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Wagner-Rousset E, Colas O, Chenu S, François YN, Guillarme D, Cianferani S, Tsybin YO, Sjögren J, Delobel A, Beck A. Fast Afucosylation Profiling of Glycoengineered Antibody Subunits by Middle-Up Mass Spectrometry. Methods Mol Biol 2021; 2271:73-83. [PMID: 33908000 DOI: 10.1007/978-1-0716-1241-5_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Middle-up LC-MS antibody characterization workflows using reduction or IdeS digestion for a focused assessment of N-glycan profiling of three representative glycoengineered monoclonal antibodies (mAbs), namely, obinutuzumab (GlycomAb technology, Glycart/Roche), benralizumab (Potelligent Technology, BioWa, Kyowa Kirin) and mAb B (kifunensine) and compared to mAb A, produced in a common CHO cell line. In addition, EndoS or EndoS2 enzyme are used for quantitative determination of Fc-glycan core afucosylation and high mannose for these antibodies, as requested by health authorities for Fc-competent therapeutics mAbs critical quality attributes (CQAs).
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Affiliation(s)
- Elsa Wagner-Rousset
- Pierre Fabre Laboratories, IRPF-Centre d'Immunologie Pierre-Fabre (CIPF), Saint-Julien-en-Genevois, France
| | - Olivier Colas
- Pierre Fabre Laboratories, IRPF-Centre d'Immunologie Pierre-Fabre (CIPF), Saint-Julien-en-Genevois, France
| | - Stéphane Chenu
- Pierre Fabre Laboratories, IRPF-Centre d'Immunologie Pierre-Fabre (CIPF), Saint-Julien-en-Genevois, France
| | - Yannis-Nicolas François
- Laboratoire de Spectrométrie de Masse des Interactions et des Systèmes (LSMIS), UMR 7140, Université de Strasbourg, CNRS, Strasbourg, France
| | - Davy Guillarme
- School of Pharmaceutical Sciences, University of Geneva, CMU, Geneva, Switzerland
- Institute of Pharmaceutical Sciences of Western Switzerland (ISPSO), University of Geneva, CMU, Geneva, Switzerland
| | - Sarah Cianferani
- Laboratoire de Spectrométrie de Masse BioOrganique, IPHC UMR 7178, Université de Strasbourg, CNRS, Strasbourg, France
| | - Yury O Tsybin
- Spectroswiss Sarl, EPFL Innovation Park, Lausanne, Switzerland
| | | | | | - Alain Beck
- Pierre Fabre Laboratories, IRPF-Centre d'Immunologie Pierre-Fabre (CIPF), Saint-Julien-en-Genevois, France.
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2
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Mozziconacci O, Subelzu N, Schöneich C, Liu Y, Abend A, Wuelfing WP. Probing Protein Conformation Destabilization in Sterile Liquid Formulations through the Formation of 3,4-Dihydroxyphenylalanine. Mol Pharm 2020; 17:3783-3793. [PMID: 32910663 DOI: 10.1021/acs.molpharmaceut.0c00554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This work demonstrates the use of a fluorescent probe to screen protein conformational changes in mixtures of monoclonal antibodies and determine the region of where such changes may originate through a footprinting mass spectrometry approach. The oxidative stress of mixtures of two different immunoglobulins (IgG1, IgG2, or IgG4) performed in the presence of 2,2'-azobis(2-amidinopropane dihydrochloride) results in sequence-specific tyrosine oxidation reactions depending on the time of incubation of the IgG molecules and the nature of the excipients present in the formulation. The combination of a fluorescence assay, based on the detection of 3,4-dihydroxyphenylalanine (DOPA) and mass spectrometry analyses, permits the identification of protein conformation changes. In a mixture of IgG2 and IgG4, a destabilization of IgG4 in the presence of IgG2 is observed. The destabilized region involves the Fab region of IgG4 between Tyr63 and Tyr81 and potentially multiple regions of IgG2.
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Affiliation(s)
| | - Natalia Subelzu
- Department of Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas 66047, United States
| | - Christian Schöneich
- Department of Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas 66047, United States
| | - Yong Liu
- Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Andreas Abend
- Merck & Co., Inc., Rahway, New Jersey 07065, United States
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3
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Lim S, Kim DS, Ko K. Expression of a Large Single-Chain 13F6 Antibody with Binding Activity against Ebola Virus-Like Particles in a Plant System. Int J Mol Sci 2020; 21:E7007. [PMID: 32977599 PMCID: PMC7582593 DOI: 10.3390/ijms21197007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 09/17/2020] [Accepted: 09/20/2020] [Indexed: 11/16/2022] Open
Abstract
Pathogenic animal and human viruses present a growing and persistent threat to humans worldwide. Ebola virus (EBOV) causes zoonosis in humans. Here, two structurally different anti-Ebola 13F6 antibodies, recognizing the heavily glycosylated mucin-like domain (MLD) of the glycoprotein (GP), were expressed in transgenic Nicotiana tabacum plants and designed as inexpensive and effective diagnostic antibodies against Ebola virus disease (EVD). The first was anti-EBOV 13F6 full size antibody with heavy chain (HC) and light chain (LC) (monoclonal antibody, mAb 13F6-FULL), while the second was a large single-chain (LSC) antibody (mAb 13F6-LSC). mAb 13F6-LSC was constructed by linking the 13F6 LC variable region (VL) with the HC of mAb 13F6-FULL using a peptide linker and extended to the C-terminus using the endoplasmic reticulum (ER) retention motif KDEL. Agrobacterium-mediated plant transformation was employed to express the antibodies in N. tabacum. PCR, RT-PCR, and immunoblot analyses confirmed the gene insertion, transcription, and protein expression of these antibodies, respectively. The antibodies tagged with the KDEL motif displayed high-mannose type N-glycan structures and efficient binding to EBOV-like particles (VLPs). Thus, various forms of anti-EBOV plant-derived mAbs 13F6-FULL and LSC with efficient binding affinity to EBOV VLP can be produced in the plant system.
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Affiliation(s)
- Sohee Lim
- Department of Medicine, College of Medicine, Chung-Ang University, Seoul 06974, Korea;
| | - Do-Sun Kim
- Vegetable Research Division, National Institute of Horticultural and Herbal Science, Rural Development Administration, Jeonju 55365, Korea;
| | - Kisung Ko
- Department of Medicine, College of Medicine, Chung-Ang University, Seoul 06974, Korea;
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4
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Chromatographic assay to probe the binding energy and mechanisms of homologous proteins to surface-bound ligands. J Chromatogr B Analyt Technol Biomed Life Sci 2020; 1136:121927. [DOI: 10.1016/j.jchromb.2019.121927] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 10/08/2019] [Accepted: 12/03/2019] [Indexed: 01/01/2023]
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5
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Bas M, Terrier A, Jacque E, Dehenne A, Pochet-Béghin V, Beghin C, Dezetter AS, Dupont G, Engrand A, Beaufils B, Mondon P, Fournier N, de Romeuf C, Jorieux S, Fontayne A, Mars LT, Monnet C. Fc Sialylation Prolongs Serum Half-Life of Therapeutic Antibodies. THE JOURNAL OF IMMUNOLOGY 2019; 202:1582-1594. [PMID: 30683704 DOI: 10.4049/jimmunol.1800896] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 12/29/2018] [Indexed: 01/01/2023]
Abstract
The long serum t 1/2 of IgGs is ensured by their interaction with the neonatal Fc receptor (FcRn), which salvages IgG from intracellular degradation. Fc glycosylation is thought not to influence FcRn binding and IgG longevity in vivo. In this article, we demonstrate that hypersialylation of asparagine 297 (N297) enhances IgG serum persistence. This polarized glycosylation is achieved using a novel Fc mutation, a glutamate residue deletion at position 294 (Del) that endows IgGs with an up to 9-fold increase in serum lifespan. The strongest impact was observed when the Del was combined with Fc mutations improving FcRn binding (Del-FcRn+). Enzymatic desialylation of a Del-FcRn+ mutant or its production in a cell line unable to hypersialylate reduced the in vivo serum t 1/2 of the desialylated mutants to that of native FcRn+ mutants. Consequently, our study proves that sialylation of the N297 sugar moiety has a direct impact on human IgG serum persistence.
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Affiliation(s)
- Mathilde Bas
- LFB Biotechnologies, 59011 Lille Cedex, France.,INSERM UMR995, Laboratory of Neuroinflammation and Multiple Sclerosis, F-59000 Lille, France.,University of Lille, Lille Center of Excellence in Neurodegenerative Diseases (LICEND), F-59000 Lille, France; and
| | | | - Emilie Jacque
- LFB Biotechnologies, 91958 Courtaboeuf Cedex, France
| | | | | | | | | | | | | | | | | | | | | | | | | | - Lennart T Mars
- INSERM UMR995, Laboratory of Neuroinflammation and Multiple Sclerosis, F-59000 Lille, France.,University of Lille, Lille Center of Excellence in Neurodegenerative Diseases (LICEND), F-59000 Lille, France; and
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6
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Yageta S, Imamura H, Shibuya R, Honda S. C H2 domain orientation of human immunoglobulin G in solution: Structural comparison of glycosylated and aglycosylated Fc regions using small-angle X-ray scattering. MAbs 2018; 11:453-462. [PMID: 30513259 PMCID: PMC6512918 DOI: 10.1080/19420862.2018.1546086] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The N-linked glycan in immunoglobulin G is critical for the stability and function of the crystallizable fragment (Fc) region. Alteration of these protein properties upon the removal of the N-linked glycan has often been explained by the alteration of the CH2 domain orientation in the Fc region. To confirm this hypothesis, we examined the small-angle X-ray scattering (SAXS) profile of the glycosylated Fc region (gFc) and aglycosylated Fc region (aFc) in solution. Conformational characteristics of the CH2 domain orientation were validated by comparison with SAXS profiles theoretically calculated from multiple crystal structures of the Fc region with different CH2 domain orientations. The reduced chi-square values from the fitting analyses of gFc and aFc associated with the degree of openness or closure of each crystal structure, as determined from the first principal component that partially governed the variation of the CH2 domain orientation extracted by a singular value decomposition analysis. For both gFc and aFc, the best-fitted SAXS profiles corresponded to ones calculated based on the crystal structure of gFc that formed a "semi-closed" CH2 domain orientation. Collectively, the data indicated that the removal of the N-linked glycan only negligibly affected the CH2 domain orientation in solution. These findings will guide the development of methodology for the production of highly refined functional Fc variants.
