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Obst F, Mertz M, Mehner PJ, Beck A, Castiglione K, Richter A, Voit B, Appelhans D. Enzymatic Synthesis of Sialic Acids in Microfluidics to Overcome Cross-Inhibitions and Substrate Supply Limitations. ACS Appl Mater Interfaces 2021; 13:49433-49444. [PMID: 34612033 DOI: 10.1021/acsami.1c12307] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Multienzymatic cascade reactions are a powerful strategy for straightforward and highly specific synthesis of complex materials, such as active substances in drugs. Cross-inhibitions and incompatible reaction steps, however, often limit enzymatic activity and thus the conversion. Such limitations occur, e.g., in the enzymatic synthesis of the biologically active sialic acid cytidine monophosphate N-acetylneuraminic acid (CMP-Neu5Ac). We addressed this challenge by developing a confinement and compartmentalization concept of hydrogel-immobilized enzymes for improving the efficiency of the enzyme cascade reaction. The three enzymes required for the synthesis of CMP-Neu5Ac, namely, N-acyl-d-glucosamine 2-epimerase (AGE), N-acetylneuraminate lyase (NAL), and CMP-sialic acid synthetase (CSS), were immobilized into bulk hydrogels and microstructured hydrogel-enzyme-dot arrays, which were then integrated into microfluidic devices. To overcome the cytidine triphosphate (CTP) cross-inhibition of AGE and NAL, only a low CTP concentration was applied and continuously conveyed through the device. In a second approach, the enzymes were compartmentalized in separate reaction chambers of the microfluidic device to completely avoid cross-inhibitions and enable the use of higher substrate concentrations. Immobilization efficiencies of up to 25% and pronounced long-term activity of the immobilized enzymes for several weeks were realized. Moreover, immobilized enzymes were less sensitive to inhibition and the substrate-channeling effect between immobilized enzymes promoted the overall conversion in the trienzymatic cascade reaction. Based on this, CMP-Neu5Ac was successfully synthesized by immobilized enzymes in noncompartmentalized and compartmentalized microfluidic devices. This study demonstrates the high potential of immobilizing enzymes in (compartmentalized) microfluidic devices to perform multienzymatic cascade reactions despite cross-inhibitions under continuous flow conditions. Due to the ease of enzyme immobilization in hydrogels, this concept is likely applicable for many cascade reactions with or without cross-inhibition characteristics.
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Affiliation(s)
- Franziska Obst
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
- Organische Chemie der Polymere, Technische Universität Dresden, Mommsenstraße 4, 01062 Dresden, Germany
| | - Michael Mertz
- Lehrstuhl für Bioverfahrenstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Paul-Gordan-Straße 3, 91052 Erlangen, Germany
| | - Philipp J Mehner
- Institut für Halbleiter- und Mikrosystemtechnik, Technische Universität Dresden, Nöthnitzer Straße 64, 01187 Dresden, Germany
| | - Anthony Beck
- Institut für Halbleiter- und Mikrosystemtechnik, Technische Universität Dresden, Nöthnitzer Straße 64, 01187 Dresden, Germany
| | - Kathrin Castiglione
- Lehrstuhl für Bioverfahrenstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Paul-Gordan-Straße 3, 91052 Erlangen, Germany
| | - Andreas Richter
- Institut für Halbleiter- und Mikrosystemtechnik, Technische Universität Dresden, Nöthnitzer Straße 64, 01187 Dresden, Germany
| | - Brigitte Voit
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
- Organische Chemie der Polymere, Technische Universität Dresden, Mommsenstraße 4, 01062 Dresden, Germany
| | - Dietmar Appelhans
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
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Khedri Z, Xiao A, Yu H, Landig CS, Li W, Diaz S, Wasik BR, Parrish CR, Wang LP, Varki A, Chen X. A Chemical Biology Solution to Problems with Studying Biologically Important but Unstable 9-O-Acetyl Sialic Acids. ACS Chem Biol 2017; 12:214-224. [PMID: 27936566 PMCID: PMC5704959 DOI: 10.1021/acschembio.6b00928] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
9-O-Acetylation is a common natural modification on sialic acids (Sias) that terminate many vertebrate glycan chains. This ester group has striking effects on many biological phenomena, including microbe-host interactions, complement action, regulation of immune responses, sialidase action, cellular apoptosis, and tumor immunology. Despite such findings, 9-O-acetyl sialoglycoconjugates have remained largely understudied, primarily because of marked lability of the 9-O-acetyl group to even small pH variations and/or the action of mammalian or microbial esterases. Our current studies involving 9-O-acetylated sialoglycans on glycan microarrays revealed that even the most careful precautions cannot ensure complete stability of the 9-O-acetyl group. We now demonstrate a simple chemical biology solution to many of these problems by substituting the oxygen atom in the ester with a nitrogen atom, resulting in sialic acids with a chemically and biologically stable 9-N-acetyl group. We present an efficient one-pot multienzyme method to synthesize a sialoglycan containing 9-acetamido-9-deoxy-N-acetylneuraminic acid (Neu5Ac9NAc) and compare it to the one with naturally occurring 9-O-acetyl-N-acetylneuraminic acid (Neu5,9Ac2). Conformational resemblance of the two molecules was confirmed by computational molecular dynamics simulations. Microarray studies showed that the Neu5Ac9NAc-sialoglycan is a ligand for viruses naturally recognizing Neu5,9Ac2, with a similar affinity but with much improved stability in handling and study. Feeding of Neu5Ac9NAc or Neu5,9Ac2 to mammalian cells resulted in comparable incorporation and surface expression as well as binding to 9-O-acetyl-Sia-specific viruses. However, cells fed with Neu5Ac9NAc remained resistant to viral esterases and showed a slower turnover. This simple approach opens numerous research opportunities that have heretofore proved intractable.
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Affiliation(s)
- Zahra Khedri
- Glycobiology Research and Training Center, University of California, San Diego, CA 92093, USA
| | - An Xiao
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | - Hai Yu
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | - Corinna Susanne Landig
- Glycobiology Research and Training Center, University of California, San Diego, CA 92093, USA
| | - Wanqing Li
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | - Sandra Diaz
- Glycobiology Research and Training Center, University of California, San Diego, CA 92093, USA
| | - Brian R. Wasik
- Department of Microbiology and Immunology, Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Colin R. Parrish
- Department of Microbiology and Immunology, Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Lee-Ping Wang
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | - Ajit Varki
- Glycobiology Research and Training Center, University of California, San Diego, CA 92093, USA
| | - Xi Chen
- Department of Chemistry, University of California, Davis, CA 95616, USA
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St-Pierre G, Pal S, Østergaard ME, Zhou T, Yu J, Tanowitz M, Seth PP, Hanessian S. Synthesis and biological evaluation of sialyl-oligonucleotide conjugates targeting leukocyte B trans-membranal receptor CD22 as delivery agents for nucleic acid drugs. Bioorg Med Chem 2016; 24:2397-2409. [PMID: 27117693 DOI: 10.1016/j.bmc.2016.03.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 03/16/2016] [Accepted: 03/27/2016] [Indexed: 01/27/2023]
Abstract
Antisense oligonucleotides (ASOs) modified with ligands which target cell surface receptors have the potential to significantly improve potency in the target tissue. This has recently been demonstrated using triantennary N-acetyl d-galactosamine conjugated ASOs. CD22 is a cell surface receptor expressed exclusively on B cells thus presenting an attractive target for B cell specific delivery of drugs. Herein, we reported the synthesis of monovalent and trivalent ASO conjugates with biphenylcarbonyl (BPC) modified sialic acids and their study as ASO delivery agents into B cells. CD22 positive cells exhibited reduced potency when treated with ligand modified ASOs and mechanistic examination suggested reduced uptake into cells potentially as a result of sequestration of ASO by other cell-surface proteins.
