediate, most likely to be the oxacarbenium ion. The poor selectivity observed on activation of the thioglycosides with the 1-benzenesulfinyl piperidine, or diphenyl sulfoxide, and trifluoromethanesulfonic anhydride methods appears to be the result of the formation of a complex mixture of glycosyl donors, as determined by low-temperature NMR work.
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Affiliation(s)
- David Crich
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, IL 60607-7061, USA.
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Bai Y, Lowary TL. 2,3-Anhydrosugars in Glycoside Bond Synthesis. Application to α-d-Galactofuranosides. J Org Chem 2006; 71:9658-71. [PMID: 17168583 DOI: 10.1021/jo061713o] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report here the use of 2,3-anhydro-D-gulofuranosyl thioglycosides and glycosyl sulfoxides in the synthesis of alpha-D-galactofuranosidic bonds, which are present in a range of bacterial and fungal glycoconjugates. This two-step method involves a stereoselective glycosylation in which a 2,3-anhydro-alpha-D-gulofuranoside is obtained either as the sole or as the major product, followed by a regioselective opening of the epoxide ring using lithium benzylate in the presence of (-)-sparteine. In exploring the scope of the method, donors protected at O5 and O6 with an isopropylidene acetal, benzyl ethers, or benzoate esters were studied. Overall, the glycosyl sulfoxides provided the products in slightly higher yields and selectivity, with the best results being obtained with benzylated and benzoylated substrates. In the epoxide ring-opening reactions, the acetal- and ether-protected donors afforded poor to modest regioselectivity, whereas the benzoylated products gave good yields of the desired alpha-D-galactofuranosides. The benzoyl-protected species are, therefore, the donors of choice for these reactions. The utility of the approach was demonstrated through the synthesis of three alpha-D-galactofuranosyl-containing oligosaccharides.
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Affiliation(s)
- Yu Bai
- Alberta Ingenuity Centre for Carbohydrate Science and Department of Chemistry, The University of Alberta, Gunning-Lemieux Chemistry Centre, Edmonton, Alberta T6G 2G2, Canada
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Ishii T, Ono H, Ohnishi-Kameyama M, Maeda I. Enzymic transfer of alpha-L-arabinopyranosyl residues to exogenous 1,4-linked beta-D-galacto-oligosaccharides using solubilized mung bean (Vigna radiata) hypocotyl microsomes and UDP-beta-L-arabinopyranose. PLANTA 2005; 221:953-963. [PMID: 15846502 DOI: 10.1007/s00425-005-1504-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2004] [Accepted: 01/25/2005] [Indexed: 05/24/2023]
Abstract
A single alpha-L-arabinopyranosyl (alpha-L-Arap) residue was shown, by a combination of chemical and spectroscopic methods, to be transferred to O-4 of the nonreducing terminal galactosyl (Gal) residue of 2-aminobenzamide (2AB)-labeled galacto-oligosaccharides when these oligosaccharides were reacted with UDP-ss-L-arabinopyranose (UDP-ss-L-Arap) in the presence of a Triton X-100-soluble extract of microsomal membranes isolated from mung bean (Vigna radiata, L. Wilezek) hypocotyls. Maximum-(1-->4)-arabinopyranosyltransferase activity was obtained at pH 6.0-6.5 and 20 degrees C in the presence of 25 mM Mn2+. The enzyme had an apparent K m of 45 microM for the 2AB-labeled galactoheptasaccharide and 330 microM for UDP-ss-L-Arap. A series of 2AB-labeled galacto-oligosaccharides with a degree of polymerization (DP) between 6 and 10 that contained a single alpha-L-Arap residue linked to the former nonreducing terminal Gal residue were generated when the 2AB-labeled galactohexasaccharide (Gal6-2AB) was reacted with UDP- ss-L-Ara p in the presence of UDP-beta-D-Galp and the solubilized microsomal fraction. The mono-arabinosylated galacto-oligosaccharides are not acceptor substrates for the galactosyltransferase activities known to be present in mung bean microsomes. These results show that mung bean hypocotyl microsomes contain an enzyme that catalyzes the transfer of Arap to the nonreducing Gal residue of galacto-oligosaccharides and suggest that the presence of a alpha-L-Arap residue on the former terminal Gal residue prevents galactosylation of galacto-oligosaccharides.
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Affiliation(s)
- Tadashi Ishii
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan.
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36
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Euzen R, Ferrières V, Plusquellec D. General one-step synthesis of free hexofuranosyl 1-phosphates using unprotected 1-thioimidoyl hexofuranosides. J Org Chem 2005; 70:847-55. [PMID: 15675842 DOI: 10.1021/jo0484934] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A general one-step strategy is developed for the synthesis of hexofuranosyl 1-phosphates starting from new unprotected glycofuranosyl donors. It required first the preparation of new 1-thiohexofuranosides bearing a thioimidoyl heterocycle as a leaving group. The presence of sulfur and/or nitrogen atom(s) on the aglycon allowed remote activation of these thioglycofuranosides by anhydrous phosphoric acid and led to the target phosphates 9, 27, 29, and 30 in good to excellent selectivities and, more importantly, with very limited or no ring expansion. Moreover, this one-step phosphorylation reaction could be significantly improved by avoiding any tedious protecting group manipulations on negatively charged compounds and by focusing on a simple but general procedure of purification. This approach was applied to the diastereocontrolled synthesis of d-galacto- and d-glucofuranosyl 1-phosphates and also to the preparation of rare epimer and/or deoxy counterparts, that is, d-manno- and d-fucofuranosyl derivatives.
