1
|
Zhong J, Li J, Burton GJ, Koistinen H, Cheung KW, Ng EHY, Yao Y, Yeung WSB, Lee CL, Chiu PCN. The functional roles of protein glycosylation in human maternal-fetal crosstalk. Hum Reprod Update 2024; 30:81-108. [PMID: 37699855 DOI: 10.1093/humupd/dmad024] [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: 04/28/2023] [Revised: 07/20/2023] [Indexed: 09/14/2023] Open
Abstract
BACKGROUND The establishment of maternal-fetal crosstalk is vital to a successful pregnancy. Glycosylation is a post-translational modification in which glycans (monosaccharide chains) are attached to an organic molecule. Glycans are involved in many physiological and pathological processes. Human endometrial epithelium, endometrial gland secretions, decidual immune cells, and trophoblasts are highly enriched with glycoconjugates and glycan-binding molecules important for a healthy pregnancy. Aberrant glycosylation in the placenta and uterus has been linked to repeated implantation failure and various pregnancy complications, but there is no recent review summarizing the functional roles of glycosylation at the maternal-fetal interface and their associations with pathological processes. OBJECTIVE AND RATIONALE This review aims to summarize recent findings on glycosylation, glycosyltransferases, and glycan-binding receptors at the maternal-fetal interface, and their involvement in regulating the biology and pathological conditions associated with endometrial receptivity, placentation and maternal-fetal immunotolerance. Current knowledge limitations and future insights into the study of glycobiology in reproduction are discussed. SEARCH METHODS A comprehensive PubMed search was conducted using the following keywords: glycosylation, glycosyltransferases, glycan-binding proteins, endometrium, trophoblasts, maternal-fetal immunotolerance, siglec, selectin, galectin, repeated implantation failure, early pregnancy loss, recurrent pregnancy loss, preeclampsia, and fetal growth restriction. Relevant reports published between 1980 and 2023 and studies related to these reports were retrieved and reviewed. Only publications written in English were included. OUTCOMES The application of ultrasensitive mass spectrometry tools and lectin-based glycan profiling has enabled characterization of glycans present at the maternal-fetal interface and in maternal serum. The endometrial luminal epithelium is covered with highly glycosylated mucin that regulates blastocyst adhesion during implantation. In the placenta, fucose and sialic acid residues are abundantly presented on the villous membrane and are essential for proper placentation and establishment of maternal-fetal immunotolerance. Glycan-binding receptors, including selectins, sialic-acid-binding immunoglobulin-like lectins (siglecs) and galectins, also modulate implantation, trophoblast functions and maternal-fetal immunotolerance. Aberrant glycosylation is associated with repeated implantation failure, early pregnancy loss and various pregnancy complications. The current limitation in the field is that most glycobiological research relies on association studies, with few studies revealing the specific functions of glycans. Technological advancements in analytic, synthetic and functional glycobiology have laid the groundwork for further exploration of glycans in reproductive biology under both physiological and pathological conditions. WIDER IMPLICATIONS A deep understanding of the functions of glycan structures would provide insights into the molecular mechanisms underlying their involvement in the physiological and pathological regulation of early pregnancy. Glycans may also potentially serve as novel early predictive markers and therapeutic targets for repeated implantation failure, pregnancy loss, and other pregnancy complications.
Collapse
Affiliation(s)
- Jiangming Zhong
- Department of Obstetrics and Gynaecology, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R., China
- The University of Hong Kong Shenzhen Key Laboratory of Fertility Regulation, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Jianlin Li
- Department of Obstetrics and Gynaecology, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R., China
| | - Graham J Burton
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Hannu Koistinen
- Department of Clinical Chemistry and Haematology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Ka Wang Cheung
- Department of Obstetrics and Gynaecology, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R., China
| | - Ernest H Y Ng
- Department of Obstetrics and Gynaecology, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R., China
- The University of Hong Kong Shenzhen Key Laboratory of Fertility Regulation, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Yuanqing Yao
- The University of Hong Kong Shenzhen Key Laboratory of Fertility Regulation, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - William S B Yeung
- The University of Hong Kong Shenzhen Key Laboratory of Fertility Regulation, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Cheuk-Lun Lee
- Department of Obstetrics and Gynaecology, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R., China
- The University of Hong Kong Shenzhen Key Laboratory of Fertility Regulation, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Philip C N Chiu
- Department of Obstetrics and Gynaecology, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R., China
- The University of Hong Kong Shenzhen Key Laboratory of Fertility Regulation, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Shivatare SS, Shivatare VS, Wong CH. Glycoconjugates: Synthesis, Functional Studies, and Therapeutic Developments. Chem Rev 2022; 122:15603-15671. [PMID: 36174107 PMCID: PMC9674437 DOI: 10.1021/acs.chemrev.1c01032] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Glycoconjugates are major constituents of mammalian cells that are formed via covalent conjugation of carbohydrates to other biomolecules like proteins and lipids and often expressed on the cell surfaces. Among the three major classes of glycoconjugates, proteoglycans and glycoproteins contain glycans linked to the protein backbone via amino acid residues such as Asn for N-linked glycans and Ser/Thr for O-linked glycans. In glycolipids, glycans are linked to a lipid component such as glycerol, polyisoprenyl pyrophosphate, fatty acid ester, or sphingolipid. Recently, glycoconjugates have become better structurally defined and biosynthetically understood, especially those associated with human diseases, and are accessible to new drug, diagnostic, and therapeutic developments. This review describes the status and new advances in the biological study and therapeutic applications of natural and synthetic glycoconjugates, including proteoglycans, glycoproteins, and glycolipids. The scope, limitations, and novel methodologies in the synthesis and clinical development of glycoconjugates including vaccines, glyco-remodeled antibodies, glycan-based adjuvants, glycan-specific receptor-mediated drug delivery platforms, etc., and their future prospectus are discussed.