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Affiliation(s)
- Gabrielle St-Pierre
- Department of Chemistry, Université de Montréal, PO Box 6128, Succ., Centre-ville, Montréal, Québec H3C 3J7, Canada
| | - Sudip Pal
- Department of Chemistry, Université de Montréal, PO Box 6128, Succ., Centre-ville, Montréal, Québec H3C 3J7, Canada
| | - Michael E Østergaard
- Medicinal Chemistry, Ionis Pharmaceuticals, Inc., 2855 Gazelle Court, Carlsbad, CA 92010, United States
| | - Tianyuan Zhou
- Medicinal Chemistry, Ionis Pharmaceuticals, Inc., 2855 Gazelle Court, Carlsbad, CA 92010, United States
| | - Jinghua Yu
- Medicinal Chemistry, Ionis Pharmaceuticals, Inc., 2855 Gazelle Court, Carlsbad, CA 92010, United States
| | - Michael Tanowitz
- Medicinal Chemistry, Ionis Pharmaceuticals, Inc., 2855 Gazelle Court, Carlsbad, CA 92010, United States
| | - Punit P Seth
- Medicinal Chemistry, Ionis Pharmaceuticals, Inc., 2855 Gazelle Court, Carlsbad, CA 92010, United States.
| | - Stephen Hanessian
- Department of Chemistry, Université de Montréal, PO Box 6128, Succ., Centre-ville, Montréal, Québec H3C 3J7, Canada.
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Mbua NE, Li X, Flanagan-Steet HR, Meng L, Aoki K, Moremen KW, Wolfert MA, Steet R, Boons GJ. Selective exo-enzymatic labeling of N-glycans on the surface of living cells by recombinant ST6Gal I. Angew Chem Int Ed Engl 2013; 52:13012-5. [PMID: 24129959 PMCID: PMC3869382 DOI: 10.1002/anie.201307095] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Indexed: 11/08/2022]
Abstract
A game of tag: N-Glycans on the surface of living cells were selectively tagged by exogenously administering recombinant ST6Gal I sialyltransferase and azide-modified CMP-Neu5Ac. This modification was followed by a strain-promoted cycloaddition using a biotin-modified dibenzylcyclooctynol (red star=biotin). The methodology will make it possible to dissect the mechanisms that underlie altered glycoconjugate recycling and storage in disease.
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Affiliation(s)
- Ngalle Eric Mbua
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 (USA), Fax: (+1) 706-542-4412
- Department of Chemistry, University of Georgia, 315 Riverbend Road, Athens, GA 30602 (USA), Fax: (+1) 706-542-4412
| | - Xiuru Li
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 (USA), Fax: (+1) 706-542-4412
| | - Heather R. Flanagan-Steet
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 (USA), Fax: (+1) 706-542-4412
| | - Lu Meng
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 (USA), Fax: (+1) 706-542-4412
| | - Kazuhiro Aoki
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 (USA), Fax: (+1) 706-542-4412
| | - Kelley W. Moremen
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 (USA), Fax: (+1) 706-542-4412
- Department of Biochemistry and Molecular Biology, University of Georgia, 315 Riverbend Road, Athens, GA 30602 (USA), Fax: (+1) 706-542-4412
| | - Margreet A. Wolfert
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 (USA), Fax: (+1) 706-542-4412
| | - Richard Steet
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 (USA), Fax: (+1) 706-542-4412
- Department of Biochemistry and Molecular Biology, University of Georgia, 315 Riverbend Road, Athens, GA 30602 (USA), Fax: (+1) 706-542-4412
| | - Geert-Jan Boons
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 (USA), Fax: (+1) 706-542-4412
- Department of Chemistry, University of Georgia, 315 Riverbend Road, Athens, GA 30602 (USA), Fax: (+1) 706-542-4412
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Zhang R, Jain S, Rowland M, Hussain N, Agarwal M, Gregoriadis G. Development and testing of solid dose formulations containing polysialic acid insulin conjugate: next generation of long-acting insulin. J Diabetes Sci Technol 2010; 4:532-9. [PMID: 20513317 PMCID: PMC2901028 DOI: 10.1177/193229681000400305] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND The need for lifelong, daily insulin injections can have a dramatic effect on patient compliance, can be painful, and runs the risk of local infections. Furthermore, needle-stick injuries are common, and the issue of needle disposal is troublesome. Injecting a long-acting insulin analog with needle-free administration would be a significant improvement for diabetic subjects, but is not currently feasible. To achieve a constant, reliable delivery of a novel, long-acting insulin analog, Lipoxen's SuliXen (polysialylated insulin) in a solid dosage form capable of being delivered without a needle has been developed. The aim of this study was to evaluate the feasibility of Lipoxen's SuliXen delivery with the Glide solid dose injector, Glide SDI. MATERIALS AND METHODS A formulation containing 14 kDa polysialic acid (PSA)-recombinant human insulin conjugate was manufactured at Lipoxen PLC and transferred to Glide Pharma. The PSA-insulin conjugate solution was incorporated into different excipients at Glide Pharma (excipients 1 and 2), and formulations were manufactured containing implants with doses of 0.3 and 1.0 IU of insulin, respectively. Two different polymeric excipients were investigated for their suitable release profiles. The physicomechanical properties of the formulations were characterized in terms of solid dosage form strength (via three-point bend and compression) and disintegration time at 37 degrees C. A preclinical efficacy study was performed in a nondiabetic rat model (Sprague-Dawley). RESULTS The study demonstrated successful incorporation of PSA-insulin conjugate into formulations compatible for use with the solid dose injector. Physicochemical characterization indicated that each formulation produced was physically robust. For excipient 1, the compressive stress and three-point-bend-test values recorded for the 0.3 IU formulation were 106.99 +/- 14.3 MPa and 30.6 +/- 1.4 N (force in newtons), respectively. Corresponding values for the 1.0 IU dose were 53.10 +/- 10.2 MPa and 16.66 +/- 1.0 N. For excipient 2, the compressive stress and three-point-bend-test values recorded for the 0.3 IU dose were 53.10 +/- 10.2 MPa and 7.64 +/- 0.9 N, respectively, whereas the corresponding values recorded for the 1.0 IU dose were 41.61 +/- 7.4 MPa and 13.18 +/- 1.3 N. Each formulation successfully penetrated a laboratory substrate, achieving 100% penetration in each case. In vivo analysis demonstrated that PSA-insulin conjugate shows prolongation of activity (at least two-fold more compared to insulin) for more than 5 hours in the rat model. CONCLUSION Even though additional work may be required, for example, to develop several fixed dose formulations, the preliminary results show that solid dosage forms incorporating PSA-insulin conjugate maintained the prolongation of PSA-insulin conjugate activity in the rat model. Convenient and easy to use, the solid dose injector will not only ensure diabetic patient compliance and trust but also provide cost-effective solutions for safe, reliable, and controlled needle-free injection of PSA-insulin conjugate.
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Affiliation(s)
- Rongsheng Zhang
- Lipoxen PLC, London Bioscience Innovation CentreLondon, United Kingdom
| | - Sanjay Jain
- Lipoxen PLC, London Bioscience Innovation CentreLondon, United Kingdom
| | - Martin Rowland
- Glide Pharmaceutical Technologies Limited, AbingdonOxfordshire, United Kingdom
| | - Nasir Hussain
- Glide Pharmaceutical Technologies Limited, AbingdonOxfordshire, United Kingdom
| | - Mohak Agarwal
- Lipoxen PLC, London Bioscience Innovation CentreLondon, United Kingdom
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Abstract
Sialic acids are a subset of nonulosonic acids, which are nine-carbon alpha-keto aldonic acids. Natural existing sialic acid-containing structures are presented in different sialic acid forms, various sialyl linkages, and on diverse underlying glycans. They play important roles in biological, pathological, and immunological processes. Sialobiology has been a challenging and yet attractive research area. Recent advances in chemical and chemoenzymatic synthesis, as well as large-scale E. coli cell-based production, have provided a large library of sialoside standards and derivatives in amounts sufficient for structure-activity relationship studies. Sialoglycan microarrays provide an efficient platform for quick identification of preferred ligands for sialic acid-binding proteins. Future research on sialic acid will continue to be at the interface of chemistry and biology. Research efforts not only will lead to a better understanding of the biological and pathological importance of sialic acids and their diversity but also could lead to the development of therapeutics.
