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Liu Y, Yan M, Wang M, Luo S, Wang S, Luo Y, Xu Z, Ma W, Wen L, Li T. Stereoconvergent and Chemoenzymatic Synthesis of Tumor-Associated Glycolipid Disialosyl Globopentaosylceramide for Probing the Binding Affinity of Siglec-7. ACS CENTRAL SCIENCE 2024; 10:417-425. [PMID: 38435515 PMCID: PMC10906248 DOI: 10.1021/acscentsci.3c01170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 01/08/2024] [Accepted: 01/08/2024] [Indexed: 03/05/2024]
Abstract
Disialosyl globopentaosylceramide (DSGb5) is a tumor-associated complex glycosphingolipid. However, the accessibility of structurally well-defined DSGb5 for precise biological functional studies remains challenging. Herein, we describe the first total synthesis of DSGb5 glycolipid by an efficient chemoenzymatic approach. A Gb5 pentasaccharide-sphingosine was chemically synthesized by a convergent and stereocontrolled [2 + 3] method using an oxazoline disaccharide donor to exclusively form β-anomeric linkage. After investigating the substrate specificity of different sialyltransferases, regio- and stereoselective installment of two sialic acids was achieved by two sequential enzyme-catalyzed reactions using α2,3-sialyltransferase Cst-I and α2,6-sialyltransferase ST6GalNAc5. A unique aspect of the approach is that methyl-β-cyclodextrin-assisted enzymatic α2,6-sialylation of glycolipid substrate enables installment of the challenging internal α2,6-linked sialoside to synthesize DSGb5 glycosphingolipid. Surface plasmon resonance studies indicate that DSGb5 glycolipid exhibits better binding affinity for Siglec-7 than the oligosaccharide moiety of DSGb5. The binding results suggest that the ceramide moiety of DSGb5 facilitates its binding by presenting multivalent interactions of glycan epitope for the recognition of Siglec-7.
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Affiliation(s)
- Yating Liu
- State
Key Laboratory of Chemical Biology, Shanghai
Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- School
of Chinese Materia Medica, Nanjing University
of Chinese Medicine, Nanjing 210023, China
| | - Mengkun Yan
- State
Key Laboratory of Chemical Biology, Shanghai
Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- University
of Chinese Academy of Sciences, Beijing 100049, China
| | - Minghui Wang
- State
Key Laboratory of Chemical Biology, Shanghai
Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Shiwei Luo
- State
Key Laboratory of Chemical Biology, Shanghai
Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- School
of Chinese Materia Medica, Nanjing University
of Chinese Medicine, Nanjing 210023, China
| | - Shasha Wang
- State
Key Laboratory of Chemical Biology, Shanghai
Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- School
of Chinese Materia Medica, Nanjing University
of Chinese Medicine, Nanjing 210023, China
| | - Yawen Luo
- State
Key Laboratory of Chemical Biology, Shanghai
Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- University
of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhuojia Xu
- State
Key Laboratory of Chemical Biology, Shanghai
Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- University
of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenjing Ma
- State
Key Laboratory of Chemical Biology, Shanghai
Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- University
of Chinese Academy of Sciences, Beijing 100049, China
| | - Liuqing Wen
- State
Key Laboratory of Chemical Biology, Shanghai
Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- School
of Chinese Materia Medica, Nanjing University
of Chinese Medicine, Nanjing 210023, China
- University
of Chinese Academy of Sciences, Beijing 100049, China
| | - Tiehai Li
- State
Key Laboratory of Chemical Biology, Shanghai
Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- School
of Chinese Materia Medica, Nanjing University
of Chinese Medicine, Nanjing 210023, China
- University
of Chinese Academy of Sciences, Beijing 100049, China
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2
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Sauvageau J, Koyuturk I, St Michael F, Brochu D, Goneau MF, Schoenhofen I, Perret S, Star A, Robotham A, Haqqani A, Kelly J, Gilbert M, Durocher Y. Simplifying glycan monitoring of complex antigens such as the SARS-CoV-2 spike to accelerate vaccine development. Commun Chem 2023; 6:189. [PMID: 37684364 PMCID: PMC10491790 DOI: 10.1038/s42004-023-00988-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Accepted: 08/18/2023] [Indexed: 09/10/2023] Open
Abstract
Glycosylation is a key quality attribute that must be closely monitored for protein therapeutics. Established assays such as HILIC-Fld of released glycans and LC-MS of glycopeptides work well for glycoproteins with a few glycosylation sites but are less amenable for those with multiple glycosylation sites, resulting in complex datasets that are time consuming to generate and difficult to analyze. As part of efforts to improve preparedness for future pandemics, researchers are currently assessing where time can be saved in the vaccine development and production process. In this context, we evaluated if neutral and acidic monosaccharides analysis via HPAEC-PAD could be used as a rapid and robust alternative to LC-MS and HILIC-Fld for monitoring glycosylation between protein production batches. Using glycoengineered spike proteins we show that the HPAEC-PAD monosaccharide assays could quickly and reproducibly detect both major and minor glycosylation differences between batches. Moreover, the monosaccharide results aligned well with those obtained by HILIC-Fld and LC-MS.
