1
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Sabsay KR, te Velthuis AJW. Negative and ambisense RNA virus ribonucleocapsids: more than protective armor. Microbiol Mol Biol Rev 2023; 87:e0008223. [PMID: 37750733 PMCID: PMC10732063 DOI: 10.1128/mmbr.00082-23] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023] Open
Abstract
SUMMARYNegative and ambisense RNA viruses are the causative agents of important human diseases such as influenza, measles, Lassa fever, and Ebola hemorrhagic fever. The viral genome of these RNA viruses consists of one or more single-stranded RNA molecules that are encapsidated by viral nucleocapsid proteins to form a ribonucleoprotein complex (RNP). This RNP acts as protection, as a scaffold for RNA folding, and as the context for viral replication and transcription by a viral RNA polymerase. However, the roles of the viral nucleoproteins extend beyond these functions during the viral infection cycle. Recent advances in structural biology techniques and analysis methods have provided new insights into the formation, function, dynamics, and evolution of negative sense virus nucleocapsid proteins, as well as the role that they play in host innate immune responses against viral infection. In this review, we discuss the various roles of nucleocapsid proteins, both in the context of RNPs and in RNA-free states, as well as the open questions that remain.
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Affiliation(s)
- Kimberly R. Sabsay
- Lewis Thomas Laboratory, Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, USA
| | - Aartjan J. W. te Velthuis
- Lewis Thomas Laboratory, Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
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2
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Gonnin L, Desfosses A, Bacia-Verloop M, Chevret D, Galloux M, Éléouët JF, Gutsche I. Structural landscape of the respiratory syncytial virus nucleocapsids. Nat Commun 2023; 14:5732. [PMID: 37714861 PMCID: PMC10504348 DOI: 10.1038/s41467-023-41439-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 09/01/2023] [Indexed: 09/17/2023] Open
Abstract
Human Respiratory Syncytial Virus (HRSV) is a prevalent cause of severe respiratory infections in children and the elderly. The helical HRSV nucleocapsid is a template for the viral RNA synthesis and a scaffold for the virion assembly. This cryo-electron microscopy analysis reveals the non-canonical arrangement of the HRSV nucleocapsid helix, composed of 16 nucleoproteins per asymmetric unit, and the resulting systematic variations in the RNA accessibility. We demonstrate that this unique helical symmetry originates from longitudinal interactions by the C-terminal arm of the HRSV nucleoprotein. We explore the polymorphism of the nucleocapsid-like assemblies, report five structures of the full-length particles and two alternative arrangements formed by a C-terminally truncated nucleoprotein mutant, and demonstrate the functional importance of the identified longitudinal interfaces. We put all these findings in the context of the HRSV RNA synthesis machinery and delineate the structural basis for its further investigation.
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Affiliation(s)
- Lorène Gonnin
- Institut de Biologie Structurale, Univ Grenoble Alpes, CEA, CNRS, IBS, 71 Avenue des martyrs, F-38044, Grenoble, France
- VIM, Paris-Saclay University, INRAE, 78350, Jouy-en-Josas, France
| | - Ambroise Desfosses
- Institut de Biologie Structurale, Univ Grenoble Alpes, CEA, CNRS, IBS, 71 Avenue des martyrs, F-38044, Grenoble, France.
| | - Maria Bacia-Verloop
- Institut de Biologie Structurale, Univ Grenoble Alpes, CEA, CNRS, IBS, 71 Avenue des martyrs, F-38044, Grenoble, France
| | - Didier Chevret
- VIM, Paris-Saclay University, INRAE, 78350, Jouy-en-Josas, France
| | - Marie Galloux
- VIM, Paris-Saclay University, INRAE, 78350, Jouy-en-Josas, France
| | | | - Irina Gutsche
- Institut de Biologie Structurale, Univ Grenoble Alpes, CEA, CNRS, IBS, 71 Avenue des martyrs, F-38044, Grenoble, France.
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3
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Wang Y, Zhang C, Luo Y, Ling X, Luo B, Jia G, Su D, Dong H, Su Z. Cryo-EM structure of the nucleocapsid-like assembly of respiratory syncytial virus. Signal Transduct Target Ther 2023; 8:323. [PMID: 37607909 PMCID: PMC10444854 DOI: 10.1038/s41392-023-01602-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 06/08/2023] [Accepted: 08/13/2023] [Indexed: 08/24/2023] Open
Abstract
Respiratory syncytial virus (RSV) is a nonsegmented, negative strand RNA virus that has caused severe lower respiratory tract infections of high mortality rates in infants and the elderly, yet no effective vaccine or antiviral therapy is available. The RSV genome encodes the nucleoprotein (N) that forms helical assembly to encapsulate and protect the RNA genome from degradation, and to serve as a template for transcription and replication. Previous crystal structure revealed a decameric ring architecture of N in complex with the cellular RNA (N-RNA) of 70 nucleotides (70-nt), whereas cryo-ET reconstruction revealed a low-resolution left-handed filament, in which the crystal monomer structure was docked with the helical symmetry applied to simulate a nucleocapsid-like assembly of RSV. However, the molecular details of RSV nucleocapsid assembly remain unknown, which continue to limit our complete understanding of the critical interactions involved in the nucleocapsid and antiviral development that may target this essential process during the viral life cycle. Here we resolve the near-atomic cryo-EM structure of RSV N-RNA that represents roughly one turn of the helical assembly that unveils critical interaction interfaces of RSV nucleocapsid and may facilitate development of RSV antiviral therapy.
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Affiliation(s)
- Yan Wang
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, Department of Geriatrics and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan, 610044, China
| | - Chong Zhang
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, Department of Geriatrics and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan, 610044, China
| | - Yongbo Luo
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, Department of Geriatrics and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan, 610044, China
| | - Xiaobin Ling
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, Department of Geriatrics and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan, 610044, China
| | - Bingnan Luo
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, Department of Geriatrics and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan, 610044, China
| | - Guowen Jia
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, Department of Geriatrics and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan, 610044, China
| | - Dan Su
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, Department of Geriatrics and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan, 610044, China
| | - Haohao Dong
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, Department of Geriatrics and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan, 610044, China
| | - Zhaoming Su
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, Department of Geriatrics and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan, 610044, China.