Collapse
Affiliation(s)
- Sachin S Shivatare
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Vidya S Shivatare
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Chi-Huey Wong
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| |
Collapse
|
4
|
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
Collapse
|
5
|
Comparative studies on the substrate specificity and defucosylation activity of three α-l-fucosidases using synthetic fucosylated glycopeptides and glycoproteins as substrates. Bioorg Med Chem 2021; 42:116243. [PMID: 34126284 DOI: 10.1016/j.bmc.2021.116243] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 11/24/2022]
Abstract
Core fucosylation is the attachment of an α-1,6-fucose moiety to the innermost N-acetyl glucosamine (GlcNAc) in N-glycans in mammalian systems. It plays a pivotal role in modulating the structural and biological functions of glycoproteins including therapeutic antibodies. Yet, few α-l-fucosidases appear to be capable of removing core fucose from intact glycoproteins. This paper describes a comparative study of the substrate specificity and relative activity of the human α-l-fucosidase (FucA1) and two bacterial α-l-fucosidases, the AlfC from Lactobacillus casei and the BfFuc from Bacteroides fragilis. This study was enabled by the synthesis of an array of structurally well-defined core-fucosylated substrates, including core-fucosylated N-glycopeptides and a few antibody glycoforms. It was found that AlfC and BfFuc could not remove core fucose from intact full-length N-glycopeptides or N-glycoproteins but could hydrolyze only the truncated Fucα1,6GlcNAc-peptide substrates. In contrast, the human α-l-fucosidase (FucA1) showed low activity on truncated Fucα1,6GlcNAc substrates but was able to remove core fucose from intact and full-length core-fucosylated N-glycopeptides and N-glycoproteins. In addition, it was found that FucA1 was the only α-l-fucosidase that showed low but apparent activity to remove core fucose from intact IgG antibodies. The ability of FucA1 to defucosylate intact monoclonal antibodies reveals an opportunity to evolve the human α-l-fucosidase for direct enzymatic defucosylation of therapeutic antibodies to improve their antibody-dependent cellular cytotoxicity.
Collapse
|
6
|
Qin K, Shi W, Zhao L, Li M, Tang Y, Faridoon, Jiang B, Tang F, Huang W. Thermostability detection and optimization of glycoengineered antibodies and antibody-drug conjugates based on differential scanning flouremitry analysis. Bioorg Chem 2020; 94:103391. [DOI: 10.1016/j.bioorg.2019.103391] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 10/16/2019] [Accepted: 10/21/2019] [Indexed: 01/02/2023]
|
7
|
Marqvorsen MHS, Paramasivam S, Doelman W, Fairbanks AJ, van Kasteren SI. Efficient synthesis and enzymatic extension of an N-GlcNAz asparagine building block. Chem Commun (Camb) 2019; 55:5287-5290. [PMID: 30994122 DOI: 10.1039/c9cc02051a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
N-Azidoacetyl-d-glucosamine (GlcNAz) is a particularly useful tool in chemical biology as the azide is a metabolically stable yet accessible handle within biological systems. Herein, we report a practical synthesis of FmocAsn(N-Ac3GlcNAz)OH, a building block for solid phase peptide synthesis (SPPS). Protecting group manipulations are minimised by taking advantage of the inherent chemoselectivity of phosphine-mediated azide reduction, and the resulting glycosyl amine is employed directly in the opening of Fmoc protected aspartic anhydride. We show potential application of the building block by establishing it as a substrate for enzymatic glycan extension using sugar oxazolines of varying size and biological significance with several endo-β-N-acetylglucosaminidases (ENGases). The added steric bulk resulting from incorporation of the azide is shown to have no or a minor impact on the yield of enzymatic glycan extension.
Collapse
Affiliation(s)
| | - Sivasinthujah Paramasivam
- Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
| | - Ward Doelman
- Leiden Institute of Chemistry (LIC), Division of Bio-Organic Chemistry, Einsteinweg 55, Leiden, The Netherlands.
| | - Antony John Fairbanks
- Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand and Biomolecular Interaction Centre, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
| | - Sander Izaäk van Kasteren
- Leiden Institute of Chemistry (LIC), Division of Bio-Organic Chemistry, Einsteinweg 55, Leiden, The Netherlands.
| |
Collapse
|
8
|
Abstract
Glycosylation is one of the most prevalent posttranslational modifications that profoundly affects the structure and functions of proteins in a wide variety of biological recognition events. However, the structural complexity and heterogeneity of glycoproteins, usually resulting from the variations of glycan components and/or the sites of glycosylation, often complicates detailed structure-function relationship studies and hampers the therapeutic applications of glycoproteins. To address these challenges, various chemical and biological strategies have been developed for producing glycan-defined homogeneous glycoproteins. This review highlights recent advances in the development of chemoenzymatic methods for synthesizing homogeneous glycoproteins, including the generation of various glycosynthases for synthetic purposes, endoglycosidase-catalyzed glycoprotein synthesis and glycan remodeling, and direct enzymatic glycosylation of polypeptides and proteins. The scope, limitation, and future directions of each method are discussed.