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Affiliation(s)
- Xi Chen
- Department of Chemistry, University of California, Davis, California 95616, USA.
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Affiliation(s)
- Fabian Pfrengle
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany
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Yu H, Chokhawala H, Huang S, Chen X. One-pot three-enzyme chemoenzymatic approach to the synthesis of sialosides containing natural and non-natural functionalities. Nat Protoc 2007; 1:2485-92. [PMID: 17406495 PMCID: PMC2586341 DOI: 10.1038/nprot.2006.401] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Chemoenzymatic synthesis, which combines the flexibility of chemical synthesis and the high selectivity of enzymatic synthesis, is a powerful approach to obtain complex carbohydrates. It is a preferred method for synthesizing sialic acid-containing structures, including those with diverse naturally occurring and non-natural sialic acid forms, different sialyl linkages and different glycans that link to the sialic acid. Starting from N-acetylmannosamine, mannose or their chemically or enzymatically modified derivatives, sialic acid aldolase-catalyzed condensation reaction leads to the formation of sialic acids and their derivatives. These compounds are subsequently activated by a CMP-sialic acid synthetase and transferred to a wide range of suitable acceptors by a suitable sialyltransferase for the formation of sialosides containing natural and non-natural functionalities. The three-enzyme coupled synthesis of sialosides can be carried out in one pot without the isolation of intermediates. The time for synthesis is 4-18 h. Purification and characterization of the product can be completed within 2-3 d.
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Affiliation(s)
| | | | | | - Xi Chen
- Correspondence should be addressed to X.C. , Tel: 530-754-6037; Fax: 530-752-8995; webpage: http://chemgroups.ucdavis.edu/~chen/home.htm
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Affiliation(s)
- Harshal A Chokhawala
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, USA
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Yu H, Chokhawala HA, Varki A, Chen X. Efficient chemoenzymatic synthesis of biotinylated human serum albumin-sialoglycoside conjugates containing O-acetylated sialic acids. Org Biomol Chem 2007; 5:2458-63. [PMID: 17637967 PMCID: PMC2769491 DOI: 10.1039/b706507h] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sialyl Tn (STn) and sialyl lactoside derivatives containing O-acetylated sialic acid residues have been chemoenzymatically synthesized using a one-pot three-enzyme system and conjugated to biotinylated human serum albumin (HSA) using an adipic acid para-nitrophenyl ester coupling reagent. This approach provides an efficient and general protocol for preparing carbohydrate-protein conjugates containing base-sensitive groups.
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Affiliation(s)
- Hai Yu
- Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA. Fax: 01 530 752 8995; Tel: 01 530 754 6037; E-mail:
| | - Harshal A. Chokhawala
- Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA. Fax: 01 530 752 8995; Tel: 01 530 754 6037; E-mail:
| | - Ajit Varki
- Departments of Medicine and Cellular & Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Xi Chen
- Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA. Fax: 01 530 752 8995; Tel: 01 530 754 6037; E-mail:
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Huang S, Yu H, Chen X. Disaccharides as sialic acid aldolase substrates: synthesis of disaccharides containing a sialic acid at the reducing end. Angew Chem Int Ed Engl 2007; 46:2249-53. [PMID: 17309109 DOI: 10.1002/anie.200604799] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Shengshu Huang
- Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA
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Affiliation(s)
- Zhangyong Hong
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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Chokhawala HA, Yu H, Chen X. High-throughput substrate specificity studies of sialidases by using chemoenzymatically synthesized sialoside libraries. Chembiochem 2007; 8:194-201. [PMID: 17195254 PMCID: PMC2610223 DOI: 10.1002/cbic.200600410] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Indexed: 11/06/2022]
Abstract
Sialidases, or neuraminidases, are enzymes that cleave terminal sialic acid (Sia) residues from complex sialic acid-containing structures. They have been found in many animals and microorganisms and are important in various physiological and pathological processes. In order to understand the biological significance of diverse sialidases, it is important to study in detail the structural determinants of their natural substrates. Here, we report the synthesis of sialoside libraries containing para-nitrophenol-tagged sialosides with different naturally occurring sialic acid forms, different sialyl linkages, and different penultimate monosaccharides using a highly efficient one-pot three-enzyme chemoenzymatic approach. By using these compounds in a 96-well plate-based colorimetric high-throughput screening platform, the diversity of substrate preference is shown for seven bacterial sialidases. The sialoside libraries and the screening method are convenient tools for unravelling the substrate specificity and the biological function of sialidases.
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Affiliation(s)
- Harshal A. Chokhawala
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, Fax: (+1) 530-752-8995
| | - Hai Yu
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, Fax: (+1) 530-752-8995
| | - Xi Chen
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, Fax: (+1) 530-752-8995
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Abstract
PEP and aldolase mimicry is the key for a direct organocatalytic entry to precursors of ulosonic acids, biomolecules of enormous importance in biology, chemistry and medicine; in the key aldol reaction the dimethylacetal of pyruvic aldehyde is used as phosphoenolpyruvate (PEP) equivalent and the amino acid proline functions as an organocatalyst, imitating the enzyme.
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Affiliation(s)
- Dieter Enders
- Institut für Organische Chemie, RWTH Aachen, Landoltweg 1, Aachen, 52074, Germany.
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Abstract
Two isomeric 4-methylumbelliferyl-alpha-D-N-acetylneuraminylgalactopyranosides (1 and 2) were synthesised. These compounds contain either the natural alpha-2,3 or alpha-2,6 sialyl-galactosyl linkages, as well as an attached 4-methylumbelliferone for convenient detection of their hydrolyses. These compounds were designed as natural sialoside analogues to be used in a continuous assay of sialidase activity, where the sialidase-catalysed reaction is coupled with an exo-beta-galactosidase-catalysed hydrolysis of the released galactoside to give free 4-methylumbelliferone. The kinetic parameters for 1 and 2 were measured using the wild-type and nucleophilic mutant Y370G recombinant sialidase from Micromonospora viridifaciens. Kinetic parameters for these analogues measured using the new continuous assay were in good agreement with the parameters for the natural substrate, 3'-sialyl lactose. Given the selection of commercially available exo-beta-galactosidases that possess a variety of pH optima, this new method was used to characterise the full pH profile of the wild-type sialidase with the natural sialoside analogue 1. Thus, use of these new substrates 1 and 2 in a continuous assay mode, which can be detected by UV/Vis or fluorescence spectroscopy, makes characterisation of sialidase activity with natural sialoside linkages much more facile.
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Affiliation(s)
- Deepani Indurugalla
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada V5A 1S6
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Li J, Zheng M, Tang W, He PL, Zhu W, Li T, Zuo JP, Liu H, Jiang H. Syntheses of triazole-modified zanamivir analogues via click chemistry and anti-AIV activities. Bioorg Med Chem Lett 2006; 16:5009-13. [PMID: 16876409 DOI: 10.1016/j.bmcl.2006.07.047] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Revised: 06/05/2006] [Accepted: 07/17/2006] [Indexed: 10/24/2022]
Abstract
Sixteen novel 4-triazole-modified zanamivir (1) analogues were synthesized using the click reactions, and their inhibitory activities against avian influenza virus (AIV, H5N1) were determined. Compound 3b exerts promising inhibitory activity with EC(50) of 6.4 microM, which is very close to that of zanamivir (EC(50) = 2.8 microM). Molecular modeling provided the information about the binding model between inhibitors and neuraminidase, which are in good agreement with inhibitory activities.
