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Chen M, Sahoo B, Mou Z, Song X, Tsai T, Dai X. Genome organization in double-stranded DNA viruses observed by cryoET. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.15.571939. [PMID: 38168199 PMCID: PMC10760162 DOI: 10.1101/2023.12.15.571939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Double-stranded DNA (dsDNA) viruses package their genetic material into protein cages with diameters usually a few hundred times smaller than the length of their genome. Compressing the relatively stiff and highly negatively charged dsDNA into a small volume is energetically costly and mechanistically enigmatic. Multiple models of dsDNA packaging have been proposed based on various experimental evidence and simulation methods, but direct observation of any viral genome organization is lacking. Here, using cryoET and an improved data processing scheme that utilizes information from the encaging protein shell, we present 3D views of dsDNA genome inside individual viral particles at resolution that densities of neighboring DNA duplexes are readily separable. These cryoET observations reveal a "rod-and-coil" fold of the dsDNA that is conserved among herpes simplex virus type 1 (HSV-1) with a spherical capsid, bacteriophage T4 with a prolate capsid, and bacteriophage T7 with a proteinaceous core inside the capsid. Finally, inspired by the genome arrangement in partially packaged T4 particles, we propose a mechanism for the genome packaging process in dsDNA viruses.
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Affiliation(s)
- Muyuan Chen
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, USA
| | - Bibekananda Sahoo
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Zongjun Mou
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Xiyong Song
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Tiffany Tsai
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Xinghong Dai
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
- Lead contact
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2
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Jia X, Gao Y, Huang Y, Sun L, Li S, Li H, Zhang X, Li Y, He J, Wu W, Venkannagari H, Yang K, Baker ML, Zhang Q. Architecture of the baculovirus nucleocapsid revealed by cryo-EM. Nat Commun 2023; 14:7481. [PMID: 37980340 PMCID: PMC10657434 DOI: 10.1038/s41467-023-43284-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 11/03/2023] [Indexed: 11/20/2023] Open
Abstract
Baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV) has been widely used as a bioinsecticide and a protein expression vector. Despite their importance, very little is known about the structure of most baculovirus proteins. Here, we show a 3.2 Å resolution structure of helical cylindrical body of the AcMNPV nucleocapsid, composed of VP39, as well as 4.3 Å resolution structures of both the head and the base of the nucleocapsid composed of over 100 protein subunits. AcMNPV VP39 demonstrates some features of the HK97-like fold and utilizes disulfide-bonds and a set of interactions at its C-termini to mediate nucleocapsid assembly and stability. At both ends of the nucleocapsid, the VP39 cylinder is constricted by an outer shell ring composed of proteins AC104, AC142 and AC109. AC101(BV/ODV-C42) and AC144(ODV-EC27) form a C14 symmetric inner layer at both capsid head and base. In the base, these proteins interact with a 7-fold symmetric capsid plug, while a portal-like structure is seen in the central portion of head. Additionally, we propose an application of AlphaFold2 for model building in intermediate resolution density.
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Affiliation(s)
- Xudong Jia
- State key laboratory of biocontrol, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, China
| | - Yuanzhu Gao
- State key laboratory of biocontrol, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, China
- Cryo-EM Facility Center, Southern University of Science and Technology, Shenzhen, China
| | - Yuxuan Huang
- State key laboratory of biocontrol, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, China
| | - Linjun Sun
- State key laboratory of biocontrol, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, China
| | - Siduo Li
- State key laboratory of biocontrol, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, China
| | - Hongmei Li
- State key laboratory of biocontrol, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, China
| | - Xueqing Zhang
- State key laboratory of biocontrol, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, China
| | - Yinyin Li
- State key laboratory of biocontrol, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, China
| | - Jian He
- State key laboratory of biocontrol, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, China
| | - Wenbi Wu
- State key laboratory of biocontrol, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, China
| | - Harikanth Venkannagari
- Department of Biochemistry and Molecular Biology, McGovern Medical School at the University of Texas Health Science Center, Houston, TX, 77030, USA
| | - Kai Yang
- State key laboratory of biocontrol, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, China
| | - Matthew L Baker
- Department of Biochemistry and Molecular Biology, McGovern Medical School at the University of Texas Health Science Center, Houston, TX, 77030, USA.
| | - Qinfen Zhang
- State key laboratory of biocontrol, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, China.
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3
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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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4
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Zhu D, Cao D, Zhang X. Virus structures revealed by advanced cryoelectron microscopy methods. Structure 2023; 31:1348-1359. [PMID: 37797619 DOI: 10.1016/j.str.2023.09.008] [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: 06/27/2023] [Revised: 08/25/2023] [Accepted: 09/11/2023] [Indexed: 10/07/2023]
Abstract
Before the resolution revolution, cryoelectron microscopy (cryo-EM) single-particle analysis (SPA) already achieved resolutions beyond 4 Å for certain icosahedral viruses, enabling ab initio atomic model building of these viruses. As the only samples that achieved such high resolution at that time, cryo-EM method development was closely intertwined with the improvement of reconstructions of symmetrical viruses. Viral morphology exhibits significant diversity, ranging from small to large, uniform to non-uniform, and from containing single symmetry to multiple symmetries. Furthermore, viruses undergo conformational changes during their life cycle. Several methods, such as asymmetric reconstruction, Ewald sphere correction, cryoelectron tomography (cryo-ET), and sub-tomogram averaging (STA), have been developed and applied to determine virus structures in vivo and in vitro. This review outlines current advanced cryo-EM methods for high-resolution structure determination of viruses and summarizes accomplishments obtained with these approaches. Moreover, persisting challenges in comprehending virus structures are discussed and we propose potential solutions.
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Affiliation(s)
- Dongjie Zhu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Duanfang Cao
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinzheng Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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5
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Zheng J, Chen W, Xiao H, Yang F, Song J, Cheng L, Liu H. Asymmetric Structure of Podophage GP4 Reveals a Novel Architecture of Three Types of Tail Fibers. J Mol Biol 2023; 435:168258. [PMID: 37660940 DOI: 10.1016/j.jmb.2023.168258] [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: 06/15/2023] [Revised: 08/28/2023] [Accepted: 08/28/2023] [Indexed: 09/05/2023]
Abstract
Bacteriophage tail fibers (or called tail spikes) play a critical role in the early stage of infection by binding to the bacterial surface. Podophages with known structures usually possess one or two types of fibers. Here, we resolved an asymmetric structure of the podophage GP4 to near-atomic resolution by cryo-EM. Our structure revealed a symmetry-mismatch relationship between the components of the GP4 tail with previously unseen topologies. In detail, two dodecameric adaptors (adaptors I and II), a hexameric nozzle, and a tail needle form a conserved tail body connected to a dodecameric portal occupying a unique vertex of the icosahedral head. However, five chain-like extended fibers (fiber I) and five tulip-like short fibers (fiber II) are anchored to a 15-fold symmetric fiber-tail adaptor, encircling the adaptor I, and six bamboo-like trimeric fibers (fiber III) are connected to the nozzle. Five fibers I, each composed of five dimers of the protein gp80 linked by an elongated rope protein, are attached to the five edges of the tail vertex of the icosahedral head. In this study, we identified a new structure of the podophage with three types of tail fibers, and such phages with different types of fibers may have a broad host range and/or infect host cells with considerably high efficiency, providing evolutionary advantages in harsh environments.
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Affiliation(s)
- Jing Zheng
- Institute of Interdisciplinary Studies, Key Laboratory for Matter Microstructure and Function of Hunan Province, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control, School of Physics and Electronics, Hunan Normal University, Changsha 410082, China
| | - Wenyuan Chen
- Institute of Interdisciplinary Studies, Key Laboratory for Matter Microstructure and Function of Hunan Province, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control, School of Physics and Electronics, Hunan Normal University, Changsha 410082, China
| | - Hao Xiao
- Institute of Interdisciplinary Studies, Key Laboratory for Matter Microstructure and Function of Hunan Province, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control, School of Physics and Electronics, Hunan Normal University, Changsha 410082, China; State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 100052, China
| | - Fan Yang
- Institute of Interdisciplinary Studies, Key Laboratory for Matter Microstructure and Function of Hunan Province, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control, School of Physics and Electronics, Hunan Normal University, Changsha 410082, China
| | - Jingdong Song
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 100052, China
| | - Lingpeng Cheng
- Institute of Interdisciplinary Studies, Key Laboratory for Matter Microstructure and Function of Hunan Province, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control, School of Physics and Electronics, Hunan Normal University, Changsha 410082, China.
| | - Hongrong Liu
- Institute of Interdisciplinary Studies, Key Laboratory for Matter Microstructure and Function of Hunan Province, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control, School of Physics and Electronics, Hunan Normal University, Changsha 410082, China.
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6
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Jia Q, Xiang Y. Cryo-EM structure of a bacteriophage M13 mini variant. Nat Commun 2023; 14:5421. [PMID: 37669979 PMCID: PMC10480500 DOI: 10.1038/s41467-023-41151-7] [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: 03/28/2023] [Accepted: 08/24/2023] [Indexed: 09/07/2023] Open
Abstract
Filamentous bacteriophages package their circular, single stranded DNA genome with the major coat protein pVIII and the minor coat proteins pIII, pVII, pVI, and pIX. Here, we report the cryo-EM structure of a ~500 Å long bacteriophage M13 mini variant. The distal ends of the mini phage are sealed by two cap-like complexes composed of the minor coat proteins. The top cap complex consists of pVII and pIX, both exhibiting a single helix structure. Arg33 of pVII and Glu29 of pIX, located on the inner surface of the cap, play a key role in recognizing the genome packaging signal. The bottom cap complex is formed by the hook-like structures of pIII and pVI, arranged in helix barrels. Most of the inner ssDNA genome adopts a double helix structure with a similar pitch to that of the A-form double-stranded DNA. These findings provide insights into the assembly of filamentous bacteriophages.
