1
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Montoya AL, Gil ER, Vinales I, Estevao IL, Taboada P, Torrico MC, Torrico F, Marco JD, Almeida IC, Michael K. Big is not better: Comparing two alpha-Gal-bearing glycotopes in neoglycoproteins as biomarkers for Leishmania (Viannia) braziliensis infection. Carbohydr Res 2024; 536:109015. [PMID: 38198982 DOI: 10.1016/j.carres.2023.109015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 12/15/2023] [Accepted: 12/15/2023] [Indexed: 01/12/2024]
Abstract
The protozoan parasite Leishmania (Viannia) braziliensis is among Latin America's most widespread Leishmania species and is responsible for tegumentary leishmaniasis (TL). This disease has multiple clinical presentations, with cutaneous leishmaniasis (CL) being the most frequent. It manifests as one or a few localized skin ulcers, which can spread to other body areas. Hence, early diagnosis and treatment, typically with pentavalent antimonials, is critical. Traditional diagnostic methods, like parasite culture, microscopy, or the polymerase chain reaction (PCR) for detection of the parasite DNA, have limitations due to the uneven distribution of parasites in biopsy samples. Nonetheless, studies have revealed high levels of parasite-specific anti-α-Gal antibodies in L. (V.) braziliensis-infected patients. Previously, we demonstrated that the neoglycoprotein NGP28b, consisting of the L. (Leishmania) major type-2 glycoinositolphospholipid (GIPL)-3-derived trisaccharide Galpα1,6Galpα1,3Galfβ conjugated to bovine serum albumin (BSA) via a linker, acts as a reliable serological biomarker (BMK) for L. (V.) braziliensis infection in Brazil. This indicates the presence of GIPL-3 or a similar structure in this parasite, and its terminal trisaccharide either functions as or is part of an immunodominant glycotope. Here, we explored whether extending the trisaccharide with a mannose unit would enhance its efficacy as a biomarker for the serological detection of L. (V.) braziliensis. We synthesized the tetrasaccharide Galpα1,6Galpα1,3Galfβ1,3Manpα(CH2)3SH (G31SH) and conjugated it to maleimide-functionalized BSA to afford NGP31b. When we assessed the efficacy of NGP28b and NGP31b by chemiluminescent enzyme-linked immunosorbent assay on a cohort of CL patients with L. (V.) braziliensis infection from Bolivia and Argentina against a healthy control group, both NGPs exhibited similar or identical sensitivity, specificity, and accuracy. This finding implies that the mannose moiety at the reducing end is not part of the glycotope recognized by the parasite-specific anti-α-Gal antibodies in patients' sera, nor does it exert a relevant influence on the terminal trisaccharide's conformation. Moreover, the mannose does not seem to inhibit glycan-antibody interactions. Therefore, NGP31b is a viable and dependable BMK for the serodiagnosis of CL caused by L. (V.) braziliensis.
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Affiliation(s)
- Alba L Montoya
- Department of Chemistry and Biochemistry, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA
| | - Eileni R Gil
- Department of Chemistry and Biochemistry, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA
| | - Irodiel Vinales
- Department of Chemistry and Biochemistry, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA
| | - Igor L Estevao
- Department of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA
| | - Paola Taboada
- Department of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA
| | - Mary Cruz Torrico
- Universidad Mayor de San Simón, Faculty of Medicine, and Fundación CEADES, Cochabamba, Bolivia
| | - Faustino Torrico
- Universidad Mayor de San Simón, Faculty of Medicine, and Fundación CEADES, Cochabamba, Bolivia
| | - Jorge Diego Marco
- Universidad Nacional de Salta (UNSa)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Patología Experimental, Facultad de Ciencias de la Salud, Universidad Nacional de Salta, Salta, Argentina
| | - Igor C Almeida
- Department of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA.
| | - Katja Michael
- Department of Chemistry and Biochemistry, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA.