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Affiliation(s)
- Jian Li
- Drug Discovery and Design Centre, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 201203, China
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Kajihara Y, Yoshihara A, Hirano K, Yamamoto N. Convenient synthesis of a sialylglycopeptide-thioester having an intact and homogeneous complex-type disialyl-oligosaccharide. Carbohydr Res 2006; 341:1333-40. [PMID: 16701588 DOI: 10.1016/j.carres.2006.04.037] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2006] [Revised: 04/10/2006] [Accepted: 04/17/2006] [Indexed: 11/22/2022]
Abstract
Access to glycopeptides with C-terminal thioester functionality is essential for the synthesis of large glycopeptides and glycoproteins through the use of native chemical ligation. Toward that end, we have developed a concise method for the synthesis of a glycopeptide thioester having an intact complex-type dibranched disialyl-oligosaccharide. The synthesis employed a coupling reaction between benzylthiol and a free carboxylic acid at the C-terminus of a glycopeptide in which the peptide side chains are protected. After construction of glycopeptide on the HMPB-PEGA resin through the Fmoc-strategy, the protected glycopeptide was released upon treatment with acetic acid/trifluoroethanol and then the C-terminal carboxylic acid was coupled with benzylthiol at -20 degrees C in DMF. For this coupling, PyBOP/DIPEA was found to be the best for the formation of the thioester, while avoiding racemization. Finally, the protecting groups were removed in good yield with 95% TFA, thus affording a glycopeptide-thioester having an intact and homogeneous complex-type disialyl-oligosaccharide.
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Affiliation(s)
- Yasuhiro Kajihara
- International Graduate School of Arts and Sciences, Yokohama City University, 22-2, Seto, Yokohama 236-0027, Japan.
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18
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Abstract
An efficient and elegant synthesis of alpha(2,8)-oligosialosides is described. The 5-N,4-O-carbonyl-protected sialyl donor undergoes alpha-sialylation in CH2Cl2 to give alpha(2,8)- and alpha(2,9)-disialosides in excellent yields. The 5-N,4-O-carbonyl protecting group was effective in improving the reactivity of the C8 hydroxyl groups toward glycosylation. Using the sialyl building block, the synthesis of tetra-alpha(2,8)-sialic acid was accomplished by using a simple glycosidation and deprotection protocol.
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Affiliation(s)
- Hiroshi Tanaka
- Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology 2-12-1-S1-35, Oookayama, Meguro, Tokyo 152-8552, Japan.
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19
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Florian C, Foltz J, Norreel JC, Rougon G, Roullet P. Post-training intrahippocampal injection of synthetic poly-alpha-2,8-sialic acid-neural cell adhesion molecule mimetic peptide improves spatial long-term performance in mice. Learn Mem 2006; 13:335-41. [PMID: 16705136 PMCID: PMC1475815 DOI: 10.1101/lm.187506] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2005] [Accepted: 02/07/2006] [Indexed: 11/25/2022]
Abstract
Several data have shown that the neural cell adhesion molecule (NCAM) is necessary for long-term memory formation and might play a role in the structural reorganization of synapses. The NCAM, encoded by a single gene, is represented by several isoforms that differ with regard to their content of alpha-2,8-linked sialic acid residues (PSA) on their extracellular domain. The carbohydrate PSA is known to promote plasticity, and PSA-NCAM isoforms remain expressed in the CA3 region of the adult hippocampus. In the present study, we investigated the effect on spatial memory consolidation of a PSA gain of function by injecting a PSA mimetic peptide (termed pr2) into the dorsal hippocampus. Mice were subjected to massed training in the spatial version of the water maze. Five hours after the last training session, experimental mice received an injection of pr2, whereas control mice received PBS or reverse peptide injections in the hippocampal CA3 region. Memory retention was tested at different time intervals: 24 h, 1 wk, and 4 wk. The results showed that the post-training infusion of pr2 peptide significantly increases spatial performance whenever it was assessed after the training phase. By contrast, administration of the control reverse peptide did not affect retention performance. These findings provide evidence that (1) PSA-NCAM is involved in memory consolidation processes in the CA3 hippocampal region, and (2) PSA mimetic peptides can facilitate the formation of long-term spatial memory when injected during the memory consolidation phase.
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Affiliation(s)
- Cédrick Florian
- Centre de Recherches sur la Cognition Animale, CNRS 5169, Université Paul Sabatier, 31062 Toulouse, France
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20
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21
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Lu CP, Ren CT, Lai YN, Wu SH, Wang WM, Chen JY, Lo LC. Design of a Mechanism-Based Probe for Neuraminidase To Capture Influenza Viruses. Angew Chem Int Ed Engl 2005; 44:6888-92. [PMID: 16215975 DOI: 10.1002/anie.200501738] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Chun-Ping Lu
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
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22
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Abstract
We report the synthesis of a novel alkyl polysulfated sialic acid derivative denoted as NMSO3. NMSO3 exhibited potent inhibition against both laboratory and clinical human immunodeficiency virus type 1 (HIV-1). The anti-viral activity of this compound (1 uM) was compared to dextran sulfate (3 uM), and was found to be more potent against HIV-1IIIb than AZT (10 uM). The anti-coagulation time was more than 15-fold shorter than that of dextran sulfate. An in vivo anti-viral study of NMSO3 in NOD-SCID-PBL mice HIV model showed complete protection of the animals from virus challenge at the concentration of 10 mg/kg. This suggests that NMSO3 can be effective in the treatment of HIV-infected individuals.
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Affiliation(s)
- Masaki Terada
- Central Research Institute, Nissin Food Products Co. Ltd., 2247 Noji-cho, Kusatsu-city, Shiga 525-0055, Japan.
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23
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Abstract
[reaction: see text] A new method for the synthesis of alpha(2 --> 9) oligosialic acids is developed using phosphite sialyl donors that are protected with a C-5 N-trifluoroacetyl (NHTFA) substituent. Compared with conventional donors, these donors gave a higher degree of alpha-anomeric selectivity during glycosidic bond formation and better yields during iterative sialylation in the synthesis of oligosialic acids.
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Affiliation(s)
- Chang-Ching Lin
- Institute of Chemistry and Genomic Research Center, Academia Sinica, Taipei, Taiwan
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24
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Hinou H, Kurogochi M, Shimizu H, Nishimura SI. Characterization of Vibrio cholerae Neuraminidase by a Novel Mechanism-Based Fluorescent Labeling Reagent. Biochemistry 2005; 44:11669-75. [PMID: 16128567 DOI: 10.1021/bi0509954] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Vibrio cholerae neuraminidase (VCNA) plays a significant role in the pathogenesis of cholera by removing sialic acid residues from higher-order gangliosides to an unmasked GM1, the essential receptor for cholera toxin. Here we report that a novel mechanism-based fluorescent labeling reagent, 5-acetamido-2-(4-N-5-dimethylaminonaphthalene-1-sulfonyl-2-difluoromethylphenyl)-3,5-dideoxy-d-glycero-alpha-d-galacto-2-nonulopyranosonic acid (1), becomes a unique irreversible inhibitor of VCNA. Characterization of an inactivated VCNA by MALDI-TOF/TOFMS analysis revealed that the Asp-576 and Arg-577 residues, which are located within the (576)DRFF(579) sequence, were specifically labeled with this suicide-type fluorescent substrate. Neither Asp-576 nor Arg-577 has ever been known to contribute to a specific residue in the rigid and highly conserved active site of VCNA investigated by crystallographic analysis, suggesting that a flexible beta-turn structure containing this sequence may have a crucial role in the dynamic nature of substrate recognition and catalytic action by VCNA.
