1
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Upadhyay G, Kapri R, Chaudhuri A. Homopolymer and heteropolymer translocation through patterned pores under fluctuating forces. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2024; 47:23. [PMID: 38573533 DOI: 10.1140/epje/s10189-024-00417-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 03/18/2024] [Indexed: 04/05/2024]
Abstract
We investigate the translocation of a semiflexible polymer through extended patterned pores using Langevin dynamics simulations, specifically focusing on the influence of a time-dependent driving force. Our findings reveal that, akin to its flexible counterpart, a rigid chain-like molecule translocates faster when subjected to an oscillating force than a constant force of equivalent average magnitude. The enhanced translocation is strongly correlated with the stiffness of the polymer and the stickiness of the pores. The arrangement of the pores plays a pivotal role in translocation dynamics, deeply influenced by the interplay between polymer stiffness and pore-polymer interactions. For heterogeneous polymers with periodically varying stiffness, the oscillating force introduces significant variations in the translocation time distributions based on segment sizes and orientations. On the basis of these insights, we propose a sequencing approach that harnesses distinct pore surface properties that are capable of accurately predicting sequences in heteropolymers with diverse bending rigidities.
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Affiliation(s)
- Gokul Upadhyay
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, Knowledge City, S. A. S. Nagar, Manauli, 140306, India
| | - Rajeev Kapri
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, Knowledge City, S. A. S. Nagar, Manauli, 140306, India
| | - Abhishek Chaudhuri
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, Knowledge City, S. A. S. Nagar, Manauli, 140306, India.
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2
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Coshic K, Maffeo C, Winogradoff D, Aksimentiev A. The structure and physical properties of a packaged bacteriophage particle. Nature 2024; 627:905-914. [PMID: 38448589 DOI: 10.1038/s41586-024-07150-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 02/01/2024] [Indexed: 03/08/2024]
Abstract
A string of nucleotides confined within a protein capsid contains all the instructions necessary to make a functional virus particle, a virion. Although the structure of the protein capsid is known for many virus species1,2, the three-dimensional organization of viral genomes has mostly eluded experimental probes3,4. Here we report all-atom structural models of an HK97 virion5, including its entire 39,732 base pair genome, obtained through multiresolution simulations. Mimicking the action of a packaging motor6, the genome was gradually loaded into the capsid. The structure of the packaged capsid was then refined through simulations of increasing resolution, which produced a 26 million atom model of the complete virion, including water and ions confined within the capsid. DNA packaging occurs through a loop extrusion mechanism7 that produces globally different configurations of the packaged genome and gives each viral particle individual traits. Multiple microsecond-long all-atom simulations characterized the effect of the packaged genome on capsid structure, internal pressure, electrostatics and diffusion of water, ions and DNA, and revealed the structural imprints of the capsid onto the genome. Our approach can be generalized to obtain complete all-atom structural models of other virus species, thereby potentially revealing new drug targets at the genome-capsid interface.
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Affiliation(s)
- Kush Coshic
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Christopher Maffeo
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - David Winogradoff
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Aleksei Aksimentiev
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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3
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Chang R, Davydov A, Jaroenlak P, Budaitis B, Ekiert DC, Bhabha G, Prakash M. Energetics of the microsporidian polar tube invasion machinery. eLife 2024; 12:RP86638. [PMID: 38381133 PMCID: PMC10942582 DOI: 10.7554/elife.86638] [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] [Indexed: 02/22/2024] Open
Abstract
Microsporidia are eukaryotic, obligate intracellular parasites that infect a wide range of hosts, leading to health and economic burdens worldwide. Microsporidia use an unusual invasion organelle called the polar tube (PT), which is ejected from a dormant spore at ultra-fast speeds, to infect host cells. The mechanics of PT ejection are impressive. Anncaliia algerae microsporidia spores (3-4 μm in size) shoot out a 100-nm-wide PT at a speed of 300 μm/s, creating a shear rate of 3000 s-1. The infectious cargo, which contains two nuclei, is shot through this narrow tube for a distance of ∼60-140 μm (Jaroenlak et al, 2020) and into the host cell. Considering the large hydraulic resistance in an extremely thin tube and the low-Reynolds-number nature of the process, it is not known how microsporidia can achieve this ultrafast event. In this study, we use Serial Block-Face Scanning Electron Microscopy to capture 3-dimensional snapshots of A. algerae spores in different states of the PT ejection process. Grounded in these data, we propose a theoretical framework starting with a systematic exploration of possible topological connectivity amongst organelles, and assess the energy requirements of the resulting models. We perform PT firing experiments in media of varying viscosity, and use the results to rank our proposed hypotheses based on their predicted energy requirement. We also present a possible mechanism for cargo translocation, and quantitatively compare our predictions to experimental observations. Our study provides a comprehensive biophysical analysis of the energy dissipation of microsporidian infection process and demonstrates the extreme limits of cellular hydraulics.
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Affiliation(s)
- Ray Chang
- Department of Bioengineering, Stanford UniversityStanfordUnited States
| | - Ari Davydov
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Pattana Jaroenlak
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Breane Budaitis
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Damian C Ekiert
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
- Department of Microbiology, New York University School of MedicineNew YorkUnited States
| | - Gira Bhabha
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Manu Prakash
- Department of Bioengineering, Stanford UniversityStanfordUnited States
- Woods Institute for the Environment, Stanford UniversityStanfordUnited States
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4
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Valbuena A, Strobl K, Gil-Redondo JC, Valiente L, de Pablo PJ, Mateu MG. Single-Molecule Analysis of Genome Uncoating from Individual Human Rhinovirus Particles, and Modulation by Antiviral Drugs. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2304722. [PMID: 37806749 DOI: 10.1002/smll.202304722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 09/26/2023] [Indexed: 10/10/2023]
Abstract
Infection of humans by many viruses is typically initiated by the internalization of a single virion in each of a few susceptible cells. Thus, the outcome of the infection process may depend on stochastic single-molecule events. A crucial process for viral infection, and thus a target for developing antiviral drugs, is the uncoating of the viral genome. Here a force spectroscopy procedure using an atomic force microscope is implemented to study uncoating for individual human rhinovirus particles. Application of an increasing mechanical force on a virion led to a high force-induced structural transition that facilitated extrusion of the viral RNA molecule without loss of capsid integrity. Application of force to virions that h ad previously extruded the RNA, or to RNA-free capsids, led to a lower force-induced event associated with capsid disruption. The kinetic parameters are determined for each reaction. The high-force event is a stochastic process governed by a moderate free energy barrier (≈20 kcal mol-1 ), which results in a heterogeneous population of structurally weakened virions in which different fractions of the RNA molecule are externalized. The effects of antiviral compounds or capsid mutation on the kinetics of this reaction reveal a correlation between the reaction rate and virus infectivity.
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Affiliation(s)
- Alejandro Valbuena
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Klara Strobl
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Juan Carlos Gil-Redondo
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Luis Valiente
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Pedro J de Pablo
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049, Madrid, Spain
- Instituto de Física de la Materia Condensada (IFIMAC), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Mauricio G Mateu
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, 28049, Madrid, Spain
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5
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Dasgupta S, Thomas JA, Ray K. Mechanism of Viral DNA Packaging in Phage T4 Using Single-Molecule Fluorescence Approaches. Viruses 2024; 16:192. [PMID: 38399968 PMCID: PMC10893049 DOI: 10.3390/v16020192] [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: 12/29/2023] [Revised: 01/19/2024] [Accepted: 01/23/2024] [Indexed: 02/25/2024] Open
Abstract
In all tailed phages, the packaging of the double-stranded genome into the head by a terminase motor complex is an essential step in virion formation. Despite extensive research, there are still major gaps in the understanding of this highly dynamic process and the mechanisms responsible for DNA translocation. Over the last fifteen years, single-molecule fluorescence technologies have been applied to study viral nucleic acid packaging using the robust and flexible T4 in vitro packaging system in conjunction with genetic, biochemical, and structural analyses. In this review, we discuss the novel findings from these studies, including that the T4 genome was determined to be packaged as an elongated loop via the colocalization of dye-labeled DNA termini above the portal structure. Packaging efficiency of the TerL motor was shown to be inherently linked to substrate structure, with packaging stalling at DNA branches. The latter led to the design of multiple experiments whose results all support a proposed torsional compression translocation model to explain substrate packaging. Evidence of substrate compression was derived from FRET and/or smFRET measurements of stalled versus resolvase released dye-labeled Y-DNAs and other dye-labeled substrates relative to motor components. Additionally, active in vivo T4 TerS fluorescent fusion proteins facilitated the application of advanced super-resolution optical microscopy toward the visualization of the initiation of packaging. The formation of twin TerS ring complexes, each expected to be ~15 nm in diameter, supports a double protein ring-DNA synapsis model for the control of packaging initiation, a model that may help explain the variety of ring structures reported among pac site phages. The examination of the dynamics of the T4 packaging motor at the single-molecule level in these studies demonstrates the value of state-of-the-art fluorescent tools for future studies of complex viral replication mechanisms.
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Affiliation(s)
- Souradip Dasgupta
- Division of Vaccine Research, Institute of Human Virology, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201, USA
| | - Julie A. Thomas
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, NY 14623, USA;
| | - Krishanu Ray
- Division of Vaccine Research, Institute of Human Virology, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201, USA
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201, USA
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6
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Kiss B, Kellermayer M. Packing up the genome. eLife 2023; 12:e94128. [PMID: 38095555 PMCID: PMC10721213 DOI: 10.7554/elife.94128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023] Open
Abstract
Nucleotide and force-dependent mechanisms control how the viral genome of lambda bacteriophage is inserted into capsids.
