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Ahangarpour M, Kavianinia I, Harris PWR, Brimble MA. Photo-induced radical thiol-ene chemistry: a versatile toolbox for peptide-based drug design. Chem Soc Rev 2021; 50:898-944. [PMID: 33404559 DOI: 10.1039/d0cs00354a] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
While the global market for peptide/protein-based therapeutics is witnessing significant growth, the development of peptide drugs remains challenging due to their low oral bioavailability, poor membrane permeability, and reduced metabolic stability. However, a toolbox of chemical approaches has been explored for peptide modification to overcome these obstacles. In recent years, there has been a revival of interest in photoinduced radical thiol-ene chemistry as a powerful tool for the construction of therapeutic peptides.
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Affiliation(s)
- Marzieh Ahangarpour
- School of Chemical Sciences, The University of Auckland, 23 Symonds Street, Auckland 1010, New Zealand.
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2
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Abstract
Glycosylation is one of the most prevalent posttranslational modifications that profoundly affects the structure and functions of proteins in a wide variety of biological recognition events. However, the structural complexity and heterogeneity of glycoproteins, usually resulting from the variations of glycan components and/or the sites of glycosylation, often complicates detailed structure-function relationship studies and hampers the therapeutic applications of glycoproteins. To address these challenges, various chemical and biological strategies have been developed for producing glycan-defined homogeneous glycoproteins. This review highlights recent advances in the development of chemoenzymatic methods for synthesizing homogeneous glycoproteins, including the generation of various glycosynthases for synthetic purposes, endoglycosidase-catalyzed glycoprotein synthesis and glycan remodeling, and direct enzymatic glycosylation of polypeptides and proteins. The scope, limitation, and future directions of each method are discussed.
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Affiliation(s)
- Chao Li
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Lai-Xi Wang
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
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3
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Petrelli A, Samain E, Pradeau S, Halila S, Fort S. Efficient Conjugation of Oligosaccharides to Polymer Particles through Furan/Maleimide Diels-Alder Reaction: Application to the Capture of Carbohydrate-Binding Proteins. Chembiochem 2016; 18:206-212. [DOI: 10.1002/cbic.201600509] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Indexed: 01/07/2023]
Affiliation(s)
- Antoine Petrelli
- Université Grenoble Alpes; CERMAV; 38000 Grenoble France
- CNRS; CERMAV; 38000 Grenoble France
| | - Eric Samain
- Université Grenoble Alpes; CERMAV; 38000 Grenoble France
- CNRS; CERMAV; 38000 Grenoble France
| | - Stéphanie Pradeau
- Université Grenoble Alpes; CERMAV; 38000 Grenoble France
- CNRS; CERMAV; 38000 Grenoble France
| | - Sami Halila
- Université Grenoble Alpes; CERMAV; 38000 Grenoble France
- CNRS; CERMAV; 38000 Grenoble France
| | - Sébastien Fort
- Université Grenoble Alpes; CERMAV; 38000 Grenoble France
- CNRS; CERMAV; 38000 Grenoble France
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Abstract
Amides are widespread in biologically active compounds with a broad range of applications in biotechnology, agriculture and medicine. Therefore, as alternative to chemical synthesis the biocatalytic amide synthesis is a very interesting field of research. As usual, Nature can serve as guide in the quest for novel biocatalysts. Several mechanisms for carboxylate activation involving mainly acyl-adenylate, acyl-phosphate or acyl-enzyme intermediates have been discovered, but also completely different pathways to amides are found. In addition to ribosomes, selected enzymes of almost all main enzyme classes are able to synthesize amides. In this review we give an overview about amide synthesis in Nature, as well as biotechnological applications of these enzymes. Moreover, several examples of biocatalytic amide synthesis are given.
