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Indelicato G, Cermelli P, Twarock R. A coarse-grained model of the expansion of the human rhinovirus 2 capsid reveals insights in genome release. J R Soc Interface 2019; 16:20190044. [PMID: 31409237 PMCID: PMC6731498 DOI: 10.1098/rsif.2019.0044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 07/11/2019] [Indexed: 12/02/2022] Open
Abstract
Human rhinoviruses are causative agents of the common cold. In order to release their RNA genome into the host during a viral infection, these small viruses must undergo conformational changes in their capsids, whose detailed mechanism is strictly related to the process of RNA extrusion, which has been only partially elucidated. We study here a mathematical model for the structural transition between the native particle of human rhinovirus type 2 and its expanded form, viewing the process as an energy cascade, i.e. a sequence of metastable states with decreasing energy connected by minimum energy paths. We explore several transition pathways and discuss their implications for the RNA exit process.
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Affiliation(s)
| | - Paolo Cermelli
- Department of Mathematics, University of Turin, Turin, Italy
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Abstract
Roger W. Hendrix was at the forefront of bacteriophage biology for nearly 50 years and was central to our understanding of both viral capsid assembly and phage genomic diversity and evolution. Roger's warm and gentle demeanor belied a razor-sharp mind and warmed him to numerous highly productive collaborations that amplified his scientific impact. Roger was always completely open with scientific ideas while at the same time quietly agitating with a stream of new ways of thinking about problems and nudging our communities to search for innovative solutions: a gentle but highly effective provocateur.
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Affiliation(s)
- Sherwood R Casjens
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Graham F Hatfull
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Cermelli P, Indelicato G, Zappa E. Minimum energy paths for conformational changes of viral capsids. Phys Rev E 2018; 96:012407. [PMID: 29347131 DOI: 10.1103/physreve.96.012407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Indexed: 11/07/2022]
Abstract
In this work we study conformational changes of viral capsids using techniques of large deviations theory for stochastic differential equations. The viral capsid is a model of a complex system in which many units-the proteins forming the capsomers-interact by weak forces to form a structure with exceptional mechanical resistance. The destabilization of such a structure is interesting both, per se, since it is related either to infection or maturation processes and because it yields insights into the stability of complex structures in which the constitutive elements interact by weak attractive forces. We focus here on a simplified model of a dodecahedral viral capsid and assume that the capsomers are rigid plaquettes with one degree of freedom each. We compute the most probable transition path from the closed capsid to the final configuration using minimum energy paths and discuss the stability of intermediate states.
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Affiliation(s)
- Paolo Cermelli
- Dipartimento di Matematica, Università di Torino, 10123 Torino, Italy
| | - Giuliana Indelicato
- Department of Mathematics and York Centre for Complex Systems Analysis, University of York, York YO10 5GE, United Kingdom and Dipartimento di Matematica, Università di Torino, 10123 Torino, Italy
| | - Emilio Zappa
- Courant Institute of Mathematical Sciences, New York University, New York, New York 10012, USA
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Flexible Connectors between Capsomer Subunits that Regulate Capsid Assembly. J Mol Biol 2017; 429:2474-2489. [PMID: 28705762 DOI: 10.1016/j.jmb.2017.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 06/25/2017] [Accepted: 07/06/2017] [Indexed: 01/28/2023]
Abstract
Viruses build icosahedral capsids of specific size and shape by regulating the spatial arrangement of the hexameric and pentameric protein capsomers in the growing shell during assembly. In the T=7 capsids of Escherichia coli bacteriophage HK97 and other phages, 60 capsomers are hexons, while the rest are pentons that are correctly positioned during assembly. Assembly of the HK97 capsid to the correct size and shape has been shown to depend on specific ionic contacts between capsomers. We now describe additional ionic interactions within capsomers that also regulate assembly. Each is between the long hairpin, the "E-loop," that extends from one subunit to the adjacent subunit within the same capsomer. Glutamate E153 on the E-loop and arginine R210 on the adjacent subunit's backbone alpha-helix form salt bridges in hexamers and pentamers. Mutations that disrupt these salt bridges were lethal for virus production, because the mutant proteins assembled into tubes or sheets instead of capsids. X-ray structures show that the E153-R210 links are flexible and maintained during maturation despite radical changes in capsomer shape. The E153-R210 links appear to form early in assembly to enable capsomers to make programmed changes in their shape during assembly. The links also prevent flattening of capsomers and premature maturation. Mutant phenotypes and modeling support an assembly model in which flexible E153-R210 links mediate capsomer shape changes that control where pentons are placed to create normal-sized capsids. The E-loop may be conserved in other systems in order to play similar roles in regulating assembly.
