1
|
Choi J, Jeon Y, Roh Y, Jang J, Lee E, Villamante L, Kim M, Kwon MH. The dispensability of V H-V L pairing and the indispensability of V L domain integrity in the IgG1 secretion process. Front Mol Biosci 2024; 11:1346259. [PMID: 38756530 PMCID: PMC11096469 DOI: 10.3389/fmolb.2024.1346259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 04/09/2024] [Indexed: 05/18/2024] Open
Abstract
Introduction: The CH1 domain of IgG antibodies controls assembly and secretion, mediated by the molecular chaperone BiP via the endoplasmic reticulum protein quality control (ERQC) mechanism. However, it is not clear whether the variable domains are necessary for this process. Methods: Here, we generated IgG1 antibodies in which the V domain (VH and/or VL) was either removed or replaced, and then assessed expression, assembly, and secretion in HEK293 cells. Results: All Ig variants formed a covalent linkage between the Cγ1 and Cκ, were successfully secreted in an assembled form. Replacement of the cognate Vκ with a non-secretory pseudo Vκ (ψVκ) hindered secretion of individual or assembled secretion of neither heavy chains (HCs) nor light chains (LCs). The ψLC (ψVκ-Cκ) exhibited a less folded structure compared to the wild type (wt) LC, as evidenced by enhanced stable binding to the molecular chaperone BiP and susceptibility to proteolytic degradation. Molecular dynamics simulation demonstrated dramatic alterations in overall structure of ψFab (Fd-ψLC) from wt Fab. Discussion: These findings suggest that V domains do not initiate HC:LC assembly and secretion; instead, the critical factor governing IgG assembly and secretion is the CH-CL pairing. Additionally, the structural integrity of the VL domain is crucial for IgG secretion. These data offer valuable insight into the design of bioactive molecules based on an IgG backbone.
Collapse
Affiliation(s)
- Juho Choi
- Department of Biomedical Sciences, Graduate School, Ajou University, Suwon, Republic of Korea
| | - Yerin Jeon
- Department of Biomedical Sciences, Graduate School, Ajou University, Suwon, Republic of Korea
| | - Youngin Roh
- Department of Biomedical Sciences, Graduate School, Ajou University, Suwon, Republic of Korea
| | - Jeongyun Jang
- Department of Biomedical Sciences, Graduate School, Ajou University, Suwon, Republic of Korea
| | - Eunbin Lee
- Department of Biomedical Sciences, Graduate School, Ajou University, Suwon, Republic of Korea
| | - Luigie Villamante
- Department of Biomedical Sciences, Graduate School, Ajou University, Suwon, Republic of Korea
| | - Minjae Kim
- Department of Microbiology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Myung-Hee Kwon
- Department of Biomedical Sciences, Graduate School, Ajou University, Suwon, Republic of Korea
- Department of Microbiology, Ajou University School of Medicine, Suwon, Republic of Korea
| |
Collapse
|
2
|
Boyd LF, Jiang J, Ahmad J, Natarajan K, Margulies DH. Experimental Structures of Antibody/MHC-I Complexes Reveal Details of Epitopes Overlooked by Computational Prediction. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2024; 212:1366-1380. [PMID: 38456672 PMCID: PMC10982845 DOI: 10.4049/jimmunol.2300839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 02/14/2024] [Indexed: 03/09/2024]
Abstract
mAbs to MHC class I (MHC-I) molecules have proved to be crucial reagents for tissue typing and fundamental studies of immune recognition. To augment our understanding of epitopic sites seen by a set of anti-MHC-I mAb, we determined X-ray crystal structures of four complexes of anti-MHC-I Fabs bound to peptide/MHC-I/β2-microglobulin (pMHC-I). An anti-H2-Dd mAb, two anti-MHC-I α3 domain mAbs, and an anti-β2-microglobulin mAb bind pMHC-I at sites consistent with earlier mutational and functional experiments, and the structures explain allelomorph specificity. Comparison of the experimentally determined structures with computationally derived models using AlphaFold Multimer showed that although predictions of the individual pMHC-I heterodimers were quite acceptable, the computational models failed to properly identify the docking sites of the mAb on pMHC-I. The experimental and predicted structures provide insight into strengths and weaknesses of purely computational approaches and suggest areas that merit additional attention.
