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Konevtsova OV, Chalin DV, Rochal SB. Theory of density waves and organization of proteins in icosahedral virus capsids. Phys Chem Chem Phys 2023; 26:569-580. [PMID: 38086647 DOI: 10.1039/d3cp05384a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Understanding the physical principles underlying the structural organization of the proteinaceous viral shells is of major importance to advance antiviral strategies. Here, we develop a phenomenological thermodynamic theory, which considers structures of small and middle-size icosahedral viral shells as a result of condensation of a minimum number of protein density waves on a spherical surface. Each of these irreducible critical waves has icosahedral symmetry and can be expressed as a specific series of the spherical harmonics Ylm with the same wave number l. As we demonstrate, in small viral shells self-assembled from individual proteins, the maxima of one critical density wave determine the positions of proteins, while the spatial derivatives of the second one control the protein orientations on the shell surface. In contrast to the small shells, the middle-size ones are always formed from pentamers and hexamers (referred to as capsomers). Considering all such structures deposited in the Protein Data Bank, we unexpectedly found that the positions of capsomeres in these shells correspond to the maxima of interference patterns produced by no more than two critical waves with close wave numbers. This fact allows us to explain the observed limit size of the icosahedral shells assembled from pentamers and hexamers. We also construct nonequilibrium thermodynamic potentials describing the protein crystallization and discuss the reasons behind the specific handedness of the viral shells.
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Affiliation(s)
- Olga V Konevtsova
- Faculty of Physics, Southern Federal University, 5 Zorge str., 344090 Rostov-on-Don, Russia.
| | - Dmitrii V Chalin
- Faculty of Physics, Southern Federal University, 5 Zorge str., 344090 Rostov-on-Don, Russia.
| | - Sergei B Rochal
- Faculty of Physics, Southern Federal University, 5 Zorge str., 344090 Rostov-on-Don, Russia.
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2
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Heymann JB. Structural Studies of Bacteriophage Φ6 and Its Transformations during Its Life Cycle. Viruses 2023; 15:2404. [PMID: 38140645 PMCID: PMC10747372 DOI: 10.3390/v15122404] [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: 10/24/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 12/24/2023] Open
Abstract
From the first isolation of the cystovirus bacteriophage Φ6 from Pseudomonas syringae 50 years ago, we have progressed to a better understanding of the structure and transformations of many parts of the virion. The three-layered virion, encapsulating the tripartite double-stranded RNA (dsRNA) genome, breaches the cell envelope upon infection, generates its own transcripts, and coopts the bacterial machinery to produce its proteins. The generation of a new virion starts with a procapsid with a contracted shape, followed by the packaging of single-stranded RNA segments with concurrent expansion of the capsid, and finally replication to reconstitute the dsRNA genome. The outer two layers are then added, and the fully formed virion released by cell lysis. Most of the procapsid structure, composed of the proteins P1, P2, P4, and P7 is now known, as well as its transformations to the mature, packaged nucleocapsid. The outer two layers are less well-studied. One additional study investigated the binding of the host protein YajQ to the infecting nucleocapsid, where it enhances the transcription of the large RNA segment that codes for the capsid proteins. Finally, I relate the structural aspects of bacteriophage Φ6 to those of other dsRNA viruses, noting the similarities and differences.
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Affiliation(s)
- J. Bernard Heymann
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, 50 South Dr., Bethesda, MD 20892, USA; ; Tel.: +1-301-846-6924
- National Cryo-EM Program, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21701, USA
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3
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Rochal SB, Konevtsova OV, Golushko IY, Podgornik R. Close packings of identical proteins in small spherical capsids and similar proteinaceous shells. SOFT MATTER 2023; 19:8649-8658. [PMID: 37921635 DOI: 10.1039/d3sm01106b] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2023]
Abstract
Understanding the principles governing protein arrangement in viral capsids and structurally similar protein shells can enable the development of new antiviral strategies and the design of artificial protein cages for various applications. We study these principles within the context of the close packing problem, by analyzing dozens of small spherical shells assembled from a single type of protein. First, we use icosahedral spherical close packings containing 60T identical disks, where T ≤ 4, to rationalize the protein arrangement in twenty real icosahedral shells both satisfying and violating the paradigmatic Caspar-Klug model. We uncover a striking correspondence between the protein mass centers in the considered shells and the centers of disks in the close packings. To generalize the packing model, we consider proteins with a weak shape anisotropy and propose an interaction energy, minimization of which allows us to obtain spherical dense packings of slightly anisotropic structural units. In the case of strong anisotropy, we model the proteins as sequences of overlapping discs of different sizes, with minimum energy configuration not only resulting in packings, accurately reproducing locations and orientations of individual proteins, but also revealing that icosahedral packings that display the handedness of real capsids are energetically more favorable. Finally, by introducing effective disc charges, we rationalize the formation of inter-protein bonds in protein shells.
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Affiliation(s)
- Sergei B Rochal
- Physics Faculty, Southern Federal University, Rostov-on-Don, Russia.
| | - Olga V Konevtsova
- Physics Faculty, Southern Federal University, Rostov-on-Don, Russia.
| | - Ivan Yu Golushko
- Physics Faculty, Southern Federal University, Rostov-on-Don, Russia.
| | - Rudolf Podgornik
- School of Physical Sciences and Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
- CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Wenzhou Institute of the University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325000, China
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Mäntynen S, Salomaa MM, Poranen MM. Diversity and Current Classification of dsRNA Bacteriophages. Viruses 2023; 15:2154. [PMID: 38005832 PMCID: PMC10674327 DOI: 10.3390/v15112154] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/11/2023] [Accepted: 10/22/2023] [Indexed: 11/26/2023] Open
Abstract
Half a century has passed since the discovery of Pseudomonas phage phi6, the first enveloped dsRNA bacteriophage to be isolated. It remained the sole known dsRNA phage for a quarter of a century and the only recognised member of the Cystoviridae family until the year 2018. After the initial discovery of phi6, additional dsRNA phages have been isolated from globally distant locations and identified in metatranscriptomic datasets, suggesting that this virus type is more ubiquitous in nature than previously acknowledged. Most identified dsRNA phages infect Pseudomonas strains and utilise either pilus or lipopolysaccharide components of the host as the primary receptor. In addition to the receptor-mediated strictly lytic lifestyle, an alternative persistent infection strategy has been described for some dsRNA phages. To date, complete genome sequences of fourteen dsRNA phage isolates are available. Despite the high sequence diversity, similar sets of genes can typically be found in the genomes of dsRNA phages, suggesting shared evolutionary trajectories. This review provides a brief overview of the recognised members of the Cystoviridae virus family and related dsRNA phage isolates, outlines the current classification of dsRNA phages, and discusses their relationships with eukaryotic RNA viruses.
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Affiliation(s)
- Sari Mäntynen
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014 Helsinki, Finland; (M.M.S.); (M.M.P.)
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Gottlieb P, Alimova A. Discovery and Classification of the φ6 Bacteriophage: An Historical Review. Viruses 2023; 15:1308. [PMID: 37376608 DOI: 10.3390/v15061308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/30/2023] [Accepted: 05/28/2023] [Indexed: 06/29/2023] Open
Abstract
The year 2023 marks the fiftieth anniversary of the discovery of the bacteriophage φ6. The review provides a look back on the initial discovery and classification of the lipid-containing and segmented double-stranded RNA (dsRNA) genome-containing bacteriophage-the first identified cystovirus. The historical discussion describes, for the most part, the first 10 years of the research employing contemporary mutation techniques, biochemical, and structural analysis to describe the basic outline of the virus replication mechanisms and structure. The physical nature of φ6 was initially controversial as it was the first bacteriophage found that contained segmented dsRNA, resulting in a series of early publications that defined the unusual genomic quality. The technology and methods utilized in the initial research (crude by current standards) meant that the first studies were quite time-consuming, hence the lengthy period covered by this review. Yet when the data were accepted, the relationship to the reoviruses was apparent, launching great interest in cystoviruses, research that continues to this day.