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4
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Salgueiro M, Camporeale G, Visentin A, Aran M, Pellizza L, Esperante SA, Corbat A, Grecco H, Sousa B, Esperón R, Borkosky SS, de Prat-Gay G. Molten Globule Driven and Self-downmodulated Phase Separation of a Viral Factory Scaffold. J Mol Biol 2023; 435:168153. [PMID: 37210029 DOI: 10.1016/j.jmb.2023.168153] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 05/09/2023] [Accepted: 05/12/2023] [Indexed: 05/22/2023]
Abstract
Viral factories of liquid-like nature serve as sites for transcription and replication in most viruses. The respiratory syncytial virus factories include replication proteins, brought together by the phosphoprotein (P) RNA polymerase cofactor, present across non-segmented negative stranded RNA viruses. Homotypic liquid-liquid phase separation of RSV-P is governed by an α-helical molten globule domain, and strongly self-downmodulated by adjacent sequences. Condensation of P with the nucleoprotein N is stoichiometrically tuned, defining aggregate-droplet and droplet-dissolution boundaries. Time course analysis show small N-P nuclei gradually coalescing into large granules in transfected cells. This behavior is recapitulated in infection, with small puncta evolving to large viral factories, strongly suggesting that P-N nucleation-condensation sequentially drives viral factories. Thus, the tendency of P to undergo phase separation is moderate and latent in the full-length protein but unleashed in the presence of N or when neighboring disordered sequences are deleted. This, together with its capacity to rescue nucleoprotein-RNA aggregates suggests a role as a "solvent-protein".
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Affiliation(s)
- Mariano Salgueiro
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA) CONICET, Buenos Aires, Argentina
| | - Gabriela Camporeale
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA) CONICET, Buenos Aires, Argentina
| | - Araceli Visentin
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA) CONICET, Buenos Aires, Argentina
| | - Martin Aran
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA) CONICET, Buenos Aires, Argentina
| | - Leonardo Pellizza
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA) CONICET, Buenos Aires, Argentina
| | | | - Agustín Corbat
- Facultad de Ciencias Exactas y Naturales (FCEN), Universidad de Buenos Aires, and IFIBA, CONICET, Buenos Aires, Argentina
| | - Hernán Grecco
- Facultad de Ciencias Exactas y Naturales (FCEN), Universidad de Buenos Aires, and IFIBA, CONICET, Buenos Aires, Argentina
| | - Belén Sousa
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA) CONICET, Buenos Aires, Argentina
| | - Ramiro Esperón
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA) CONICET, Buenos Aires, Argentina
| | - Silvia S Borkosky
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA) CONICET, Buenos Aires, Argentina
| | - Gonzalo de Prat-Gay
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA) CONICET, Buenos Aires, Argentina.
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5
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Wilkins D, Yuan Y, Chang Y, Aksyuk AA, Núñez BS, Wählby-Hamrén U, Zhang T, Abram ME, Leach A, Villafana T, Esser MT. Durability of neutralizing RSV antibodies following nirsevimab administration and elicitation of the natural immune response to RSV infection in infants. Nat Med 2023; 29:1172-1179. [PMID: 37095249 PMCID: PMC10202809 DOI: 10.1038/s41591-023-02316-5] [Citation(s) in RCA: 59] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 03/20/2023] [Indexed: 04/26/2023]
Abstract
Nirsevimab is an extended half-life monoclonal antibody specific for the prefusion conformation of the respiratory syncytial virus (RSV) F protein, which has been studied in preterm and full-term infants in the phase 2b and phase 3 MELODY trials. We analyzed serum samples collected from 2,143 infants during these studies to characterize baseline levels of RSV-specific immunoglobulin G antibodies and neutralizing antibodies (NAbs), duration of RSV NAb levels following nirsevimab administration, the risk of RSV exposure during the first year of life and the infant's adaptive immune response to RSV following nirsevimab administration. Baseline RSV antibody levels varied widely; consistent with reports that maternal antibodies are transferred late in the third trimester, preterm infants had lower baseline RSV antibody levels than full-term infants. Nirsevimab recipients had RSV NAb levels >140-fold higher than baseline at day 31 and remained >50-fold higher at day 151 and >7-fold higher at day 361. Similar seroresponse rates to the postfusion form of RSV F protein in nirsevimab recipients (68-69%) compared with placebo recipients (63-70%; not statistically significant) suggest that while nirsevimab protects from RSV disease, it still allows an active immune response. In summary, nirsevimab provided sustained, high levels of NAb throughout an infant's first RSV season and prevented RSV disease while allowing the development of an immune response to RSV.
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Affiliation(s)
- Deidre Wilkins
- Translational Medicine, Vaccines & Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA.
| | - Yuan Yuan
- Translational Medicine, Vaccines & Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Yue Chang
- Translational Medicine, Vaccines & Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Anastasia A Aksyuk
- Translational Medicine, Vaccines & Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Beatriz Seoane Núñez
- Biometrics, Vaccines & Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Madrid, Spain
| | - Ulrika Wählby-Hamrén
- Clinical Pharmacology & Quantitative Pharmacology, R&D, AstraZeneca, Gothenburg, Sweden
| | - Tianhui Zhang
- Data Sciences and Quantitative Biology, R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Michael E Abram
- Translational Medicine, Vaccines & Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Amanda Leach
- Clinical Development, Vaccines & Immune Therapies, Biopharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Tonya Villafana
- Vaccines & Immune Therapies, Biopharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Mark T Esser
- Vaccines & Immune Therapies, Biopharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
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6
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Diethelm-Varela B, Soto JA, Riedel CA, Bueno SM, Kalergis AM. New Developments and Challenges in Antibody-Based Therapies for the Respiratory Syncytial Virus. Infect Drug Resist 2023; 16:2061-2074. [PMID: 37063935 PMCID: PMC10094422 DOI: 10.2147/idr.s379660] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 03/29/2023] [Indexed: 04/18/2023] Open
Abstract
Since the discovery of the human respiratory syncytial virus (hRSV), multiple research efforts have been conducted to develop vaccines and treatments capable of reducing the risk of severe disease, hospitalization, long-term sequelae, and death from this pathogen in susceptible populations. In this sense, therapies specifically directed against hRSV are mainly based on monoclonal and polyclonal antibodies such as intravenous IgG (IVIG)-RSV and the monoclonal antibody palivizumab. However, these therapies are associated with significant limitations, including the need for the recruitment of a high number of convalescent volunteers who donate blood to procure IVIG-RSV and the costs associated with the need for repeated administrations of palivizumab. These limitations render this product not cost-effective for populations other than high-risk patients. These problems have underscored that it is still necessary to identify new safe and effective therapies for human use. However, these new therapies must benefit from a comparatively cheap production cost and the opportunity to be available to the high-risk population and anyone who requires treatment. Here, we review the different antibodies used to prevent the pathology caused by hRSV infection, highlighting therapies currently approved for human use and their clinical value. Also, the new, most promising candidates based on preclinical studies and clinical trial results are revised.