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Affiliation(s)
- Qi Jia
- Beijing Frontier Research Center for Biological Structure, Center for Infectious Disease Research, SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing, 100084, P.R. China
| | - Ye Xiang
- Beijing Frontier Research Center for Biological Structure, Center for Infectious Disease Research, SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing, 100084, P.R. China.
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7
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Uezu S, Yamamoto T, Oide M, Takayama Y, Okajima K, Kobayashi A, Yamamoto M, Nakasako M. Ultrastructure and fractal property of chromosomes in close-to-native yeast nuclei visualized using X-ray laser diffraction. Sci Rep 2023; 13:10802. [PMID: 37407674 DOI: 10.1038/s41598-023-37733-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 06/27/2023] [Indexed: 07/07/2023] Open
Abstract
Genome compaction and activity in the nucleus depend on spatiotemporal changes in the organization of chromatins in chromosomes. However, the direct imaging of the chromosome structures in the nuclei has been difficult and challenging. Herein, we directly visualized the structure of chromosomes in frozen-hydrated nuclei of budding yeast in the interphase using X-ray laser diffraction. The reconstructed projection electron density maps revealed inhomogeneous distributions of chromosomes, such as a 300 nm assembly and fibrous substructures in the elliptic-circular shaped nuclei of approximately 800 nm. In addition, from the diffraction patterns, we confirmed the absence of regular arrangements of chromosomes and chromatins with 400-20 nm spacing, and demonstrated that chromosomes were composed of self-similarly assembled substructural domains with an average radius of gyration of 58 nm and smooth surfaces. Based on these analyses, we constructed putative models to discuss the organization of 16 chromosomes, carrying DNA of 4.1 mm in 800 nm ellipsoid of the nucleus at the interphase. We anticipate the structural parameters on the fractal property of chromosomes and the experimental images to be a starting point for constructing more sophisticated 3D structural models of the nucleus.
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Grants
- XFEL key technology and the X-ray Free Electron Laser Priority Strategy Program the Ministry of Education, Culture, Sports, Science and Technology, Japan
- jp23120525 the Ministry of Education, Culture, Sports, Science and Technology, Japan
- jp25120725 the Ministry of Education, Culture, Sports, Science and Technology, Japan
- jp15H01647 the Ministry of Education, Culture, Sports, Science and Technology, Japan
- jp24113723 the Ministry of Education, Culture, Sports, Science and Technology, Japan
- jp26104535 the Ministry of Education, Culture, Sports, Science and Technology, Japan
- jp24654140 the Japan Society for the Promotion of Science
- jp1920402 the Japan Society for the Promotion of Science
- jp16H02218 the Japan Society for the Promotion of Science
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Affiliation(s)
- So Uezu
- Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-Ku, Yokohama, Kanagawa, 223-8522, Japan
- RIKEN, Spring-8 Center, 1-1-1 Kouto, Sayo-Cho, Sayogun, Hyogo, 679-5148, Japan
| | - Takahiro Yamamoto
- Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-Ku, Yokohama, Kanagawa, 223-8522, Japan
- RIKEN, Spring-8 Center, 1-1-1 Kouto, Sayo-Cho, Sayogun, Hyogo, 679-5148, Japan
| | - Mao Oide
- Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-Ku, Yokohama, Kanagawa, 223-8522, Japan
- RIKEN, Spring-8 Center, 1-1-1 Kouto, Sayo-Cho, Sayogun, Hyogo, 679-5148, Japan
- PRESTO, Japan Science and Technology Agency, Chiyoda-Ku, Tokyo, 102-0076, Japan
| | - Yuki Takayama
- RIKEN, Spring-8 Center, 1-1-1 Kouto, Sayo-Cho, Sayogun, Hyogo, 679-5148, Japan
- Graduate School of Science, University of Hyogo, 3-2-1 Kouto, Kamigori-Cho, Ako-Gun, Hyogo, 678-1297, Japan
- International Center for Synchrotron Radiation Innovation Smart, Tohoku University, Katahira 2-1-1, Aoba-Ku, Sendai, 980-8577, Japan
- CRESTO, Japan Science and Technology Agency, Chiyoda-Ku, Tokyo, 102-0076, Japan
| | - Koji Okajima
- Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-Ku, Yokohama, Kanagawa, 223-8522, Japan
- RIKEN, Spring-8 Center, 1-1-1 Kouto, Sayo-Cho, Sayogun, Hyogo, 679-5148, Japan
| | - Amane Kobayashi
- Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-Ku, Yokohama, Kanagawa, 223-8522, Japan
- RIKEN, Spring-8 Center, 1-1-1 Kouto, Sayo-Cho, Sayogun, Hyogo, 679-5148, Japan
| | - Masaki Yamamoto
- RIKEN, Spring-8 Center, 1-1-1 Kouto, Sayo-Cho, Sayogun, Hyogo, 679-5148, Japan
| | - Masayoshi Nakasako
- Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-Ku, Yokohama, Kanagawa, 223-8522, Japan.
- RIKEN, Spring-8 Center, 1-1-1 Kouto, Sayo-Cho, Sayogun, Hyogo, 679-5148, Japan.
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Zhang Q, Gao Y, Baker ML, Liu S, Jia X, Xu H, He J, Kaelber JT, Weng S, Jiang W. The structure of a 12-segmented dsRNA reovirus: New insights into capsid stabilization and organization. PLoS Pathog 2023; 19:e1011341. [PMID: 37083840 PMCID: PMC10155992 DOI: 10.1371/journal.ppat.1011341] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 05/03/2023] [Accepted: 04/02/2023] [Indexed: 04/22/2023] Open
Abstract
Infecting a wide range of hosts, members of Reovirales (formerly Reoviridae) consist of a genome with different numbers of segmented double stranded RNAs (dsRNA) encapsulated by a proteinaceous shell and carry out genome replication and transcription inside the virion. Several cryo-electron microscopy (cryo-EM) structures of reoviruses with 9, 10 or 11 segmented dsRNA genomes have revealed insights into genome arrangement and transcription. However, the structure and genome arrangement of 12-segmented Reovirales members remain poorly understood. Using cryo-EM, we determined the structure of mud crab reovirus (MCRV), a 12-segmented dsRNA virus that is a putative member of Reovirales in the non-turreted Sedoreoviridae family, to near-atomic resolutions with icosahedral symmetry (3.1 Å) and without imposing icosahedral symmetry (3.4 Å). These structures revealed the organization of the major capsid proteins in two layers: an outer T = 13 layer consisting of VP12 trimers and unique VP11 clamps, and an inner T = 1 layer consisting of VP3 dimers. Additionally, ten RNA dependent RNA polymerases (RdRp) were well resolved just below the VP3 layer but were offset from the 5-fold axes and arranged with D5 symmetry, which has not previously been seen in other members of Reovirales. The N-termini of VP3 were shown to adopt four unique conformations; two of which anchor the RdRps, while the other two conformations are likely involved in genome organization and capsid stability. Taken together, these structures provide a new level of understanding for capsid stabilization and genome organization of segmented dsRNA viruses.
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Affiliation(s)
- Qinfen Zhang
- State key lab for biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yuanzhu Gao
- State key lab for biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Matthew L Baker
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School at the University of Texas Health Science Center, Houston, Texas, United States of America
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Shanshan Liu
- State key lab for biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Xudong Jia
- State key lab for biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Haidong Xu
- State key lab for biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jianguo He
- State key lab for biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jason T Kaelber
- Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Shaoping Weng
- State key lab for biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Wen Jiang
- Markey Center for Structural Biology, Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
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9
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Tail proteins of phage SU10 reorganize into the nozzle for genome delivery. Nat Commun 2022; 13:5622. [PMID: 36153309 PMCID: PMC9509320 DOI: 10.1038/s41467-022-33305-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 09/12/2022] [Indexed: 12/23/2022] Open
Abstract
Escherichia coli phage SU10 belongs to the genus Kuravirus from the class Caudoviricetes of phages with short non-contractile tails. In contrast to other short-tailed phages, the tails of Kuraviruses elongate upon cell attachment. Here we show that the virion of SU10 has a prolate head, containing genome and ejection proteins, and a tail, which is formed of portal, adaptor, nozzle, and tail needle proteins and decorated with long and short fibers. The binding of the long tail fibers to the receptors in the outer bacterial membrane induces the straightening of nozzle proteins and rotation of short tail fibers. After the re-arrangement, the nozzle proteins and short tail fibers alternate to form a nozzle that extends the tail by 28 nm. Subsequently, the tail needle detaches from the nozzle proteins and five types of ejection proteins are released from the SU10 head. The nozzle with the putative extension formed by the ejection proteins enables the delivery of the SU10 genome into the bacterial cytoplasm. It is likely that this mechanism of genome delivery, involving the formation of the tail nozzle, is employed by all Kuraviruses. E. coli phage SU10 has a short non-contractile tail. Here, the authors show that after cell binding, nozzle proteins and tail fibers of SU10 change conformation to form a nozzle that enables the delivery of the phage DNA into the bacterial cytoplasm.
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10
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David Hou CF, Swanson NA, Li F, Yang R, Lokareddy RK, Cingolani G. Cryo-EM structure of a kinetically trapped dodecameric portal protein from the Pseudomonas-phage PaP3. J Mol Biol 2022; 434:167537. [DOI: 10.1016/j.jmb.2022.167537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 02/09/2022] [Accepted: 03/04/2022] [Indexed: 10/18/2022]
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11
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Swanson NA, Hou CFD, Cingolani G. Viral Ejection Proteins: Mosaically Conserved, Conformational Gymnasts. Microorganisms 2022; 10:microorganisms10030504. [PMID: 35336080 PMCID: PMC8954989 DOI: 10.3390/microorganisms10030504] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 02/18/2022] [Accepted: 02/22/2022] [Indexed: 11/16/2022] Open
Abstract
Bacterial viruses (or bacteriophages) have developed formidable ways to deliver their genetic information inside bacteria, overcoming the complexity of the bacterial-cell envelope. In short-tailed phages of the Podoviridae superfamily, genome ejection is mediated by a set of mysterious internal virion proteins, also called ejection or pilot proteins, which are required for infectivity. The ejection proteins are challenging to study due to their plastic structures and transient assembly and have remained less characterized than classical components such as the phage coat protein or terminase subunit. However, a spate of recent cryo-EM structures has elucidated key features underscoring these proteins' assembly and conformational gymnastics that accompany their expulsion from the virion head through the portal protein channel into the host. In this review, we will use a phage-T7-centric approach to critically review the status of the literature on ejection proteins, decipher the conformational changes of T7 ejection proteins in the pre- and post-ejection conformation, and predict the conservation of these proteins in other Podoviridae. The challenge is to relate the structure of the ejection proteins to the mechanisms of genome ejection, which are exceedingly complex and use the host's machinery.