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Affiliation(s)
- Paul Gottlieb
- Department of Molecular, Cellular and Biomedical Sciences, The City University of New York School of Medicine, New York, NY 10031, USA
| | - Aleksandra Alimova
- Department of Molecular, Cellular and Biomedical Sciences, The City University of New York School of Medicine, New York, NY 10031, USA
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Gottlieb P, Alimova A. Heterologous RNA Recombination in the Cystoviruses φ6 and φ8: A Mechanism of Viral Variation and Genome Repair. Viruses 2022; 14:v14112589. [PMID: 36423198 PMCID: PMC9697746 DOI: 10.3390/v14112589] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/15/2022] [Accepted: 11/18/2022] [Indexed: 11/23/2022] Open
Abstract
Recombination and mutation of viral genomes represent major mechanisms for viral evolution and, in many cases, moderate pathogenicity. Segmented genome viruses frequently undergo reassortment of the genome via multiple infection of host organisms, with influenza and reoviruses being well-known examples. Specifically, major genomic shifts mediated by reassortment are responsible for radical changes in the influenza antigenic determinants that can result in pandemics requiring rapid preventative responses by vaccine modifications. In contrast, smaller mutational changes brought about by the error-prone viral RNA polymerases that, for the most part, lack a replication base mispairing editing function produce small mutational changes in the RNA genome during replication. Referring again to the influenza example, the accumulated mutations-known as drift-require yearly vaccine updating and rapid worldwide distribution of each new formulation. Coronaviruses with a large positive-sense RNA genome have long been known to undergo intramolecular recombination likely mediated by copy choice of the RNA template by the viral RNA polymerase in addition to the polymerase-based mutations. The current SARS-CoV-2 origin debate underscores the importance of understanding the plasticity of viral genomes, particularly the mechanisms responsible for intramolecular recombination. This review describes the use of the cystovirus bacteriophage as an experimental model for recombination studies in a controlled manner, resulting in the development of a model for intramolecular RNA genome alterations. The review relates the sequence of experimental studies from the laboratory of Leonard Mindich, PhD at the Public Health Research Institute-then in New York City-and covers a period of approximately 12 years. Hence, this is a historical scientific review of research that has the greatest relevance to current studies of emerging RNA virus pathogens.
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Gottlieb P, Alimova A. RNA Packaging in the Cystovirus Bacteriophages: Dynamic Interactions during Capsid Maturation. Int J Mol Sci 2022; 23:ijms23052677. [PMID: 35269819 PMCID: PMC8910881 DOI: 10.3390/ijms23052677] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 02/16/2022] [Accepted: 02/23/2022] [Indexed: 12/10/2022] Open
Abstract
The bacteriophage family Cystoviridae consists of a single genus, Cystovirus, that is lipid-containing with three double-stranded RNA (ds-RNA) genome segments. With regard to the segmented dsRNA genome, they resemble the family Reoviridae. Therefore, the Cystoviruses have long served as a simple model for reovirus assembly. This review focuses on important developments in the study of the RNA packaging and replication mechanisms, emphasizing the structural conformations and dynamic changes during maturation of the five proteins required for viral RNA synthesis, P1, P2, P4, P7, and P8. Together these proteins constitute the procapsid/polymerase complex (PC) and nucleocapsid (NC) of the Cystoviruses. During viral assembly and RNA packaging, the five proteins must function in a coordinated fashion as the PC and NC undergo expansion with significant position translation. The review emphasizes this facet of the viral assembly process and speculates on areas suggestive of additional research efforts.
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Cryo-electron Microscopy Structure, Assembly, and Mechanics Show Morphogenesis and Evolution of Human Picobirnavirus. J Virol 2020; 94:JVI.01542-20. [PMID: 32938763 DOI: 10.1128/jvi.01542-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 09/08/2020] [Indexed: 12/17/2022] Open
Abstract
Despite their diversity, most double-stranded-RNA (dsRNA) viruses share a specialized T=1 capsid built from dimers of a single protein that provides a platform for genome transcription and replication. This ubiquitous capsid remains structurally undisturbed throughout the viral cycle, isolating the genome to avoid triggering host defense mechanisms. Human picobirnavirus (hPBV) is a dsRNA virus frequently associated with gastroenteritis, although its pathogenicity is yet undefined. Here, we report the cryo-electron microscopy (cryo-EM) structure of hPBV at 2.6-Å resolution. The capsid protein (CP) is arranged in a single-shelled, ∼380-Å-diameter T=1 capsid with a rough outer surface similar to that of dsRNA mycoviruses. The hPBV capsid is built of 60 quasisymmetric CP dimers (A and B) stabilized by domain swapping, and only the CP-A N-terminal basic region interacts with the packaged nucleic acids. hPBV CP has an α-helical domain with a fold similar to that of fungal partitivirus CP, with many domain insertions in its C-terminal half. In contrast to dsRNA mycoviruses, hPBV has an extracellular life cycle phase like complex reoviruses, which indicates that its own CP probably participates in cell entry. Using an in vitro reversible assembly/disassembly system of hPBV, we isolated tetramers as possible assembly intermediates. We used atomic force microscopy to characterize the biophysical properties of hPBV capsids with different cargos (host nucleic acids or proteins) and found that the CP N-terminal segment not only is involved in nucleic acid interaction/packaging but also modulates the mechanical behavior of the capsid in conjunction with the cargo.IMPORTANCE Despite intensive study, human virus sampling is still sparse, especially for viruses that cause mild or asymptomatic disease. Human picobirnavirus (hPBV) is a double-stranded-RNA virus, broadly dispersed in the human population, but its pathogenicity is uncertain. Here, we report the hPBV structure derived from cryo-electron microscopy (cryo-EM) and reconstruction methods using three capsid protein variants (of different lengths and N-terminal amino acid compositions) that assemble as virus-like particles with distinct properties. The hPBV near-atomic structure reveals a quasisymmetric dimer as the structural subunit and tetramers as possible assembly intermediates that coassemble with nucleic acids. Our structural studies and atomic force microscopy analyses indicate that hPBV capsids are potentially excellent nanocages for gene therapy and targeted drug delivery in humans.
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9
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Konevtsova OV, Roshal DS, Podgornik R, Rochal SB. Irreversible and reversible morphological changes in the φ6 capsid and similar viral shells: symmetry and micromechanics. SOFT MATTER 2020; 16:9383-9392. [PMID: 32945317 DOI: 10.1039/d0sm01338b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Understanding the physicochemical processes occurring in viruses during their maturation is of fundamental importance since only mature viruses can infect host cells. Here we consider the irreversible and reversible morphological changes that occur with the dodecahedral φ6 procapsid during the sequential packaging of 3 RNA segments forming the viral genome. It is shown that the dodecahedral shape of all the four observed capsid states is perfectly reproduced by a sphere radially deformed by only two irreducible spherical harmonics with icosahedral symmetry and wave numbers l = 6 and l = 10. The rotation of proteins around the 3-fold axes at the Procapsid → Intermediate 1 irreversible transformation is in fact also well described with the shear field containing only two irreducible harmonics with the same two wave numbers. The high stability of the Intermediate 1 state is discussed and the shapes of the Intermediate 2 state and Capsid (reversibly transforming back to the Intermediate 1 state) are shown to be mainly due to the isotropic pressure that the encapsidated RNA segments exert on the shell walls. The hidden symmetry of the capsid and the physicochemical features of the in vitro genome extraction from the viral shell are also elucidated.
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Affiliation(s)
- Olga V Konevtsova
- Physics Faculty, Southern Federal University, Rostov-on-Don, Russia.
| | - Daria S Roshal
- Physics Faculty, Southern Federal University, Rostov-on-Don, Russia.
| | - Rudolf Podgornik
- Department of Theoretical Physics, JoŽef Stefan Institute, SI-1000 Ljubljana, Slovenia and Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia and School of Physical Sciences and Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Sergei B Rochal
- Physics Faculty, Southern Federal University, Rostov-on-Don, Russia.
