351
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Analysis of the functional compatibility of SIV capsid sequences in the context of the FIV gag precursor. PLoS One 2017; 12:e0177297. [PMID: 28475623 PMCID: PMC5419655 DOI: 10.1371/journal.pone.0177297] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Accepted: 04/25/2017] [Indexed: 02/02/2023] Open
Abstract
The formation of immature lentiviral particles is dependent on the multimerization of the Gag polyprotein at the plasma membrane of the infected cells. One key player in the virus assembly process is the capsid (CA) domain of Gag, which establishes the protein-protein interactions that give rise to the hexagonal lattice of Gag molecules in the immature virion. To gain a better understanding of the functional equivalence between the CA proteins of simian and feline immunodeficiency viruses (SIV and FIV, respectively), we generated a series of chimeric FIV Gag proteins in which the CA-coding region was partially or totally replaced by its SIV counterpart. All the FIV Gag chimeras were found to be assembly-defective; however, all of them are able to interact with wild-type SIV Gag and be recruited into extracellular virus-like particles, regardless of the SIV CA sequences present in the chimeric FIV Gag. The results presented here markedly contrast with our previous findings showing that chimeric SIVs carrying FIV CA-derived sequences are assembly-competent. Overall, our data support the notion that although the SIV and FIV CA proteins share 51% amino acid sequence similarity and exhibit a similar organization, i.e., an N-terminal domain joined by a flexible linker to a C-terminal domain, their functional exchange between these different lentiviruses is strictly dependent on the context of the recipient Gag precursor.
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352
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Ronsard L, Ganguli N, Singh VK, Mohankumar K, Rai T, Sridharan S, Pajaniradje S, Kumar B, Rai D, Chaudhuri S, Coumar MS, Ramachandran VG, Banerjea AC. Impact of Genetic Variations in HIV-1 Tat on LTR-Mediated Transcription via TAR RNA Interaction. Front Microbiol 2017; 8:706. [PMID: 28484443 PMCID: PMC5399533 DOI: 10.3389/fmicb.2017.00706] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/05/2017] [Indexed: 01/10/2023] Open
Abstract
HIV-1 evades host defense through mutations and recombination events, generating numerous variants in an infected patient. These variants with an undiminished virulence can multiply rapidly in order to progress to AIDS. One of the targets to intervene in HIV-1 replication is the trans-activator of transcription (Tat), a major regulatory protein that transactivates the long terminal repeat promoter through its interaction with trans-activation response (TAR) RNA. In this study, HIV-1 infected patients (n = 120) from North India revealed Ser46Phe (20%) and Ser61Arg (2%) mutations in the Tat variants with a strong interaction toward TAR leading to enhanced transactivation activities. Molecular dynamics simulation data verified that the variants with this mutation had a higher binding affinity for TAR than both the wild-type Tat and other variants that lacked Ser46Phe and Ser61Arg. Other mutations in Tat conferred varying affinities for TAR interaction leading to differential transactivation abilities. This is the first report from North India with a clinical validation of CD4 counts to demonstrate the influence of Tat genetic variations affecting the stability of Tat and its interaction with TAR. This study highlights the co-evolution pattern of Tat and predominant nucleotides for Tat activity, facilitating the identification of genetic determinants for the attenuation of viral gene expression.
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Affiliation(s)
- Larance Ronsard
- Laboratory of Virology, National Institute of ImmunologyDelhi, India.,Department of Microbiology, University College of Medical Sciences and Guru Teg Bahadur HospitalDelhi, India
| | - Nilanjana Ganguli
- Laboratory of Virology, National Institute of ImmunologyDelhi, India
| | - Vivek K Singh
- Centre for Bioinformatics, School of Life Sciences, Pondicherry UniversityPondicherry, India
| | - Kumaravel Mohankumar
- Department of Biochemistry and Molecular Biology, Pondicherry UniversityPondicherry, India.,Department of Veterinary Physiology and Pharmacology, Texas A&M University, College StationTX, USA
| | - Tripti Rai
- Department of Gastroenterology and Human Nutrition, All India Institute of Medical SciencesDelhi, India
| | - Subhashree Sridharan
- Department of Biochemistry and Molecular Biology, Pondicherry UniversityPondicherry, India.,Department of Symptom Research, The University of Texas MD Anderson Cancer Center, HoustonTX, USA
| | - Sankar Pajaniradje
- Department of Biochemistry and Molecular Biology, Pondicherry UniversityPondicherry, India
| | - Binod Kumar
- Department of Microbiology and Immunology, Rosalind Franklin University of Medicine and Science, ChicagoIL, USA
| | - Devesh Rai
- Department of Microbiology, All India Institute of Medical SciencesDelhi, India
| | - Suhnrita Chaudhuri
- Department of Neurological Surgery, Northwestern University, ChicagoIL, USA
| | - Mohane S Coumar
- Centre for Bioinformatics, School of Life Sciences, Pondicherry UniversityPondicherry, India
| | | | - Akhil C Banerjea
- Laboratory of Virology, National Institute of ImmunologyDelhi, India
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353
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Ma W, Xu L, de Moura AF, Wu X, Kuang H, Xu C, Kotov NA. Chiral Inorganic Nanostructures. Chem Rev 2017; 117:8041-8093. [DOI: 10.1021/acs.chemrev.6b00755] [Citation(s) in RCA: 485] [Impact Index Per Article: 69.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
| | | | - André F. de Moura
- Department
of Chemistry, Federal University of São Carlos, CP 676, CEP 13.565-905, São Carlos, SP, Brazil
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354
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Inhibition of HIV-1 Maturation via Small-Molecule Targeting of the Amino-Terminal Domain in the Viral Capsid Protein. J Virol 2017; 91:JVI.02155-16. [PMID: 28202766 DOI: 10.1128/jvi.02155-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 02/09/2017] [Indexed: 11/20/2022] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) capsid protein is an attractive therapeutic target, owing to its multifunctionality in virus replication and the high fitness cost of amino acid substitutions in capsids to HIV-1 infectivity. To date, small-molecule inhibitors have been identified that inhibit HIV-1 capsid assembly and/or impair its function in target cells. Here, we describe the mechanism of action of the previously reported capsid-targeting HIV-1 inhibitor, Boehringer-Ingelheim compound 1 (C1). We show that C1 acts during HIV-1 maturation to prevent assembly of a mature viral capsid. However, unlike the maturation inhibitor bevirimat, C1 did not significantly affect the kinetics or fidelity of Gag processing. HIV-1 particles produced in the presence of C1 contained unstable capsids that lacked associated electron density and exhibited impairments in early postentry stages of infection, most notably reverse transcription. C1 inhibited assembly of recombinant HIV-1 CA in vitro and induced aberrant cross-links in mutant HIV-1 particles capable of spontaneous intersubunit disulfide bonds at the interhexamer interface in the capsid lattice. Resistance to C1 was conferred by a single amino acid substitution within the compound-binding site in the N-terminal domain of the CA protein. Our results demonstrate that the binding site for C1 represents a new pharmacological vulnerability in the capsid assembly stage of the HIV-1 life cycle.IMPORTANCE The HIV-1 capsid protein is an attractive but unexploited target for clinical drug development. Prior studies have identified HIV-1 capsid-targeting compounds that display different mechanisms of action, which in part reflects the requirement for capsid function at both the efferent and afferent phases of viral replication. Here, we show that one such compound, compound 1, interferes with assembly of the conical viral capsid during virion maturation and results in perturbations at a specific protein-protein interface in the capsid lattice. We also identify and characterize a mutation in the capsid protein that confers resistance to the inhibitor. This study reveals a novel mechanism by which a capsid-targeting small molecule can inhibit HIV-1 replication.
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355
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Cuniasse P, Tavares P, Orlova EV, Zinn-Justin S. Structures of biomolecular complexes by combination of NMR and cryoEM methods. Curr Opin Struct Biol 2017; 43:104-113. [DOI: 10.1016/j.sbi.2016.12.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 11/08/2016] [Accepted: 12/13/2016] [Indexed: 11/28/2022]
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356
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Heddle JG, Chakraborti S, Iwasaki K. Natural and artificial protein cages: design, structure and therapeutic applications. Curr Opin Struct Biol 2017; 43:148-155. [DOI: 10.1016/j.sbi.2017.03.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 02/21/2017] [Accepted: 03/09/2017] [Indexed: 01/28/2023]
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357
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Valasatava Y, Bradley AR, Rose AS, Duarte JM, Prlić A, Rose PW. Towards an efficient compression of 3D coordinates of macromolecular structures. PLoS One 2017; 12:e0174846. [PMID: 28362865 PMCID: PMC5376293 DOI: 10.1371/journal.pone.0174846] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 03/16/2017] [Indexed: 11/18/2022] Open
Abstract
The size and complexity of 3D macromolecular structures available in the Protein Data Bank is constantly growing. Current tools and file formats have reached limits of scalability. New compression approaches are required to support the visualization of large molecular complexes and enable new and scalable means for data analysis. We evaluated a series of compression techniques for coordinates of 3D macromolecular structures and identified the best performing approaches. By balancing compression efficiency in terms of the decompression speed and compression ratio, and code complexity, our results provide the foundation for a novel standard to represent macromolecular coordinates in a compact and useful file format.
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Affiliation(s)
- Yana Valasatava
- Structural Bioinformatics Laboratory, San Diego Supercomputer Center, University of California, San Diego, La Jolla, CA, United States of America
| | - Anthony R Bradley
- Structural Bioinformatics Laboratory, San Diego Supercomputer Center, University of California, San Diego, La Jolla, CA, United States of America.,RCSB Protein Data Bank, San Diego Supercomputer Center, University of California, San Diego, La Jolla, CA, United States of America
| | - Alexander S Rose
- Structural Bioinformatics Laboratory, San Diego Supercomputer Center, University of California, San Diego, La Jolla, CA, United States of America
| | - Jose M Duarte
- Structural Bioinformatics Laboratory, San Diego Supercomputer Center, University of California, San Diego, La Jolla, CA, United States of America.,RCSB Protein Data Bank, San Diego Supercomputer Center, University of California, San Diego, La Jolla, CA, United States of America
| | - Andreas Prlić
- Structural Bioinformatics Laboratory, San Diego Supercomputer Center, University of California, San Diego, La Jolla, CA, United States of America.,RCSB Protein Data Bank, San Diego Supercomputer Center, University of California, San Diego, La Jolla, CA, United States of America
| | - Peter W Rose
- Structural Bioinformatics Laboratory, San Diego Supercomputer Center, University of California, San Diego, La Jolla, CA, United States of America.,RCSB Protein Data Bank, San Diego Supercomputer Center, University of California, San Diego, La Jolla, CA, United States of America
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358
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Computational On-Chip Imaging of Nanoparticles and Biomolecules using Ultraviolet Light. Sci Rep 2017; 7:44157. [PMID: 28276489 PMCID: PMC5343455 DOI: 10.1038/srep44157] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 02/02/2017] [Indexed: 12/28/2022] Open
Abstract
Significant progress in characterization of nanoparticles and biomolecules was enabled by the development of advanced imaging equipment with extreme spatial-resolution and sensitivity. To perform some of these analyses outside of well-resourced laboratories, it is necessary to create robust and cost-effective alternatives to existing high-end laboratory-bound imaging and sensing equipment. Towards this aim, we have designed a holographic on-chip microscope operating at an ultraviolet illumination wavelength (UV) of 266 nm. The increased forward scattering from nanoscale objects at this short wavelength has enabled us to detect individual sub-30 nm nanoparticles over a large field-of-view of >16 mm2 using an on-chip imaging platform, where the sample is placed at ≤0.5 mm away from the active area of an opto-electronic sensor-array, without any lenses in between. The strong absorption of this UV wavelength by biomolecules including nucleic acids and proteins has further enabled high-contrast imaging of nanoscopic aggregates of biomolecules, e.g., of enzyme Cu/Zn-superoxide dismutase, abnormal aggregation of which is linked to amyotrophic lateral sclerosis (ALS) - a fatal neurodegenerative disease. This UV-based wide-field computational imaging platform could be valuable for numerous applications in biomedical sciences and environmental monitoring, including disease diagnostics, viral load measurements as well as air- and water-quality assessment.