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Affiliation(s)
- Janelle Sauvageau
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada.
| | - Izel Koyuturk
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Université de Montréal, Montréal, H3C 3J7, Canada
- Human Health Therapeutics Research Centre, National Research Council of Canada, 6100 Avenue Royalmount, Montréal, QC, H4P 2R2, Canada
| | - Frank St Michael
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Denis Brochu
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Marie-France Goneau
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Ian Schoenhofen
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Sylvie Perret
- Human Health Therapeutics Research Centre, National Research Council of Canada, 6100 Avenue Royalmount, Montréal, QC, H4P 2R2, Canada
| | - Alexandra Star
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Anna Robotham
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Arsalan Haqqani
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - John Kelly
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Michel Gilbert
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Yves Durocher
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Université de Montréal, Montréal, H3C 3J7, Canada
- Human Health Therapeutics Research Centre, National Research Council of Canada, 6100 Avenue Royalmount, Montréal, QC, H4P 2R2, Canada
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3
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Sanda M, Yang Q, Zong G, Chen H, Zheng Z, Dhani H, Khan K, Kroemer A, Wang LX, Goldman R. LC-MS/MS-PRM Quantification of IgG Glycoforms Using Stable Isotope Labeled IgG1 Fc Glycopeptide Standard. J Proteome Res 2023; 22:1138-1147. [PMID: 36763792 PMCID: PMC10461028 DOI: 10.1021/acs.jproteome.2c00475] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Indexed: 02/12/2023]
Abstract
Targeted quantification of proteins is a standard methodology with broad utility, but targeted quantification of glycoproteins has not reached its full potential. The lack of optimized workflows and isotopically labeled standards limits the acceptance of glycoproteomics quantification. In this work, we introduce an efficient and streamlined chemoenzymatic synthesis of a library of isotopically labeled glycopeptides of IgG1 which we use for quantification in an energy optimized LC-MS/MS-PRM workflow. Incorporation of the stable isotope labeled N-acetylglucosamine enables an efficient monitoring of all major fragment ions of the glycopeptides generated under the soft higher-energy C-trap dissociation (HCD) conditions, which reduces the coefficients of variability (CVs) of the quantification to 0.7-2.8%. Our results document, for the first time, that the workflow using a combination of stable isotope labeled standards with intrascan normalization enables quantification of the glycopeptides by an electron transfer dissociation (ETD) workflow, as well as the HCD workflow, with the highest sensitivity compared to traditional workflows. This was exemplified by a rapid quantification (13 min) of IgG1 Fc glycoforms from COVID-19 patients.