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Affiliation(s)
- Benjamín Diethelm-Varela
- Millennium Institute of Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jorge A Soto
- Millennium Institute of Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Millennium Institute on Immunology and Immunotherapy, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Claudia A Riedel
- Millennium Institute on Immunology and Immunotherapy, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Susan M Bueno
- Millennium Institute of Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alexis M Kalergis
- Millennium Institute of Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
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7
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Conley MJ, Short JM, Burns AM, Streetley J, Hutchings J, Bakker SE, Power BJ, Jaffery H, Haney J, Zanetti G, Murcia PR, Stewart M, Fearns R, Vijayakrishnan S, Bhella D. Helical ordering of envelope-associated proteins and glycoproteins in respiratory syncytial virus. EMBO J 2022; 41:e109728. [PMID: 34935163 PMCID: PMC8804925 DOI: 10.15252/embj.2021109728] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 12/01/2021] [Accepted: 12/03/2021] [Indexed: 12/20/2022] Open
Abstract
Human respiratory syncytial virus (RSV) causes severe respiratory illness in children and the elderly. Here, using cryogenic electron microscopy and tomography combined with computational image analysis and three-dimensional reconstruction, we show that there is extensive helical ordering of the envelope-associated proteins and glycoproteins of RSV filamentous virions. We calculated a 16 Å resolution sub-tomogram average of the matrix protein (M) layer that forms an endoskeleton below the viral envelope. These data define a helical lattice of M-dimers, showing how M is oriented relative to the viral envelope. Glycoproteins that stud the viral envelope were also found to be helically ordered, a property that was coordinated by the M-layer. Furthermore, envelope glycoproteins clustered in pairs, a feature that may have implications for the conformation of fusion (F) glycoprotein epitopes that are the principal target for vaccine and monoclonal antibody development. We also report the presence, in authentic virus infections, of N-RNA rings packaged within RSV virions. These data provide molecular insight into the organisation of the virion and the mechanism of its assembly.
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Affiliation(s)
- Michaela J Conley
- Medical Research Council – University of Glasgow Centre for Virus ResearchGlasgowUK
| | - Judith M Short
- Medical Research Council Laboratory of Molecular BiologyCambridgeUK
| | - Andrew M Burns
- Medical Research Council – University of Glasgow Centre for Virus ResearchGlasgowUK
| | - James Streetley
- Medical Research Council – University of Glasgow Centre for Virus ResearchGlasgowUK
| | - Joshua Hutchings
- Department of Biological SciencesBirkbeck CollegeLondonUK
- Present address:
Division of Biological SciencesUniversity of California San DiegoLa JollaCAUSA
| | - Saskia E Bakker
- Medical Research Council – University of Glasgow Centre for Virus ResearchGlasgowUK
- Present address:
School of Life SciencesUniversity of WarwickCoventryUK
| | - B Joanne Power
- Medical Research Council – University of Glasgow Centre for Virus ResearchGlasgowUK
- Present address:
Department of Biochemistry and Molecular BiologyThe Huck Center for Malaria ResearchPennsylvania State UniversityUniversity ParkPAUSA
| | - Hussain Jaffery
- Medical Research Council – University of Glasgow Centre for Virus ResearchGlasgowUK
| | - Joanne Haney
- Medical Research Council – University of Glasgow Centre for Virus ResearchGlasgowUK
| | - Giulia Zanetti
- Department of Biological SciencesBirkbeck CollegeLondonUK
| | - Pablo R Murcia
- Medical Research Council – University of Glasgow Centre for Virus ResearchGlasgowUK
| | - Murray Stewart
- Medical Research Council Laboratory of Molecular BiologyCambridgeUK
| | - Rachel Fearns
- Department of MicrobiologyBoston University School of MedicineBostonMAUSA
- National Emerging Infectious Diseases LaboratoriesBoston UniversityBostonMAUSA
| | | | - David Bhella
- Medical Research Council – University of Glasgow Centre for Virus ResearchGlasgowUK
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8
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Gao Y, Cao D, Ahn HM, Swain A, Hill S, Ogilvie C, Kurien M, Rahmatullah T, Liang B. In vitro trackable assembly of RNA-specific nucleocapsids of the respiratory syncytial virus. J Biol Chem 2020. [DOI: 10.1016/s0021-9258(17)49942-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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9
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Gao Y, Cao D, Ahn HM, Swain A, Hill S, Ogilvie C, Kurien M, Rahmatullah T, Liang B. In vitro trackable assembly of RNA-specific nucleocapsids of the respiratory syncytial virus. J Biol Chem 2019; 295:883-895. [PMID: 31822560 PMCID: PMC6970927 DOI: 10.1074/jbc.ra119.011602] [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] [Received: 10/23/2019] [Revised: 11/26/2019] [Indexed: 12/25/2022] Open
Abstract
The templates for transcription and replication by respiratory syncytial virus (RSV) polymerase are helical nucleocapsids (NCs), formed by viral RNAs that are encapsidated by the nucleoprotein (N). Proper NC assembly is vital for RSV polymerase to engage the RNA template for RNA synthesis. Previous studies of NCs or nucleocapsid-like particles (NCLPs) from RSV and other nonsegmented negative-sense RNA viruses have provided insights into the overall NC architecture. However, in these studies, the RNAs were either random cellular RNAs or average viral genomic RNAs. An in-depth mechanistic understanding of NCs has been hampered by lack of an in vitro assay that can track NC or NCLP assembly. Here we established a protocol to obtain RNA-free N protein (N0) and successfully demonstrated the utility of a new assay for tracking assembly of N with RNA oligonucleotides into NCLPs. We discovered that the efficiency of the NCLP (N–RNA) assembly depends on the length and sequence of the RNA incorporated into NCLPs. This work provides a framework to generate purified N0 and incorporate it with RNA into NCLPs in a controllable manner. We anticipate that our assay for in vitro trackable assembly of RSV-specific nucleocapsids may enable in-depth mechanistic analyses of this process.
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Affiliation(s)
- Yunrong Gao
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Dongdong Cao
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Hyunjun Max Ahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Anshuman Swain
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Shaylan Hill
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Claire Ogilvie
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Matthew Kurien
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Taha Rahmatullah
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Bo Liang
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
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10
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Aljabr W, Armstrong S, Rickett NY, Pollakis G, Touzelet O, Cloutman-Green E, Matthews DA, Hiscox JA. High Resolution Analysis of Respiratory Syncytial Virus Infection In Vivo. Viruses 2019; 11:v11100926. [PMID: 31658630 PMCID: PMC6832471 DOI: 10.3390/v11100926] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 10/01/2019] [Accepted: 10/02/2019] [Indexed: 12/27/2022] Open
Abstract
Human respiratory syncytial virus (HRSV) is a major cause of pediatric infection and also causes disease in the elderly and those with underlying respiratory problems. There is no vaccine for HRSV and anti-viral therapeutics are not broadly applicable. To investigate the effect of HRSV biology in children, nasopharyngeal aspirates were taken from children with different viral loads and a combined high throughput RNAseq and label free quantitative proteomics approach was used to characterize the nucleic acid and proteins in these samples. HRSV proteins were identified in the nasopharyngeal aspirates from infected children, and their abundance correlated with viral load (Ct value), confirming HRSV infection. Analysis of the HRSV genome indicated that the children were infected with sub-group A virus and that minor variants in nucleotide frequency occurred in discrete clusters along the HRSV genome, and within a patient clustered distinctly within the glycoprotein gene. Data from the samples were binned into four groups; no-HRSV infection (control), high viral load (Ct < 20), medium viral load (Ct = 20-25), and low viral load (Ct > 25). Cellular proteins associated with the anti-viral response (e.g., ISG15) were identified in the nasopharyngeal aspirates and their abundance was correlated with viral load. These combined approaches have not been used before to study HRSV biology in vivo and can be readily applied to the study the variation of virus host interactions.