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Affiliation(s)
- Hiroshi Hinou
- Glycochemosynthesis Team, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo 062-8517, Japan
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25
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Liu KG, Yan S, Wu YL, Yao ZJ. Synthesis of 4-azido-4-deoxy-Neu5,7,8,9Ac42en1Me. A key intermediate for the synthesis of GG167 from D-glucono-delta-lactone. Org Lett 2005; 6:2269-72. [PMID: 15200337 DOI: 10.1021/ol0491890] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] Stereoselective synthesis of 5-acetamido-7,8,9-tri-O-acetyl-2,6-anhydro-4-azido-3,4,5-trideoxy-D-glycero-D-galacto-non-2-enonic acid methyl ester, an advanced key intermediate for the synthesis of neuraminidase inhibitor GG167 (Zanamivir, Relenza), was accomplished using D-glucono-delta-lactone as starting material. A highly diastereoselective allyllation of an imine intermediate, a regioselective azide-opening of an aziridine, and chemoselective oxidations of vicinal diols served successfully as key steps.
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Affiliation(s)
- Ke-Gang Liu
- State Key Laboratory of Bioorganic and Natural Product Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, China
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26
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Macdonald SJF, Cameron R, Demaine DA, Fenton RJ, Foster G, Gower D, Hamblin JN, Hamilton S, Hart GJ, Hill AP, Inglis GGA, Jin B, Jones HT, McConnell DB, McKimm-Breschkin J, Mills G, Nguyen V, Owens IJ, Parry N, Shanahan SE, Smith D, Watson KG, Wu WY, Tucker SP. Dimeric Zanamivir Conjugates with Various Linking Groups Are Potent, Long-Lasting Inhibitors of Influenza Neuraminidase Including H5N1 Avian Influenza. J Med Chem 2005; 48:2964-71. [PMID: 15828835 DOI: 10.1021/jm040891b] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The synthesis, antiviral and pharmacokinetic properties of zanamivir (ZMV) dimers 8 and 13 are described. The compounds are highly potent neuraminidase (NA) inhibitors which, along with dimer 3, are being investigated as potential second generation inhaled therapies both for the treatment of influenza and for prophylactic use. They show outstanding activity in a 1 week mouse influenza prophylaxis assay, and compared with ZMV, high concentrations of 8 and 13 are found in rat lung tissue after 1 week. Retention of compounds in rat lung tissue correlated both with molecular weight (excluding 3 and 15) and with a capacity factor K' derived from immobilized artificial membrane (IAM) chromatography (including 3 and 15). Pharmacokinetic parameters for 3, 8 and 13 in rats show the compounds have short to moderate plasma half-lives, low clearances and low volumes of distribution. Dimer 3 shows NA inhibitory activity against N1 viruses including the recent highly pathogenic H5N1 A/Chicken/Vietnam/8/2004. In plaque reduction assays, 3, 8 and 13 show good to outstanding potency against a panel of nine flu A and B virus strains. Consistent with its shorter and more rigid linking group, dimer 8 has been successfully crystallized.
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Affiliation(s)
- Simon J F Macdonald
- GlaxoSmithKline Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, United Kingdom.
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27
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Affiliation(s)
- Sarah J Luchansky
- Department of Chemistry, University of California - Berkeley, B84 Hildebrand Hall, Berkeley, CA 94720, USA
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28
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Pal S, Ghosh S, Mandal C, Kohla G, Brossmer R, Isecke R, Merling A, Schauer R, Schwartz-Albiez R, Bhattacharya DK, Mandal C. Purification and characterization of 9-O-acetylated sialoglycoproteins from leukemic cells and their potential as immunological tool for monitoring childhood acute lymphoblastic leukemia. Glycobiology 2004; 14:859-70. [PMID: 15190007 DOI: 10.1093/glycob/cwh111] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Sialic acids as terminal residues of oligosaccharide chains play crucial roles in several cellular recognition events. Exploiting the selective affinity of Achatinin-H toward N-acetyl-9-O-acetylneuraminic acid-alpha2-6-GalNAc, we have demonstrated the presence of 9-O-acetylated sialoglycoproteins (Neu5,9Ac(2)-GPs) on lymphoblasts of 70 children with acute lymphoblastic leukemia (ALL) and on leukemic cell lines by fluorimetric HPLC and flow cytometric analysis. This study aims to assess the structural aspect of the glycotope of Neu5,9Ac(2)-GPs(ALL) and to evaluate whether these disease-specific molecules can be used to monitor the clinical outcome of ALL. The Neu5,9Ac(2)-GPs(ALL) were affinity-purified, and three distinct leukemia-specific molecular determinants (135, 120, and 90 kDa) were demonstrated by SDS-PAGE, western blotting, and isoelectric focusing. The carbohydrate epitope of Neu5,9Ac(2)-GPs(ALL) was confirmed by using synthetic sialic acid analogs. The enhanced presence of anti-Neu5,9Ac(2)-GP(ALL) antibody in ALL patients prompted us to develop an antigen-ELISA using purified Neu5,9Ac(2)-GPs(ALL) as coating antigens. Purified antigen was able to detect leukemia-specific antibodies at presentation of disease, which gradually decreased with treatment. Longitudinal monitoring of 18 patients revealed that in the early phase of the treatment patients with lower anti-Neu5,9Ac(2)-GPs showed a better prognosis. Minimal cross-reactivity was observed in other hematological disorders (n = 50) like chronic myeloid leukemia, acute myelogenous leukemia, chronic lymphocytic leukemia, and non-Hodgkin's lymphoma as well as normal healthy individuals (n = 21). This study demonstrated the potential of purified Neu5,9Ac(2)-GPs(ALL) as an alternate tool for detection of anti-Neu5,9Ac(2)-GP antibodies to be helpful for diagnosis and monitoring of childhood ALL patients.
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Affiliation(s)
- Santanu Pal
- Immunobiology Division, Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700032, India
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29
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Ikeda K, Kitani S, Sato K, Suzuki T, Hosokawa C, Suzuki Y, Tanaka K, Sato M. 2β,3β-Difluorosialic acid derivatives structurally modified at the C-4 position: synthesis and biological evaluation as inhibitors of human parainfluenza virus type 1. Carbohydr Res 2004; 339:1367-72. [PMID: 15113676 DOI: 10.1016/j.carres.2004.02.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2003] [Accepted: 02/18/2004] [Indexed: 10/26/2022]
Abstract
A series of 4-O-substituted 2beta,3beta-difluorosialic acid derivatives (3a-d) has been synthesized. A key intermediate was synthesized efficiently by the electrophilic syn-addition of fluorine to the double bond of a glycal precursor using molecular fluorine or xenon difluoride in the presence of BF(3).OEt(2). Among compounds 3a-d, the 4-O-thiocarbamoylmethyl derivative 3c showed the most potent inhibitory activity against sialidase of human parainfluenza virus type 1. [structure: see text].
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Affiliation(s)
- Kiyoshi Ikeda
- Department of Organic Chemistry, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan.
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30
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Kalovidouris SA, Blixt O, Nelson A, Vidal S, Turnbull WB, Paulson JC, Stoddart JF. Chemically defined sialoside scaffolds for investigation of multivalent interactions with sialic acid binding proteins. J Org Chem 2004; 68:8485-93. [PMID: 14575475 DOI: 10.1021/jo030203g] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Four glycodendrons and a glycocluster were synthesized from carbohydrate building blocks to form paucivalent (di- to tetravalent) structures of controlled scaffold architectures. Enzymatic sialylation of the functionalized cluster and dendrons, terminated in lactose residues, generated a library of paucivalent synthetic sialosides displaying sialic acids with different dispositions. These newly constructed bioactive sialic acid-based structures were differentially recognized by sialoadhesin, a mammalian macrophage sialic acid binding protein. The binding of the sialosides to sialoadhesin was evaluated by an enzyme-linked immunosorbant assay to investigate the complementarity of scaffold structure and binding to sialoadhesin. Modulating the interaction between sialoadhesin and its sialic acid ligands has important implications in immunobiology.