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Affiliation(s)
- Miloslav Sanda
- Department
of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, D.C. 20057, United States
- Clinical
and Translational Glycoscience Research Center, Georgetown University, Washington, D.C. 20057, United States
- Max-Planck-Institut
fuer Herz- und Lungenforschung, Ludwigstrasse 43, Bad Nauheim, 61231, Germany
| | - Qiang Yang
- GlycoT Therapeutics, College Park, Maryland 20742, United States
| | - Guanghui Zong
- Department
of Chemistry and Biochemistry, University
of Maryland, College
Park, Maryland 20742, United States
| | - He Chen
- GlycoT Therapeutics, College Park, Maryland 20742, United States
| | - Zhihao Zheng
- GlycoT Therapeutics, College Park, Maryland 20742, United States
| | - Harmeet Dhani
- MedStar Georgetown
Transplant Institute, MedStar Georgetown University Hospital and the
Center for Translational Transplant Medicine, Georgetown University Medical Center, Washington, D.C. 20057, United States
| | - Khalid Khan
- MedStar Georgetown
Transplant Institute, MedStar Georgetown University Hospital and the
Center for Translational Transplant Medicine, Georgetown University Medical Center, Washington, D.C. 20057, United States
| | - Alexander Kroemer
- MedStar Georgetown
Transplant Institute, MedStar Georgetown University Hospital and the
Center for Translational Transplant Medicine, Georgetown University Medical Center, Washington, D.C. 20057, United States
| | - Lai-Xi Wang
- Department
of Chemistry and Biochemistry, University
of Maryland, College
Park, Maryland 20742, United States
| | - Radoslav Goldman
- Department
of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, D.C. 20057, United States
- Clinical
and Translational Glycoscience Research Center, Georgetown University, Washington, D.C. 20057, United States
- Department
of Biochemistry and Molecular & Cell Biology, Georgetown University, Washington, D.C. 20057, United States
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4
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Gonzalez-Rodriguez E, Zol-Hanlon M, Bineva-Todd G, Marchesi A, Skehel M, Mahoney KE, Roustan C, Borg A, Di Vagno L, Kjær S, Wrobel AG, Benton DJ, Nawrath P, Flitsch SL, Joshi D, González-Ramírez A, Wilkinson KA, Wilkinson RJ, Wall EC, Hurtado-Guerrero R, Malaker SA, Schumann B. O-Linked Sialoglycans Modulate the Proteolysis of SARS-CoV-2 Spike and Likely Contribute to the Mutational Trajectory in Variants of Concern. ACS CENTRAL SCIENCE 2023; 9:393-404. [PMID: 36968546 PMCID: PMC10037455 DOI: 10.1021/acscentsci.2c01349] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Indexed: 06/18/2023]
Abstract
The emergence of a polybasic cleavage motif for the protease furin in SARS-CoV-2 spike has been established as a major factor for human viral transmission. The region N-terminal to that motif is extensively mutated in variants of concern (VOCs). Besides furin, spikes from these variants appear to rely on other proteases for maturation, including TMPRSS2. Glycans near the cleavage site have raised questions about proteolytic processing and the consequences of variant-borne mutations. Here, we identify that sialic acid-containing O-linked glycans on Thr678 of SARS-CoV-2 spike influence furin and TMPRSS2 cleavage and posit O-linked glycosylation as a likely driving force for the emergence of VOC mutations. We provide direct evidence that the glycosyltransferase GalNAc-T1 primes glycosylation at Thr678 in the living cell, an event that is suppressed by mutations in the VOCs Alpha, Delta, and Omicron. We found that the sole incorporation of N-acetylgalactosamine did not impact furin activity in synthetic O-glycopeptides, but the presence of sialic acid reduced the furin rate by up to 65%. Similarly, O-glycosylation with a sialylated trisaccharide had a negative impact on TMPRSS2 cleavage. With a chemistry-centered approach, we substantiate O-glycosylation as a major determinant of spike maturation and propose disruption of O-glycosylation as a substantial driving force for VOC evolution.
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Affiliation(s)
- Edgar Gonzalez-Rodriguez
- Chemical
Glycobiology Laboratory, The Francis Crick
Institute, NW1 1AT London, United Kingdom
- Department
of Chemistry, Imperial College London, W12 0BZ London, United Kingdom
| | - Mia Zol-Hanlon
- Chemical
Glycobiology Laboratory, The Francis Crick
Institute, NW1 1AT London, United Kingdom
- Signalling
and Structural Biology Lab, The Francis
Crick Institute, NW1 1AT London, United Kingdom
| | - Ganka Bineva-Todd
- Chemical
Glycobiology Laboratory, The Francis Crick