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Affiliation(s)
- Seiki Yageta
- a Biomedical Research Institute , National Institute of Advanced Industrial Science and Technology (AIST) , Tsukuba, Ibaraki , Japan.,b Department of Computational Biology and Medical Sciences , Graduate School of Frontier Sciences, the University of Tokyo , Kashiwa , Chiba , Japan.,c Manufacturing Technology Association of Biologics , Tsukuba , Ibaraki , Japan
| | - Hiroshi Imamura
- a Biomedical Research Institute , National Institute of Advanced Industrial Science and Technology (AIST) , Tsukuba, Ibaraki , Japan.,d Department of Applied Chemistry , College of Life Sciences, Ritsumeikan University , Kusatsu , Shiga , Japan
| | - Risa Shibuya
- b Department of Computational Biology and Medical Sciences , Graduate School of Frontier Sciences, the University of Tokyo , Kashiwa , Chiba , Japan
| | - Shinya Honda
- a Biomedical Research Institute , National Institute of Advanced Industrial Science and Technology (AIST) , Tsukuba, Ibaraki , Japan.,b Department of Computational Biology and Medical Sciences , Graduate School of Frontier Sciences, the University of Tokyo , Kashiwa , Chiba , Japan.,c Manufacturing Technology Association of Biologics , Tsukuba , Ibaraki , Japan
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7
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Gupta SK, Shukla P. Glycosylation control technologies for recombinant therapeutic proteins. Appl Microbiol Biotechnol 2018; 102:10457-10468. [DOI: 10.1007/s00253-018-9430-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 10/02/2018] [Accepted: 10/02/2018] [Indexed: 12/12/2022]
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8
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Remesh SG, Armstrong AA, Mahan AD, Luo J, Hammel M. Conformational Plasticity of the Immunoglobulin Fc Domain in Solution. Structure 2018; 26:1007-1014.e2. [PMID: 29731233 DOI: 10.1016/j.str.2018.03.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 03/07/2018] [Accepted: 03/27/2018] [Indexed: 12/21/2022]
Abstract
Fragment crystallizable (Fc) region of immunoglobulin G (IgG) antibody binds to specific Fc receptors (FcγRs) to control antibody effector functions. Currently, engineered specific Fc-FcγR interactions are validated with a static conformation derived from the crystal structure. However, computational evidence suggests that the conformational variability of Fcs plays an important role in receptor recognition. Here we elucidate Fc flexibility of IgG1, IgG2, and IgG1 Fc with mutations (M255Y/S257T/T259E) in solution by small-angle X-ray scattering (SAXS). Measured SAXS profiles and experimental parameters show variations in flexibility between Fc isotypes. We develop and apply a modeling tool for an accurate conformational sampling of Fcs followed by SAXS fitting. Revealed conformational variability of the CH2 domain as low as 10 Å in displacement, illustrates the power of the atomistic modeling combined with SAXS. This inexpensive SAXS-based approach offers to improve the engineering of antibodies for tailoring Fc receptor interactions through altering and measuring Fc flexibility.
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Affiliation(s)
- Soumya G Remesh
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | | | - Andrew D Mahan
- Janssen BioTherapeutics, Janssen R&D, LLC, Spring House, PA 19477, USA
| | - Jinquan Luo
- Janssen BioTherapeutics, Janssen R&D, LLC, Spring House, PA 19477, USA.
| | - Michal Hammel
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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9
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Emsley P, Crispin M. Structural analysis of glycoproteins: building N-linked glycans with Coot. Acta Crystallogr D Struct Biol 2018; 74:256-263. [PMID: 29652253 PMCID: PMC5892875 DOI: 10.1107/s2059798318005119] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 03/29/2018] [Indexed: 12/22/2022] Open
Abstract
Coot is a graphics application that is used to build or manipulate macromolecular models; its particular forte is manipulation of the model at the residue level. The model-building tools of Coot have been combined and extended to assist or automate the building of N-linked glycans. The model is built by the addition of monosaccharides, placed by variation of internal coordinates. The subsequent model is refined by real-space refinement, which is stabilized with modified and additional restraints. It is hoped that these enhanced building tools will help to reduce building errors of N-linked glycans and improve our knowledge of the structures of glycoproteins.
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Affiliation(s)
- Paul Emsley
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, England
| | - Max Crispin
- Centre for Biological Sciences and the Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, England
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10
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Structural Transitions of the Conserved and Metastable Hantaviral Glycoprotein Envelope. J Virol 2017; 91:JVI.00378-17. [PMID: 28835498 PMCID: PMC5640846 DOI: 10.1128/jvi.00378-17] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 08/10/2017] [Indexed: 01/13/2023] Open
Abstract
Hantaviruses are zoonotic pathogens that cause severe hemorrhagic fever and pulmonary syndrome. The outer membrane of the hantavirus envelope displays a lattice of two glycoproteins, Gn and Gc, which orchestrate host cell recognition and entry. Here, we describe the crystal structure of the Gn glycoprotein ectodomain from the Asiatic Hantaan virus (HTNV), the most prevalent pathogenic hantavirus. Structural overlay analysis reveals that the HTNV Gn fold is highly similar to the Gn of Puumala virus (PUUV), a genetically and geographically distinct and less pathogenic hantavirus found predominantly in northeastern Europe, confirming that the hantaviral Gn fold is architecturally conserved across hantavirus clades. Interestingly, HTNV Gn crystallized at acidic pH, in a compact tetrameric configuration distinct from the organization at neutral pH. Analysis of the Gn, both in solution and in the context of the virion, confirms the pH-sensitive oligomeric nature of the glycoprotein, indicating that the hantaviral Gn undergoes structural transitions during host cell entry. These data allow us to present a structural model for how acidification during endocytic uptake of the virus triggers the dissociation of the metastable Gn-Gc lattice to enable insertion of the Gc-resident hydrophobic fusion loops into the host cell membrane. Together, these data reveal the dynamic plasticity of the structurally conserved hantaviral surface. IMPORTANCE Although outbreaks of Korean hemorrhagic fever were first recognized during the Korean War (1950 to 1953), it was not until 1978 that they were found to be caused by Hantaan virus (HTNV), the most prevalent pathogenic hantavirus. Here, we describe the crystal structure of HTNV envelope glycoprotein Gn, an integral component of the Gn-Gc glycoprotein spike complex responsible for host cell entry. HTNV Gn is structurally conserved with the Gn of a genetically and geographically distal hantavirus, Puumala virus, indicating that the observed α/β fold is well preserved across the Hantaviridae family. The combination of our crystal structure with solution state analysis of recombinant protein and electron cryo-microscopy of acidified hantavirus allows us to propose a model for endosome-induced reorganization of the hantaviral glycoprotein lattice. This provides a molecular-level rationale for the exposure of the hydrophobic fusion loops on the Gc, a process required for fusion of viral and cellular membranes.
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11
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Shah IS, Lovell S, Mehzabeen N, Battaile KP, Tolbert TJ. Structural characterization of the Man5 glycoform of human IgG3 Fc. Mol Immunol 2017; 92:28-37. [PMID: 29031045 DOI: 10.1016/j.molimm.2017.10.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 09/23/2017] [Accepted: 10/02/2017] [Indexed: 11/15/2022]
Abstract
Immunoglobulin G (IgG) consists of four subclasses in humans: IgG1, IgG2, IgG3 and IgG4, which are highly conserved but have unique differences that result in subclass-specific effector functions. Though IgG1 is the most extensively studied IgG subclass, study of other subclasses is important to understand overall immune function and for development of new therapeutics. When compared to IgG1, IgG3 exhibits a similar binding profile to Fcγ receptors and stronger activation of complement. All IgG subclasses are glycosylated at N297, which is required for Fcγ receptor and C1q complement binding as well as maintaining optimal Fc conformation. We have determined the crystal structure of homogenously glycosylated human IgG3 Fc with a GlcNAc2Man5 (Man5) high mannose glycoform at 1.8Å resolution and compared its structural features with published structures from the other IgG subclasses. Although the overall structure of IgG3 Fc is similar to that of other subclasses, some structural perturbations based on sequence differences were revealed. For instance, the presence of R435 in IgG3 (and H435 in the other IgG subclasses) has been implicated to result in IgG3-specific properties related to binding to protein A, protein G and the neonatal Fc receptor (FcRn). The IgG3 Fc structure helps to explain some of these differences. Additionally, protein-glycan contacts observed in the crystal structure appear to correlate with IgG3 affinity for Fcγ receptors as shown by binding studies with IgG3 Fc glycoforms. Finally, this IgG3 Fc structure provides a template for further studies aimed at engineering the Fc for specific gain of function.
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Affiliation(s)
- Ishan S Shah
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, USA
| | - Scott Lovell
- Protein Structure Laboratory, Del Shankel Structural Biology Center, University of Kansas, Lawrence, KS, USA
| | - Nurjahan Mehzabeen
- Protein Structure Laboratory, Del Shankel Structural Biology Center, University of Kansas, Lawrence, KS, USA
| | - Kevin P Battaile
- IMCA-CAT, Hauptman-Woodward Medical Research Institute, Argonne, IL, USA
| | - Thomas J Tolbert
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, USA.
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12
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Struwe WB, Stuckmann A, Behrens AJ, Pagel K, Crispin M. Global N-Glycan Site Occupancy of HIV-1 gp120 by Metabolic Engineering and High-Resolution Intact Mass Spectrometry. ACS Chem Biol 2017; 12:357-361. [PMID: 27984693 DOI: 10.1021/acschembio.6b00854] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A vital step in HIV vaccine development strategies has been the observation that some infected individuals generate broadly neutralizing antibodies that target the glycans on the surface of HIV-1 gp120. These antibodies target glycan epitopes on viral envelope spikes, and yet the positions and degree of occupancy of glycosylation sites is diverse. Therefore, there is a need to understand glycosylation occupancy on recombinant immunogens. The sheer number of potential glycosylation sites and degree of chemical heterogeneity impedes assessing the global sequon occupancy of gp120 glycoforms. Here, we trap the glycan processing of recombinant gp120 to generate homogeneous glycoforms, facilitating occupancy assessment by intact mass spectrometry. We show that gp120 monomers of the BG505 strain contain either fully occupied sequons or missing the equivalent of one and sometimes two glycans across the molecule. This biosynthetic engineering approach enables the analysis of therapeutically important glycoproteins otherwise recalcitrant to analysis by native mass spectrometry.