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Affiliation(s)
- Stacey A Kalovidouris
- California NanoSystems Institute and the Department of Chemistry and Biochemistry, University of California, Los Angeles, 405 Hilgard Avenue, Los Angeles, California 90095, USA
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31
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Abstract
Formal total syntheses of the naturally occurring deaminated sialic acids KDN (2), a potential oncofetal antigen, and N-acetylneuraminic acid (Neu5Ac, 1), the most naturally abundant sialic acid, have been accomplished in 46% and 9.3% overall yield, respectively, via a novel ketalization/ring-closing metathesis sequence. The rapid introduction of all oxygen and nitrogen functionality in a completely stereocontrolled manner exploited a rigid 6,8-dioxabicyclo[3.2.1]oct-2-ene template. The 2,7-anhydro-KDN derivative 40 served as an advanced intermediate in each of the two syntheses.
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Affiliation(s)
- Eric A Voight
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706-1396, USA
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32
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Machinami T, Itaba Y, Kayama A, Fujimoto T, Suami T. Oxidation of 3-C-(2-amino-2-deoxy-D-glucopyranosyl)-1-propene compounds and the structure of 3-C-(2-amino-2-deoxy-D-glucopyranosyl)-1,2-propanediol derivatives for a synthesis of 2,3-didehydro-2,7-dideoxy-N-acetylneuraminic acid. Carbohydr Res 2002; 337:1917-27. [PMID: 12433457 DOI: 10.1016/s0008-6215(02)00225-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Oxidation of 5-acetamido-4,8-anhydro-1,2,3,5-tetradeoxy-D-glycero-D-ido-non-1-enitol [3-C-(2-amino-2-deoxy-beta-D-glucopyranosyl)-1-propene] was studied to search for preparative routes to aminodeoxy didehydro nonulosonic acid derivatives. Since only moderate chiral induction was observed with osmium tetroxide dihydroxylation as well as with peracid epoxidation, the catalytic asymmetric dihydroxylation conditions were applied to give the stereocontrolled formation of 1,2-propanediol derivatives. The structures of these diastereoisomeric 1,2-propanediol derivatives were determined by X-ray crystallographic analyses. The formation of diastereoisomeric 1,2-propanediols also varied with the nature of 2-substituent on the aminodoexy glycosyl moiety. Thus 5-acetamido-4,8-anhydro-3,5-dideoxy-D-erythro-L-ido-nonitol [(2S)-3-C-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-1,2-propanediol] was obtained predominantly up to 70% from 3-C-(2-acetamido-2-deoxyglycosyl)-1-propene by the use of ADmixbeta reagent. The (2S)-propanediol derivative was transformed in a five-step reaction sequence to 2,3-didehydro-2,7-dideoxy-N-acetylneuraminic acid.
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Affiliation(s)
- Tomoya Machinami
- Department of Chemistry, College of Science and Technology, Meisei University, Hino, Tokyo 191-8506, Japan.
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33
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Landers JJ, Cao Z, Lee I, Piehler LT, Myc PP, Myc A, Hamouda T, Galecki AT, Baker JR. Prevention of influenza pneumonitis by sialic Acid-conjugated dendritic polymers. J Infect Dis 2002; 186:1222-30. [PMID: 12402191 DOI: 10.1086/344316] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2002] [Revised: 07/08/2002] [Indexed: 11/03/2022] Open
Abstract
Influenza A viral infection begins by hemagglutinin glycoproteins on the viral envelope binding to cell membrane sialic acid (SA). Free SA monomers cannot block hemagglutinin adhesion in vivo because of toxicity. Polyvalent, generation 4 (G4) SA-conjugated polyamidoamine (PAMAM) dendrimer (G4-SA) was evaluated as a means of preventing adhesion of 3 influenza A subtypes (H1N1, H2N2, and H3N2). In hemagglutination-inhibition assays, G4-SA was found to inhibit all H3N2 and 3 of 5 H1N1 influenza subtype strains at concentrations 32-170 times lower than those of SA monomers. In contrast, G4-SA had no ability to inhibit hemagglutination with H2N2 subtypes or 2 of 5 H1N1 subtype strains. In vivo experiments showed that G4-SA completely prevented infection by a H3N2 subtype in a murine influenza pneumonitis model but was not effective in preventing pneumonitis caused by an H2N2 subtype. Polyvalent binding inhibitors have potential as antiviral therapeutics, but issues related to strain specificity must be resolved.
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Affiliation(s)
- Jeffrey J Landers
- Center for Biologic Nanotechnology, Department of Internal Medicine, Division of Allergy, University of Michigan, Ann Arbor, Michigan 48109, USA.
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34
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Abstract
The preparation of a disaccharide 2, Neu5Ac-alpha-(2-->5)Neu5Gc having a alpha-benzyl protecting group at the reducing end, by the coupling of the easily accessible building units 4 and 5 is described. Subsequent deprotection of the coupling adduct led to the isolation of the target compound 2 in high yield.
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Affiliation(s)
- Chien-Tai Ren
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
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35
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Affiliation(s)
- Milton J Kiefel
- Centre for Biomolecular Science and Drug Discovery, Griffith University, Gold Coast Campus, PMB 50 Gold Coast Mail Centre, Queensland 9726, Australia
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36
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Tsvetkov YE, Shashkov AS, Knirel YA, Zähringer U. Synthesis and NMR spectroscopy of nine stereoisomeric 5,7-diacetamido-3,5,7,9-tetradeoxynon-2-ulosonic acids. Carbohydr Res 2001; 335:221-43. [PMID: 11595217 DOI: 10.1016/s0008-6215(01)00235-x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Derivatives of 5,7-diamino-3,5,7,9-tetradeoxynon-2-ulosonic acids are essential constituents of some bacterial polysaccharides and glycoproteins. In order to establish reliably the configuration of the natural sugars, nine stereoisomeric 5,7-diacetamido-3,5,7,9-tetradeoxynon-2-ulosonic acids were synthesized, including di-N-acetyl-legionaminic and -pseudaminic acids (the D-glycero-D-galacto and L-glycero-L-manno isomers, respectively) and their isomers at C-4, C-5, C-7, and C-8 having the L-glycero-D-galacto, D-glycero-D-talo, L-glycero-D-talo, D-glycero-L-altro, L-glycero-L-altro, D-glycero-L-manno, and L-glycero-L-gluco configurations. Synthesis was performed by condensation of 2,4-diacetamido-2,4,6-trideoxy-L-gulose, -D-mannose, -D-talose, and -L-allose with oxalacetic acid under basic conditions, the reaction of the last two precursors being accompanied by epimerisation at C-2. The 1H and 13C NMR data of the synthetic compounds are discussed. Acetylated methyl esters of the C-7 and C-8 isomeric nonulosonic acids were prepared and used for analysis of the side-chain conformation by NMR spectroscopy.
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Affiliation(s)
- Y E Tsvetkov
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospeckt 47, 119991 Moscow, Russian Federation.
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37
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Abstract
A novel method for synthesizing CMP-NeuAc was established. We first confirmed that the putative neuA gene of Haemophilus influenzae, identified by its whole genome sequence project, indeed encodes CMP-NeuAc synthetase (EC 2.7.7.43). The enzyme requires CTP as a cytidylyl donor for cytidylylation of NeuAc. The enzyme was coupled with an enzymatic CTP-generating system from CMP and inorganic polyphosphate as a sole phospho-donor driven by the combination of polyphosphate kinase and CMP kinase, where phosphorylation of CMP is done by the combined activity expressed by both enzymes, and subsequent phosphorylation of CDP by polyphosphate kinase itself occurred efficiently. When CMP-NeuAc synthetase of H. influenzae, polyphosphate kinase, and CMP kinase were added to the reaction mixture containing equimolar concentrations (15 mM) of CMP and NeuAc, and polyphosphate (150 mM in terms of phosphate), CMP-NeuAc was synthesized up to 10 mM in 67% yield.