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Affiliation(s)
- Waleed Aljabr
- King Fahad Medical City, Research Center, 59046 Riyadh 11525, Saudi Arabia.
| | - Stuart Armstrong
- Institute of Infection and Global Health, University of Liverpool, Liverpool L3 5RF, UK.
- National Institute of Health Research, Health Protection Research Unit in Emerging and Zoonotic Infections, Liverpool L3 5RF, UK.
| | - Natasha Y Rickett
- Institute of Infection and Global Health, University of Liverpool, Liverpool L3 5RF, UK.
- National Institute of Health Research, Health Protection Research Unit in Emerging and Zoonotic Infections, Liverpool L3 5RF, UK.
| | - Georgios Pollakis
- Institute of Infection and Global Health, University of Liverpool, Liverpool L3 5RF, UK.
| | - Olivier Touzelet
- School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, Belfast BT9 7BL, UK.
| | | | - David A Matthews
- School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK.
| | - Julian A Hiscox
- Institute of Infection and Global Health, University of Liverpool, Liverpool L3 5RF, UK.
- National Institute of Health Research, Health Protection Research Unit in Emerging and Zoonotic Infections, Liverpool L3 5RF, UK.
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11
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Alvarez Paggi D, Esperante SA, Salgueiro M, Camporeale G, de Oliveira GAP, Prat Gay G. A conformational switch balances viral RNA accessibility and protection in a nucleocapsid ring model. Arch Biochem Biophys 2019; 671:77-86. [PMID: 31229488 DOI: 10.1016/j.abb.2019.06.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 05/30/2019] [Accepted: 06/19/2019] [Indexed: 12/22/2022]
Abstract
Virus from the Mononegavirales order share common features ranging from virion structure arrangement to mechanisms of replication and transcription. One of them is the way the nucleoprotein (N) wraps and protects the RNA genome from degradation by forming a highly ordered helical nucleocapsid. However, crystal structures from numerous Mononegavirales reveal that binding to the nucleoprotein results in occluded nucleotides that hinder base pairing necessary for transcription and replication. This hints at the existence of alternative conformations of the N protein that would impact on the protein-RNA interface, allowing for transient exposure of the nucleotides without complete RNA release. Moreover, the regulation between the alternative conformations should be finely tuned. Recombinant expression of N from the respiratory syncytial virus form regular N/RNA common among all Mononegavirales, and these constitute an ideal minimal unit for investigating the mechanisms through which these structures protect RNA so efficiently while allowing for partial accessibility during transcription and replication. Neither pH nor high ionic strength could dissociate the RNA but led to irreversible aggregation of the nucleoprotein. Low concentrations of guanidine chloride dissociated the RNA moiety but leading to irreversible aggregation of the protein moiety. On the other hand, high concentrations of urea and long incubation periods were required to remove bound RNA. Both denaturants eventually led to unfolding but converged in the formation of an RNA-free β-enriched intermediate species that remained decameric even at high denaturant concentrations. Although the N-RNA rings interact with the phosphoprotein P, the scaffold of the RNA polymerase complex, this interaction did not lead to RNA dissociation from the rings in vitro. Thus, we have uncovered complex equilibria involving changes in secondary structure of N and RNA loosening, processes that must take place in the context of RNA transcription and replication, whose detailed mechanisms and cellular and viral participants need to be established.
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Affiliation(s)
- D Alvarez Paggi
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Argentina.
| | - S A Esperante
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Argentina
| | - M Salgueiro
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Argentina
| | - G Camporeale
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Argentina
| | - G A P de Oliveira
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica Leopoldo de Meis, Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Centro Nacional de Ressonância Magnêtica Nuclear Jiri Jonas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil and Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22908-0733, USA
| | - G Prat Gay
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Argentina.
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12
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Webby MN, Sullivan MP, Yegambaram KM, Radjainia M, Keown JR, Kingston RL. A method for analyzing the composition of viral nucleoprotein complexes, produced by heterologous expression in bacteria. Virology 2018; 527:159-168. [PMID: 30529564 DOI: 10.1016/j.virol.2018.11.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 10/23/2018] [Accepted: 11/22/2018] [Indexed: 12/27/2022]
Abstract
Viral genomes are protected and organized by virally encoded packaging proteins. Heterologous production of these proteins often results in formation of particles resembling the authentic viral capsid or nucleocapsid, with cellular nucleic acids packaged in place of the viral genome. Quantifying the total protein and nucleic acid content of particle preparations is a recurrent biochemical problem. We describe a method for resolving this problem, developed when characterizing particles resembling the Menangle Virus nucleocapsid. The protein content was quantified using the biuret assay, which is largely independent of amino acid composition. Bound nucleic acids were quantified by determining the phosphorus content, using inductively coupled plasma mass spectrometry. Estimates for the amount of RNA packaged within the particles were consistent with the structurally-characterized packaging mechanism. For a bacterially-produced nucleoprotein complex, phosphorus usually provides a unique elemental marker of bound nucleic acids, hence this method of analysis should be routinely applicable.
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Affiliation(s)
- Melissa N Webby
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Matthew P Sullivan
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand
| | | | - Mazdak Radjainia
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Jeremy R Keown
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Richard L Kingston
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.