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Affiliation(s)
- Ronan Euzen
- Ecole Nationale Supérieure de Chimie de Rennes, UMR CNRS 6052 Synthèses et Activations de Biomolécules, Institut de Chimie de Rennes, Avenue du Général Leclerc, F-35700 Rennes, France
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Soltero-Higgin M, Carlson EE, Gruber TD, Kiessling LL. A unique catalytic mechanism for UDP-galactopyranose mutase. Nat Struct Mol Biol 2004; 11:539-43. [PMID: 15133501 DOI: 10.1038/nsmb772] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2003] [Accepted: 04/08/2004] [Indexed: 11/08/2022]
Abstract
The flavoenzyme uridine 5'-diphosphate (UDP)-galactopyranose mutase (UGM) catalyzes the interconversion of UDP-galactopyranose (UDP-Galp) and UDP-galactofuranose (UDP-Galf). The latter is an essential precursor to the cell wall arabinogalactan of Mycobacterium tuberculosis. The catalytic mechanism for this enzyme had not been elucidated. Here, we provide evidence for a mechanism in which the flavin cofactor assumes a new role. Specifically, the N5 of the reduced anionic flavin cofactor captures the anomeric position of the galactose residue with release of UDP. Interconversion of the isomers occurs via a flavin-derived iminium ion. To trap this putative intermediate, we treated UGM with radiolabeled UDP-Galp and sodium cyanoborohydride; a radiolabeled flavin-galactose adduct was obtained. Ultraviolet-visible spectroscopy and mass spectrometry indicate that this product is an N5-alkyl flavin. We anticipate that the clarification of the catalytic mechanism for UGM will facilitate the development of anti-mycobacterial agents.
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Smith DM, Woerpel KA. Using Stereoelectronic Effects to Explain Selective Reactions of 4-Substituted Five-Membered Ring Oxocarbenium Ions. Org Lett 2004; 6:2063-6. [PMID: 15176819 DOI: 10.1021/ol0492647] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] The utility of the inside attack model to predict and analyze the stereoselectivities of nucleophilic additions to complex five-membered ring oxocarbenium ions is demonstrated in a systematic study of C-4-substituted acetals.
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Affiliation(s)
- Deborah M Smith
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, USA
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Nunan KJ, Scheller HV. Solubilization of an arabinan arabinosyltransferase activity from mung bean hypocotyls. PLANT PHYSIOLOGY 2003; 132:331-42. [PMID: 12746538 PMCID: PMC166978 DOI: 10.1104/pp.102.019406] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2002] [Revised: 01/18/2003] [Accepted: 02/04/2003] [Indexed: 05/18/2023]
Abstract
The biosynthesis of polysaccharides destined for the plant cell wall and the subsequent assembly of the cell wall are poorly understood processes that are currently the focus of much research. Arabinan, a component of the pectic polysaccharide rhamnogalacturonan I, is composed of arabinosyl residues connected via various glycosidic linkages, and therefore, the biosynthesis of arabinan is likely to involve more than one arabinosyltransferase. We have studied the transfer of [(14)C]arabinose (Ara) from UDP-L-arabinopyranose onto polysaccharides using microsomal membranes isolated from mung bean (Vigna radiata) hypocotyls. [(14)C]arabinosyl and [(14)C]xylosyl residues were incorporated into endogenous products due to the presence of UDP-Xyl-4-epimerase activity. Enzymatic digestion of endogenous products with endo-arabinanase released very little radiolabeled sugars, whereas digestion with arabinofuranosidase released some [(14)C]Ara. Microsomal membranes solubilized with the detergent octyl glucoside were able to add a single [(14)C]Ara residue onto (1-->5)-linked alpha-L-arabino-oligosaccharide acceptors. The reaction had a pH optimum of 6.5 and a requirement for manganese ions. However, enzymatic digestion of the radiolabeled oligosaccharides with endo-arabinanase and arabinofuranosidases could not fully release the radiolabeled Ara residue, indicating that the [(14)C]Ara residue was not a (1-->2)-, (1-->3)-, or (1-->5)-linked alpha-L-arabinofuranosyl residue. Rather, mild acid treatment of the product suggested that the radiolabeled Ara residue was in a pyranose conformation, and this result was confirmed by thin-layer chromatography of radiolabeled partially methylated sugars. Using microsomal membranes separated on a discontinuous sucrose gradient, the arabinosyltransferase activity appears to be mainly localized to Golgi membranes.
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Affiliation(s)
- Kylie Joy Nunan
- Plant Biochemistry Laboratory, Department of Plant Biology, The Royal Veterinary and Agricultural University, 1871 Frederiksberg C, Copenhagen, Denmark
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Molinaro A, Piscopo V, Lanzetta R, Parrilli M. Structural determination of the complex exopolysaccharide from the virulent strain of Cryphonectria parasitica. Carbohydr Res 2002; 337:1707-13. [PMID: 12423948 DOI: 10.1016/s0008-6215(02)00283-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The structure of a new exopolysaccharide from the virulent strain of Cryphonectria parasitica was elucidated by means of 2D NMR spectroscopy and selective degradations (mild hydrolysis and acetolysis). The polysaccharide is built up of mannose, galactose and rhamnose and has a rather complex non-repetitive structure that can be idealised as follows:
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Affiliation(s)
- A Molinaro
- Dipartimento di Chimica Organica e Biochimica, Università di Napoli 'Federico II', via Cynthia 4, I-80126, Napoli, Italy.
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