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Affiliation(s)
- Nicholas A. Swanson
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA; (N.A.S.); (C.-F.D.H.)
- Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02139, USA
| | - Chun-Feng D. Hou
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA; (N.A.S.); (C.-F.D.H.)
| | - Gino Cingolani
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA; (N.A.S.); (C.-F.D.H.)
- Correspondence: ; Tel.: +01-(215)-503-4573
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12
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Structural changes in bacteriophage T7 upon receptor-induced genome ejection. Proc Natl Acad Sci U S A 2021; 118:2102003118. [PMID: 34504014 DOI: 10.1073/pnas.2102003118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/29/2021] [Indexed: 12/11/2022] Open
Abstract
Many tailed bacteriophages assemble ejection proteins and a portal-tail complex at a unique vertex of the capsid. The ejection proteins form a transenvelope channel extending the portal-tail channel for the delivery of genomic DNA in cell infection. Here, we report the structure of the mature bacteriophage T7, including the ejection proteins, as well as the structures of the full and empty T7 particles in complex with their cell receptor lipopolysaccharide. Our near-atomic-resolution reconstruction shows that the ejection proteins in the mature T7 assemble into a core, which comprises a fourfold gene product 16 (gp16) ring, an eightfold gp15 ring, and a putative eightfold gp14 ring. The gp15 and gp16 are mainly composed of helix bundles, and gp16 harbors a lytic transglycosylase domain for degrading the bacterial peptidoglycan layer. When interacting with the lipopolysaccharide, the T7 tail nozzle opens. Six copies of gp14 anchor to the tail nozzle, extending the nozzle across the lipopolysaccharide lipid bilayer. The structures of gp15 and gp16 in the mature T7 suggest that they should undergo remarkable conformational changes to form the transenvelope channel. Hydrophobic α-helices were observed in gp16 but not in gp15, suggesting that gp15 forms the channel in the hydrophilic periplasm and gp16 forms the channel in the cytoplasmic membrane.
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13
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Hiltner L, Carme Calderer M, Arsuaga J, Vázquez M. Chromonic liquid crystals and packing configurations of bacteriophage viruses. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2021; 379:20200111. [PMID: 34024128 DOI: 10.1098/rsta.2020.0111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/01/2020] [Indexed: 06/12/2023]
Abstract
We study equilibrium configurations of hexagonal columnar liquid crystals in the context of characterizing packing structures of bacteriophage viruses in a protein capsid. These are viruses that infect bacteria and are currently the focus of intense research efforts, with the goal of finding new therapies for bacteria-resistant antibiotics. The energy that we propose consists of the Oseen-Frank free energy of nematic liquid crystals that penalizes bending of the columnar directions, in addition to the cross-sectional elastic energy accounting for distortions of the transverse hexagonal structure; we also consider the isotropic contribution of the core and the energy of the unknown interface between the outer ordered region of the capsid and the inner disordered core. The problem becomes of free boundary type, with constraints. We show that the concentric, azimuthal, spool-like configuration is the absolute minimizer. Moreover, we present examples of toroidal structures formed by DNA in free solution and compare them with the analogous ones occurring in experiments with other types of lyotropic liquid crystals, such as food dyes and additives. This article is part of the theme issue 'Topics in mathematical design of complex materials'.
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Affiliation(s)
- Lindsey Hiltner
- School of Mathematics, University of Minnesota, Minneapolis, MN 55442, USA
| | - M Carme Calderer
- School of Mathematics, University of Minnesota, Minneapolis, MN 55442, USA
| | - Javier Arsuaga
- Department of Cellular and Molecular Biology, Briggs Hall, Davis, CA 09
- Department of Mathematics, MSB, 2115, University of California Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Mariel Vázquez
- Department of Mathematics, MSB, 2150, University of California Davis, One Shields Avenue, Davis, CA 95616, USA
- Department of Microbiology and Molecular Genetics, Briggs Hall, Davis, CA 09
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14
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Swanson NA, Lokareddy RK, Li F, Hou CFD, Leptihn S, Pavlenok M, Niederweis M, Pumroy RA, Moiseenkova-Bell VY, Cingolani G. Cryo-EM structure of the periplasmic tunnel of T7 DNA-ejectosome at 2.7 Å resolution. Mol Cell 2021; 81:3145-3159.e7. [PMID: 34214465 DOI: 10.1016/j.molcel.2021.06.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 03/27/2021] [Accepted: 06/01/2021] [Indexed: 11/15/2022]
Abstract
Hershey and Chase used bacteriophage T2 genome delivery inside Escherichia coli to demonstrate that DNA, not protein, is the genetic material. Seventy years later, our understanding of viral genome delivery in prokaryotes remains limited, especially for short-tailed phages of the Podoviridae family. These viruses expel mysterious ejection proteins found inside the capsid to form a DNA-ejectosome for genome delivery into bacteria. Here, we reconstitute the phage T7 DNA-ejectosome components gp14, gp15, and gp16 and solve the periplasmic tunnel structure at 2.7 Å resolution. We find that gp14 forms an outer membrane pore, gp15 assembles into a 210 Å hexameric DNA tube spanning the host periplasm, and gp16 extends into the host cytoplasm forming a ∼4,200 residue hub. Gp16 promotes gp15 oligomerization, coordinating peptidoglycan hydrolysis, DNA binding, and lipid insertion. The reconstituted gp15:gp16 complex lacks channel-forming activity, suggesting that the pore for DNA passage forms only transiently during genome ejection.
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Affiliation(s)
- Nicholas A Swanson
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
| | - Ravi K Lokareddy
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
| | - Fenglin Li
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
| | - Chun-Feng David Hou
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
| | - Sebastian Leptihn
- Zhejiang University-University of Edinburgh Institute, School of Medicine, Hangzhou, China
| | - Mikhail Pavlenok
- Department of Microbiology, University of Alabama at Birmingham, 845 19th Street South, Birmingham, AL 35294, USA
| | - Michael Niederweis
- Department of Microbiology, University of Alabama at Birmingham, 845 19th Street South, Birmingham, AL 35294, USA
| | - Ruth A Pumroy
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Vera Y Moiseenkova-Bell
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gino Cingolani
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA.
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15
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Nikoubashman A. Ordering, phase behavior, and correlations of semiflexible polymers in confinement. J Chem Phys 2021; 154:090901. [DOI: 10.1063/5.0038052] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Affiliation(s)
- Arash Nikoubashman
- Institute of Physics, Johannes Gutenberg University Mainz, Staudingerweg 7, 55128 Mainz, Germany
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16
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Dou T, Li Z, Zhang J, Evilevitch A, Kurouski D. Nanoscale Structural Characterization of Individual Viral Particles Using Atomic Force Microscopy Infrared Spectroscopy (AFM-IR) and Tip-Enhanced Raman Spectroscopy (TERS). Anal Chem 2020; 92:11297-11304. [PMID: 32683857 DOI: 10.1021/acs.analchem.0c01971] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Viruses are infections species that infect a large spectrum of living systems. Although displaying a wide variety of shapes and sizes, they are all composed of nucleic acid encapsulated into a protein capsid. After virions enter the host cell, they replicate to produce multiple copies of themselves. They then lyse the host, releasing virions to infect new cells. The high proliferation rate of viruses is the underlying cause of their fast transmission among living species. Although many viruses are harmless, some of them are responsible for severe diseases such as AIDS, viral hepatitis, and flu. Traditionally, electron microscopy is used to identify and characterize viruses. This approach is time- and labor-consuming, which is problematic upon pandemic proliferation of previously unknown viruses, such as H1N1 and COVID-19. Herein, we demonstrate a novel diagnosis approach for label-free identification and structural characterization of individual viruses that is based on a combination of nanoscale Raman and infrared spectroscopy. Using atomic force microscopy-infrared (AFM-IR) spectroscopy, we were able to probe structural organization of the virions of Herpes Simplex Type 1 viruses and bacteriophage MS2. We also showed that tip-enhanced Raman spectroscopy (TERS) could be used to reveal protein secondary structure and amino acid composition of the virus surface. Our results show that AFM-IR and TERS provide different but complementary information about the structure of complex biological specimens. This structural information can be used for fast and reliable identification of viruses. This nanoscale bimodal imaging approach can be also used to investigate the origin of viral polymorphism and study mechanisms of virion assembly.
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Affiliation(s)
- Tianyi Dou
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, United States
| | - Zhandong Li
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, United States
| | - Junjie Zhang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, United States.,Center for Phage Technology, Texas A&M University, College Station, Texas 77843, United States
| | - Alex Evilevitch
- Department of Experimental Medical Science, Virus Biophysics Group, BMC Biomedical Center, Lund University, Lund, SE-221 00S, Sweden
| | - Dmitry Kurouski
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, United States
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17
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Sun C, Gonzalez B, Vago FS, Jiang W. High resolution single particle Cryo-EM refinement using JSPR. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 160:37-42. [PMID: 32622834 DOI: 10.1016/j.pbiomolbio.2020.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 05/06/2020] [Accepted: 05/09/2020] [Indexed: 11/30/2022]
Abstract
JSPR is a single particle cryo-EM image processing and 3D reconstruction software developed in the Jiang laboratory at Purdue University. It began as a few refinement scripts for symmetric and asymmetric reconstructions of icosahedral viruses, but has grown into a comprehensive suite of tools for building ab initio reconstructions, high resolution refinements of viruses, protein complexes of arbitrary symmetries including helical tubes/filaments, and image file handling utilities. In this review, we will present examples achieved using JSPR and demonstrate recently implemented features of JSPR such as multi-aberration "alignments" and automatic optimization of masking for the assessment of map resolution using "true" FSC.