Institute, NW1 1AT London, United Kingdom
| | - Andrea Marchesi
- Chemical
Glycobiology Laboratory, The Francis Crick
Institute, NW1 1AT London, United Kingdom
- Department
of Chemistry, Imperial College London, W12 0BZ London, United Kingdom
| | - Mark Skehel
- Proteomics
Science Technology Platform, The Francis
Crick Institute, NW1 1AT London, United Kingdom
| | - Keira E. Mahoney
- Department
of Chemistry, Yale University, 275 Prospect Street, 06511 New Haven, Connecticut, United States
| | - Chloë Roustan
- Structural
Biology Science Technology Platform, The
Francis Crick Institute, NW1 1AT London, United Kingdom
| | - Annabel Borg
- Structural
Biology Science Technology Platform, The
Francis Crick Institute, NW1 1AT London, United Kingdom
| | - Lucia Di Vagno
- Chemical
Glycobiology Laboratory, The Francis Crick
Institute, NW1 1AT London, United Kingdom
- Proteomics
Science Technology Platform, The Francis
Crick Institute, NW1 1AT London, United Kingdom
| | - Svend Kjær
- Structural
Biology Science Technology Platform, The
Francis Crick Institute, NW1 1AT London, United Kingdom
| | - Antoni G. Wrobel
- Structural
Biology of Disease Processes Laboratory, Francis Crick Institute, NW1 1AT London, United Kingdom
| | - Donald J. Benton
- Structural
Biology of Disease Processes Laboratory, Francis Crick Institute, NW1 1AT London, United Kingdom
| | - Philipp Nawrath
- Structural
Biology of Disease Processes Laboratory, Francis Crick Institute, NW1 1AT London, United Kingdom
| | - Sabine L. Flitsch
- Manchester
Institute of Biotechnology, University of
Manchester, 131 Princess Street, M1 7DN Manchester, United Kingdom
| | - Dhira Joshi
- Chemical
Biology Science Technology Platform, The
Francis Crick Institute, NW1 1AT London, United Kingdom
| | | | - Katalin A. Wilkinson
- Tuberculosis
Laboratory, The Francis Crick Institute, NW1 1AT London, United Kingdom
- Wellcome
Centre for Infectious Diseases Research in Africa, University of Cape Town, 7925 Observatory, Cape Town, South Africa
| | - Robert J. Wilkinson
- Tuberculosis
Laboratory, The Francis Crick Institute, NW1 1AT London, United Kingdom
- Wellcome
Centre for Infectious Diseases Research in Africa, University of Cape Town, 7925 Observatory, Cape Town, South Africa
- Department
of Infectious Diseases, Imperial College
London, W12 0NN London, United Kingdom
- Institute
of Infectious Disease and Molecular Medicine and Department of Medicine, University of Cape Town, 7925 Observatory, Cape Town, South Africa
| | - Emma C. Wall
- The Francis
Crick Institute, NW1 1AT London, United Kingdom
- University
College London Hospitals (UCLH) Biomedical Research Centre, W1T 7DN London, United Kingdom
| | - Ramón Hurtado-Guerrero
- Institute
of Biocomputation and Physics of Complex Systems, University of Zaragoza, 50018 Zaragoza, Spain
- Copenhagen
Center for Glycomics, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
- Fundación
ARAID, 50018 Zaragoza, Spain
| | - Stacy A. Malaker
- Department
of Chemistry, Yale University, 275 Prospect Street, 06511 New Haven, Connecticut, United States
| | - Benjamin Schumann
- Chemical
Glycobiology Laboratory, The Francis Crick
Institute, NW1 1AT London, United Kingdom
- Department
of Chemistry, Imperial College London, W12 0BZ London, United Kingdom
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5
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Sanda M, Yang Q, Zong G, Chen H, Zheng Z, Dhani H, Khan K, Kroemer A, Wang LX, Goldman R. LC-MS/MS-PRM Quantification of IgG glycoforms using stable isotope labeled IgG1 Fc glycopeptide standard. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2022:2022.08.02.501850. [PMID: 35982648 PMCID: PMC9387126 DOI: 10.1101/2022.08.02.501850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Targeted quantification of proteins is a standard methodology with broad utility, but targeted quantification of glycoproteins has not reached its full potential. The lack of optimized workflows and isotopically labeled standards limits the acceptance of glycoproteomics quantification. In this paper, we introduce an efficient and streamlined chemoenzymatic synthesis of a library of isotopically labeled glycopeptides of IgG1 which we use for quantification in an energy optimized LC-MS/MS-PRM workflow. Incorporation of the stable isotope labeled N-acetylglucosamine enables an efficient monitoring of all major fragment ions of the glycopeptides generated under the soft collision induced dissociation (CID) conditions which reduces the CVs of the quantification to 0.7-2.8%. Our results document, for the first time, that the workflow using a combination of stable isotope labeled standards with intra-scan normalization enables quantification of the glycopeptides by an electron transfer dissociation (ETD) workflow as well as the CID workflow with the highest sensitivity compared to traditional workflows., This was exemplified by a rapid quantification (13-minute) of IgG1 Fc glycoforms from COVID-19 patients. Graphic Abstract