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13
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In vitro assembly of Ebola virus nucleocapsid-like complex expressed in E. coli. Protein Cell 2016; 7:888-898. [PMID: 27650953 PMCID: PMC5205660 DOI: 10.1007/s13238-016-0314-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 08/12/2016] [Indexed: 11/02/2022] Open
Abstract
Ebola virus (EBOV) harbors an RNA genome encapsidated by nucleoprotein (NP) along with other viral proteins to form a nucleocapsid complex. Previous Cryo-eletron tomography and biochemical studies have shown the helical structure of EBOV nucleocapsid at nanometer resolution and the first 450 amino-acid of NP (NPΔ451-739) alone is capable of forming a helical nucleocapsid-like complex (NLC). However, the structural basis for NP-NP interaction and the dynamic procedure of the nucleocapsid assembly is yet poorly understood. In this work, we, by using an E. coli expression system, captured a series of images of NPΔ451-739 conformers at different stages of NLC assembly by negative-stain electron microscopy, which allowed us to picture the dynamic procedure of EBOV nucleocapsid assembly. Along with further biochemical studies, we showed the assembly of NLC is salt-sensitive, and also established an indispensible role of RNA in this process. We propose the diverse modes of NLC elongation might be the key determinants shaping the plasticity of EBOV virions. Our findings provide a new model for characterizing the self-oligomerization of viral nucleoproteins and studying the dynamic assembly process of viral nucleocapsid in vitro.
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14
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Fearns R, Deval J. New antiviral approaches for respiratory syncytial virus and other mononegaviruses: Inhibiting the RNA polymerase. Antiviral Res 2016; 134:63-76. [PMID: 27575793 DOI: 10.1016/j.antiviral.2016.08.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 07/27/2016] [Accepted: 08/07/2016] [Indexed: 11/16/2022]
Abstract
Worldwide, respiratory syncytial virus (RSV) causes severe disease in infants, the elderly, and immunocompromised people. No vaccine or effective antiviral treatment is available. RSV is a member of the non-segmented, negative-strand (NNS) group of RNA viruses and relies on its RNA-dependent RNA polymerase to transcribe and replicate its genome. Because of its essential nature and unique properties, the RSV polymerase has proven to be a good target for antiviral drugs, with one compound, ALS-8176, having already achieved clinical proof-of-concept efficacy in a human challenge study. In this article, we first provide an overview of the role of the RSV polymerase in viral mRNA transcription and genome replication. We then review past and current approaches to inhibiting the RSV polymerase, including use of nucleoside analogs and non-nucleoside inhibitors. Finally, we consider polymerase inhibitors that hold promise for treating infections with other NNS RNA viruses, including measles and Ebola.
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Affiliation(s)
- Rachel Fearns
- Department of Microbiology, Boston University School of Medicine, Boston, MA, USA.
| | - Jerome Deval
- Alios BioPharma, Inc., Part of the Janssen Pharmaceutical Companies, South San Francisco, CA, USA.
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15
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Investigating the Influence of Ribavirin on Human Respiratory Syncytial Virus RNA Synthesis by Using a High-Resolution Transcriptome Sequencing Approach. J Virol 2016; 90:4876-4888. [PMID: 26656699 PMCID: PMC4859727 DOI: 10.1128/jvi.02349-15] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 11/18/2015] [Indexed: 11/20/2022] Open
Abstract
Human respiratory syncytial virus (HRSV) is a major cause of serious respiratory tract infection. Treatment options include administration of ribavirin, a purine analog, although the mechanism of its anti-HRSV activity is unknown. We used transcriptome sequencing (RNA-seq) to investigate the genome mutation frequency and viral mRNA accumulation in HRSV-infected cells that were left untreated or treated with ribavirin. In the absence of ribavirin, HRSV-specific transcripts accounted for up to one-third of total RNA reads from the infected-cell RNA population. Ribavirin treatment resulted in a >90% reduction in abundance of viral mRNA reads, while at the same time no such reduction was detected for the abundance of cellular transcripts. The presented data reveal that ribavirin significantly increases the frequency of HRSV-specific RNA mutations, suggesting a direct influence on the fidelity of the HRSV polymerase. The presented data show that transitions and transversions occur during HRSV replication and that these changes occur in hot spots along the HRSV genome. Examination of nucleotide substitution rates in the viral genome indicated an increase in the frequency of transition but not transversion mutations in the presence of ribavirin. In addition, our data indicate that in the continuous cell types used and at the time points analyzed, the abundances of some HRSV mRNAs do not reflect the order in which the mRNAs are transcribed. IMPORTANCE Human respiratory syncytial virus (HRSV) is a major pediatric pathogen. Ribavirin can be used in children who are extremely ill to reduce the amount of virus and to lower the burden of disease. Ribavirin is used as an experimental therapy with other viruses. The mechanism of action of ribavirin against HRSV is not well understood, although it is thought to increase the mutation rate of the viral polymerase during replication. To investigate this hypothesis, we used a high-resolution approach that allowed us to determine the genetic sequence of the virus to a great depth of coverage. We found that ribavirin did not cause a detectable change in the relative amounts of viral mRNA transcripts. However, we found that ribavirin treatment did indeed cause an increase in the number of mutations, which was associated with a decrease in virus production.
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16
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Olal D, Daumke O. Structure of the Hantavirus Nucleoprotein Provides Insights into the Mechanism of RNA Encapsidation. Cell Rep 2016; 14:2092-2099. [PMID: 26923588 DOI: 10.1016/j.celrep.2016.02.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 12/07/2015] [Accepted: 01/25/2016] [Indexed: 11/19/2022] Open
Abstract
Hantaviruses are etiological agents of life-threatening hemorrhagic fever with renal syndrome and hantavirus cardiopulmonary syndrome. The nucleoprotein (N) of hantavirus is essential for viral transcription and replication, thus representing an attractive target for therapeutic intervention. We have determined the crystal structure of hantavirus N to 3.2 Å resolution. The structure reveals a two-lobed, mostly α-helical structure that is distantly related to that of orthobunyavirus Ns. A basic RNA binding pocket is located at the intersection between the two lobes. We provide evidence that oligomerization is mediated by amino- and C-terminal arms that bind to the adjacent monomers. Based on these findings, we suggest a model for the oligomeric ribonucleoprotein (RNP) complex. Our structure provides mechanistic insights into RNA encapsidation in the genus Hantavirus and constitutes a template for drug discovery efforts aimed at combating hantavirus infections.
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Affiliation(s)
- Daniel Olal
- Crystallography, Max Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13125 Berlin, Germany.
| | - Oliver Daumke
- Crystallography, Max Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13125 Berlin, Germany; Biochemie, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany.