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2
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Montoya AL, Austin VM, Portillo S, Vinales I, Ashmus RA, Estevao I, Jankuru SR, Alraey Y, Al-Salem WS, Acosta-Serrano Á, Almeida IC, Michael K. Reversed Immunoglycomics Identifies α-Galactosyl-Bearing Glycotopes Specific for Leishmania major Infection. JACS AU 2021; 1:1275-1287. [PMID: 34467365 PMCID: PMC8397363 DOI: 10.1021/jacsau.1c00201] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Indexed: 06/13/2023]
Abstract
All healthy humans have high levels of natural anti-α-galactosyl (α-Gal) antibodies (elicited by yet uncharacterized glycotopes), which may play important roles in immunoglycomics: (a) potential protection against certain parasitic and viral zoonotic infections; (b) targeting of α-Gal-engineered cancer cells; (c) aiding in tissue repair; and (d) serving as adjuvants in α-Gal-based vaccines. Patients with certain protozoan infections have specific anti-α-Gal antibodies, elicited against parasite-derived α-Gal-bearing glycotopes. These glycotopes, however, remain elusive except for the well-characterized glycotope Galα1,3Galβ1,4GlcNAcα, expressed by Trypanosoma cruzi. The discovery of new parasitic glycotopes is greatly hindered by the enormous structural diversity of cell-surface glycans and the technical challenges of classical immunoglycomics, a top-down approach from cultivated parasites to isolated glycans. Here, we demonstrate that reversed immunoglycomics, a bottom-up approach, can identify parasite species-specific α-Gal-bearing glycotopes by probing synthetic oligosaccharides on neoglycoproteins. This method was tested here seeking to identify as-yet unknown glycotopes specific for Leishmania major, the causative agent of Old-World cutaneous leishmaniasis (OWCL). Neoglycoproteins decorated with synthetic α-Gal-containing oligosaccharides derived from L. major glycoinositolphospholipids served as antigens in a chemiluminescent enzyme-linked immunosorbent assay using sera from OWCL patients and noninfected individuals. Receiver-operating characteristic analysis identified Galpα1,3Galfβ and Galpα1,3Galfβ1,3Manpα glycotopes as diagnostic biomarkers for L. major-caused OWCL, which can distinguish with 100% specificity from heterologous diseases and L. tropica-caused OWCL. These glycotopes could prove useful in the development of rapid α-Gal-based diagnostics and vaccines for OWCL. Furthermore, this method could help unravel cryptic α-Gal-glycotopes of other protozoan parasites and enterobacteria that elicit the natural human anti-α-Gal antibodies.
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Affiliation(s)
- Alba L. Montoya
- Department
of Chemistry and Biochemistry, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, United States
| | - Victoria M. Austin
- Department
of Vector Biology, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United
Kingdom
| | - Susana Portillo
- Department
of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, United States
| | - Irodiel Vinales
- Department
of Chemistry and Biochemistry, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, United States
| | - Roger A. Ashmus
- Department
of Chemistry and Biochemistry, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, United States
| | - Igor Estevao
- Department
of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, United States
| | - Sohan R. Jankuru
- Department
of Chemistry and Biochemistry, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, United States
| | - Yasser Alraey
- Department
of Vector Biology, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United
Kingdom
| | - Waleed S. Al-Salem
- Department
of Vector Biology, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United
Kingdom
| | - Álvaro Acosta-Serrano
- Department
of Vector Biology, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United
Kingdom
| | - Igor C. Almeida
- Department
of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, United States
| | - Katja Michael
- Department
of Chemistry and Biochemistry, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, United States
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3
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Wang L, Guo Z. An extensive review of studies on mycobacterium cell wall polysaccharide-related oligosaccharides – part I: Synthetic studies on arabinofuranosyl oligosaccharides. J Carbohydr Chem 2019. [DOI: 10.1080/07328303.2019.1630839] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Lizhen Wang