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359
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Koehl P, Poitevin F, Navaza R, Delarue M. The Renormalization Group and Its Applications to Generating Coarse-Grained Models of Large Biological Molecular Systems. J Chem Theory Comput 2017; 13:1424-1438. [PMID: 28170254 DOI: 10.1021/acs.jctc.6b01136] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Understanding the dynamics of biomolecules is the key to understanding their biological activities. Computational methods ranging from all-atom molecular dynamics simulations to coarse-grained normal-mode analyses based on simplified elastic networks provide a general framework to studying these dynamics. Despite recent successes in studying very large systems with up to a 100,000,000 atoms, those methods are currently limited to studying small- to medium-sized molecular systems due to computational limitations. One solution to circumvent these limitations is to reduce the size of the system under study. In this paper, we argue that coarse-graining, the standard approach to such size reduction, must define a hierarchy of models of decreasing sizes that are consistent with each other, i.e., that each model contains the information of the dynamics of its predecessor. We propose a new method, Decimate, for generating such a hierarchy within the context of elastic networks for normal-mode analysis. This method is based on the concept of the renormalization group developed in statistical physics. We highlight the details of its implementation, with a special focus on its scalability to large systems of up to millions of atoms. We illustrate its application on two large systems, the capsid of a virus and the ribosome translation complex. We show that highly decimated representations of those systems, containing down to 1% of their original number of atoms, still capture qualitatively and quantitatively their dynamics. Decimate is available as an OpenSource resource.
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Affiliation(s)
- Patrice Koehl
- Department of Computer Sciences and Genome Center, University of California, Davis , Davis, California 95616, United States
| | - Frédéric Poitevin
- Department of Structural Biology, Stanford University , Stanford, California 94305, United States.,Stanford PULSE Institute, SLAC National Accelerator Laboratory, Standford University , Menlo Park, California 94025, United States
| | - Rafael Navaza
- Platform of Crystallogenesis and Crystallography, CiTech, Institut Pasteur , 75015 Paris, France
| | - Marc Delarue
- Unité de Dynamique Structurale des Macromolécules, UMR 3528 du CNRS, Institut Pasteur , 75015 Paris, France
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360
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Perilla JR, Zhao G, Lu M, Ning J, Hou G, Byeon IJL, Gronenborn AM, Polenova T, Zhang P. CryoEM Structure Refinement by Integrating NMR Chemical Shifts with Molecular Dynamics Simulations. J Phys Chem B 2017; 121:3853-3863. [PMID: 28181439 DOI: 10.1021/acs.jpcb.6b13105] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Single particle cryoEM has emerged as a powerful method for structure determination of proteins and complexes, complementing X-ray crystallography and NMR spectroscopy. Yet, for many systems, the resolution of cryoEM density map has been limited to 4-6 Å, which only allows for resolving bulky amino acids side chains, thus hindering accurate model building from the density map. On the other hand, experimental chemical shifts (CS) from solution and solid state MAS NMR spectra provide atomic level data for each amino acid within a molecule or a complex; however, structure determination of large complexes and assemblies based on NMR data alone remains challenging. Here, we present a novel integrated strategy to combine the highly complementary experimental data from cryoEM and NMR computationally by molecular dynamics simulations to derive an atomistic model, which is not attainable by either approach alone. We use the HIV-1 capsid protein (CA) C-terminal domain as well as the large capsid assembly to demonstrate the feasibility of this approach, termed NMR CS-biased cryoEM structure refinement.
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Affiliation(s)
- Juan R Perilla
- Department of Physics and Beckman Institute, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Gongpu Zhao
- Department of Structural Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States.,Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States
| | - Manman Lu
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States.,Department of Chemistry and Biochemistry, University of Delaware , Newark, Delaware 19716, United States
| | - Jiying Ning
- Department of Structural Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States.,Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States
| | - Guangjin Hou
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States.,Department of Chemistry and Biochemistry, University of Delaware , Newark, Delaware 19716, United States
| | - In-Ja L Byeon
- Department of Structural Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States.,Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States
| | - Angela M Gronenborn
- Department of Structural Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States.,Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States
| | - Tatyana Polenova
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States.,Department of Chemistry and Biochemistry, University of Delaware , Newark, Delaware 19716, United States
| | - Peijun Zhang
- Department of Structural Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States.,Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States.,Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine , Headington, Oxford OX3 7BN, U.K.,Electron Bio-Imaging Centre, Diamond Light Sources, Harwell Science and Innovation Campus , Didcot OX11 0DE, U.K
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361
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Tarasova E, Farafonov V, Khayat R, Okimoto N, Komatsu TS, Taiji M, Nerukh D. All-Atom Molecular Dynamics Simulations of Entire Virus Capsid Reveal the Role of Ion Distribution in Capsid's Stability. J Phys Chem Lett 2017; 8:779-784. [PMID: 28129688 PMCID: PMC5391438 DOI: 10.1021/acs.jpclett.6b02759] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Present experimental methods do not have sufficient resolution to investigate all processes in virus particles at atomistic details. We report the results of molecular dynamics simulations and analyze the connection between the number of ions inside an empty capsid of PCV2 virus and its stability. We compare the crystallographic structures of the capsids with unresolved N-termini and without them in realistic conditions (room temperature and aqueous solution) and show that the structure is preserved. We find that the chloride ions play a key role in the stability of the capsid. A low number of chloride ions results in loss of the native icosahedral symmetry, while an optimal number of chloride ions create a neutralizing layer next to the positively charged inner surface of the capsid. Understanding the dependence of the capsid stability on the distribution of the ions will help clarify the details of the viral life cycle that is ultimately connected to the role of packaged viral genome inside the capsid.
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Affiliation(s)
- Elvira Tarasova
- Immanuel Kant Baltic Federal University, A. Nevskogo Street 14, Kaliningrad, 236041, Russian Federation
| | - Vladimir Farafonov
- Department of Physical Chemistry, V.N. Karazin Kharkiv National University, Svobody Square 4, Kharkiv, 61022, Ukraine
| | - Reza Khayat
- Department of Chemistry and Biochemistry, City College of New York, New York, New York 10031, United States
| | - Noriaki Okimoto
- Laboratory for Computational Molecular Design, Computational Biology Research Core, RIKEN Quantitative Biology Center (QBiC), QBiC Building B, 6-2-4 Furuedai, Suita, Osaka 565-0874, Japan
| | - Teruhisa S. Komatsu
- Laboratory for Computational Molecular Design, Computational Biology Research Core, RIKEN Quantitative Biology Center (QBiC), QBiC Building B, 6-2-4 Furuedai, Suita, Osaka 565-0874, Japan
| | - Makoto Taiji
- Laboratory for Computational Molecular Design, Computational Biology Research Core, RIKEN Quantitative Biology Center (QBiC), QBiC Building B, 6-2-4 Furuedai, Suita, Osaka 565-0874, Japan
| | - Dmitry Nerukh
- Systems Analytics Research Institute, Aston University, Birmingham, B4 7ET, United Kingdom
- Corresponding Author:
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362
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Particle sizing methods for the detection of protein aggregates in biopharmaceuticals. Bioanalysis 2017; 9:313-326. [DOI: 10.4155/bio-2016-0269] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Protein aggregation is a common biological phenomenon which is responsible for degenerative diseases and is problematic in the pharmaceutical industry. According to the rules provided by regulatory agencies, industry is supposed to assess the product quality regarding the presence of subvisible particles. Also, they should evaluate the technologies that are used to measure these particles. Therefore, US FDA and industry have been looking for methods capable of accurately characterizing the protein products. Four sizing techniques reviewed here are good candidates to be used for characterization of protein and their aggregates: dynamic light scattering, size-exclusion chromatography, electron microscopy and Taylor dispersion analysis. The first three are more established techniques while the last one is a more recent and growing technique.
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363
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Jeon J, Qiao X, Hung I, Mitra AK, Desfosses A, Huang D, Gor’kov PL, Craven RC, Kingston RL, Gan Z, Zhu F, Chen B. Structural Model of the Tubular Assembly of the Rous Sarcoma Virus Capsid Protein. J Am Chem Soc 2017; 139:2006-2013. [DOI: 10.1021/jacs.6b11939] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Jaekyun Jeon
- Department
of Physics, University of Central Florida, Orlando, Florida 32816, United States
| | - Xin Qiao
- Department
of Physics, University of Central Florida, Orlando, Florida 32816, United States
| | - Ivan Hung
- National
High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Alok K. Mitra
- School
of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Ambroise Desfosses
- School
of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Daniel Huang
- Department
of Physics, University of Central Florida, Orlando, Florida 32816, United States
| | - Peter L. Gor’kov
- National
High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Rebecca C. Craven
- Department
of Microbiology and Immunology, Penn State University College of Medicine, Hershey, Pennsylvania 17033, United States
| | - Richard L. Kingston
- School
of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Zhehong Gan
- National
High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Fangqiang Zhu
- Department
of Physics, Indiana University−Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - Bo Chen
- Department
of Physics, University of Central Florida, Orlando, Florida 32816, United States
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364
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Kwong PD, Chuang G, DeKosky BJ, Gindin T, Georgiev IS, Lemmin T, Schramm CA, Sheng Z, Soto C, Yang A, Mascola JR, Shapiro L. Antibodyomics: bioinformatics technologies for understanding B-cell immunity to HIV-1. Immunol Rev 2017; 275:108-128. [PMID: 28133812 PMCID: PMC5516196 DOI: 10.1111/imr.12480] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Numerous antibodies have been identified from HIV-1-infected donors that neutralize diverse strains of HIV-1. These antibodies may provide the basis for a B cell-mediated HIV-1 vaccine. However, it has been unclear how to elicit similar antibodies by vaccination. To address this issue, we have undertaken an informatics-based approach to understand the genetic and immunologic processes controlling the development of HIV-1-neutralizing antibodies. As DNA sequencing comprises the fastest growing database of biological information, we focused on incorporating next-generation sequencing of B-cell transcripts to determine the origin, maturation pathway, and prevalence of broadly neutralizing antibody lineages (Antibodyomics1, 2, 4, and 6). We also incorporated large-scale robotic analyses of serum neutralization to identify and quantify neutralizing antibodies in donor cohorts (Antibodyomics3). Statistical analyses furnish another layer of insight (Antibodyomics5), with physical characteristics of antibodies and their targets through molecular dynamics simulations (Antibodyomics7) and free energy perturbation analyses (Antibodyomics8) providing information-rich output. Functional interrogation of individual antibodies (Antibodyomics9) and synthetic antibody libraries (Antibodyomics10) also yields multi-dimensional data by which to understand and improve antibodies. Antibodyomics, described here, thus comprise resolution-enhancing tools, which collectively embody an information-driven discovery engine aimed toward the development of effective B cell-based vaccines.