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McSweeney L, Dénès F, Scanlan EM. Thiyl-Radical Reactions in Carbohydrate Chemistry: From Thiosugars to Glycoconjugate Synthesis. European J Org Chem 2016. [DOI: 10.1002/ejoc.201501543] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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6
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Gorges J, Kazmaier U. BEt3-Initiated Thiol-Ene Click Reactions as a Versatile Tool To Modify Sensitive Substrates. European J Org Chem 2015. [DOI: 10.1002/ejoc.201500915] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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7
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Richard M, Didierjean C, Chapleur Y, Pellegrini-Moïse N. Base- and Radical-Mediated Regio- and Stereoselective Additions of Thiols, Thio-Sugars, and Thiol-Containing Peptides to Trisubstituted Activatedexo-Glycals. European J Org Chem 2015. [DOI: 10.1002/ejoc.201500130] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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8
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Goswami A, Van Lanen SG. Enzymatic strategies and biocatalysts for amide bond formation: tricks of the trade outside of the ribosome. MOLECULAR BIOSYSTEMS 2014; 11:338-53. [PMID: 25418915 DOI: 10.1039/c4mb00627e] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Amide bond-containing (ABC) biomolecules are some of the most intriguing and functionally significant natural products with unmatched utility in medicine, agriculture and biotechnology. The enzymatic formation of an amide bond is therefore a particularly interesting platform for engineering the synthesis of structurally diverse natural and unnatural ABC molecules for applications in drug discovery and molecular design. As such, efforts to unravel the mechanisms involved in carboxylate activation and substrate selection has led to the characterization of a number of structurally and functionally distinct protein families involved in amide bond synthesis. Unlike ribosomal synthesis and thio-templated synthesis using nonribosomal peptide synthetases, which couple the hydrolysis of phosphoanhydride bond(s) of ATP and proceed via an acyl-adenylate intermediate, here we discuss two mechanistically alternative strategies: ATP-dependent enzymes that generate acylphosphate intermediates and ATP-independent transacylation strategies. Several examples highlighting the function and synthetic utility of these amide bond-forming strategies are provided.
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Affiliation(s)
- Anwesha Goswami
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 S. Limestone, Lexington, KY 40536, USA.
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9
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Karmann L, Kazmaier U. Thiol-Ene Click Reactions - Versatile Tools for the Modification of Unsaturated Amino Acids and Peptides. European J Org Chem 2013. [DOI: 10.1002/ejoc.201300672] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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10
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Hayes TR, Lyon PA, Silva-Lopez E, Twamley B, Benny PD. Photo-initiated thiol-ene click reactions as a potential strategy for incorporation of [M(I)(CO)3]+ (M = Re, (99m)Tc) complexes. Inorg Chem 2013; 52:3259-67. [PMID: 23445468 DOI: 10.1021/ic302771f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Click reactions offer a rapid technique to covalently assemble two molecules. In radiopharmaceutical construction, these reactions can be utilized to combine a radioactive metal complex with a biological targeting molecule to yield a potent tool for imaging or therapy applications. The photo-initiated radical thiol-ene click reaction between a thiol and an alkene was examined for the incorporation of [M(I)(CO)3](+) (M = Re, (99m)Tc) systems for conjugating biologically active targeting molecules containing a thiol. In this strategy, a potent chelate system, 2,2'-dipicolylamine (DPA), for [M(I)(CO)3](+) was functionalized at the central amine with a terminal alkene linker that was explored with two synthetic approaches, click then chelate and chelate then click, to determine the flexibility and applicability of the thiol-ene click reaction to specifically incorporate ligand systems and metal complexes with a thiol containing molecule. In the click then chelate approach, the thiol-ene click reaction was carried out with the DPA chelate followed by complexation with [M(I)(CO)3](+). In the chelate then click approach, the alkene functionalized DPA chelate was first complexed with [M(I)(CO)3](+) followed by the conduction of the thiol-ene click reaction. Initial studies utilized benzyl mercaptan as a model thiol for both strategies to generate the identical product from either route to provide information on reactivity and product formation. DPA ligands functionalized with two unique linker systems (allyl and propyl allyl ether) were prepared to examine the effect of the proximity of the chelate or complex on the thiol-ene click reaction. Both the thiol-ene click and coordination reactions with Re, (99m)Tc were performed in moderate to high yields demonstrating the potential of the thiol-ene click reaction for [M(I)(CO)3](+) incorporation into thiol containing biomolecules.