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Affiliation(s)
- Weston B. Struwe
- Oxford
Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, United Kingdom
| | - Alexandra Stuckmann
- Free University Berlin, Department of Chemistry
and Biochemistry, Takustrasse
3, 14195 Berlin, Germany
| | - Anna-Janina Behrens
- Oxford
Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, United Kingdom
| | - Kevin Pagel
- Free University Berlin, Department of Chemistry
and Biochemistry, Takustrasse
3, 14195 Berlin, Germany
| | - Max Crispin
- Oxford
Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, United Kingdom
- Department
of Immunology and Microbial Science, The Scripps Research Institute, La
Jolla, California 92037, United States
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13
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Calow J, Behrens AJ, Mader S, Bockau U, Struwe WB, Harvey DJ, Cormann KU, Nowaczyk MM, Loser K, Schinor D, Hartmann MWW, Crispin M. Antibody production using a ciliate generates unusual antibody glycoforms displaying enhanced cell-killing activity. MAbs 2016; 8:1498-1511. [PMID: 27594301 PMCID: PMC5098438 DOI: 10.1080/19420862.2016.1228504] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Antibody glycosylation is a key parameter in the optimization of antibody therapeutics. Here, we describe the production of the anti-cancer monoclonal antibody rituximab in the unicellular ciliate, Tetrahymena thermophila. The resulting antibody demonstrated enhanced antibody-dependent cell-mediated cytotoxicity, which we attribute to unusual N-linked glycosylation. Detailed chromatographic and mass spectrometric analysis revealed afucosylated, oligomannose-type glycans, which, as a whole, displayed isomeric structures that deviate from the typical human counterparts, but whose branches were equivalent to fragments of metabolic intermediates observed in human glycoproteins. From the analysis of deposited crystal structures, we predict that the ciliate glycans adopt protein-carbohydrate interactions with the Fc domain that closely mimic those of native complex-type glycans. In addition, terminal glucose structures were identified that match biosynthetic precursors of human glycosylation. Our results suggest that ciliate-based expression systems offer a route to large-scale production of monoclonal antibodies exhibiting glycosylation that imparts enhanced cell killing activity.
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Affiliation(s)
| | - Anna-Janina Behrens
- b Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford , Oxford , UK
| | | | | | - Weston B Struwe
- b Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford , Oxford , UK
| | - David J Harvey
- b Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford , Oxford , UK
| | - Kai U Cormann
- c Plant Biochemistry, Ruhr University Bochum , Bochum , Germany
| | - Marc M Nowaczyk
- c Plant Biochemistry, Ruhr University Bochum , Bochum , Germany
| | - Karin Loser
- d Department of Dermatology , University of Münster , Münster , Germany
| | - Daniel Schinor
- e Wessling GmbH, Pharmaanalytik Münster , Münster , Germany
| | | | - Max Crispin
- b Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford , Oxford , UK
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14
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Le NPL, Bowden TA, Struwe WB, Crispin M. Immune recruitment or suppression by glycan engineering of endogenous and therapeutic antibodies. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1860:1655-68. [PMID: 27105835 PMCID: PMC4922387 DOI: 10.1016/j.bbagen.2016.04.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 04/15/2016] [Accepted: 04/16/2016] [Indexed: 12/20/2022]
Abstract
Human serum IgG contains multiple glycoforms which exhibit a range of binding properties to effector molecules such as cellular Fc receptors. Emerging knowledge of how the Fc glycans contribute to the antibody structure and effector functions has opened new avenues for the exploitation of defined antibody glycoforms in the treatment of diseases. Here, we review the structure and activity of antibody glycoforms and highlight developments in antibody glycoengineering by both the manipulation of the cellular glycosylation machinery and by chemoenzymatic synthesis. We discuss wide ranging applications of antibody glycoengineering in the treatment of cancer, autoimmunity and inflammation. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc.
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Affiliation(s)
- Ngoc Phuong Lan Le
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Thomas A Bowden
- Division of Structural Biology, University of Oxford, Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, United Kingdom
| | - Weston B Struwe
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Max Crispin
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom.
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15
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Agostino M, Mancera RL, Ramsland PA, Fernández-Recio J. Optimization of protein-protein docking for predicting Fc-protein interactions. J Mol Recognit 2016; 29:555-568. [PMID: 27445195 DOI: 10.1002/jmr.2555] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 06/12/2016] [Accepted: 06/14/2016] [Indexed: 01/08/2023]
Abstract
The antibody crystallizable fragment (Fc) is recognized by effector proteins as part of the immune system. Pathogens produce proteins that bind Fc in order to subvert or evade the immune response. The structural characterization of the determinants of Fc-protein association is essential to improve our understanding of the immune system at the molecular level and to develop new therapeutic agents. Furthermore, Fc-binding peptides and proteins are frequently used to purify therapeutic antibodies. Although several structures of Fc-protein complexes are available, numerous others have not yet been determined. Protein-protein docking could be used to investigate Fc-protein complexes; however, improved approaches are necessary to efficiently model such cases. In this study, a docking-based structural bioinformatics approach is developed for predicting the structures of Fc-protein complexes. Based on the available set of X-ray structures of Fc-protein complexes, three regions of the Fc, loosely corresponding to three turns within the structure, were defined as containing the essential features for protein recognition and used as restraints to filter the initial docking search. Rescoring the filtered poses with an optimal scoring strategy provided a success rate of approximately 80% of the test cases examined within the top ranked 20 poses, compared to approximately 20% by the initial unrestrained docking. The developed docking protocol provides a significant improvement over the initial unrestrained docking and will be valuable for predicting the structures of currently undetermined Fc-protein complexes, as well as in the design of peptides and proteins that target Fc.
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Affiliation(s)
- Mark Agostino
- School of Biomedical Sciences, Curtin Health Innovation Research Institute and Curtin Institute for Computation, Curtin University, Perth, Australia.,Joint BSC-CRG-IRB Research Program in Computational Biology, Life Sciences Department, Barcelona Supercomputing Center, Barcelona, Spain.,Centre for Biomedical Research, Burnet Institute, Melbourne, Australia
| | - Ricardo L Mancera
- School of Biomedical Sciences, Curtin Health Innovation Research Institute and Curtin Institute for Computation, Curtin University, Perth, Australia
| | - Paul A Ramsland
- Centre for Biomedical Research, Burnet Institute, Melbourne, Australia. .,School of Science, RMIT University, Bundoora, Australia. .,Department of Surgery Austin Health, University of Melbourne, Heidelberg, Australia. .,Department of Immunology, Monash University, Alfred Medical Research and Education Precinct, Melbourne, Australia.
| | - Juan Fernández-Recio
- Joint BSC-CRG-IRB Research Program in Computational Biology, Life Sciences Department, Barcelona Supercomputing Center, Barcelona, Spain.
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16
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Chen W, Kong L, Connelly S, Dendle JM, Liu Y, Wilson IA, Powers ET, Kelly JW. Stabilizing the CH2 Domain of an Antibody by Engineering in an Enhanced Aromatic Sequon. ACS Chem Biol 2016; 11:1852-61. [PMID: 27128252 DOI: 10.1021/acschembio.5b01035] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Monoclonal antibodies (mAbs) exhibiting highly selective binding to a protein target constitute a large and growing proportion of the therapeutics market. Aggregation of mAbs results in the loss of their therapeutic efficacy and can result in deleterious immune responses. The CH2 domain comprising part of the Fc portion of Immunoglobulin G (IgG) is typically the least stable domain in IgG-type antibodies and therefore influences their aggregation propensity. We stabilized the CH2 domain by engineering an enhanced aromatic sequon (EAS) into the N-glycosylated C'E loop and observed a 4.8 °C increase in the melting temperature of the purified IgG1 Fc fragment. This EAS-stabilized CH2 domain also conferred enhanced stability against thermal and low pH induced aggregation in the context of a full-length monoclonal IgG1 antibody. The crystal structure of the EAS-stabilized (Q295F/Y296A) IgG1 Fc fragment confirms the design principle, i.e., the importance of the GlcNAc1•F295 interaction, and surprisingly reveals that the core fucose attached to GlcNAc1 also engages in an interaction with F295. Inhibition of core fucosylation confirms the contribution of the fucose-Phe interaction to the stabilization. The Q295F/Y296A mutations also modulate the binding affinity of the full-length antibody to Fc receptors by decreasing the binding to low affinity Fc gamma receptors (FcγRIIa, FcγRIIIa, and FcγRIIIb), while maintaining wild-type binding affinity to FcRn and FcγRI. Our results demonstrate that engineering an EAS into the N-glycosylated reverse turn on the C'E loop leads to stabilizing N-glycan-protein interactions in antibodies and that this modification modulates antibody-Fc receptor binding.
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Affiliation(s)
- Wentao Chen
- Department
of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, United States
- Department
of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Leopold Kong
- Department
of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Stephen Connelly
- Department
of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Julia M. Dendle
- Department
of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, United States
- Department
of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Yu Liu
- Department
of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, United States
- Department
of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Ian A. Wilson
- Department
of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California 92037, United States
- The
Skaggs Institute for Chemical Biology, The Scripps Research Institute, La
Jolla, California 92037, United States
| | - Evan T. Powers
- Department
of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Jeffery W. Kelly
- Department
of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, United States
- Department
of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
- The
Skaggs Institute for Chemical Biology, The Scripps Research Institute, La
Jolla, California 92037, United States
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17
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Chang VT, Spooner RA, Crispin M, Davis SJ. Glycan Remodeling with Processing Inhibitors and Lectin-Resistant Eukaryotic Cells. Methods Mol Biol 2016; 1321:307-22. [PMID: 26082231 DOI: 10.1007/978-1-4939-2760-9_21] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Some of the most important and interesting molecules in metazoan biology are glycoproteins. The importance of the carbohydrate component of these structures is often revealed by the disease phenotypes that manifest when the biosynthesis of particular glycoforms is disrupted. On the other hand, the presence of large amounts of carbohydrate can often hinder the structural and functional analysis of glycoproteins. There are often good reasons, therefore, for wanting to engineer and predefine the N-glycans present on glycoproteins, e.g., in order to characterize the functions of the glycans or facilitate their subsequent removal. Here, we describe in detail two distinct ways in which to usefully interfere with oligosaccharide processing, one involving the use of specific processing inhibitors, and the other the selection of cell lines mutated at gene loci that control oligosaccharide processing, using cytotoxic lectins. Both approaches have the capacity for controlled, radical alteration of oligosaccharide processing in eukaryotic cells used for heterologous protein expression, and have great utility in the structural analysis of glycoproteins.