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji'nan, China
| | - Zhongwu Guo
- Department of Chemistry, University of Florida, Gainesville, FL, USA
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4
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Kulkarni SS, Wang CC, Sabbavarapu NM, Podilapu AR, Liao PH, Hung SC. "One-Pot" Protection, Glycosylation, and Protection-Glycosylation Strategies of Carbohydrates. Chem Rev 2018; 118:8025-8104. [PMID: 29870239 DOI: 10.1021/acs.chemrev.8b00036] [Citation(s) in RCA: 197] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Carbohydrates, which are ubiquitously distributed throughout the three domains of life, play significant roles in a variety of vital biological processes. Access to unique and homogeneous carbohydrate materials is important to understand their physical properties, biological functions, and disease-related features. It is difficult to isolate carbohydrates in acceptable purity and amounts from natural sources. Therefore, complex saccharides with well-defined structures are often most conviently accessed through chemical syntheses. Two major hurdles, regioselective protection and stereoselective glycosylation, are faced by carbohydrate chemists in synthesizing these highly complicated molecules. Over the past few years, there has been a radical change in tackling these problems and speeding up the synthesis of oligosaccharides. This is largely due to the development of one-pot protection, one-pot glycosylation, and one-pot protection-glycosylation protocols and streamlined approaches to orthogonally protected building blocks, including those from rare sugars, that can be used in glycan coupling. In addition, new automated strategies for oligosaccharide syntheses have been reported not only for program-controlled assembly on solid support but also by the stepwise glycosylation in solution phase. As a result, various sugar molecules with highly complex, large structures could be successfully synthesized. To summarize these recent advances, this review describes the methodologies for one-pot protection and their one-pot glycosylation into the complex glycans and the chronological developments associated with automated syntheses of oligosaccharides.
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Affiliation(s)
- Suvarn S Kulkarni
- Department of Chemistry , Indian Institute of Technology Bombay , Mumbai 400076 , India
| | | | | | - Ananda Rao Podilapu
- Department of Chemistry , Indian Institute of Technology Bombay , Mumbai 400076 , India
| | - Pin-Hsuan Liao
- Institute of Chemistry , Academia Sinica , Taipei 115 , Taiwan
| | - Shang-Cheng Hung
- Genomics Research Center , Academia Sinica , Taipei 115 , Taiwan
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5
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Li HZ, Ding J, Cheng CR, Chen Y, Liang XY. β-L-Arabinofuranosylation Conducted by 5-O-(2-pyridinecarbonyl)-L-arabinofuranosyl Trichloroacetimidate. Carbohydr Res 2018; 460:1-7. [PMID: 29476991 DOI: 10.1016/j.carres.2018.02.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 02/06/2018] [Accepted: 02/07/2018] [Indexed: 11/29/2022]
Abstract
We describe a β-L-arabinofuranosylation method by employing the 5-O-(2-pyridinecarbonyl)-L-arabinofuranosyl trichloroacetimidate 10 as a donor. This approach allows a wide range of acceptor substrates, especially amino acid acceptors, to be used. Stereoselective synthesis of β-(1,4)-L-arabinofuranosyl-(2S, 4R)-4-hydroxy-L-proline (β-L-Araf-L-Hyp4) and its dimer is achieved readily by this method. Both the stereoselectivities and yields of the reactions are excellent. To demonstrate the utility of this methodology, the preparation of a trisaccharide in a one-pot manner was carried out.
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Affiliation(s)
- Hong-Zhan Li
- School of Chemistry Engineering, Sichuan University of Science & Engineering, Zigong 643000, China
| | - Jie Ding
- School of Chemistry Engineering, Sichuan University of Science & Engineering, Zigong 643000, China
| | - Chun-Ru Cheng
- School of Chemistry Engineering, Sichuan University of Science & Engineering, Zigong 643000, China
| | - Yue Chen
- School of Chemistry Engineering, Sichuan University of Science & Engineering, Zigong 643000, China
| | - Xing-Yong Liang
- School of Chemistry Engineering, Sichuan University of Science & Engineering, Zigong 643000, China.