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Affiliation(s)
- Chen Sun
- Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN, 47906, USA
| | - Brenda Gonzalez
- Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN, 47906, USA
| | - Frank S Vago
- Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN, 47906, USA
| | - Wen Jiang
- Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN, 47906, USA.
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18
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Translation of the long-term fundamental studies on viral DNA packaging motors into nanotechnology and nanomedicine. SCIENCE CHINA-LIFE SCIENCES 2020; 63:1103-1129. [DOI: 10.1007/s11427-020-1752-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 06/04/2020] [Indexed: 02/07/2023]
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19
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Kaelber JT, Jiang W, Weaver SC, Auguste AJ, Chiu W. Arrangement of the Polymerase Complexes inside a Nine-Segmented dsRNA Virus. Structure 2020; 28:604-612.e3. [PMID: 32049031 PMCID: PMC7289189 DOI: 10.1016/j.str.2020.01.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 12/18/2019] [Accepted: 01/17/2020] [Indexed: 12/15/2022]
Abstract
Members of the family Reoviridae package several copies of the viral polymerase complex into their capsid to carry out replication and transcription within viral particles. Classical single-particle reconstruction encounters difficulties resolving structures such as the intraparticle polymerase complex because refinement can converge to an incorrect map and because the map could depict a nonrepresentative subset of particles or an average of heterogeneous particles. Using the nine-segmented Fako virus, we tested hypotheses for the arrangement and number of polymerase complexes within the virion by measuring how well each hypothesis describes the set of cryoelectron microscopy images of individual viral particles. We find that the polymerase complex in Fako virus binds at ten possible sites despite having only nine genome segments. A single asymmetric configuration describes the arrangement of these complexes in both virions and genome-free capsids. Similarities between the arrangements of Reoviridae with 9, 10, and 11 segments indicate the generalizability of this architecture.
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Affiliation(s)
- Jason T Kaelber
- Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ, USA.
| | - Wen Jiang
- Markey Center for Structural Biology, Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Scott C Weaver
- Institute for Human Infections and Immunity, World Reference Center for Emerging Viruses and Arboviruses, Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA
| | - Albert J Auguste
- Institute for Human Infections and Immunity, World Reference Center for Emerging Viruses and Arboviruses, Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA; Department of Entomology, Fralin Life Science Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Wah Chiu
- Department of Bioengineering, Department of Microbiology and Immunology, and James H. Clark Center, Stanford University, Stanford, CA, USA
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20
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González B, Monroe L, Li K, Yan R, Wright E, Walter T, Kihara D, Weintraub ST, Thomas JA, Serwer P, Jiang W. Phage G Structure at 6.1 Å Resolution, Condensed DNA, and Host Identity Revision to a Lysinibacillus. J Mol Biol 2020; 432:4139-4153. [PMID: 32454153 DOI: 10.1016/j.jmb.2020.05.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 05/21/2020] [Accepted: 05/21/2020] [Indexed: 11/16/2022]
Abstract
Phage G has the largest capsid and genome of any known propagated phage. Many aspects of its structure, assembly, and replication have not been elucidated. Herein, we present the dsDNA-packed and empty phage G capsid at 6.1 and 9 Å resolution, respectively, using cryo-EM for structure determination and mass spectrometry for protein identification. The major capsid protein, gp27, is identified and found to share the HK97-fold universally conserved in all previously solved dsDNA phages. Trimers of the decoration protein, gp26, sit on the 3-fold axes and are thought to enhance the interactions of the hexameric capsomeres of gp27, for other phages encoding decoration proteins. Phage G's decoration protein is longer than what has been reported in other phages, and we suspect the extra interaction surface area helps stabilize the capsid. We identified several additional capsid proteins, including a candidate for the prohead protease responsible for processing gp27. Furthermore, cryo-EM reveals a range of partially full, condensed DNA densities that appear to have no contact with capsid shell. Three analyses confirm that the phage G host is a Lysinibacillus, and not Bacillus megaterium: identity of host proteins in our mass spectrometry analyses, genome sequence of the phage G host, and host range of phage G.
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Affiliation(s)
- Brenda González
- Department of Biological Sciences, Hockmeyer Hall of Structural Biology, Purdue University, 240 South Martin Jischke Drive, West Lafayette, IN 47907-1971, USA
| | - Lyman Monroe
- Department of Biological Sciences, Hockmeyer Hall of Structural Biology, Purdue University, 240 South Martin Jischke Drive, West Lafayette, IN 47907-1971, USA
| | - Kunpeng Li
- Department of Biological Sciences, Hockmeyer Hall of Structural Biology, Purdue University, 240 South Martin Jischke Drive, West Lafayette, IN 47907-1971, USA
| | - Rui Yan
- Department of Biological Sciences, Hockmeyer Hall of Structural Biology, Purdue University, 240 South Martin Jischke Drive, West Lafayette, IN 47907-1971, USA
| | - Elena Wright
- Department of Biochemistry and Structural Biology, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA
| | - Thomas Walter
- Department of Biological Sciences, Hockmeyer Hall of Structural Biology, Purdue University, 240 South Martin Jischke Drive, West Lafayette, IN 47907-1971, USA
| | - Daisuke Kihara
- Department of Biological Sciences, Hockmeyer Hall of Structural Biology, Purdue University, 240 South Martin Jischke Drive, West Lafayette, IN 47907-1971, USA; Department of Computer Science, Purdue University, 305 North University Street, West Lafayette, IN 47907-2107, USA
| | - Susan T Weintraub
- Department of Biochemistry and Structural Biology, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA
| | - Julie A Thomas
- Gosnell School of Life Sciences, Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, NY 14623, USA
| | - Philip Serwer
- Department of Biochemistry and Structural Biology, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA
| | - Wen Jiang
- Department of Biological Sciences, Hockmeyer Hall of Structural Biology, Purdue University, 240 South Martin Jischke Drive, West Lafayette, IN 47907-1971, USA; Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907-2084, USA; Purdue Cryo-EM Facility, Purdue University, Hockmeyer Hall of Structural Biology, 240 South Martin Jischke Drive, West Lafayette, IN 47907-1971, USA; Purdue Center for Cancer Research, Purdue University, 201 South University Street, West Lafayette, IN 47907, USA; Purdue Institute for Infectious, Immunology and Inflammatory Diseases, Purdue University, 207 South Martin Jischke Drive, West Lafayette, IN 47907, USA; Purdue Institute for Drug Discovery, Purdue University, 720 Clinic Drive, West Lafayette, IN 47097, USA.
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21
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Walker S, Arsuaga J, Hiltner L, Calderer MC, Vázquez M. Fine structure of viral dsDNA encapsidation. Phys Rev E 2020; 101:022703. [PMID: 32168691 DOI: 10.1103/physreve.101.022703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 12/19/2019] [Indexed: 06/10/2023]
Abstract
Unraveling the mechanisms of packing of DNA inside viral capsids is of fundamental importance to understanding the spread of viruses. It could also help develop new applications to targeted drug delivery devices for a large range of therapies. In this article, we present a robust, predictive mathematical model and its numerical implementation to aid the study and design of bacteriophage viruses for application purposes. Exploiting the analogies between the columnar hexagonal chromonic phases of encapsidated viral DNA and chromonic aggregates formed by plank-shaped molecular compounds, we develop a first-principles effective mechanical model of DNA packing in a viral capsid. The proposed expression of the packing energy, which combines relevant aspects of the liquid crystal theory, is developed from the model of hexagonal columnar phases, together with that describing configurations of polymeric liquid crystals. The method also outlines a parameter selection strategy that uses available data for a collection of viruses, aimed at applications to viral design. The outcome of the work is a mathematical model and its numerical algorithm, based on the method of finite elements, and computer simulations to identify and label the ordered and disordered regions of the capsid and calculate the inner pressure. It also presents the tools for the local reconstruction of the DNA "scaffolding" and the center curve of the filament within the capsid.
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Affiliation(s)
- Shawn Walker
- Department of Mathematics, 303 Lockett Hall, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Javier Arsuaga
- Department of Cellular and Molecular Biology, Briggs Hall 09, and Department of Mathematics, MSB 2115, University of California Davis, Davis, California 95616, USA
| | - Lindsey Hiltner
- School of Mathematics, 507 Vincent Hall, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - M Carme Calderer
- School of Mathematics, 507 Vincent Hall, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Mariel Vázquez
- Department of Microbiology and Molecular Genetics, Briggs Hall 09, and Department of Mathematics, MSB 2150, University of California Davis, Davis, California 95616, USA
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22
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Dearnaley WJ, Schleupner B, Varano AC, Alden NA, Gonzalez F, Casasanta MA, Scharf BE, Dukes MJ, Kelly DF. Liquid-Cell Electron Tomography of Biological Systems. NANO LETTERS 2019; 19:6734-6741. [PMID: 31244227 PMCID: PMC6786937 DOI: 10.1021/acs.nanolett.9b01309] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Liquid-cell electron microscopy is a rapidly growing field in the imaging domain. While real-time observations are readily available to analyze materials and biological systems, these measurementshave been limited to the two-dimensional (2-D) image plane. Here, we introduce an exciting technical advance to image materials in 3-D while enclosed in liquid. The development of liquid-cell electron tomography permitted us to observe and quantify host-pathogen interactions in solution while contained in the vacuum system of the electron microscope. In doing so, we demonstrate new insights for the rules of engagement involving a unique bacteriophage and its host bacterium. A deeper analysis of the genetic content of the phage pathogens revealed structural features of the infectious units while introducing a new paradigm for host interactions. Overall, we demonstrate a technological opportunity to elevate research efforts for in situ imaging while providing a new level of dimensionality beyond the current state of the field.