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Affiliation(s)
- Bálint Kiss
- Department of Biophysics and Radiation Biology, Semmelweis UniversityBudapestHungary
| | - Miklós Kellermayer
- Department of Biophysics and Radiation Biology, Semmelweis UniversityBudapestHungary
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7
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Villanueva Valencia JR, Li D, Casjens SR, Evilevitch A. 'SAXS-osmometer' method provides measurement of DNA pressure in viral capsids and delivers an empirical equation of state. Nucleic Acids Res 2023; 51:11415-11427. [PMID: 37889048 PMCID: PMC10681747 DOI: 10.1093/nar/gkad852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 09/21/2023] [Accepted: 09/30/2023] [Indexed: 10/28/2023] Open
Abstract
We present a novel method that provides a measurement of DNA pressure in viral capsids using small angle X-ray scattering (SAXS). This method, unlike our previous assay, does not require triggering genome release with a viral receptor. Thus, it can be used to determine the existence of a pressurized genome state in a wide range of virus systems, even if the receptor is not known, leading to a better understanding of the processes of viral genome uncoating and encapsidation in the course of infection. Furthermore, by measuring DNA pressure for a collection of bacteriophages with varying DNA packing densities, we derived an empirical equation of state (EOS) that accurately predicts the relation between the capsid pressure and the packaged DNA density and includes the contribution of both DNA-DNA interaction energy and DNA bending stress to the total DNA pressure. We believe that our SAXS-osmometer method and the EOS, combined, provide the necessary tools to investigate physico-chemical properties of confined DNA condensates and mechanisms of infection, and may also provide essential data for the design of viral vectors in gene therapy applications and development of antivirals that target the pressurized genome state.
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Affiliation(s)
| | - Dong Li
- Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Sherwood R Casjens
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Alex Evilevitch
- Department of Experimental Medical Science and NanoLund, Lund University, Box 124, Lund, Sweden
- Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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8
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Villanueva Valencia JR, Tsimtsirakis E, Krueger S, Evilevitch A. Temperature-induced DNA density transition in phage λ capsid revealed with contrast-matching SANS. Proc Natl Acad Sci U S A 2023; 120:e2220518120. [PMID: 37903276 PMCID: PMC10636372 DOI: 10.1073/pnas.2220518120] [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: 12/04/2022] [Accepted: 09/25/2023] [Indexed: 11/01/2023] Open
Abstract
Structural details of a genome packaged in a viral capsid are essential for understanding how the structural arrangement of a viral genome in a capsid controls its release dynamics during infection, which critically affects viral replication. We previously found a temperature-induced, solid-like to fluid-like mechanical transition of packaged λ-genome that leads to rapid DNA ejection. However, an understanding of the structural origin of this transition was lacking. Here, we use small-angle neutron scattering (SANS) to reveal the scattering form factor of dsDNA packaged in phage λ capsid by contrast matching the scattering signal from the viral capsid with deuterated buffer. We used small-angle X-ray scattering and cryoelectron microscopy reconstructions to determine the initial structural input parameters for intracapsid DNA, which allows accurate modeling of our SANS data. As result, we show a temperature-dependent density transition of intracapsid DNA occurring between two coexisting phases-a hexagonally ordered high-density DNA phase in the capsid periphery and a low-density, less-ordered DNA phase in the core. As the temperature is increased from 20 °C to 40 °C, we found that the core-DNA phase undergoes a density and volume transition close to the physiological temperature of infection (~37 °C). The transition yields a lower energy state of DNA in the capsid core due to lower density and reduced packing defects. This increases DNA mobility, which is required to initiate rapid genome ejection from the virus capsid into a host cell, causing infection. These data reconcile our earlier findings of mechanical DNA transition in phage.
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Affiliation(s)
| | - Efthymios Tsimtsirakis
- Department of Experimental Medical Science and NanoLund, Lund University, Lund22184, Sweden
| | - Susan Krueger
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD20899-6102
| | - Alex Evilevitch
- Department of Experimental Medical Science and NanoLund, Lund University, Lund22184, Sweden
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9
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Chang R, Davydov A, Jaroenlak P, Budaitis B, Ekiert DC, Bhabha G, Prakash M. Energetics of the Microsporidian Polar Tube Invasion Machinery. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.17.524456. [PMID: 36711805 PMCID: PMC9884504 DOI: 10.1101/2023.01.17.524456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Microsporidia are eukaryotic, obligate intracellular parasites that infect a wide range of hosts, leading to health and economic burdens worldwide. Microsporidia use an unusual invasion organelle called the polar tube (PT), which is ejected from a dormant spore at ultra-fast speeds, to infect host cells. The mechanics of PT ejection are impressive. Anncaliia algerae microsporidia spores (3-4 μm in size) shoot out a 100-nm-wide PT at a speed of 300 μm/sec, creating a shear rate of 3000 sec-1. The infectious cargo, which contains two nuclei, is shot through this narrow tube for a distance of ~60-140 μm (Jaroenlak et al., 2020) and into the host cell. Considering the large hydraulic resistance in an extremely thin tube and the low-Reynolds-number nature of the process, it is not known how microsporidia can achieve this ultrafast event. In this study, we use Serial Block-Face Scanning Electron Microscopy to capture 3-dimensional snapshots of A. algerae spores in different states of the PT ejection process. Grounded in these data, we propose a theoretical framework starting with a systematic exploration of possible topological connectivity amongst organelles, and assess the energy requirements of the resulting models. We perform PT firing experiments in media of varying viscosity, and use the results to rank our proposed hypotheses based on their predicted energy requirement. We also present a possible mechanism for cargo translocation, and quantitatively compare our predictions to experimental observations. Our study provides a comprehensive biophysical analysis of the energy dissipation of microsporidian infection process and demonstrates the extreme limits of cellular hydraulics.
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Affiliation(s)
- Ray Chang
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
| | - Ari Davydov
- Department of Cell Biology, New York University School of Medicine, New York, New York, United States of America
| | - Pattana Jaroenlak
- Department of Cell Biology, New York University School of Medicine, New York, New York, United States of America
| | - Breane Budaitis
- Department of Cell Biology, New York University School of Medicine, New York, New York, United States of America
| | - Damian C. Ekiert
- Department of Cell Biology, New York University School of Medicine, New York, New York, United States of America
- Department of Microbiology, New York University School of Medicine, New York, New York, United States of America
| | - Gira Bhabha
- Department of Cell Biology, New York University School of Medicine, New York, New York, United States of America
| | - Manu Prakash
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
- Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
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10
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Fizari M, Keller N, Jardine PJ, Smith DE. Role of DNA-DNA sliding friction and nonequilibrium dynamics in viral genome ejection and packaging. Nucleic Acids Res 2023; 51:8060-8069. [PMID: 37449417 PMCID: PMC10450192 DOI: 10.1093/nar/gkad582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/17/2023] [Accepted: 06/27/2023] [Indexed: 07/18/2023] Open
Abstract
Many viruses eject their DNA via a nanochannel in the viral shell, driven by internal forces arising from the high-density genome packing. The speed of DNA exit is controlled by friction forces that limit the molecular mobility, but the nature of this friction is unknown. We introduce a method to probe the mobility of the tightly confined DNA by measuring DNA exit from phage phi29 capsids with optical tweezers. We measure extremely low initial exit velocity, a regime of exponentially increasing velocity, stochastic pausing that dominates the kinetics and large dynamic heterogeneity. Measurements with variable applied force provide evidence that the initial velocity is controlled by DNA-DNA sliding friction, consistent with a Frenkel-Kontorova model for nanoscale friction. We confirm several aspects of the ejection dynamics predicted by theoretical models. Features of the pausing suggest that it is connected to the phenomenon of 'clogging' in soft matter systems. Our results provide evidence that DNA-DNA friction and clogging control the DNA exit dynamics, but that this friction does not significantly affect DNA packaging.
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Affiliation(s)
- Mounir Fizari
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Nicholas Keller
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Paul J Jardine
- Department of Diagnostic and Biological Sciences and Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Douglas E Smith
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA
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11
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Lin YY, Brouns T, Kolbeck PJ, Vanderlinden W, Lipfert J. High-yield ligation-free assembly of DNA constructs with nucleosome positioning sequence repeats for single-molecule manipulation assays. J Biol Chem 2023; 299:104874. [PMID: 37257819 PMCID: PMC10404619 DOI: 10.1016/j.jbc.2023.104874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/08/2023] [Accepted: 05/16/2023] [Indexed: 06/02/2023] Open
Abstract
Force and torque spectroscopy have provided unprecedented insights into the mechanical properties, conformational transitions, and dynamics of DNA and DNA-protein complexes, notably nucleosomes. Reliable single-molecule manipulation measurements require, however, specific and stable attachment chemistries to tether the molecules of interest. Here, we present a functionalization strategy for DNA that enables high-yield production of constructs for torsionally constrained and very stable attachment. The method is based on two subsequent PCRs: first ∼380 bp long DNA strands are generated that contain multiple labels, which are used as "megaprimers" in a second PCR to generate ∼kbp long double-stranded DNA constructs with multiple labels at the respective ends. To achieve high-force stability, we use dibenzocyclooctyne-based click chemistry for covalent attachment to the surface and biotin-streptavidin coupling to the bead. The resulting tethers are torsionally constrained and extremely stable under load, with an average lifetime of 70 ± 3 h at 45 pN. The high yield of the approach enables nucleosome reconstitution by salt dialysis on the functionalized DNA, and we demonstrate proof-of-concept measurements on nucleosome assembly statistics and inner turn unwrapping under force. We anticipate that our approach will facilitate a range of studies of DNA interactions and nucleoprotein complexes under forces and torques.
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Affiliation(s)
- Yi-Yun Lin
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Munich, Germany; Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands
| | - Tine Brouns
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Munich, Germany; Division of Molecular Imaging and Photonics, KU Leuven, Leuven, Belgium
| | - Pauline J Kolbeck
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Munich, Germany; Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands
| | - Willem Vanderlinden
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Munich, Germany; Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands.
| | - Jan Lipfert
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Munich, Germany; Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands.