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Affiliation(s)
- Thomas R Hayes
- Department of Chemistry, Washington State University, P.O. Box 644630, Pullman, Washington 99164, USA
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11
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Mercey G, Reboul V, Gulea M, Levillain J, Gaumont AC. Synthetic Methodologies for the Preparation of β-Amino Thiols. European J Org Chem 2012. [DOI: 10.1002/ejoc.201200347] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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12
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Dondoni A, Marra A. Recent applications of thiol–ene coupling as a click process for glycoconjugation. Chem Soc Rev 2012; 41:573-86. [DOI: 10.1039/c1cs15157f] [Citation(s) in RCA: 244] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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13
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Kobayashi S, Makino A. Enzymatic polymer synthesis: an opportunity for green polymer chemistry. Chem Rev 2010; 109:5288-353. [PMID: 19824647 DOI: 10.1021/cr900165z] [Citation(s) in RCA: 409] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Shiro Kobayashi
- R & D Center for Bio-based Materials, Kyoto Institute of Technology, Kyoto 606-8585, Japan.
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14
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Dondoni A, Massi A, Nanni P, Roda A. A New Ligation Strategy for Peptide and Protein Glycosylation: Photoinduced Thiol-Ene Coupling. Chemistry 2009; 15:11444-9. [DOI: 10.1002/chem.200901746] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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15
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Dinkelaar J, de Jong AR, van Meer R, Somers M, Lodder G, Overkleeft HS, Codée JDC, van der Marel GA. Stereodirecting effect of the pyranosyl C-5 substituent in glycosylation reactions. J Org Chem 2009; 74:4982-91. [PMID: 19489535 DOI: 10.1021/jo900662v] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The stereodirecting effect of the glycosyl C-5 substituent has been investigated in a series of d-pyranosyl thioglycoside donors and related to their preferred positions in the intermediate (3)H(4) and (4)H(3) half-chair oxacarbenium ions. Computational studies showed that an axially positioned C-5 carboxylate ester can stabilize the (3)H(4) half-chair oxacarbenium ion conformer by donating electron density from its carbonyl function into the electron-poor oxacarbenium ion functionality. A similar stabilization can be achieved by a C-5 benzyloxymethyl group, but the magnitude of this stabilization is significantly smaller than for the C-5 carboxylate ester. As a result, the preference of the C-5 benzyloxymethyl to occupy an axial position in the half-chair oxacarbenium ions is much reduced compared to the C-5 carboxylate ester. To minimize steric interactions, a C-5 methyl group prefers to adopt an equatorial position and therefore favors the (4)H(3) half-chair oxacarbenium ion. When all pyranosyl substituents occupy their favored position in one of the two intermediate half-chair oxacarbenium ions, highly stereoselective glycosylations can be achieved as revealed by the excellent beta-selectivity of mannuronate esters and alpha-selectivity of 6-deoxygulosides.
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Affiliation(s)
- Jasper Dinkelaar
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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16
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Fiore M, Marra A, Dondoni A. Photoinduced Thiol−Ene Coupling as a Click Ligation Tool for Thiodisaccharide Synthesis. J Org Chem 2009; 74:4422-5. [DOI: 10.1021/jo900514w] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Michele Fiore
- Dipartmento di Chimica, Laboratorio di Chimica Organica, Università di Ferrara, Via L. Borsari 46, 44100 Ferrara, Italy
| | - Alberto Marra
- Dipartmento di Chimica, Laboratorio di Chimica Organica, Università di Ferrara, Via L. Borsari 46, 44100 Ferrara, Italy
| | - Alessandro Dondoni
- Dipartmento di Chimica, Laboratorio di Chimica Organica, Università di Ferrara, Via L. Borsari 46, 44100 Ferrara, Italy
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17
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Affiliation(s)
- David P Gamblin
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, United Kingdom
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18
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Hackenberger C, Schwarzer D. Chemoselektive Ligations- und Modifikationsstrategien für Peptide und Proteine. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200801313] [Citation(s) in RCA: 204] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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19