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Affiliation(s)
- K Ishige
- Biochemicals Division, YAMASA Corporation, Choshi, Chiba, Japan.
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38
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Tsvetkov YE, Shashkov AS, Knirel YA, Zähringer U. Synthesis and identification in bacterial lipopolysaccharides of 5,7-diacetamido-3,5,7,9-tetradeoxy-D-glycero-D-galacto- and -D-glycero-D-talo-non-2-ulosonic acids. Carbohydr Res 2001; 331:233-7. [PMID: 11383892 DOI: 10.1016/s0008-6215(01)00041-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
5,7-Diacetamido-3,5,7,9-tetradeoxy-D-glycero-D-galacto- and -D-glycero-D-talo-non-2-ulosonic acids were synthesized by condensation of 2,4-diacetamido-2,4,6-trideoxy-D-mannose with oxalacetic acid. Comparison of the 1H and 13C NMR data and the specific optical rotation values of these monosaccharides and the corresponding L-glycero-D-galacto and L-glycero-D-talo isomers synthesized earlier [Tsvetkov, Y. E.; Shashkov, A. S.; Knirel, Y. A.; Backinowsky, L. V.; Zähringer, U. Mendeleev Commun. 2000, 90-92] with data of the natural compounds enabled the identification in bacterial lipopolysaccharides of derivatives of 5,7-diamino-3,5,7,9-tetradeoxy-D-glycero-D-galacto-non-2-ulosonic (legionaminic) acid and epimers of legionaminic acid at C-4 and C-8.
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Affiliation(s)
- Y E Tsvetkov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
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39
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Abstract
The influenza virus neuraminidase (NA) is an enzyme essential for viral infection and offers a potential target for antiviral drug development. We aimed our research at the synthesis of non-carbohydrate molecules able to inhibit NA as transition-state analogues. Aromatic sialic acid analogues (compound 5 and compound 10) were synthesised in good yields starting from commercially available benzoic acids using a suitable synthetic strategy.
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Affiliation(s)
- A Bianco
- Dipartimento di Chimica, Università La Sapienza, Rome, Italy.
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40
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Abstract
alpha-2,3-Sialyltransferase catalyzes the transfer of sialic acid from CMP-sialic acid (1) to a lactose acceptor. An analogue of 1 was synthesized in which the anomeric oxygen atom was replaced with a sulfur atom (1S). The key step in the synthesis of 1S was a tetrazole-promoted coupling of a cytidine-5'-phosphoramidite with a glycosyl thiol of a protected sialic acid. Compounds 1 and 1S were characterized for their activity in a sialyl transfer assay. The rate of solvolysis in aqueous buffer of analogue 1S was 50-fold slower than that of 1. Analogue 1S was found to be substrate for alpha-2,3-sialyltransferase. The K(m) of 1S was just 3-fold higher than that of 1, while the k(cat) of 1S was 2 orders of magnitude lower compared to 1.
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Affiliation(s)
- S B Cohen
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA
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41
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Ikeuchi Y, Sumiya M, Kawamoto T, Akimoto N, Mikata Y, Kishigami M, Yano S, Sasaki T, Yoneda F. Synthesis and antitumor activities of novel 5-deazaflavin-sialic acid conjugate molecules. Bioorg Med Chem 2000; 8:2027-35. [PMID: 11003147 DOI: 10.1016/s0968-0896(00)00124-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
6-Nitro-5-deazaflavin derivatives bearing O-(methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-alpha- and beta-D-galacto-non-2-ulopyranosylonate)alkyl group (sialosylalkyl group) at N(3) or N(10) and 8-amino-5-deazaflavin substituted with the sialosylalkyl group at the amino group were synthesized and their physicochemical properties as well as antitumor effects on KB and L1210 cells have been investigated. The configurations of the glycosides were determined by 1H NMR and rate of hydrolysis of the glycosidic bond. It has been found that these conjugate molecules show significant antitumor activities. Combination of an 8-amino-5-deazaflavin with the sialosylalkyl group have been found to give rise to significant increase in antitumor activities of the compound. Antitumor effects of 6-nitro-5-deazaflavin-sialic acid conjugate molecules were similar or rather weak in comparison with those of the 6-nitro-5-deazaflavin derivatives without sialosylalkyl group.
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Affiliation(s)
- Y Ikeuchi
- Faculty of Pharmaceutical Sciences, Kyoto University, Japan.
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42
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Washiya K, Furuike T, Nakajima F, Lee YC, Nishimura SI. Design of fluorogenic substrates for continuous assay of sialyltransferase by resonance energy transfer. Anal Biochem 2000; 283:39-48. [PMID: 10929806 DOI: 10.1006/abio.2000.4632] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glycosyltransferases are important synthetic enzymes for the construction of naturally occurring glycoconjugates as well as for the design of neoglycoconjugates. The assay methods currently available for these enzymes require tedious and time-consuming procedures for separation of products and do not permit continual assay of enzyme activities. As a set of convenient fluorogenic substrates for continuous monitoring of sialyltransferase activities, we designed and synthesized a novel CMP-Neu5Ac derivative with a naphthylmethyl group at the C-9 position and N-acetyllactosamine derivative containing a dansyl group at the terminal position of aglycon. In such substrates, the emission peak of the naphthylmethyl group (lambdaem = 340 nm) of the glycosyl donor is successfully overlapped with the excitation peak due to the dansyl group (lambdaex = 335 nm) of the glycosyl acceptor. A coupling reaction of these two substrates catalyzed by rat liver 2,6-sialyltransferase caused an increase of dansyl fluorescence (lambdaem = 525 nm) and a decrease of naphthylmethyl fluorescence on the basis of resonance energy transfer between two fluorescence probes. The substrates presented here permit continuous fluorescent monitoring of enzymatic sugar combining reactions. Actually, using this time course of enzymatic reactions, kinetic constants of rat liver 2,6-sialyltransferase against glycosyl donor substrates were estimated to be Km = 4.85 microM and Vmax. = 0.119 micromol/min, respectively. This strategy allows precise and efficient analyses of enzyme kinetics not possible with the conventional assay methods for the glycosyltransferases that usually require separation of products from the reaction mixture.
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Affiliation(s)
- K Washiya
- Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo, Japan
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43
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Abstract
[reaction: see text] The synthesis of a six-carbon truncated sialic acid is described. A key step in the synthesis was an indium-mediated allyl addition to a serine-derived aldehyde. Careful choice of protecting groups was found to be necessary in order to prevent unwanted side reactions throughout the sequence. The truncated sialic acid was obtained in a form suitable for activation as a glycosyl donor.
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Affiliation(s)
- M D Chappell
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA
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44
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Yang J, Schenkman S, Horenstein BA. Primary 13C and beta-secondary 2H KIEs for trans-sialidase. A snapshot of nucleophilic participation during catalysis. Biochemistry 2000; 39:5902-10. [PMID: 10801342 DOI: 10.1021/bi000061+] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Trypanosoma cruzi trans-sialidase catalyzes a novel reaction that involves the transfer of sialic acid between host and parasite glycoconjugates. In this paper, we report kinetic isotope effect studies on recombinant trans-sialidase. beta-Dideuterium and primary 13C isotope effects were measured for a good substrate, sialyl-lactose, and a slow substrate, sialyl-galactose, in both acid-catalyzed solvolysis and enzymatic transfer reactions. The beta-dideuterium isotope effect for sialyl-lactose in the acid hydrolysis reaction was 1.113 +/- 0.012. The primary 13C isotope effects for hydrolysis of sialyl-lactose and sialyl-galactose were 1. 016 +/- 0.011 and 1.015 +/- 0.008, respectively. In the enzymatic transfer reactions, the beta-dideuterium and primary 13C effects for sialyl-galactose were 1.060 +/- 0.008 and 1.032 +/- 0.008, respectively. The isotope effects for hydrolysis describe a dissociative SN1-like mechanism, and these data are contrasted by the data for the enzyme-catalyzed reaction. The enzymatic deuterium isotope effects are lower by a factor of 2, but the primary carbon isotope effects are higher by a factor of 2. This pattern describes a mechanism involving nucleophilic participation in the rate-determining transition state.