Collapse
Affiliation(s)
- Chao Li
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Lai-Xi Wang
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| |
Collapse
|
9
|
Fairbanks AJ. The ENGases: versatile biocatalysts for the production of homogeneous N-linked glycopeptides and glycoproteins. Chem Soc Rev 2018; 46:5128-5146. [PMID: 28681051 DOI: 10.1039/c6cs00897f] [Citation(s) in RCA: 118] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The endo-β-N-acetylglucosaminidases (ENGases) are an enzyme class (EC 3.2.1.96) produced by a range of organisms, ranging from bacteria, through fungi, to higher order species, including humans, comprising two-sub families of glycosidases which all cleave the chitobiose core of N-linked glycans. Synthetic applications of these enzymes, i.e. to catalyse the reverse of their natural hydrolytic mode of action, allow the attachment of N-glycans to a wide variety of substrates which contain an N-acetylglucosamine (GlcNAc) residue to act as an 'acceptor' handle. The use of N-glycan oxazolines, high energy intermediates on the hydrolytic pathway, as activated donors allows their high yielding attachment to almost any amino acid, peptide or protein that contains a GlcNAc residue as an acceptor. The synthetic effectiveness of these biocatalysts has been significantly increased by the production of mutant glycosynthases; enzymes which can still catalyse synthetic processes using oxazolines as donors, but which do not hydrolyse the reaction products. ENGase biocatalysts are now finding burgeoning application for the production of biologically active glycopeptides and glycoproteins, including therapeutic monoclonal antibodies (mAbs) for which the oligosaccharides have been remodelled to optimise effector functions.
Collapse
Affiliation(s)
- Antony J Fairbanks
- Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.
| |
Collapse
|
10
|
Calderon AD, Li L, Wang PG. FUT8: from biochemistry to synthesis of core-fucosylated N-glycans. PURE APPL CHEM 2017. [DOI: 10.1515/pac-2016-0923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Glycosylation is a major posttranslational modification of proteins. Modification in structure on N-glycans leads to many diseases. One of such modifications is core α-1,6 fucosylation, which is only found in eukaryotes. For this reason, lots of research has been done on approaches to synthesize core-fucosylated N-glycans both chemically and enzymatically, in order to have well defined structures that can be used as probes for glycan analysis and identifying functions of glycan-binding proteins. This review will focus on FUT8, the enzyme responsible for core fucosylation in mammals and the strategies that have been developed for the synthesis of core fucosylated N-glycans have been synthesized so far.
Collapse
Affiliation(s)
- Angie D. Calderon
- Department of Chemistry and Center for Diagnostics and Therapeutics , Georgia State University , Atlanta , GA 30303 , USA
| | - Lei Li
- Department of Chemistry and Center for Diagnostics and Therapeutics , Georgia State University , Atlanta , GA 30303 , USA
| | - Peng G. Wang
- Department of Chemistry and Center for Diagnostics and Therapeutics , Georgia State University , Atlanta , GA 30303 , USA
| |
Collapse
|
11
|
Orwenyo J, Cai H, Giddens J, Amin MN, Toonstra C, Wang LX. Systematic Synthesis and Binding Study of HIV V3 Glycopeptides Reveal the Fine Epitopes of Several Broadly Neutralizing Antibodies. ACS Chem Biol 2017; 12:1566-1575. [PMID: 28414420 DOI: 10.1021/acschembio.7b00319] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A class of new glycan-reactive broadly neutralizing antibodies represented by PGT121, 10-1074, and PGT128 has recently been discovered that targets specific N-glycans and the peptide region around the V3 domain. However, the glycan specificity and fine epitopes of these bNAbs remain to be further defined. We report here a systematic chemoenzymatic synthesis of homogeneous V3 glycopeptides derived from the HIV-1 JR-FL strain carrying defined N-glycans at N332, N301, and N295 sites. Antibody binding studies revealed that both the nature and site of glycosylation in the context of the V3 domain were critical for high-affinity binding. It was found that antibody PGT128 exhibited specificity for high-mannose N-glycan with glycosylation site promiscuity, PGT121 showed binding specificity for glycopeptide carrying a sialylated N-glycan at N301 site, and 10-1074 was specific for glycopeptide carrying a high-mannose N-glycan at N332 site. The synthesis and binding studies permit a detailed assessment of the glycan specificity and the requirement of peptide in the context of antibody-antigen recognition. The identified glycopeptides can be used as potential templates for HIV vaccine design.