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17
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Oliveira AP, Simabuco FM, Tamura RE, Guerrero MC, Ribeiro PGG, Libermann TA, Zerbini LF, Ventura AM. Human respiratory syncytial virus N, P and M protein interactions in HEK-293T cells. Virus Res 2013; 177:108-12. [PMID: 23892143 DOI: 10.1016/j.virusres.2013.07.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 07/06/2013] [Accepted: 07/11/2013] [Indexed: 01/09/2023]
Abstract
Characterization of Human Respiratory Syncytial Virus (HRSV) protein interactions with host cell components is crucial to devise antiviral strategies. Viral nucleoprotein, phosphoprotein and matrix protein genes were optimized for human codon usage and cloned into expression vectors. HEK-293T cells were transfected with these vectors, viral proteins were immunoprecipitated, and co-immunoprecipitated cellular proteins were identified through mass spectrometry. Cell proteins identified with higher confidence scores were probed in the immunoprecipitation using specific antibodies. The results indicate that nucleoprotein interacts with arginine methyl-transferase, methylosome protein and Hsp70. Phosphoprotein interacts with Hsp70 and tropomysin, and matrix with tropomysin and nucleophosmin. Additionally, we performed immunoprecipitation of these cellular proteins in cells infected with HRSV, followed by detection of co-immunoprecipitated viral proteins. The results indicate that these interactions also occur in the context of viral infection, and their potential contribution for a HRSV replication model is discussed.
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Affiliation(s)
- Andressa P Oliveira
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
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18
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Noton SL, Deflubé LR, Tremaglio CZ, Fearns R. The respiratory syncytial virus polymerase has multiple RNA synthesis activities at the promoter. PLoS Pathog 2012; 8:e1002980. [PMID: 23093940 PMCID: PMC3475672 DOI: 10.1371/journal.ppat.1002980] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 09/06/2012] [Indexed: 12/21/2022] Open
Abstract
Respiratory syncytial virus (RSV) is an RNA virus in the Family Paramyxoviridae. Here, the activities performed by the RSV polymerase when it encounters the viral antigenomic promoter were examined. RSV RNA synthesis was reconstituted in vitro using recombinant, isolated polymerase and an RNA oligonucleotide template representing nucleotides 1–25 of the trailer complement (TrC) promoter. The RSV polymerase was found to have two RNA synthesis activities, initiating RNA synthesis from the +3 site on the promoter, and adding a specific sequence of nucleotides to the 3′ end of the TrC RNA using a back-priming mechanism. Examination of viral RNA isolated from RSV infected cells identified RNAs initiated at the +3 site on the TrC promoter, in addition to the expected +1 site, and showed that a significant proportion of antigenome RNAs contained specific nucleotide additions at the 3′ end, demonstrating that the observations made in vitro reflected events that occur during RSV infection. Analysis of the impact of the 3′ terminal extension on promoter activity indicated that it can inhibit RNA synthesis initiation. These findings indicate that RSV polymerase-promoter interactions are more complex than previously thought and suggest that there might be sophisticated mechanisms for regulating promoter activity during infection. Respiratory syncytial virus (RSV) is a major pathogen of infants with the potential to cause severe respiratory disease. RSV has an RNA genome and one approach to developing a drug against this virus is to gain a greater understanding of the mechanisms used by the viral polymerase to generate new RNA. In this study we developed a novel assay for examining how the RSV polymerase interacts with a specific promoter sequence at the end of an RNA template, and performed analysis of RSV RNA produced in infected cells to confirm the findings. Our experiments showed that the behavior of the polymerase on the promoter was surprisingly complex. We found that not only could the polymerase initiate synthesis of progeny genome RNA from an initiation site at the end of the template, but it could also generate another small RNA from a second initiation site. In addition, we showed that the polymerase could add additional RNA sequence to the template promoter, which affected its ability to initiate RNA synthesis. These findings extend our understanding of the functions of the promoter, and suggest a mechanism by which RNA synthesis from the promoter is regulated.
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Affiliation(s)
- Sarah L. Noton
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Laure R. Deflubé
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Chadene Z. Tremaglio
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Rachel Fearns
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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19
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Structure of Crimean-Congo hemorrhagic fever virus nucleoprotein: superhelical homo-oligomers and the role of caspase-3 cleavage. J Virol 2012; 86:12294-303. [PMID: 22951837 DOI: 10.1128/jvi.01627-12] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Crimean-Congo hemorrhagic fever, a severe hemorrhagic disease found throughout Africa, Europe, and Asia, is caused by the tick-borne Crimean-Congo hemorrhagic fever virus (CCHFV). CCHFV is a negative-sense single-stranded RNA (ssRNA) virus belonging to the Nairovirus genus of the Bunyaviridae family. Its genome of three single-stranded RNA segments is encapsidated by the nucleocapsid protein (CCHFV N) to form the ribonucleoprotein complex. This ribonucleoprotein complex is required during replication and transcription of the viral genomic RNA. Here, we present the crystal structures of the CCHFV N in two distinct forms, an oligomeric form comprised of double antiparallel superhelices and a monomeric form. The head-to-tail interaction of the stalk region of one CCHFV N subunit with the base of the globular body of the adjacent subunit stabilizes the helical organization of the oligomeric form of CCHFV N. It also masks the conserved caspase-3 cleavage site present at the tip of the stalk region from host cell caspase-3 interaction and cleavage. By incubation with primer-length ssRNAs, we also obtained the crystal structure of CCHFV N in its monomeric form, which is similar to a recently published structure. The conformational change of CCHFV N upon deoligomerization results in the exposure of the caspase-3 cleavage site and subjects CCHFV N to caspase-3 cleavage. Mutations of this cleavage site inhibit cleavage by caspase-3 and result in enhanced viral polymerase activity. Thus, cleavage of CCHFV N by host cell caspase-3 appears to be crucial for controlling viral RNA synthesis and represents an important host defense mechanism against CCHFV infection.
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20
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Crystal structure of the Lassa virus nucleoprotein-RNA complex reveals a gating mechanism for RNA binding. Proc Natl Acad Sci U S A 2011; 108:19365-70. [PMID: 22084115 DOI: 10.1073/pnas.1108515108] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Arenaviruses cause disease in industrialized and developing nations alike. Among them, the hemorrhagic fever virus Lassa is responsible for ~300,000-500,000 infections/y in Western Africa. The arenavirus nucleoprotein (NP) forms the protein scaffold of the genomic ribonucleoprotein complexes and is critical for transcription and replication of the viral genome. Here, we present crystal structures of the RNA-binding domain of Lassa virus NP in complex with ssRNA. This structure shows, in contrast to the predicted model, that RNA binds in a deep, basic crevice located entirely within the N-terminal domain. Furthermore, the NP-ssRNA structures presented here, combined with hydrogen-deuterium exchange/MS and functional studies, suggest a gating mechanism by which NP opens to accept RNA. Directed mutagenesis and functional studies provide a unique look into how the arenavirus NPs bind to and protect the viral genome and also suggest the likely assembly by which viral ribonucleoprotein complexes are organized.