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12
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Bohmer M, Bhullar AS, Weitao T, Zhang L, Lee JH, Guo P. Revolving hexameric ATPases as asymmetric motors to translocate double-stranded DNA genome along one strand. iScience 2023; 26:106922. [PMID: 37305704 PMCID: PMC10250835 DOI: 10.1016/j.isci.2023.106922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023] Open
Abstract
DsDNA translocation through nanoscale pores is generally accomplished by ATPase biomotors. The discovery of the revolving dsDNA translocation mechanism, as opposed to rotation, in bacteriophage phi29 elucidated how ATPase motors move dsDNA. Revolution-driven, hexameric dsDNA motors have been reported in herpesvirus, bacterial FtsK, Streptomyces TraB, and T7 phage. This review explores the common relationship between their structure and mechanisms. Commonalities include moving along the 5'→3' strand, inchworm sequential action leading to an asymmetrical structure, channel chirality, channel size, and 3-step channel gating for controlling motion direction. The revolving mechanism and contact with one of the dsDNA strands addresses the historic controversy of dsDNA packaging using nicked, gapped, hybrid, or chemically modified DNA. These controversies surrounding dsDNA packaging activity using modified materials can be answered by whether the modification was introduced into the 3'→5' or 5'→3' strand. Perspectives concerning solutions to the controversy of motor structure and stoichiometry are also discussed.
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Affiliation(s)
- Margaret Bohmer
- Center for RNA Nanobiotechnology and Nanomedicine, The Ohio State University, Columbus, OH, USA
- College of Pharmacy, Division of Pharmaceutics and Pharmacology, The Ohio State University, Columbus, OH, USA
- College of Medicine, Dorothy M. Davis Heart and Lung Research Institute and James Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Abhjeet S. Bhullar
- Center for RNA Nanobiotechnology and Nanomedicine, The Ohio State University, Columbus, OH, USA
- College of Pharmacy, Division of Pharmaceutics and Pharmacology, The Ohio State University, Columbus, OH, USA
- College of Medicine, Dorothy M. Davis Heart and Lung Research Institute and James Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
- Interdisciplinary Biophysics Graduate Program, College of Art and Science, The Ohio State University, Columbus, OH 43210, USA
| | - Tao Weitao
- Center for the Genetics of Host Defense UT Southwestern Medical Center, Dallas, TX, USA
| | - Long Zhang
- Center for RNA Nanobiotechnology and Nanomedicine, The Ohio State University, Columbus, OH, USA
- College of Pharmacy, Division of Pharmaceutics and Pharmacology, The Ohio State University, Columbus, OH, USA
- College of Medicine, Dorothy M. Davis Heart and Lung Research Institute and James Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Jing-Huei Lee
- Department of Biomedical Engineering, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, OH, USA
| | - Peixuan Guo
- Center for RNA Nanobiotechnology and Nanomedicine, The Ohio State University, Columbus, OH, USA
- College of Pharmacy, Division of Pharmaceutics and Pharmacology, The Ohio State University, Columbus, OH, USA
- College of Medicine, Dorothy M. Davis Heart and Lung Research Institute and James Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
- Interdisciplinary Biophysics Graduate Program, College of Art and Science, The Ohio State University, Columbus, OH 43210, USA
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13
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Bayfield OW, Shkoporov AN, Yutin N, Khokhlova EV, Smith JLR, Hawkins DEDP, Koonin EV, Hill C, Antson AA. Structural atlas of a human gut crassvirus. Nature 2023; 617:409-416. [PMID: 37138077 PMCID: PMC10172136 DOI: 10.1038/s41586-023-06019-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 03/27/2023] [Indexed: 05/05/2023]
Abstract
CrAssphage and related viruses of the order Crassvirales (hereafter referred to as crassviruses) were originally discovered by cross-assembly of metagenomic sequences. They are the most abundant viruses in the human gut, are found in the majority of individual gut viromes, and account for up to 95% of the viral sequences in some individuals1-4. Crassviruses are likely to have major roles in shaping the composition and functionality of the human microbiome, but the structures and roles of most of the virally encoded proteins are unknown, with only generic predictions resulting from bioinformatic analyses4,5. Here we present a cryo-electron microscopy reconstruction of Bacteroides intestinalis virus ΦcrAss0016, providing the structural basis for the functional assignment of most of its virion proteins. The muzzle protein forms an assembly about 1 MDa in size at the end of the tail and exhibits a previously unknown fold that we designate the 'crass fold', that is likely to serve as a gatekeeper that controls the ejection of cargos. In addition to packing the approximately 103 kb of virus DNA, the ΦcrAss001 virion has extensive storage space for virally encoded cargo proteins in the capsid and, unusually, within the tail. One of the cargo proteins is present in both the capsid and the tail, suggesting a general mechanism for protein ejection, which involves partial unfolding of proteins during their extrusion through the tail. These findings provide a structural basis for understanding the mechanisms of assembly and infection of these highly abundant crassviruses.
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Affiliation(s)
- Oliver W Bayfield
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, UK.
| | - Andrey N Shkoporov
- APC Microbiome Ireland and School of Microbiology, University College Cork, Cork, Ireland
| | - Natalya Yutin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Ekaterina V Khokhlova
- APC Microbiome Ireland and School of Microbiology, University College Cork, Cork, Ireland
| | - Jake L R Smith
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, UK
| | - Dorothy E D P Hawkins
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, UK
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Colin Hill
- APC Microbiome Ireland and School of Microbiology, University College Cork, Cork, Ireland
| | - Alfred A Antson
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, UK.
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14
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Guerra A, Slim AC, Holmes DP, Kodio O. Self-Ordering of Buckling, Bending, and Bumping Beams. PHYSICAL REVIEW LETTERS 2023; 130:148201. [PMID: 37084420 DOI: 10.1103/physrevlett.130.148201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 02/07/2023] [Indexed: 05/03/2023]
Abstract
A collection of thin structures buckle, bend, and bump into each other when confined. This contact can lead to the formation of patterns: hair will self-organize in curls; DNA strands will layer into cell nuclei; paper, when crumpled, will fold in on itself, forming a maze of interleaved sheets. This pattern formation changes how densely the structures can pack, as well as the mechanical properties of the system. How and when these patterns form, as well as the force required to pack these structures is not currently understood. Here we study the emergence of order in a canonical example of packing in slender structures, i.e., a system of parallel confined elastic beams. Using tabletop experiments, simulations, and standard theory from statistical mechanics, we predict the amount of confinement (growth or compression) of the beams that will guarantee a global system order, which depends only on the initial geometry of the system. Furthermore, we find that the compressive stiffness and stored bending energy of this metamaterial are directly proportional to the number of beams that are geometrically frustrated at any given point. We expect these results to elucidate the mechanisms leading to pattern formation in these kinds of systems and to provide a new mechanical metamaterial, with a tunable resistance to compressive force.
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Affiliation(s)
- Arman Guerra
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215, USA
| | - Anja C Slim
- School of Mathematics, Monash University, Clayton Victoria 3800, Australia
- School of Earth, Atmosphere and Environment, Monash University, Clayton Victoria 3800, Australia
| | - Douglas P Holmes
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215, USA
| | - Ousmane Kodio
- Department of Mathematics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Mechanical Engineering, University of California, Santa Barbara, California 93106, USA
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15
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Fizari M, Keller N, Jardine PJ, Smith DE. Role of DNA-DNA sliding friction and non-equilibrium dynamics in viral genome ejection and packaging. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.03.535472. [PMID: 37066220 PMCID: PMC10104077 DOI: 10.1101/2023.04.03.535472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Many viruses eject their DNA via a nanochannel in the viral shell, driven by internal forces arising from the high-density genome packing. The speed of DNA exit is controlled by friction forces that limit the molecular mobility, but the nature of this friction is unknown. We introduce a method to probe the mobility of the tightly confined DNA by measuring DNA exit from phage phi29 capsids with optical tweezers. We measure extremely low initial exit velocity, a regime of exponentially increasing velocity, stochastic pausing that dominates the kinetics, and large dynamic heterogeneity. Measurements with variable applied force provide evidence that the initial velocity is controlled by DNA-DNA sliding friction, consistent with a Frenkel-Kontorova model for nanoscale friction. We confirm several aspects of the ejection dynamics predicted by theoretical models. Features of the pausing suggest it is connected to the phenomenon of "clogging" in soft-matter systems. Our results provide evidence that DNA-DNA friction and clogging control the DNA exit dynamics, but that this friction does not significantly affect DNA packaging.
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16
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Radiom M, Keys T, Turgay Y, Ali A, Preet S, Chesnov S, Lutz-Bueno V, Slack E, Mezzenga R. Mechanical tuning of virus-like particles. J Colloid Interface Sci 2023; 634:963-971. [PMID: 36571858 DOI: 10.1016/j.jcis.2022.12.090] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 12/18/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022]
Abstract
HYPOTHESIS Virus-like particles (VLPs) are promising scaffolds for developing mucosal vaccines. For their optimal performance, in addition to design parameters from an immunological perspective, biophysical properties may need to be considered. EXPERIMENTS We investigated the mechanical properties of VLPs scaffolded on the coat protein of Acinetobacter phage AP205 using atomic force microscopy and small angle X-ray scattering. FINDINGS Investigations showed that AP205 VLP is a tough nanoshell of stiffness 93 ± 23 pN/nm and elastic modulus 0.11 GPa. However, its mechanical properties are modulated by attaching muco-inert polyethylene glycol to 46 ± 10 pN/nm and 0.05 GPa. Addition of antigenic peptides derived from SARS-CoV2 spike protein by genetic fusion increased the stiffness to 146 ± 54 pN/nm although the elastic modulus remained unchanged. These results, which are interpreted in terms of shell thickness and coat protein net charge variations, demonstrate that surface conjugation can induce appreciable changes in the biophysical properties of VLP-scaffolded vaccines.