Collapse
Affiliation(s)
- Jared Orwenyo
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland, United States
| | - Hui Cai
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland, United States
| | - John Giddens
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland, United States
| | - Mohammed N. Amin
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland, United States
| | - Christian Toonstra
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland, United States
| | - Lai-Xi Wang
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland, United States
| |
Collapse
|
12
|
Li C, Wang LX. Endoglycosidases for the Synthesis of Polysaccharides and Glycoconjugates. Adv Carbohydr Chem Biochem 2016; 73:73-116. [PMID: 27816108 DOI: 10.1016/bs.accb.2016.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Recent advances in glycobiology have implicated essential roles of oligosaccharides and glycoconjugates in many important biological recognition processes, including intracellular signaling, cell adhesion, cell differentiation, cancer progression, host-pathogen interactions, and immune responses. A detailed understanding of the biological functions, as well as the development of carbohydrate-based therapeutics, often requires structurally well-defined oligosaccharides and glycoconjugates, which are usually difficult to isolate in pure form from natural sources. To meet with this urgent need, chemical and chemoenzymatic synthesis has become increasingly important as the major means to provide homogeneous compounds for functional glycocomics studies and for drug/vaccine development. Chemoenzymatic synthesis, an approach that combines chemical synthesis and enzymatic manipulations, is often the method of choice for constructing complex oligosaccharides and glycoconjugates that are otherwise difficult to achieve by purely chemical synthesis. Among these, endoglycosidases, a class of glycosidases that hydrolyze internal glycosidic bonds in glycoconjugates and polysaccharides, are emerging as a very attractive class of enzymes for synthetic purposes, due to their transglycosylation activity and their capability of transferring oligosaccharide units en bloc in a single step, in contrast to the limitation of monosaccharide transfers by common glycosyltransferases. In this chapter, we provide an overview on the application of endoglycosidases for the synthesis of complex carbohydrates, including oligosaccharides, polysaccharides, glycoproteins, glycolipids, proteoglycans, and other biologically relevant polysaccharides. The scope, limitation, and future directions of endoglycosidase-catalyzed synthesis are discussed.
Collapse
Affiliation(s)
- Chao Li
- University of Maryland, College Park, MD, United States
| | - Lai-Xi Wang
- University of Maryland, College Park, MD, United States
| |
Collapse
|
13
|
Yamaguchi T, Amin MN, Toonstra C, Wang LX. Chemoenzymatic Synthesis and Receptor Binding of Mannose-6-Phosphate (M6P)-Containing Glycoprotein Ligands Reveal Unusual Structural Requirements for M6P Receptor Recognition. J Am Chem Soc 2016; 138:12472-85. [PMID: 27500601 DOI: 10.1021/jacs.6b05762] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Mannose-6-phosphate (M6P)-terminated oligosaccharides are important signals for M6P-receptor-mediated targeting of newly synthesized hydrolases from Golgi to lysosomes, but the precise structural requirement for the M6P ligand-receptor recognition has not been fully understood due to the difficulties in obtaining homogeneous M6P-containing glycoproteins. We describe here a chemoenzymatic synthesis of homogeneous phosphoglycoproteins carrying natural M6P-containing N-glycans. The method includes the chemical synthesis of glycan oxazolines with varied number and location of the M6P moieties and their transfer to the GlcNAc-protein by an endoglycosynthase to provide homogeneous M6P-containing glycoproteins. Simultaneous attachment of two M6P-oligosaccahrides to a cyclic polypeptide was also accomplished to yield bivalent M6P-glycopeptides. Surface plasmon resonance binding studies reveal that a single M6P moiety located at the low α-1,3-branch of the oligomannose context is sufficient for a high-affinity binding to receptor CI-MPR, while the presence of a M6P moiety at the α-1,6-branch is dispensable. In addition, a binding study with the bivalent cyclic and linear polypeptides reveals that a close proximity of two M6P-oligosaccharide ligands is critical to achieve high affinity for the CI-MPR receptor. Taken together, the present study indicates that the location and valency of the M6P moieties and the right oligosaccharide context are all critical for high-affinity binding with the major M6P receptor. The chemoenzymatic method described here provides a new avenue for glycosylation remodeling of recombinant enzymes to enhance the uptake and delivery of enzymes to lysosomes in enzyme replacement therapy for the treatment of lysosomal storage diseases.
Collapse
Affiliation(s)
- Takahiro Yamaguchi
- Institute of Human Virology, University of Maryland School of Medicine , Baltimore, Maryland 21201, United States
| | - Mohammed N Amin
- Institute of Human Virology, University of Maryland School of Medicine , Baltimore, Maryland 21201, United States.,Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742, United States
| | - Christian Toonstra
- Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742, United States
| | - Lai-Xi Wang
- Institute of Human Virology, University of Maryland School of Medicine , Baltimore, Maryland 21201, United States.,Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742, United States
| |
Collapse
|
14
|
Toonstra C, Amin MN, Wang LX. Site-Selective Chemoenzymatic Glycosylation of an HIV-1 Polypeptide Antigen with Two Distinct N-Glycans via an Orthogonal Protecting Group Strategy. J Org Chem 2016; 81:6176-85. [PMID: 27380452 DOI: 10.1021/acs.joc.6b01044] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A convergent chemoenzymatic approach for sequential installation of different N-glycans in a polypeptide is described. The method includes introduction of distinguishably protected GlcNAc-Asn building blocks during automated solid phase peptide synthesis (SPPS), followed by orthogonal deprotection of the GlcNAc primers and site-selective sequential extension of the sugar chains through glycosynthase-catalyzed transglycosylation reactions. It was observed that the protecting groups on one neighboring GlcNAc moiety have an impact on the substrate activity of another GlcNAc acceptor toward some endoglycosynthases in transglycosylation. The usefulness of this synthetic strategy was exemplified by an efficient synthesis of the glycopeptide neutralizing epitope of broadly HIV-neutralizing antibody PG9. The method should be generally applicable for the synthesis of complex glycopeptides carrying multiple different N-glycans.