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Sharma S, Conover GM, Elliott JL, Der Perng M, Herrmann H, Quinlan RA. αB-crystallin is a sensor for assembly intermediates and for the subunit topology of desmin intermediate filaments. Cell Stress Chaperones 2017; 22:613-626. [PMID: 28470624 PMCID: PMC5465037 DOI: 10.1007/s12192-017-0788-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 03/07/2017] [Accepted: 03/16/2017] [Indexed: 12/04/2022] Open
Abstract
Mutations in the small heat shock protein chaperone CRYAB (αB-crystallin/HSPB5) and the intermediate filament protein desmin, phenocopy each other causing cardiomyopathies. Whilst the binding sites for desmin on CRYAB have been determined, desmin epitopes responsible for CRYAB binding and also the parameters that determine CRYAB binding to desmin filaments are unknown. Using a combination of co-sedimentation centrifugation, viscometric assays and electron microscopy of negatively stained filaments to analyse the in vitro assembly of desmin filaments, we show that the binding of CRYAB to desmin is subject to its assembly status, to the subunit organization within filaments formed and to the integrity of the C-terminal tail domain of desmin. Our in vitro studies using a rapid assembly protocol, C-terminally truncated desmin and two disease-causing mutants (I451M and R454W) suggest that CRYAB is a sensor for the surface topology of the desmin filament. Our data also suggest that CRYAB performs an assembly chaperone role because the assembling filaments have different CRYAB-binding properties during the maturation process. We suggest that the capability of CRYAB to distinguish between filaments with different surface topologies due either to mutation (R454W) or assembly protocol is important to understanding the pathomechanism(s) of desmin-CRYAB myopathies.
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Affiliation(s)
- Sarika Sharma
- Division of Molecular Genetics, German Cancer Research Center, Heidelberg, Germany
| | - Gloria M Conover
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
| | - Jayne L Elliott
- Department of Biosciences and the Biophysical Sciences Institute, University of Durham, Durham, UK
| | - Ming Der Perng
- Institute of Molecular Medicine, College of Life Sciences, National Tsing Hua University, Hsinchu, 300, Taiwan
| | - Harald Herrmann
- Division of Molecular Genetics, German Cancer Research Center, Heidelberg, Germany
- Institute of Neuropathology, University Hospital Erlangen, Erlangen, Germany
| | - Roy A Quinlan
- Department of Biosciences and the Biophysical Sciences Institute, University of Durham, Durham, UK.
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Marchetti M, Wuite GJL, Roos WH. Atomic force microscopy observation and characterization of single virions and virus-like particles by nano-indentation. Curr Opin Virol 2016; 18:82-8. [DOI: 10.1016/j.coviro.2016.05.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 05/10/2016] [Accepted: 05/12/2016] [Indexed: 11/15/2022]
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Konevtsova OV, Lorman VL, Rochal SB. Theory of morphological transformation of viral capsid shell during the maturation process in the HK97 bacteriophage and similar viruses. Phys Rev E 2016; 93:052412. [PMID: 27300929 DOI: 10.1103/physreve.93.052412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Indexed: 11/07/2022]
Abstract
We consider the symmetry and physical origin of collective displacement modes playing a crucial role in the morphological transformation during the maturation of the HK97 bacteriophage and similar viruses. It is shown that the experimentally observed hexamer deformation and pentamer twist in the HK97 procapsid correspond to the simplest irreducible shear strain mode of a spherical shell. We also show that the icosahedral faceting of the bacteriophage capsid shell is driven by the simplest irreducible radial displacement field. The shear field has the rotational icosahedral symmetry group I while the radial field has the full icosahedral symmetry I_{h}. This difference makes their actions independent. The radial field sign discriminates between the icosahedral and the dodecahedral shapes of the faceted capsid shell, thus making the approach relevant not only for the HK97-like viruses but also for the parvovirus family. In the frame of the Landau-Ginzburg formalism we propose a simple phenomenological model valid for the first reversible step of the HK97 maturation process. The calculated phase diagram illustrates the discontinuous character of the virus shape transformation. The characteristics of the virus shell faceting and expansion obtained in the in vitro and in vivo experiments are related to the decrease in the capsid shell thickness and to the increase of the internal capsid pressure.
