1
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Decombe A, Peersen O, Sutto-Ortiz P, Chamontin C, Piorkowski G, Canard B, Nisole S, Decroly E. Internal RNA 2'-O-methylation on the HIV-1 genome impairs reverse transcription. Nucleic Acids Res 2024; 52:1359-1373. [PMID: 38015463 PMCID: PMC10853786 DOI: 10.1093/nar/gkad1134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 11/07/2023] [Accepted: 11/09/2023] [Indexed: 11/29/2023] Open
Abstract
Viral RNA genomes are modified by epitranscriptomic marks, including 2'-O-methylation that is added by cellular or viral methyltransferases. 2'-O-Methylation modulates RNA structure, function and discrimination between self- and non-self-RNA by innate immune sensors such as RIG-I-like receptors. This is illustrated by human immunodeficiency virus type-1 (HIV-1) that decorates its RNA genome through hijacking the cellular FTSJ3 2'-O-methyltransferase, thereby limiting immune sensing and interferon production. However, the impact of such an RNA modification during viral genome replication is poorly understood. Here we show by performing endogenous reverse transcription on methylated or hypomethylated HIV-1 particles, that 2'-O-methylation negatively affects HIV-1 reverse transcriptase activity. Biochemical assays confirm that RNA 2'-O-methylation impedes reverse transcriptase activity, especially at low dNTP concentrations reflecting those in quiescent cells, by reducing nucleotide incorporation efficiency and impairing translocation. Mutagenesis highlights K70 as a critical amino acid for the reverse transcriptase to bypass 2'-O-methylation. Hence, the observed antiviral effect due to viral RNA 2'-O-methylation antagonizes the FTSJ3-mediated proviral effects, suggesting the fine-tuning of RNA methylation during viral replication.
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Affiliation(s)
- Alice Decombe
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique, Aix-Marseille Université, Marseille 13288, France
| | - Olve Peersen
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Priscila Sutto-Ortiz
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique, Aix-Marseille Université, Marseille 13288, France
| | - Célia Chamontin
- Institut de Recherche en Infectiologie de Montpellier (IRIM), Centre National de la Recherche Scientifique, Université de Montpellier, Montpellier 34090, France
| | - Géraldine Piorkowski
- Unité des Virus Émergents (UVE: Aix-Marseille Univ-IRD 190-Inserm 1207), 13005 Marseille, France
| | - Bruno Canard
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique, Aix-Marseille Université, Marseille 13288, France
| | - Sébastien Nisole
- Institut de Recherche en Infectiologie de Montpellier (IRIM), Centre National de la Recherche Scientifique, Université de Montpellier, Montpellier 34090, France
| | - Etienne Decroly
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique, Aix-Marseille Université, Marseille 13288, France
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2
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Baldwin ET, van Eeuwen T, Hoyos D, Zalevsky A, Tchesnokov EP, Sánchez R, Miller BD, Di Stefano LH, Ruiz FX, Hancock M, Işik E, Mendez-Dorantes C, Walpole T, Nichols C, Wan P, Riento K, Halls-Kass R, Augustin M, Lammens A, Jestel A, Upla P, Xibinaku K, Congreve S, Hennink M, Rogala KB, Schneider AM, Fairman JE, Christensen SM, Desrosiers B, Bisacchi GS, Saunders OL, Hafeez N, Miao W, Kapeller R, Zaller DM, Sali A, Weichenrieder O, Burns KH, Götte M, Rout MP, Arnold E, Greenbaum BD, Romero DL, LaCava J, Taylor MS. Structures, functions and adaptations of the human LINE-1 ORF2 protein. Nature 2024; 626:194-206. [PMID: 38096902 PMCID: PMC10830420 DOI: 10.1038/s41586-023-06947-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 12/07/2023] [Indexed: 01/05/2024]
Abstract
The LINE-1 (L1) retrotransposon is an ancient genetic parasite that has written around one-third of the human genome through a 'copy and paste' mechanism catalysed by its multifunctional enzyme, open reading frame 2 protein (ORF2p)1. ORF2p reverse transcriptase (RT) and endonuclease activities have been implicated in the pathophysiology of cancer2,3, autoimmunity4,5 and ageing6,7, making ORF2p a potential therapeutic target. However, a lack of structural and mechanistic knowledge has hampered efforts to rationally exploit it. We report structures of the human ORF2p 'core' (residues 238-1061, including the RT domain) by X-ray crystallography and cryo-electron microscopy in several conformational states. Our analyses identified two previously undescribed folded domains, extensive contacts to RNA templates and associated adaptations that contribute to unique aspects of the L1 replication cycle. Computed integrative structural models of full-length ORF2p show a dynamic closed-ring conformation that appears to open during retrotransposition. We characterize ORF2p RT inhibition and reveal its underlying structural basis. Imaging and biochemistry show that non-canonical cytosolic ORF2p RT activity can produce RNA:DNA hybrids, activating innate immune signalling through cGAS/STING and resulting in interferon production6-8. In contrast to retroviral RTs, L1 RT is efficiently primed by short RNAs and hairpins, which probably explains cytosolic priming. Other biochemical activities including processivity, DNA-directed polymerization, non-templated base addition and template switching together allow us to propose a revised L1 insertion model. Finally, our evolutionary analysis demonstrates structural conservation between ORF2p and other RNA- and DNA-dependent polymerases. We therefore provide key mechanistic insights into L1 polymerization and insertion, shed light on the evolutionary history of L1 and enable rational drug development targeting L1.