Collapse
Affiliation(s)
- Christian Toonstra
- Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742, United States
| | - Mohammed N Amin
- Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742, United States
| | - Lai-Xi Wang
- Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742, United States
| |
Collapse
|
15
|
Giddens JP, Lomino JV, Amin MN, Wang LX. Endo-F3 Glycosynthase Mutants Enable Chemoenzymatic Synthesis of Core-fucosylated Triantennary Complex Type Glycopeptides and Glycoproteins. J Biol Chem 2016; 291:9356-70. [PMID: 26966183 DOI: 10.1074/jbc.m116.721597] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Indexed: 11/06/2022] Open
Abstract
Chemoenzymatic synthesis is emerging as a promising approach to the synthesis of homogeneous glycopeptides and glycoproteins highly demanded for functional glycomics studies, but its generality relies on the availability of a range of enzymes with high catalytic efficiency and well defined substrate specificity. We describe in this paper the discovery of glycosynthase mutants derived from Elizabethkingia meningoseptica endoglycosidase F3 (Endo-F3) of the GH18 family, which are devoid of the inherent hydrolytic activity but are able to take glycan oxazolines for transglycosylation. Notably, the Endo-F3 D165A and D165Q mutants demonstrated high acceptorsubstrate specificity toward α1,6-fucosyl-GlcNAc-Asn or α1,6-fucosyl-GlcNAc-polypeptide in transglycosylation, enabling a highly convergent synthesis of core-fucosylated, complex CD52 glycopeptide antigen. The Endo-F3 mutants were able to use both bi- and triantennary glycan oxazolines as substrates for transglycosylation, in contrast to previously reported endoglycosidases derived from Endo-S, Endo-M, Endo-D, and Endo-A mutants that could not recognize triantennary N-glycans. Using rituximab as a model system, we have further demonstrated that the Endo-F3 mutants are highly efficient for glycosylation remodeling of monoclonal antibodies to produce homogeneous intact antibody glycoforms. Interestingly, the new triantennary glycan glycoform of antibody showed much higher affinity for galectin-3 than that of the commercial antibody. The Endo-F3 mutants represent the first endoglycosidase-based glycosynthases capable of transferring triantennary complex N-glycans, which would be very useful for glycoprotein synthesis and glycosylation remodeling of antibodies.
Collapse
Affiliation(s)
- John P Giddens
- From the Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland 21201 and the Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742
| | - Joseph V Lomino
- From the Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland 21201 and
| | - Mohammed N Amin
- From the Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland 21201 and the Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742
| | - Lai-Xi Wang
- From the Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland 21201 and the Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742
| |
Collapse
|
16
|
Harvey DJ. Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: an update for 2009-2010. MASS SPECTROMETRY REVIEWS 2015; 34:268-422. [PMID: 24863367 PMCID: PMC7168572 DOI: 10.1002/mas.21411] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 07/16/2013] [Accepted: 07/16/2013] [Indexed: 05/07/2023]
Abstract
This review is the sixth update of the original article published in 1999 on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2010. General aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, arrays and fragmentation are covered in the first part of the review and applications to various structural typed constitutes the remainder. The main groups of compound that are discussed in this section are oligo and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Many of these applications are presented in tabular form. Also discussed are medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis.
Collapse
Affiliation(s)
- David J. Harvey
- Department of BiochemistryOxford Glycobiology InstituteUniversity of OxfordOxfordOX1 3QUUK
| |
Collapse
|
17
|
Wang LX, Amin MN. Chemical and chemoenzymatic synthesis of glycoproteins for deciphering functions. ACTA ACUST UNITED AC 2015; 21:51-66. [PMID: 24439206 DOI: 10.1016/j.chembiol.2014.01.001] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 12/31/2013] [Accepted: 01/02/2014] [Indexed: 12/11/2022]
Abstract
Glycoproteins are an important class of biomolecules involved in a number of biological recognition processes. However, natural and recombinant glycoproteins are usually produced as mixtures of glycoforms that differ in the structures of the pendent glycans, which are difficult to separate in pure glycoforms. As a result, synthetic homogeneous glycopeptides and glycoproteins have become indispensable probes for detailed structural and functional studies. A number of elegant chemical and biological strategies have been developed for synthetic construction of tailor-made, full-size glycoproteins to address specific biological problems. In this review, we highlight recent advances in chemical and chemoenzymatic synthesis of homogeneous glycoproteins. Selected examples are given to demonstrate the applications of tailor-made, glycan-defined glycoproteins for deciphering glycosylation functions.