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6
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Kinnaert C, Daugaard M, Nami F, Clausen MH. Chemical Synthesis of Oligosaccharides Related to the Cell Walls of Plants and Algae. Chem Rev 2017; 117:11337-11405. [DOI: 10.1021/acs.chemrev.7b00162] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Christine Kinnaert
- Center for Nanomedicine and
Theranostics, Department of Chemistry, Technical University of Denmark, Kemitorvet, Building 207, 2800 Kongens Lyngby, Denmark
| | - Mathilde Daugaard
- Center for Nanomedicine and
Theranostics, Department of Chemistry, Technical University of Denmark, Kemitorvet, Building 207, 2800 Kongens Lyngby, Denmark
| | - Faranak Nami
- Center for Nanomedicine and
Theranostics, Department of Chemistry, Technical University of Denmark, Kemitorvet, Building 207, 2800 Kongens Lyngby, Denmark
| | - Mads H. Clausen
- Center for Nanomedicine and
Theranostics, Department of Chemistry, Technical University of Denmark, Kemitorvet, Building 207, 2800 Kongens Lyngby, Denmark
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7
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Galactofuranose antigens, a target for diagnosis of fungal infections in humans. Future Sci OA 2017; 3:FSO199. [PMID: 28883999 PMCID: PMC5583699 DOI: 10.4155/fsoa-2017-0030] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 03/20/2017] [Indexed: 12/02/2022] Open
Abstract
The use of biomarkers for the detection of fungal infections is of interest to complement histopathological and culture methods. Since the production of antibodies in immunocompromised patients is scarce, detection of a specific antigen could be effective for early diagnosis. D-Galactofuranose (Galf) is the antigenic epitope in glycoconjugates of several pathogenic fungi. Since Galf is not biosynthesized by mammals, it is an attractive candidate for diagnosis of infection. A monoclonal antibody that recognizes Galf is commercialized for detection of aspergillosis. The linkage of Galf in the natural glycans and the chemical structures of the synthesized Galf-containing oligosaccharides are described in this paper. The oligosaccharides could be used for the synthesis of artificial carbohydrate-based antigens, not enough exploited for diagnosis. D-Galactofuranose (Galf) is the unit in polysaccharides and glycoconjugates of several pathogenic fungi that is recognized by the immune system. Since Galf is not synthesized by mammals, it is an attractive candidate for diagnosis of infection. Since the production of antibodies in immunocompromised patients is scarce, detection of a specific antigen could be effective for early diagnosis. An antibody that recognizes Galf is commercialized for the detection of aspergillosis. Chemically synthesized Galf-containing oligosaccharides, reviewed in this paper, could therefore be used for the synthesis of artificial carbohydrate-based antigens and in diagnosis.
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8
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Joe M, Lowary TL. Synthesis of a homologous series of galactofuranose-containing mycobacterial arabinogalactan fragments. CAN J CHEM 2016. [DOI: 10.1139/cjc-2016-0416] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mycobacteria, including the human pathogen Mycobacterium tuberculosis, the causative agent of tuberculosis, produce a complex cell wall structure made of carbohydrates and lipids. The major structural element of the mycobacterial cell wall is a glycoconjugate called the mycolic acid – arabinogalactan – peptidoglycan (mAGP) complex. Inhibition of mAGP biosynthesis is a proven strategy for developing anti-mycobacterial drugs, and thus, understanding the pathways and enzymes involved in the assembly of this molecule is of interest. In this paper, we describe the chemical synthesis of a panel of nine oligosaccharide fragments (4–12) of the galactan domain of the mAGP complex designed as biosynthetic probes. These structures, ranging in size from a hexasaccharide to a tetradecasaccharide, are potential substrates for two biosynthetic enzymes, GlfT2 and AftA, and represent the largest mycobacterial galactan fragments synthesized to date. The route developed was iterative and provided multimilligram quantities of the target molecules 4–12 in good overall yield.