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Affiliation(s)
- Veronica T Chang
- Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK
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18
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Fang J, Richardson J, Du Z, Zhang Z. Effect of Fc-Glycan Structure on the Conformational Stability of IgG Revealed by Hydrogen/Deuterium Exchange and Limited Proteolysis. Biochemistry 2016; 55:860-8. [PMID: 26812426 DOI: 10.1021/acs.biochem.5b01323] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Human therapeutic immunoglobulin gamma (IgG) molecules contain an N-glycan on each of their Fc CH2 domains. These glycans include high-mannose, hybrid, and complex types. Recombinant IgG molecules containing high-mannose glycans have been shown to clear faster in human blood, and exhibit decreased thermal stability. The molecular mechanism behind these observations, however, is not well understood. In this work, we used hydrogen/deuterium exchange combined with mass spectrometry (HDX MS), as well as proteolytic degradation under a native-like condition, to assess the impact of different glycoforms on the molecular structure and stability of recombinant IgG1 and IgG2 molecules expressed from Chinese hamster ovary cells. Our HDX MS data indicate that the conformation of these IgG molecules was indeed influenced by the glycan structure. IgG molecules containing high-mannose and hybrid glycans showed more conformational flexibility in the CH2 domain. This conclusion was further supported by the analysis of glycopeptides released from these molecules by trypsin digestion under a native-like condition. The higher CH2 conformational flexibility of IgG molecules with high-mannose and hybrid glycans contributes to their decreased thermal stability. IgG molecules containing sialylated glycans in the CH2 domain exhibited similar enzymatic degradation behavior as high-mannose glycans, suggesting decreased CH2-domain stability compared to shorter complex glycans, likely resulting from steric effect that decreased the glycan-CH2 domain interaction.
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Affiliation(s)
- Jing Fang
- Process Development, Amgen, Inc. , Thousand Oaks, California 91320, United States
| | - Jason Richardson
- Process Development, Amgen, Inc. , Thousand Oaks, California 91320, United States
| | - Zhimei Du
- Process Development, Amgen, Inc. , Seattle, Washington 98119, United States
| | - Zhongqi Zhang
- Process Development, Amgen, Inc. , Thousand Oaks, California 91320, United States
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19
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Subedi GP, Barb AW. The Structural Role of Antibody N-Glycosylation in Receptor Interactions. Structure 2015; 23:1573-1583. [PMID: 26211613 PMCID: PMC4558368 DOI: 10.1016/j.str.2015.06.015] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 06/08/2015] [Accepted: 06/10/2015] [Indexed: 01/06/2023]
Abstract
Asparagine(N)297-linked glycosylation of immunoglobulin G (IgG) Fc is required for binding to FcγRIIa, IIb, and IIIa, although it is unclear how it contributes. We found the quaternary structure of glycosylated Fc was indistinguishable from aglycosylated Fc, indicating that N-glycosylation does not maintain relative Fc Cγ2/Cγ3 domain orientation. However, the conformation of the C'E loop, which contains N297, was significantly perturbed in the aglycosylated Fc variant. The conformation of the C'E loop as measured with a range of Fc variants shows a strong correlation with FcγRIIIa affinity. These results indicate that the primary role of the IgG1 Fc N-glycan is to stabilize the C'E loop through intramolecular interactions between carbohydrate and amino acid residues, and preorganize the FcγRIIIa interface for optimal binding affinity. The features that contribute to the capacity of the IgG1 Fc N-glycan to restrict protein conformation and tune binding affinity are conserved in other antibodies including IgG2-IgG4, IgD, IgE, and IgM.
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Affiliation(s)
- Ganesh P Subedi
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, 2214 Molecular Biology Building, Ames, IA 50011, USA
| | - Adam W Barb
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, 2214 Molecular Biology Building, Ames, IA 50011, USA.
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20
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Kurogochi M, Mori M, Osumi K, Tojino M, Sugawara SI, Takashima S, Hirose Y, Tsukimura W, Mizuno M, Amano J, Matsuda A, Tomita M, Takayanagi A, Shoda SI, Shirai T. Glycoengineered Monoclonal Antibodies with Homogeneous Glycan (M3, G0, G2, and A2) Using a Chemoenzymatic Approach Have Different Affinities for FcγRIIIa and Variable Antibody-Dependent Cellular Cytotoxicity Activities. PLoS One 2015. [PMID: 26200113 PMCID: PMC4511734 DOI: 10.1371/journal.pone.0132848] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Many therapeutic antibodies have been developed, and IgG antibodies have been extensively generated in various cell expression systems. IgG antibodies contain N-glycans at the constant region of the heavy chain (Fc domain), and their N-glycosylation patterns differ during various processes or among cell expression systems. The Fc N-glycan can modulate the effector functions of IgG antibodies, such as antibody-dependent cellular cytotoxicity (ADCC) and complement dependent cytotoxicity (CDC). To control Fc N-glycans, we performed a rearrangement of Fc N-glycans from a heterogeneous N-glycosylation pattern to homogeneous N-glycans using chemoenzymatic approaches with two types of endo-β-N-acetyl glucosaminidases (ENG'ases), one that works as a hydrolase to cleave all heterogeneous N-glycans, another that is used as a glycosynthase to generate homogeneous N-glycans. As starting materials, we used an anti-Her2 antibody produced in transgenic silkworm cocoon, which consists of non-fucosylated pauci-mannose type (Man2-3GlcNAc2), high-mannose type (Man4-9GlcNAc2), and complex type (Man3GlcNAc3-4) N-glycans. As a result of the cleavage of several ENG'ases (endoS, endoM, endoD, endoH, and endoLL), the heterogeneous glycans on antibodies were fully transformed into homogeneous-GlcNAc by a combination of endoS, endoD, and endoLL. Next, the desired N-glycans (M3; Man3GlcNAc1, G0; GlcNAc2Man3GlcNAc1, G2; Gal2GlcNAc2Man3GlcNAc1, A2; NeuAc2Gal2GlcNAc2Man3GlcNAc1) were transferred from the corresponding oxazolines to the GlcNAc residue on the intact anti-Her2 antibody with an ENG'ase mutant (endoS-D233Q), and the glycoengineered anti-Her2 antibody was obtained. The binding assay of anti-Her2 antibody with homogenous N-glycans with FcγRIIIa-V158 showed that the glycoform influenced the affinity for FcγRIIIa-V158. In addition, the ADCC assay for the glycoengineered anti-Her2 antibody (mAb-M3, mAb-G0, mAb-G2, and mAb-A2) was performed using SKBR-3 and BT-474 as target cells, and revealed that the glycoform influenced ADCC activity.
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Affiliation(s)
- Masaki Kurogochi
- Laboratory of Glycobiology, The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo, Japan
| | - Masako Mori
- Laboratory of Glyco-Bioengineering, The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo, Japan
| | - Kenji Osumi
- Laboratory of Glyco-organic Chemistry, The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo, Japan
| | - Mami Tojino
- Laboratory of Glyco-organic Chemistry, The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo, Japan
| | - Shu-ichi Sugawara
- Laboratory of Glyco-organic Chemistry, The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo, Japan
| | - Shou Takashima
- Laboratory of Glycobiology, The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo, Japan
| | - Yuriko Hirose
- Laboratory of Glyco-organic Chemistry, The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo, Japan
| | - Wataru Tsukimura
- Laboratory of Glyco-Bioengineering, The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo, Japan
| | - Mamoru Mizuno
- Laboratory of Glyco-organic Chemistry, The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo, Japan
| | - Junko Amano
- Laboratory of Glycobiology, The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo, Japan
| | - Akio Matsuda
- Laboratory of Glyco-Bioengineering, The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo, Japan
| | - Masahiro Tomita
- Immuno-Biological Laboratories Co., Ltd., 1091-1 Naka, Fujioka-shi, Gunma, Japan
| | - Atsushi Takayanagi
- Department of Molecular Biology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, Japan
| | - Shin-Ichiro Shoda
- Graduate School of Engineering, Tohoku University, Aoba-ku, Sendai, Japan
| | - Takashi Shirai
- Laboratory of Glycobiology, The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo, Japan
- Laboratory of Glyco-Bioengineering, The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo, Japan
- Laboratory of Glyco-organic Chemistry, The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo, Japan
- * E-mail:
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21
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Piscitelli CL, Kean J, de Graaf C, Deupi X. A Molecular Pharmacologist's Guide to G Protein-Coupled Receptor Crystallography. Mol Pharmacol 2015; 88:536-51. [PMID: 26152196 DOI: 10.1124/mol.115.099663] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 07/07/2015] [Indexed: 12/14/2022] Open
Abstract
G protein-coupled receptor (GPCR) structural biology has progressed dramatically in the last decade. There are now over 120 GPCR crystal structures deposited in the Protein Data Bank of 32 different receptors from families scattered across the phylogenetic tree, including class B, C, and Frizzled GPCRs. These structures have been obtained in combination with a wide variety of ligands and captured in a range of conformational states. This surge in structural knowledge has enlightened research into the molecular recognition of biologically active molecules, the mechanisms of receptor activation, the dynamics of functional selectivity, and fueled structure-based drug design efforts for GPCRs. Here we summarize the innovations in both protein engineering/molecular biology and crystallography techniques that have led to these advances in GPCR structural biology and discuss how they may influence the resulting structural models. We also provide a brief molecular pharmacologist's guide to GPCR X-ray crystallography, outlining some key aspects in the process of structure determination, with the goal to encourage noncrystallographers to interrogate structures at the molecular level. Finally, we show how chemogenomics approaches can be used to marry the wealth of existing receptor pharmacology data with the expanding repertoire of structures, providing a deeper understanding of the mechanistic details of GPCR function.
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Affiliation(s)
- Chayne L Piscitelli
- Laboratory of Biomolecular Research, Department of Biology and Chemistry (C.L.P., X.D.), and Condensed Matter Theory Group, Department of Research with Neutrons and Muons (X.D.), Paul Scherrer Institute, Villigen, Switzerland; Heptares Therapeutics Ltd., Welwyn Garden City, United Kingdom (J.K.); and Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems, VU University of Amsterdam, Amsterdam, The Netherlands (C.G.)
| | - James Kean
- Laboratory of Biomolecular Research, Department of Biology and Chemistry (C.L.P., X.D.), and Condensed Matter Theory Group, Department of Research with Neutrons and Muons (X.D.), Paul Scherrer Institute, Villigen, Switzerland; Heptares Therapeutics Ltd., Welwyn Garden City, United Kingdom (J.K.); and Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems, VU University of Amsterdam, Amsterdam, The Netherlands (C.G.)
| | - Chris de Graaf
- Laboratory of Biomolecular Research, Department of Biology and Chemistry (C.L.P., X.D.), and Condensed Matter Theory Group, Department of Research with Neutrons and Muons (X.D.), Paul Scherrer Institute, Villigen, Switzerland; Heptares Therapeutics Ltd., Welwyn Garden City, United Kingdom (J.K.); and Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems, VU University of Amsterdam, Amsterdam, The Netherlands (C.G.)
| | - Xavier Deupi
- Laboratory of Biomolecular Research, Department of Biology and Chemistry (C.L.P., X.D.), and Condensed Matter Theory Group, Department of Research with Neutrons and Muons (X.D.), Paul Scherrer Institute, Villigen, Switzerland; Heptares Therapeutics Ltd., Welwyn Garden City, United Kingdom (J.K.); and Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems, VU University of Amsterdam, Amsterdam, The Netherlands (C.G.)