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Affiliation(s)
- Milad Radiom
- Laboratory of Food Immunology, Institute of Food, Nutrition and Health, ETH Zürich, Zürich, Switzerland; Laboratory of Food and Soft Materials, Institute of Food, Nutrition and Health, ETH Zürich, Zürich, Switzerland.
| | - Tim Keys
- Laboratory of Food Immunology, Institute of Food, Nutrition and Health, ETH Zürich, Zürich, Switzerland
| | - Yagmur Turgay
- Laboratory of Food Immunology, Institute of Food, Nutrition and Health, ETH Zürich, Zürich, Switzerland
| | - Ahmed Ali
- Laboratory of Food Immunology, Institute of Food, Nutrition and Health, ETH Zürich, Zürich, Switzerland
| | - Swapan Preet
- Laboratory of Food Immunology, Institute of Food, Nutrition and Health, ETH Zürich, Zürich, Switzerland
| | - Serge Chesnov
- University of Zürich/ETH Zürich, Functional Genomics Centre Zürich, Zürich, Switzerland
| | | | - Emma Slack
- Laboratory of Food Immunology, Institute of Food, Nutrition and Health, ETH Zürich, Zürich, Switzerland.
| | - Raffaele Mezzenga
- Laboratory of Food and Soft Materials, Institute of Food, Nutrition and Health, ETH Zürich, Zürich, Switzerland.
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17
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Sun M, Liu M, Shan H, Li K, Wang P, Guo H, Zhao Y, Wang R, Tao Y, Yang L, Zhang Y, Su X, Liu Y, Li C, Lin J, Chen XL, Zhang YZ, Shen QT. Ring-stacked capsids of white spot syndrome virus and structural transitions with genome ejection. SCIENCE ADVANCES 2023; 9:eadd2796. [PMID: 36812312 PMCID: PMC9946344 DOI: 10.1126/sciadv.add2796] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
White spot syndrome virus (WSSV) is one of the largest DNA viruses and the major pathogen responsible for white spot syndrome in crustaceans. The WSSV capsid is critical for genome encapsulation and ejection and exhibits the rod-shaped and oval-shaped structures during the viral life cycle. However, the detailed architecture of the capsid and the structural transition mechanism remain unclear. Here, using cryo-electron microscopy (cryo-EM), we obtained a cryo-EM model of the rod-shaped WSSV capsid and were able to characterize its ring-stacked assembly mechanism. Furthermore, we identified an oval-shaped WSSV capsid from intact WSSV virions and analyzed the structural transition mechanism from the oval-shaped to rod-shaped capsids induced by high salinity. These transitions, which decrease internal capsid pressure, always accompany DNA release and mostly eliminate the infection of the host cells. Our results demonstrate an unusual assembly mechanism of the WSSV capsid and offer structural insights into the pressure-driven genome release.
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Affiliation(s)
- Meiling Sun
- Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Mingdong Liu
- School of Life Science, Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- iHuman Institute and School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Hong Shan
- iHuman Institute and School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Kang Li
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao 266237, China
| | - Peng Wang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Huarong Guo
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
| | - Yaqi Zhao
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Rui Wang
- iHuman Institute and School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yiwen Tao
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Liuyan Yang
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao 266237, China
| | - Ying Zhang
- iHuman Institute and School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xiaoming Su
- High Performance Computing Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yunhui Liu
- School of Life Science, Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Chunyang Li
- Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - James Lin
- High Performance Computing Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiu-Lan Chen
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao 266237, China
| | - Yu-Zhong Zhang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao 266237, China
- Corresponding author. (Q.-T.S.); (Y.-Z.Z.)
| | - Qing-Tao Shen
- School of Life Science, Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- iHuman Institute and School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Corresponding author. (Q.-T.S.); (Y.-Z.Z.)
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18
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Pathak AK, Bandyopadhyay T. Heat-induced transitions of an empty minute virus of mice capsid in explicit water: all-atom MD simulation. J Biomol Struct Dyn 2022; 40:11900-11913. [PMID: 34459706 DOI: 10.1080/07391102.2021.1969283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The capsid-like structure of the virus-based protein nanoparticles (NPs) can serve as bionanomaterials, with applications in biomedicines and nanotechnology. Release of packaged material from these nanocontainers is associated with subtle conformational changes of the NP structure, which in vitro, is readily accomplished by heating. Characterizing the structural changes as a function of temperature may provide fresh insights into nanomaterial/antiviral strategies. Here, we have calculated heat induced changes in the properties of an empty minute virus of mice particle using large-scale ≈ 3.0 × 106 all-atom molecular dynamics simulations. We focus on two heat induced structural changes of the NP, namely, dynamical transition (DT) and breathing transition (BT), both characterized by sudden and sharp change of measured parameters at temperatures, TDT and TBT, respectively. While DT is assessed by mean-square fluctuation of hydrogen atoms of the NP, BT is monitored through internal volume and permeation rate of water molecules through the NP. Both the transitions, resulting primarily from collective atomistic motion, are found to occur at temperatures widely separated from one another (TBT>TDT). The breathing motions, responsible for the translocation events of the packaged materials through the NP to kick off, are further probed by computing atomic resolution stresses from NVE simulations. Distribution of equilibrium atomistic stresses on the NP reveals a largely asymmetric nature and suggests structural breathing may actually represent large dynamic changes in the hotspot regions, far from the NP pores, which is in remarkable resemblance with recently conducted hydrogen-deuterium exchange coupled to mass spectrometry experiment. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Arup Kumar Pathak
- Theoretical Chemistry Section, Chemistry Division, Bhabha Atomic Research Centre, Mumbai, India.,Homi Bhabha National Institute, Mumbai, India
| | - Tusar Bandyopadhyay
- Theoretical Chemistry Section, Chemistry Division, Bhabha Atomic Research Centre, Mumbai, India.,Homi Bhabha National Institute, Mumbai, India
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19
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Butala M, Dragoš A. Unique relationships between phages and endospore-forming hosts. Trends Microbiol 2022; 31:498-510. [PMID: 36535834 DOI: 10.1016/j.tim.2022.11.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 11/23/2022] [Accepted: 11/23/2022] [Indexed: 12/23/2022]
Abstract
As part of their survival strategy under harsh environmental conditions, endospore-forming bacteria can trigger a sporulation developmental program. Although the regulatory cascades that precisely control the transformation of vegetative bacteria into mother cells and resilient spores have been described in detail, less is known about how bacteriophages that prey on endospore-formers exploit sporulation. Herein, we argue that phages infecting these bacteria have evolved several specific molecular mechanisms, not yet known in other bacteria, that manifest from the phage-driven alliance to negative effects on the host. We anticipate that the relationships between phages and endospore-formers outlined here will inspire studies on phage ecology and evolution, and could facilitate important advances in the development of phage therapies against pathogenic spore-formers.
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Affiliation(s)
- Matej Butala
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Anna Dragoš
- Department of Microbiology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia.
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20
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CryoEM structure and assembly mechanism of a bacterial virus genome gatekeeper. Nat Commun 2022; 13:7283. [PMID: 36435855 PMCID: PMC9701221 DOI: 10.1038/s41467-022-34999-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 11/15/2022] [Indexed: 11/28/2022] Open
Abstract
Numerous viruses package their dsDNA genome into preformed capsids through a portal gatekeeper that is subsequently closed. We report the structure of the DNA gatekeeper complex of bacteriophage SPP1 (gp612gp1512gp166) in the post-DNA packaging state at 2.7 Å resolution obtained by single particle cryo-electron microscopy. Comparison of the native SPP1 complex with assembly-naïve structures of individual components uncovered the complex program of conformational changes leading to its assembly. After DNA packaging, gp15 binds via its C-terminus to the gp6 oligomer positioning gp15 subunits for oligomerization. Gp15 refolds its inner loops creating an intersubunit β-barrel that establishes different types of contacts with six gp16 subunits. Gp16 binding and oligomerization is accompanied by folding of helices that close the portal channel to keep the viral genome inside the capsid. This mechanism of assembly has broad functional and evolutionary implications for viruses of the prokaryotic tailed viruses-herpesviruses lineage.
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21
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Lokareddy RK, Hou CFD, Li F, Yang R, Cingolani G. Viral Small Terminase: A Divergent Structural Framework for a Conserved Biological Function. Viruses 2022; 14:v14102215. [PMID: 36298770 PMCID: PMC9611059 DOI: 10.3390/v14102215] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/03/2022] [Accepted: 10/05/2022] [Indexed: 11/07/2022] Open
Abstract
The genome packaging motor of bacteriophages and herpesviruses is built by two terminase subunits, known as large (TerL) and small (TerS), both essential for viral genome packaging. TerL structure, composition, and assembly to an empty capsid, as well as the mechanisms of ATP-dependent DNA packaging, have been studied in depth, shedding light on the chemo-mechanical coupling between ATP hydrolysis and DNA translocation. Instead, significantly less is known about the small terminase subunit, TerS, which is dispensable or even inhibitory in vitro, but essential in vivo. By taking advantage of the recent revolution in cryo-electron microscopy (cryo-EM) and building upon a wealth of crystallographic structures of phage TerSs, in this review, we take an inventory of known TerSs studied to date. Our analysis suggests that TerS evolved and diversified into a flexible molecular framework that can conserve biological function with minimal sequence and quaternary structure conservation to fit different packaging strategies and environmental conditions.
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22
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Fang Q, Tang WC, Fokine A, Mahalingam M, Shao Q, Rossmann MG, Rao VB. Structures of a large prolate virus capsid in unexpanded and expanded states generate insights into the icosahedral virus assembly. Proc Natl Acad Sci U S A 2022; 119:e2203272119. [PMID: 36161892 PMCID: PMC9546572 DOI: 10.1073/pnas.2203272119] [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: 02/27/2022] [Accepted: 08/31/2022] [Indexed: 11/18/2022] Open
Abstract
Many icosahedral viruses assemble proteinaceous precursors called proheads or procapsids. Proheads are metastable structures that undergo a profound structural transition known as expansion that transforms an immature unexpanded head into a mature genome-packaging head. Bacteriophage T4 is a model virus, well studied genetically and biochemically, but its structure determination has been challenging because of its large size and unusually prolate-shaped, ∼1,200-Å-long and ∼860-Å-wide capsid. Here, we report the cryogenic electron microscopy (cryo-EM) structures of T4 capsid in both of its major conformational states: unexpanded at a resolution of 5.1 Å and expanded at a resolution of 3.4 Å. These are among the largest structures deposited in Protein Data Bank to date and provide insights into virus assembly, head length determination, and shell expansion. First, the structures illustrate major domain movements and ∼70% additional gain in inner capsid volume, an essential transformation to contain the entire viral genome. Second, intricate intracapsomer interactions involving a unique insertion domain dramatically change, allowing the capsid subunits to rotate and twist while the capsomers remain fastened at quasi-threefold axes. Third, high-affinity binding sites emerge for a capsid decoration protein that clamps adjacent capsomers, imparting extraordinary structural stability. Fourth, subtle conformational changes at capsomers' periphery modulate intercapsomer angles between capsomer planes that control capsid length. Finally, conformational changes were observed at the symmetry-mismatched portal vertex, which might be involved in triggering head expansion. These analyses illustrate how small changes in local capsid subunit interactions lead to profound shifts in viral capsid morphology, stability, and volume.