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10
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Mata CP, Rodríguez JM, Suzuki N, Castón JR. Structure and assembly of double-stranded RNA mycoviruses. Adv Virus Res 2020; 108:213-247. [PMID: 33837717 DOI: 10.1016/bs.aivir.2020.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mycoviruses are a diverse group that includes ssRNA, dsRNA, and ssDNA viruses, with or without a protein capsid, as well as with a complex envelope. Most mycoviruses are transmitted by cytoplasmic interchange and are thought to lack an extracellular phase in their infection cycle. Structural analysis has focused on dsRNA mycoviruses, which usually package their genome in a 120-subunit T=1 icosahedral capsid, with a capsid protein (CP) dimer as the asymmetric unit. The atomic structure is available for four dsRNA mycovirus from different families: Saccharomyces cerevisiae virus L-A (ScV-L-A), Penicillium chrysogenum virus (PcV), Penicillium stoloniferum virus F (PsV-F), and Rosellinia necatrix quadrivirus 1 (RnQV1). Their capsids show structural variations of the same framework, with asymmetric or symmetric CP dimers respectively for ScV-L-A and PsV-F, dimers of similar domains of a single CP for PcV, or of two different proteins for RnQV1. The CP dimer is the building block, and assembly proceeds through dimers of dimers or pentamers of dimers, in which the genome is packed as ssRNA by interaction with CP and/or viral polymerase. These capsids remain structurally undisturbed throughout the viral cycle. The T=1 capsid participates in RNA synthesis, organizing the viral polymerase (1-2 copies) and a single loosely packaged genome segment. It also acts as a molecular sieve, to allow the passage of viral transcripts and nucleotides, but to prevent triggering of host defense mechanisms. Due to the close mycovirus-host relationship, CP evolved to allocate peptide insertions with enzyme activity, as reflected in a rough outer capsid surface.
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Affiliation(s)
- Carlos P Mata
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain; Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Javier M Rodríguez
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain
| | - Nobuhiro Suzuki
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan
| | - José R Castón
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain.
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Luque D, Castón JR. Cryo-electron microscopy for the study of virus assembly. Nat Chem Biol 2020; 16:231-239. [PMID: 32080621 DOI: 10.1038/s41589-020-0477-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 01/13/2020] [Indexed: 12/11/2022]
Abstract
Although viruses are extremely diverse in shape and size, evolution has led to a limited number of viral classes or lineages, which is probably linked to the assembly constraints of a viable capsid. Viral assembly mechanisms are restricted to two general pathways, (i) co-assembly of capsid proteins and single-stranded nucleic acids and (ii) a sequential mechanism in which scaffolding-mediated capsid precursor assembly is followed by genome packaging. Cryo-electron microscopy (cryo-EM) and cryo-electron tomography (cryo-ET), which are revolutionizing structural biology, are central to determining the high-resolution structures of many viral assemblies as well as those of assembly intermediates. This wealth of cryo-EM data has also led to the development and redesign of virus-based platforms for biomedical and biotechnological applications. In this Review, we will discuss recent viral assembly analyses by cryo-EM and cryo-ET showing how natural assembly mechanisms are used to encapsulate heterologous cargos including chemicals, enzymes, and/or nucleic acids for a variety of nanotechnological applications.
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Affiliation(s)
- Daniel Luque
- Centro Nacional de Microbiología/ISCIII, Majadahonda, Madrid, Spain
| | - José R Castón
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Campus Cantoblanco, Madrid, Spain.
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Konevtsova OV, Roshal DS, Lošdorfer BoŽič A, Podgornik R, Rochal S. Hidden symmetry of the anomalous bluetongue virus capsid and its role in the infection process. SOFT MATTER 2019; 15:7663-7671. [PMID: 31490506 DOI: 10.1039/c9sm01335k] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Clear understanding of the principles that control the arrangement of proteins and their self-assembly into viral shells is very important for the development of antiviral strategies. Here we consider the structural peculiarities and hidden symmetry of the anomalous bluetongue virus (BTV) capsid. Each of its three concentric shells violates the paradigmatic geometrical model of Caspar and Klug, which is otherwise well suited to describe most of the known icosahedral viral shells. As we show, three icosahedral spherical lattices, which are commensurate with each other and possess locally hexagonal (primitive or honeycomb) order, underlie the proteinaceous shells of the BTV capsid. This interpretation of the multishelled envelope allows us to discuss the so-called "symmetry mismatch" between its layers. We also analyze the structural stability of the considered spherical lattices on the basis of the classical theory of spherical packing and relate the proximity of the outer spherical lattice to destabilization with the fact that during infection of the cell VP2 trimers are detached from the surface of the BTV capsid. An electrostatic mechanism that can assist in this detachment is discussed in detail.
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Affiliation(s)
- Olga V Konevtsova
- Physics Faculty, Southern Federal University, Rostov-on-Don, Russia.
| | - Daria S Roshal
- Physics Faculty, Southern Federal University, Rostov-on-Don, Russia.
| | - AnŽe Lošdorfer BoŽič
- Department of Theoretical Physics, JoŽef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Rudolf Podgornik
- Department of Theoretical Physics, JoŽef Stefan Institute, SI-1000 Ljubljana, Slovenia and Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia and School of Physical Sciences and Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Sergey Rochal
- Physics Faculty, Southern Federal University, Rostov-on-Don, Russia.
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Twarock R, Luque A. Structural puzzles in virology solved with an overarching icosahedral design principle. Nat Commun 2019; 10:4414. [PMID: 31562316 PMCID: PMC6765026 DOI: 10.1038/s41467-019-12367-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 09/03/2019] [Indexed: 11/09/2022] Open
Abstract
Viruses have evolved protein containers with a wide spectrum of icosahedral architectures to protect their genetic material. The geometric constraints defining these container designs, and their implications for viral evolution, are open problems in virology. The principle of quasi-equivalence is currently used to predict virus architecture, but improved imaging techniques have revealed increasing numbers of viral outliers. We show that this theory is a special case of an overarching design principle for icosahedral, as well as octahedral, architectures that can be formulated in terms of the Archimedean lattices and their duals. These surface structures encompass different blueprints for capsids with the same number of structural proteins, as well as for capsid architectures formed from a combination of minor and major capsid proteins, and are recurrent within viral lineages. They also apply to other icosahedral structures in nature, and offer alternative designs for man-made materials and nanocontainers in bionanotechnology.
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Affiliation(s)
- Reidun Twarock
- Departments of Mathematics and Biology, York Cross-disciplinary Centre for Systems Analysis, University of York, York, YO10 5GE, UK.
| | - Antoni Luque
- Department of Mathematics and Statistics, Viral Information Institute, and Computational Science Research Center, San Diego State University, 5500 Campanile Drive, San Diego, CA, 92182-7720, USA.
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Mäntynen S, Sundberg LR, Oksanen HM, Poranen MM. Half a Century of Research on Membrane-Containing Bacteriophages: Bringing New Concepts to Modern Virology. Viruses 2019; 11:E76. [PMID: 30669250 PMCID: PMC6356626 DOI: 10.3390/v11010076] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 01/15/2019] [Accepted: 01/16/2019] [Indexed: 12/14/2022] Open
Abstract
Half a century of research on membrane-containing phages has had a major impact on virology, providing new insights into virus diversity, evolution and ecological importance. The recent revolutionary technical advances in imaging, sequencing and lipid analysis have significantly boosted the depth and volume of knowledge on these viruses. This has resulted in new concepts of virus assembly, understanding of virion stability and dynamics, and the description of novel processes for viral genome packaging and membrane-driven genome delivery to the host. The detailed analyses of such processes have given novel insights into DNA transport across the protein-rich lipid bilayer and the transformation of spherical membrane structures into tubular nanotubes, resulting in the description of unexpectedly dynamic functions of the membrane structures. Membrane-containing phages have provided a framework for understanding virus evolution. The original observation on membrane-containing bacteriophage PRD1 and human pathogenic adenovirus has been fundamental in delineating the concept of "viral lineages", postulating that the fold of the major capsid protein can be used as an evolutionary fingerprint to trace long-distance evolutionary relationships that are unrecognizable from the primary sequences. This has brought the early evolutionary paths of certain eukaryotic, bacterial, and archaeal viruses together, and potentially enables the reorganization of the nearly immeasurable virus population (~1 × 1031) on Earth into a reasonably low number of groups representing different architectural principles. In addition, the research on membrane-containing phages can support the development of novel tools and strategies for human therapy and crop protection.
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Affiliation(s)
- Sari Mäntynen
- Center of Excellence in Biological Interactions, Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, FI-40014 Jyväskylä, Finland.
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA.
| | - Lotta-Riina Sundberg
- Center of Excellence in Biological Interactions, Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, FI-40014 Jyväskylä, Finland.
| | - Hanna M Oksanen
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, FI-00014 Helsinki, Finland.
| | - Minna M Poranen
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, FI-00014 Helsinki, Finland.