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22
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Hanson QM, Barb AW. A perspective on the structure and receptor binding properties of immunoglobulin G Fc. Biochemistry 2015; 54:2931-42. [PMID: 25926001 DOI: 10.1021/acs.biochem.5b00299] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Recombinant antibodies spurred a revolution in medicine that saw the introduction of powerful therapeutics for treating a wide range of diseases, from cancers to autoimmune disorders and transplant rejection, with more applications looming on the horizon. Many of these therapeutic monoclonal antibodies (mAbs) are based on human immunoglobulin G1 (IgG1) or contain at least a portion of the molecule. Most mAbs require interactions with cell surface receptors for efficacy, including the Fc γ receptors. High-resolution structural models of antibodies and antibody fragments have been available for nearly 40 years; however, a thorough description of the structural features that determine the affinity with which antibodies interact with human receptors has not been published. In this review, we will cover the relevant history of IgG-related literature and how recent developments have changed our view of critical antibody-cell interactions at the atomic level with a nod to outstanding questions in the field and future prospects.
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Affiliation(s)
- Quinlin M Hanson
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, 2214 Molecular Biology Building, Ames, Iowa 50011, United States
| | - Adam W Barb
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, 2214 Molecular Biology Building, Ames, Iowa 50011, United States
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23
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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.
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Affiliation(s)
- David J. Harvey
- Department of BiochemistryOxford Glycobiology InstituteUniversity of OxfordOxfordOX1 3QUUK
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24
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Czajkowsky DM, Andersen JT, Fuchs A, Wilson TJ, Mekhaiel D, Colonna M, He J, Shao Z, Mitchell DA, Wu G, Dell A, Haslam S, Lloyd KA, Moore SC, Sandlie I, Blundell PA, Pleass RJ. Developing the IVIG biomimetic, hexa-Fc, for drug and vaccine applications. Sci Rep 2015; 5:9526. [PMID: 25912958 PMCID: PMC5224519 DOI: 10.1038/srep09526] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 02/26/2015] [Indexed: 12/20/2022] Open
Abstract
The remarkable clinical success of Fc-fusion proteins has driven intense investigation for even more potent replacements. Using quality-by-design (QbD) approaches, we generated hexameric-Fc (hexa-Fc), a ~20 nm oligomeric Fc-based scaffold that we here show binds low-affinity inhibitory receptors (FcRL5, FcγRIIb, and DC-SIGN) with high avidity and specificity, whilst eliminating significant clinical limitations of monomeric Fc-fusions for vaccine and/or cancer therapies, in particular their poor ability to activate complement. Mass spectroscopy of hexa-Fc reveals high-mannose, low-sialic acid content, suggesting that interactions with these receptors are influenced by the mannose-containing Fc. Molecular dynamics (MD) simulations provides insight into the mechanisms of hexa-Fc interaction with these receptors and reveals an unexpected orientation of high-mannose glycans on the human Fc that provides greater accessibility to potential binding partners. Finally, we show that this biosynthetic nanoparticle can be engineered to enhance interactions with the human neonatal Fc receptor (FcRn) without loss of the oligomeric structure, a crucial modification for these molecules in therapy and/or vaccine strategies where a long plasma half-life is critical.
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Affiliation(s)
- Daniel M Czajkowsky
- Bio-ID Center, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240 P. R. China
| | - Jan Terje Andersen
- Centre for Immune Regulation (CIR) and Department of Immunology, Oslo University Hospital Rikshospitalet, P.O. Box 4956, Oslo N-0424, Norway
| | - Anja Fuchs
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Timothy J Wilson
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - David Mekhaiel
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Marco Colonna
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jianfeng He
- Bio-ID Center, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240 P. R. China
| | - Zhifeng Shao
- Bio-ID Center, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240 P. R. China
| | - Daniel A Mitchell
- Clinical Sciences Research Laboratories, Warwick Medical School, University of Warwick, Coventry CV2 2DX, UK
| | - Gang Wu
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7
| | - Anne Dell
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7
| | - Stuart Haslam
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7
| | - Katy A Lloyd
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Shona C Moore
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Inger Sandlie
- 1] Centre for Immune Regulation (CIR) and Department of Immunology, Oslo University Hospital Rikshospitalet, P.O. Box 4956, Oslo N-0424, Norway [2] CIR and Department of Biosciences, University of Oslo, N-0316 Oslo, Norway
| | - Patricia A Blundell
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Richard J Pleass
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
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25
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Garner OB, Yun T, Pernet O, Aguilar HC, Park A, Bowden TA, Freiberg AN, Lee B, Baum LG. Timing of galectin-1 exposure differentially modulates Nipah virus entry and syncytium formation in endothelial cells. J Virol 2015; 89:2520-9. [PMID: 25505064 PMCID: PMC4325760 DOI: 10.1128/jvi.02435-14] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 10/03/2014] [Indexed: 12/16/2022] Open
Abstract
UNLABELLED Nipah virus (NiV) is a deadly emerging enveloped paramyxovirus that primarily targets human endothelial cells. Endothelial cells express the innate immune effector galectin-1 that we have previously shown can bind to specific N-glycans on the NiV envelope fusion glycoprotein (F). NiV-F mediates fusion of infected endothelial cells into syncytia, resulting in endothelial disruption and hemorrhage. Galectin-1 is an endogenous carbohydrate-binding protein that binds to specific glycans on NiV-F to reduce endothelial cell fusion, an effect that may reduce pathophysiologic sequelae of NiV infection. However, galectins play multiple roles in regulating host-pathogen interactions; for example, galectins can promote attachment of HIV to T cells and macrophages and attachment of HSV-1 to keratinocytes but can also inhibit influenza entry into airway epithelial cells. Using live Nipah virus, in the present study, we demonstrate that galectin-1 can enhance NiV attachment to and infection of primary human endothelial cells by bridging glycans on the viral envelope to host cell glycoproteins. In order to exhibit an enhancing effect, galectin-1 must be present during the initial phase of virus attachment; in contrast, addition of galectin-1 postinfection results in reduced production of progeny virus and syncytium formation. Thus, galectin-1 can have dual and opposing effects on NiV infection of human endothelial cells. While various roles for galectin family members in microbial-host interactions have been described, we report opposing effects of the same galectin family member on a specific virus, with the timing of exposure during the viral life cycle determining the outcome. IMPORTANCE Nipah virus is an emerging pathogen that targets endothelial cells lining blood vessels; the high mortality rate (up to 70%) in Nipah virus infections results from destruction of these cells and resulting catastrophic hemorrhage. Host factors that promote or prevent Nipah virus infection are not well understood. Endogenous human lectins, such as galectin-1, can function as pattern recognition receptors to reduce infection and initiate immune responses; however, lectins can also be exploited by microbes to enhance infection of host cells. We found that galectin-1, which is made by inflamed endothelial cells, can both promote Nipah virus infection of endothelial cells by "bridging" the virus to the cell, as well as reduce production of progeny virus and reduce endothelial cell fusion and damage, depending on timing of galectin-1 exposure. This is the first report of spatiotemporal opposing effects of a host lectin for a virus in one type of host cell.
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Affiliation(s)
- Omai B Garner
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Tatyana Yun
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Olivier Pernet
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Hector C Aguilar
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - Arnold Park
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Thomas A Bowden
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Alexander N Freiberg
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Benhur Lee
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Linda G Baum
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
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26
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27
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Ahmed AA, Giddens J, Pincetic A, Lomino JV, Ravetch JV, Wang LX, Bjorkman PJ. Structural characterization of anti-inflammatory immunoglobulin G Fc proteins. J Mol Biol 2014; 426:3166-3179. [PMID: 25036289 DOI: 10.1016/j.jmb.2014.07.006] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 06/13/2014] [Accepted: 07/07/2014] [Indexed: 12/13/2022]
Abstract
Immunoglobulin G (IgG) is a central mediator of host defense due to its ability to recognize and eliminate pathogens. The recognition and effector responses are encoded on distinct regions of IgGs. The diversity of the antigen recognition Fab domains accounts for IgG's ability to bind with high specificity to essentially any antigen. Recent studies have indicated that the Fc effector domain also displays considerable heterogeneity, accounting for its complex effector functions of inflammation, modulation, and immune suppression. Therapeutic anti-tumor antibodies, for example, require the pro-inflammatory properties of the IgG Fc to eliminate tumor cells, while the anti-inflammatory activity of intravenous IgG requires specific Fc glycans for activity. In particular, the anti-inflammatory activity of intravenous IgG is ascribed to a small population of IgGs in which the Asn297-linked complex N-glycans attached to each Fc CH2 domain include terminal α2,6-linked sialic acids. We used chemoenzymatic glycoengineering to prepare fully disialylated IgG Fc and solved its crystal structure. Comparison of the structures of asialylated Fc, sialylated Fc, and F241A Fc, a mutant that displays increased glycan sialylation, suggests that increased conformational flexibility of the CH2 domain is associated with the switch from pro-inflammatory to anti-inflammatory activity of the Fc.
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Affiliation(s)
- Alysia A Ahmed
- Division of Biology and Biological Engineering 114-96, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - John Giddens
- Institute of Human Virology and Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Andrew Pincetic
- Laboratory of Molecular Genetics and Immunology, The Rockefeller University, 1230 York Avenue, New York, NY 10065. USA
| | - Joseph V Lomino
- Institute of Human Virology and Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jeffrey V Ravetch
- Laboratory of Molecular Genetics and Immunology, The Rockefeller University, 1230 York Avenue, New York, NY 10065. USA
| | - Lai-Xi Wang
- Institute of Human Virology and Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Pamela J Bjorkman
- Division of Biology and Biological Engineering 114-96, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA; Howard Hughes Medical Institute, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA.