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21
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Harris JR, Soliakov A, Lewis RJ, Depoix F, Watkinson A, Lakey JH. Alhydrogel® adjuvant, ultrasonic dispersion and protein binding: a TEM and analytical study. Micron 2011; 43:192-200. [PMID: 21831642 DOI: 10.1016/j.micron.2011.07.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 07/10/2011] [Accepted: 07/11/2011] [Indexed: 01/25/2023]
Abstract
Aluminium-based vaccine adjuvants have been in use since the 1920s. Aluminium hydroxide (alum) that is the chemical basis of Alhydrogel, a widely used adjuvant, is a colloid that binds proteins to the particular surface for efficient presentation to the immune system during the vaccination process. Using conventional TEM and cryo-TEM we have shown that Alhydrogel can be finely dispersed by ultrasonication of the aqueous suspension. Clusters of ultrasonicated aluminium hydroxide micro-fibre crystals have been produced (∼ 10-100 nm), that are significantly smaller than those present the untreated Alhydrogel (∼ 2-12 μm). However, even prolonged ultrasonication did not produce a homogenous suspension of single aluminium hydroxide micro-fibres. The TEM images of unstained and negatively stained air-dried Alhydrogel are very similar to those obtained by cryo-electron microscopy. Visualization of protein on the surface of the finely dispersed Alhydrogel by TEM is facilitated by prior ultrasonication. Several examples are given, including some of medical relevance, using proteins of widely ranging molecular mass and oligomerization state. Even with the smaller mass proteins, their presence on the Alhydrogel surface can be readily defined by TEM. It has been found that low quantities of protein tend to cross-link and aggregate the small Alhydogel clusters, in a more pronounced manner than high protein concentrations. This indicates that complete saturation of the available Alhydrogel surface with protein may be achieved, with minimal cross-linkage, and future exploitation of this treatment of Alhydrogel is likely to be of immediate value for more efficient vaccine production.
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Affiliation(s)
- J Robin Harris
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
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22
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Hanley LL, McGivern DR, Teng MN, Djang R, Collins PL, Fearns R. Roles of the respiratory syncytial virus trailer region: effects of mutations on genome production and stress granule formation. Virology 2010; 406:241-52. [PMID: 20701943 DOI: 10.1016/j.virol.2010.07.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 05/03/2010] [Accepted: 07/02/2010] [Indexed: 12/16/2022]
Abstract
The 5' extragenic trailer region of respiratory syncytial virus (RSV) is known to be necessary for genome replication, but is more than three times the length of the 3' leader replication promoter, raising the possibility that trailer might play an additional role in viral replication. To examine this, mutant recombinant viruses were constructed in which the trailer region was truncated or substituted with leader-complement sequence. This analysis showed that the complete trailer increased promoter activity, facilitating genome production and viral multiplication. In addition, trailer-containing viruses did not induce stress granules, whereas the leader-complement virus mutant did, resulting in poor multi-cycle viral growth. These data demonstrate that although the RSV trailer does not contain a unique essential sequence, it augments virus growth by enabling optimal genome production. In addition, a sequence at the 5' terminal end of the trailer region allows RSV to subvert stress granule formation.
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Affiliation(s)
- Laura L Hanley
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, USA
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23
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Sarkar A, Chattopadhyay S, Cox R, Luo M, Banerjee AK. Structural and functional properties of the vesicular stomatitis virus nucleoprotein-RNA complex as revealed by proteolytic digestion. Virology 2010; 401:61-9. [PMID: 20206958 PMCID: PMC2853252 DOI: 10.1016/j.virol.2010.02.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Revised: 01/05/2010] [Accepted: 02/09/2010] [Indexed: 12/31/2022]
Abstract
To gain insight into the structural and functional properties of the vesicular stomatitis virus nucleocapsid-RNA complex (vN-RNA), we analyzed it by treatment with proteolytic enzymes. Chymotrypsin treatment to the vN-RNA results in complete digestion of the C-terminal 86 amino acids of the N protein. The residual chymotrypsin resistant vN-RNA complex (vDeltaN-RNA) carrying N-terminal 336 amino acids of the N protein (DeltaN) was inactive in transcription. The DeltaN protein retained its capability to protect the genomic RNA from nuclease digestion but failed to interact to the P protein. Interestingly, addition of excess amount of P protein rendered the vN-RNA complex resistant to the chymotrypsin digestion. Finally, our data revealed that the recombinant N-RNA complex purified from bacteria (bN-RNA) is resistant to chymotrypsin digestion, suggesting that the C-terminal unstructured domain (C-loop) remains inaccessible to protease digestion. Detailed comparative analyses of the vN-RNA and vDeltaN-RNA are discussed.
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Affiliation(s)
- Anindya Sarkar
- Department of Molecular Genetics, Section of Virology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
| | - Santanu Chattopadhyay
- Department of Molecular Genetics, Section of Virology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
| | - Robert Cox
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294 USA
| | - Ming Luo
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294 USA
| | - Amiya K. Banerjee
- Department of Molecular Genetics, Section of Virology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
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24
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Hock M, Kraus I, Schoehn G, Jamin M, Andrei-Selmer C, Garten W, Weissenhorn W. RNA induced polymerization of the Borna disease virus nucleoprotein. Virology 2010; 397:64-72. [DOI: 10.1016/j.virol.2009.11.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Revised: 10/29/2009] [Accepted: 11/10/2009] [Indexed: 10/20/2022]
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25
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Tawar RG, Duquerroy S, Vonrhein C, Varela PF, Damier-Piolle L, Castagné N, MacLellan K, Bedouelle H, Bricogne G, Bhella D, Eléouët JF, Rey FA. Crystal structure of a nucleocapsid-like nucleoprotein-RNA complex of respiratory syncytial virus. Science 2009; 326:1279-83. [PMID: 19965480 DOI: 10.1126/science.1177634] [Citation(s) in RCA: 260] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The respiratory syncytial virus (RSV) is an important human pathogen, yet neither a vaccine nor effective therapies are available to treat infection. To help elucidate the replication mechanism of this RNA virus, we determined the three-dimensional (3D) crystal structure at 3.3 A resolution of a decameric, annular ribonucleoprotein complex of the RSV nucleoprotein (N) bound to RNA. This complex mimics one turn of the viral helical nucleocapsid complex, which serves as template for viral RNA synthesis. The RNA wraps around the protein ring, with seven nucleotides contacting each N subunit, alternating rows of four and three stacked bases that are exposed and buried within a protein groove, respectively. Combined with electron microscopy data, this structure provides a detailed model for the RSV nucleocapsid, in which the bases are accessible for readout by the viral polymerase. Furthermore, the nucleoprotein structure highlights possible key sites for drug targeting.