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San Martín C. Virus Maturation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1215:129-158. [DOI: 10.1007/978-3-030-14741-9_7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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16
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Sato Y, Castón JR, Suzuki N. The biological attributes, genome architecture and packaging of diverse multi-component fungal viruses. Curr Opin Virol 2018; 33:55-65. [DOI: 10.1016/j.coviro.2018.07.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 06/29/2018] [Accepted: 07/05/2018] [Indexed: 12/19/2022]
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Capsid Structure of dsRNA Fungal Viruses. Viruses 2018; 10:v10090481. [PMID: 30205532 PMCID: PMC6164181 DOI: 10.3390/v10090481] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 09/05/2018] [Accepted: 09/05/2018] [Indexed: 01/27/2023] Open
Abstract
Most fungal, double-stranded (ds) RNA viruses lack an extracellular life cycle stage and are transmitted by cytoplasmic interchange. dsRNA mycovirus capsids are based on a 120-subunit T = 1 capsid, with a dimer as the asymmetric unit. These capsids, which remain structurally undisturbed throughout the viral cycle, nevertheless, are dynamic particles involved in the organization of the viral genome and the viral polymerase necessary for RNA synthesis. The atomic structure of the T = 1 capsids of four mycoviruses was resolved: the L-A virus of Saccharomyces cerevisiae (ScV-L-A), Penicillium chrysogenum virus (PcV), Penicillium stoloniferum virus F (PsV-F), and Rosellinia necatrix quadrivirus 1 (RnQV1). These capsids show structural variations of the same framework, with 60 asymmetric or symmetric homodimers for ScV-L-A and PsV-F, respectively, monomers with a duplicated similar domain for PcV, and heterodimers of two different proteins for RnQV1. Mycovirus capsid proteins (CP) share a conserved α-helical domain, although the latter may carry different peptides inserted at preferential hotspots. Insertions in the CP outer surface are likely associated with enzymatic activities. Within the capsid, fungal dsRNA viruses show a low degree of genome compaction compared to reoviruses, and contain one to two copies of the RNA-polymerase complex per virion.
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18
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Oliveira LM, Ye Z, Katz A, Alimova A, Wei H, Herman GT, Gottlieb P. Component tree analysis of cystovirus φ6 nucleocapsid Cryo-EM single particle reconstructions. PLoS One 2018; 13:e0188858. [PMID: 29300742 PMCID: PMC5754084 DOI: 10.1371/journal.pone.0188858] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 11/14/2017] [Indexed: 01/10/2023] Open
Abstract
The 3-dimensional structure of the nucleocapsid (NC) of bacteriophage φ6 is described utilizing component tree analysis, a topological and geometric image descriptor. The component trees are derived from density maps of cryo-electron microscopy single particle reconstructions. Analysis determines position and occupancy of structure elements responsible for RNA packaging and transcription. Occupancy of the hexameric nucleotide triphosphorylase (P4) and RNA polymerase (P2) are found to be essentially complete in the NC. The P8 protein lattice likely fixes P4 and P2 in place during maturation. We propose that the viral procapsid (PC) is a dynamic structural intermediate where the P4 and P2 can attach and detach until held in place in mature NCs. During packaging, the PC expands to accommodate the RNA, and P2 translates from its original site near the inner 3-fold axis (20 sites) to the inner 5-fold axis (12 sites) with excess P2 positioned inside the central region of the NC.
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Affiliation(s)
- Lucas M. Oliveira
- Department of Computer Science, Graduate Center of the City University of New York, New York, NY, United States of America
| | - Ze Ye
- Department of Computer Science, Graduate Center of the City University of New York, New York, NY, United States of America
| | - Al Katz
- Physics Department, City College of New York, New York, NY, United States of America
| | - Alexandra Alimova
- City University of New York School of Medicine, City College of New York, New York, NY, United States of America
| | - Hui Wei
- City University of New York School of Medicine, City College of New York, New York, NY, United States of America
| | - Gabor T. Herman
- Department of Computer Science, Graduate Center of the City University of New York, New York, NY, United States of America
| | - Paul Gottlieb
- City University of New York School of Medicine, City College of New York, New York, NY, United States of America
- * E-mail:
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Dubankova A, Humpolickova J, Klima M, Boura E. Negative charge and membrane-tethered viral 3B cooperate to recruit viral RNA dependent RNA polymerase 3D pol. Sci Rep 2017; 7:17309. [PMID: 29230036 PMCID: PMC5725453 DOI: 10.1038/s41598-017-17621-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 11/29/2017] [Indexed: 12/28/2022] Open
Abstract
Most single stranded plus RNA viruses hijack phosphatidylinositol 4-kinases (PI4Ks) to generate membranes highly enriched in phosphatidylinositol 4-phosphate (PI4P). These membranous compartments known as webs, replication factories or replication organelles are essential for viral replication because they provide protection from the innate intracellular immune response while serving as platforms for viral replication. Using purified recombinant proteins and biomimetic model membranes we show that the nonstructural viral 3A protein is sufficient to promote membrane hyper-phosphorylation given the proper intracellular cofactors (PI4KB and ACBD3). However, our bio-mimetic in vitro reconstitution assay revealed that rather than the presence of PI4P specifically, negative charge alone is sufficient for the recruitment of 3Dpol enzymes to the surface of the lipid bilayer. Additionally, we show that membrane tethered viral 3B protein (also known as Vpg) works in combination with the negative charge to increase the efficiency of membrane recruitment of 3Dpol.
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Affiliation(s)
- Anna Dubankova
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jana Humpolickova
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic
| | - Martin Klima
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic
| | - Evzen Boura
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic.
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20
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Mata CP, Luque D, Gómez-Blanco J, Rodríguez JM, González JM, Suzuki N, Ghabrial SA, Carrascosa JL, Trus BL, Castón JR. Acquisition of functions on the outer capsid surface during evolution of double-stranded RNA fungal viruses. PLoS Pathog 2017; 13:e1006755. [PMID: 29220409 PMCID: PMC5738138 DOI: 10.1371/journal.ppat.1006755] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 12/20/2017] [Accepted: 11/16/2017] [Indexed: 11/25/2022] Open
Abstract
Unlike their counterparts in bacterial and higher eukaryotic hosts, most fungal viruses are transmitted intracellularly and lack an extracellular phase. Here we determined the cryo-EM structure at 3.7 Å resolution of Rosellinia necatrix quadrivirus 1 (RnQV1), a fungal double-stranded (ds)RNA virus. RnQV1, the type species of the family Quadriviridae, has a multipartite genome consisting of four monocistronic segments. Whereas most dsRNA virus capsids are based on dimers of a single protein, the ~450-Å-diameter, T = 1 RnQV1 capsid is built of P2 and P4 protein heterodimers, each with more than 1000 residues. Despite a lack of sequence similarity between the two proteins, they have a similar α-helical domain, the structural signature shared with the lineage of the dsRNA bluetongue virus-like viruses. Domain insertions in P2 and P4 preferential sites provide additional functions at the capsid outer surface, probably related to enzyme activity. The P2 insertion has a fold similar to that of gelsolin and profilin, two actin-binding proteins with a function in cytoskeleton metabolism, whereas the P4 insertion suggests protease activity involved in cleavage of the P2 383-residue C-terminal region, absent in the mature viral particle. Our results indicate that the intimate virus-fungus partnership has altered the capsid genome-protective and/or receptor-binding functions. Fungal virus evolution has tended to allocate enzyme activities to the virus capsid outer surface. Most fungal RNA viruses are transmitted by cytoplasmic interchange without leaving the host. We report the cryo-electron microscopy structure, at near-atomic resolution, of the double-stranded RNA Rosellinia necatrix quadrivirus 1 (RnQV1); this virus infects the fungus Rosellinia necatrix, a pathogenic ascomycete to a wide range of plants. At difference most dsRNA viruses, whose capsid is made of protein homodimers, RnQV1 is based on a single-shelled lattice built of 60 P2-P4 heterodimers. Despite a lack of sequence similarity, P2 and P4 have a similar α-helical domain, a structural signature shared with the dsRNA virus lineage. In addition to organizing the viral genome and replicative machinery, P2 and P4 have acquired new functions by inserting complex domains in preferential insertion sites. Whereas the P2 insertion domain has a fold like that of actin-binding proteins, the structure of the P4 insertion domain indicates proteolytic activity. Understanding the structure of a fungal virus capsid with enzyme activities could allow its development as nanoreactors for biotechnological application.