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Affiliation(s)
| | - Trevor van Eeuwen
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY, USA
| | - David Hoyos
- Computational Oncology, Department of Epidemiology & Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Arthur Zalevsky
- Department of Bioengineering and Therapeutic Sciences University of California, San Francisco, San Francisco, CA, USA
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
- Quantitative Biology Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Egor P Tchesnokov
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | | | - Bryant D Miller
- Department of Pathology, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
| | - Luciano H Di Stefano
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, Groningen, The Netherlands
| | - Francesc Xavier Ruiz
- Center for Advanced Biotechnology and Medicine and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, USA
| | - Matthew Hancock
- Department of Bioengineering and Therapeutic Sciences University of California, San Francisco, San Francisco, CA, USA
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
- Quantitative Biology Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Esin Işik
- Department of Pathology, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
| | - Carlos Mendez-Dorantes
- Department of Pathology, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
| | - Thomas Walpole
- Charles River Laboratories, Chesterford Research Park, Saffron Walden, UK
| | - Charles Nichols
- Charles River Laboratories, Chesterford Research Park, Saffron Walden, UK
| | - Paul Wan
- Charles River Laboratories, Chesterford Research Park, Saffron Walden, UK
| | - Kirsi Riento
- Charles River Laboratories, Chesterford Research Park, Saffron Walden, UK
| | - Rowan Halls-Kass
- Charles River Laboratories, Chesterford Research Park, Saffron Walden, UK
| | | | - Alfred Lammens
- Proteros Biostructures GmbH, Martinsried, Planegg, Germany
| | - Anja Jestel
- Proteros Biostructures GmbH, Martinsried, Planegg, Germany
| | - Paula Upla
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY, USA
| | - Kera Xibinaku
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | | | | | - Kacper B Rogala
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA
- Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Anna M Schneider
- Structural Biology of Selfish RNA, Department of Protein Evolution, Max Planck Institute for Biology, Tübingen, Germany
| | | | | | | | | | | | | | | | | | | | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences University of California, San Francisco, San Francisco, CA, USA
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
- Quantitative Biology Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Oliver Weichenrieder
- Structural Biology of Selfish RNA, Department of Protein Evolution, Max Planck Institute for Biology, Tübingen, Germany
| | - Kathleen H Burns
- Department of Pathology, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA, USA.
| | - Matthias Götte
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada.
| | - Michael P Rout
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY, USA.
| | - Eddy Arnold
- Center for Advanced Biotechnology and Medicine and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, USA.
| | - Benjamin D Greenbaum
- Computational Oncology, Department of Epidemiology & Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Physiology, Biophysics & Systems Biology, Weill Cornell Medicine, Weill Cornell Medical College, New York, NY, USA.
| | | | - John LaCava
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY, USA.
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, Groningen, The Netherlands.
| | - Martin S Taylor
- Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
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3
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Levintov L, Vashisth H. Structural and computational studies of HIV-1 RNA. RNA Biol 2024; 21:1-32. [PMID: 38100535 PMCID: PMC10730233 DOI: 10.1080/15476286.2023.2289709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2023] [Indexed: 12/17/2023] Open
Abstract
Viruses remain a global threat to animals, plants, and humans. The type 1 human immunodeficiency virus (HIV-1) is a member of the retrovirus family and carries an RNA genome, which is reverse transcribed into viral DNA and further integrated into the host-cell DNA for viral replication and proliferation. The RNA structures from the HIV-1 genome provide valuable insights into the mechanisms underlying the viral replication cycle. Moreover, these structures serve as models for designing novel therapeutic approaches. Here, we review structural data on RNA from the HIV-1 genome as well as computational studies based on these structural data. The review is organized according to the type of structured RNA element which contributes to different steps in the viral replication cycle. This is followed by an overview of the HIV-1 transactivation response element (TAR) RNA as a model system for understanding dynamics and interactions in the viral RNA systems. The review concludes with a description of computational studies, highlighting the impact of biomolecular simulations in elucidating the mechanistic details of various steps in the HIV-1's replication cycle.
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Affiliation(s)
- Lev Levintov
- Department of Chemical Engineering & Bioengineering, University of New Hampshire, Durham, USA
| | - Harish Vashisth
- Department of Chemical Engineering & Bioengineering, University of New Hampshire, Durham, USA
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4
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Vergara S, Zhou X, Santiago U, Conway JF, Sluis-Cremer N, Calero G. Structures of kinetic intermediate states of HIV-1 reverse transcriptase DNA synthesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.18.572243. [PMID: 38187617 PMCID: PMC10769260 DOI: 10.1101/2023.12.18.572243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Reverse transcription of the retroviral single-stranded RNA into double-stranded DNA is an integral step during HIV-1 replication, and reverse transcriptase (RT) is a primary target for antiviral therapy. Despite a wealth of structural information on RT, we lack critical insight into the intermediate kinetic states of DNA synthesis. Using catalytically active substrates, and a novel blot/diffusion cryo-electron microscopy approach, we captured 11 structures that define the substrate binding, reactant, transition and product states of dATP addition by RT at 1.9 to 2.4 Å resolution in the active site. Initial dATP binding to RT-template/primer complex involves a single Mg 2+ (site B), and promotes partial closure of the active site pocket by a large conformational change in the β3-β4 loop in the Fingers domain, and formation of a negatively charged pocket where a second "drifting" Mg 2+ can bind (site A). During the transition state, the α-phosphate oxygen from a previously unobserved dATP conformer aligns with the site A Mg 2+ and the primer 3'-OH for nucleophilic attack. In the product state, we captured two substrate conformations in the active site: 1) dATP that had yet to be incorporated into the nascent DNA, and 2) an incorporated dAMP with the pyrophosphate leaving group coordinated by metal B and stabilized through H- bonds in the active site of RT. This study provides insights into a fundamental chemical reaction that impacts polymerase fidelity, nucleoside inhibitor drug design, and mechanisms of drug resistance.
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5
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Seetaha S, Kamonsutthipaijit N, Yagi-Utsumi M, Seako Y, Yamaguchi T, Hannongbua S, Kato K, Choowongkomon K. Biophysical Characterization of p51 and p66 Monomers of HIV-1 Reverse Transcriptase with Their Inhibitors. Protein J 2023; 42:741-752. [PMID: 37728788 DOI: 10.1007/s10930-023-10156-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2023] [Indexed: 09/21/2023]
Abstract
Human immunodeficiency virus (HIV)-1 reverse transcriptase (HIV-1 RT) is responsible for the transcription of viral RNA genomes into DNA genomes and has become an important target for the treatment of acquired immune deficiency syndrome (AIDS). This study used biophysical techniques to characterize the HIV-1 RT structure, monomer forms, and the non-nucleoside reverse transcriptase inhibitors (NNRTIs) bound forms. Inactive p66W401A and p51W401A were selected as models to study the HIV-1 RT monomer structures. Nuclear magnetic resonance (NMR) spectroscopy revealed that the unliganded forms of p66W401A protein and p51W401A protein had similar conformation to each other in solution. The complexes of p66W401A or p51W401A with inhibitors showed similar conformations to p66 in the RT heterodimer bound to the NNRTIs. Furthermore, the results of paramagnetic relaxation enhancement (PRE)-assisted NMR revealed that the unliganded forms of the p66W401A and p51W401A conformations were different from the unliganded heterodimer, characterized by a greater distance between the fingers and thumb subdomains. Small-angle X-ray scattering (SAXS) experiments confirmed that p66W401A and p51W401A can bind with inhibitors, similar to the p66/p51 heterodimer. The findings of this study increase the structural knowledge base of HIV-1 RT monomers, which may be helpful in the future design of potent viral inhibitors.
