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Pirazzini M, Grinzato A, Corti D, Barbieri S, Leka O, Vallese F, Tonellato M, Silacci-Fregni C, Piccoli L, Kandiah E, Schiavo G, Zanotti G, Lanzavecchia A, Montecucco C. Exceptionally potent human monoclonal antibodies are effective for prophylaxis and treatment of tetanus in mice. J Clin Invest 2021; 131:151676. [PMID: 34618682 DOI: 10.1172/jci151676] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 09/28/2021] [Indexed: 01/15/2023] Open
Abstract
We used human monoclonal antibodies (humAbs) to study the mechanism of neuron intoxication by tetanus neurotoxin and to evaluate these antibodies as a safe preventive and therapeutic substitute for hyperimmune sera to treat tetanus in mice. By screening memory B cells from immune donors, we selected 2 tetanus neurotoxin-specific mAbs with exceptionally high neutralizing activities and extensively characterized them both structurally and functionally. We found that these antibodies interfered with the binding and translocation of the neurotoxin into neurons by interacting with 2 epitopes, whose identification pinpoints crucial events in the cellular pathogenesis of tetanus. Our observations explain the neutralization ability of these antibodies, which we found to be exceptionally potent in preventing experimental tetanus when injected into mice long before the toxin. Moreover, their Fab derivatives neutralized tetanus neurotoxin in post-exposure experiments, suggesting their potential for therapeutic use via intrathecal injection. As such, we believe these humAbs, as well as their Fab derivatives, meet the requirements to be considered for prophylactic and therapeutic use in human tetanus and are ready for clinical trials.
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Affiliation(s)
- Marco Pirazzini
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | | | | | - Oneda Leka
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Francesca Vallese
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Marika Tonellato
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Chiara Silacci-Fregni
- Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Luca Piccoli
- Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland
| | | | - Giampietro Schiavo
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology and.,UK Dementia Research Institute, University College London, London, United Kingdom
| | - Giuseppe Zanotti
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Antonio Lanzavecchia
- Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland.,Fondazione Istituto Nazionale Genetica Molecolare, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico di Milano, Milano, Italy
| | - Cesare Montecucco
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Institute of Neuroscience, National Research Council, Padova, Italy
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Fan X, Wang J, Zhang X, Yang Z, Zhang JC, Zhao L, Peng HL, Lei J, Wang HW. Single particle cryo-EM reconstruction of 52 kDa streptavidin at 3.2 Angstrom resolution. Nat Commun 2019; 10:2386. [PMID: 31160591 PMCID: PMC6546690 DOI: 10.1038/s41467-019-10368-w] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 05/06/2019] [Indexed: 11/09/2022] Open
Abstract
The fast development of single-particle cryogenic electron microscopy (cryo-EM) has made it more feasible to obtain the 3D structure of well-behaved macromolecules with a molecular weight higher than 300 kDa at ~3 Å resolution. However, it remains a challenge to obtain the high-resolution structures of molecules smaller than 200 kDa using single-particle cryo-EM. In this work, we apply the Cs-corrector-VPP-coupled cryo-EM to study the 52 kDa streptavidin (SA) protein supported on a thin layer of graphene and embedded in vitreous ice. We are able to solve both the apo-SA and biotin-bound SA structures at near-atomic resolution using single-particle cryo-EM. We demonstrate that the method has the potential to determine the structures of molecules as small as 39 kDa. It remains a challenge to obtain high-resolution structures of molecules smaller than 200 kDa using single particle cryo-EM. Here, the authors apply the Cs-corrector-VPP coupled cryo-EM and solve structures of the 52 kDa streptavidin (SA) protein at near-atomic resolution.
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Affiliation(s)
- Xiao Fan
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center of Biological Structures, School of Life Sciences, Tsinghua University, Beijing, 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jia Wang
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center of Biological Structures, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xing Zhang
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center of Biological Structures, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Zi Yang
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center of Biological Structures, School of Life Sciences, Tsinghua University, Beijing, 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jin-Can Zhang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Lingyun Zhao
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center of Biological Structures, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Hai-Lin Peng
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Jianlin Lei
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center of Biological Structures, School of Life Sciences, Tsinghua University, Beijing, 100084, China. .,Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing, 100084, China.
| | - Hong-Wei Wang
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center of Biological Structures, School of Life Sciences, Tsinghua University, Beijing, 100084, China. .,Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing, 100084, China.