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Affiliation(s)
- Peter D. Kwong
- Vaccine Research CenterNational Institute of Allergy and Infectious DiseasesNational Institutes of HealthBethesdaMDUSA
- Department of Biochemistry & Molecular BiophysicsColumbia UniversityNew YorkNYUSA
| | - Gwo‐Yu Chuang
- Vaccine Research CenterNational Institute of Allergy and Infectious DiseasesNational Institutes of HealthBethesdaMDUSA
| | - Brandon J. DeKosky
- Vaccine Research CenterNational Institute of Allergy and Infectious DiseasesNational Institutes of HealthBethesdaMDUSA
| | - Tatyana Gindin
- Department of Biochemistry & Molecular BiophysicsColumbia UniversityNew YorkNYUSA
| | - Ivelin S. Georgiev
- Vanderbilt Vaccine Center and Department of Pathology, Microbiology, and ImmunologyVanderbilt University Medical CenterNashvilleTNUSA
| | - Thomas Lemmin
- Department of Pharmaceutical ChemistryUniversity of California San FranciscoSan FranciscoCAUSA
| | - Chaim A. Schramm
- Vaccine Research CenterNational Institute of Allergy and Infectious DiseasesNational Institutes of HealthBethesdaMDUSA
- Department of Biochemistry & Molecular BiophysicsColumbia UniversityNew YorkNYUSA
- Department of Systems BiologyColumbia UniversityNew YorkNYUSA
| | - Zizhang Sheng
- Department of Biochemistry & Molecular BiophysicsColumbia UniversityNew YorkNYUSA
- Department of Systems BiologyColumbia UniversityNew YorkNYUSA
| | - Cinque Soto
- Vaccine Research CenterNational Institute of Allergy and Infectious DiseasesNational Institutes of HealthBethesdaMDUSA
| | - An‐Suei Yang
- Genomics Research CenterAcademia SinicaTaipeiTaiwan
| | - John R. Mascola
- Vaccine Research CenterNational Institute of Allergy and Infectious DiseasesNational Institutes of HealthBethesdaMDUSA
| | - Lawrence Shapiro
- Vaccine Research CenterNational Institute of Allergy and Infectious DiseasesNational Institutes of HealthBethesdaMDUSA
- Department of Biochemistry & Molecular BiophysicsColumbia UniversityNew YorkNYUSA
- Department of Systems BiologyColumbia UniversityNew YorkNYUSA
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365
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Quinn CM, Polenova T. Structural biology of supramolecular assemblies by magic-angle spinning NMR spectroscopy. Q Rev Biophys 2017; 50:e1. [PMID: 28093096 PMCID: PMC5483179 DOI: 10.1017/s0033583516000159] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In recent years, exciting developments in instrument technology and experimental methodology have advanced the field of magic-angle spinning (MAS) nuclear magnetic resonance (NMR) to new heights. Contemporary MAS NMR yields atomic-level insights into structure and dynamics of an astounding range of biological systems, many of which cannot be studied by other methods. With the advent of fast MAS, proton detection, and novel pulse sequences, large supramolecular assemblies, such as cytoskeletal proteins and intact viruses, are now accessible for detailed analysis. In this review, we will discuss the current MAS NMR methodologies that enable characterization of complex biomolecular systems and will present examples of applications to several classes of assemblies comprising bacterial and mammalian cytoskeleton as well as human immunodeficiency virus 1 and bacteriophage viruses. The body of work reviewed herein is representative of the recent advancements in the field, with respect to the complexity of the systems studied, the quality of the data, and the significance to the biology.
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Affiliation(s)
- Caitlin M. Quinn
- University of Delaware, Department of Chemistry and Biochemistry, Newark, DE 19711; Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, PA 15306
| | - Tatyana Polenova
- University of Delaware, Department of Chemistry and Biochemistry, Newark, DE 19711; Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, PA 15306
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366
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Abstract
Molecular dynamics (MD) simulations have been used as one of the main research tools to study a wide range of biological systems and bridge the gap between X-ray crystallography or NMR structures and biological mechanism. In the field of RNA nanostructures, MD simulations have been used to fix steric clashes in computationally designed RNA nanostructures, characterize the dynamics, and investigate the interaction between RNA and other biomolecules such as delivery agents and membranes.In this chapter we present examples of computational protocols for molecular dynamics simulations in explicit and implicit solvent using the Amber Molecular Dynamics Package. We also show examples of post-simulation analysis steps and briefly mention selected tools beyond the Amber package. Limitations of the methods, tools, and protocols are also discussed. Most of the examples are illustrated for a small RNA duplex (helix), but the protocols are applicable to any nucleic acid structure, subject only to the computational speed and memory limitations of the hardware available to the user.
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Affiliation(s)
- Taejin Kim
- Department of Chemistry, New York University, 10th Floor Silver Center, 100 Washington Square East, New York, NY, 10003, USA
| | - Wojciech K Kasprzak
- Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA
| | - Bruce A Shapiro
- RNA Structure and Design Section, RNA Biology Laboratory, National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA.
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367
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Holec AD, Mandal S, Prathipati PK, Destache CJ. Nucleotide Reverse Transcriptase Inhibitors: A Thorough Review, Present Status and Future Perspective as HIV Therapeutics. Curr HIV Res 2017; 15:411-421. [PMID: 29165087 PMCID: PMC7219633 DOI: 10.2174/1570162x15666171120110145] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 11/02/2017] [Accepted: 11/15/2017] [Indexed: 12/14/2022]
Abstract
BACKGROUND Human immunodeficiency virus type-1 (HIV-1) infection leads to acquired immunodeficiency syndrome (AIDS), a severe viral infection that has claimed approximately 658,507 lives in the US between the years 2010-2014. Antiretroviral (ARV) therapy has proven to inhibit HIV-1, but unlike other viral illness, not cure the infection. OBJECTIVE Among various Food and Drug Administration (FDA)-approved ARVs, nucleoside/ nucleotide reverse transcriptase inhibitors (NRTIs) are most effective in limiting HIV-1 infection. This review focuses on NRTIs mechanism of action and metabolism. METHODS A search of PubMed (1982-2016) was performed to capture relevant articles regarding NRTI pharmacology. RESULTS The current classical NRTIs pharmacology for HIV-1 prevention and treatment are presented. Finally, various novel strategies are proposed to improve the efficacy of NRTIs, which will increase therapeutic efficiency of present-day HIV-1 prevention/treatment regimen. CONCLUSION Use of NRTIs will continue to be critical for successful treatment and prevention of HIV-1.
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Affiliation(s)
- Ashley D. Holec
- Creighton University Medical Microbiology and Immunology, Omaha, NE, USA
| | - Subhra Mandal
- Creighton University School of Pharmacy & Health Professions, Omaha, NE, USA
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368
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Rychkov GN, Ilatovskiy AV, Nazarov IB, Shvetsov AV, Lebedev DV, Konev AY, Isaev-Ivanov VV, Onufriev AV. Partially Assembled Nucleosome Structures at Atomic Detail. Biophys J 2016; 112:460-472. [PMID: 28038734 DOI: 10.1016/j.bpj.2016.10.041] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 10/06/2016] [Accepted: 10/28/2016] [Indexed: 11/29/2022] Open
Abstract
The evidence is now overwhelming that partially assembled nucleosome states (PANS) are as important as the canonical nucleosome structure for the understanding of how accessibility to genomic DNA is regulated in cells. We use a combination of molecular dynamics simulation and atomic force microscopy to deliver, in atomic detail, structural models of three key PANS: the hexasome (H2A·H2B)·(H3·H4)2, the tetrasome (H3·H4)2, and the disome (H3·H4). Despite fluctuations of the conformation of the free DNA in these structures, regions of protected DNA in close contact with the histone core remain stable, thus establishing the basis for the understanding of the role of PANS in DNA accessibility regulation. On average, the length of protected DNA in each structure is roughly 18 basepairs per histone protein. Atomistically detailed PANS are used to explain experimental observations; specifically, we discuss interpretation of atomic force microscopy, Förster resonance energy transfer, and small-angle x-ray scattering data obtained under conditions when PANS are expected to exist. Further, we suggest an alternative interpretation of a recent genome-wide study of DNA protection in active chromatin of fruit fly, leading to a conclusion that the three PANS are present in actively transcribing regions in a substantial amount. The presence of PANS may not only be a consequence, but also a prerequisite for fast transcription in vivo.
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Affiliation(s)
- Georgy N Rychkov
- Division of Molecular and Radiation Biophysics, B.P. Konstantinov Petersburg Nuclear Physics Institute, National Research Center "Kurchatov Institute", Orlova Roscha, Gatchina, Leningrad District, Russia; Institute of Physics, Nanotechnology and Telecommunications, NRU Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
| | - Andrey V Ilatovskiy
- Division of Molecular and Radiation Biophysics, B.P. Konstantinov Petersburg Nuclear Physics Institute, National Research Center "Kurchatov Institute", Orlova Roscha, Gatchina, Leningrad District, Russia; Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California
| | - Igor B Nazarov
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia
| | - Alexey V Shvetsov
- Division of Molecular and Radiation Biophysics, B.P. Konstantinov Petersburg Nuclear Physics Institute, National Research Center "Kurchatov Institute", Orlova Roscha, Gatchina, Leningrad District, Russia; Institute of Applied Mathematics and Mechanics, NRU Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
| | - Dmitry V Lebedev
- Division of Molecular and Radiation Biophysics, B.P. Konstantinov Petersburg Nuclear Physics Institute, National Research Center "Kurchatov Institute", Orlova Roscha, Gatchina, Leningrad District, Russia
| | - Alexander Y Konev
- Division of Molecular and Radiation Biophysics, B.P. Konstantinov Petersburg Nuclear Physics Institute, National Research Center "Kurchatov Institute", Orlova Roscha, Gatchina, Leningrad District, Russia
| | - Vladimir V Isaev-Ivanov
- Division of Molecular and Radiation Biophysics, B.P. Konstantinov Petersburg Nuclear Physics Institute, National Research Center "Kurchatov Institute", Orlova Roscha, Gatchina, Leningrad District, Russia
| | - Alexey V Onufriev
- Departments of Computer Science and Physics, Virginia Tech, Blacksburg, Virginia.
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369
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Qi Y, Lee J, Singharoy A, McGreevy R, Schulten K, Im W. CHARMM-GUI MDFF/xMDFF Utilizer for Molecular Dynamics Flexible Fitting Simulations in Various Environments. J Phys Chem B 2016; 121:3718-3723. [PMID: 27936734 DOI: 10.1021/acs.jpcb.6b10568] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
X-ray crystallography and cryo-electron microscopy are two popular methods for the structure determination of biological molecules. Atomic structures are derived through the fitting and refinement of an initial model into electron density maps constructed by both experiments. Two computational approaches, MDFF and xMDFF, have been developed to facilitate this process by integrating the experimental data with molecular dynamics simulation. However, the setup of an MDFF/xMDFF simulation requires knowledge of both experimental and computational methods, which is not straightforward for nonexpert users. In addition, sometimes it is desirable to include realistic environments, such as explicit solvent and lipid bilayers during the simulation, which poses another challenge even for expert users. To alleviate these difficulties, we have developed MDFF/xMDFF Utilizer in CHARMM-GUI that helps users to set up an MDFF/xMDFF simulation. The capability of MDFF/xMDFF Utilizer is greatly enhanced by integration with other CHARMM-GUI modules, including protein structure manipulation, a diverse set of lipid types, and all-atom CHARMM and coarse-grained PACE force fields. With this integration, various simulation environments are available for MDFF Utilizer (vacuum, implicit/explicit solvent, and bilayers) and xMDFF Utilizer (vacuum and solution). In this work, three examples are shown to demonstrate the usage of MDFF/xMDFF Utilizer.
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Affiliation(s)
- Yifei Qi
- Department of Biological Sciences and Bioengineering Program, Lehigh University , 111 Research Drive, Bethlehem, Pennsylvania 18015, United States
| | - Jumin Lee
- Department of Biological Sciences and Bioengineering Program, Lehigh University , 111 Research Drive, Bethlehem, Pennsylvania 18015, United States
| | - Abhishek Singharoy
- Beckman Institute and Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Ryan McGreevy
- Beckman Institute and Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Klaus Schulten
- Beckman Institute and Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Wonpil Im
- Department of Biological Sciences and Bioengineering Program, Lehigh University , 111 Research Drive, Bethlehem, Pennsylvania 18015, United States
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370
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Thenin-Houssier S, Valente ST. HIV-1 Capsid Inhibitors as Antiretroviral Agents. Curr HIV Res 2016; 14:270-82. [PMID: 26957201 DOI: 10.2174/1570162x14999160224103555] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 08/12/2015] [Accepted: 09/01/2015] [Indexed: 01/09/2023]
Abstract
BACKGROUND The infectious human immunodeficiency virus (HIV) particle is characterized by a conical capsid that encloses the viral RNA genome. The capsid is essential for HIV-1 replication and plays crucial roles in both early and late stages of the viral life cycle. Early on, upon fusion of the viral and cellular membranes, the viral capsid is released into the host cell cytoplasm and dissociates in a process known as uncoating, tightly associated with the reverse transcription of the viral genome. During the late stages of viral replication, the Gag polyprotein, precursor of the capsid protein, assemble at the plasma membrane to form immature non-infectious viral particles. After a maturation step by the viral protease, the capsid assembles to form a fullerene-like conical shape characteristic of the mature infectious particle. Mutations affecting the uncoating process, or capsid assembly and maturation, have been shown to hamper viral infectivity. The key role of capsid in viral replication and the absence of approved drugs against this protein have promoted the development of antiretrovirals. Screening based on the inhibition of capsid assembly and virtual screening for molecules binding to the capsid have successfully identified a number of potential small molecule compounds. Unfortunately, none of these molecules is currently used in the clinic. CONCLUSION Here we review the discovery and the mechanism of action of the small molecules and peptides identified as capsid inhibitors, and discuss their therapeutic potential.