Collapse
Affiliation(s)
- Lisa F. Boyd
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD
| | - Jiansheng Jiang
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD
| | - Javeed Ahmad
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD
| | - Kannan Natarajan
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD
| | - David H. Margulies
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD
| |
Collapse
|
3
|
Boyd LF, Jiang J, Ahmad J, Natarajan K, Margulies DH. Experimental structures of antibody/MHC-I complexes reveal details of epitopes overlooked by computational prediction. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.01.569627. [PMID: 38106040 PMCID: PMC10723347 DOI: 10.1101/2023.12.01.569627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Monoclonal antibodies (mAb) to major histocompatibility complex class I (MHC-I) molecules have proved to be crucial reagents for tissue typing and fundamental studies of immune recognition. To augment our understanding of epitopic sites seen by a set of anti-MHC-I mAb, we determined X-ray crystal structures of four complexes of anti-MHC-I antigen-binding fragments (Fab) bound to peptide/MHC-I/β2m (pMHC-I). An anti-H2-Dd mAb, two anti-MHC-I α3 domain mAb, and an anti-β2-microglobulin (β2m) mAb bind pMHC-I at sites consistent with earlier mutational and functional experiments, and the structures explain allelomorph specificity. Comparison of the experimentally determined structures with computationally derived models using AlphaFold Multimer (AF-M) showed that although predictions of the individual pMHC-I heterodimers were quite acceptable, the computational models failed to properly identify the docking sites of the mAb on pMHC-I. The experimental and predicted structures provide insight into strengths and weaknesses of purely computational approaches and suggest areas that merit additional attention.
Collapse
Affiliation(s)
| | | | - Javeed Ahmad
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda MD, 20892-1892
| | - Kannan Natarajan
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda MD, 20892-1892
| | - David H. Margulies
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda MD, 20892-1892
| |
Collapse
|
4
|
Fernández-Quintero ML, Pomarici ND, Fischer ALM, Hoerschinger VJ, Kroell KB, Riccabona JR, Kamenik AS, Loeffler JR, Ferguson JA, Perrett HR, Liedl KR, Han J, Ward AB. Structure and Dynamics Guiding Design of Antibody Therapeutics and Vaccines. Antibodies (Basel) 2023; 12:67. [PMID: 37873864 PMCID: PMC10594513 DOI: 10.3390/antib12040067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 10/10/2023] [Accepted: 10/13/2023] [Indexed: 10/25/2023] Open
Abstract
Antibodies and other new antibody-like formats have emerged as one of the most rapidly growing classes of biotherapeutic proteins. Understanding the structural features that drive antibody function and, consequently, their molecular recognition is critical for engineering antibodies. Here, we present the structural architecture of conventional IgG antibodies alongside other formats. We emphasize the importance of considering antibodies as conformational ensembles in solution instead of focusing on single-static structures because their functions and properties are strongly governed by their dynamic nature. Thus, in this review, we provide an overview of the unique structural and dynamic characteristics of antibodies with respect to their antigen recognition, biophysical properties, and effector functions. We highlight the numerous technical advances in antibody structure prediction and design, enabled by the vast number of experimentally determined high-quality structures recorded with cryo-EM, NMR, and X-ray crystallography. Lastly, we assess antibody and vaccine design strategies in the context of structure and dynamics.
Collapse
Affiliation(s)
- Monica L. Fernández-Quintero
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Nancy D. Pomarici
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
| | - Anna-Lena M. Fischer
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
| | - Valentin J. Hoerschinger
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
| | - Katharina B. Kroell
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
| | - Jakob R. Riccabona
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
| | - Anna S. Kamenik
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
| | - Johannes R. Loeffler
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - James A. Ferguson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Hailee R. Perrett
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Klaus R. Liedl
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
| | - Julianna Han
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Andrew B. Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| |
Collapse
|
5
|
Liu ML, Chen ZJ, Huang XQ, Wang H, Zhao JL, Shen YD, Luo L, Wen XW, Hammock B, Xu ZL. A bispecific nanobody with high sensitivity/efficiency for simultaneous determination of carbaryl and its metabolite 1-naphthol in the soil and rice samples. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 335:122265. [PMID: 37517641 PMCID: PMC10529271 DOI: 10.1016/j.envpol.2023.122265] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/24/2023] [Accepted: 07/25/2023] [Indexed: 08/01/2023]
Abstract
The simultaneous determination of carbaryl and its metabolite 1-naphthol is essential for risk assessment of pesticide exposure in agricultural and environmental samples. Herein, several bispecific nanobodies (BsNbs) with different lengths of hydrophilic linkers and junction sites were prepared and characterized for the simultaneous recognition of carbaryl and its metabolite 1-naphthol. It was found that the affinity of BsNbs to the analytes could be regulated by controlling linker length and linking terminal. Additionally, molecular simulation revealed that linker lengths affected the conformation of BsNbs, leading to alteration in sensitivity. The BsNb with G4S linker, named G4S-C-N-VHH, showing good thermal stability and sensitivity was used to develop a bispecific indirect competitive enzyme-linked immunosorbent assay (Bic-ELISA). The assay demonstrated a limit of detection of 0.8 ng/mL for carbaryl and 0.4 ng/mL for 1-naphthol in buffer system. Good recoveries from soil and rice samples were obtained, ranging from 80.0% to 112.7% (carbaryl) and 76.5%-110.8% (1-naphthol), respectively. Taken together, this study firstly provided a BsNb with high sensitivity and efficiency against environmental pesticide and its metabolite, and firstly used molecular dynamics simulation to explore the influence of linker on recognition. The results are valuable for the application of immunoassay with high efficiency in the fields of environment and agriculture.