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Affiliation(s)
- Qianglin Fang
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907
- School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong 518107, China
| | - Wei-Chun Tang
- Bacteriophage Medical Research Center, Department of Biology, The Catholic University of America, Washington, DC 20064
| | - Andrei Fokine
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907
| | - Marthandan Mahalingam
- Bacteriophage Medical Research Center, Department of Biology, The Catholic University of America, Washington, DC 20064
| | - Qianqian Shao
- School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong 518107, China
| | - Michael G. Rossmann
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907
| | - Venigalla B. Rao
- Bacteriophage Medical Research Center, Department of Biology, The Catholic University of America, Washington, DC 20064
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23
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Fiasconaro A, Díez-Señorans G, Falo F. End-pulled polymer translocation through a many-body flexible pore. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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24
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Imaging the Infection Cycle of T7 at the Single Virion Level. Int J Mol Sci 2022; 23:ijms231911252. [PMID: 36232552 PMCID: PMC9569847 DOI: 10.3390/ijms231911252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/17/2022] [Accepted: 09/21/2022] [Indexed: 11/17/2022] Open
Abstract
T7 phages are E. coli-infecting viruses that find and invade their target with high specificity and efficiency. The exact molecular mechanisms of the T7 infection cycle are yet unclear. As the infection involves mechanical events, single-particle methods are to be employed to alleviate the problems of ensemble averaging. Here we used TIRF microscopy to uncover the spatial dynamics of the target recognition and binding by individual T7 phage particles. In the initial phase, T7 virions bound reversibly to the bacterial membrane via two-dimensional diffusive exploration. Stable bacteriophage anchoring was achieved by tail-fiber complex to receptor binding which could be observed in detail by atomic force microscopy (AFM) under aqueous buffer conditions. The six anchored fibers of a given T7 phage-displayed isotropic spatial orientation. The viral infection led to the onset of an irreversible structural program in the host which occurred in three distinct steps. First, bacterial cell surface roughness, as monitored by AFM, increased progressively. Second, membrane blebs formed on the minute time scale (average ~5 min) as observed by phase-contrast microscopy. Finally, the host cell was lysed in a violent and explosive process that was followed by the quick release and dispersion of the phage progeny. DNA ejection from T7 could be evoked in vitro by photothermal excitation, which revealed that genome release is mechanically controlled to prevent premature delivery of host-lysis genes. The single-particle approach employed here thus provided an unprecedented insight into the details of the complete viral cycle.
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25
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Pajak J, Arya G. Molecular dynamics of DNA translocation by FtsK. Nucleic Acids Res 2022; 50:8459-8470. [PMID: 35947697 PMCID: PMC9410874 DOI: 10.1093/nar/gkac668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 07/16/2022] [Accepted: 07/23/2022] [Indexed: 12/24/2022] Open
Abstract
The bacterial FtsK motor harvests energy from ATP to translocate double-stranded DNA during cell division. Here, we probe the molecular mechanisms underlying coordinated DNA translocation in FtsK by performing long timescale simulations of its hexameric assembly and individual subunits. From these simulations we predict signaling pathways that connect the ATPase active site to DNA-gripping residues, which allows the motor to coordinate its translocation activity with its ATPase activity. Additionally, we utilize well-tempered metadynamics simulations to compute free-energy landscapes that elucidate the extended-to-compact transition involved in force generation. We show that nucleotide binding promotes a compact conformation of a motor subunit, whereas the apo subunit is flexible. Together, our results support a mechanism whereby each ATP-bound subunit of the motor conforms to the helical pitch of DNA, and ATP hydrolysis/product release causes a subunit to lose grip of DNA. By ordinally engaging and disengaging with DNA, the FtsK motor unidirectionally translocates DNA.
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Affiliation(s)
- Joshua Pajak
- Dept. of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA
- Dept. of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Gaurav Arya
- Dept. of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA
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26
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Fung HKH, Grimes S, Huet A, Duda RL, Chechik M, Gault J, Robinson C, Hendrix R, Jardine P, Conway J, Baumann C, Antson A. Structural basis of DNA packaging by a ring-type ATPase from an archetypal viral system. Nucleic Acids Res 2022; 50:8719-8732. [PMID: 35947691 PMCID: PMC9410871 DOI: 10.1093/nar/gkac647] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 07/06/2022] [Accepted: 07/24/2022] [Indexed: 12/24/2022] Open
Abstract
Many essential cellular processes rely on substrate rotation or translocation by a multi-subunit, ring-type NTPase. A large number of double-stranded DNA viruses, including tailed bacteriophages and herpes viruses, use a homomeric ring ATPase to processively translocate viral genomic DNA into procapsids during assembly. Our current understanding of viral DNA packaging comes from three archetypal bacteriophage systems: cos, pac and phi29. Detailed mechanistic understanding exists for pac and phi29, but not for cos. Here, we reconstituted in vitro a cos packaging system based on bacteriophage HK97 and provided a detailed biochemical and structural description. We used a photobleaching-based, single-molecule assay to determine the stoichiometry of the DNA-translocating ATPase large terminase. Crystal structures of the large terminase and DNA-recruiting small terminase, a first for a biochemically defined cos system, reveal mechanistic similarities between cos and pac systems. At the same time, mutational and biochemical analyses indicate a new regulatory mechanism for ATPase multimerization and coordination in the HK97 system. This work therefore establishes a framework for studying the evolutionary relationships between ATP-dependent DNA translocation machineries in double-stranded DNA viruses.
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Affiliation(s)
- Herman K H Fung
- Department of Biology, University of York, York, YO10 5DD, UK
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, YO10 5DD, UK
| | - Shelley Grimes
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Alexis Huet
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Robert L Duda
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Maria Chechik
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, YO10 5DD, UK
| | - Joseph Gault
- Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Carol V Robinson
- Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Roger W Hendrix
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Paul J Jardine
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - James F Conway
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | | | - Alfred A Antson
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, YO10 5DD, UK
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The Development of Single Molecule Force Spectroscopy: From Polymer Biophysics to Molecular Machines. Q Rev Biophys 2022; 55:e9. [PMID: 35916314 DOI: 10.1017/s0033583522000087] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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28
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Wang C, Hu HX, Zhou YL, Zhao B, Luo MB. Translocation of a Self-propelled Polymer through a Narrow Pore. CHINESE JOURNAL OF POLYMER SCIENCE 2022. [DOI: 10.1007/s10118-022-2768-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Gautam D, Ahmed N, Rao VKP. Modelling the Effect of Geometry and Loading on Mechanical Response of SARS-CoV-2. BIONANOSCIENCE 2022; 12:867-876. [PMID: 35729972 PMCID: PMC9194348 DOI: 10.1007/s12668-022-00993-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/14/2022] [Indexed: 11/26/2022]
Abstract
In recent times, coronavirus (SARS-CoV-2) becomes a pandemic disease across the globe. This virus affects the severe acute respiratory system that causes a type of pneumonia, which results in an outbreak in Wuhan, China, and then in whole global countries. The virus possesses a complex structure and varied in composition along with its geometrical shape and size. Contributions of the lipid and protein components of a virus to the influenza viral envelope’s mechanical properties are still unknown. In this work, the virus is modeled like the SARS-CoV-2 and surrounded with spikes made up of S glycoproteins, and numerical analysis was made to predict its mechanical behavior while resting on the substrate. The static and viscoelastic response of the virus was carried out in a finite element (FE) commercial software Ansys. The impact of changing viral envelope thickness on SARS-CoV-2 and bald virus stiffness was investigated. The viscoelastic analysis shows the increase in the deformation and stress with an increase in the pressure. The static analysis predicts the lower stiffness for SARS-CoV-2 compared to bald virion and increases with the increase in the envelop thickness. This study is useful for analyzing the effect of geometry and mechanical properties on the mechanical response of SARS-CoV-2.
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Affiliation(s)
- Diplesh Gautam
- Department of Mechanical Engineering, BITS Pilani, Pilani, 333031 Rajasthan India
| | - Nizam Ahmed
- Department of Mechanical Engineering, BITS Pilani, Pilani, 333031 Rajasthan India
| | - Venkatesh KP Rao
- Department of Mechanical Engineering, BITS Pilani, Pilani, 333031 Rajasthan India
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Varikoti RA, Fonseka HYY, Kelly MS, Javidi A, Damre M, Mullen S, Nugent JL, Gonzales CM, Stan G, Dima RI. Exploring the Effect of Mechanical Anisotropy of Protein Structures in the Unfoldase Mechanism of AAA+ Molecular Machines. NANOMATERIALS 2022; 12:nano12111849. [PMID: 35683705 PMCID: PMC9182431 DOI: 10.3390/nano12111849] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 05/25/2022] [Accepted: 05/25/2022] [Indexed: 02/06/2023]
Abstract
Essential cellular processes of microtubule disassembly and protein degradation, which span lengths from tens of μm to nm, are mediated by specialized molecular machines with similar hexameric structure and function. Our molecular simulations at atomistic and coarse-grained scales show that both the microtubule-severing protein spastin and the caseinolytic protease ClpY, accomplish spectacular unfolding of their diverse substrates, a microtubule lattice and dihydrofolate reductase (DHFR), by taking advantage of mechanical anisotropy in these proteins. Unfolding of wild-type DHFR requires disruption of mechanically strong β-sheet interfaces near each terminal, which yields branched pathways associated with unzipping along soft directions and shearing along strong directions. By contrast, unfolding of circular permutant DHFR variants involves single pathways due to softer mechanical interfaces near terminals, but translocation hindrance can arise from mechanical resistance of partially unfolded intermediates stabilized by β-sheets. For spastin, optimal severing action initiated by pulling on a tubulin subunit is achieved through specific orientation of the machine versus the substrate (microtubule lattice). Moreover, changes in the strength of the interactions between spastin and a microtubule filament, which can be driven by the tubulin code, lead to drastically different outcomes for the integrity of the hexameric structure of the machine.