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Affiliation(s)
| | - Susana T Valente
- Department Immunology and Microbial Sciences, The Scripps Research Institute, 130 Scripps Way, 3C1, Jupiter, FL 33458, USA.
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371
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Path-sampling strategies for simulating rare events in biomolecular systems. Curr Opin Struct Biol 2016; 43:88-94. [PMID: 27984811 DOI: 10.1016/j.sbi.2016.11.019] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 11/18/2016] [Accepted: 11/21/2016] [Indexed: 12/20/2022]
Abstract
Despite more than three decades of effort with molecular dynamics simulations, long-timescale (ms and beyond) biologically relevant phenomena remain out of reach in most systems of interest. This is largely because important transitions, such as conformational changes and (un)binding events, tend to be rare for conventional simulations (<10μs). That is, conventional simulations will predominantly dwell in metastable states instead of making large transitions in complex biomolecular energy landscapes. In contrast, path sampling approaches focus computing effort specifically on transitions of interest. Such approaches have been in use for nearly 20 years in biomolecular systems and enabled the generation of pathways and calculation of rate constants for ms processes, including large protein conformational changes, protein folding, and protein (un)binding.
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372
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Ning J, Erdemci-Tandogan G, Yufenyuy EL, Wagner J, Himes BA, Zhao G, Aiken C, Zandi R, Zhang P. In vitro protease cleavage and computer simulations reveal the HIV-1 capsid maturation pathway. Nat Commun 2016; 7:13689. [PMID: 27958264 PMCID: PMC5159922 DOI: 10.1038/ncomms13689] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 10/24/2016] [Indexed: 12/23/2022] Open
Abstract
HIV-1 virions assemble as immature particles containing Gag polyproteins that are processed by the viral protease into individual components, resulting in the formation of mature infectious particles. There are two competing models for the process of forming the mature HIV-1 core: the disassembly and de novo reassembly model and the non-diffusional displacive model. To study the maturation pathway, we simulate HIV-1 maturation in vitro by digesting immature particles and assembled virus-like particles with recombinant HIV-1 protease and monitor the process with biochemical assays and cryoEM structural analysis in parallel. Processing of Gag in vitro is accurate and efficient and results in both soluble capsid protein and conical or tubular capsid assemblies, seemingly converted from immature Gag particles. Computer simulations further reveal probable assembly pathways of HIV-1 capsid formation. Combining the experimental data and computer simulations, our results suggest a sequential combination of both displacive and disassembly/reassembly processes for HIV-1 maturation. Two competing models—disassembly/reassembly and displacive—have been proposed for how immature spherical HIV virions transform into mature particles with conical cores. Here the authors provide evidence that both disassembly/reassembly and displacive processes occur sequentially during the maturation process.
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Affiliation(s)
- Jiying Ning
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 5th Avenue, Pittsburgh, Pennsylvania 15260, USA.,Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260, USA
| | - Gonca Erdemci-Tandogan
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
| | - Ernest L Yufenyuy
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| | - Jef Wagner
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
| | - Benjamin A Himes
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 5th Avenue, Pittsburgh, Pennsylvania 15260, USA
| | - Gongpu Zhao
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 5th Avenue, Pittsburgh, Pennsylvania 15260, USA.,Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260, USA
| | - Christopher Aiken
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260, USA.,Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| | - Roya Zandi
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
| | - Peijun Zhang
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 5th Avenue, Pittsburgh, Pennsylvania 15260, USA.,Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260, USA.,Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, UK.,Electron Bio-Imaging Centre, Diamond Light Sources, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
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373
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Bergman S, Lezon TR. Modeling global changes induced by local perturbations to the HIV-1 capsid. J Mol Graph Model 2016; 71:218-226. [PMID: 27951510 DOI: 10.1016/j.jmgm.2016.12.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 11/04/2016] [Accepted: 12/01/2016] [Indexed: 02/02/2023]
Abstract
The HIV-1 capsid is a conical protein shell made up of hexamers and pentamers of the capsid protein. The capsid houses the viral genome and replication machinery, and its opening, or uncoating, within the host cell marks a critical step in the HIV-1 lifecycle. Binding of host factors such as TRIM5α and cyclophilin A (CypA) can alter the capsid's stability, accelerating or delaying the onset of uncoating and disrupting infectivity. We employ coarse-grained computational modeling to investigate the effects of point mutations and host factor binding on HIV-1 capsid stability. We find that the largest fluctuations occur in the low-curvature regions of the capsid, and that its structural dynamics are affected by perturbations at the inter-hexamer interfaces and near the CypA binding loop, suggesting roles for these features in capsid stability. Our models show that linking capsid proteins across hexamers attenuates vibration in the low-curvature regions of the capsid, but that linking within hexamers does not. These results indicate a possible mechanism through which CypA binding alters capsid stability and highlight the utility of coarse-grained network modeling for understanding capsid mechanics.
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Affiliation(s)
- Shana Bergman
- Department of Computational and Systems Biology, University of Pittsburgh, Suite 3064 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA.
| | - Timothy R Lezon
- Department of Computational and Systems Biology, University of Pittsburgh, Suite 3064 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA; University of Pittsburgh Drug Discovery Institute, University of Pittsburgh, W965 Biomedical Science Tower, 200 Lothrop Street, Pittsburgh, PA 15261, USA.
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374
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Izadi S, Anandakrishnan R, Onufriev AV. Implicit Solvent Model for Million-Atom Atomistic Simulations: Insights into the Organization of 30-nm Chromatin Fiber. J Chem Theory Comput 2016; 12:5946-5959. [PMID: 27748599 PMCID: PMC5649046 DOI: 10.1021/acs.jctc.6b00712] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Molecular dynamics (MD) simulations based on the implicit solvent generalized Born (GB) models can provide significant computational advantages over the traditional explicit solvent simulations. However, the standard GB becomes prohibitively expensive for all-atom simulations of large structures; the model scales poorly, ∼n2, with the number of solute atoms. Here we combine our recently developed optimal point charge approximation (OPCA) with the hierarchical charge partitioning (HCP) approximation to present an ∼n log n multiscale, yet fully atomistic, GB model (GB-HCPO). The HCP approximation exploits the natural organization of biomolecules (atoms, groups, chains, and complexes) to partition the structure into multiple hierarchical levels of components. OPCA approximates the charge distribution for each of these components by a small number of point charges so that the low order multipole moments of these components are optimally reproduced. The approximate charges are then used for computing electrostatic interactions with distant components, while the full set of atomic charges are used for nearby components. We show that GB-HCPO can deliver up to 2 orders of magnitude speedup compared to the standard GB, with minimal impact on its accuracy. For large structures, GB-HCPO can approach the same nominal speed, as in nanoseconds per day, as the highly optimized explicit-solvent simulation based on particle mesh Ewald (PME). The increase in the nominal simulation speed, relative to the standard GB, coupled with substantially faster sampling of conformational space, relative to the explicit solvent, makes GB-HCPO a suitable candidate for MD simulation of large atomistic systems in implicit solvent. As a practical demonstration, we use GB-HCPO simulation to refine a ∼1.16 million atom structure of 30 nm chromatin fiber (40 nucleosomes). The refined structure suggests important details about spatial organization of the linker DNA and the histone tails in the fiber: (1) the linker DNA fills the core region, allowing the H3 histone tails to interact with the linker DNA, which is consistent with experiment; (2) H3 and H4 tails are found mostly in the core of the structure, closer to the helical axis of the fiber, while H2A and H2B are mostly solvent exposed. Potential functional consequences of these findings are discussed. GB-HCPO is implemented in the open source MD software NAB in Amber 2016.
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Affiliation(s)
- Saeed Izadi
- Department of Biomedical Engineering and Mechanics, ‡Biomedical Division, Edward Via College of Osteopathic Medicine, ¶Department of Computer Science and Physics, and §Center for Soft Matter and Biological Physics, Virginia Polytechnic Institute and State University , Blacksburg, Virginia 24061, United States
| | - Ramu Anandakrishnan
- Department of Biomedical Engineering and Mechanics, ‡Biomedical Division, Edward Via College of Osteopathic Medicine, ¶Department of Computer Science and Physics, and §Center for Soft Matter and Biological Physics, Virginia Polytechnic Institute and State University , Blacksburg, Virginia 24061, United States
| | - Alexey V Onufriev
- Department of Biomedical Engineering and Mechanics, ‡Biomedical Division, Edward Via College of Osteopathic Medicine, ¶Department of Computer Science and Physics, and §Center for Soft Matter and Biological Physics, Virginia Polytechnic Institute and State University , Blacksburg, Virginia 24061, United States
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375
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Ni R, Zhou J, Hossain N, Chau Y. Virus-inspired nucleic acid delivery system: Linking virus and viral mimicry. Adv Drug Deliv Rev 2016; 106:3-26. [PMID: 27473931 DOI: 10.1016/j.addr.2016.07.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 07/02/2016] [Accepted: 07/20/2016] [Indexed: 12/21/2022]
Abstract
Targeted delivery of nucleic acids into disease sites of human body has been attempted for decades, but both viral and non-viral vectors are yet to meet our expectations. Safety concerns and low delivery efficiency are the main limitations of viral and non-viral vectors, respectively. The structure of viruses is both ordered and dynamic, and is believed to be the key for effective transfection. Detailed understanding of the physical properties of viruses, their interaction with cellular components, and responses towards cellular environments leading to transfection would inspire the development of safe and effective non-viral vectors. To this goal, this review systematically summarizes distinctive features of viruses that are implied for efficient nucleic acid delivery but not yet fully explored in current non-viral vectors. The assembly and disassembly of viral structures, presentation of viral ligands, and the subcellular targeting of viruses are emphasized. Moreover, we describe the current development of cationic material-based viral mimicry (CVM) and structural viral mimicry (SVM) in these aspects. In light of the discrepancy, we identify future opportunities for rational design of viral mimics for the efficient delivery of DNA and RNA.
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Affiliation(s)
- Rong Ni
- Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Institute for Advanced Study, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Junli Zhou
- Department of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Naushad Hossain
- Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Ying Chau
- Department of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
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376
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Sadiq SK. Reaction-diffusion basis of retroviral infectivity. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2016; 374:rsta.2016.0148. [PMID: 27698042 PMCID: PMC5052732 DOI: 10.1098/rsta.2016.0148] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/22/2016] [Indexed: 05/27/2023]
Abstract
Retrovirus particle (virion) infectivity requires diffusion and clustering of multiple transmembrane envelope proteins (Env3) on the virion exterior, yet is triggered by protease-dependent degradation of a partially occluding, membrane-bound Gag polyprotein lattice on the virion interior. The physical mechanism underlying such coupling is unclear and only indirectly accessible via experiment. Modelling stands to provide insight but the required spatio-temporal range far exceeds current accessibility by all-atom or even coarse-grained molecular dynamics simulations. Nor do such approaches account for chemical reactions, while conversely, reaction kinetics approaches handle neither diffusion nor clustering. Here, a recently developed multiscale approach is considered that applies an ultra-coarse-graining scheme to treat entire proteins at near-single particle resolution, but which also couples chemical reactions with diffusion and interactions. A model is developed of Env3 molecules embedded in a truncated Gag lattice composed of membrane-bound matrix proteins linked to capsid subunits, with freely diffusing protease molecules. Simulations suggest that in the presence of Gag but in the absence of lateral lattice-forming interactions, Env3 diffuses comparably to Gag-absent Env3 Initial immobility of Env3 is conferred through lateral caging by matrix trimers vertically coupled to the underlying hexameric capsid layer. Gag cleavage by protease vertically decouples the matrix and capsid layers, induces both matrix and Env3 diffusion, and permits Env3 clustering. Spreading across the entire membrane surface reduces crowding, in turn, enhancing the effect and promoting infectivity.This article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'.