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Affiliation(s)
- Maju Joe
- Alberta Glycomics Centre and Department of Chemistry, The University of Alberta, Edmonton, AB T6G 2G2, Canada
- Alberta Glycomics Centre and Department of Chemistry, The University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Todd L. Lowary
- Alberta Glycomics Centre and Department of Chemistry, The University of Alberta, Edmonton, AB T6G 2G2, Canada
- Alberta Glycomics Centre and Department of Chemistry, The University of Alberta, Edmonton, AB T6G 2G2, Canada
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9
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Tilve MJ, Cori CR, Gallo-Rodriguez C. Regioselective 5-O-Opening of Conformationally Locked 3,5-O-Di-tert-butylsilylene-d-galactofuranosides. Synthesis of (1→5)-β-d-Galactofuranosyl Derivatives. J Org Chem 2016; 81:9585-9594. [PMID: 27673745 DOI: 10.1021/acs.joc.6b01562] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The use of thiogalactofuranoside as donors for the construction of internal Galf containing oligosaccharide is limited, probably due to the difficulty to functionalize thiogalactofuranoside derivatives showing O-2, O-3, and O-5 with similar reactivity. An efficient method for complete regioselective 5-O-opening of conformationally restricted 3,5-O-di-tert-butylsilylene-d-galactofuranoside derivatives was developed. The use of a solution nBu4NF (1.1 equiv) in CH2Cl2 on 6 gave the 5-OH free derivative 10 as the only product (90%). 3-O-Di-tert-butylhydroxysilyl derivative 10 was stable upon purification and glycosylation reaction. Preactivation of conformationally restricted thioglycoside 6 employing p-NO2-benzensulfenyl chloride/AgOTf followed by condensation over the 5-OH thioglycoside acceptor 10 gave the corresponding disaccharide 12 without autocondensation byproduct. Regioselective 5-O-deprotection was also successfully performed over the (1→5)-β-d-galactofuranosyl di- and trisaccharide derivatives 12 and 13. This methodology allowed the differentiation between the secondary hydroxyl groups OH-3 and OH-5 of 1,2-cis or 1,2-trans d-galactofuranoside derivatives, and it still constitutes an innovative approach to access oligosaccharides of pharmacological importance.
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Affiliation(s)
- Mariano J Tilve
- CIHIDECAR, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Orgánica, Ciudad Universitaria , Pabellón II, 1428 Buenos Aires, Argentina
| | - Carmen R Cori
- CIHIDECAR, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Orgánica, Ciudad Universitaria , Pabellón II, 1428 Buenos Aires, Argentina
| | - Carola Gallo-Rodriguez
- CIHIDECAR, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Orgánica, Ciudad Universitaria , Pabellón II, 1428 Buenos Aires, Argentina
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10
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Abstract
The development of glycobiology relies on the sources of particular oligosaccharides in their purest forms. As the isolation of the oligosaccharide structures from natural sources is not a reliable option for providing samples with homogeneity, chemical means become pertinent. The growing demand for diverse oligosaccharide structures has prompted the advancement of chemical strategies to stitch sugar molecules with precise stereo- and regioselectivity through the formation of glycosidic bonds. This Review will focus on the key developments towards chemical O-glycosylations in the current century. Synthesis of novel glycosyl donors and acceptors and their unique activation for successful glycosylation are discussed. This Review concludes with a summary of recent developments and comments on future prospects.
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Affiliation(s)
- Rituparna Das
- Department of Chemical SciencesIndian Institute of Science Education and Research (IISER) KolkataMohanpurNadia741246India
| | - Balaram Mukhopadhyay
- Department of Chemical SciencesIndian Institute of Science Education and Research (IISER) KolkataMohanpurNadia741246India
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11
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Abstract
![]()
The cell surface (or cell wall) of bacteria is coated with carbohydrate
(or glycan) structures that play a number of important roles. These
include providing structural integrity, serving as a permeability
barrier to extracellular compounds (e.g., drugs) and modulating the
immune system of the host. Of interest to this Account is the cell
wall structure of mycobacteria. There are a host of different mycobacterial
species, some of which cause human disease. The most well-known is Mycobacterium tuberculosis, the causative agent of tuberculosis.
The mycobacterial cell wall is characterized by the presence of unusual
carbohydrate structures that fulfill the roles described above. However,
in many cases, a molecular-level understanding of how mycobacterial
cell wall glycans mediate these processes is lacking. Inspired
by a seminar he heard as a postdoctoral fellow, the author
began his independent research program with a focus on the chemical
synthesis of mycobacterial glycans. The goals were not only to develop
synthetic approaches to these unique structures but also to provide
molecules that could be used to probe their biological function. Initial
work addressed the preparation of fragments of two key polysaccharides,
arabinogalactan and lipoarabinomannan, which contain large numbers
of sugar residues in the furanose (five-membered) ring form. At the
time these investigations began, there were few methods reported for
the synthesis of oligosaccharides containing furanose rings. Thus,
early in the program, a major area of interest was methodology development,
particularly for the preparation of 1,2-cis-furanosides.