Collapse
Affiliation(s)
- Lai-Xi Wang
- Institute of Human Virology and Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Mohammed N Amin
- Institute of Human Virology and Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| |
Collapse
|
18
|
A simplified procedure for gram-scale production of sialylglycopeptide (SGP) from egg yolks and subsequent semi-synthesis of Man3GlcNAc oxazoline. Carbohydr Res 2014; 396:62-9. [DOI: 10.1016/j.carres.2014.07.013] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 07/16/2014] [Accepted: 07/18/2014] [Indexed: 01/19/2023]
|
19
|
Abstract
The synthetic application of endohexosaminidase enzymes (e.g., Endo A, Endo M, Endo D) promises to allow ready access to a wide variety of defined homogeneous glycoproteins and glycopeptides. The use ofN-glycan oligosaccharides that are activated at the reducing terminus as oxazolines allows their high-yielding attachment to almost any amino acid, peptide, or protein that contains a GlcNAc residue as an acceptor. A wide variety of oxazoline donors are readily available, either by total synthesis or by isolation of the corresponding oligosaccharide from natural sources and then conversion to the oxazoline in water. The synthetic potential of the enzymes is particularly augmented by the production of mutant glycosynthases, the use of which allows the synthesis of a wide variety of glycopeptides and glycoproteins bearing defined homogeneousN-glycan structures.
Collapse
|
20
|
Synthetic glycopeptides reveal the glycan specificity of HIV-neutralizing antibodies. Nat Chem Biol 2013; 9:521-6. [PMID: 23831758 PMCID: PMC3730851 DOI: 10.1038/nchembio.1288] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Accepted: 05/30/2013] [Indexed: 12/31/2022]
Abstract
A new class of glycan-reactive HIV-neutralizing antibodies, including PG9 and PG16, has been recently discovered that appear to recognize novel glycopeptide epitopes on HIV-1 gp120. However, further characterization and reconstitution of the precise neutralizing epitopes are complicated by the heterogeneity of glycosylation. We report here the design, synthesis, and antigenic evaluation of novel cyclic V1V2 glycopeptides carrying defined N-linked glycans at the conserved glycosylation sites (N160 and N156/N173) derived from gp120 of two HIV-1 isolates. Antibody binding studies confirmed the necessity of a Man5GlcNAc2 glycan at N160 for recognition by PG9 and PG16, and further revealed a critical role of a sialylated N-glycan at the secondary site (N156/N173) in the context of glycopeptides for antibody binding. In addition to defining the glycan specificities of PG9 and PG16, the identified synthetic glycopeptides provide a valuable template for HIV-1 vaccine design.
Collapse
|
21
|
Recent advances in glycotechnology for glycoconjugate synthesis using microbial endoglycosidases. Biotechnol Lett 2013; 35:1733-43. [PMID: 23801123 DOI: 10.1007/s10529-013-1272-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2013] [Accepted: 06/11/2013] [Indexed: 01/10/2023]
Abstract
Biotechnology associated with synthesis of glycopeptides and glycoproteins has recently advanced as glycotechnology. Studies toward glycotechonology include the artificial modification of sugar chains in glycoconjugates to improve their function because the physiological importance of sugar chains in living organisms is well recognized. Methods involving addition of oligosaccharides to peptides and proteins have attracted attention as efficient techniques in glycotechnology, especially those involving the transglycosylation activities of microbial endoglycosidases. The exploration of oligosaccharide oxazolines as donor substrates for the transglycosylation of endoglycosidases has significantly enhanced the efficiency of these processes. Moreover, discovery of novel endoglycosidase mutants with glycosynthase-like activity has made it possible to effectively synthesize large quantities of glycopeptides, as well as homogeneous glycoprotein. The use of mutant enzymes and oligosaccharide oxazolines has led to development of practical applications for the synthesis of bioactive glycopeptides and therapeutic glycoproteins as bio-medicines.
Collapse
|
22
|
Lomino JV, Naegeli A, Orwenyo J, Amin MN, Aebi M, Wang LX. A two-step enzymatic glycosylation of polypeptides with complex N-glycans. Bioorg Med Chem 2013; 21:2262-2270. [PMID: 23477942 DOI: 10.1016/j.bmc.2013.02.007] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 02/02/2013] [Accepted: 02/11/2013] [Indexed: 11/30/2022]
Abstract
A chemoenyzmatic method for direct glycosylation of polypeptides is described. The method consists of two site-specific enzymatic glycosylation steps: introduction of a glucose moiety at the consensus N-glycosylation sequence (NXS/T) in a polypeptide by an N-glycosyltransferase (NGT) and attachment of a complex N-glycan to the glucose primer by an endoglycosidase (ENGase)-catalyzed transglycosylation. Our experiments demonstrated that a relatively small excess of the UDP-Glc (the donor substrate) was sufficient for an effective glucosylation of polypeptides by the NGT, and different high-mannose and complex type N-glycans could be readily transferred to the glucose moiety by ENGases to provide full-size glycopeptides. The usefulness of the chemoenzymatic method was exemplified by an efficient synthesis of a complex glycoform of polypeptide C34, a potent HIV inhibitor derived from HIV-1 gp41. A comparative study indicated that the Glc-peptide was equally efficient as the natural GlcNAc-peptide to serve as an acceptor in the transglycosylation with sugar oxazoline as the donor substrate. Interestingly, the Glc-Asn linked glycopeptide was completely resistant to PNGase F digestion, in contrast to the GlcNAc-Asn linked natural glycopeptide that is an excellent substrate for hydrolysis. In addition, the Glc-Asn linked glycopeptide showed at least 10-fold lower hydrolytic activity toward Endo-M than the natural GlcNAc-Asn linked glycopeptide. The chemoenzymatic glycosylation method described here provides an efficient way to introducing complex N-glycans into polypeptides, for gain of novel properties that could be valuable for drug discovery.