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Affiliation(s)
- S Kashif Sadiq
- Infection Biology Unit, Universitat Pompeu Fabra, Barcelona Biomedical Research Park (PRBB), C/Doctor Aiguader 88, 08003 Barcelona, Spain Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany
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377
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Yang M, Chan H, Zhao G, Bahng JH, Zhang P, Král P, Kotov NA. Self-assembly of nanoparticles into biomimetic capsid-like nanoshells. Nat Chem 2016; 9:287-294. [PMID: 28221348 DOI: 10.1038/nchem.2641] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 09/09/2016] [Indexed: 11/09/2022]
Abstract
Nanoscale compartments are one of the foundational elements of living systems. Capsids, carboxysomes, exosomes, vacuoles and other nanoshells easily self-assemble from biomolecules such as lipids or proteins, but not from inorganic nanomaterials because of difficulties with the replication of spherical tiling. Here we show that stabilizer-free polydispersed inorganic nanoparticles (NPs) can spontaneously organize into porous nanoshells. The association of water-soluble CdS NPs into self-limited spherical capsules is the result of scale-modified electrostatic, dispersion and other colloidal forces. They cannot be accurately described by the Derjaguin-Landau-Vervey-Overbeek theory, whereas molecular-dynamics simulations with combined atomistic and coarse-grained description of NPs reveal the emergence of nanoshells and some of their stabilization mechanisms. Morphology of the simulated assemblies formed under different conditions matched nearly perfectly the transmission electron microscopy tomography data. This study bridges the gap between biological and inorganic self-assembling nanosystems and conceptualizes a new pathway to spontaneous compartmentalization for a wide range of inorganic NPs including those existing on prebiotic Earth.
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Affiliation(s)
- Ming Yang
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA.,Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan 48109, USA.,Key Laboratory of Microsystems and Micronanostructures Manufacturing, Harbin Institute of Technology, Harbin 150080, China
| | - Henry Chan
- Department of Chemistry, University of Illinois in Chicago, Chicago, Illinois 60607, USA
| | - Gongpu Zhao
- Department of Structural Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Joong Hwan Bahng
- Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan 48109, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Peijun Zhang
- Department of Structural Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.,Department of Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Petr Král
- Department of Chemistry, University of Illinois in Chicago, Chicago, Illinois 60607, USA.,Department of Physics, University of Illinois in Chicago, Chicago, Illinois 60607, USA.,Department of Biopharmaceutical Sciences, University of Illinois in Chicago, Chicago, Illinois 60612, USA
| | - Nicholas A Kotov
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA.,Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan 48109, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA.,Department of Material Sciences and Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA.,Michigan Center for Integrative Research in Critical Care, Ann Arbor, Michigan 48109, USA
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378
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Spearman P. HIV-1 Gag as an Antiviral Target: Development of Assembly and Maturation Inhibitors. Curr Top Med Chem 2016; 16:1154-66. [PMID: 26329615 DOI: 10.2174/1568026615666150902102143] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 06/18/2015] [Accepted: 06/21/2015] [Indexed: 01/10/2023]
Abstract
HIV-1 Gag is the master orchestrator of particle assembly. The central role of Gag at multiple stages of the HIV lifecycle has led to efforts to develop drugs that directly target Gag and prevent the formation and release of infectious particles. Until recently, however, only the catalytic site protease inhibitors have been available to inhibit late stages of HIV replication. This review summarizes the current state of development of antivirals that target Gag or disrupt late events in the retrovirus lifecycle such as maturation of the viral capsid. Maturation inhibitors represent an exciting new series of antiviral compounds, including those that specifically target CA-SP1 cleavage and the allosteric integrase inhibitors that inhibit maturation by a completely different mechanism. Numerous small molecules and peptides targeting CA have been studied in attempts to disrupt steps in assembly. Efforts to target CA have recently gained considerable momentum from the development of small molecules that bind CA and alter capsid stability at the post-entry stage of the lifecycle. Efforts to develop antivirals that inhibit incorporation of genomic RNA or to inhibit late budding events remain in preliminary stages of development. Overall, the development of novel antivirals targeting Gag and the late stages in HIV replication appears much closer to success than ever, with the new maturation inhibitors leading the way.
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Affiliation(s)
- Paul Spearman
- Department of Pediatrics; Pediatric Infectious Diseases, Emory University, 2015 Uppergate Drive, Atlanta, GA 30322.
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379
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Ball NJ, Nicastro G, Dutta M, Pollard DJ, Goldstone DC, Sanz-Ramos M, Ramos A, Müllers E, Stirnnagel K, Stanke N, Lindemann D, Stoye JP, Taylor WR, Rosenthal PB, Taylor IA. Structure of a Spumaretrovirus Gag Central Domain Reveals an Ancient Retroviral Capsid. PLoS Pathog 2016; 12:e1005981. [PMID: 27829070 PMCID: PMC5102385 DOI: 10.1371/journal.ppat.1005981] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 10/06/2016] [Indexed: 12/26/2022] Open
Abstract
The Spumaretrovirinae, or foamy viruses (FVs) are complex retroviruses that infect many species of monkey and ape. Despite little sequence homology, FV and orthoretroviral Gag proteins perform equivalent functions, including genome packaging, virion assembly, trafficking and membrane targeting. However, there is a paucity of structural information for FVs and it is unclear how disparate FV and orthoretroviral Gag molecules share the same function. To probe the functional overlap of FV and orthoretroviral Gag we have determined the structure of a central region of Gag from the Prototype FV (PFV). The structure comprises two all α-helical domains NtDCEN and CtDCEN that although they have no sequence similarity, we show they share the same core fold as the N- (NtDCA) and C-terminal domains (CtDCA) of archetypal orthoretroviral capsid protein (CA). Moreover, structural comparisons with orthoretroviral CA align PFV NtDCEN and CtDCEN with NtDCA and CtDCA respectively. Further in vitro and functional virological assays reveal that residues making inter-domain NtDCEN-CtDCEN interactions are required for PFV capsid assembly and that intact capsid is required for PFV reverse transcription. These data provide the first information that relates the Gag proteins of Spuma and Orthoretrovirinae and suggests a common ancestor for both lineages containing an ancient CA fold.
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Affiliation(s)
- Neil J. Ball
- Macromolecular Structure Laboratory, The Francis Crick Institute, Mill Hill Laboratory, London, United Kingdom
| | - Giuseppe Nicastro
- Macromolecular Structure Laboratory, The Francis Crick Institute, Mill Hill Laboratory, London, United Kingdom
| | - Moumita Dutta
- Structural Biology of Cells and Viruses, The Francis Crick Institute, Mill Hill Laboratory, London, United Kingdom
| | - Dominic J. Pollard
- Macromolecular Structure Laboratory, The Francis Crick Institute, Mill Hill Laboratory, London, United Kingdom
| | - David C. Goldstone
- Macromolecular Structure Laboratory, The Francis Crick Institute, Mill Hill Laboratory, London, United Kingdom
| | - Marta Sanz-Ramos
- Retrovirus-Host Interactions Laboratory, The Francis Crick Institute, Mill Hill Laboratory, London, United Kingdom
| | - Andres Ramos
- Macromolecular Structure Laboratory, The Francis Crick Institute, Mill Hill Laboratory, London, United Kingdom
| | - Erik Müllers
- Institute of Virology, Technische Universität Dresden, Dresden, DE
| | | | - Nicole Stanke
- Institute of Virology, Technische Universität Dresden, Dresden, DE
| | - Dirk Lindemann
- Institute of Virology, Technische Universität Dresden, Dresden, DE
| | - Jonathan P. Stoye
- Retrovirus-Host Interactions Laboratory, The Francis Crick Institute, Mill Hill Laboratory, London, United Kingdom
- Faculty of Medicine, Imperial College London, London, United Kingdom
| | - William R. Taylor
- Computational Cell and Molecular Biology Laboratory, The Francis Crick Institute, Mill Hill Laboratory, London, United Kingdom
| | - Peter B. Rosenthal
- Structural Biology of Cells and Viruses, The Francis Crick Institute, Mill Hill Laboratory, London, United Kingdom
| | - Ian A. Taylor
- Macromolecular Structure Laboratory, The Francis Crick Institute, Mill Hill Laboratory, London, United Kingdom
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380
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Roshal DS, Konevtsova OV, Myasnikova AE, Rochal SB. Assembly of the most topologically regular two-dimensional micro and nanocrystals with spherical, conical, and tubular shapes. Phys Rev E 2016; 94:052605. [PMID: 27967001 DOI: 10.1103/physreve.94.052605] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Indexed: 06/06/2023]
Abstract
We consider how to control the extension of curvature-induced defects in the hexagonal order covering different curved surfaces. In these frames we propose a physical mechanism for improving structures of two-dimensional spherical colloidal crystals (SCCs). For any SCC comprising of about 300 or less particles the mechanism transforms all extended topological defects (ETDs) in the hexagonal order into the point disclinations. Perfecting the structure is carried out by successive cycles of the particle implantation and subsequent relaxation of the crystal. The mechanism is potentially suitable for obtaining colloidosomes with better selective permeability. Our approach enables modeling the most topologically regular tubular and conical two-dimensional nanocrystals including various possible polymorphic forms of the HIV viral capsid. Different HIV-like shells with an arbitrary number of structural units (SUs) and desired geometrical parameters are easily formed. Faceting of the obtained structures is performed by minimizing the suggested elastic energy.
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Affiliation(s)
- D S Roshal
- Faculty of Physics, Southern Federal University, 5 Zorge strasse, 344090 Rostov-on-Don, Russia
| | - O V Konevtsova
- Faculty of Physics, Southern Federal University, 5 Zorge strasse, 344090 Rostov-on-Don, Russia
| | - A E Myasnikova
- Faculty of Physics, Southern Federal University, 5 Zorge strasse, 344090 Rostov-on-Don, Russia
| | - S B Rochal
- Faculty of Physics, Southern Federal University, 5 Zorge strasse, 344090 Rostov-on-Don, Russia
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381
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Zhang H, Hou G, Lu M, Ahn J, Byeon IJL, Langmead CJ, Perilla JR, Hung I, Gor’kov PL, Gan Z, Brey WW, Case DA, Schulten K, Gronenborn AM, Polenova T. HIV-1 Capsid Function Is Regulated by Dynamics: Quantitative Atomic-Resolution Insights by Integrating Magic-Angle-Spinning NMR, QM/MM, and MD. J Am Chem Soc 2016; 138:14066-14075. [PMID: 27701859 PMCID: PMC5380593 DOI: 10.1021/jacs.6b08744] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
HIV-1 CA capsid protein possesses intrinsic conformational flexibility, which is essential for its assembly into conical capsids and interactions with host factors. CA is dynamic in the assembled capsid, and residues in functionally important regions of the protein undergo motions spanning many decades of time scales. Chemical shift anisotropy (CSA) tensors, recorded in magic-angle-spinning NMR experiments, provide direct residue-specific probes of motions on nano- to microsecond time scales. We combined NMR, MD, and density-functional-theory calculations, to gain quantitative understanding of internal backbone dynamics in CA assemblies, and we found that the dynamically averaged 15N CSA tensors calculated by this joined protocol are in remarkable agreement with experiment. Thus, quantitative atomic-level understanding of the relationships between CSA tensors, local backbone structure, and motions in CA assemblies is achieved, demonstrating the power of integrating NMR experimental data and theory for characterizing atomic-resolution dynamics in biological systems.