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Affiliation(s)
- William J. Dearnaley
- Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Center for Structural Oncology, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Virginia Tech Carilion Research Institute, Virginia Tech, Roanoke, Virginia 24016, United States
| | - Beatrice Schleupner
- Virginia Tech Carilion Research Institute, Virginia Tech, Roanoke, Virginia 24016, United States
| | - A. Cameron Varano
- Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Center for Structural Oncology, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Virginia Tech Carilion Research Institute, Virginia Tech, Roanoke, Virginia 24016, United States
| | - Nick A. Alden
- Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Virginia Tech Carilion Research Institute, Virginia Tech, Roanoke, Virginia 24016, United States
| | - Floricel Gonzalez
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Michael A. Casasanta
- Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Center for Structural Oncology, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Birgit E. Scharf
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Madeline J. Dukes
- Applications Science, Protochips Inc., Morrisville, North Carolina 27560, United States
| | - Deborah F. Kelly
- Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Center for Structural Oncology, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Virginia Tech Carilion Research Institute, Virginia Tech, Roanoke, Virginia 24016, United States
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23
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Hrebík D, Štveráková D, Škubník K, Füzik T, Pantůček R, Plevka P. Structure and genome ejection mechanism of Staphylococcus aureus phage P68. SCIENCE ADVANCES 2019; 5:eaaw7414. [PMID: 31663016 PMCID: PMC6795507 DOI: 10.1126/sciadv.aaw7414] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 09/23/2019] [Indexed: 06/01/2023]
Abstract
Phages infecting Staphylococcus aureus can be used as therapeutics against antibiotic-resistant bacterial infections. However, there is limited information about the mechanism of genome delivery of phages that infect Gram-positive bacteria. Here, we present the structures of native S. aureus phage P68, genome ejection intermediate, and empty particle. The P68 head contains 72 subunits of inner core protein, 15 of which bind to and alter the structure of adjacent major capsid proteins and thus specify attachment sites for head fibers. Unlike in the previously studied phages, the head fibers of P68 enable its virion to position itself at the cell surface for genome delivery. The unique interaction of one end of P68 DNA with one of the 12 portal protein subunits is disrupted before the genome ejection. The inner core proteins are released together with the DNA and enable the translocation of phage genome across the bacterial membrane into the cytoplasm.
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Affiliation(s)
- Dominik Hrebík
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Dana Štveráková
- Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Karel Škubník
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Tibor Füzik
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Roman Pantůček
- Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Pavel Plevka
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
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24
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Xu J, Wang D, Gui M, Xiang Y. Structural assembly of the tailed bacteriophage ϕ29. Nat Commun 2019; 10:2366. [PMID: 31147544 PMCID: PMC6542822 DOI: 10.1038/s41467-019-10272-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 04/24/2019] [Indexed: 11/30/2022] Open
Abstract
The mature virion of the tailed bacteriophage ϕ29 is an ~33 MDa complex that contains more than 450 subunits of seven structural proteins assembling into a prolate head and a short non-contractile tail. Here, we report the near-atomic structures of the ϕ29 pre-genome packaging head (prohead), the mature virion and the genome-emptied virion. Structural comparisons suggest local rotation or oscillation of the head-tail connector upon DNA packaging and release. Termination of the DNA packaging occurs through pressure-dependent correlative positional and conformational changes in the connector. The funnel-shaped tail lower collar attaches the expanded narrow end of the connector and has a 180-Å long, 24-strand β barrel narrow stem tube that undergoes conformational changes upon genome release. The appendages form an interlocked assembly attaching the tail around the collar. The membrane active long loops at the distal end of the tail knob exit during the late stage of infection and form the cone-shaped tip of a largely hydrophobic helix barrel, prepared for membrane penetration. Mature particles of bacteriophage ϕ29 consist of a 33-MDa complex formed by over 450 subunits, assembled into a head and a short tail. Here, Xu et al. report the near-atomic structures of the ϕ29 prohead, the mature virion and the genome-emptied virion, providing insights into DNA packaging and release.
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Affiliation(s)
- Jingwei Xu
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Center for Infectious Disease Research, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, 100084, Beijing, China.,Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich, CH-8093, Zürich, Switzerland
| | - Dianhong Wang
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Center for Infectious Disease Research, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, 100084, Beijing, China
| | - Miao Gui
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Center for Infectious Disease Research, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, 100084, Beijing, China.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Ye Xiang
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Center for Infectious Disease Research, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, 100084, Beijing, China.
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25
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Ilca SL, Sun X, El Omari K, Kotecha A, de Haas F, DiMaio F, Grimes JM, Stuart DI, Poranen MM, Huiskonen JT. Multiple liquid crystalline geometries of highly compacted nucleic acid in a dsRNA virus. Nature 2019; 570:252-256. [DOI: 10.1038/s41586-019-1229-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 03/08/2019] [Indexed: 01/17/2023]
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Cryo-EM structures of herpes simplex virus type 1 portal vertex and packaged genome. Nature 2019; 570:257-261. [PMID: 31142842 PMCID: PMC6732574 DOI: 10.1038/s41586-019-1248-6] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 04/26/2019] [Indexed: 11/28/2022]
Abstract
Herpesviruses are enveloped viruses prevalent in the human population, responsible for a host of pathologies ranging from cold sores to birth defects and cancers. They are characterized by a highly pressurized, T (triangulation number) = 16 pseudo-icosahedral capsid encapsidating a tightly packed dsDNA genome1–3. A key process in the herpesvirus life cycle involves the recruitment of an ATP-driven terminase to a unique portal vertex to recognize, package, and cleave concatemeric dsDNA, ultimately giving rise to a pressurized, genome-containing virion4,5. Though this process has been studied in dsDNA phages6–9—with which herpesviruses bear some similarities—a lack of high-resolution in situ structures of genome-packaging machinery has prevented the elucidation of how these multi-step reactions, which require close coordination among multiple actors, occur in an integrated environment. Thus, to better define the structural basis of genome packaging and organization in the prototypical herpesvirus, herpes simplex virus type 1 (HSV-1), we developed sequential localized classification and symmetry relaxation methods to process cryoEM images of HSV-1 virions, enabling us to decouple and reconstruct hetero-symmetric and asymmetric elements within the pseudo-icosahedral capsid. Here we show in situ structures of the unique portal vertex, genomic termini, and ordered dsDNA coils in the capsid spooled around a disordered dsDNA core. We identify tentacle-like helices and a globular complex capping the portal vertex not observed in phages, indicative of adaptations in the DNA-packaging process specific to herpesviruses. Finally, our atomic models of portal vertex elements reveal how the five-fold-related capsid accommodates symmetry mismatch imparted by the dodecameric portal—long a mystery in icosahedral viruses—and inform possible DNA sequence-recognition and headful-sensing pathways involved in genome packaging. Our work represents the first fully symmetry-resolved structure of a portal vertex and first atomic model of a portal complex in a eukaryotic virus.
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Twarock R, Stockley PG. RNA-Mediated Virus Assembly: Mechanisms and Consequences for Viral Evolution and Therapy. Annu Rev Biophys 2019; 48:495-514. [PMID: 30951648 PMCID: PMC7612295 DOI: 10.1146/annurev-biophys-052118-115611] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Viruses, entities composed of nucleic acids, proteins, and in some cases lipids lack the ability to replicate outside their target cells. Their components self-assemble at the nanoscale with exquisite precision-a key to their biological success in infection. Recent advances in structure determination and the development of biophysical tools such as single-molecule spectroscopy and noncovalent mass spectrometry allow unprecedented access to the detailed assembly mechanisms of simple virions. Coupling these techniques with mathematical modeling and bioinformatics has uncovered a previously unsuspected role for genomic RNA in regulating formation of viral capsids, revealing multiple, dispersed RNA sequence/structure motifs [packaging signals (PSs)] that bind cognate coat proteins cooperatively. The PS ensemble controls assembly efficiency and accounts for the packaging specificity seen in vivo. The precise modes of action of the PSs vary between viral families, but this common principle applies across many viral families, including major human pathogens. These insights open up the opportunity to block or repurpose PS function in assembly for both novel antiviral therapy and gene/drug/vaccine applications.
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Affiliation(s)
- Reidun Twarock
- Departments of Mathematics and Biology, and York Cross-disciplinary Centre for Systems Analysis, University of York, York YO10 5GE, United Kingdom;
| | - Peter G Stockley
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom;
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28
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Abstract
The filamentous bacteriophage IKe is one of many nonenveloped bacterial viruses that encapsulate a circular single-stranded viral genome in the phage capsid shell. The shell of IKe is comprised of about 3,100 copies of the IKe major coat protein. Atomic-resolution structures of filamentous phages are scarce, and the structure of the single-stranded DNA is a matter of debate. Our cryo-electron microscopy structure of the filamentous bacteriophage IKe at a resolution of 3.4 Å provides atomic details on the structure of the major coat protein, the symmetry of the capsid shell, and the key interactions driving its assembly. We propose a model for the conformation of the circular single-stranded DNA core and the interactions between the capsid shell and inner DNA core. The filamentous bacteriophage IKe infects Escherichia coli cells bearing IncN pili. We report the cryo-electron microscopy structure of the micrometer-long IKe viral particle at a resolution of 3.4 Å. The major coat protein [protein 8 (p8)] consists of 47 residues that fold into a ∼68-Å-long helix. An atomic model of the coat protein was built. Five p8 helices in a horizontal layer form a pentamer, and symmetrically neighboring p8 layers form a right-handed helical cylinder having a rise per pentamer of 16.77 Å and a twist of 38.52°. The inner surface of the capsid cylinder is positively charged and has direct interactions with the encapsulated circular single-stranded DNA genome, which has an electron density consistent with an unusual left-handed helix structure. Similar to capsid structures of other filamentous viruses, strong capsid packing in the IKe particle is maintained by hydrophobic residues. Despite having a different length and large sequence differences from other filamentous phages, π–π interactions were found between Tyr9 of one p8 and Trp29 of a neighboring p8 in IKe that are similar to interactions observed in phage M13, suggesting that, despite sequence divergence, overall structural features are maintained.