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Affiliation(s)
- Rajiv G Tawar
- Institut Pasteur, Unité de Virologie Structurale, Département de Virologie and CNRS Unité de Recherche Associée (URA) 3015, 25 Rue du Dr Roux, 75724 Paris Cedex 15, France
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26
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Abstract
The nucleocapsid protein (NP) of mumps virus (MuV), a paramyxovirus, was coexpressed with the phosphoprotein (P) in Escherichia coli. The NP and P proteins form a soluble complex containing RNA. Under a transmission electron microscope, the NP-RNA complex appears as a nucleocapsidlike ring that has a diameter of approximately 20 nm with 13 subunits. There is a piece of single-stranded RNA with a length of 78 nucleotides in the NP-RNA ring. Shorter RNA pieces are also visible. The MuV NP protein may provide weaker protection of the RNA than the NP protein of some other negative-strand RNA viruses, reflecting the degree of NP protein association.
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27
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Ong ST, Yusoff K, Kho CL, Abdullah JO, Tan WS. Mutagenesis of the nucleocapsid protein of Nipah virus involved in capsid assembly. J Gen Virol 2009; 90:392-397. [PMID: 19141448 DOI: 10.1099/vir.0.005710-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The nucleocapsid protein of Nipah virus produced in Escherichia coli assembled into herringbone-like particles. The amino- and carboxy-termini of the N protein were shortened progressively to define the minimum contiguous sequence involved in capsid assembly. The first 29 aa residues of the N protein are dispensable for capsid formation. The 128 carboxy-terminal residues do not play a role in the assembly of the herringbone-like particles. A region with amino acid residues 30-32 plays a crucial role in the formation of the capsid particle. Deletion of any of the four conserved hydrophobic regions in the N protein impaired capsid formation. Replacement of the central conserved regions with the respective sequences from the Newcastle disease virus restored capsid formation.
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Affiliation(s)
- Swee Tin Ong
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Khatijah Yusoff
- Institute of Bioscience, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.,Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Chiew Ling Kho
- Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, UTAR Complex, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur, Malaysia
| | - Janna Ong Abdullah
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Wen Siang Tan
- Institute of Bioscience, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.,Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
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28
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Infectious Bursal disease virus: ribonucleoprotein complexes of a double-stranded RNA virus. J Mol Biol 2008; 386:891-901. [PMID: 19063900 PMCID: PMC7173181 DOI: 10.1016/j.jmb.2008.11.029] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 11/17/2008] [Accepted: 11/18/2008] [Indexed: 11/22/2022]
Abstract
Genome-binding proteins with scaffolding and/or regulatory functions are common in living organisms and include histones in eukaryotic cells, histone-like proteins in some double-stranded DNA (dsDNA) viruses, and the nucleocapsid proteins of single-stranded RNA viruses. dsRNA viruses nevertheless lack these ribonucleoprotein (RNP) complexes and are characterized by sharing an icosahedral T=2 core involved in the metabolism and insulation of the dsRNA genome. The birnaviruses, with a bipartite dsRNA genome, constitute a well-established exception and have a single-shelled T=13 capsid only. Moreover, as in many negative single-stranded RNA viruses, the genomic dsRNA is bound to a nucleocapsid protein (VP3) and the RNA-dependent RNA polymerase (VPg). We used electron microscopy and functional analysis to characterize these RNP complexes of infectious bursal disease virus, the best characterized member of the Birnaviridae family. Mild disruption of viral particles revealed that VP3, the most abundant core protein, present at approximately 450 copies per virion, is found in filamentous material tightly associated with the dsRNA. We developed a method to purify RNP and VPg-dsRNA complexes. Analysis of these complexes showed that they are linear molecules containing a constant amount of protein. Sensitivity assays to nucleases indicated that VP3 renders the genomic dsRNA less accessible for RNase III without introducing genome compaction. Additionally, we found that these RNP complexes are functionally competent for RNA synthesis in a capsid-independent manner, in contrast to most dsRNA viruses.
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29
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El Omari K, Scott K, Dhaliwal B, Ren J, Abrescia NGA, Budworth J, Lockyer M, Powell KL, Hawkins AR, Stammers DK. Crystallization and preliminary X-ray analysis of the human respiratory syncytial virus nucleocapsid protein. Acta Crystallogr Sect F Struct Biol Cryst Commun 2008; 64:1019-23. [PMID: 18997331 PMCID: PMC2581706 DOI: 10.1107/s1744309108031059] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Accepted: 09/25/2008] [Indexed: 11/10/2022]
Abstract
Human respiratory syncytial virus (HRSV) has a nonsegmented negative-stranded RNA genome which is encapsidated by the HRSV nucleocapsid protein (HRSVN) that is essential for viral replication. HRSV is a common cause of respiratory infection in infants, yet no effective antiviral drugs to combat it are available. Recent data from an experimental anti-HRSV compound, RSV-604, indicate that HRSVN could be the target site for drug action. Here, the expression, purification and preliminary data collection of decameric HRSVN as well as monomeric N-terminally truncated HRSVN mutants are reported. Two different crystal forms of full-length selenomethionine-labelled HRSVN were obtained that diffracted to 3.6 and approximately 5 A resolution and belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 133.6, b = 149.9, c = 255.1 A, and space group P2(1), with unit-cell parameters a = 175.1, b = 162.6, c = 242.8 A, beta = 90.1 degrees , respectively. For unlabelled HRSVN, only crystals belonging to space group P2(1) were obtained that diffracted to 3.6 A. A self-rotation function using data from the orthorhombic crystal form confirmed the presence of tenfold noncrystallographic symmetry, which is in agreement with a reported electron-microscopic reconstruction of HRSVN. Monomeric HRSVN generated by N-terminal truncation was designed to assist in structure determination by reducing the size of the asymmetric unit. Whilst such HRSVN mutants were monomeric in solution and crystallized in a different space group, the size of the asymmetric unit was not reduced.
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Affiliation(s)
- K. El Omari
- Division of Structural Biology, The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, England
| | - K. Scott
- Division of Structural Biology, The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, England
| | - B. Dhaliwal
- Division of Structural Biology, The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, England
| | - J. Ren
- Division of Structural Biology, The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, England
| | - N. G. A. Abrescia
- Division of Structural Biology, The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, England
| | - J. Budworth
- Arrow Therapeutics Ltd, Britannia House, Trinity Street, Borough, London SE1 1DB, England
| | - M. Lockyer
- Arrow Therapeutics Ltd, Britannia House, Trinity Street, Borough, London SE1 1DB, England
| | - K. L. Powell
- Arrow Therapeutics Ltd, Britannia House, Trinity Street, Borough, London SE1 1DB, England
| | - A. R. Hawkins
- Institute of Cell and Molecular Biosciences, Catherine Cookson Building, Medical School, Framlington Place, Newcastle University, Newcastle-upon-Tyne NE2 4HH, England
| | - D. K. Stammers
- Division of Structural Biology, The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, England
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