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Affiliation(s)
- Supaphorn Seetaha
- KU Institute for Advanced Studies, Kasetsart University, Bangkok, 10900, Thailand
- Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Nuntaporn Kamonsutthipaijit
- Synchrotron Light Research Institute, 111 University Avenue, Muang District, Nakhon Ratchasima, 30000, Thailand
| | - Maho Yagi-Utsumi
- Exploratory Research Center on Life and Living Systems, Okazaki, Aichi, Japan
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Aichi, Japan
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi, Japan
| | - Yanaka Seako
- Exploratory Research Center on Life and Living Systems, Okazaki, Aichi, Japan
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Aichi, Japan
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi, Japan
| | - Takumi Yamaguchi
- Exploratory Research Center on Life and Living Systems, Okazaki, Aichi, Japan
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Aichi, Japan
| | - Supa Hannongbua
- Department of Chemistry, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand
| | - Koichi Kato
- Exploratory Research Center on Life and Living Systems, Okazaki, Aichi, Japan
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Aichi, Japan
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi, Japan
| | - Kiattawee Choowongkomon
- KU Institute for Advanced Studies, Kasetsart University, Bangkok, 10900, Thailand.
- Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand.
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6
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Srivastava R, Gupta SK, Naaz F, Sen Gupta PS, Yadav M, Singh VK, Panda SK, Biswal S, Rana MK, Gupta SK, Schols D, Singh RK. Exploring antiviral potency of N-1 substituted pyrimidines against HIV-1 and other DNA/RNA viruses: Design, synthesis, characterization, ADMET analysis, docking, molecular dynamics and biological activity. Comput Biol Chem 2023; 106:107910. [PMID: 37422940 DOI: 10.1016/j.compbiolchem.2023.107910] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 06/16/2023] [Accepted: 06/25/2023] [Indexed: 07/11/2023]
Abstract
A novel series of pyrimidine derivatives, bearing modified benzimidazoles at N-1 position, has been designed, synthesized and screened as NNRTIs against HIV and as broad-spectrum antiviral agents. The molecules were screened against different HIV targets using molecular docking experiment. The docking results indicated that the molecules interacted well with the residues Lys101, Tyr181, Tyr188, Trp229, Phe227 and Tyr318 present in NNIBP of HIV-RT protein, formed quite stable complexes and, thus, behaved as probable NNRTIs. Among these compounds, 2b and 4b showed anti-HIV activity with IC50 values as 6.65 µg/mL (SI = 15.50) and 15.82 µg/mL (SI = 14.26), respectively. Similarly, compound 1a showed inhibitory property against coxsackie virus B4 and compound 3b against different viruses. Molecular dynamics simulation results unequivocally demonstrated the higher stability of the complex HIV-RT:2b than the HIV-RT:nevirapine complex. The MM/PBSA-based binding free energy (-) 114.92 kJ/mol of HIV-RT:2b complex in comparison to that of HIV-RT:nevirapine complex (-) 88.33 kJ/mol, further demonstrated the higher binding strength of 2b and thus, established the potential of compound 2b as a lead molecule as an HIV-RT inhibitor.
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Affiliation(s)
- Ritika Srivastava
- Bioorganic Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad 211002, India; Department of Chemical Sciences, Indian Institute of Science Education and Research Berhampur, Odisha 760010, India
| | - Sunil K Gupta
- Bioorganic Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad 211002, India
| | - Farha Naaz
- Bioorganic Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad 211002, India
| | - Parth Sarthi Sen Gupta
- School of Biosciences and Bioengineering, D Y Patil International University, Akurdi, Pune, India
| | - Madhu Yadav
- Bioorganic Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad 211002, India
| | - Vishal Kumar Singh
- Bioorganic Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad 211002, India
| | - Saroj Kumar Panda
- Department of Chemical Sciences, Indian Institute of Science Education and Research Berhampur, Odisha 760010, India
| | - Satyaranjan Biswal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Berhampur, Odisha 760010, India
| | - Malay Kumar Rana
- Department of Chemical Sciences, Indian Institute of Science Education and Research Berhampur, Odisha 760010, India
| | | | | | - Ramendra K Singh
- Bioorganic Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad 211002, India.
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7
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Das CK, Gupta A, Nair NN. Probing the general base for DNA polymerization in telomerase: a molecular dynamics investigation. Phys Chem Chem Phys 2023; 25:14147-14157. [PMID: 37162325 DOI: 10.1039/d3cp00521f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Telomerase is an RNA-dependent DNA polymerase that plays a role in the maintenance of the 3' end of the eukaryotic chromosome, known as a telomere, by catalyzing the DNA polymerization reaction in cancer and embryonic stem cells. The detailed molecular details of the DNA polymerization by telomerase, especially the general base for deprotonating the terminal 3'-hydroxyl, which triggers the chemical reaction, remain elusive. We conducted a computational investigation using hybrid quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) simulations to probe the detailed mechanism of the reaction. Our simulations started with the telomerase:RNA:DNA:dNTP ternary complex, and by using enhanced sampling QM/MM MD simulations, we probed the general base involved directly in the polymerization. We report the participation of an aspartate (Asp344) coordinated to Mg and an active site water molecule, jointly acting as a base during nucleic acid addition. The Asp344 residue remains transiently protonated during the course of the reaction, and later it deprotonates by transferring its proton to the water at the end of the reaction.