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29
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Abstract
Flaviviruses assemble initially in an immature, noninfectious state and undergo extensive conformational rearrangements to generate mature virus. Previous cryo-electron microscopy (cryo-EM) structural studies of flaviviruses assumed icosahedral symmetry and showed the concentric organization of the external glycoprotein shell, the lipid membrane, and the internal nucleocapsid core. We show here that when icosahedral symmetry constraints were excluded in calculating the cryo-EM reconstruction of an immature flavivirus, the nucleocapsid core was positioned asymmetrically with respect to the glycoprotein shell. The core was positioned closer to the lipid membrane at the proximal pole, and at the distal pole, the outer glycoprotein spikes and inner membrane leaflet were either perturbed or missing. In contrast, in the asymmetric reconstruction of a mature flavivirus, the core was positioned concentric with the glycoprotein shell. The deviations from icosahedral symmetry demonstrated that the core and glycoproteins have varied interactions, which likely promotes viral assembly and budding.
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Prevelige PE, Cortines JR. Phage assembly and the special role of the portal protein. Curr Opin Virol 2018; 31:66-73. [PMID: 30274853 DOI: 10.1016/j.coviro.2018.09.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 08/16/2018] [Accepted: 09/21/2018] [Indexed: 12/18/2022]
Abstract
Virus infections are ultimately dependent on a successful viral genome delivery to the host cell. The bacteriophage family Caudovirales evolved specialized machinery that fulfills this function: the portal proteins complex. The complexes are arranged as dodecameric rings and are a structural part of capsids incorporated at a five-fold vertex. They are involved in crucial aspects of viral replication, such as virion assembly, DNA packaging and DNA delivery. This review focuses on the organization and the mechanism through which these portal complexes achieve viral genome delivery and their similarities to other viral portal complexes.
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Affiliation(s)
- Peter E Prevelige
- Department of Microbiology, University of Alabama at Birmingham, 35294, United States
| | - Juliana R Cortines
- Departamento de Virologia, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-902, Brazil.
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31
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Cao M, Wang Y, Zhao W, Qi R, Han Y, Wu R, Wang Y, Xu H. Peptide-Induced DNA Condensation into Virus-Mimicking Nanostructures. ACS APPLIED MATERIALS & INTERFACES 2018; 10:24349-24360. [PMID: 29979028 DOI: 10.1021/acsami.8b00246] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A series of surfactant-like peptides have been designed for inducing DNA condensation, which are all comprised of the same set of amino acids in different sequences. Results from experiments and molecular dynamics simulations show that the peptide's self-assembly and DNA-interaction behaviors can be well manipulated through sequence variation. With optimized pairing modes between the β-sheets, the peptide of I3V3A3G3K3 can induce efficient DNA condensation into virus-mimicking structures. The condensation involves two steps; the peptide molecules first bind onto the DNA chain through electrostatic interactions and then self-associate into β-sheets under hydrophobic interactions and hydrogen bonding. In such condensates, the peptide β-sheets act as scaffolds to assist the ordered arrangement of DNA, mimicking the very nature of the virus capsid in helping DNA packaging. Such a hierarchy affords an extremely stable structure to attain the highly condensed state and protect DNA against enzymatic degradation. Moreover, the condensate size can be well tuned by the DNA length. The condensates with smaller sizes and narrow size distribution can deliver DNA efficiently into cells. The study helps not only for probing into the DNA packaging mechanism in virus but also delineating the role of peptide self-assembly in DNA condensation, which may lead to development of peptide-based gene vectors for therapeutic applications.
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Affiliation(s)
- Meiwen Cao
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemical Engineering , China University of Petroleum (East China) , 66 Changjiang West Road , Qingdao 266580 , China
| | - Yu Wang
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemical Engineering , China University of Petroleum (East China) , 66 Changjiang West Road , Qingdao 266580 , China
| | - Wenjing Zhao
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemical Engineering , China University of Petroleum (East China) , 66 Changjiang West Road , Qingdao 266580 , China
| | - Ruilian Qi
- Key Laboratory of Colloid and Interface Science, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
| | - Yuchun Han
- Key Laboratory of Colloid and Interface Science, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
| | - Rongliang Wu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering , Donghua University , Shanghai 201620 , China
| | - Yilin Wang
- Key Laboratory of Colloid and Interface Science, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
| | - Hai Xu
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemical Engineering , China University of Petroleum (East China) , 66 Changjiang West Road , Qingdao 266580 , China
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32
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Image processing for cryogenic transmission electron microscopy of symmetry-mismatched complexes. Biosci Rep 2018; 38:BSR20170203. [PMID: 29439140 PMCID: PMC5857907 DOI: 10.1042/bsr20170203] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 02/05/2018] [Accepted: 02/05/2018] [Indexed: 12/23/2022] Open
Abstract
Cryogenic transmission electron microscopy (cryo-TEM) is a high-resolution biological imaging method, whereby biological samples, such as purified proteins, macromolecular complexes, viral particles, organelles and cells, are embedded in vitreous ice preserving their native structures. Due to sensitivity of biological materials to the electron beam of the microscope, only relatively low electron doses can be applied during imaging. As a result, the signal arising from the structure of interest is overpowered by noise in the images. To increase the signal-to-noise ratio, different image processing-based strategies that aim at coherent averaging of signal have been devised. In such strategies, images are generally assumed to arise from multiple identical copies of the structure. Prior to averaging, the images must be grouped according to the view of the structure they represent and images representing the same view must be simultaneously aligned relatively to each other. For computational reconstruction of the 3D structure, images must contain different views of the original structure. Structures with multiple symmetry-related substructures are advantageous in averaging approaches because each image provides multiple views of the substructures. However, the symmetry assumption may be valid for only parts of the structure, leading to incoherent averaging of the other parts. Several image processing approaches have been adapted to tackle symmetry-mismatched substructures with increasing success. Such structures are ubiquitous in nature and further computational method development is needed to understanding their biological functions.
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33
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Starostin EL, van der Heijden GHM. Forceless Sadowsky strips are spherical. Phys Rev E 2018; 97:023001. [PMID: 29548146 DOI: 10.1103/physreve.97.023001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Indexed: 11/07/2022]
Abstract
We show that thin rectangular ribbons, defined as energy-minimizing configurations of the Sadowsky functional for narrow developable elastic strips, have a propensity to form spherical shapes in the sense that forceless solutions lie on a sphere. This has implications for ribbonlike objects in (bio)polymer physics and nanoscience that cannot be described by the classical wormlike chain model. A wider class of functionals with this property is identified.
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Affiliation(s)
- E L Starostin
- Department of Civil, Environmental & Geomatic Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - G H M van der Heijden
- Department of Civil, Environmental & Geomatic Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom
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34
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Breaking Symmetry in Viral Icosahedral Capsids as Seen through the Lenses of X-ray Crystallography and Cryo-Electron Microscopy. Viruses 2018; 10:v10020067. [PMID: 29414851 PMCID: PMC5850374 DOI: 10.3390/v10020067] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 01/26/2018] [Accepted: 01/31/2018] [Indexed: 12/19/2022] Open
Abstract
The majority of viruses on Earth form capsids built by multiple copies of one or more types of a coat protein arranged with 532 symmetry, generating an icosahedral shell. This highly repetitive structure is ideal to closely pack identical protein subunits and to enclose the nucleic acid genomes. However, the icosahedral capsid is not merely a passive cage but undergoes dynamic events to promote packaging, maturation and the transfer of the viral genome into the host. These essential processes are often mediated by proteinaceous complexes that interrupt the shell’s icosahedral symmetry, providing a gateway through the capsid. In this review, we take an inventory of molecular structures observed either internally, or at the 5-fold vertices of icosahedral DNA viruses that infect bacteria, archea and eukaryotes. Taking advantage of the recent revolution in cryo-electron microscopy (cryo-EM) and building upon a wealth of crystallographic structures of individual components, we review the design principles of non-icosahedral structural components that interrupt icosahedral symmetry and discuss how these macromolecules play vital roles in genome packaging, ejection and host receptor-binding.
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35
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Abstract
Many icosahedral viruses use a specialized portal vertex for genome encapsidation in the viral capsid (or head). This structure then controls release of the viral genetic information to the host cell at the beginning of infection. In tailed bacteriophages, the portal system is connected to a tail device that delivers their genome to the bacterial cytoplasm. The head-to-tail interface is a multiprotein complex that locks the viral DNA inside the phage capsid correctly positioned for egress and that controls its ejection when the viral particle interacts with the host cell receptor. Here we review the molecular mechanisms how this interface is assembled and how it carries out those two critical steps in the life cycle of tailed phages.
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Affiliation(s)
- Paulo Tavares
- Department of Virology, Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France.