Collapse
Affiliation(s)
- Joseph V Lomino
- Institute of Human Virology and Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, United States
| | - Andreas Naegeli
- Institute of Microbiology, Dept. of Biology, ETH Zürich, Wolfgang-Pauli-Str. 10, 8093 Zürich, Switzerland
| | - Jared Orwenyo
- Institute of Human Virology and Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, United States
| | - Mohammed N Amin
- Institute of Human Virology and Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, United States
| | - Markus Aebi
- Institute of Microbiology, Dept. of Biology, ETH Zürich, Wolfgang-Pauli-Str. 10, 8093 Zürich, Switzerland
| | - Lai-Xi Wang
- Institute of Human Virology and Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, United States.
| |
Collapse
|
23
|
Wang LX, Lomino JV. Emerging technologies for making glycan-defined glycoproteins. ACS Chem Biol 2012; 7:110-22. [PMID: 22141574 DOI: 10.1021/cb200429n] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Protein glycosylation is a common and complex posttranslational modification of proteins, which expands functional diversity while boosting structural heterogeneity. Glycoproteins, the end products of such a modification, are typically produced as mixtures of glycoforms possessing the same polypeptide backbone but differing in the site of glycosylation and/or in the structures of pendant glycans, from which single glycoforms are difficult to isolate. The urgent need for glycan-defined glycoproteins in both detailed structure-function relationship studies and therapeutic applications has stimulated an extensive interest in developing various methods for manipulating protein glycosylation. This review highlights emerging technologies that hold great promise in making a variety of glycan-defined glycoproteins, with a particular emphasis in the following three areas: specific glycoengineering of host biosynthetic pathways, in vitro chemoenzymatic glycosylation remodeling, and chemoselective and site-specific glycosylation of proteins.
Collapse
Affiliation(s)
- Lai-Xi Wang
- Institute of Human Virology and Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201, United States
| | - Joseph V. Lomino
- Institute of Human Virology and Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201, United States
| |
Collapse
|
24
|
Cobucci-Ponzano B, Moracci M. Glycosynthases as tools for the production of glycan analogs of natural products. Nat Prod Rep 2012; 29:697-709. [DOI: 10.1039/c2np20032e] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
25
|
Zou G, Ochiai H, Huang W, Yang Q, Li C, Wang LX. Chemoenzymatic synthesis and Fcγ receptor binding of homogeneous glycoforms of antibody Fc domain. Presence of a bisecting sugar moiety enhances the affinity of Fc to FcγIIIa receptor. J Am Chem Soc 2011; 133:18975-91. [PMID: 22004528 DOI: 10.1021/ja208390n] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Structurally well-defined IgG-Fc glycoforms are highly demanded for understanding the effects of glycosylation on an antibody's effector functions. We report in this paper chemoenzymatic synthesis and Fcγ receptor binding of an array of homogeneous IgG-Fc glycoforms. The chemoenzymatic approach consists of the chemical synthesis of defined N-glycan oxazolines as donor substrates, the expression of the Fc domain in a CHO cell line in the presence of an α-mannosidase inhibitor kifunensine, and an endoglycosidase-catalyzed glycosylation of the deglycosylated Fc domain (GlcNAc-Fc homodimer) with the synthetic glycan oxazolines. The enzyme from Arthrobacter protophormiae (Endo-A) was found to be remarkably efficient to take various modified N-glycan core oxazolines, including the bisecting sugar-containing derivatives, for Fc glycosylation remodeling, resulting in the formation of the corresponding homogeneous Fc glycoforms. Nevertheless, neither Endo-A nor the Mucor hiemalis endoglycosidase mutants (EndoM-N175A and EndoM-N175Q) were able to transfer full-length complex-type N-glycan to the Fc domain, implicating the limitations of these two enzymes in Fc glycosylation remodeling. Surface plasmon resonance (SPR) binding studies with the synthetic IgG-Fc glycoforms unambiguously proved that the presence of a bisecting GlcNAc moiety could significantly enhance the binding of Fc to FcγRIIIa, the activating Fcγ receptor, independent of Fc core-fucosylation. Interestingly, the Fc glycoforms carrying an unusual bisecting sugar moiety such as a mannose or a LacNAc moiety also demonstrated enhanced affinity to FcγRIIIa. On the orther hand, the presence of a bisecting GlcNAc or core-fucosylation had little effect on the affinity of Fc to the inhibitory Fcγ receptor, FcγRIIb. Our experimental data also showed that the α-linked mannose residues in the pentasaccharide Man3GlcNAc2 core was essential to maintain a high affinity of Fc to both FcγRIIIa and FcγRIIb. The synthetic homogeneous Fc glycoforms thus provide a useful tool for elucidating how a fine Fc N-glycan structure precisely affects the function of the Fc domain.