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Affiliation(s)
- Rohith Anand Varikoti
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA; (R.A.V.); (H.Y.Y.F.); (M.S.K.); (M.D.); (J.L.N.IV)
| | - Hewafonsekage Yasan Y. Fonseka
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA; (R.A.V.); (H.Y.Y.F.); (M.S.K.); (M.D.); (J.L.N.IV)
| | - Maria S. Kelly
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA; (R.A.V.); (H.Y.Y.F.); (M.S.K.); (M.D.); (J.L.N.IV)
| | - Alex Javidi
- Data Sciences, Janssen Research and Development, Spring House, PA 19477, USA;
| | - Mangesh Damre
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA; (R.A.V.); (H.Y.Y.F.); (M.S.K.); (M.D.); (J.L.N.IV)
| | - Sarah Mullen
- Department of Chemistry, The College of Wooster, Wooster, OH 44691, USA;
| | - Jimmie L. Nugent
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA; (R.A.V.); (H.Y.Y.F.); (M.S.K.); (M.D.); (J.L.N.IV)
| | | | - George Stan
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA; (R.A.V.); (H.Y.Y.F.); (M.S.K.); (M.D.); (J.L.N.IV)
- Correspondence: (G.S.); (R.I.D.)
| | - Ruxandra I. Dima
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA; (R.A.V.); (H.Y.Y.F.); (M.S.K.); (M.D.); (J.L.N.IV)
- Correspondence: (G.S.); (R.I.D.)
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Morgan A, Eastlund A, Fischer C, Jardine P. Kinetics of ATP/ADP Binding to the gp16 ATPase. Biophys J 2022; 121:1909-1918. [PMID: 35421388 DOI: 10.1016/j.bpj.2022.04.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/05/2021] [Accepted: 04/08/2022] [Indexed: 11/02/2022] Open
Abstract
The gp16 ATPase is the constituent subunit of the pentameric dsDNA (Double-stranded Deoxyribonucleic Acid) translocation motor of the B. subtilis Φ29 bacteriophage. Although recent single-molecule studies have provided tantalizing clues about the activity of this motor, the mechanism by which the gp16 subunits couple the energy obtained from the binding and hydrolysis of ATP to the mechanical work of dsDNA translocation remains unknown. To address this need, we have characterized the binding of fluorophore labeled ATP and ADP to monomeric gp16 using a stopped-flow fluorescence assay. These experiments show that the binding of ATP/ADP occurs through a single-step mechanism with corresponding affinities of (523.8 ± 247.3) nM for ATP and a lower limit of 30μM for ADP. When analyzed through the lens of changes in free energy of the system, this difference in binding affinities is reasonable for a cyclical process of binding, hydrolysis, and product release. In addition to answering questions about the activity of monomeric gp16, these results are also a necessary step in constructing a model for inter-subunit communication within the pentameric gp16 motor.
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Affiliation(s)
- Aaron Morgan
- Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045
| | - Allen Eastlund
- Department of Diagnostic and Biological Sciences, University of Minnesota
| | - Christopher Fischer
- Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045
| | - Paul Jardine
- Department of Diagnostic and Biological Sciences, University of Minnesota
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32
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Rousso I, Deshpande A. Applications of Atomic Force Microscopy in HIV-1 Research. Viruses 2022; 14:v14030648. [PMID: 35337055 PMCID: PMC8955997 DOI: 10.3390/v14030648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 12/10/2022] Open
Abstract
Obtaining an understanding of the mechanism underlying the interrelations between the structure and function of HIV-1 is of pivotal importance. In previous decades, this mechanism was addressed extensively in a variety of studies using conventional approaches. More recently, atomic force microscopy, which is a relatively new technique with unique capabilities, has been utilized to study HIV-1 biology. Atomic force microscopy can generate high-resolution images at the nanometer-scale and analyze the mechanical properties of individual HIV-1 virions, virus components (e.g., capsids), and infected live cells under near-physiological environments. This review describes the working principles and various imaging and analysis modes of atomic force microscopy, and elaborates on its distinctive contributions to HIV-1 research in areas such as mechanobiology and the physics of infection.
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33
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Wang H, Xiong W. Revealing the Molecular Physics of Lattice Self-Assembly by Vibrational Hyperspectral Imaging. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:3017-3031. [PMID: 35238562 DOI: 10.1021/acs.langmuir.1c03313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Lattice self-assemblies (LSAs), which mimic protein assemblies, were studied using a new nonlinear vibrational imaging technique called vibrational sum-frequency generation (VSFG) microscopy. This technique successfully mapped out the mesoscopic morphology, microscopic geometry, symmetry, and ultrafast dynamics of an LSA formed by β-cyclodextrin (β-CD) and sodium dodecyl sulfate (SDS). The spatial imaging also revealed correlations between these different physical properties. Such knowledge shed light on the functions and mechanical properties of LSAs. In this Feature Article, we briefly introduce the fundamental principles of the VSFG microscope and then discuss the in-depth molecular physics of the LSAs revealed by this imaging technique. The application of the VSFG microscope to the artificial LSAs also paved the way for an alternative approach to studying the structure-dynamic-function relationships of protein assemblies, which were essential for life and difficult to study because of their various and complicated interactions. We expect that the hyperspectral VSFG microscope could be broadly applied to many noncentrosymmetric soft materials.
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34
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Sherwood JD, Ghosal S. Packing a flexible fiber into a cavity. Phys Rev E 2022; 105:035002. [PMID: 35428064 DOI: 10.1103/physreve.105.035002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Accepted: 03/07/2022] [Indexed: 06/14/2023]
Abstract
The insertion of an elastic rod or fiber into a confining cavity is studied. Such an insertion is a feature of a variety of problems, including packing and unpacking of DNA in viral capsids and the insertion of catheters during surgery. We consider a simplified geometry in which the container is a smooth (frictionless) circular cylinder of radius a. The fiber is pushed through a hole in the curved surface of the cylinder and is then assumed to stay in a cross-sectional plane perpendicular to the cylinder axis. A solution is found for the fiber shape in which most of the fiber lies against the curved interior surface of the cylinder, apart from the final end section of the fiber, of length 2.0888a, which crosses the interior of the cylinder before ending at the opposite side, which it meets at an angle 1.15 rad to the normal. The force required to push the fiber into the cylinder is EI/2a^{2}, where E is the fiber's Young's modulus and I its cross-sectional moment of inertia. The shape of the final end section of the fiber is confirmed by experiment.
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Affiliation(s)
- J D Sherwood
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB3 0WA, United Kingdom
| | - S Ghosal
- Department of Mechanical Engineering and Engineering Sciences and Applied Mathematics, Northwestern University, Evanston, Illinois 60208, USA
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35
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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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36
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Halloy F, Biscans A, Bujold KE, Debacker A, Hill AC, Lacroix A, Luige O, Strömberg R, Sundstrom L, Vogel J, Ghidini A. Innovative developments and emerging technologies in RNA therapeutics. RNA Biol 2022; 19:313-332. [PMID: 35188077 PMCID: PMC8865321 DOI: 10.1080/15476286.2022.2027150] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
RNA-based therapeutics are emerging as a powerful platform for the treatment of multiple diseases. Currently, the two main categories of nucleic acid therapeutics, antisense oligonucleotides and small interfering RNAs (siRNAs), achieve their therapeutic effect through either gene silencing, splicing modulation or microRNA binding, giving rise to versatile options to target pathogenic gene expression patterns. Moreover, ongoing research seeks to expand the scope of RNA-based drugs to include more complex nucleic acid templates, such as messenger RNA, as exemplified by the first approved mRNA-based vaccine in 2020. The increasing number of approved sequences and ongoing clinical trials has attracted considerable interest in the chemical development of oligonucleotides and nucleic acids as drugs, especially since the FDA approval of the first siRNA drug in 2018. As a result, a variety of innovative approaches is emerging, highlighting the potential of RNA as one of the most prominent therapeutic tools in the drug design and development pipeline. This review seeks to provide a comprehensive summary of current efforts in academia and industry aimed at fully realizing the potential of RNA-based therapeutics. Towards this, we introduce established and emerging RNA-based technologies, with a focus on their potential as biosensors and therapeutics. We then describe their mechanisms of action and their application in different disease contexts, along with the strengths and limitations of each strategy. Since the nucleic acid toolbox is rapidly expanding, we also introduce RNA minimal architectures, RNA/protein cleavers and viral RNA as promising modalities for new therapeutics and discuss future directions for the field.