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Affiliation(s)
- Chandan Kumar Das
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
| | - Abhinav Gupta
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
| | - Nisanth N Nair
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
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8
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Figiel M, Gapińska M, Czarnocki-Cieciura M, Zajko W, Sroka M, Skowronek K, Nowotny M. Mechanism of protein-primed template-independent DNA synthesis by Abi polymerases. Nucleic Acids Res 2022; 50:10026-10040. [PMID: 36107766 PMCID: PMC9508834 DOI: 10.1093/nar/gkac772] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 08/23/2022] [Accepted: 08/30/2022] [Indexed: 11/20/2022] Open
Abstract
Abortive infection (Abi) is a bacterial antiphage defense strategy involving suicide of the infected cell. Some Abi pathways involve polymerases that are related to reverse transcriptases. They are unique in the way they combine the ability to synthesize DNA in a template-independent manner with protein priming. Here, we report crystal and cryo-electron microscopy structures of two Abi polymerases: AbiK and Abi-P2. Both proteins adopt a bilobal structure with an RT-like domain that comprises palm and fingers subdomains and a unique helical domain. AbiK and Abi-P2 adopt a hexameric and trimeric configuration, respectively, which is unprecedented for reverse transcriptases. Biochemical experiments showed that the formation of these oligomers is required for the DNA polymerization activity. The structure of the AbiK–DNA covalent adduct visualized interactions between the 3′ end of DNA and the active site and covalent attachment of the 5′ end of DNA to a tyrosine residue used for protein priming. Our data reveal a structural basis of the mechanism of highly unusual template-independent protein-priming polymerases.
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Affiliation(s)
- Małgorzata Figiel
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology , Warsaw , Poland
| | - Marta Gapińska
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology , Warsaw , Poland
| | - Mariusz Czarnocki-Cieciura
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology , Warsaw , Poland
| | - Weronika Zajko
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology , Warsaw , Poland
| | - Małgorzata Sroka
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology , Warsaw , Poland
| | - Krzysztof Skowronek
- Biophysics and Bioanalytics Facility, International Institute of Molecular and Cell Biology , Warsaw , Poland
| | - Marcin Nowotny
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology , Warsaw , Poland
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9
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Cryo-EM structures of Escherichia coli Ec86 retron complexes reveal architecture and defence mechanism. Nat Microbiol 2022; 7:1480-1489. [PMID: 35982312 DOI: 10.1038/s41564-022-01197-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 07/05/2022] [Indexed: 11/09/2022]
Abstract
First discovered in the 1980s, retrons are bacterial genetic elements consisting of a reverse transcriptase and a non-coding RNA (ncRNA). Retrons mediate antiphage defence in bacteria but their structure and defence mechanisms are unknown. Here, we investigate the Escherichia coli Ec86 retron and use cryo-electron microscopy to determine the structures of the Ec86 (3.1 Å) and cognate effector-bound Ec86 (2.5 Å) complexes. The Ec86 reverse transcriptase exhibits a characteristic right-hand-like fold consisting of finger, palm and thumb subdomains. Ec86 reverse transcriptase reverse-transcribes part of the ncRNA into satellite, multicopy single-stranded DNA (msDNA, a DNA-RNA hybrid) that we show wraps around the reverse transcriptase electropositive surface. In msDNA, both inverted repeats are present and the 3' sides of the DNA/RNA chains are close to the reverse transcriptase active site. The Ec86 effector adopts a two-lobe fold and directly binds reverse transcriptase and msDNA. These findings offer insights into the structure-function relationship of the retron-effector unit and provide a structural basis for the optimization of retron-based genome editing systems.
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10
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Insights into HIV-1 Reverse Transcriptase (RT) Inhibition and Drug Resistance from Thirty Years of Structural Studies. Viruses 2022; 14:v14051027. [PMID: 35632767 PMCID: PMC9148108 DOI: 10.3390/v14051027] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 02/01/2023] Open
Abstract
The enzyme reverse transcriptase (RT) plays a central role in the life cycle of human immunodeficiency virus (HIV), and RT has been an important drug target. Elucidations of the RT structures trapping and detailing the enzyme at various functional and conformational states by X-ray crystallography have been instrumental for understanding RT activities, inhibition, and drug resistance. The structures have contributed to anti-HIV drug development. Currently, two classes of RT inhibitors are in clinical use. These are nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs). However, the error-prone viral replication generates variants that frequently develop resistance to the available drugs, thus warranting a continued effort to seek more effective treatment options. RT also provides multiple additional potential druggable sites. Recently, the use of single-particle cryogenic electron microscopy (cryo-EM) enabled obtaining structures of NNRTI-inhibited HIV-1 RT/dsRNA initiation and RT/dsDNA elongation complexes that were unsuccessful by X-ray crystallography. The cryo-EM platform for the structural study of RT has been established to aid drug design. In this article, we review the roles of structural biology in understanding and targeting HIV RT in the past three decades and the recent structural insights of RT, using cryo-EM.
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11
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Flexibility of telomerase in binding the RNA template and DNA telomeric repeat. Proc Natl Acad Sci U S A 2022; 119:2116159118. [PMID: 34969861 PMCID: PMC8740718 DOI: 10.1073/pnas.2116159118] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/22/2021] [Indexed: 12/12/2022] Open
Abstract
Telomerase reverse transcriptase (TERT) has a conserved central cavity near the active site. Using enzymatic and mutagenesis analyses, we provide experimental evidence that an artificially looped-out telomeric repeat in the DNA primer can be transiently accommodated in the cavity of Tribolium castaneum (tcTERT). Kinetically, tcTERT requires a minimum of 4 bp between the RNA template and DNA primer for efficient DNA synthesis. An RNA duplex downstream of the RNA-template region after a flexible linker enhances the efficiency of primer extension by tcTERT. In addition to the peripheral cavities that accommodate looped-out RNA during each telomeric repeat synthesis, the central cavity that can accommodate the looped-out DNA may aid RNA-template translocation between cycles of telomeric repeat synthesis. Telomerase synthesizes telomeres at the ends of linear chromosomes by repeated reverse transcription from a short RNA template. Crystal structures of Tribolium castaneum telomerase reverse transcriptase (tcTERT) and cryoelectron microscopy (cryo-EM) structures of human and Tetrahymena telomerase have revealed conserved features in the reverse-transcriptase domain, including a cavity near the DNA 3′ end and snug interactions with the RNA template. For the RNA template to translocate, it needs to be unpaired and separated from the DNA product. Here we investigate the potential of the structural cavity to accommodate a looped-out DNA bulge and enable the separation of the RNA/DNA hybrid. Using tcTERT as a model system, we show that a looped-out telomeric repeat in the DNA primer can be accommodated and extended by tcTERT but not by retroviral reverse transcriptase. Mutations that reduce the cavity size reduce the ability of tcTERT to extend the looped-out DNA substrate. In agreement with cryo-EM structures of telomerases, we find that tcTERT requires a minimum of 4 bp between the RNA template and DNA primer for efficient DNA synthesis. We also have determined the ternary-complex structure of tcTERT including a downstream RNA/DNA hybrid at 2.0-Å resolution and shown that a downstream RNA duplex, equivalent to the 5′ template-boundary element in telomerase RNA, enhances the efficiency of telomere synthesis by tcTERT. Although TERT has a preformed active site without the open-and-closed conformational changes, it contains cavities to accommodate looped-out RNA and DNA. The flexible RNA–DNA binding likely underlies the processivity of telomeric repeat addition.