Collapse
Affiliation(s)
- Guozhang Zou
- Institute of Human Virology and Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
| | | | | | | | | | | |
Collapse
|
26
|
Amin MN, Huang W, Mizanur RM, Wang LX. Convergent synthesis of homogeneous Glc1Man9GlcNAc2-protein and derivatives as ligands of molecular chaperones in protein quality control. J Am Chem Soc 2011; 133:14404-17. [PMID: 21819116 DOI: 10.1021/ja204831z] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A detailed understanding of the molecular mechanism of chaperone-assisted protein quality control is often hampered by the lack of well-defined homogeneous glycoprotein probes. We describe here a highly convergent chemoenzymatic synthesis of the monoglucosylated glycoforms of bovine ribonuclease (RNase) as specific ligands of lectin-like chaperones calnexin (CNX) and calreticulin (CRT) that are known to recognize the monoglucosylated high-mannose oligosaccharide component of glycoproteins in protein folding. The synthesis of a selectively modified glycoform Gal(1)Glc(1)Man(9)GlcNAc(2)-RNase was accomplished by chemical synthesis of a large N-glycan oxazoline and its subsequent enzymatic ligation to GlcNAc-RNase under the catalysis of a glycosynthase. Selective removal of the terminal galactose by a β-galactosidase gave the Glc(1)Man(9)GlcNAc(2)-RNase glycoform in excellent yield. CD spectroscopic analysis and RNA-hydrolyzing assay indicated that the synthetic RNase glycoforms maintained essentially the same global conformations and were fully active as the natural bovine ribonuclease B. SPR binding studies revealed that the Glc(1)Man(9)GlcNAc(2)-RNase had high affinity to lectin CRT, while the synthetic Man(9)GlcNAc(2)-RNase glycoform and natural RNase B did not show CRT-binding activity. These results confirmed the essential role of the glucose moiety in the chaperone molecular recognition. Interestingly, the galactose-masked glycoform Gal(1)Glc(1)Man(9)GlcNAc(2)-RNase also showed significant affinity to lectin CRT, suggesting that a galactose β-1,4-linked to the key glucose moiety does not significantly block the lectin binding. These synthetic homogeneous glycoprotein probes should be valuable for a detailed mechanistic study on how molecular chaperones work in concert to distinguish between misfolded and folded glycoproteins in the protein quality control cycle.
Collapse
Affiliation(s)
- Mohammed N Amin
- Institute of Human Virology, Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
| | | | | | | |
Collapse
|
27
|
Huang W, Li J, Wang LX. Unusual transglycosylation activity of Flavobacterium meningosepticum endoglycosidases enables convergent chemoenzymatic synthesis of core fucosylated complex N-glycopeptides. Chembiochem 2011; 12:932-41. [PMID: 21374780 DOI: 10.1002/cbic.201000763] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Indexed: 11/05/2022]
Abstract
Structurally well defined, homogeneous glycopeptides and glycoproteins are indispensable tools for functional glycomics studies. By screening of various endo-β-N-acetylglucosaminidases through the use of appropriate synthetic donor and acceptor substrates, we have found that the Flavobacterium meningosepticum endo-β-N-acetyl-glucosaminidases (GH family 18), including Endo-F2 and Endo-F3, were able to glycosylate α-1,6-fucosylated GlcNAc derivative to provide natural, core-fucosylated complex-type N-glycopeptides. The Endo-F2 and Endo-F3 were efficient for transferring both sialylated and asia-lylated glycans and were highly specific for an α-1,6-fucosylated GlcNAc-peptide as acceptor for transglycosylation, showing only marginal activity with non-fucosylated GlcNAc-peptides. In contrast, we found that the commonly used endoglycosidases such as Endo-A and Endo-M, which belong to GH family 85, were unable to take α-1,6-fucosyl-GlcNAc derivative as acceptors for transglycosylation. The novel activity of Endo-F2 and Endo-F3 was successfully applied for a highly convergent chemoenzymatic synthesis of a full-sized CD52 glycopeptide antigen carrying both terminal sialic acid and core fucose. This is the first report on endoglycosidases that are able to glycosylate α-1,6-fucosylated GlcNAc derivatives to form natural core-fucosylated glycopeptides.
Collapse
Affiliation(s)
- Wei Huang
- Institute of Human Virology and Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201 (USA), Fax: (+1) 410-706-4694
| | | | | |
Collapse
|
28
|
Wang LX. The Amazing Transglycosylation Activity of Endo-β-N-acetylglucosaminidases. TRENDS GLYCOSCI GLYC 2011; 23:33-52. [PMID: 25309039 DOI: 10.4052/tigg.23.33] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Major advances have been made in exploring the transglycosylation activity of endo-β-N-acetylglucosaminidases (ENGases) for synthetic purpose. The exploration of synthetic sugar oxazolines as donor substrates for the ENGase-catalyzed transglycosylation has expanded the substrate availability and significantly enhanced the overall transglycosylation efficiency. On the other hand, site-directed mutagenesis in combination with activity screening has led to the discovery of the first generation ENGase-based glycosynthases that can use highly active sugar oxazolines as substrates for transglycosylation but lack hydrolytic activity on the ground-state products. ENGases have shown amazing flexibility in transglycosylation and possess much broader substrate specificity than previously thought. Now the ENGase-based chemoenzymatic method has been extended to the synthesis of a range of complex carbohydrates, including homogeneous glycopeptides, glycoproteins carrying well-defined glycans, novel oligosaccharide clusters, unusually glycosylated natural products, and even polysaccharides. This article highlights recent advances related to ENGase-catalyzed transglycosylation with a focus on their synthetic potential.
Collapse
Affiliation(s)
- Lai-Xi Wang
- Institute of Human Virology and Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA, Tel: 410-706-4982
| |
Collapse
|