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Affiliation(s)
- Huilan Zhang
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
| | - Guangjin Hou
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
| | - Manman Lu
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
| | - Jinwoo Ahn
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
| | - In-Ja L. Byeon
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
| | - Christopher J. Langmead
- Computer Science Department, Carnegie Mellon University, Gates Hillman Center, 5000 Forbes Avenue, Pittsburgh, PA, United States
| | - Juan R. Perilla
- Department of Physics and Beckman Institute for Advanced Science and Technology University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Ivan Hung
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, United States
| | - Peter L. Gor’kov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, United States
| | - Zhehong Gan
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, United States
| | - William W. Brey
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, United States
| | - David A. Case
- Department of Chemistry and Chemical Biology, Rutgers University, 174 Frelinghuysen Road, Piscataway, NJ 08854-8087, United States
| | - Klaus Schulten
- Department of Physics and Beckman Institute for Advanced Science and Technology University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Angela M. Gronenborn
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
| | - Tatyana Polenova
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
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382
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Jung J, Sugita Y. Multiple program/multiple data molecular dynamics method with multiple time step integrator for large biological systems. J Comput Chem 2016; 38:1410-1418. [PMID: 27709646 DOI: 10.1002/jcc.24511] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 09/19/2016] [Accepted: 09/20/2016] [Indexed: 12/17/2022]
Abstract
Parallelization of molecular dynamics (MD) simulation is essential for investigating conformational dynamics of large biological systems, such as ribosomes, viruses, and multiple proteins in cellular environments. To improve efficiency in the parallel computation, we have to reduce the amount of data transfer between processors by introducing domain decomposition schemes. Also, it is important to optimize the computational balance between real-space non-bonded interactions and reciprocal-space interactions for long-range electrostatic interactions. Here, we introduce a novel parallelization scheme for large-scale MD simulations on massively parallel supercomputers consisting of only CPUs. We make use of a multiple program/multiple data (MPMD) approach for separating the real-space and reciprocal-space computations on different processors. We also utilize the r-RESPA multiple time step integrator on the framework of the MPMD approach in an efficient way: when the reciprocal-space computations are skipped in r-RESPA, processors assigned for them are utilized for half of the real-space computations. The new scheme allows us to use twice as many as processors that are available in the conventional single program approach. The best performances of all-atom MD simulations for 1 million (STMV), 8.5 million (8_STMV), and 28.8 million (27_STMV) atom systems on K computer are 65, 36, and 24 ns/day, respectively. The MPMD scheme can accelerate 23.4, 10.2, and 9.2 ns/day from the maximum performance of single-program approach for STMV, 8_STMV, and 27_STMV systems, respectively, which correspond to 57%, 39%, and 60% speed up. This suggests significant speedups by increasing the number of processors without losing parallel computational efficiency. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Jaewoon Jung
- Computational Biophysics Research Team, RIKEN Advanced Institute for Computational Science, 7-1-26 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo Kobe, 640-0047, Japan.,RIKEN Theoretical Molecular Science Laboratory, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan
| | - Yuji Sugita
- Computational Biophysics Research Team, RIKEN Advanced Institute for Computational Science, 7-1-26 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo Kobe, 640-0047, Japan.,RIKEN Theoretical Molecular Science Laboratory, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan.,Laboratory for Biomolecular Function Simulation, RIKEN Quantitative Biology Center (QBiC), IIB 7F, 6-7-1 Minatojimaminami-machi, Chuo-ku, Kobe, Hyogo, 650-0047, Japan.,RIKEN iTHES, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan
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383
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Chavent M, Duncan AL, Sansom MS. Molecular dynamics simulations of membrane proteins and their interactions: from nanoscale to mesoscale. Curr Opin Struct Biol 2016; 40:8-16. [PMID: 27341016 PMCID: PMC5404110 DOI: 10.1016/j.sbi.2016.06.007] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 06/06/2016] [Accepted: 06/07/2016] [Indexed: 11/21/2022]
Abstract
Molecular dynamics simulations provide a computational tool to probe membrane proteins and systems at length scales ranging from nanometers to close to a micrometer, and on microsecond timescales. All atom and coarse-grained simulations may be used to explore in detail the interactions of membrane proteins and specific lipids, yielding predictions of lipid binding sites in good agreement with available structural data. Building on the success of protein-lipid interaction simulations, larger scale simulations reveal crowding and clustering of proteins, resulting in slow and anomalous diffusional dynamics, within realistic models of cell membranes. Current methods allow near atomic resolution simulations of small membrane organelles, and of enveloped viruses to be performed, revealing key aspects of their structure and functionally important dynamics.
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Affiliation(s)
- Matthieu Chavent
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Anna L Duncan
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Mark Sp Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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384
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Da Silva Santos C, Tartour K, Cimarelli A. A Novel Entry/Uncoating Assay Reveals the Presence of at Least Two Species of Viral Capsids During Synchronized HIV-1 Infection. PLoS Pathog 2016; 12:e1005897. [PMID: 27690375 PMCID: PMC5045187 DOI: 10.1371/journal.ppat.1005897] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 08/26/2016] [Indexed: 12/17/2022] Open
Abstract
To better characterize the behavior of HIV-1 capsids we developed EURT, for Entry/Uncoating assay based on core-packaged RNA availability and Translation. EURT is an alternative to Blam-Vpr, but as reporter RNA translation relies on core opening, it can be used to study viral capsids behavior. Our study reveals the existence of two major capsid species, a dead end one in which the viral genome is readily exposed to the cytoplasm and a functional one in which such exposure requires artificial core destabilization. Although reverse transcription drives a faster loss of susceptibility of viral cores to high doses of PF74, it does not lead to higher exposure of the viral genome, implying that viral cores protect the genome irrespectively of reverse transcription. Lastly, IFNα drifts cores from functional to non-functional species, revealing a novel core-destabilizing activity. This assay sheds new light on the behavior of viral cores inside target cells. Following viral-to-cellular membrane fusion, the HIV-1 genome is propelled inside the cell as part of an higher order nucleoproteic structure often referred to as viral core, or capsid. Here, we have developed a novel entry/uncoating assay based on the degree of exposure of a virion-packaged mRNA reporter to the translation machinery (EURT). Using this assay, we highlight here that at least two measurable kinds of viral capsids coexist during HIV-1 infection: one defined as open, in which the viral genome is readily accessible to translation and another that we define as closed, in which access to the genome is prevented until the artificial destabilization of capsids. Our data points to the former as dead-end products of infection and indicate the latter as the commonly referred infectious viral cores. Interestingly, we show here that despite the fact that reverse transcription reshapes viral cores, these structures maintain an exquisite ability to shield the viral genome from the cytoplasmic environment. Finally, IFNα that negatively impacts HIV-1 replication increases the proportion of open viral cores to the detriment of closed ones, suggesting a core-destabilizing activity driven by interferon-regulated proteins. Overall, this assay sheds new light on the behavior of viral cores inside target cells.
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Affiliation(s)
- Claire Da Silva Santos
- CIRI, Centre International de Recherche en Infectiologie, 46 Allée d’Italie, Lyon F69364, France
- INSERM, U1111, 46 Allée d’Italie, Lyon, F69364, France
- Université Claude Bernard Lyon I, 46 Allée d’Italie, Lyon, F69364, France
- CNRS, UMR5308, 46 Allée d’Italie, Lyon, F69364, France
- Ecole Normale Supérieure de Lyon, 46 Allée d’Italie, Lyon, F69364, France
- Université de Lyon, Lyon, France
| | - Kevin Tartour
- CIRI, Centre International de Recherche en Infectiologie, 46 Allée d’Italie, Lyon F69364, France
- INSERM, U1111, 46 Allée d’Italie, Lyon, F69364, France
- Université Claude Bernard Lyon I, 46 Allée d’Italie, Lyon, F69364, France
- CNRS, UMR5308, 46 Allée d’Italie, Lyon, F69364, France
- Ecole Normale Supérieure de Lyon, 46 Allée d’Italie, Lyon, F69364, France
- Université de Lyon, Lyon, France
| | - Andrea Cimarelli
- CIRI, Centre International de Recherche en Infectiologie, 46 Allée d’Italie, Lyon F69364, France
- INSERM, U1111, 46 Allée d’Italie, Lyon, F69364, France
- Université Claude Bernard Lyon I, 46 Allée d’Italie, Lyon, F69364, France
- CNRS, UMR5308, 46 Allée d’Italie, Lyon, F69364, France
- Ecole Normale Supérieure de Lyon, 46 Allée d’Italie, Lyon, F69364, France
- Université de Lyon, Lyon, France
- * E-mail:
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385
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Jung J, Naurse A, Kobayashi C, Sugita Y. Graphics Processing Unit Acceleration and Parallelization of GENESIS for Large-Scale Molecular Dynamics Simulations. J Chem Theory Comput 2016; 12:4947-4958. [DOI: 10.1021/acs.jctc.6b00241] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jaewoon Jung
- RIKEN Theoretical Molecular Science Laboratory, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- RIKEN Advanced Institute for Computational Science, 7-1-26 minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 640-0047, Japan
| | - Akira Naurse
- NVIDIA, 2-11-7, Akasaka,
Minato-ku, Tokyo 107-0052, Japan
| | - Chigusa Kobayashi
- RIKEN Advanced Institute for Computational Science, 7-1-26 minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 640-0047, Japan
| | - Yuji Sugita
- RIKEN Theoretical Molecular Science Laboratory, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- RIKEN Advanced Institute for Computational Science, 7-1-26 minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 640-0047, Japan
- RIKEN iTHES, 2-1 Hirosawa,
Wako, Saitama 351-0198, Japan
- Laboratory
for Biomolecular Function Simulation, RIKEN Quantitative Biology Center (QBiC), 6-7-1 minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
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386
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Chen Y, Roux B. Constant-pH Hybrid Nonequilibrium Molecular Dynamics-Monte Carlo Simulation Method. J Chem Theory Comput 2016; 11:3919-31. [PMID: 26300709 PMCID: PMC4535364 DOI: 10.1021/acs.jctc.5b00261] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A computational method is developed to carry out explicit solvent simulations of complex molecular systems under conditions of constant pH. In constant-pH simulations, preidentified ionizable sites are allowed to spontaneously protonate and deprotonate as a function of time in response to the environment and the imposed pH. The method, based on a hybrid scheme originally proposed by H. A. Stern (J. Chem. Phys. 2007, 126, 164112), consists of carrying out short nonequilibrium molecular dynamics (neMD) switching trajectories to generate physically plausible configurations with changed protonation states that are subsequently accepted or rejected according to a Metropolis Monte Carlo (MC) criterion. To ensure microscopic detailed balance arising from such nonequilibrium switches, the atomic momenta are altered according to the symmetric two-ends momentum reversal prescription. To achieve higher efficiency, the original neMD-MC scheme is separated into two steps, reducing the need for generating a large number of unproductive and costly nonequilibrium trajectories. In the first step, the protonation state of a site is randomly attributed via a Metropolis MC process on the basis of an intrinsic pKa; an attempted nonequilibrium switch is generated only if this change in protonation state is accepted. This hybrid two-step inherent pKa neMD-MC simulation method is tested with single amino acids in solution (Asp, Glu, and His) and then applied to turkey ovomucoid third domain and hen egg-white lysozyme. Because of the simple linear increase in the computational cost relative to the number of titratable sites, the present method is naturally able to treat extremely large systems.