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36
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Atomic Structures of Minor Proteins VI and VII in Human Adenovirus. J Virol 2017; 91:JVI.00850-17. [PMID: 28978703 DOI: 10.1128/jvi.00850-17] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 09/15/2017] [Indexed: 12/31/2022] Open
Abstract
Human adenoviruses (Ad) are double-stranded DNA (dsDNA) viruses associated with infectious diseases, but they are better known as tools for gene delivery and oncolytic anticancer therapy. Atomic structures of Ad provide the basis for the development of antivirals and for engineering efforts toward more effective applications. Since 2010, atomic models of human Ad5 have been derived independently from photographic film cryo-electron microscopy (cryo-EM) and X-ray crystallography studies, but discrepancies exist concerning the assignment of cement proteins IIIa, VIII, and IX. To clarify these discrepancies, we employed the technology of direct electron counting to obtain a cryo-EM structure of human Ad5 at 3.2-Å resolution. Our improved structure unambiguously confirms our previous cryo-EM models of proteins IIIa, VIII, and IX and explains the likely cause of conflict in the crystallography models. The improved structure also allows the identification of three new components in the cavity of hexon-the cleaved N terminus of precursor protein VI (pVIn), the cleaved N terminus of precursor protein VII (pVIIn2), and mature protein VI. The binding of pVIIn2-and, by extension, that of genome-condensing pVII-to hexons is consistent with the previously proposed dsDNA genome-capsid coassembly for adenoviruses, which resembles that of single-stranded RNA (ssRNA) viruses but differs from the well-established mechanism of pumping dsDNA into a preformed protein capsid exemplified by tailed bacteriophages and herpesviruses.IMPORTANCE Adenovirus is a double-edged sword to humans: it is a widespread pathogen but can be used as a bioengineering tool for anticancer and gene therapies. The atomic structure of the virus provides the basis for antiviral and application developments, but conflicting atomic models for the important cement proteins IIIa, VIII, and IX from conventional/film cryo-EM and X-ray crystallography studies have caused confusion. Using cutting-edge cryo-EM technology with electron counting, we improved the structure of human adenovirus type 5 and confirmed our previous models of cement proteins IIIa, VIII, and IX, thus clarifying the inconsistent structures. The improved structure also reveals atomic details of membrane-lytic protein VI and genome-condensing protein VII and supports the previously proposed genome-capsid coassembly mechanism for adenoviruses.
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37
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Jiang W, Tang L. Atomic cryo-EM structures of viruses. Curr Opin Struct Biol 2017; 46:122-129. [PMID: 28787658 PMCID: PMC5683926 DOI: 10.1016/j.sbi.2017.07.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 07/12/2017] [Accepted: 07/19/2017] [Indexed: 01/30/2023]
Abstract
During the development of single particle cryo-EM in past five decades, icosahedral viruses have led the resolution progress owing to their large mass and high symmetry. Many technical advances in cryo-EM were first established with viruses. Since reaching ∼4Å resolution in 2008, it has become a relatively routine task to solve the atomic structure of isolated viruses. The future of structural virology will be increasingly focused on remaining challenges including solving structures of jumbo viruses, intermediate functional states during assembly, maturation, and infection, and in situ structures. Recent demonstrations of near-atomic resolution structure with electron tomography and sub-tomogram averaging opens a new direction for high resolution studies of pleomorphic viruses and the pleomorphic states of icosahedral viruses that have defied past efforts using the single particle cryo-EM approach.
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Affiliation(s)
- Wen Jiang
- Department of Biological Sciences, Immunology and Infectious Disease, Purdue University, 240 S. Martin Jischke Drive, West Lafayette, IN 47907, USA; Department of Chemistry, Immunology and Infectious Disease, Purdue University, 240 S. Martin Jischke Drive, West Lafayette, IN 47907, USA; Markey Center for Structural Biology, Immunology and Infectious Disease, Purdue University, 240 S. Martin Jischke Drive, West Lafayette, IN 47907, USA; Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, 240 S. Martin Jischke Drive, West Lafayette, IN 47907, USA.
| | - Liang Tang
- Department of Molecular Biosciences, University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA.
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38
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Abstract
Recently, dozens of virus structures have been solved to resolutions between 2.5 and 5.0 Å by means of electron cryomicroscopy. With these structures we are now firmly within the "atomic age" of electron cryomicroscopy, as these studies can reveal atomic details of protein and nucleic acid topology and interactions between specific residues. This improvement in resolution has been the result of direct electron detectors and image processing advances. Although enforcing symmetry facilitates reaching near-atomic resolution with fewer particle images, it unfortunately obscures some biologically interesting components of a virus. New approaches on relaxing symmetry and exploring structure dynamics and heterogeneity of viral assemblies have revealed important insights into genome packaging, virion assembly, cell entry, and other stages of the viral life cycle. In the future, novel methods will be required to reveal yet-unknown structural conformations of viruses, relevant to their biological activities. Ultimately, these results hold the promise of answering many unresolved questions linking structural diversity of viruses to their biological functions.
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Affiliation(s)
- Jason T Kaelber
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030.,National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Corey F Hryc
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030.,Graduate Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas 77030;
| | - Wah Chiu
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030.,National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030.,Graduate Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas 77030;
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39
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Myers CG, Pettitt BM. Phage-like packing structures with mean field sequence dependence. J Comput Chem 2017; 38:1191-1197. [PMID: 28349552 PMCID: PMC5403567 DOI: 10.1002/jcc.24727] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 11/30/2016] [Accepted: 12/01/2016] [Indexed: 11/08/2022]
Abstract
Packing of double-stranded DNA in phages must overcome both electrostatic repulsions and the problem of persistence length. We consider coarse-grained models with the ability to kink and with randomly generated disorder. We show that the introduction of kinking into configurations of the DNA polymer packaged within spherical confinement results in significant reductions of the overall energies and pressures. We use a kink model which has the ability to deform every 24 bp, close to the average length predicted from phage sequence. The introduction of such persistence length defects even with highly random packing models increases the local nematic ordering of the packed DNA polymer segments. Such local ordering allowed by kinking not only reduces the total bending energy of confined DNA due to nonlinear elasticity but also reduces the electrostatic component of the energy and pressure. We show that a broad ensemble of polymer configurations is consistent with the structural data. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Christopher G Myers
- Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas, 77030-3411
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas, 77555-0144
| | - B Montgomery Pettitt
- Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas, 77030-3411
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas, 77555-0144
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40
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Tu J, Park T, Morado DR, Hughes KT, Molineux IJ, Liu J. Dual host specificity of phage SP6 is facilitated by tailspike rotation. Virology 2017; 507:206-215. [PMID: 28456019 DOI: 10.1016/j.virol.2017.04.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 04/13/2017] [Accepted: 04/17/2017] [Indexed: 01/08/2023]
Abstract
Bacteriophage SP6 exhibits dual-host adsorption specificity. The SP6 tailspikes are recognized as important in host range determination but the mechanisms underlying dual host specificity are unknown. Cryo-electron tomography and sub-tomogram classification were used to analyze the SP6 virion with a particular focus on the interaction of tailspikes with host membranes. The SP6 tail is surrounded by six V-shaped structures that interconnect in forming a hand-over-hand hexameric garland. Each V-shaped structure consists of two trimeric tailspike proteins: gp46 and gp47, connected through the adaptor protein gp37. SP6 infection of Salmonella enterica serovars Typhimurium and Newport results in distinguishable changes in tailspike orientation, providing the first direct demonstration how tailspikes can confer dual host adsorption specificity. SP6 also infects S. Typhimurium strains lacking O antigen; in these infections tailspikes have no apparent specific role and the phage tail must therefore interact with a distinct host receptor to allow infection.
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Affiliation(s)
- Jiagang Tu
- Department of Pathology and Laboratory Medicine, McGovern Medical School at UTHealth, Houston, TX 77030, USA
| | - Taehyun Park
- Center for Infectious Disease, Department of Molecular Biosciences, Institute for Cell and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Dustin R Morado
- Department of Pathology and Laboratory Medicine, McGovern Medical School at UTHealth, Houston, TX 77030, USA
| | - Kelly T Hughes
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Ian J Molineux
- Center for Infectious Disease, Department of Molecular Biosciences, Institute for Cell and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA.
| | - Jun Liu
- Department of Pathology and Laboratory Medicine, McGovern Medical School at UTHealth, Houston, TX 77030, USA.
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41
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Portal protein functions akin to a DNA-sensor that couples genome-packaging to icosahedral capsid maturation. Nat Commun 2017; 8:14310. [PMID: 28134243 PMCID: PMC5290284 DOI: 10.1038/ncomms14310] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 12/14/2016] [Indexed: 11/24/2022] Open
Abstract
Tailed bacteriophages and herpesviruses assemble infectious particles via an empty precursor capsid (or ‘procapsid') built by multiple copies of coat and scaffolding protein and by one dodecameric portal protein. Genome packaging triggers rearrangement of the coat protein and release of scaffolding protein, resulting in dramatic procapsid lattice expansion. Here, we provide structural evidence that the portal protein of the bacteriophage P22 exists in two distinct dodecameric conformations: an asymmetric assembly in the procapsid (PC-portal) that is competent for high affinity binding to the large terminase packaging protein, and a symmetric ring in the mature virion (MV-portal) that has negligible affinity for the packaging motor. Modelling studies indicate the structure of PC-portal is incompatible with DNA coaxially spooled around the portal vertex, suggesting that newly packaged DNA triggers the switch from PC- to MV-conformation. Thus, we propose the signal for termination of ‘Headful Packaging' is a DNA-dependent symmetrization of portal protein. Tailed bacteriophages assemble empty precursor capsids known as procapsids that are subsequently filled with viral DNA by a genome-packaging motor. Here the authors present a structure-based analysis that suggests the signal for termination of genome packaging is achieved through a DNA-dependent symmetrization of portal protein.
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In situ structures of the genome and genome-delivery apparatus in a single-stranded RNA virus. Nature 2016; 541:112-116. [PMID: 27992877 PMCID: PMC5701785 DOI: 10.1038/nature20589] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 10/26/2016] [Indexed: 12/11/2022]
Abstract
Genome packaging into a protein capsid and its subsequent delivery into a host cell are two fundamental processes in the life cycle of a virus. Unlike dsDNA viruses which pump their genome into a preformed capsid1-3, ssRNA viruses, such as bacteriophage MS2, co-assemble their capsid with genome4-7; however, the structural basis of this co-assembly is poorly understood. MS2 infects Escherichia coli via host “sex” pilus (F-pilus)8 and is the first fully-sequenced organism9 and a model system for studies of gene translational regulations10,11, RNA-protein interactions12-14, and RNA virus assembly15-17. Its positive-sense ssRNA genome of 3569 bases is enclosed in a capsid with one maturation protein (MP) monomer and 89 coat protein (CP) dimers arranged in a T=3 icosahedral lattice18,19. MP is responsible for attaching the virus to an F-pilus and delivering the viral genome into the host during infection8, but how the genome is organized and delivered are not known. Here we show the MS2 structure at 3.6Å resolution determined by electron-counting cryo electron microscopy (cryoEM) and asymmetric reconstruction. We traced ~80% backbone of the viral genome, built atomic models for 16 RNA stem-loops, and identified three conserved motifs of RNA-CP interactions among 15 of these stem-loops with diverse sequences. The stem-loop at 3’ end of the genome interacts extensively with the MP, which, with just a six-helix bundle and a six-stranded β-sheet, forms a genome-delivery apparatus, and joins 89 CP-dimers to form a capsid. This first atomic description of genome-capsid interactions in a spherical ssRNA virus provides insights into genome delivery via host “sex” pilus and mechanisms underlying ssRNA-capsid co-assembly, and inspires imaginations about links between nucleoprotein complexes and the origin of viruses.