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12
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Ilina TV, Brosenitsch T, Sluis-Cremer N, Ishima R. Retroviral RNase H: Structure, mechanism, and inhibition. Enzymes 2021; 50:227-247. [PMID: 34861939 DOI: 10.1016/bs.enz.2021.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
All retroviruses encode the enzyme, reverse transcriptase (RT), which is involved in the conversion of the single-stranded viral RNA genome into double-stranded DNA. RT is a multifunctional enzyme and exhibits DNA polymerase and ribonuclease H (RNH) activities, both of which are essential to the reverse-transcription process. Despite the successful development of polymerase-targeting antiviral drugs over the last three decades, no bona fide inhibitor against the RNH activity of HIV-1 RT has progressed to clinical evaluation. In this review article, we describe the retroviral RNH function and inhibition, with primary consideration of the structural aspects of inhibition.
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Affiliation(s)
- Tatiana V Ilina
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Teresa Brosenitsch
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Nicolas Sluis-Cremer
- Department of Medicine, Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Rieko Ishima
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States.
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13
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Abstract
Reverse transcriptases (RTs) use their DNA polymerase and RNase H activities to catalyze the conversion of single-stranded RNA to double-stranded DNA (dsDNA), a crucial process for the replication of retroviruses. Foamy viruses (FVs) possess a unique RT, which is a fusion with the protease (PR) domain. The mechanism of substrate binding by this enzyme has been unknown. Here, we report a crystal structure of monomeric full-length marmoset FV (MFV) PR-RT in complex with an RNA/DNA hybrid substrate. We also describe a structure of MFV PR-RT with an RNase H deletion in complex with a dsDNA substrate in which the enzyme forms an asymmetric homodimer. Cryo-electron microscopy reconstruction of the full-length MFV PR-RT–dsDNA complex confirmed the dimeric architecture. These findings represent the first structural description of nucleic acid binding by a foamy viral RT and demonstrate its ability to change its oligomeric state depending on the type of bound nucleic acid. IMPORTANCE Reverse transcriptases (RTs) are intriguing enzymes converting single-stranded RNA to dsDNA. Their activity is essential for retroviruses, which are divided into two subfamilies differing significantly in their life cycles: Orthoretrovirinae and Spumaretrovirinae. The latter family is much more ancient and comprises five genera. A unique feature of foamy viral RTs is that they contain N-terminal protease (PR) domains, which are not present in orthoretroviral enzymes. So far, no structural information for full-length foamy viral PR-RT interacting with nucleic substrates has been reported. Here, we present crystal and cryo-electron microscopy structures of marmoset foamy virus (MFV) PR-RT. These structures revealed the mode of binding of RNA/DNA and dsDNA substrates. Moreover, unexpectedly, the structures and biochemical data showed that foamy viral PR-RT can adopt both a monomeric configuration, which is observed in our structures in the presence of an RNA/DNA hybrid, and an asymmetric dimer arrangement, which we observed in the presence of dsDNA.
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14
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Structural basis for template switching by a group II intron-encoded non-LTR-retroelement reverse transcriptase. J Biol Chem 2021; 297:100971. [PMID: 34280434 PMCID: PMC8363836 DOI: 10.1016/j.jbc.2021.100971] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 06/30/2021] [Accepted: 07/15/2021] [Indexed: 12/02/2022] Open
Abstract
Reverse transcriptases (RTs) can switch template strands during complementary DNA synthesis, enabling them to join discontinuous nucleic acid sequences. Template switching (TS) plays crucial roles in retroviral replication and recombination, is used for adapter addition in RNA-Seq, and may contribute to retroelement fitness by increasing evolutionary diversity and enabling continuous complementary DNA synthesis on damaged templates. Here, we determined an X-ray crystal structure of a TS complex of a group II intron RT bound simultaneously to an acceptor RNA and donor RNA template–DNA primer heteroduplex with a 1-nt 3′-DNA overhang. The structure showed that the 3′ end of the acceptor RNA binds in a pocket formed by an N-terminal extension present in non–long terminal repeat–retroelement RTs and the RT fingertips loop, with the 3′ nucleotide of the acceptor base paired to the 1-nt 3′-DNA overhang and its penultimate nucleotide base paired to the incoming dNTP at the RT active site. Analysis of structure-guided mutations identified amino acids that contribute to acceptor RNA binding and a phenylalanine residue near the RT active site that mediates nontemplated nucleotide addition. Mutation of the latter residue decreased multiple sequential template switches in RNA-Seq. Our results provide new insights into the mechanisms of TS and nontemplated nucleotide addition by RTs, suggest how these reactions could be improved for RNA-Seq, and reveal common structural features for TS by non–long terminal repeat–retroelement RTs and viral RNA–dependent RNA polymerases.
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15
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Structural coordination between active sites of a CRISPR reverse transcriptase-integrase complex. Nat Commun 2021; 12:2571. [PMID: 33958590 PMCID: PMC8102632 DOI: 10.1038/s41467-021-22900-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 03/26/2021] [Indexed: 02/03/2023] Open
Abstract
CRISPR-Cas systems provide adaptive immunity in bacteria and archaea, beginning with integration of foreign sequences into the host CRISPR genomic locus and followed by transcription and maturation of CRISPR RNAs (crRNAs). In some CRISPR systems, a reverse transcriptase (RT) fusion to the Cas1 integrase and Cas6 maturase creates a single protein that enables concerted sequence integration and crRNA production. To elucidate how the RT-integrase organizes distinct enzymatic activities, we present the cryo-EM structure of a Cas6-RT-Cas1-Cas2 CRISPR integrase complex. The structure reveals a heterohexamer in which the RT directly contacts the integrase and maturase domains, suggesting functional coordination between all three active sites. Together with biochemical experiments, our data support a model of sequential enzymatic activities that enable CRISPR sequence acquisition from RNA and DNA substrates. These findings highlight an expanded capacity of some CRISPR systems to acquire diverse sequences that direct CRISPR-mediated interference.