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Affiliation(s)
- Yunjie Chen
- Department of Biochemistry and Molecular Biology, Department of Chemistry, University of Chicago , Chicago, Illinois 60637, United States
| | - Benoît Roux
- Department of Biochemistry and Molecular Biology, Department of Chemistry, University of Chicago , Chicago, Illinois 60637, United States
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387
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Bayro MJ, Ganser-Pornillos BK, Zadrozny KK, Yeager M, Tycko R. Helical Conformation in the CA-SP1 Junction of the Immature HIV-1 Lattice Determined from Solid-State NMR of Virus-like Particles. J Am Chem Soc 2016; 138:12029-32. [PMID: 27593947 DOI: 10.1021/jacs.6b07259] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Maturation of HIV-1 requires disassembly of the Gag polyprotein lattice, which lines the viral membrane in the immature state, and subsequent assembly of the mature capsid protein lattice, which encloses viral RNA in the mature state. Metastability of the immature lattice has been proposed to depend on the existence of a structurally ordered, α-helical segment spanning the junction between capsid (CA) and spacer peptide 1 (SP1) subunits of Gag, a segment that is dynamically disordered in the mature capsid lattice. We report solid state nuclear magnetic resonance (ssNMR) measurements on the immature lattice in noncrystalline, spherical virus-like particles (VLPs) derived from Gag. The ssNMR data provide definitive evidence for this critical α-helical segment in the VLPs. Differences in ssNMR chemical shifts and signal intensities between immature and mature lattice assemblies also support a major rearrangement of intermolecular interactions in the maturation process, consistent with recent models from electron cryomicroscopy and X-ray crystallography.
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Affiliation(s)
- Marvin J Bayro
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892-0520, United States
| | - Barbie K Ganser-Pornillos
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine , Seridan G. Snyder Translational Research Building, 480 Ray C. Hunt Drive, Charlottesville, Virginia 22908, United States
| | - Kaneil K Zadrozny
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine , Seridan G. Snyder Translational Research Building, 480 Ray C. Hunt Drive, Charlottesville, Virginia 22908, United States
| | - Mark Yeager
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine , Seridan G. Snyder Translational Research Building, 480 Ray C. Hunt Drive, Charlottesville, Virginia 22908, United States.,Department of Medicine, Division of Cardiovascular Medicine, University of Virginia Health System , Charlottesville, Virginia 22908, United States.,Center for Membrane and Cell Physiology, University of Virginia School of Medicine , Charlottesville, Virginia 22908, United States
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892-0520, United States
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388
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McCullagh P, Lake PT, McCullagh M. Deriving Coarse-Grained Charges from All-Atom Systems: An Analytic Solution. J Chem Theory Comput 2016; 12:4390-9. [DOI: 10.1021/acs.jctc.6b00507] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Peter McCullagh
- Department
of Statistics, University of Chicago, Chicago, Illinois 60637, United States
| | - Peter T. Lake
- Department
of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Martin McCullagh
- Department
of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
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389
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Bekker GJ, Nakamura H, Kinjo AR. Molmil: a molecular viewer for the PDB and beyond. J Cheminform 2016; 8:42. [PMID: 27570544 PMCID: PMC5002144 DOI: 10.1186/s13321-016-0155-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 08/19/2016] [Indexed: 11/17/2022] Open
Abstract
We have developed a new platform-independent web-based molecular viewer using JavaScript and WebGL. The molecular viewer, Molmil, has been integrated into several services offered by Protein Data Bank Japan and can be easily extended with new functionality by third party developers. Furthermore, the viewer can be used to load files in various formats from the user’s local hard drive without uploading the data to a server. Molmil is available for all platforms supporting WebGL (e.g. Windows, Linux, iOS, Android) from http://gjbekker.github.io/molmil/. The source code is available at http://github.com/gjbekker/molmil under the LGPLv3 licence.
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Affiliation(s)
- Gert-Jan Bekker
- Laboratory of Protein Informatics, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871 Japan ; Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871 Japan
| | - Haruki Nakamura
- Laboratory of Protein Informatics, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871 Japan
| | - Akira R Kinjo
- Laboratory of Protein Informatics, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871 Japan
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390
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Sapin E, Carr DB, De Jong KA, Shehu A. Computing energy landscape maps and structural excursions of proteins. BMC Genomics 2016; 17 Suppl 4:546. [PMID: 27535545 PMCID: PMC5001232 DOI: 10.1186/s12864-016-2798-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Structural excursions of a protein at equilibrium are key to biomolecular recognition and function modulation. Protein modeling research is driven by the need to aid wet laboratories in characterizing equilibrium protein dynamics. In principle, structural excursions of a protein can be directly observed via simulation of its dynamics, but the disparate temporal scales involved in such excursions make this approach computationally impractical. On the other hand, an informative representation of the structure space available to a protein at equilibrium can be obtained efficiently via stochastic optimization, but this approach does not directly yield information on equilibrium dynamics. METHODS We present here a novel methodology that first builds a multi-dimensional map of the energy landscape that underlies the structure space of a given protein and then queries the computed map for energetically-feasible excursions between structures of interest. An evolutionary algorithm builds such maps with a practical computational budget. Graphical techniques analyze a computed multi-dimensional map and expose interesting features of an energy landscape, such as basins and barriers. A path searching algorithm then queries a nearest-neighbor graph representation of a computed map for energetically-feasible basin-to-basin excursions. RESULTS Evaluation is conducted on intrinsically-dynamic proteins of importance in human biology and disease. Visual statistical analysis of the maps of energy landscapes computed by the proposed methodology reveals features already captured in the wet laboratory, as well as new features indicative of interesting, unknown thermodynamically-stable and semi-stable regions of the equilibrium structure space. Comparison of maps and structural excursions computed by the proposed methodology on sequence variants of a protein sheds light on the role of equilibrium structure and dynamics in the sequence-function relationship. CONCLUSIONS Applications show that the proposed methodology is effective at locating basins in complex energy landscapes and computing basin-basin excursions of a protein with a practical computational budget. While the actual temporal scales spanned by a structural excursion cannot be directly obtained due to the foregoing of simulation of dynamics, hypotheses can be formulated regarding the impact of sequence mutations on protein function. These hypotheses are valuable in instigating further research in wet laboratories.
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Affiliation(s)
- Emmanuel Sapin
- Department of Computer Science, George Mason University, 4400 University Drive, Fairfax, 22030, VA, USA
| | - Daniel B Carr
- Department of Statistics, George Mason University, 4400 University Drive, Fairfax, 22030, VA, USA
| | - Kenneth A De Jong
- Department of Computer Science, George Mason University, 4400 University Drive, Fairfax, 22030, VA, USA.,Krasnow Institute for Advanced Study, George Mason University, 4400 University Drive, Fairfax, 22030, VA, USA
| | - Amarda Shehu
- Department of Computer Science, George Mason University, 4400 University Drive, Fairfax, 22030, VA, USA. amarda.@gmu.edu.,Department of Bioengineering, George Mason University, 4400 University Drive, Fairfax, 22030, VA, USA. amarda.@gmu.edu.,School of Systems Biology, George Mason University, 10900 University Boulevard, Manassas, 20110, VA, USA. amarda.@gmu.edu
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391
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Jacques DA, McEwan WA, Hilditch L, Price AJ, Towers GJ, James LC. HIV-1 uses dynamic capsid pores to import nucleotides and fuel encapsidated DNA synthesis. Nature 2016; 536:349-53. [PMID: 27509857 PMCID: PMC4998957 DOI: 10.1038/nature19098] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 07/12/2016] [Indexed: 12/21/2022]
Abstract
During the early stages of infection, the HIV-1 capsid protects viral components from cytosolic sensors and nucleases such as cGAS and TREX, respectively, while allowing access to nucleotides for efficient reverse transcription. Here we show that each capsid hexamer has a size-selective pore bound by a ring of six arginine residues and a 'molecular iris' formed by the amino-terminal β-hairpin. The arginine ring creates a strongly positively charged channel that recruits the four nucleotides with on-rates that approach diffusion limits. Progressive removal of pore arginines results in a dose-dependent and concomitant decrease in nucleotide affinity, reverse transcription and infectivity. This positively charged channel is universally conserved in lentiviral capsids despite the fact that it is strongly destabilizing without nucleotides to counteract charge repulsion. We also describe a channel inhibitor, hexacarboxybenzene, which competes for nucleotide binding and efficiently blocks encapsidated reverse transcription, demonstrating the tractability of the pore as a novel drug target.
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392
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Jayaraman B, Smith AM, Fernandes JD, Frankel AD. Oligomeric viral proteins: small in size, large in presence. Crit Rev Biochem Mol Biol 2016; 51:379-394. [PMID: 27685368 DOI: 10.1080/10409238.2016.1215406] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Viruses are obligate parasites that rely heavily on host cellular processes for replication. The small number of proteins typically encoded by a virus is faced with selection pressures that lead to the evolution of distinctive structural properties, allowing each protein to maintain its function under constraints such as small genome size, high mutation rate, and rapidly changing fitness conditions. One common strategy for this evolution is to utilize small building blocks to generate protein oligomers that assemble in multiple ways, thereby diversifying protein function and regulation. In this review, we discuss specific cases that illustrate how oligomerization is used to generate a single defined functional state, to modulate activity via different oligomeric states, or to generate multiple functional forms via different oligomeric states.
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Affiliation(s)
- Bhargavi Jayaraman
- a Department of Biochemistry and Biophysics , University of California , San Francisco , CA , USA
| | - Amber M Smith
- a Department of Biochemistry and Biophysics , University of California , San Francisco , CA , USA
| | - Jason D Fernandes
- b UC Santa Cruz Genomics Institute , Santa Cruz , CA , USA.,c Howard Hughes Medical Institute, University of California , Santa Cruz , CA , USA
| | - Alan D Frankel
- a Department of Biochemistry and Biophysics , University of California , San Francisco , CA , USA
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393
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DiMaio F, Chiu W. Tools for Model Building and Optimization into Near-Atomic Resolution Electron Cryo-Microscopy Density Maps. Methods Enzymol 2016; 579:255-76. [PMID: 27572730 PMCID: PMC5103630 DOI: 10.1016/bs.mie.2016.06.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Electron cryo-microscopy (cryoEM) has advanced dramatically to become a viable tool for high-resolution structural biology research. The ultimate outcome of a cryoEM study is an atomic model of a macromolecule or its complex with interacting partners. This chapter describes a variety of algorithms and software to build a de novo model based on the cryoEM 3D density map, to optimize the model with the best stereochemistry restraints and finally to validate the model with proper protocols. The full process of atomic structure determination from a cryoEM map is described. The tools outlined in this chapter should prove extremely valuable in revealing atomic interactions guided by cryoEM data.
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Affiliation(s)
- F DiMaio
- University of Washington, Seattle, WA, United States; Institute for Protein Design, University of Washington, Seattle, WA, United States.
| | - W Chiu
- National Center for Macromolecular Imaging, Baylor College of Medicine, Houston, TX, United States.