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Hackenberger C, Schwarzer D. Chemoselective Ligation and Modification Strategies for Peptides and Proteins. Angew Chem Int Ed Engl 2008; 47:10030-74. [DOI: 10.1002/anie.200801313] [Citation(s) in RCA: 651] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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20
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Dondoni A. The Emergence of Thiol-Ene Coupling as a Click Process for Materials and Bioorganic Chemistry. Angew Chem Int Ed Engl 2008; 47:8995-7. [DOI: 10.1002/anie.200802516] [Citation(s) in RCA: 547] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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21
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Dondoni A. Die Entwicklung der Thiol-En-Kupplung als Klick-Prozess für die Materialwissenschaften und die bioorganische Chemie. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200802516] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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22
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Mercey G, Brégeon D, Gaumont AC, Levillain J, Gulea M. Efficient synthesis of primary 2-aminothiols from 2-aminoalcohols and methyldithioacetate. Tetrahedron Lett 2008. [DOI: 10.1016/j.tetlet.2008.09.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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23
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Wittrock S, Becker T, Kunz H. Synthetic Vaccines of Tumor-Associated Glycopeptide Antigens by Immune-Compatible Thioether Linkage to Bovine Serum Albumin. Angew Chem Int Ed Engl 2007; 46:5226-30. [PMID: 17546719 DOI: 10.1002/anie.200700964] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Sven Wittrock
- Institut für Organische Chemie, Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
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Wittrock S, Becker T, Kunz H. Synthetische Vakzine aus tumorassoziierten Glycopeptidantigenen durch immunkompatible Verankerung über Thioether an Rinderserumalbumin. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200700964] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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25
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Zhang Y, Yao Q, Xia C, Jiang X, Wang PG. Trapping Norovirus by Glycosylated Hydrogels: a Potential Oral Antiviral Drug. ChemMedChem 2006; 1:1361-6. [PMID: 17042040 DOI: 10.1002/cmdc.200600135] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Yalong Zhang
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
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Fort S, Birikaki L, Dubois MP, Antoine T, Samain E, Driguez H. Biosynthesis of conjugatable saccharidic moieties of GM2 and GM3 gangliosides by engineered E. coli. Chem Commun (Camb) 2005:2558-60. [PMID: 15900325 DOI: 10.1039/b500686d] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Oligosaccharidic moieties of GM(2) and GM(3) gangliosides bearing an allyl or a propargyl aglycon, are efficiently biosynthesized on the gram scale by growing metabolically engineered Escherichia coli cells in the presence of the corresponding lactoside acceptors and sialic acid.
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Affiliation(s)
- Sébastien Fort
- Centre de Recherches sur les Macromolécules Végétales, CERMAV-FR-CNRS 2607, affiliated to Université Joseph Fourier Grenoble, BP 53, 38041 Grenoble Cedex 9, France.
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27
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Sato M, Furuike T, Sadamoto R, Fujitani N, Nakahara T, Niikura K, Monde K, Kondo H, Nishimura SI. Glycoinsulins: Dendritic Sialyloligosaccharide-Displaying Insulins Showing a Prolonged Blood-Sugar-Lowering Activity. J Am Chem Soc 2004; 126:14013-22. [PMID: 15506764 DOI: 10.1021/ja046426l] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mono-, di-, and trisialyloligosaccharides were introduced to mutant insulins through enzymatic reactions. Sugar chains were sialylated by alpha2,6-sialyltransferase (alpha2,6-SiaT) via an accessible glutamine residue at the N-terminus of the B-chain attached by transglutaminase (TGase). Sia2,6-di-LacNAc-Ins(B-F1Q) and Sia2,6-tri-LacNAc-Ins(B-F1Q), displaying two and three sialyl-N-acetyllactosamines, respectively, were administered to hyperglycemic mice. Both branched glycoinsulins showed prolonged glucose-lowering effects compared to native or lactose-carrying insulins, showing that sialic acid is important in obtaining a prolonged effect. Sia2,6-tri-LacNAc-Ins(B-F1Q), in particular, induced a significant delay in the recovery of glucose levels.