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Affiliation(s)
- J Yang
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, USA
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45
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Abstract
A multiple sialic acid-bearing polymer 7 has been made in which a novel 4-N-substituted sialoside 5 has been coupled to polyacrylamide. The conjugate 7 has been found to inhibit the agglutination of influenza virus to red blood cells with HAI inhibition constants of around 10(-6) M, based on the sialic acid concentration.
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Affiliation(s)
- W Y Wu
- Chemistry Department, Monash University, Clayton, Victoria, Australia
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46
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Abstract
A practical synthesis of Kdn2en and 4-amino-4-deoxy-Kdn2en has been achieved via a key intermediate, methyl 4,5,7,8,9-penta-O-acetyl-2,6-anhydro-3-deoxy-D-glycero-D-galacto-non-2- enonate, which has been prepared from Kdn in three steps in 91% overall yield.
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Affiliation(s)
- X L Sun
- School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan
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47
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Andrews DM, Cherry PC, Humber DC, Jones PS, Keeling SP, Martin PF, Shaw CD, Swanson S. Synthesis and influenza virus sialidase inhibitory activity of analogues of 4-Guanidino-Neu5Ac2en (Zanamivir) modified in the glycerol side-chain. Eur J Med Chem 1999; 34:563-74. [PMID: 11278042 DOI: 10.1016/s0223-5234(00)80026-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Analogues of 4-Guanidino-Neu5Ac2en (Zanamivir) have been prepared containing carbamate substituents at the 7-hydroxy position. (4S,5R,6R)-5-Acetylamino-6-[1R-[(6-aminohexyl)carbamoyloxy]-2R,3-dihydroxypropyl]-4-guanidino-5,6-dihydro-4H-pyran-2carboxylic acid and (4S,5R,6R)-5-Acetylamino-6-[1R-[heptylcarbamoyloxy]-2R,3-dihydroxypropyl]-4-guanidino-5,6-dihydro4H-pyran2-carboxylic acid were the two analogues possessing activity comparable to Zanamivir, showing potent inhibition of influenza virus sialidases and good antiviral activity in vitro.
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Affiliation(s)
- D M Andrews
- Department of Medicinal Chemistry, Glaxo-Wellcome Medicines Research Centre, Gunnels Wood Road, Herts, SG1 2NY, Stevenage, UK
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48
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Abstract
As part of our program to design, develop and prepare protective vaccines against the bacterial pathogens Group B Streptococcus, we report the synthesis of a disialylated hexasaccharide. This hexasaccharide represents a portion of the serotype-specific capsular polysaccharide of Type VIII that has the tetrasaccharide repeat unit [beta-L-Rhap-(1-->4)-beta-D-Glcp-(1-->4)-[alpha-Neu5Ac-(2--> 3)]-beta-D- Galp-(1-->4)]n. A tetrasaccharide corresponding to this repeat unit has been synthesized by us [E. Eichler, H.J. Jennings, D.M. Whitfield, J. Carbohydr. Chem., 16 (1997) 385-411]. Since the protective epitopes are believed to involve several repeat units, methods to extend this tetrasaccharide were examined. This objective requires a glycosylation of the unreactive OH-4 of the beta-L-Rhap, which was accomplished by coupling a D-Galp glycosyl trichloroacetimidate donor with a beta-L-Rhap-(1-->4)-D-Glcp acceptor. Subsequent coupling of this trisaccharide as a donor to an alpha-Neu5Ac-(2-->3)-D-Galp disaccharide acceptor gave a pentasaccharide. The pentasaccharide was deprotected and enzymatically sialylated using an alpha-(2-->3)-sialyltransferase from Campylobacter jejuni to give the title hexasaccahride alpha-Neu5Ac-(2-->3)- beta-D-Galp-(1-->4)-beta-L-Rhap-(1-->4)-beta-D-Glcp-(1-->4)-[alpha -Neu5Ac- (2-->3)]-beta-D-Galp-(1-->O)-(CH2)3N3.
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Affiliation(s)
- E Eichler
- National Research Council, Ottawa, Ontario, Canada
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49
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Reuter JD, Myc A, Hayes MM, Gan Z, Roy R, Qin D, Yin R, Piehler LT, Esfand R, Tomalia DA, Baker JR. Inhibition of viral adhesion and infection by sialic-acid-conjugated dendritic polymers. Bioconjug Chem 1999; 10:271-8. [PMID: 10077477 DOI: 10.1021/bc980099n] [Citation(s) in RCA: 212] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Multiple sialic acid (SA) residues conjugated to a linear polyacrylamide backbone are more effective than monomeric SA at inhibiting influenza-induced agglutination of red blood cells. However, "polymeric inhibitors" based on polyacrylamide backbones are cytotoxic. Dendritic polymers offer a nontoxic alternative to polyacrylamide and may provide a variety of potential synthetic inhibitors of influenza virus adhesion due to the wide range of available polymer structures. We evaluated several dendritic polymeric inhibitors, including spheroidal, linear, linear-dendron copolymers, comb-branched, and dendrigraft polymers, for the ability to inhibit virus hemagglutination (HA) and to block infection of mammalian cells in vitro. Four viruses were tested: influenza A H2N2 (selectively propagated two ways), X-31 influenza A H3N2, and sendai. The most potent of the linear and spheroidal inhibitors were 32-256-fold more effective than monomeric SA at inhibiting HA by the H2N2 influenza virus. Linear-dendron copolymers were 1025-8200-fold more effective against H2N2 influenza, X-31 influenza, and sendai viruses. The most effective were the comb-branched and dendrigraft inhibitors, which showed up to 50000-fold increased activity against these viruses. We were able to demonstrate significant (p < 0.001) dose-dependent reduction of influenza infection in mammalian cells by polymeric inhibitors, the first such demonstration for multivalent SA inhibitors. Effective dendrimer polymers were not cytotoxic to mammalian cells at therapeutic levels. Of additional interest, variation in the inhibitory effect was observed with different viruses, suggesting possible differences due to specific growth conditions of virus. SA-conjugated dendritic polymers may provide a new therapeutic modality for viruses that employ SA as their target receptor.
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Affiliation(s)
- J D Reuter
- Center for Biologic Nanotechnology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
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50
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Martin R, Witte KL, Wong CH. The synthesis and enzymatic incorporation of sialic acid derivatives for use as tools to study the structure, activity, and inhibition of glycoproteins and other glycoconjugates. Bioorg Med Chem 1998; 6:1283-92. [PMID: 9784869 DOI: 10.1016/s0968-0896(98)00121-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Methods have been developed for the enzymatic synthesis of complex carbohydrates and glycoproteins containing in the sialic acid moiety the heavy metal mercury or the transition-state analog phosphonate of the influenza C 9-O-acetyl-neuraminic acid esterase-catalyzed reaction. 5-Acetamido-3, 5-dideoxy-9-methylphosphono-beta-D-glycero-D-galacto-nonulopyra nosidonic acid (1), 5-acetamido-3,5-dideoxy-9-methylphosphono-2-propyl-alpha-D- glycero-D-galacto-nonulopyranosidonic acid triethylammonium salt (2), and 5-acetamido-9-thiomethylmercuric-3, 5,9-trideoxy-beta-D-glycero-D-galacto-nonulopyranosidonic acid (3) were synthesized. Compounds 1 and 2 are proposed transition state inhibitors of an esterase vital for the binding and infection of influenza C. Compound 3 was enzymatically incorporated into an oligosaccharide and a non-natural glycoprotein for use as an aid in the structure determination of these compounds by X-ray crystallography.
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Affiliation(s)
- R Martin
- Department of Chemistry, Scripps Research Institute, La Jolla, CA 92037, USA
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