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16
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Gu W, Martinez S, Nguyen H, Xu H, Herdewijn P, De Jonghe S, Das K. Tenofovir-Amino Acid Conjugates Act as Polymerase Substrates-Implications for Avoiding Cellular Phosphorylation in the Discovery of Nucleotide Analogues. J Med Chem 2020; 64:782-796. [PMID: 33356231 DOI: 10.1021/acs.jmedchem.0c01747] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Nucleotide analogues are used for treating viral infections such as HIV, hepatitis B, hepatitis C, influenza, and SARS-CoV-2. To become polymerase substrates, a nucleotide analogue must be phosphorylated by cellular kinases which is rate-limiting. The goal of this study is to develop dNTP/NTP analogues directly from nucleotides. Tenofovir (TFV) analogues were synthesized by conjugating with amino acids. We demonstrate that some conjugates act as dNTP analogues and HIV-1 reverse transcriptase (RT) catalytically incorporates the TFV part as the chain terminator. X-ray structures in complex with HIV-1 RT/dsDNA showed binding of the conjugates at the polymerase active site, however, in different modes in the presence of Mg2+ versus Mn2+ ions. The adaptability of the compounds is seemingly essential for catalytic incorporation of TFV by RT. 4d with a carboxyl sidechain demonstrated the highest incorporation. 4e showed weak incorporation and rather behaved as a dNTP-competitive inhibitor. This result advocates the feasibility of designing NTP/dNTP analogues by chemical substitutions to nucleotide analogues.
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Affiliation(s)
- Weijie Gu
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, Herestraat 49, 3000 Leuven, Belgium.,KU Leuven, Department of Pharmaceutical and Pharmacological Sciences, Laboratory of Medicinal Chemistry, Rega Institute for Medical Research, Herestraat 49, 3000 Leuven, Belgium
| | - Sergio Martinez
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, Herestraat 49, 3000 Leuven, Belgium
| | - Hoai Nguyen
- KU Leuven, Department of Pharmaceutical and Pharmacological Sciences, Laboratory of Medicinal Chemistry, Rega Institute for Medical Research, Herestraat 49, 3000 Leuven, Belgium
| | - Hongtao Xu
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, Herestraat 49, 3000 Leuven, Belgium
| | - Piet Herdewijn
- KU Leuven, Department of Pharmaceutical and Pharmacological Sciences, Laboratory of Medicinal Chemistry, Rega Institute for Medical Research, Herestraat 49, 3000 Leuven, Belgium
| | - Steven De Jonghe
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, Herestraat 49, 3000 Leuven, Belgium
| | - Kalyan Das
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, Herestraat 49, 3000 Leuven, Belgium
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17
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Krupkin M, Jackson LN, Ha B, Puglisi EV. Advances in understanding the initiation of HIV-1 reverse transcription. Curr Opin Struct Biol 2020; 65:175-183. [PMID: 32916568 PMCID: PMC9973426 DOI: 10.1016/j.sbi.2020.07.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/12/2020] [Accepted: 07/21/2020] [Indexed: 01/18/2023]
Abstract
Many viruses, including Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and Human Immunodeficiency Virus (HIV), use RNA as their genetic material. How viruses harness RNA structure and RNA-protein interactions to control their replication remains obscure. Recent advances in the characterization of HIV-1 reverse transcriptase, the enzyme that converts its single-stranded RNA genome into a double-stranded DNA copy, reveal how the reverse transcription complex evolves during initiation. Here we highlight these advances in HIV-1 structural biology and discuss how they are furthering our understanding of HIV and related ribonucleoprotein complexes implicated in viral disease.
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Affiliation(s)
- Miri Krupkin
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lynnette Nthenya Jackson
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Betty Ha
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA,Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Elisabetta Viani Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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18
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Tuske S, Zheng J, Olson ED, Ruiz FX, Pascal BD, Hoang A, Bauman JD, Das K, DeStefano JJ, Musier-Forsyth K, Griffin PR, Arnold E. Integrative structural biology studies of HIV-1 reverse transcriptase binding to a high-affinity DNA aptamer. Curr Res Struct Biol 2020; 2:116-129. [PMID: 33870216 PMCID: PMC8052095 DOI: 10.1016/j.crstbi.2020.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 06/03/2020] [Accepted: 06/19/2020] [Indexed: 02/07/2023] Open
Abstract
The high-resolution crystal structure of HIV-1 reverse transcriptase (RT) bound to a 38-mer DNA hairpin aptamer with low pM affinity was previously described. The high-affinity binding aptamer contained 2'-O-methyl modifications and a seven base-pair GC-rich tract and the structure of the RT-aptamer complex revealed specific contacts between RT and the template strand of the aptamer. Similar to all crystal structures of RT bound to nucleic acid template-primers, the aptamer bound RT with a bend in the duplex DNA. To understand the structural basis for the ultra-high-affinity aptamer binding, an integrative structural biology approach was used. Hydrogen-deuterium exchange coupled to liquid chromatography-mass spectrometry (HDX-MS) was used to examine the structural dynamics of RT alone and in the presence of the DNA aptamer. RT was selectively labeled with 15N to unambiguously identify peptides from each subunit. HDX of unliganded RT shows a mostly stable core. The p66 fingers and thumb subdomains, and the RNase H domain are relatively dynamic. HDX indicates that both the aptamer and a scrambled version significantly stabilize regions of RT that are dynamic in the absence of DNA. No substantial differences in RT dynamics are observed between aptamer and scrambled aptamer binding, despite a large difference in binding affinity. Small-angle X-ray scattering and circular dichroism spectroscopy were used to investigate the aptamer conformation in solution and revealed a pre-bent DNA that possesses both A- and B-form helical character. Both the 2'-O-methyl modifications and the GC tract appear to contribute to an energetically favorable conformation for binding to RT that contributes to the aptamer's ultra-high affinity for RT. The X-ray structure of RT with an RNA/DNA version of the aptamer at 2.8 Å resolution revealed a potential role of the hairpin positioning in affinity. Together, the data suggest that both the 2'-O-methyl modifications and the GC tract contribute to an energetically favorable conformation for high-affinity binding to RT.