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Liu Z, Zhang J. Exploring the inside details of virions by electron microscopy. BIOPHYSICS REPORTS 2016; 2:21-24. [PMID: 27819027 PMCID: PMC5071365 DOI: 10.1007/s41048-016-0022-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 01/24/2016] [Indexed: 11/03/2022] Open
Affiliation(s)
- Zheng Liu
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032 USA
| | - Jingqiang Zhang
- College of Life Science, SunYat-sen University, Guangzhou, 510275 China
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Gorzelnik KV, Cui Z, Reed CA, Jakana J, Young R, Zhang J. Asymmetric cryo-EM structure of the canonical Allolevivirus Qβ reveals a single maturation protein and the genomic ssRNA in situ. Proc Natl Acad Sci U S A 2016; 113:11519-11524. [PMID: 27671640 PMCID: PMC5068298 DOI: 10.1073/pnas.1609482113] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Single-stranded (ss) RNA viruses infect all domains of life. To date, for most ssRNA virions, only the structures of the capsids and their associated protein components have been resolved to high resolution. Qβ, an ssRNA phage specific for the conjugative F-pilus, has a T = 3 icosahedral lattice of coat proteins assembled around its 4,217 nucleotides of genomic RNA (gRNA). In the mature virion, the maturation protein, A2, binds to the gRNA and is required for adsorption to the F-pilus. Here, we report the cryo-electron microscopy (cryo-EM) structures of Qβ with and without symmetry applied. The icosahedral structure, at 3.7-Å resolution, resolves loops not previously seen in the published X-ray structure, whereas the asymmetric structure, at 7-Å resolution, reveals A2 and the gRNA. A2 contains a bundle of α-helices and replaces one dimer of coat proteins at a twofold axis. The helix bundle binds gRNA, causing denser packing of RNA in its proximity, which asymmetrically expands the surrounding coat protein shell to potentially facilitate RNA release during infection. We observe a fixed pattern of gRNA organization among all viral particles, with the major and minor grooves of RNA helices clearly visible. A single layer of RNA directly contacts every copy of the coat protein, with one-third of the interactions occurring at operator-like RNA hairpins. These RNA-coat interactions stabilize the tertiary structure of gRNA within the virion, which could further provide a roadmap for capsid assembly.
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Affiliation(s)
- Karl V Gorzelnik
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843
| | - Zhicheng Cui
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843
| | - Catrina A Reed
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843
| | - Joanita Jakana
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030
| | - Ry Young
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843
| | - Junjie Zhang
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843;
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Zhou LQ, Yu WC, Chen YH, Luo KF. Ejection dynamics of semiflexible polymers out of a nanochannel. CHINESE JOURNAL OF POLYMER SCIENCE 2016. [DOI: 10.1007/s10118-016-1842-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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46
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Lee H, Shingler KL, Organtini LJ, Ashley RE, Makhov AM, Conway JF, Hafenstein S. The novel asymmetric entry intermediate of a picornavirus captured with nanodiscs. SCIENCE ADVANCES 2016; 2:e1501929. [PMID: 27574701 PMCID: PMC4996645 DOI: 10.1126/sciadv.1501929] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 07/28/2016] [Indexed: 06/06/2023]
Abstract
Many nonenveloped viruses engage host receptors that initiate capsid conformational changes necessary for genome release. Structural studies on the mechanisms of picornavirus entry have relied on in vitro approaches of virus incubated at high temperatures or with excess receptor molecules to trigger the entry intermediate or A-particle. We have induced the coxsackievirus B3 entry intermediate by triggering the virus with full-length receptors embedded in lipid bilayer nanodiscs. These asymmetrically formed A-particles were reconstructed using cryo-electron microscopy and a direct electron detector. These first high-resolution structures of a picornavirus entry intermediate captured at a membrane with and without imposing icosahedral symmetry (3.9 and 7.8 Å, respectively) revealed a novel A-particle that is markedly different from the classical A-particles. The asymmetric receptor binding triggers minimal global capsid expansion but marked local conformational changes at the site of receptor interaction. In addition, viral proteins extrude from the capsid only at the site of extensive protein remodeling adjacent to the nanodisc. Thus, the binding of the receptor triggers formation of a unique site in preparation for genome release.
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Affiliation(s)
- Hyunwook Lee
- The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Kristin L. Shingler
- The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | | | - Robert E. Ashley
- The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | | | - James F. Conway
- University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Susan Hafenstein
- The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
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Symmetry-mismatch reconstruction of genomes and associated proteins within icosahedral viruses using cryo-EM. BIOPHYSICS REPORTS 2016; 2:25-32. [PMID: 27819028 PMCID: PMC5071370 DOI: 10.1007/s41048-016-0024-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 04/18/2016] [Indexed: 11/24/2022] Open
Abstract
Although near-atomic resolutions have been routinely achieved for structural determination of many icosahedral viral capsids, structures of genomes and associated proteins within the capsids are still less characterized because the genome information is overlapped by the highly symmetric capsid information in the virus particle images. We recently developed a software package for symmetry-mismatch structural reconstruction and determined the structures of the genome and RNA polymerases within an icosahedral virus for the first time. Here, we describe the protocol used for this structural determination, which may facilitate structural biologists in investigating the structures of viral genome and associated proteins.
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48
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Waters JT, Kim HD, Gumbart JC, Lu XJ, Harvey SC. DNA Scrunching in the Packaging of Viral Genomes. J Phys Chem B 2016; 120:6200-7. [PMID: 27214211 DOI: 10.1021/acs.jpcb.6b02149] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The motors that drive double-stranded DNA (dsDNA) genomes into viral capsids are among the strongest of all biological motors for which forces have been measured, but it is not known how they generate force. We previously proposed that the DNA is not a passive substrate but that it plays an active role in force generation. This "scrunchworm hypothesis" holds that the motor proteins repeatedly dehydrate and rehydrate the DNA, which then undergoes cyclic shortening and lengthening motions. These are captured by a coupled protein-DNA grip-and-release cycle to rectify the motion and translocate the DNA into the capsid. In this study, we examined the interactions of dsDNA with the dodecameric connector protein of bacteriophage ϕ29, using molecular dynamics simulations on four different DNA sequences, starting from two different conformations (A-DNA and B-DNA). In all four simulations starting with the protein equilibrated with A-DNA in the channel, we observed transitions to a common, metastable, highly scrunched conformation, designated A*. This conformation is very similar to one recently reported by Kumar and Grubmüller in much longer MD simulations on B-DNA docked into the ϕ29 connector. These results are significant for four reasons. First, the scrunched conformations occur spontaneously, without requiring lever-like protein motions often believed to be necessary for DNA translocation. Second, the transition takes place within the connector, providing the location of the putative "dehydrator". Third, the protein has more contacts with one strand of the DNA than with the other; the former was identified in single-molecule laser tweezer experiments as the "load-bearing strand". Finally, the spontaneity of the DNA-protein interaction suggests that it may play a role in the initial docking of DNA in motors like that of T4 that can load and package any sequence.
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Affiliation(s)
- James T Waters
- School of Physics, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Harold D Kim
- School of Physics, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - James C Gumbart
- School of Physics, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Xiang-Jun Lu
- Department of Biological Sciences, Columbia University , New York, New York 10027, United States
| | - Stephen C Harvey
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
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Podgornik R, Aksoyoglu MA, Yasar S, Svenšek D, Parsegian VA. DNA Equation of State: In Vitro vs In Viro. J Phys Chem B 2016; 120:6051-60. [DOI: 10.1021/acs.jpcb.6b02017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rudolf Podgornik
- Department
of Physics, University of Massachusetts, Amherst, Massachusetts 01003, United States
- Department
of Theoretical Physics, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
- Department
of Physics, Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - M. Alphan Aksoyoglu
- Department
of Physics, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Selcuk Yasar
- Department
of Physics, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Daniel Svenšek
- Department
of Physics, Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - V. Adrian Parsegian
- Department
of Physics, University of Massachusetts, Amherst, Massachusetts 01003, United States
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50
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New Structural Insights into the Genome and Minor Capsid Proteins of BK Polyomavirus using Cryo-Electron Microscopy. Structure 2016; 24:528-536. [PMID: 26996963 PMCID: PMC4826271 DOI: 10.1016/j.str.2016.02.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 01/22/2016] [Accepted: 02/17/2016] [Indexed: 11/22/2022]
Abstract
BK polyomavirus is the causative agent of several diseases in transplant patients and the immunosuppressed. In order to better understand the structure and life cycle of BK, we produced infectious virions and VP1-only virus-like particles in cell culture, and determined their three-dimensional structures using cryo-electron microscopy (EM) and single-particle image processing. The resulting 7.6-Å resolution structure of BK and 9.1-Å resolution of the virus-like particles are the highest-resolution cryo-EM structures of any polyomavirus. These structures confirm that the architecture of the major structural protein components of these human polyomaviruses are similar to previous structures from other hosts, but give new insight into the location and role of the enigmatic minor structural proteins, VP2 and VP3. We also observe two shells of electron density, which we attribute to a structurally ordered part of the viral genome, and discrete contacts between this density and both VP1 and the minor capsid proteins.
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