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Affiliation(s)
- Carlos P. Mata
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Campus Cantoblanco, Madrid, Spain
| | - Daniel Luque
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Campus Cantoblanco, Madrid, Spain
- Centro Nacional de Microbiología/ISCIII, Majadahonda, Madrid, Spain
| | - Josué Gómez-Blanco
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Campus Cantoblanco, Madrid, Spain
| | | | - José M. González
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Campus Cantoblanco, Madrid, Spain
| | | | - Said A. Ghabrial
- Department of Plant Pathology, University of Kentucky, Lexington, KY, United States of America
| | - José L. Carrascosa
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Campus Cantoblanco, Madrid, Spain
| | - Benes L. Trus
- Imaging Sciences Laboratory, CIT, NIH, Bethesda, MD, United States of America
| | - José R. Castón
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Campus Cantoblanco, Madrid, Spain
- * E-mail:
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21
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Chalupska D, Eisenreichova A, Różycki B, Rezabkova L, Humpolickova J, Klima M, Boura E. Structural analysis of phosphatidylinositol 4-kinase IIIβ (PI4KB) - 14-3-3 protein complex reveals internal flexibility and explains 14-3-3 mediated protection from degradation in vitro. J Struct Biol 2017; 200:36-44. [PMID: 28864297 DOI: 10.1016/j.jsb.2017.08.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 08/26/2017] [Accepted: 08/28/2017] [Indexed: 12/31/2022]
Abstract
Phosphatidylinositol 4-kinase IIIβ (PI4KB) is responsible for the synthesis of the Golgi and trans-Golgi network (TGN) pool of phosphatidylinositol 4-phospahte (PI4P). PI4P is the defining lipid hallmark of Golgi and TGN and also serves as a signaling lipid and as a precursor for higher phosphoinositides. In addition, PI4KB is hijacked by many single stranded plus RNA (+RNA) viruses to generate PI4P-rich membranes that serve as viral replication organelles. Given the importance of this enzyme in cells, it has to be regulated. 14-3-3 proteins bind PI4KB upon its phosphorylation by protein kinase D, however, the structural basis of PI4KB recognition by 14-3-3 proteins is unknown. Here, we characterized the PI4KB:14-3-3 protein complex biophysically and structurally. We discovered that the PI4KB:14-3-3 protein complex is tight and is formed with 2:2 stoichiometry. Surprisingly, the enzymatic activity of PI4KB is not directly modulated by 14-3-3 proteins. However, 14-3-3 proteins protect PI4KB from proteolytic degradation in vitro. Our structural analysis revealed that the PI4KB:14-3-3 protein complex is flexible but mostly within the disordered regions connecting the 14-3-3 binding site of the PI4KB with the rest of the PI4KB enzyme. It also predicted no direct modulation of PI4KB enzymatic activity by 14-3-3 proteins and that 14-3-3 binding will not interfere with PI4KB recruitment to the membrane by the ACBD3 protein. In addition, the structural analysis explains the observed protection from degradation; it revealed that several disordered regions of PI4KB become protected from proteolytical degradation upon 14-3-3 binding. All the structural predictions were subsequently biochemically validated.
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Affiliation(s)
- Dominika Chalupska
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague 6, Czech Republic
| | - Andrea Eisenreichova
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague 6, Czech Republic
| | - Bartosz Różycki
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Lenka Rezabkova
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232, Villigen PSI, Switzerland
| | - Jana Humpolickova
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague 6, Czech Republic
| | - Martin Klima
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague 6, Czech Republic
| | - Evzen Boura
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague 6, Czech Republic.
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22
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Sun Z, El Omari K, Sun X, Ilca SL, Kotecha A, Stuart DI, Poranen MM, Huiskonen JT. Double-stranded RNA virus outer shell assembly by bona fide domain-swapping. Nat Commun 2017; 8:14814. [PMID: 28287099 PMCID: PMC5355851 DOI: 10.1038/ncomms14814] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 01/26/2017] [Indexed: 12/30/2022] Open
Abstract
Correct outer protein shell assembly is a prerequisite for virion infectivity in many multi-shelled dsRNA viruses. In the prototypic dsRNA bacteriophage φ6, the assembly reaction is promoted by calcium ions but its biomechanics remain poorly understood. Here, we describe the near-atomic resolution structure of the φ6 double-shelled particle. The outer T=13 shell protein P8 consists of two alpha-helical domains joined by a linker, which allows the trimer to adopt either a closed or an open conformation. The trimers in an open conformation swap domains with each other. Our observations allow us to propose a mechanistic model for calcium concentration regulated outer shell assembly. Furthermore, the structure provides a prime exemplar of bona fide domain-swapping. This leads us to extend the theory of domain-swapping from the level of monomeric subunits and multimers to closed spherical shells, and to hypothesize a mechanism by which closed protein shells may arise in evolution. Double-shelled bacteriophage φ6 is a well-studied model system used to understand assembly of dsRNA viruses. Here the authors report a near-atomic resolution cryo-EM structure of φ6 and propose a model for the structural transitions occurring in the outer shell during genome packaging.
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Affiliation(s)
- Zhaoyang Sun
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Kamel El Omari
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Xiaoyu Sun
- Department of Biosciences, University of Helsinki, Viikinkaari 9, Helsinki 00014, Finland
| | - Serban L Ilca
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Abhay Kotecha
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - David I Stuart
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Minna M Poranen
- Department of Biosciences, University of Helsinki, Viikinkaari 9, Helsinki 00014, Finland
| | - Juha T Huiskonen
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK.,Department of Biosciences, University of Helsinki, Viikinkaari 9, Helsinki 00014, Finland
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23
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Alphonse S, Ghose R. Cystoviral RNA-directed RNA polymerases: Regulation of RNA synthesis on multiple time and length scales. Virus Res 2017; 234:135-152. [PMID: 28104452 PMCID: PMC5476504 DOI: 10.1016/j.virusres.2017.01.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 01/04/2017] [Accepted: 01/09/2017] [Indexed: 12/18/2022]
Abstract
Role of the RNA polymerase in the cystoviral life-cycle. Spatio-temporal regulation of RNA synthesis in cystoviruses. Emerging role of conformational dynamics in polymerase function.
P2, an RNA-directed RNA polymerase (RdRP), is encoded on the largest of the three segments of the double-stranded RNA genome of cystoviruses. P2 performs the dual tasks of replication and transcription de novo on single-stranded RNA templates, and plays a critical role in the viral life-cycle. Work over the last few decades has yielded a wealth of biochemical and structural information on the functional regulation of P2, on its role in the spatiotemporal regulation of RNA synthesis and its variability across the Cystoviridae family. These range from atomic resolution snapshots of P2 trapped in functionally significant states, in complex with catalytic/structural metal ions, polynucleotide templates and substrate nucleoside triphosphates, to P2 in the context of viral capsids providing structural insight into the assembly of supramolecular complexes and regulatory interactions therein. They include in vitro biochemical studies using P2 purified to homogeneity and in vivo studies utilizing infectious core particles. Recent advances in experimental techniques have also allowed access to the temporal dimension and enabled the characterization of dynamics of P2 on the sub-nanosecond to millisecond timescale through measurements of nuclear spin relaxation in solution and single molecule studies of transcription from seconds to minutes. Below we summarize the most significant results that provide critical insight into the role of P2 in regulating RNA synthesis in cystoviruses.
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Affiliation(s)
- Sébastien Alphonse
- Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031, United States.
| | - Ranajeet Ghose
- Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031, United States; Graduate Programs in Biochemistry, The Graduate Center of CUNY, New York, NY 10016, United States; Graduate Programs in Chemistry, The Graduate Center of CUNY, New York, NY 10016, United States; Graduate Programs in Physics, The Graduate Center of CUNY, New York, NY 10016, United States.