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Affiliation(s)
- François Halloy
- Department of Paediatrics, Medical Sciences Division, University of Oxford, Oxford, UK
| | - Annabelle Biscans
- Oligonucleotide Chemistry, Discovery Sciences, BioPharmaceuticals R&d, AstraZeneca, Gothenburg, Sweden
| | - Katherine E. Bujold
- Department of Chemistry & Chemical Biology, McMaster University, (Ontario), Canada
| | | | - Alyssa C. Hill
- Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, Eth Zürich, Zürich, Switzerland
| | - Aurélie Lacroix
- Sixfold Bioscience, Translation & Innovation Hub, London, UK
| | - Olivia Luige
- Department of Biosciences and Nutrition, Karolinska Institutet, Sweden
| | - Roger Strömberg
- Department of Biosciences and Nutrition, Karolinska Institutet, Sweden
| | - Linda Sundstrom
- Mechanistic and Structural Biology, Discovery Sciences, BioPharmaceuticals R&d, AstraZeneca, Gothenburg, Sweden
| | - Jörg Vogel
- Helmholtz Institute for RNA-based Infection Research (Hiri), Helmholtz Center for Infection Research (Hzi), Würzburg, Germany
- RNA Biology Group, Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Alice Ghidini
- Mechanistic and Structural Biology, Discovery Sciences, BioPharmaceuticals R&d, AstraZeneca, Gothenburg, Sweden
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Abstract
Single-molecule magnetic tweezers deliver magnetic force and torque to single target molecules, permitting the study of dynamic changes in biomolecular structures and their interactions. Because the magnetic tweezer setups can generate magnetic fields that vary slowly over tens of millimeters-far larger than the nanometer scale of the single molecule events being observed-this technique can maintain essentially constant force levels during biochemical experiments while generating a biologically meaningful force on the order of 1-100 pN. When using bead-tether constructs to pull on single molecules, smaller magnetic beads and shorter submicrometer tethers improve dynamic response times and measurement precision. In addition, employing high-speed cameras, stronger light sources, and a graphics programming unit permits true high-resolution single-molecule magnetic tweezers that can track nanometer changes in target molecules on a millisecond or even submillisecond time scale. The unique force-clamping capacity of the magnetic tweezer technique provides a way to conduct measurements under near-equilibrium conditions and directly map the energy landscapes underlying various molecular phenomena. High-resolution single-molecule magnetic tweezers can thus be used to monitor crucial conformational changes in single-protein molecules, including those involved in mechanotransduction and protein folding. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Hyun-Kyu Choi
- Wallace H. Coulter Department of Biomedical Engineering and Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Hyun Gyu Kim
- School of Biological Sciences and Institute for Molecular Biology and Genetics, Seoul National University, Seoul, South Korea;
| | - Min Ju Shon
- Department of Physics and School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science & Technology (POSTECH), Pohang, South Korea;
| | - Tae-Young Yoon
- School of Biological Sciences and Institute for Molecular Biology and Genetics, Seoul National University, Seoul, South Korea;
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38
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Tall tails: cryo-electron microscopy of phage tail DNA ejection conduits. Biochem Soc Trans 2022; 50:459-22W. [PMID: 35129586 PMCID: PMC9022992 DOI: 10.1042/bst20210799] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 01/06/2022] [Accepted: 01/12/2022] [Indexed: 11/17/2022]
Abstract
The majority of phages, viruses that infect prokaryotes, inject their genomic material into their host through a tubular assembly known as a tail. Despite the genomic diversity of tailed phages, only three morphological archetypes have been described: contractile tails of Myoviridae-like phages; short non-contractile tails of Podoviridae-like phages; and long and flexible non-contractile tails of Siphoviridae-like phages. While early cryo-electron microscopy (cryo-EM) work elucidated the organisation of the syringe-like injection mechanism of contractile tails, the intrinsic flexibility of the long non-contractile tails prevented high-resolution structural determination. In 2020, four cryo-EM structures of Siphoviridae-like tail tubes were solved and revealed common themes and divergences. The central tube is structurally conserved and homologous to the hexameric rings of the tail tube protein (TTP) also found in contractile tails, bacterial pyocins, and type VI secretion systems. The interior surface of the tube presents analogous motifs of negatively charged amino acids proposed to facilitate ratcheting of the DNA during genome ejection. The lack of a conformational change upon genome ejection implicates the tape measure protein in triggering genome release. A distinctive feature of Siphoviridae-like tails is their flexibility. This results from loose inter-ring connections that can asymmetrically stretch on one side to allow bending and flexing of the tube without breaking. The outer surface of the tube differs greatly and may be smooth or rugged due to additional Ig-like domains in TTP. Some of these variable domains may contribute to adsorption of the phage to prokaryotic and eukaryotic cell surfaces affecting tropism and virulence.
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Murray LE, Kim H, Rice LM, Asbury CL. Catching the Conformational Wave: Measuring the Working Strokes of Protofilaments as They Curl Outward from Disassembling Microtubule Tips. Methods Mol Biol 2022; 2478:653-676. [PMID: 36063337 PMCID: PMC9542027 DOI: 10.1007/978-1-0716-2229-2_23] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Optical traps have enabled foundational studies of how mechanoenzymes such as kinesins and dynein motors walk along microtubules, how myosins move along F-actin, and how nucleic acid enzymes move along DNA or RNA. Often the filamentous substrates serve merely as passive tracks for mechanoenzymes but microtubules and F-actin are themselves dynamic protein polymers, capable of generating movement and force independently of conventional motors. Microtubule-driven forces are particularly important during mitosis, when they align duplicated chromosomes at the metaphase plate and then pull them apart during anaphase. These vital movements depend on specialized protein assemblies called kinetochores that couple the chromosomes to the tips of dynamic microtubule filaments, thereby allowing filament shortening to produce pulling forces. Although great strides have been made toward understanding the structures and functions of many kinetochore subcomplexes, the biophysical basis for their coupling to microtubule tips remains unclear. During tip disassembly, strain energy is released when straight protofilaments in the microtubule lattice curl outward, creating a conformational wave that propagates down the microtubule. A popular viewpoint is that the protofilaments as they curl outward hook elements of the kinetochore and tug on them, transferring some of their curvature strain energy to the kinetochore. As a first step toward testing this idea, we recently developed a laser trap assay to directly measure the working strokes generated by curling protofilaments. Our "wave" assay is based on an earlier pioneering study, with improvements that allow measurement of curl-driven movements as functions of force and quantification of their conformational strain energy. In this chapter, we provide a detailed protocol for our assay and describe briefly our instrument setup and data analysis methods.
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Affiliation(s)
- Lucas E. Murray
- Department of Physiology & Biophysics, University of Washington, Seattle WA 98195, USA
| | - Haein Kim
- Department of Physiology & Biophysics, University of Washington, Seattle WA 98195, USA
| | - Luke M. Rice
- Department of Biophysics, UT Southwestern Medical Center, Dallas TX 75390, USA
| | - Charles L. Asbury
- Department of Physiology & Biophysics, University of Washington, Seattle WA 98195, USA.,address correspondence to:
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40
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Aicart-Ramos C, Hormeno S, Wilkinson OJ, Dillingham MS, Moreno-Herrero F. Long DNA constructs to study helicases and nucleic acid translocases using optical tweezers. Methods Enzymol 2022; 673:311-358. [DOI: 10.1016/bs.mie.2022.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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41
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Knobler CM, Gelbart WM. How and why RNA genomes are (partially) ordered in viral capsids. Curr Opin Virol 2021; 52:203-210. [PMID: 34959081 DOI: 10.1016/j.coviro.2021.11.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 11/25/2021] [Indexed: 11/26/2022]
Abstract
There is a long and productive progression of X-ray crystallographic and electron microscopy studies establishing the structures of the spherical/icosahedral and cylindrical/helical capsids of a wide range of virus particles. This is because of the high degree of order - down to the Angstrom scale - in the secondary/tertiary/quaternary structure of the proteins making up the capsids. In stark contradistinction, very little is known about the structure of DNA or RNA genomes inside these capsids. This is because of the relatively large extent of disorder in the confined DNA or RNA, due to several fundamental reasons: topological defects in the DNA case, and secondary/tertiary structural disorder in the RNA case. In this article we discuss the range of partial order associated with the encapsidated genomes of single-stranded RNA viruses, focusing on the contrast between mono-partite and multi-partite viruses and on the effects of sequence-specific and non-specific interactions between RNA and capsid proteins.
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Affiliation(s)
- Charles M Knobler
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA 90095, United States
| | - William M Gelbart
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA 90095, United States; Molecular Biology Institute, UCLA, United States; California NanoSystems Institute, UCLA, United States.
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A viral genome packaging ring-ATPase is a flexibly coordinated pentamer. Nat Commun 2021; 12:6548. [PMID: 34772936 PMCID: PMC8589836 DOI: 10.1038/s41467-021-26800-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 10/21/2021] [Indexed: 01/13/2023] Open
Abstract
Multi-subunit ring-ATPases carry out a myriad of biological functions, including genome packaging in viruses. Though the basic structures and functions of these motors have been well-established, the mechanisms of ATPase firing and motor coordination are poorly understood. Here, using single-molecule fluorescence, we determine that the active bacteriophage T4 DNA packaging motor consists of five subunits of gp17. By systematically doping motors with an ATPase-defective subunit and selecting single motors containing a precise number of active or inactive subunits, we find that the packaging motor can tolerate an inactive subunit. However, motors containing one or more inactive subunits exhibit fewer DNA engagements, a higher failure rate in encapsidation, reduced packaging velocity, and increased pausing. These findings suggest a DNA packaging model in which the motor, by re-adjusting its grip on DNA, can skip an inactive subunit and resume DNA translocation, suggesting that strict coordination amongst motor subunits of packaging motors is not crucial for function.
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43
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Zhuo B, Ou X, Li J. Structure and Mechanical Stabilities of the Three-Way Junction Motifs in Prohead RNA. J Phys Chem B 2021; 125:12125-12134. [PMID: 34719230 DOI: 10.1021/acs.jpcb.1c04681] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The core structure of phi29 prohead RNA (pRNA) is composed of three major helices organized into three-way junction pRNA (3WJ-pRNA) and has stout structural rigidity along the coaxial helices. Prohead RNAs of the other Bacillus subtilis bacteriophages such as GA1 and SF5 share similar secondary structure and function with phi29; whether these pRNAs have similar mechanical rigidity remains to be elucidated. In this study, we constructed the tertiary structures of GA1 and SF5 3WJ-pRNAs by comparative modeling. Both GA1 and SF5 3WJ-pRNAs adopt a similar structure, in which three helices are organized as the three-way junction and two of the three helices are stacked coaxially. Moreover, detailed structural features of GA1 and SF5 3WJ-pRNAs are also similar to those of phi29 3WJ-pRNA: all of the bases of the coaxial helices are paired, and all of the adenines in the junction region are paired, which eliminates the interference of A-minor tertiary interactions. Hence, the coaxial helices tightly join to each other, and the major groove between them is very narrow. Two Mg2+ ions can thus fit into this major groove and form double Mg clamps. A steered molecular dynamics simulation was used to study the mechanical properties of these 3WJ-pRNAs. Both GA1 and SF5 3WJ-pRNAs show strong resistance to applied force in the direction of their coaxial helices. Such mechanical stability can be attributed to the Mg clamps.