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Affiliation(s)
- Masaaki Sato
- Division of Biological Sciences, Graduate School of Science, Frontier Research Center for Post-Genomic Science and Technology, Hokkaido University, Kita 21 Nishi 11, Sapporo 001-0021, Japan
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28
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Naicker KP, Li H, Heredia A, Song H, Wang LX. Design and synthesis of αGal-conjugated peptide T20 as novel antiviral agent for HIV-immunotargeting. Org Biomol Chem 2004; 2:660-4. [PMID: 14985805 DOI: 10.1039/b313844e] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An efficient chemo-enzymatic synthesis of alpha Gal-conjugated peptide T20 as novel HIV-immuno-targeting agent is described. The synthesis involves chemo-enzymatic preparation of maleimide-functionalized alpha Gal epitope and its chemoselective ligation with the peptide T20. The title compound contains two functional domains: the trisaccharide alpha Gal epitope that binds to human natural anti-Gal antibodies and the 36-amino acid gp41 peptide (T20) that recognizes the gp41 N-terminal ectodomain of the HIV envelope. Biological assays demonstrated that the synthetic conjugate could readily bind to natural anti-Gal antibodies (both IgG and IgM type) in normal human serum and exhibited potent anti-HIV activity even in the absence of human antibodies and complement system. The experimental data suggest that the synthetic alpha Gal-T20 might be valuable for in vivo HIV-immuno-targeting via antibody-mediated cytotoxicity and/or antibody-dependent, complement-mediated lysis of HIV particles and HIV-infected cells, thus providing an additional dimension of HIV intervention.
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Affiliation(s)
- Kannan P Naicker
- Institute of Human Virology, University of Maryland Biotechnology Institute, University of Maryland, Baltimore, MD 21201, USA
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29
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Mogemark M, Elofsson M, Kihlberg J. Solid-phase synthesis of alpha-Gal epitopes: on-resin analysis of solid-phase oligosaccharide synthesis with 19F NMR spectroscopy. J Org Chem 2003; 68:7281-8. [PMID: 12968877 DOI: 10.1021/jo034581x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A route for solid-phase synthesis of the alpha-Gal epitopes Gal(alpha1-3)Gal(beta1-4)Glc and Gal(alpha1-3)Gal(beta1-4)GlcNAc is described. These trisaccharide antigens are responsible for hyperacute rejection in xenotransplantation of porcine organs. Optimization of the solid-phase synthesis relied on use of fluorinated protective groups for the carbohydrate building blocks and use of a fluorinated linker. This allowed convenient on-resin analysis of the reactions with gel-phase (19)F NMR spectroscopy. Conditions were established which allowed reductive ring-opening of 4,6-O-benzylidene acetals to be performed on the solid phase with high regioselectivity to furnish the corresponding 6-O-benzyl ethers. It was found that glycosylations could be conveniently carried out by using thioglycosides as donors with N-iodosuccinimide and trifluoromethanesulfonic acid as the promoter system. With use of these conditions a challenging alpha-glycosidic linkage was successfully installed with complete stereoselectivity in the final glycosylation. It was also established that fluorinated benzoates, benzyl ethers, and benzylidene acetals display almost identical chemical properties as their nonfluorinated counterparts, a finding that is essential for future use of fluorinated protective groups in solid-phase oligosaccharide synthesis.
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Affiliation(s)
- Mickael Mogemark
- Organic Chemistry, Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden, and AstraZeneca R&D Mölndal, SE-431 83 Mölndal, Sweden
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31
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Simas ABC, Pais KC, da Silva AAT. A more convenient and general procedure for O-monobenzylation of diols via stannylenes: a critical reevaluation of the Bu2SnO method. J Org Chem 2003; 68:5426-8. [PMID: 12816515 DOI: 10.1021/jo026794c] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A more consistent, straightforward, and economical protocol for generation of stannylene species and their reaction with BnBr leading to products of O-monobenzylation of diols has been set. It has shown to be specially indicated for substrates bearing vicinal trans 1,2-diol moieties on cyclohexane backbones, which are more resistant to these transformations. Such protocol has been successfully applied to myo-inositol derivatives and acyclic diols.
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Affiliation(s)
- Alessandro B C Simas
- Universidade Federal do Rio de Janeiro, Núcleo de Pesquisas de Produtos Naturais (NPPN), Laboratório Roderick A. Barnes, Ilha da Cidade Universitária, CCS, bloco H, Rio de Janeiro RJ 21941-590, Brazil.
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32
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Affiliation(s)
- Benjamin G Davis
- Dyson Perrins Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QY, UK.
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