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3
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Huang X, Sun S, Wang X, Fan F, Zhou Q, Lu S, Cao Y, Wang QW, Dong MQ, Yao J, Sui SF. Mechanistic insights into the SNARE complex disassembly. SCIENCE ADVANCES 2019; 5:eaau8164. [PMID: 30989110 PMCID: PMC6457932 DOI: 10.1126/sciadv.aau8164] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 02/19/2019] [Indexed: 05/16/2023]
Abstract
NSF (N-ethylmaleimide-sensitive factor) and α-SNAP (α-soluble NSF attachment protein) bind to the SNARE (soluble NSF attachment protein receptor) complex, the minimum machinery to mediate membrane fusion, to form a 20S complex, which disassembles the SNARE complex for reuse. We report the cryo-EM structures of the α-SNAP-SNARE subcomplex and the NSF-D1D2 domain in the 20S complex at 3.9- and 3.7-Å resolutions, respectively. Combined with the biochemical and electrophysiological analyses, we find that α-SNAPs use R116 through electrostatic interactions and L197 through hydrophobic interactions to apply force mainly on two positions of the VAMP protein to execute disassembly process. Furthermore, we define the interaction between the amino terminus of the SNARE helical bundle and the pore loop of the NSF-D1 domain and demonstrate its essential role as a potential anchor for SNARE complex disassembly. Our studies provide a rotation model of α-SNAP-mediated disassembly of the SNARE complex.
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Affiliation(s)
- Xuan Huang
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Shan Sun
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaojing Wang
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Fenghui Fan
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qiang Zhou
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Shan Lu
- National Institute of Biological Sciences, Beijing 102206, China
| | - Yong Cao
- National Institute of Biological Sciences, Beijing 102206, China
| | - Qiu-Wen Wang
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Meng-Qiu Dong
- National Institute of Biological Sciences, Beijing 102206, China
| | - Jun Yao
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Sen-Fang Sui
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Corresponding author.
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Kumar A, Plückthun A. In vivo assembly and large-scale purification of a GPCR - Gα fusion with Gβγ, and characterization of the active complex. PLoS One 2019; 14:e0210131. [PMID: 30620756 PMCID: PMC6324789 DOI: 10.1371/journal.pone.0210131] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 12/04/2018] [Indexed: 12/13/2022] Open
Abstract
G protein coupled receptors (GPCRs) are central players in recognizing a variety of stimuli to mediate diverse cellular responses. This myriad of functions is accomplished by their modular interactions with downstream intracellular transducers, such as heterotrimeric G proteins and arrestins. Assembling a specific GPCR-G protein pair as a purified complex for their structural and functional investigations remains a challenging task, however, because of the low affinity of the interaction. Here, we optimized fusion constructs of the Gα subunit of the heterotrimeric G protein and engineered versions of rat Neurotensin receptor 1 (NTR1), coexpressed and assembled in vivo with Gβ and Gγ. This was achieved by using the baculovirus-based MultiBac system. We thus generated a functional receptor-G protein fusion complex, which can be efficiently purified using ligand-based affinity chromatography on large scales. Additionally, we utilized a purification method based on a designed ankyrin repeat protein tightly binding to Green Fluorescent Protein (GFP-DARPin) that may be used as a generic approach for a large-scale purification of GPCR-G protein fusion complexes for which no ligands column can be generated. The purification methods described herein will support future studies that aim to understand the structural and functional framework of GPCR activation and signaling.
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Affiliation(s)
- Abhinav Kumar
- Department of Biochemistry, University of Zürich, Zürich, Switzerland
| | - Andreas Plückthun
- Department of Biochemistry, University of Zürich, Zürich, Switzerland
- * E-mail:
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Image processing for cryogenic transmission electron microscopy of symmetry-mismatched complexes. Biosci Rep 2018; 38:BSR20170203. [PMID: 29439140 PMCID: PMC5857907 DOI: 10.1042/bsr20170203] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 02/05/2018] [Accepted: 02/05/2018] [Indexed: 12/23/2022] Open
Abstract
Cryogenic transmission electron microscopy (cryo-TEM) is a high-resolution biological imaging method, whereby biological samples, such as purified proteins, macromolecular complexes, viral particles, organelles and cells, are embedded in vitreous ice preserving their native structures. Due to sensitivity of biological materials to the electron beam of the microscope, only relatively low electron doses can be applied during imaging. As a result, the signal arising from the structure of interest is overpowered by noise in the images. To increase the signal-to-noise ratio, different image processing-based strategies that aim at coherent averaging of signal have been devised. In such strategies, images are generally assumed to arise from multiple identical copies of the structure. Prior to averaging, the images must be grouped according to the view of the structure they represent and images representing the same view must be simultaneously aligned relatively to each other. For computational reconstruction of the 3D structure, images must contain different views of the original structure. Structures with multiple symmetry-related substructures are advantageous in averaging approaches because each image provides multiple views of the substructures. However, the symmetry assumption may be valid for only parts of the structure, leading to incoherent averaging of the other parts. Several image processing approaches have been adapted to tackle symmetry-mismatched substructures with increasing success. Such structures are ubiquitous in nature and further computational method development is needed to understanding their biological functions.
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