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Affiliation(s)
- O V Konevtsova
- Faculty of Physics, Southern Federal University, 5 Zorge street, 344090 Rostov-on-Don, Russia
| | - V L Lorman
- Laboratoire Charles Coulomb, UMR 5221 CNRS and Université de Montpellier, place Eugène Bataillon, 34095 Montpellier, France
| | - S B Rochal
- Faculty of Physics, Southern Federal University, 5 Zorge street, 344090 Rostov-on-Don, Russia
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Suhanovsky MM, Teschke CM. Nature's favorite building block: Deciphering folding and capsid assembly of proteins with the HK97-fold. Virology 2015; 479-480:487-97. [PMID: 25864106 PMCID: PMC4424165 DOI: 10.1016/j.virol.2015.02.055] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 02/24/2015] [Accepted: 02/27/2015] [Indexed: 01/08/2023]
Abstract
For many (if not all) bacterial and archaeal tailed viruses and eukaryotic Herpesvirdae the HK97-fold serves as the major architectural element in icosahedral capsid formation while still enabling the conformational flexibility required during assembly and maturation. Auxiliary proteins or Δ-domains strictly control assembly of multiple, identical, HK97-like subunits into procapsids with specific icosahedral symmetries, rather than aberrant non-icosahedral structures. Procapsids are precursor structures that mature into capsids in a process involving release of auxiliary proteins (or cleavage of Δ-domains), dsDNA packaging, and conformational rearrangement of the HK97-like subunits. Some coat proteins built on the ubiquitous HK97-fold also have accessory domains or loops that impart specific functions, such as increased monomer, procapsid, or capsid stability. In this review, we analyze the numerous HK97-like coat protein structures that are emerging in the literature (over 40 at time of writing) by comparing their topology, additional domains, and their assembly and misassembly reactions.
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Affiliation(s)
- Margaret M Suhanovsky
- Department of Molecular and Cell Biology, University of Connecticut, 91N. Eagleville Rd. Storrs, CT 06269-3125, USA.
| | - Carolyn M Teschke
- Department of Molecular and Cell Biology, University of Connecticut, 91N. Eagleville Rd. Storrs, CT 06269-3125, USA; Department of Chemistry, University of Connecticut, 91N. Eagleville Rd. Storrs, CT 06269-3125, USA.
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Casjens SR, Hendrix RW. Bacteriophage lambda: Early pioneer and still relevant. Virology 2015; 479-480:310-30. [PMID: 25742714 PMCID: PMC4424060 DOI: 10.1016/j.virol.2015.02.010] [Citation(s) in RCA: 182] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/13/2015] [Accepted: 02/05/2015] [Indexed: 12/14/2022]
Abstract
Molecular genetic research on bacteriophage lambda carried out during its golden age from the mid-1950s to mid-1980s was critically important in the attainment of our current understanding of the sophisticated and complex mechanisms by which the expression of genes is controlled, of DNA virus assembly and of the molecular nature of lysogeny. The development of molecular cloning techniques, ironically instigated largely by phage lambda researchers, allowed many phage workers to switch their efforts to other biological systems. Nonetheless, since that time the ongoing study of lambda and its relatives has continued to give important new insights. In this review we give some relevant early history and describe recent developments in understanding the molecular biology of lambda's life cycle.
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Affiliation(s)
- Sherwood R Casjens
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Emma Eccles Jones Medical Research Building, 15 North Medical Drive East, Salt Lake City, UT 84112, USA; Biology Department, University of Utah, Salt Lake City, UT 84112, USA.
| | - Roger W Hendrix
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
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