Collapse
Affiliation(s)
- Min-Ling Liu
- Guangdong Provincial Key Laboratory of Food Quality and Safety / Research Center for Green Development of Agriculture, South China Agricultural University, Guangzhou, 510642, China
| | - Zi-Jian Chen
- Guangdong Provincial Key Laboratory of Food Quality and Safety / Research Center for Green Development of Agriculture, South China Agricultural University, Guangzhou, 510642, China; Laboratory of Quality & Safety Risk Assessment for Agro-products (Zhaoqing), Ministry of Agriculture and Rural Affairs, School of Food and Pharmaceutical Engineering, Zhaoqing University, Zhaoqing, 526061, China
| | - Xiao-Qing Huang
- Guangzhou Institute of Food Inspection, Guangzhou, 510410, China
| | - Hong Wang
- Guangdong Provincial Key Laboratory of Food Quality and Safety / Research Center for Green Development of Agriculture, South China Agricultural University, Guangzhou, 510642, China
| | - Jin-Li Zhao
- Guangzhou Institute of Food Inspection, Guangzhou, 510410, China
| | - Yu-Dong Shen
- Guangdong Provincial Key Laboratory of Food Quality and Safety / Research Center for Green Development of Agriculture, South China Agricultural University, Guangzhou, 510642, China
| | - Lin Luo
- Guangdong Provincial Key Laboratory of Food Quality and Safety / Research Center for Green Development of Agriculture, South China Agricultural University, Guangzhou, 510642, China
| | - Xiao-Wei Wen
- Guangdong Provincial Key Laboratory of Food Quality and Safety / Research Center for Green Development of Agriculture, South China Agricultural University, Guangzhou, 510642, China
| | - Bruce Hammock
- Department of Entomology and UCD Comprehensive Cancer Center, University of California, Davis, CA, 95616, United States
| | - Zhen-Lin Xu
- Guangdong Provincial Key Laboratory of Food Quality and Safety / Research Center for Green Development of Agriculture, South China Agricultural University, Guangzhou, 510642, China.
| |
Collapse
|
6
|
Structural mechanism of Fab domain dissociation as a measure of interface stability. J Comput Aided Mol Des 2023; 37:201-215. [PMID: 36918473 PMCID: PMC10049950 DOI: 10.1007/s10822-023-00501-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 02/23/2023] [Indexed: 03/16/2023]
Abstract
Therapeutic antibodies should not only recognize antigens specifically, but also need to be free from developability issues, such as poor stability. Thus, the mechanistic understanding and characterization of stability are critical determinants for rational antibody design. In this study, we use molecular dynamics simulations to investigate the melting process of 16 antigen binding fragments (Fabs). We describe the Fab dissociation mechanisms, showing a separation in the VH-VL and in the CH1-CL domains. We found that the depths of the minima in the free energy curve, corresponding to the bound states, correlate with the experimentally determined melting temperatures. Additionally, we provide a detailed structural description of the dissociation mechanism and identify key interactions in the CDR loops and in the CH1-CL interface that contribute to stabilization. The dissociation of the VH-VL or CH1-CL domains can be represented by conformational changes in the bend angles between the domains. Our findings elucidate the melting process of antigen binding fragments and highlight critical residues in both the variable and constant domains, which are also strongly germline dependent. Thus, our proposed mechanisms have broad implications in the development and design of new and more stable antigen binding fragments.
Collapse
|