To solve this challenge, a range of conformationally restricted donors
have been developed, both in the author’s group and others,
which provide 1,2-cis-furanosidic linkages with high
stereoselectivity. These investigations were followed by application
of the developed
methods to the synthesis of a range of target molecules containing
arabinofuranose and galactofuranose residues. These molecules have
now found application in biochemical, immunological, and structural
biology investigations, which have shed light on their biosynthesis
and how these motifs are recognized by both the innate and adaptive
immune systems. More recently, attention has been directed toward
the synthesis
of another class of immunologically active mycobacterial cell wall
glycans, the extractable glycolipids. In this case, efforts have been
primarily on phenolic glycolipids, and the compounds synthesized have
been used to evaluate their ability to modulate cytokine release.
Over the past 20 years, the use of chemical synthesis to provide increasingly
complex glycan structures has provided significant benefit to the
burgeoning field of mycobacterial glycobiology. Through the efforts
of groups from around the globe, access to these compounds is now
possible via relatively straightforward methods. As the pool of mycobacterial
glycans continues to grow, so too will our understanding of their
role in disease, which will undoubtedly lead to new strategies to
prevent or treat mycobacterial infections.
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Affiliation(s)
- Todd L. Lowary
- Alberta Glycomics Centre
and Department of Chemistry, University of Alberta, Gunning−Lemieux
Chemistry Centre, Edmonton, Alberta T6G 2G2, Canada
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12
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Abstract
The cell surface (or cell wall) of bacteria is coated with carbohydrate (or glycan) structures that play a number of important roles. These include providing structural integrity, serving as a permeability barrier to extracellular compounds (e.g., drugs) and modulating the immune system of the host. Of interest to this Account is the cell wall structure of mycobacteria. There are a host of different mycobacterial species, some of which cause human disease. The most well-known is Mycobacterium tuberculosis, the causative agent of tuberculosis. The mycobacterial cell wall is characterized by the presence of unusual carbohydrate structures that fulfill the roles described above. However, in many cases, a molecular-level understanding of how mycobacterial cell wall glycans mediate these processes is lacking. Inspired by a seminar he heard as a postdoctoral fellow, the author began his independent research program with a focus on the chemical synthesis of mycobacterial glycans. The goals were not only to develop synthetic approaches to these unique structures but also to provide molecules that could be used to probe their biological function. Initial work addressed the preparation of fragments of two key polysaccharides, arabinogalactan and lipoarabinomannan, which contain large numbers of sugar residues in the furanose (five-membered) ring form. At the time these investigations began, there were few methods reported for the synthesis of oligosaccharides containing furanose rings. Thus, early in the program, a major area of interest was methodology development, particularly for the preparation of 1,2-cis-furanosides. To solve this challenge, a range of conformationally restricted donors have been developed, both in the author's group and others, which provide 1,2-cis-furanosidic linkages with high stereoselectivity. These investigations were followed by application of the developed methods to the synthesis of a range of target molecules containing arabinofuranose and galactofuranose residues. These molecules have now found application in biochemical, immunological, and structural biology investigations, which have shed light on their biosynthesis and how these motifs are recognized by both the innate and adaptive immune systems. More recently, attention has been directed toward the synthesis of another class of immunologically active mycobacterial cell wall glycans, the extractable glycolipids. In this case, efforts have been primarily on phenolic glycolipids, and the compounds synthesized have been used to evaluate their ability to modulate cytokine release. Over the past 20 years, the use of chemical synthesis to provide increasingly complex glycan structures has provided significant benefit to the burgeoning field of mycobacterial glycobiology. Through the efforts of groups from around the globe, access to these compounds is now possible via relatively straightforward methods. As the pool of mycobacterial glycans continues to grow, so too will our understanding of their role in disease, which will undoubtedly lead to new strategies to prevent or treat mycobacterial infections.