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24
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Humpolickova J, Mejdrová I, Matousova M, Nencka R, Boura E. Fluorescent Inhibitors as Tools To Characterize Enzymes: Case Study of the Lipid Kinase Phosphatidylinositol 4-Kinase IIIβ (PI4KB). J Med Chem 2016; 60:119-127. [PMID: 28004946 DOI: 10.1021/acs.jmedchem.6b01466] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The lipid kinase phosphatidylinositol 4-kinase IIIβ (PI4KB) is an essential host factor for many positive-sense single-stranded RNA (+RNA) viruses including human pathogens hepatitis C virus (HCV), Severe acute respiratory syndrome (SARS), coxsackie viruses, and rhinoviruses. Inhibitors of PI4KB are considered to be potential broad-spectrum virostatics, and it is therefore critical to develop a biochemical understanding of the kinase. Here, we present highly potent and selective fluorescent inhibitors that we show to be useful chemical biology tools especially in determination of dissociation constants. Moreover, we show that the coumarin-labeled inhibitor can be used to image PI4KB in cells using fluorescence-lifetime imaging microscopy (FLIM) microscopy.
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Affiliation(s)
- Jana Humpolickova
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i , Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
| | - Ivana Mejdrová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i , Flemingovo nám. 2, 166 10 Prague 6, Czech Republic.,Department of Chemistry of Natural Compounds, Institute of Chemical Technology Prague , Technicka 5, Prague 166 28, Czech Republic
| | - Marika Matousova
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i , Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
| | - Radim Nencka
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i , Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
| | - Evzen Boura
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i , Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
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25
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Heterodimers as the Structural Unit of the T=1 Capsid of the Fungal Double-Stranded RNA Rosellinia necatrix Quadrivirus 1. J Virol 2016; 90:11220-11230. [PMID: 27707923 DOI: 10.1128/jvi.01013-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 09/29/2016] [Indexed: 02/07/2023] Open
Abstract
Most double-stranded RNA (dsRNA) viruses are transcribed and replicated in a specialized icosahedral capsid with a T=1 lattice consisting of 60 asymmetric capsid protein (CP) dimers. These capsids help to organize the viral genome and replicative complex(es). They also act as molecular sieves that isolate the virus genome from host defense mechanisms and allow the passage of nucleotides and viral transcripts. Rosellinia necatrix quadrivirus 1 (RnQV1), the type species of the family Quadriviridae, is a dsRNA fungal virus with a multipartite genome consisting of four monocistronic segments (segments 1 to 4). dsRNA-2 and dsRNA-4 encode two CPs (P2 and P4, respectively), which coassemble into ∼450-Å-diameter capsids. We used three-dimensional cryo-electron microscopy combined with complementary biophysical techniques to determine the structures of RnQV1 virion strains W1075 and W1118. RnQV1 has a quadripartite genome, and the capsid is based on a single-shelled T=1 lattice built of P2-P4 dimers. Whereas the RnQV1-W1118 capsid is built of full-length CP, P2 and P4 of RnQV1-W1075 are cleaved into several polypeptides, maintaining the capsid structural organization. RnQV1 heterodimers have a quaternary organization similar to that of homodimers of reoviruses and other dsRNA mycoviruses. The RnQV1 capsid is the first T=1 capsid with a heterodimer as an asymmetric unit reported to date and follows the architectural principle for dsRNA viruses that a 120-subunit capsid is a conserved assembly that supports dsRNA replication and organization. IMPORTANCE Given their importance to health, members of the family Reoviridae are the basis of most structural and functional studies and provide much of our knowledge of dsRNA viruses. Analysis of bacterial, protozoal, and fungal dsRNA viruses has improved our understanding of their structure, function, and evolution, as well. Here, we studied a dsRNA virus that infects the fungus Rosellinia necatrix, an ascomycete that is pathogenic to a wide range of plants. Using three-dimensional cryo-electron microscopy and analytical ultracentrifugation analysis, we determined the structure and stoichiometry of Rosellinia necatrix quadrivirus 1 (RnQV1). The RnQV1 capsid is a T=1 capsid with 60 heterodimers as the asymmetric units. The large amount of genetic information used by RnQV1 to construct a simple T=1 capsid is probably related to the numerous virus-host and virus-virus interactions that it must face in its life cycle, which lacks an extracellular phase.
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26
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Baumlova A, Gregor J, Boura E. The structural basis for calcium inhibition of lipid kinase PI4K IIalpha and comparison with the apo state. Physiol Res 2016; 65:987-993. [PMID: 27539108 DOI: 10.33549/physiolres.933344] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PI4K IIalpha is a critical enzyme for the maintenance of Golgi and is also known to function in the synaptic vesicles. The product of its catalytical function, phosphatidylinositol 4-phosphate (PI4P), is an important lipid molecule because it is a hallmark of the Golgi and TGN, is directly recognized by many proteins and also serves as a precursor molecule for synthesis of higher phosphoinositides. Here, we report crystal structures of PI4K IIalpha enzyme in the apo-state and inhibited by calcium. The apo-structure reveals a surprising rigidity of the active site residues important for catalytic activity. The structure of calcium inhibited kinase reveals how calcium locks ATP in the active site.
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Affiliation(s)
- A Baumlova
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic.
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27
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Ilca SL, Kotecha A, Sun X, Poranen MM, Stuart DI, Huiskonen JT. Localized reconstruction of subunits from electron cryomicroscopy images of macromolecular complexes. Nat Commun 2015; 6:8843. [PMID: 26534841 PMCID: PMC4667630 DOI: 10.1038/ncomms9843] [Citation(s) in RCA: 174] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 10/08/2015] [Indexed: 12/12/2022] Open
Abstract
Electron cryomicroscopy can yield near-atomic resolution structures of highly ordered macromolecular complexes. Often however some subunits bind in a flexible manner, have different symmetry from the rest of the complex, or are present in sub-stoichiometric amounts, limiting the attainable resolution. Here we report a general method for the localized three-dimensional reconstruction of such subunits. After determining the particle orientations, local areas corresponding to the subunits can be extracted and treated as single particles. We demonstrate the method using three examples including a flexible assembly and complexes harbouring subunits with either partial occupancy or mismatched symmetry. Most notably, the method allows accurate fitting of the monomeric RNA-dependent RNA polymerase bound at the threefold axis of symmetry inside a viral capsid, revealing for the first time its exact orientation and interactions with the capsid proteins. Localized reconstruction is expected to provide novel biological insights in a range of challenging biological systems. Electron cryomicroscopy can allow the elucidation of macromolecular structures; however, mismatches in symmetry between different components limit the attainable resolution. Here, the authors set out a computational method for extracting and retaining information from such components.
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28
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Veesler D, Kearney BM, Johnson JE. Integration of X-ray crystallography and electron cryo-microscopy in the analysis of virus structure and function. CRYSTALLOGR REV 2015. [DOI: 10.1080/0889311x.2015.1038530] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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29
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Miyazaki N, Salaipeth L, Kanematsu S, Iwasaki K, Suzuki N. Megabirnavirus structure reveals a putative 120-subunit capsid formed by asymmetrical dimers with distinctive large protrusions. J Gen Virol 2015; 96:2435-2441. [DOI: 10.1099/vir.0.000182] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Naoyuki Miyazaki
- National Institute for Physiological Sciences, 38 Nishigonaka, Myodaiji, Okazaki, Aichi, 444-8585, Japan
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Lakha Salaipeth
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, 710-0046, Japan
| | - Satoko Kanematsu
- NARO Institute of Fruit Tree Science, 92 Shimokuriyagawa, Morioka, Iwate, 020-0123, Japan
| | - Kenji Iwasaki
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Nobuhiro Suzuki
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, 710-0046, Japan
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30
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Klima M, Baumlova A, Chalupska D, Hřebabecký H, Dejmek M, Nencka R, Boura E. The high-resolution crystal structure of phosphatidylinositol 4-kinase IIβ and the crystal structure of phosphatidylinositol 4-kinase IIα containing a nucleoside analogue provide a structural basis for isoform-specific inhibitor design. ACTA ACUST UNITED AC 2015; 71:1555-63. [PMID: 26143926 DOI: 10.1107/s1399004715009505] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 05/18/2015] [Indexed: 11/10/2022]
Abstract
Phosphatidylinositol 4-phosphate (PI4P) is the most abundant monophosphoinositide in eukaryotic cells. Humans have four phosphatidylinositol 4-kinases (PI4Ks) that synthesize PI4P, among which are PI4K IIβ and PI4K IIα. In this study, two crystal structures are presented: the structure of human PI4K IIβ and the structure of PI4K IIα containing a nucleoside analogue. The former, a complex with ATP, is the first high-resolution (1.9 Å) structure of a PI4K. These structures reveal new details such as high conformational heterogeneity of the lateral hydrophobic pocket of the C-lobe and together provide a structural basis for isoform-specific inhibitor design.