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Affiliation(s)
- Steve Tuske
- Center for Advanced Biotechnology and Medicine, And Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, 08854, USA
| | - Jie Zheng
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL, 33458, USA
| | - Erik D. Olson
- Department of Chemistry and Biochemistry, Center for RNA Biology, And Center for Retrovirus Research, The Ohio State University, Columbus, OH, 43210, USA
| | - Francesc X. Ruiz
- Center for Advanced Biotechnology and Medicine, And Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, 08854, USA
| | - Bruce D. Pascal
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL, 33458, USA
| | - Anthony Hoang
- Center for Advanced Biotechnology and Medicine, And Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, 08854, USA
| | - Joseph D. Bauman
- Center for Advanced Biotechnology and Medicine, And Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, 08854, USA
| | - Kalyan Das
- Center for Advanced Biotechnology and Medicine, And Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, 08854, USA
| | - Jeffrey J. DeStefano
- Department of Cell Biology and Molecular Genetics, University of Maryland College Park, College Park, MD, 20740, USA
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, Center for RNA Biology, And Center for Retrovirus Research, The Ohio State University, Columbus, OH, 43210, USA
| | - Patrick R. Griffin
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL, 33458, USA
| | - Eddy Arnold
- Center for Advanced Biotechnology and Medicine, And Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, 08854, USA
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19
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Kladwang W, Topkar VV, Liu B, Rangan R, Hodges TL, Keane SC, Al-Hashimi H, Das R. Anomalous Reverse Transcription through Chemical Modifications in Polyadenosine Stretches. Biochemistry 2020; 59:2154-2170. [PMID: 32407625 DOI: 10.1021/acs.biochem.0c00020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Thermostable reverse transcriptases are workhorse enzymes underlying nearly all modern techniques for RNA structure mapping and for the transcriptome-wide discovery of RNA chemical modifications. Despite their wide use, these enzymes' behaviors at chemical modified nucleotides remain poorly understood. Wellington-Oguri et al. recently reported an apparent loss of chemical modification within putatively unstructured polyadenosine stretches modified by dimethyl sulfate or 2' hydroxyl acylation, as probed by reverse transcription. Here, reanalysis of these and other publicly available data, capillary electrophoresis experiments on chemically modified RNAs, and nuclear magnetic resonance spectroscopy on (A)12 and variants show that this effect is unlikely to arise from an unusual structure of polyadenosine. Instead, tests of different reverse transcriptases on chemically modified RNAs and molecules synthesized with single 1-methyladenosines implicate a previously uncharacterized reverse transcriptase behavior: near-quantitative bypass through chemical modifications within polyadenosine stretches. All tested natural and engineered reverse transcriptases (MMLV; SuperScript II, III, and IV; TGIRT-III; and MarathonRT) exhibit this anomalous bypass behavior. Accurate DMS-guided structure modeling of the polyadenylated HIV-1 3' untranslated region requires taking into account this anomaly. Our results suggest that poly(rA-dT) hybrid duplexes can trigger an unexpectedly effective reverse transcriptase bypass and that chemical modifications in mRNA poly(A) tails may be generally undercounted.
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Affiliation(s)
- Wipapat Kladwang
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Ved V Topkar
- Biophysics Program, Stanford University, Stanford, California 94305, United States
| | - Bei Liu
- Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710, United States
| | - Ramya Rangan
- Biophysics Program, Stanford University, Stanford, California 94305, United States
| | - Tracy L Hodges
- Biophysics Program, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Sarah C Keane
- Biophysics Program, University of Michigan, Ann Arbor, Michigan 48109, United States.,Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Hashim Al-Hashimi
- Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710, United States.,Department of Chemistry, Duke University School of Medicine, Durham, North Carolina 27710, United States
| | - Rhiju Das
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305, United States.,Biophysics Program, Stanford University, Stanford, California 94305, United States.,Department of Physics, Stanford University, Stanford, California 94305, United States
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20
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Kammarabutr J, Mahalapbutr P, Okumura H, Wolschann P, Rungrotmongkol T. Structural dynamics and susceptibility of anti-HIV drugs against HBV reverse transcriptase. J Biomol Struct Dyn 2020; 39:2502-2511. [PMID: 32308149 DOI: 10.1080/07391102.2020.1751715] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Hepatitis B virus (HBV), a small enveloped DNA virus, attacks the human liver causing both acute and chronic diseases. Current therapeutic drugs use the nucleos(t)ide analogues (NAs) as a competitive inhibitor against HBV reverse transcriptase (HBV-RT), an essential enzyme pivotally involved in viral replication. Unfortunately, this treatment still causes the development of resistant variants of HBV against NAs. As HBV-RT is homologous to the human immunodeficiency virus reverse transcriptase (HIV-RT), it is reasonable to treat HBV-RT with anti-HIV drugs. In the present study, we aimed to investigate the structural dynamics and susceptibility of the known anti-HIV drugs (stavudine [d4T], didanosine [DDI], and zidovudine [ZDV]) against HBV-RT enzyme in comparison to the anti-HBV drug lamivudine (3TC) and deoxythymidine triphosphate (dTTP) substrate using several computational approaches. The ΔGbindresidue calculations revealed that seven polar residues (K32, R41, D83, S85, D205, N236, and K239) and three hydrophobic residues (A86, A87, and F88) of HBV-RT as well as the adjacent DNA strands play an important role in the ligand binding. In addition, the H-bond pattern of d4T is similar to that of 3TC, especially at the residues A86 and A87. Such interactions promote the favorable conformation of ligand in the HBV-RT binding pocket, while the several different conformations of ligand are found in the unbound state. The predicted binding free energy results based on QM/MM-GBSA and MM/GB(PB)SA methods suggested that the susceptibility towards HBV-RT of d4T and ZDV is higher than that of 3TC and dTTP. Altogether, this work sheds light on the potentiality of d4T and ZDV as a promising drug for HBV-infected patients harboring 3TC resistance.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Jirayu Kammarabutr
- Structural and Computational Biology Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Pathumwan, Bangkok, Thailand
| | - Panupong Mahalapbutr
- Structural and Computational Biology Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Pathumwan, Bangkok, Thailand
| | - Hisashi Okumura
- Institute for Molecular Science, Research Center for Computational Science, Okazaki, Japan.,Department of Structural Molecular Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Japan
| | - Peter Wolschann
- Department of Pharmaceutical Chemistry, Faculty of Life Sciences, University of Vienna, Vienna, Austria.,Institute of Theoretical Chemistry, University of Vienna, Vienna, Austria