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Affiliation(s)
- Todd L Lowary
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta , Gunning-Lemieux Chemistry Centre, Edmonton, Alberta T6G 2G2, Canada
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13
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Zulueta MML, Janreddy D, Hung SC. One-Pot Methods for the Protection and Assembly of Sugars. Isr J Chem 2015. [DOI: 10.1002/ijch.201400171] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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14
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Wang S, Meng X, Huang W, Yang JS. Influence of silyl protections on the anomeric reactivity of galactofuranosyl thioglycosides and application of the silylated thiogalactofuranosides to one-pot synthesis of diverse β-D-oligogalactofuranosides. J Org Chem 2014; 79:10203-17. [PMID: 25310684 DOI: 10.1021/jo5018684] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe in this paper the tuning effect of silyl protecting groups on the donor reactivity of galactofuranosyl phenyl thioglycosides. Silyl ethers on the galactofuranose ring are found to have an arming effect on the glycosylation reactivity, but the cyclic 3,5-acetal protecting group decreases the reactivity. The reactive phenyl 2,6-di-O-Bz-3,5-di-O-TBS-1-thio-β-d-galactofuranoside 3 is proved to be a useful glycosyl building block. By taking advantage of this donor, we achieved the highly efficient one-pot solution-phase assembly of a panel of β-d-galactofuranosyl tri- and tetrasaccharides possessing diverse glycosidic linkages.
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Affiliation(s)
- Shuai Wang
- Key Laboratory of Drug Targeting, Ministry of Education, and Department of Chemistry of Medicinal Natural Products, West China School of Pharmacy, Sichuan University , Chengdu 610041, P. R. China
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Tilve MJ, Gallo-Rodriguez C. Conformationally restricted 3,5-O-(di-tert-butylsilylene)-d-galactofuranosyl thioglycoside donor for 1,2-cis α-d-galactofuranosylation. Carbohydr Res 2014; 397:7-17. [DOI: 10.1016/j.carres.2014.07.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 07/29/2014] [Accepted: 07/30/2014] [Indexed: 01/07/2023]
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16
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Huang H, Han L, Lan YM, Zhang LL. One-pot synthesis of a 3,6-branched hexaarabinogalactan using galactopyranosyl thioglycoside diol as a key glycosylating agent. JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH 2014; 16:640-647. [PMID: 24873750 DOI: 10.1080/10286020.2014.917084] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 04/17/2014] [Indexed: 06/03/2023]
Abstract
We present in this paper the efficient four-component one-pot synthesis of a fully protected hexaarabinogalactan 2 with di-branched structure by using D-thiogalactopyranoside 3,6-diol 3 as the central glycosylating agent. After global deprotection, 2 was converted into the 3-aminopropyl linker-containing free oligosaccharide 1 that is structurally related to ALR-5IIa-1-1, an arabino-3,6-galactan with intestinal immune system modulating activity.
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Affiliation(s)
- Hong Huang
- a Department of Pharmacy , Evidence-Based Pharmacy Center, West China Second University Hospital, Sichuan University , Chengdu 610041 , China
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17
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Abstract
An analog of Mycobacterium tuberculosis lipoarabinomannan (LAM) has been synthesized containing the characteristic structures of all of its three major components; that is, a mannosylated phosphatidylinositol moiety, an oligomannan, and an oligoarabinan. A highly convergent strategy was developed that is applicable to the synthesis of other LAM analogs. The synthetic miniature LAM should be useful for various biological studies.