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Affiliation(s)
- Martin Klima
- Department of Biochemistry, Institute of Organic Chemistry and Biochemistry, Flemingovo nam. 2, 166 10 Prague, Czech Republic
| | - Adriana Baumlova
- Department of Biochemistry, Institute of Organic Chemistry and Biochemistry, Flemingovo nam. 2, 166 10 Prague, Czech Republic
| | - Dominika Chalupska
- Department of Biochemistry, Institute of Organic Chemistry and Biochemistry, Flemingovo nam. 2, 166 10 Prague, Czech Republic
| | - Hubert Hřebabecký
- Department of Biochemistry, Institute of Organic Chemistry and Biochemistry, Flemingovo nam. 2, 166 10 Prague, Czech Republic
| | - Milan Dejmek
- Department of Biochemistry, Institute of Organic Chemistry and Biochemistry, Flemingovo nam. 2, 166 10 Prague, Czech Republic
| | - Radim Nencka
- Department of Biochemistry, Institute of Organic Chemistry and Biochemistry, Flemingovo nam. 2, 166 10 Prague, Czech Republic
| | - Evzen Boura
- Department of Biochemistry, Institute of Organic Chemistry and Biochemistry, Flemingovo nam. 2, 166 10 Prague, Czech Republic
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31
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San Martín C. Transmission electron microscopy and the molecular structure of icosahedral viruses. Arch Biochem Biophys 2015; 581:59-67. [PMID: 26072114 DOI: 10.1016/j.abb.2015.06.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 06/01/2015] [Accepted: 06/04/2015] [Indexed: 11/16/2022]
Abstract
The field of structural virology developed in parallel with methodological advances in X-ray crystallography and cryo-electron microscopy. At the end of the 1970s, crystallography yielded the first high resolution structure of an icosahedral virus, the T=3 tomato bushy stunt virus at 2.9Å. It took longer to reach near-atomic resolution in three-dimensional virus maps derived from electron microscopy data, but this was finally achieved, with the solution of complex icosahedral capsids such as the T=25 human adenovirus at ∼3.5Å. Both techniques now work hand-in-hand to determine those aspects of virus assembly and biology that remain unclear. This review examines the trajectory followed by EM imaging techniques in showing the molecular structure of icosahedral viruses, from the first two-dimensional negative staining images of capsids to the latest sophisticated techniques that provide high resolution three-dimensional data, or snapshots of the conformational changes necessary to complete the infectious cycle.
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Affiliation(s)
- Carmen San Martín
- Department of Macromolecular Structure and NanoBioMedicine Initiative, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, 28049 Madrid, Spain.
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32
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Mejdrová I, Chalupská D, Kögler M, Šála M, Plačková P, Baumlová A, Hřebabecký H, Procházková E, Dejmek M, Guillon R, Strunin D, Weber J, Lee G, Birkus G, Mertlíková-Kaiserová H, Boura E, Nencka R. Highly Selective Phosphatidylinositol 4-Kinase IIIβ Inhibitors and Structural Insight into Their Mode of Action. J Med Chem 2015; 58:3767-93. [PMID: 25897704 DOI: 10.1021/acs.jmedchem.5b00499] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Phosphatidylinositol 4-kinase IIIβ is a cellular lipid kinase pivotal to pathogenesis of various RNA viruses. These viruses hijack the enzyme in order to modify the structure of intracellular membranes and use them for the construction of functional replication machinery. Selective inhibitors of this enzyme are potential broad-spectrum antiviral agents, as inhibition of this enzyme results in the arrest of replication of PI4K IIIβ-dependent viruses. Herein, we report a detailed study of novel selective inhibitors of PI4K IIIβ, which exert antiviral activity against a panel of single-stranded positive-sense RNA viruses. Our crystallographic data show that the inhibitors occupy the binding site for the adenine ring of the ATP molecule and therefore prevent the phosphorylation reaction.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Gary Lee
- ‡Gilead Sciences, Inc., 333 Lakeside Drive, Foster City, California 94404, United States
| | - Gabriel Birkus
- ‡Gilead Sciences, Inc., 333 Lakeside Drive, Foster City, California 94404, United States
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33
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Mäntynen S, Laanto E, Kohvakka A, Poranen MM, Bamford JKH, Ravantti JJ. New enveloped dsRNA phage from freshwater habitat. J Gen Virol 2015; 96:1180-1189. [PMID: 25614591 DOI: 10.1099/vir.0.000063] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 01/15/2015] [Indexed: 12/27/2022] Open
Abstract
Cystoviridae is a family of bacteriophages with a tri-segmented dsRNA genome enclosed in a tri-layered virion structure. Here, we present a new putative member of the Cystoviridae family, bacteriophage ϕNN. ϕNN was isolated from a Finnish lake in contrast to the previously identified cystoviruses, which originate from various legume samples collected in the USA. The nucleotide sequence of the virus reveals a strong genetic similarity (~80 % for the L-segments, ~55 % for the M-segments and ~84 % for the S-segments) to Pseudomonas phage ϕ6, the type member of the virus family. However, the relationship between ϕNN and other cystoviruses is more distant. In general, proteins located in the internal parts of the virion were more conserved than those exposed on the virion surface, a phenomenon previously reported among eukaryotic dsRNA viruses. Structural models of several putative ϕNN proteins propose that cystoviral structures are highly conserved.
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Affiliation(s)
- Sari Mäntynen
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Elina Laanto
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Annika Kohvakka
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Minna M Poranen
- Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Jaana K H Bamford
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Janne J Ravantti
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.,Department of Biosciences, University of Helsinki, Helsinki, Finland.,Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
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34
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Różycki B, Boura E. Large, dynamic, multi-protein complexes: a challenge for structural biology. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:463103. [PMID: 25335513 DOI: 10.1088/0953-8984/26/46/463103] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Structural biology elucidates atomic structures of macromolecules such as proteins, DNA, RNA, and their complexes to understand the basic mechanisms of their functions. Among proteins that pose the most difficult problems to current efforts are those which have several large domains connected by long, flexible polypeptide segments. Although abundant and critically important in biological cells, such proteins have proven intractable by conventional techniques. This gap has recently led to the advancement of hybrid methods that use state-of-the-art computational tools to combine complementary data from various high- and low-resolution experiments. In this review, we briefly discuss the individual experimental techniques to illustrate their strengths and limitations, and then focus on the use of hybrid methods in structural biology. We describe how representative structures of dynamic multi-protein complexes are obtained utilizing the EROS hybrid method that we have co-developed.
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Affiliation(s)
- Bartosz Różycki
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland
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35
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Abstract
As they mature, many capsids undergo massive conformational changes that transform their stability, reactivity, and capacity for DNA. In some cases, maturation proceeds via one or more intermediate states. These structures represent local minima in a rich energy landscape that combines contributions from subunit folding, association of subunits into capsomers, and intercapsomer interactions. We have used scanning calorimetry and cryo-electron microscopy to explore the range of capsid conformations accessible to bacteriophage HK97. To separate conformational effects from those associated with covalent cross-linking (a stabilization mechanism of HK97), a cross-link-incompetent mutant was used. The mature capsid Head I undergoes an endothermic phase transition at 60°C in which it shrinks by 7%, primarily through changes in its hexamer conformation. The transition is reversible, with a half-life of ~3 min; however, >50% of reverted capsids are severely distorted or ruptured. This observation implies that such damage is a potential hazard of large-scale structural changes such as those involved in maturation. Assuming that the risk is lower for smaller changes, this suggests a rationalization for the existence of metastable intermediates: that they serve as stepping stones that preserve capsid integrity as it switches between the radically different conformations of its precursor and mature states. Large-scale conformational changes are widespread in virus maturation and infection processes. These changes are accompanied by the release of conformational free energy as the virion (or fusogenic glycoprotein) switches from a precursor state to its mature state. Each state corresponds to a local minimum in an energy landscape. The conformational changes in capsid maturation are so radical that the question arises of how maturing capsids avoid being torn apart. Offering proof of principle, severe damage is inflicted when a bacteriophage HK97 capsid reverts from the (nonphysiological) state that it enters when heated past 60°C. We suggest that capsid proteins have been selected in part by the criterion of being able to avoid sustaining collateral damage as they mature. One way of achieving this—as with the HK97 capsid—involves breaking the overall transition down into several smaller steps in which the risk of damage is reduced.