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28
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The choice of mammalian cell host and possibilities for glycosylation engineering. Curr Opin Biotechnol 2014; 30:107-12. [PMID: 25005678 DOI: 10.1016/j.copbio.2014.06.010] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 06/12/2014] [Accepted: 06/12/2014] [Indexed: 11/20/2022]
Abstract
Non-human mammalian cells such as CHO have been used predominantly for the production of biopharmaceuticals including monoclonal antibodies (Mabs). Although the glycosylation profile of these products is 'human-like' there is still the possibility of immunogenic epitopes such as α-Gal and Neu5Gc. Human cell lines have now been designed for high productivity of recombinant proteins and ensuring authentic glycosylation patterns. The control of glycosylation on such proteins is important for the efficacy of recombinant biopharmaceuticals as well as the immunogenic properties of viral vaccines such as influenza. We are now starting to understand some of the relationships between the structure of glycans and the function bestowed on the associated protein. This has promoted cell culture technologies for the targeted control of glycosylation to produce pre-determined glycan profiles of secreted products.
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29
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Davies AM, Jefferis R, Sutton BJ. Crystal structure of deglycosylated human IgG4-Fc. Mol Immunol 2014; 62:46-53. [PMID: 24956411 PMCID: PMC4166458 DOI: 10.1016/j.molimm.2014.05.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 05/29/2014] [Indexed: 12/24/2022]
Abstract
The first crystal structure of deglycosylated human IgG4-Fc is reported at 2.7 Å resolution. The asymmetric unit comprises a novel interlocked arrangement of two IgG4-Fc molecules. The CH2 domains are oriented in an “open” arrangement. The structure of the CH2 domain DE loop is altered in the absence of carbohydrate. Crystal packing reveals a hexameric Fc arrangement.
The Fc region of IgG antibodies, important for effector functions such as antibody-dependent cell-mediated cytotoxicity, antibody-dependent cellular phagocytosis and complement activation, contains an oligosaccharide moiety covalently attached to each CH2 domain. The oligosaccharide not only orients the CH2 domains but plays an important role in influencing IgG effector function, and engineering the IgG-Fc oligosaccharide moiety is an important aspect in the design of therapeutic monoclonal IgG antibodies. Recently we reported the crystal structure of glycosylated IgG4-Fc, revealing structural features that could explain the anti-inflammatory biological properties of IgG4 compared with IgG1. We now report the crystal structure of enzymatically deglycosylated IgG4-Fc, derived from human serum, at 2.7 Å resolution. Intermolecular CH2-CH2 domain interactions partially bury the CH2 domain surface that would otherwise be exposed by the absence of oligosaccharide, and two Fc molecules are interlocked in a symmetric, open conformation. The conformation of the CH2 domain DE loop, to which oligosaccharide is attached, is altered in the absence of carbohydrate. Furthermore, the CH2 domain FG loop, important for Fcγ receptor and C1q binding, adopts two different conformations. One loop conformation is unique to IgG4 and would disrupt binding, consistent with IgG4's anti-inflammatory properties. The second is similar to the conserved conformation found in IgG1, suggesting that in contrast to IgG1, the IgG4 CH2 FG loop is dynamic. Finally, crystal packing reveals a hexameric arrangement of IgG4-Fc molecules, providing further clues about the interaction between C1q and IgG.
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Affiliation(s)
- Anna M Davies
- King's College London, Randall Division of Cell and Molecular Biophysics, New Hunt's House, London SE1 1UL, United Kingdom; Medical Research Council & Asthma UK Centre in Allergic Mechanisms of Asthma, London, United Kingdom.
| | - Roy Jefferis
- University of Birmingham, College of Medical & Dental Sciences, School of Immunity & Infection, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Brian J Sutton
- King's College London, Randall Division of Cell and Molecular Biophysics, New Hunt's House, London SE1 1UL, United Kingdom; Medical Research Council & Asthma UK Centre in Allergic Mechanisms of Asthma, London, United Kingdom.
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30
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Zheng K, Yarmarkovich M, Bantog C, Bayer R, Patapoff TW. Influence of glycosylation pattern on the molecular properties of monoclonal antibodies. MAbs 2014; 6:649-58. [PMID: 24662970 DOI: 10.4161/mabs.28588] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Glycosylation is an important post-translational modification during protein production in eukaryotic cells, and it is essential for protein structure, stability, half-life, and biological functions. In this study, we produced various monoclonal antibody (mAb) glycoforms from Chinese hamster ovary (CHO) cells, including the natively glycosylated antibody, the enriched G0 form, the deglycosylated form, the afucosylated form, and the high mannose form, and we compared their intrinsic properties, side-by-side, through biophysical and biochemical approaches. Spectroscopic analysis indicates no measureable secondary or tertiary structural changes after in vitro or in vivo modification of the glycosylation pattern. Thermal unfolding experiments show that the high mannose and deglycosylated forms have reduced thermal stability of the CH2 domain compared with the other tested glycoforms. We also observed that the individual domain's thermal stability could be pH dependent. Proteolysis analysis indicates that glycosylation plays an important role in stabilizing mAbs against proteases. The stability of antibody glycoforms at the storage condition (2-8 °C) and at accelerated conditions (30 and 40 °C) was evaluated, and the results indicate that glycosylation patterns do not substantially affect the storage stability of the antibody we studied.
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Affiliation(s)
- Kai Zheng
- Late Stage Pharmaceutical Development; Genentech Inc.; South San Francisco, CA USA; Formerly at Oceanside Pharma Technical Development; Genentech Inc.; Oceanside, CA USA
| | - Mark Yarmarkovich
- Formerly at Oceanside Pharma Technical Development; Genentech Inc.; Oceanside, CA USA; Department of Cancer Biology; Perelman School of Medicine; University of Pennsylvania; Philadelphia, PA USA
| | - Christopher Bantog
- Formerly at Oceanside Pharma Technical Development; Genentech Inc.; Oceanside, CA USA; Department of Chemistry Development; Illumina Inc.; San Diego, CA USA
| | - Robert Bayer
- Formerly at Oceanside Pharma Technical Development; Genentech Inc.; Oceanside, CA USA; Biotherapeutics Development Unit; Novartis Inc.; San Diego, CA USA
| | - Thomas W Patapoff
- Early Stage Pharmaceutical Development; Genentech Inc.; South San Francisco, CA USA
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31
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Immunoglobulin G1 Fc domain motions: implications for Fc engineering. J Mol Biol 2014; 426:1799-811. [PMID: 24522230 DOI: 10.1016/j.jmb.2014.01.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 01/05/2014] [Accepted: 01/29/2014] [Indexed: 12/22/2022]
Abstract
The fragment crystallizable (Fc) region links the key pathogen identification and destruction properties of immunoglobulin G (IgG). Pathogen opsonization positions Fcs to activate pro-inflammatory Fcγ receptors (FcγRs) on immune cells. The cellular response and committal to a damaging, though protective, immune response are tightly controlled at multiple levels. Control mechanisms are diverse and in many cases unclear, but one frequently suggested contribution originates in FcγR affinity being modulated through shifts in Fc conformational sampling. Here, we report a previously unseen IgG1 Fc conformation. This observation motivated an extensive molecular dynamics investigation of polypeptide and glycan motions that revealed greater amplitude of motion for the N-terminal Cγ2 domains and N-glycan than previously observed. Residues in the Cγ2/Cγ3 interface and disulfide-bonded hinge were identified as influencing the Cγ2 motion. Our results are consistent with a model of Fc that is structurally dynamic. Conformational states that are competent to bind immune-stimulating FcγRs interconverted with Fc conformations distinct from those observed in FcγR complexes, which may represent a transient, nonbinding population.
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32
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Dalziel M, Crispin M, Scanlan CN, Zitzmann N, Dwek RA. Emerging principles for the therapeutic exploitation of glycosylation. Science 2014; 343:1235681. [PMID: 24385630 DOI: 10.1126/science.1235681] [Citation(s) in RCA: 342] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Glycosylation plays a key role in a wide range of biological processes. Specific modification to a glycan's structure can directly modulate its biological function. Glycans are not only essential to glycoprotein folding, cellular homeostasis, and immune regulation but are involved in multiple disease conditions. An increased molecular and structural understanding of the mechanistic role that glycans play in these pathological processes has driven the development of therapeutics and illuminated novel targets for drug design. This knowledge has enabled the treatment of metabolic disorders and the development of antivirals and shaped cancer and viral vaccine strategies. Furthermore, an understanding of glycosylation has led to the development of specific drug glycoforms, for example, monoclonal antibodies, with enhanced potency.
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Affiliation(s)
- Martin Dalziel
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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33
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Rispens T, Davies AM, Ooijevaar-de Heer P, Absalah S, Bende O, Sutton BJ, Vidarsson G, Aalberse RC. Dynamics of inter-heavy chain interactions in human immunoglobulin G (IgG) subclasses studied by kinetic Fab arm exchange. J Biol Chem 2014; 289:6098-109. [PMID: 24425871 PMCID: PMC3937676 DOI: 10.1074/jbc.m113.541813] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Interdomain interactions between the CH3 domains of antibody heavy chains are the first step in antibody assembly and are of prime importance for maintaining the native structure of IgG. For human IgG4 it was shown that CH3-CH3 interactions are weak, resulting in the potential for half-molecule exchange (“Fab arm exchange”). Here we systematically investigated non-covalent interchain interactions for CH3 domains in the other human subclasses, including polymorphisms (allotypes), using real-time monitoring of Fab arm exchange with a FRET-based kinetic assay. We identified structural variation between human IgG subclasses and allotypes at three amino acid positions (Lys/Asn-392, Val/Met-397, Lys/Arg-409) to alter the strength of inter-domain interactions by >6 orders of magnitude. Each substitution affected the interactions independent from the other substitutions in terms of affinity, but the enthalpic and entropic contributions were non-additive, suggesting a complex interplay. Allotypic variation in IgG3 resulted in widely different CH3 interaction strengths that were even weaker for IgG3 than for IgG4 in the case of allotype G3m(c3c5*/6,24*), whereas G3m(s*/15*) was equally stable to IgG1. These interactions are sufficiently strong to maintain the structural integrity of IgG1 during its normal life span; for IgG2 and IgG3 the inter-heavy chain disulfide bonds are essential to prevent half-molecule dissociation, whereas the labile hinge disulfide bonds favor half-molecule exchange in vivo for IgG4.