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6
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Huang K, Li C, Zong G, Prabhu SK, Chapla DG, Moremen KW, Wang LX. Site-selective sulfation of N-glycans by human GlcNAc-6-O-sulfotransferase 1 (CHST2) and chemoenzymatic synthesis of sulfated antibody glycoforms. Bioorg Chem 2022; 128:106070. [PMID: 35939855 DOI: 10.1016/j.bioorg.2022.106070] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/23/2022] [Accepted: 07/28/2022] [Indexed: 11/02/2022]
Abstract
Sulfation is a common modification of glycans and glycoproteins. Sulfated N-glycans have been identified in various glycoproteins and implicated for biological functions, but in vitro synthesis of structurally well-defined full length sulfated N-glycans remains to be described. We report here the first in vitro enzymatic sulfation of biantennary complex type N-glycans by recombinant human CHST2 (GlcNAc-6-O-sulfotransferase 1, GlcNAc6ST-1). We found that the sulfotransferase showed high antennary preference and could selectively sulfate the GlcNAc moiety located on the Manα1,3Man arm of the biantennary N-glycan. The glycan chain was further elongated by bacterial β1,4 galactosyltransferase from Neiserria meningitidis and human β1,4 galactosyltransferase IV(B4GALT4), which led to the formation of different sulfated N-glycans. Using rituximab as a model IgG antibody, we further demonstrated that the sulfated N-glycans could be efficiently transferred to an intact antibody by using a chemoenzymatic Fc glycan remodeling method, providing homogeneous sulfated glycoforms of antibodies. Preliminary binding analysis indicated that sulfation did not affect the apparent affinity of the antibody for FcγIIIa receptor.
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Affiliation(s)
- Kun Huang
- Department of Chemistry and Biochemistry, University of Maryland, 8051 Regents Drive, College Park, MD 20742, United States
| | - Chao Li
- Department of Chemistry and Biochemistry, University of Maryland, 8051 Regents Drive, College Park, MD 20742, United States
| | - Guanghui Zong
- Department of Chemistry and Biochemistry, University of Maryland, 8051 Regents Drive, College Park, MD 20742, United States
| | - Sunaina Kiran Prabhu
- Department of Chemistry and Biochemistry, University of Maryland, 8051 Regents Drive, College Park, MD 20742, United States
| | - Digantkumar G Chapla
- Complex Carbohydrate Research Center, University of Georgia, Athens 30602, Georgia
| | - Kelley W Moremen
- Complex Carbohydrate Research Center, University of Georgia, Athens 30602, Georgia
| | - Lai-Xi Wang
- Department of Chemistry and Biochemistry, University of Maryland, 8051 Regents Drive, College Park, MD 20742, United States.
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7
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Zong G, Toonstra C, Yang Q, Zhang R, Wang LX. Chemoenzymatic Synthesis and Antibody Binding of HIV-1 V1/V2 Glycopeptide-Bacteriophage Q β Conjugates as a Vaccine Candidate. Int J Mol Sci 2021; 22:ijms222212538. [PMID: 34830420 PMCID: PMC8617853 DOI: 10.3390/ijms222212538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/19/2021] [Accepted: 11/19/2021] [Indexed: 11/18/2022] Open
Abstract
The broadly neutralizing antibody PG9 recognizes a unique glycopeptide epitope in the V1V2 domain of HIV-1 gp120 envelope glycoprotein. The present study describes the design, synthesis, and antibody-binding analysis of HIV-1 V1V2 glycopeptide-Qβ conjugates as a mimic of the proposed neutralizing epitope of PG9. The glycopeptides were synthesized using a highly efficient chemoenzymatic method. The alkyne-tagged glycopeptides were then conjugated to the recombinant bacteriophage (Qβ), a virus-like nanoparticle, through a click reaction. Antibody-binding analysis indicated that the synthetic glycoconjugates showed significantly enhanced affinity for antibody PG9 compared with the monomeric glycopeptides. It was also shown that the affinity of the Qβ-conjugates for antibody PG9 was dependent on the density of the glycopeptide antigen display. The glycopeptide-Qβ conjugates synthesized represent a promising candidate of HIV-1 vaccine.
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