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36
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Baumlova A, Chalupska D, Róźycki B, Jovic M, Wisniewski E, Klima M, Dubankova A, Kloer DP, Nencka R, Balla T, Boura E. The crystal structure of the phosphatidylinositol 4-kinase IIα. EMBO Rep 2014; 15:1085-92. [PMID: 25168678 DOI: 10.15252/embr.201438841] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Phosphoinositides are a class of phospholipids generated by the action of phosphoinositide kinases with key regulatory functions in eukaryotic cells. Here, we present the atomic structure of phosphatidylinositol 4-kinase type IIα (PI4K IIα), in complex with ATP solved by X-ray crystallography at 2.8 Å resolution. The structure revealed a non-typical kinase fold that could be divided into N- and C-lobes with the ATP binding groove located in between. Surprisingly, a second ATP was found in a lateral hydrophobic pocket of the C-lobe. Molecular simulations and mutagenesis analysis revealed the membrane binding mode and the putative function of the hydrophobic pocket. Taken together, our results suggest a mechanism of PI4K IIα recruitment, regulation, and function at the membrane.
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Affiliation(s)
- Adriana Baumlova
- Institute of Organic Chemistry and Biochemistry AS CR, Prague, Czech Republic
| | - Dominika Chalupska
- Institute of Organic Chemistry and Biochemistry AS CR, Prague, Czech Republic
| | - Bartosz Róźycki
- Institute of Physics Polish Academy of Sciences, Warsaw, Poland
| | - Marko Jovic
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, NICHD NIH, Bethesda, MD, USA
| | - Eva Wisniewski
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, NICHD NIH, Bethesda, MD, USA
| | - Martin Klima
- Institute of Organic Chemistry and Biochemistry AS CR, Prague, Czech Republic
| | - Anna Dubankova
- Institute of Organic Chemistry and Biochemistry AS CR, Prague, Czech Republic
| | - Daniel P Kloer
- Syngenta Jealott's Hill Internation Research Centre, Bracknell, UK
| | - Radim Nencka
- Institute of Organic Chemistry and Biochemistry AS CR, Prague, Czech Republic
| | - Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, NICHD NIH, Bethesda, MD, USA
| | - Evzen Boura
- Institute of Organic Chemistry and Biochemistry AS CR, Prague, Czech Republic
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37
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Alphonse S, Arnold JJ, Bhattacharya S, Wang H, Kloss B, Cameron CE, Ghose R. Cystoviral polymerase complex protein P7 uses its acidic C-terminal tail to regulate the RNA-directed RNA polymerase P2. J Mol Biol 2014; 426:2580-93. [PMID: 24813120 DOI: 10.1016/j.jmb.2014.04.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 04/25/2014] [Accepted: 04/30/2014] [Indexed: 01/24/2023]
Abstract
In bacteriophages of the cystovirus family, the polymerase complex (PX) encodes a 75-kDa RNA-directed RNA polymerase (P2) that transcribes the double-stranded RNA genome. Also a constituent of the PX is the essential protein P7 that, in addition to accelerating PX assembly and facilitating genome packaging, plays a regulatory role in transcription. Deletion of P7 from the PX leads to aberrant plus-strand synthesis suggesting its influence on the transcriptase activity of P2. Here, using solution NMR techniques and the P2 and P7 proteins from cystovirus ϕ12, we demonstrate their largely electrostatic interaction in vitro. Chemical shift perturbations on P7 in the presence of P2 suggest that this interaction involves the dynamic C-terminal tail of P7, more specifically an acidic cluster therein. Patterns of chemical shift changes induced on P2 by the P7 C-terminus resemble those seen in the presence of single-stranded RNA suggesting similarities in binding. This association between P2 and P7 reduces the affinity of the former toward template RNA and results in its decreased activity both in de novo RNA synthesis and in extending a short primer. Given the presence of C-terminal acidic tracts on all cystoviral P7 proteins, the electrostatic nature of the P2/P7 interaction is likely conserved within the family and could constitute a mechanism through which P7 regulates transcription in cystoviruses.
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Affiliation(s)
- Sébastien Alphonse
- Department of Chemistry, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA
| | - Jamie J Arnold
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Shibani Bhattacharya
- The New York Structural Biology Center, 89 Convent Avenue, New York, NY 10027, USA
| | - Hsin Wang
- Department of Chemistry, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA
| | - Brian Kloss
- The New York Structural Biology Center, 89 Convent Avenue, New York, NY 10027, USA
| | - Craig E Cameron
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Ranajeet Ghose
- Department of Chemistry, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA; The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, NY 10016, USA.
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38
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Electrostatic interactions drive the self-assembly and the transcription activity of the Pseudomonas phage ϕ6 procapsid. J Virol 2014; 88:7112-6. [PMID: 24719418 DOI: 10.1128/jvi.00467-14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Assembly of an empty procapsid is a crucial step in the formation of many complex viruses. Here, we used the self-assembly system of the double-stranded RNA bacteriophage ϕ6 to study the role of electrostatic interactions in a scaffolding-independent procapsid assembly pathway. We demonstrate that ϕ6 procapsid assembly is sensitive to salt at both the nucleation and postnucleation steps. Furthermore, we observed that the salt sensitivity of ϕ6 procapsid-directed transcription is reversible.
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39
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Abstract
Cystoviruses are dsRNA viruses that infect bacteria and include bacteriophages Φ8 and Φ6. In this issue of Structure, El Omari and colleagues and Nemecek and colleagues report crystal structures of capsid protein P1 pentamers found in procapsid cores of Φ8 and Φ6. The two structures show a striking resemblance in the absence of sequence similarity and offer new mechanistic and evolutionary insights.
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40
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Sun X, Pirttimaa MJ, Bamford DH, Poranen MM. Rescue of maturation off-pathway products in the assembly of Pseudomonas phage φ 6. J Virol 2013; 87:13279-86. [PMID: 24089550 PMCID: PMC3838280 DOI: 10.1128/jvi.02285-13] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 09/23/2013] [Indexed: 12/30/2022] Open
Abstract
Many complex viruses use an assembly pathway in which their genome is packaged into an empty procapsid which subsequently matures into its final expanded form. We utilized Pseudomonas phage 6, a well-established virus assembly model, to probe the plasticity of the procapsid maturation pathway. The 6 packaging nucleoside triphosphatase (NTPase), which powers sequential translocation of the three viral genomic single-stranded RNA molecules to the procapsid during capsid maturation, is part of the mature 6 virion but may spontaneously be dissociated from the procapsid shell. We demonstrate that the dissociation of NTPase subunits results in premature capsid expansion, which is detected as a change in the sedimentation velocity and as defects in RNA packaging and transcription activity. However, this dead-end conformation of the procapsids was rescued by the addition of purified NTPase hexamers, which efficiently associated on the NTPase-deficient particles and subsequently drove their contraction to the compact naive conformation. The resulting particles regained their biological and enzymatic activities, directing them into a productive maturation pathway. These observations imply that the maturation pathways of complex viruses may contain reversible steps that allow the rescue of the off-pathway conformation in an overall unidirectional virion assembly pathway. Furthermore, we provide direct experimental evidence that particles which have different physical properties (distinct sedimentation velocities and conformations) display different stages of the genome packaging program and show that the transcriptional activity of the 6 procapsids correlates with the number of associated NTPase subunits.
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Affiliation(s)
- Xiaoyu Sun
- Department of Biosciences
- Institute of Biotechnology, University of Helsinki, Viikki Biocenter, Helsinki, Finland
| | - Markus J. Pirttimaa
- Department of Biosciences
- Institute of Biotechnology, University of Helsinki, Viikki Biocenter, Helsinki, Finland
| | - Dennis H. Bamford
- Department of Biosciences
- Institute of Biotechnology, University of Helsinki, Viikki Biocenter, Helsinki, Finland
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41
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Using cryoEM Reconstruction and Phase Extension to Determine Crystal Structure of Bacteriophage ϕ6 Major Capsid Protein. Protein J 2013; 32:635-40. [DOI: 10.1007/s10930-013-9526-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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