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394
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Marzinek J, Holdbrook D, Huber R, Verma C, Bond P. Pushing the Envelope: Dengue Viral Membrane Coaxed into Shape by Molecular Simulations. Structure 2016; 24:1410-1420. [DOI: 10.1016/j.str.2016.05.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 05/09/2016] [Accepted: 05/11/2016] [Indexed: 11/26/2022]
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395
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Wagner JM, Zadrozny KK, Chrustowicz J, Purdy MD, Yeager M, Ganser-Pornillos BK, Pornillos O. Crystal structure of an HIV assembly and maturation switch. eLife 2016; 5. [PMID: 27416583 PMCID: PMC4946879 DOI: 10.7554/elife.17063] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 06/13/2016] [Indexed: 12/25/2022] Open
Abstract
Virus assembly and maturation proceed through the programmed operation of molecular switches, which trigger both local and global structural rearrangements to produce infectious particles. HIV-1 contains an assembly and maturation switch that spans the C-terminal domain (CTD) of the capsid (CA) region and the first spacer peptide (SP1) of the precursor structural protein, Gag. The crystal structure of the CTD-SP1 Gag fragment is a goblet-shaped hexamer in which the cup comprises the CTD and an ensuing type II β-turn, and the stem comprises a 6-helix bundle. The β-turn is critical for immature virus assembly and the 6-helix bundle regulates proteolysis during maturation. This bipartite character explains why the SP1 spacer is a critical element of HIV-1 Gag but is not a universal property of retroviruses. Our results also indicate that HIV-1 maturation inhibitors suppress unfolding of the CA-SP1 junction and thereby delay access of the viral protease to its substrate. DOI:http://dx.doi.org/10.7554/eLife.17063.001 Viruses like HIV must undergo a process called maturation in order to successfully infect cells. Maturation involves a dramatic rearrangement in the architecture of the virus. That is to say, the virus’s internal protein coat – called the capsid – must change from an immature sphere into a mature cone-shaped coat. Notably, this maturation process is what is disrupted by the protease inhibitors that are a major component of anti-HIV drug cocktails. Structural changes in small portions of the capsid protein, termed molecular switches, commonly trigger the viral capsids to reorganize. The HIV capsid has two of these switches, and Wagner, Zadrozny et al. set out to understand how one of them – called the CA-SP1 switch – works. Solving the three-dimensional structure of the immature form of the CA-SP1 switch revealed that it forms a well-structured bundle of six helices. This helical bundle captures another section of the capsid protein that would otherwise be cut by a viral protease. The CA-SP1 switch therefore controls how quickly the protein is cut and the start of the maturation process. Wagner, Zadrozny et al. then discovered that other small molecule inhibitors of HIV, called maturation inhibitors, work by binding to and disrupting the transformation of the CA-SP1 switch. Finally, further experiments showed that the formation of the CA-SP1 helical bundle controls when the immature capsid shell forms and coordinates the process with the capsid gaining the genetic material of the virus. The new structure means that researchers now know what the HIV capsid looks like at the start and end of maturation. The next challenge will be to figure out exactly how the capsid changes from one form to the next as HIV matures. DOI:http://dx.doi.org/10.7554/eLife.17063.002
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Affiliation(s)
- Jonathan M Wagner
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, United States
| | - Kaneil K Zadrozny
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, United States
| | - Jakub Chrustowicz
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, United States
| | - Michael D Purdy
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, United States
| | - Mark Yeager
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, United States.,Department of Medicine, Division of Cardiovascular Medicine, University of Virginia Health System, Charlottesville, United States
| | - Barbie K Ganser-Pornillos
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, United States
| | - Owen Pornillos
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, United States
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396
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Bayro MJ, Tycko R. Structure of the Dimerization Interface in the Mature HIV-1 Capsid Protein Lattice from Solid State NMR of Tubular Assemblies. J Am Chem Soc 2016; 138:8538-46. [PMID: 27298207 PMCID: PMC5550895 DOI: 10.1021/jacs.6b03983] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The HIV-1 capsid protein (CA) forms the capsid shell that encloses RNA within a mature HIV-1 virion. Previous studies by electron microscopy have shown that the capsid shell is primarily a triangular lattice of CA hexamers, with variable curvature that destroys the ideal symmetry of a planar lattice. The mature CA lattice depends on CA dimerization, which occurs through interactions between helix 9 segments of the C-terminal domain (CTD) of CA. Several high-resolution structures of the CTD-CTD dimerization interface have been reported, based on X-ray crystallography and multidimensional solution nuclear magnetic resonance (NMR), with significant differences in amino acid side chain conformations and helix 9-helix 9 orientations. In a structural model for tubular CA assemblies based on cryogenic electron microscopy (cryoEM) [Zhao et al. Nature, 2013, 497, 643-646], the dimerization interface is substantially disordered. The dimerization interface structure in noncrystalline CA assemblies and the extent to which this interface is structurally ordered within a curved lattice have therefore been unclear. Here we describe solid state NMR measurements on the dimerization interface in tubular CA assemblies, which contain the curved triangular lattice of a mature virion, including quantitative measurements of intermolecular and intramolecular distances using dipolar recoupling techniques, solid state NMR chemical shifts, and long-range side chain-side chain contacts. When combined with restraints on the distance and orientation between helix 9 segments from the cryoEM study, the solid state NMR data lead to a unique high-resolution structure for the dimerization interface in the noncrystalline lattice of CA tubes. These results demonstrate that CA lattice curvature is not dependent on disorder or variability in the dimerization interface. This work also demonstrates the feasibility of local structure determination within large noncrystalline assemblies formed by high-molecular-weight proteins, using modern solid state NMR methods.
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Affiliation(s)
- Marvin J. Bayro
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520
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397
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Bermudez M, Mortier J, Rakers C, Sydow D, Wolber G. More than a look into a crystal ball: protein structure elucidation guided by molecular dynamics simulations. Drug Discov Today 2016; 21:1799-1805. [PMID: 27417339 DOI: 10.1016/j.drudis.2016.07.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 05/20/2016] [Accepted: 07/04/2016] [Indexed: 10/21/2022]
Abstract
The 'form follows function' principle implies that a structural determination of protein structures is indispensable to understand proteins in their biological roles. However, experimental methods still show shortcomings in the description of the dynamic properties of proteins. Therefore, molecular dynamics (MD) simulations represent an essential tool for structural biology to investigate proteins as flexible and dynamic entities. Here, we will give an overview on the impact of MD simulations on structural investigations, including studies that aim at a prediction of protein-folding pathways, protein-assembly processes and the sampling of conformational space by computational means.
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Affiliation(s)
- Marcel Bermudez
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Straße 2+4, 14195 Berlin, Germany.
| | - Jeremie Mortier
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Straße 2+4, 14195 Berlin, Germany
| | - Christin Rakers
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Straße 2+4, 14195 Berlin, Germany
| | - Dominique Sydow
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Straße 2+4, 14195 Berlin, Germany
| | - Gerhard Wolber
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Straße 2+4, 14195 Berlin, Germany
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398
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Singharoy A, Teo I, McGreevy R, Stone JE, Zhao J, Schulten K. Molecular dynamics-based refinement and validation for sub-5 Å cryo-electron microscopy maps. eLife 2016; 5. [PMID: 27383269 PMCID: PMC4990421 DOI: 10.7554/elife.16105] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 07/06/2016] [Indexed: 12/12/2022] Open
Abstract
Two structure determination methods, based on the molecular dynamics flexible fitting (MDFF) paradigm, are presented that resolve sub-5 Å cryo-electron microscopy (EM) maps with either single structures or ensembles of such structures. The methods, denoted cascade MDFF and resolution exchange MDFF, sequentially re-refine a search model against a series of maps of progressively higher resolutions, which ends with the original experimental resolution. Application of sequential re-refinement enables MDFF to achieve a radius of convergence of ~25 Å demonstrated with the accurate modeling of β-galactosidase and TRPV1 proteins at 3.2 Å and 3.4 Å resolution, respectively. The MDFF refinements uniquely offer map-model validation and B-factor determination criteria based on the inherent dynamics of the macromolecules studied, captured by means of local root mean square fluctuations. The MDFF tools described are available to researchers through an easy-to-use and cost-effective cloud computing resource on Amazon Web Services. DOI:http://dx.doi.org/10.7554/eLife.16105.001 To understand the roles that proteins and other large molecules play inside cells, it is important to determine their structures. One of the techniques that researchers can use to do this is called cryo-electron microscopy (cryo-EM), which rapidly freezes molecules to fix them in position before imaging them in fine detail. The cryo-EM images are like maps that show the approximate position of atoms. These images must then be processed in order to build a three-dimensional model of the protein that shows how its atoms are arranged relative to each other. One computational approach called Molecular Dynamics Flexible Fitting (MDFF) works by flexibly fitting possible atomic structures into cryo-EM maps. Although this approach works well with relatively undetailed (or ‘low resolution’) cryo-EM images, it struggles to handle the high-resolution cryo-EM maps now being generated. Singharoy, Teo, McGreevy et al. have now developed two MDFF methods – called cascade MDFF and resolution exchange MDFF – that help to resolve atomic models of biological molecules from cryo-EM images. Each method can refine poorly guessed models into ones that are consistent with the high-resolution experimental images. The refinement is achieved by interpreting a range of images that starts with a ‘fuzzy’ image. The contrast of the image is then progressively improved until an image is produced that has a resolution that is good enough to almost distinguish individual atoms. The method works because each cryo-EM image shows not just one, but a collection of atomic structures that the molecule can take on, with the fuzzier parts of the image representing the more flexible parts of the molecule. By taking into account this flexibility, the large-scale features of the protein structure can be determined first from the fuzzier images, and increasing the contrast of the images allows smaller-scale refinements to be made to the structure. The MDFF tools have been designed to be easy to use and are available to researchers at low cost through cloud computing platforms. They can now be used to unravel the structure of many different proteins and protein complexes including those involved in photosynthesis, respiration and protein synthesis. DOI:http://dx.doi.org/10.7554/eLife.16105.002
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Affiliation(s)
- Abhishek Singharoy
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, United States
| | - Ivan Teo
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, United States.,Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States
| | - Ryan McGreevy
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, United States
| | - John E Stone
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, United States
| | - Jianhua Zhao
- Department of Biochemistry and Biophysics, University of California San Francisco School of Medicine, San Francisco, United States
| | - Klaus Schulten
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, United States.,Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States
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399
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Reddy T, Sansom MSP. Computational virology: From the inside out. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1858:1610-8. [PMID: 26874202 PMCID: PMC4884666 DOI: 10.1016/j.bbamem.2016.02.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 02/05/2016] [Accepted: 02/08/2016] [Indexed: 12/23/2022]
Abstract
Viruses typically pack their genetic material within a protein capsid. Enveloped viruses also have an outer membrane made up of a lipid bilayer and membrane-spanning glycoproteins. X-ray diffraction and cryoelectron microscopy provide high resolution static views of viral structure. Molecular dynamics (MD) simulations may be used to provide dynamic insights into the structures of viruses and their components. There have been a number of simulations of viral capsids and (in some cases) of the inner core of RNA or DNA packaged within them. These simulations have generally focussed on the structural integrity and stability of the capsid and/or on the influence of the nucleic acid core on capsid stability. More recently there have been a number of simulation studies of enveloped viruses, including HIV-1, influenza A, and dengue virus. These have addressed the dynamic behaviour of the capsid, the matrix, and/or of the outer envelope. Analysis of the dynamics of the lipid bilayer components of the envelopes of influenza A and of dengue virus reveals a degree of biophysical robustness, which may contribute to the stability of virus particles in different environments. Significant computational challenges need to be addressed to aid simulation of complex viruses and their membranes, including the need to integrate structural data from a range of sources to enable us to move towards simulations of intact virions. This article is part of a Special Issue entitled: Membrane Proteins edited by J.C. Gumbart and Sergei Noskov.
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Affiliation(s)
- Tyler Reddy
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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400
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Venditti V, Egner TK, Clore GM. Hybrid Approaches to Structural Characterization of Conformational Ensembles of Complex Macromolecular Systems Combining NMR Residual Dipolar Couplings and Solution X-ray Scattering. Chem Rev 2016; 116:6305-22. [PMID: 26739383 PMCID: PMC5590664 DOI: 10.1021/acs.chemrev.5b00592] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Solving structures or structural ensembles of large macromolecular systems in solution poses a challenging problem. While NMR provides structural information at atomic resolution, increased spectral complexity, chemical shift overlap, and short transverse relaxation times (associated with slow tumbling) render application of the usual techniques that have been so successful for medium sized systems (<50 kDa) difficult. Solution X-ray scattering, on the other hand, is not limited by molecular weight but only provides low resolution structural information related to the overall shape and size of the system under investigation. Here we review how combining atomic resolution structures of smaller domains with sparse experimental data afforded by NMR residual dipolar couplings (which yield both orientational and shape information) and solution X-ray scattering data in rigid-body simulated annealing calculations provides a powerful approach for investigating the structural aspects of conformational dynamics in large multidomain proteins. The application of this hybrid methodology is illustrated for the 128 kDa dimer of bacterial Enzyme I which exists in a variety of open and closed states that are sampled at various points in the catalytic cycles, and for the capsid protein of the human immunodeficiency virus.
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Affiliation(s)
- Vincenzo Venditti
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Timothy K. Egner
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - G. Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
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