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Affiliation(s)
- Boyang Zhuo
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Xinwen Ou
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Jingyuan Li
- Department of Physics, Zhejiang University, Hangzhou 310027, China
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Abstract
Although the process of genome encapsidation is highly conserved in tailed bacteriophages and eukaryotic double-stranded DNA viruses, there are two distinct packaging pathways that these viruses use to catalyze ATP-driven translocation of the viral genome into a preassembled procapsid shell. One pathway is used by ϕ29-like phages and adenoviruses, which replicate and subsequently package a monomeric, unit-length genome covalently attached to a virus/phage-encoded protein at each 5'-end of the dsDNA genome. In a second, more ubiquitous packaging pathway characterized by phage lambda and the herpesviruses, the viral DNA is replicated as multigenome concatemers linked in a head-to-tail fashion. Genome packaging in these viruses thus requires excision of individual genomes from the concatemer that are then translocated into a preassembled procapsid. Hence, the ATPases that power packaging in these viruses also possess nuclease activities that cut the genome from the concatemer at the beginning and end of packaging. This review focuses on proposed mechanisms of genome packaging in the dsDNA viruses using unit-length ϕ29 and concatemeric λ genome packaging motors as representative model systems.
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Affiliation(s)
- Carlos E Catalano
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States.
| | - Marc C Morais
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural and Molecular Biophysics, University of Texas Medical Branch at Galveston, Galveston, TX, United States
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45
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Rao VB, Fokine A, Fang Q. The remarkable viral portal vertex: structure and a plausible model for mechanism. Curr Opin Virol 2021; 51:65-73. [PMID: 34619513 DOI: 10.1016/j.coviro.2021.09.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 08/23/2021] [Accepted: 09/12/2021] [Indexed: 01/20/2023]
Abstract
Many icosahedral viruses including tailed bacteriophages and herpes viruses have a unique portal vertex where a dodecameric protein ring is associated with a fivefold capsid shell. While the peripheral regions of the portal ring are involved in capsid assembly, its central channel is used to transport DNA into and out of capsid during genome packaging and infection. Though the atomic structure of this highly conserved, turbine-shaped, portal is known for nearly two decades, its molecular mechanism remains a mystery. Recent high-resolution in situ structures reveal various conformational states of the portal and the asymmetric interactions between the 12-fold portal and the fivefold capsid. These lead to a valve-like mechanism for this symmetry-mismatched portal vertex that regulates DNA flow through the channel, a critical function for high fidelity assembly of an infectious virion.
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Affiliation(s)
- Venigalla B Rao
- Bacteriophage Medical Research Center, Department of Biology, The Catholic University of America, Washington, DC 20064, USA.
| | - Andrei Fokine
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Qianglin Fang
- School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong, China
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46
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Wangchuk J, Chatterjee A, Patil S, Madugula SK, Kondabagil K. The coevolution of large and small terminases of bacteriophages is a result of purifying selection leading to phenotypic stabilization. Virology 2021; 564:13-25. [PMID: 34598064 DOI: 10.1016/j.virol.2021.09.004] [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: 04/27/2021] [Revised: 09/14/2021] [Accepted: 09/14/2021] [Indexed: 10/20/2022]
Abstract
Genome packaging in many dsDNA phages requires a series of precisely coordinated actions of two phage-coded proteins, namely, large terminase (TerL) and small terminase (TerS) with DNA and ATP, and with each other. Despite the strict functional conservation, TerL and TerS homologs exhibit large sequence variations. We investigated the sequence variability across eight phage types and observed a coevolutionary framework wherein the genealogy of TerL homologs mirrored that of the corresponding TerS homologs. Furthermore, a high purifying selection observed (dN/dS«1) indicated strong structural constraints on both TerL and TerS, and identify coevolving residues in TerL and TerS of phage T4 and lambda. Using the highly coevolving (correlation coefficient of 0.99) TerL and TerS of phage N4, we show that their biochemical features are similar to the phylogenetically divergent phage λ terminases. We also demonstrate using the Surface Plasma Resonance (SPR) technique that phage N4 TerL transiently interacts with TerS.
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Affiliation(s)
- Jigme Wangchuk
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Anirvan Chatterjee
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Supriya Patil
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Santhosh Kumar Madugula
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Kiran Kondabagil
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India.
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47
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Li W, Zhang H, Hu M, Zhu Q, Su H, Li N, Hu H. 3D calibration of microsphere position in optical tweezers using the back-focal-plane interferometry method. OPTICS EXPRESS 2021; 29:32271-32284. [PMID: 34615302 DOI: 10.1364/oe.435592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 09/07/2021] [Indexed: 06/13/2023]
Abstract
This paper presents a method to directly calibrate the position of a trapped micro-sphere in optical tweezers utilizing its interference pattern formed at the back focal plane (BFP). Through finite difference time domain (FDTD) and scalar diffraction theorem, the scattering field complex amplitude of the near and far fields can be simulated after interference between the trapped sphere and focus Gaussian beam. The position of the trapped sphere can be recovered and calibrated based on a back focal plane interferometry (BFPI) algorithm. Theoretical results demonstrate that optical tweezers with a larger numerical aperture (NA) Gaussian beam will yield a better detection sensitivity but with a smaller linear range. These results were experimentally validated by trapping a microsphere in a single beam optical tweezer. We used an extra focused laser to manipulate the trapped sphere and then compared its position in the images and that obtained using the BFP method. The interference pattern from simulation and experiments showed good agreement, implying that the calibration factor can be deduced from simulation and requires no intermediate calculation process. These results provide a pathway to obtain the calibration factor, enable a faster and direct measurement of the sphere position, and show possibilities for adjusting the crosstalk and nonlinearity inside an optical trap.
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48
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Egido JE, Costa AR, Aparicio-Maldonado C, Haas PJ, Brouns SJJ. Mechanisms and clinical importance of bacteriophage resistance. FEMS Microbiol Rev 2021; 46:6374866. [PMID: 34558600 PMCID: PMC8829019 DOI: 10.1093/femsre/fuab048] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 09/15/2021] [Indexed: 12/24/2022] Open
Abstract
We are in the midst of a golden age of uncovering defense systems against bacteriophages. Apart from the fundamental interest in these defense systems, and revolutionary applications that have been derived from them (e.g. CRISPR-Cas9 and restriction endonucleases), it is unknown how defense systems contribute to resistance formation against bacteriophages in clinical settings. Bacteriophages are now being reconsidered as therapeutic agents against bacterial infections due the emergence of multidrug resistance. However, bacteriophage resistance through defense systems and other means could hinder the development of successful phage-based therapies. Here, we review the current state of the field of bacteriophage defense, highlight the relevance of bacteriophage defense for potential clinical use of bacteriophages as therapeutic agents and suggest new directions of research.
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Affiliation(s)
- Julia E Egido
- Medical Microbiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, Netherlands
| | - Ana Rita Costa
- Department of Bionanoscience, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, Netherlands.,Kavli Institute of Nanoscience, Delft, Netherlands.,Fagenbank, Delft, Netherlands
| | - Cristian Aparicio-Maldonado
- Department of Bionanoscience, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, Netherlands.,Kavli Institute of Nanoscience, Delft, Netherlands
| | - Pieter-Jan Haas
- Medical Microbiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, Netherlands
| | - Stan J J Brouns
- Department of Bionanoscience, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, Netherlands.,Kavli Institute of Nanoscience, Delft, Netherlands.,Fagenbank, Delft, Netherlands
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49
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Konyshev I, Byvalov A. Model systems for optical trapping: the physical basis and biological applications. Biophys Rev 2021; 13:515-529. [PMID: 34471436 DOI: 10.1007/s12551-021-00823-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 07/05/2021] [Indexed: 11/30/2022] Open
Abstract
The micromechanical methods, among which optical trapping and atomic force microscopy have a special place, are widespread currently in biology to study molecular interactions between different biological objects. Optical trapping is reported to be quite applicable to study the mechanical properties of surface structures onto bacterial (pili and flagella) and eukaryotic (filopodia) cells. The review briefly summarizes the physical basis of optical trapping, as well as the principles of calculating the van der Waals, electrostatic, and donor-acceptor forces when two microparticles or a microparticle and a flat surface are used. Three main types of model systems (abiotic, biotic, and mixed) used in trapping experiments are described, and the peculiarities of manipulation with living (bacteria, fungal spores, etc.) and non-spherical objects (e.g., rod-shaped bacteria) are summarized.
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Affiliation(s)
- Ilya Konyshev
- Institute of Physiology of Коmi Science Centre of the Ural Branch of the Russian Academy of Sciences, FRC Komi SC UB RAS, Komi Republic, 167982 Syktyvkar, Russian Federation.,Vyatka State University, 36 Moskovskaya str, 610000 Kirov, Russian Federation
| | - Andrey Byvalov
- Institute of Physiology of Коmi Science Centre of the Ural Branch of the Russian Academy of Sciences, FRC Komi SC UB RAS, Komi Republic, 167982 Syktyvkar, Russian Federation.,Vyatka State University, 36 Moskovskaya str, 610000 Kirov, Russian Federation
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50
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Park CB, Sung BJ. Effects of Packaging History on the Ejection of a Polymer Chain from a Small Confinement. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00857] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Chung Bin Park
- Department of Chemistry and Research Institute for Basic Science, Sogang University, Seoul 04107, Republic of Korea
| | - Bong June Sung
- Department of Chemistry and Research Institute for Basic Science, Sogang University, Seoul 04107, Republic of Korea
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