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Affiliation(s)
- Theo Rispens
- From Sanquin Research, 1066 CX Amsterdam, The Netherlands, and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, 1105 AZ, The Netherlands
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34
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Huang X, Zheng F, Zhan CG. Binding structures and energies of the human neonatal Fc receptor with human Fc and its mutants by molecular modeling and dynamics simulations. MOLECULAR BIOSYSTEMS 2013; 9:3047-58. [PMID: 24057047 DOI: 10.1039/c3mb70231f] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Homology modeling and molecular dynamics simulations have been carried out to model the detailed structures of the human neonatal Fc receptor (FcRn) binding with the wild-type Fc of human immunoglobulin G1 (IgG1) and its various mutants. Based on the modeled human FcRn-Fc binding structures, it has been proposed that the protein-protein binding interface is composed of three subsites. The first subsite is a hydrophobic core where residue I39 of human Fc can be accommodated very well, and the other two subsites are all composed of critical salt bridges between human FcRn and human Fc. All of the modeled structures and the calculated binding energies are qualitatively consistent with the available experimental data, suggesting that the modeled human FcRn-Fc binding structures are reasonable. The modeled human FcRn-Fc binding structure may be valuable for future rational design of novel mutants of human Fc and Fc-fused therapeutic proteins with a potentially higher binding affinity for human FcRn and, thus, a longer in vivo half-life in humans.
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Affiliation(s)
- Xiaoqin Huang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536, USA.
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35
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Crystal structure of Venezuelan hemorrhagic fever virus fusion glycoprotein reveals a class 1 postfusion architecture with extensive glycosylation. J Virol 2013; 87:13070-5. [PMID: 24049182 PMCID: PMC3838125 DOI: 10.1128/jvi.02298-13] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Guanarito virus (GTOV) is an emergent and deadly pathogen. We present the crystal structure of the glycosylated GTOV fusion glycoprotein to 4.1-Å resolution in the postfusion conformation. Our structure reveals a classical six-helix bundle and presents direct verification that New World arenaviruses exhibit class I viral membrane fusion machinery. The structure provides visualization of an N-linked glycocalyx coat, and consideration of glycan dynamics reveals extensive coverage of the underlying protein surface, following virus-host membrane fusion.
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36
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Hacker DL, Kiseljak D, Rajendra Y, Thurnheer S, Baldi L, Wurm FM. Polyethyleneimine-based transient gene expression processes for suspension-adapted HEK-293E and CHO-DG44 cells. Protein Expr Purif 2013; 92:67-76. [PMID: 24021764 PMCID: PMC7129890 DOI: 10.1016/j.pep.2013.09.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 08/30/2013] [Accepted: 09/02/2013] [Indexed: 12/30/2022]
Abstract
A brief overview of principles of TGE using mammalian cells. Description of TGE processes for HEK293 and CHO cells. Description of orbitally shaken bioreactors for suspension cell cultivation. Description of polyethylenime-based transfection processes.
Transient gene expression (TGE) from mammalian cells is an increasingly important tool for the rapid production of recombinant proteins for research applications in biochemistry, structural biology, and biomedicine. Here we review methods for the transfection of human embryo kidney (HEK-293) and Chinese hamster ovary (CHO) cells in suspension culture using the cationic polymer polyethylenimine (PEI) for gene delivery.
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Affiliation(s)
- David L Hacker
- Protein Expression Core Facility, EPFL, CH-1015 Lausanne, Switzerland; Laboratory of Cellular Biotechnology, EPFL, CH-1015 Lausanne, Switzerland.
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37
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Costa AR, Rodrigues ME, Henriques M, Oliveira R, Azeredo J. Glycosylation: impact, control and improvement during therapeutic protein production. Crit Rev Biotechnol 2013; 34:281-99. [PMID: 23919242 DOI: 10.3109/07388551.2013.793649] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The emergence of the biopharmaceutical industry represented a major revolution for modern medicine, through the development of recombinant therapeutic proteins that brought new hope for many patients with previously untreatable diseases. There is a ever-growing demand for these therapeutics that forces a constant technological evolution to increase product yields while simultaneously reducing costs. However, the process changes made for this purpose may also affect the quality of the product, a factor that was initially overlooked but which is now a major focus of concern. Of the many properties determining product quality, glycosylation is regarded as one of the most important, influencing, for example, the biological activity, serum half-life and immunogenicity of the protein. Consequently, monitoring and control of glycosylation is now critical in biopharmaceutical manufacturing and a requirement of regulatory agencies. A rapid evolution is being observed in this context, concerning the influence of glycosylation in the efficacy of different therapeutic proteins, the impact on glycosylation of a diversity of parameters/processes involved in therapeutic protein production, the analytical methodologies employed for glycosylation monitoring and control, as well as strategies that are being explored to use this property to improve therapeutic protein efficacy (glycoengineering). This work reviews the main findings on these subjects, providing an up-to-date source of information to support further studies.
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Affiliation(s)
- Ana Rita Costa
- IBB - Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Campus de Gualtar , Braga , Portugal
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38
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Yu X, Baruah K, Harvey D, Vasiljevic S, Alonzi DS, Song BD, Higgins M, Bowden TA, Scanlan CN, Crispin M. Engineering hydrophobic protein-carbohydrate interactions to fine-tune monoclonal antibodies. J Am Chem Soc 2013; 135:9723-32. [PMID: 23745692 PMCID: PMC3788586 DOI: 10.1021/ja4014375] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Indexed: 12/20/2022]
Abstract
Biologically active conformations of the IgG1 Fc homodimer are maintained by multiple hydrophobic interactions between the protein surface and the N-glycan. The Fc glycan modulates biological effector functions, including antibody-dependent cellular cytotoxicity (ADCC) which is mediated in part through the activatory Fc receptor, FcγRIIIA. Consistent with previous reports, we found that site-directed mutations disrupting the protein-carbohydrate interface (F241A, F243A, V262E, and V264E) increased galactosylation and sialylation of the Fc and, concomitantly, reduced the affinity for FcγRIIIA. We rationalized this effect by crystallographic analysis of the IgG1 Fc F241A mutant, determined here to a resolution of 1.9 Å, which revealed localized destabilization of this glycan-protein interface. Given that sialylation of Fc glycans decreases ADCC, one explanation for the effect of these mutants on FcγRIIIA binding is their increased sialylation. However, a glycan-engineered IgG1 with hypergalactosylated and hypersialylated glycans exhibited unchanged binding affinity to FcγRIIIA. Moreover, when we expressed these mutants as a chemically uniform (Man5GlcNAc2) glycoform, the individual effect of each mutation on FcγRIIIA affinity was preserved. This effect was broadly recapitulated for other Fc receptors (FcγRI, FcγRIIA, FcγRIIB, and FcγRIIIB). These data indicate that destabilization of the glycan-protein interactions, rather than increased galactosylation and sialylation, modifies the Fc conformation(s) relevant for FcγR binding. Engineering of the protein-carbohydrate interface thus provides an independent parameter in the engineering of Fc effector functions and a route to the synthesis of new classes of Fc domain with novel combinations of affinities for activatory and inhibitory Fc receptors.
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Affiliation(s)
- Xiaojie Yu
- Oxford
Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1
3QU, United Kingdom
| | - Kavitha Baruah
- Oxford
Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1
3QU, United Kingdom
| | - David
J. Harvey
- Oxford
Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1
3QU, United Kingdom
| | - Snezana Vasiljevic
- Oxford
Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1
3QU, United Kingdom
| | - Dominic S. Alonzi
- Oxford
Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1
3QU, United Kingdom
| | - Byeong-Doo Song
- Scripps Korea Antibody
Institute, 192-1 Hyoja-dong, Chuncheon, Gangwon 200-701,
Korea
| | - Matthew
K. Higgins
- Oxford
Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1
3QU, United Kingdom
| | - Thomas A. Bowden
- Division of Structural
Biology, University of Oxford, Wellcome
Trust Centre for Human
Genetics, Roosevelt Drive, Oxford OX3 7BN, United Kingdom
| | - Christopher N. Scanlan
- Oxford
Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1
3QU, United Kingdom
| | - Max Crispin
- Oxford
Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1
3QU, United Kingdom
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39
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IgG2 Fc structure and the dynamic features of the IgG CH2-CH3 interface. Mol Immunol 2013; 56:131-9. [PMID: 23628091 DOI: 10.1016/j.molimm.2013.03.018] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 03/18/2013] [Accepted: 03/23/2013] [Indexed: 11/21/2022]
Abstract
The analyses of two human IgG2 Fc structures, determined in different crystal forms, and the comparison with IgG1 Fc structures reveals molecular features that are involved in accommodating and stabilizing structural conformations. In the IgG2 Fc structures relative positions of the CH2 domains with respect to the CH3 domains vary significantly from those observed for IgG1 Fc structures in similar unit cells. The analysis reveals that the movement of the CH2 domain in all of the Fc structures results from a pivoting around a highly conserved ball-and-socket-like joint in which the CH2 L251 side chain (the ball) interacts with a pocket (the socket) formed by CH3 M428, H429, E430, and H435. Despite the change in positioning of the CH2 and CH3 domains, conserved hydrogen bonds and electrostatic interactions are retained, stabilizing the Fc domain interface. In the high resolution IgG2 and IgG1 Fc structures the position and number of water molecules, and water networks bridging the two domains differ significantly because of the difference in positions of CH2 relative to CH3. At the domain interface, only CH2 T339 in IgG2 differs from alanine found in IgG1 and IgG4. This residue's side chain influences the water structure at the interface by interacting either directly or through a bridging water molecule with D376 in the CH3 BC loop. Thus, the analyses of the IgG2 Fc structures and their comparisons with IgG1 Fc structures reveals similar, but distinctly different dynamic CH2-CH3 interfaces that can accommodate a wide range of CH2-CH3 conformations, that in conjunction with the amino acid residues in the hinge region, may influence FcγR effector function profiles.
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Bolton GR, Ackerman ME, Boesch AW. Separation of nonfucosylated antibodies with immobilized FcγRIII receptors. Biotechnol Prog 2013; 29:825-8. [PMID: 23554380 DOI: 10.1002/btpr.1717] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 02/22/2013] [Accepted: 02/22/2013] [Indexed: 11/11/2022]
Abstract
Post-translational modifications can dramatically impact protein activity, but identifying such structure:function relationships, as well as capitalizing on functionally enhanced variants, is a significant challenge. Here, affinity chromatography resins that contained immobilized FcγRIII receptors were used to enrich nonfucosylated antibodies 6- to 9-fold, offering what may be a tractable method for both the identification of post-translational modifications that affect function, as well as a means to enrich variants with enhanced activity.