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Affiliation(s)
- Jian Gao
- Department
of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Guochao Liao
- Department
of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Lizhen Wang
- National
Glycoengineering Research Center, Shandong
University, Jinan 250100, China
| | - Zhongwu Guo
- Department
of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
- National
Glycoengineering Research Center, Shandong
University, Jinan 250100, China
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Marino C, Baldoni L. Synthesis of D-galactofuranose-containing molecules: design of galactofuranosyl acceptors. Chembiochem 2014; 15:188-204. [PMID: 24420700 DOI: 10.1002/cbic.201300638] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Indexed: 11/11/2022]
Abstract
D-Galactofuranose (D-Galf) is present in glycoconjugates of several pathogenic microorganisms but is absent in mammals, so it is a good target for the development of chemotherapeutic agents for the treatment of microbial infections. This fact has increased interest in the synthesis of D-Galf-containing molecules for corresponding glycobiological studies. The synthesis of oligosaccharides, glycoconjugates, and mimetics of D-Galf requires specific methods for the preparation of galactose derivatives in the furanosic configuration, the synthesis of appropriate acceptors, and efficient glycosylation methods for the construction of α- and β-D-Galf linkages. This review summarizes the different strategies developed for the preparation of partially protected derivatives of D-Galf, suitable as acceptors for the construction of (1→2), (1→3), (1→5), and (1→6) link- ages, and describes recent applications.
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Affiliation(s)
- Carla Marino
- CIHIDECAR-CONICET-UBA, Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón II, Ciudad Universitaria, 1428 Buenos Aires (Argentina).
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19
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Regioselective 6-detrimethylsilylation of per-O-TMS-protected carbohydrates in the presence of ammonium acetate. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2013.05.039] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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20
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Liang XY, Bin HC, Yang JS. Tuning effect of silyl protecting groups on the glycosylation reactivity of arabinofuranosyl thioglycosides. Org Lett 2013; 15:2834-7. [PMID: 23682928 DOI: 10.1021/ol401166x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The tuning effect of silyl protecting groups on the glycosylation reactivity of arabinofuranosyl phenyl thioglycoside donors is presented. Silyl ethers on the 3-, 5-, and 3,5-positions of the arabinofuranose ring are found to have an arming effect on the donor reactivity, whereas the cyclic 3,5-acetal type protecting groups reduce the reactivity.
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Affiliation(s)
- Xing-Yong Liang
- Key Laboratory of Drug Targeting and Drug Delivery Systems of the Ministry of Education, Department of Chemistry of Medicinal Natural Products, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
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Liang XY, Liu QW, Bin HC, Yang JS. One-pot synthesis of branched oligosaccharides by use of galacto- and mannopyranosyl thioglycoside diols as key glycosylating agents. Org Biomol Chem 2013; 11:3903-17. [DOI: 10.1039/c3ob40421h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Kashiwagi GA, Mendoza VM, de Lederkremer RM, Gallo-Rodriguez C. Synthesis of the O-linked hexasaccharide containing β-D-Galf-(1→2)-β-D-Galf in Trypanosoma cruzi mucins. Org Biomol Chem 2012; 10:6322-32. [PMID: 22735493 DOI: 10.1039/c2ob25741f] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The hexasaccharide β-D-Galp-(1→2)-[β-D-Galp-(1→3)]-β-D-Galp-(1→6)-[β-D-Galf(1→2)-β-D-Galf(1→4)]-D-GlcNAc (1) is the largest carbohydrate structure released as alditol by reductive β-elimination from mucins of some strains of T. cruzi. The terminal β-D-Galp units are sites of sialylation by trans-sialidase which transfers sialic acid from the host to the parasite. Hexasaccharide 1 was synthesized by a [3 + 3]-convergent strategy based on a nitrile assisted glycosylation, using the trichloroacetimidate method. The β-D-Galf-(1→2)-β-D-Galf-D-GlcNAc synthon was sequentially constructed from the reducing end to the non-reducing end employing benzyl α-D-galactofuranoside as starting material for the internal Galf unit. The choice of this novel precursor, obtained in one-reaction step from galactose, allowed the introduction of an orthogonal and participating levulinoyl group at O-2. Thus, the diastereoselective construction of the Galf-β(1→4)-GlcNAc linkage by the trichloroacetimidate method of glycosylation was achieved. The (1)H NMR spectrum of alditol 2 was identical to the product released by β-elimination from the parasite mucin.
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Affiliation(s)
- Gustavo A Kashiwagi
- CIHIDECAR, Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón II, 1428 Buenos Aires, Argentina
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