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Affiliation(s)
- Glen R Bolton
- Process Biochemistry, Biogen Idec, Cambridge, MA, 02142, USA
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Effector Properties and Glycosylation Patterns of Recombinant Human Anti-D-IgG1 Antibodies Produced by Human PER.C6® Cells. Bull Exp Biol Med 2012; 154:245-9. [DOI: 10.1007/s10517-012-1923-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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42
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Bowden TA, Baruah K, Coles CH, Harvey DJ, Yu X, Song BD, Stuart DI, Aricescu AR, Scanlan CN, Jones EY, Crispin M. Chemical and structural analysis of an antibody folding intermediate trapped during glycan biosynthesis. J Am Chem Soc 2012; 134:17554-63. [PMID: 23025485 PMCID: PMC3593610 DOI: 10.1021/ja306068g] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
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Human IgG Fc glycosylation modulates immunological effector
functions
such as antibody-dependent cellular cytotoxicity and phagocytosis.
Engineering of Fc glycans therefore enables fine-tuning of the therapeutic
properties of monoclonal antibodies. The N-linked glycans of Fc are
typically complex-type, forming a network of noncovalent interactions
along the protein surface of the Cγ2 domain. Here, we manipulate
the mammalian glycan-processing pathway to trap IgG1 Fc at sequential
stages of maturation, from oligomannose- to hybrid- to complex-type
glycans, and show that the Fc is structurally stabilized following
the transition of glycans from their hybrid- to complex-type state.
X-ray crystallographic analysis of this hybrid-type intermediate reveals
that N-linked glycans undergo conformational changes upon maturation,
including a flip within the trimannosyl core. Our crystal structure
of this intermediate reveals a molecular basis for antibody biogenesis
and provides a template for the structure-guided engineering of the
protein–glycan interface of therapeutic antibodies.
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Affiliation(s)
- Thomas A Bowden
- Division of Structural Biology, University of Oxford, Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, United Kingdom.
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43
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Huang W, Giddens J, Fan SQ, Toonstra C, Wang LX. Chemoenzymatic glycoengineering of intact IgG antibodies for gain of functions. J Am Chem Soc 2012; 134:12308-18. [PMID: 22747414 DOI: 10.1021/ja3051266] [Citation(s) in RCA: 230] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The fine structures of Fc N-glycans can modulate the effector functions of IgG antibodies. It has been demonstrated that lack of the core fucose on the Fc N-glycans leads to drastic enhancement of antibody-dependent cellular cytotoxicity (ADCC), while terminal α2,6-sialylation of Fc glycan plays a critical role for the anti-inflammatory activity of human intravenous immunoglobulin (IVIG). We describe in this paper a highly efficient chemoenzymatic method for site-selective Fc glycoengineering of intact monoclonal antibody and IVIG. Two new glycosynthase mutants (EndoS-D233A and D233Q) were generated by site-directed mutagenesis of EndoS (an endoglycosidase from Streptococcus pyogenes ) and were found to be capable of efficiently transferring predefined N-glycans from corresponding glycan oxazolines to the Fc-deglycosylated intact IgGs without product hydrolysis. As a model study, rituximab (a therapeutic monoclonal antibody) was successfully transformed from mixtures of G0F, G1F, and G2F glycoforms to well-defined homogeneous glycoforms, including a fully sialylated (S2G2F) glycoform that may gain anti-inflammatory activity, a nonfucosylated G2 glycoform that showed significantly enhanced FcγIIIa receptor-binding activity, and an azido-tagged glycoform that can be further transformed into other glycoforms. We also found that EndoS could selectively remove the Fc N-glycans in the presence of FAB glycosylation. This finding, coupled with the remarkable transglycosylation activity of the EndoS glycosynthase mutants, permitted a highly selective glycoengineering of the IVIG's Fc glycans into a fully sialylated Fc glycoform, which may possess significantly enhanced anti-inflammatory activity. The glycoengineering approach described here provides a general platform to modulate the effector functions of IgG antibodies, enabling the optimization of therapeutic efficacy and gain of new functions of monoclonal antibodies and IVIG.
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Affiliation(s)
- Wei Huang
- Institute of Human Virology and Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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Nagae M, Yamaguchi Y. Function and 3D structure of the N-glycans on glycoproteins. Int J Mol Sci 2012; 13:8398-8429. [PMID: 22942711 PMCID: PMC3430242 DOI: 10.3390/ijms13078398] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 06/28/2012] [Accepted: 06/18/2012] [Indexed: 12/17/2022] Open
Abstract
Glycosylation is one of the most common post-translational modifications in eukaryotic cells and plays important roles in many biological processes, such as the immune response and protein quality control systems. It has been notoriously difficult to study glycoproteins by X-ray crystallography since the glycan moieties usually have a heterogeneous chemical structure and conformation, and are often mobile. Nonetheless, recent technical advances in glycoprotein crystallography have accelerated the accumulation of 3D structural information. Statistical analysis of “snapshots” of glycoproteins can provide clues to understanding their structural and dynamic aspects. In this review, we provide an overview of crystallographic analyses of glycoproteins, in which electron density of the glycan moiety is clearly observed. These well-defined N-glycan structures are in most cases attributed to carbohydrate-protein and/or carbohydrate-carbohydrate interactions and may function as “molecular glue” to help stabilize inter- and intra-molecular interactions. However, the more mobile N-glycans on cell surface receptors, the electron density of which is usually missing on X-ray crystallography, seem to guide the partner ligand to its binding site and prevent irregular protein aggregation by covering oligomerization sites away from the ligand-binding site.
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Affiliation(s)
| | - Yoshiki Yamaguchi
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +81-48-467-9619; Fax: +81-48-467-9620
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45
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Selective deactivation of serum IgG: a general strategy for the enhancement of monoclonal antibody receptor interactions. J Mol Biol 2012; 420:1-7. [PMID: 22484364 PMCID: PMC3437440 DOI: 10.1016/j.jmb.2012.04.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 03/09/2012] [Accepted: 04/03/2012] [Indexed: 01/07/2023]
Abstract
Serum IgG is a potent inhibitor of monoclonal antibody (mAb) binding to the cell-surface Fcγ receptors (FcγRs), which mediate cytotoxic and phagocytic effector functions. Here, we show that this competition can be eliminated, selectively, by the introduction to serum of (i) an enzyme that displaces Fc from FcγRs and (ii) a modification present in the therapeutic mAb that renders it resistant to that enzyme. Specifically, we show that (i) EndoS (endoglycosidase S) cleaves only complex-type glycans of the type found on IgG but (ii) is inactive against an engineered IgG Fc with oligomannose-type glycans. EndoS thus reduces FcγR binding of serum IgG, but not that of engineered mAb. Introduction of both the engineered mAb and endoglycosidase in serum leads to a dramatic increase in FcγR binding compared to the introduction of mAb in serum alone. Antibody receptor refocusing is a general technique for boosting the effector signal of therapeutic antibodies.
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46
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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.
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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
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Affiliation(s)
- Ryan M Schmaltz
- The Department of Chemistry and Skaggs Institute for Chemical Biology, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
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48
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Harvey DJ, Sobott F, Crispin M, Wrobel A, Bonomelli C, Vasiljevic S, Scanlan CN, Scarff CA, Thalassinos K, Scrivens JH. Ion mobility mass spectrometry for extracting spectra of N-glycans directly from incubation mixtures following glycan release: application to glycans from engineered glycoforms of intact, folded HIV gp120. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2011; 22:568-81. [PMID: 21472575 DOI: 10.1007/s13361-010-0053-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 10/15/2010] [Accepted: 12/07/2010] [Indexed: 05/16/2023]
Abstract
The analysis of glycosylation from native biological sources is often frustrated by the low abundances of available material. Here, ion mobility combined with electrospray ionization mass spectrometry have been used to extract the spectra of N-glycans released with PNGase F from a serial titration of recombinantly expressed envelope glycoprotein, gp120, from the human immunodeficiency virus (HIV). Analysis was also performed on gp120 expressed in the α-mannosidase inhibitor, and in a matched mammalian cell line deficient in GlcNAc transferase I. Without ion mobility separation, ESI spectra frequently contained no observable ions from the glycans whereas ions from other compounds such as detergents and residual buffer salts were abundant. After ion mobility separation on a Waters T-wave ion mobility mass spectrometer, the N-glycans fell into a unique region of the ion mobility/m/z plot allowing their profiles to be extracted with good signal:noise ratios. This method allowed N-glycan profiles to be extracted from crude incubation mixtures with no clean-up even in the presence of surfactants such as NP40. Furthermore, this technique allowed clear profiles to be obtained from sub-microgram amounts of glycoprotein. Glycan profiles were similar to those generated by MALDI-TOF MS although they were more susceptible to double charging and fragmentation. Structural analysis could be accomplished by MS/MS experiments in either positive or negative ion mode but negative ion mode gave the most informative spectra and provided a reliable approach to the analysis of glycans from small amounts of glycoprotein.
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Affiliation(s)
- David J Harvey
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
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50
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Dimeric architecture of the Hendra virus attachment glycoprotein: evidence for a conserved mode of assembly. J Virol 2010; 84:6208-17. [PMID: 20375167 PMCID: PMC2876662 DOI: 10.1128/jvi.00317-10] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Hendra virus is a negative-sense single-stranded RNA virus within the Paramyxoviridae family which, together with Nipah virus, forms the Henipavirus genus. Infection with bat-borne Hendra virus leads to a disease with high mortality rates in humans. We determined the crystal structure of the unliganded six-bladed beta-propeller domain and compared it to the previously reported structure of Hendra virus attachment glycoprotein (HeV-G) in complex with its cellular receptor, ephrin-B2. As observed for the related unliganded Nipah virus structure, there is plasticity in the Glu579-Pro590 and Lys236-Ala245 ephrin-binding loops prior to receptor engagement. These data reveal that henipaviral attachment glycoproteins undergo common structural transitions upon receptor binding and further define the structural template for antihenipaviral drug design. Our analysis also provides experimental evidence for a dimeric arrangement of HeV-G that exhibits striking similarity to those observed in crystal structures of related paramyxovirus receptor-binding glycoproteins. The biological relevance of this dimer is further supported by the positional analysis of glycosylation sites from across the paramyxoviruses. In HeV-G, the sites lie away from the putative dimer interface and remain accessible to alpha-mannosidase processing on oligomerization. We therefore propose that the overall mode of dimer assembly is conserved for all paramyxoviruses; however, while the geometry of dimerization is rather closely similar for those viruses that bind flexible glycan receptors, significant (up to 60 degrees ) and different reconfigurations of the subunit packing (associated with a significant decrease in the size of the dimer interface) have accompanied the independent switching to high-affinity protein receptor binding in Hendra and measles viruses.
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