| | - Thanyada Rungrotmongkol
- Structural and Computational Biology Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Pathumwan, Bangkok, Thailand.,Program in Bioinformatics and Computational Biology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
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21
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Wang L, Sarafianos SG, Wang Z. Cutting into the Substrate Dominance: Pharmacophore and Structure-Based Approaches toward Inhibiting Human Immunodeficiency Virus Reverse Transcriptase-Associated Ribonuclease H. Acc Chem Res 2020; 53:218-230. [PMID: 31880912 DOI: 10.1021/acs.accounts.9b00450] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Human immunodeficiency virus (HIV) reverse transcriptase (RT) contains two distinct functional domains: a DNA polymerase (pol) domain and a ribonuclease H (RNase H) domain, both of which are required for viral genome replication. Over the last 3 decades, RT has been at the forefront of HIV drug discovery efforts with numerous nucleoside reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs) approved by the FDA. However, all these RT inhibitors target only the pol function, and inhibitors of RT-associated RNase H have yet to enter the development pipeline, which in itself manifests both the opportunity and challenges of targeting RNase H: if developed, RT RNase H inhibitors would represent a mechanistically novel class of HIV drugs that can be particularly valuable in treating HIV strains resistant to current drugs. The challenges include (1) the difficulty in selectively targeting RT RNase H over RT pol due to their close interplay both spatially and temporally and over HIV-1 integrase strand transfer (INST) activity because of their active site similarities; (2) to a larger extent, the inability of active site inhibitors to confer significant antiviral effect, presumably due to a steep substrate barrier by which the pre-existing substrate prevents access of small molecules to the active site. As a result, previously reported RT RNase H inhibitors typically lacked target specificity and significant antiviral potency. Achieving meaningful antiviral activity via active site targeting likely entails selective and ultrapotent RNase H inhibition to allow small molecules to cut into the dominance of substrates. Based on a pharmacophore model informed by prior work, we designed and redesigned a few metal-chelating chemotypes, such as 2-hydroxyisoquinolinedione (HID), hydroxypyridonecarboxylic acid (HPCA), 3-hydroxypyrimidine-2,4-dione (HPD), and N-hydroxythienopyrimidine-2,4-dione (HTPD). Analogues of these chemotypes generally exhibited improved potency and selectivity inhibiting RT RNase H over the best previous compounds and further validated the pharmacophore model. Extended structure-activity relationship (SAR) on the HPD inhibitor type by mainly altering the linkage generated a few subtypes showing exceptional potency (single-digit nanomolar) and excellent selectivity over the inhibition of RT pol and INST. In parallel, a structure-based approach also allowed us to design a unique double-winged HPD subtype to potently and selectively inhibit RT RNase H and effectively compete against the RNA/DNA substrate. Significantly, all potent HPD subtypes consistently inhibited HIV-1 in the cell culture, suggesting that carefully designed active site RNase H inhibitors with ultrapotency could partially overcome the barrier to antiviral phenotype. Overall, in addition to identifying our own inhibitor types, our medicinal chemistry efforts demonstrated the value of pharmacophore and structure-based approaches in designing active side-directed RNase H inhibitors and could provide a viable path to validating RNase H as a novel antiviral target.
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Affiliation(s)
- Lei Wang
- State Key Laboratory of Fine Chemicals, Department of Pharmacy, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Stefan G. Sarafianos
- Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - Zhengqiang Wang
- Center for Drug Design, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United States
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22
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Massari S, Corona A, Distinto S, Desantis J, Caredda A, Sabatini S, Manfroni G, Felicetti T, Cecchetti V, Pannecouque C, Maccioni E, Tramontano E, Tabarrini O. From cycloheptathiophene-3-carboxamide to oxazinone-based derivatives as allosteric HIV-1 ribonuclease H inhibitors. J Enzyme Inhib Med Chem 2019; 34:55-74. [PMID: 30362381 PMCID: PMC6211256 DOI: 10.1080/14756366.2018.1523901] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 09/11/2018] [Accepted: 09/11/2018] [Indexed: 11/30/2022] Open
Abstract
The paper focussed on a step-by-step structural modification of a cycloheptathiophene-3-carboxamide derivative recently identified by us as reverse transcriptase (RT)-associated ribonuclease H (RNase H) inhibitor. In particular, its conversion to a 2-aryl-cycloheptathienoozaxinone derivative and the successive thorough exploration of both 2-aromatic and cycloheptathieno moieties led to identify oxazinone-based compounds as new anti-RNase H chemotypes. The presence of the catechol moiety at the C-2 position of the scaffold emerged as critical to achieve potent anti-RNase H activity, which also encompassed anti-RNA dependent DNA polymerase (RDDP) activity for the tricyclic derivatives. Benzothienooxazinone derivative 22 resulted the most potent dual inhibitor exhibiting IC50s of 0.53 and 2.90 μM against the RNase H and RDDP functions. Mutagenesis and docking studies suggested that compound 22 binds two allosteric pockets within the RT, one located between the RNase H active site and the primer grip region and the other close to the DNA polymerase catalytic centre.
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Affiliation(s)
- Serena Massari
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Angela Corona
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, Cagliari, Italy
| | - Simona Distinto
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, Cagliari, Italy
| | - Jenny Desantis
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia, Italy
| | - Alessia Caredda
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, Cagliari, Italy
| | - Stefano Sabatini
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Giuseppe Manfroni
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Tommaso Felicetti
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Violetta Cecchetti
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Christophe Pannecouque
- Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, K.U. Leuven, K.U. Leuven, Leuven, Belgium
| | - Elias Maccioni
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, Cagliari, Italy
| | - Enzo Tramontano
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, Cagliari, Italy
- Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche (CNR), Monserrato, Italy
| | - Oriana Tabarrini
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
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23
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Wang Y, Wang X, Xiong Y, Kaushik AC, Muhammad J, Khan A, Dai H, Wei DQ. New strategy for identifying potential natural HIV-1 non-nucleoside reverse transcriptase inhibitors against drug-resistance: an in silico study. J Biomol Struct Dyn 2019; 38:3327-3341. [PMID: 31422767 DOI: 10.1080/07391102.2019.1656673] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Non-nucleosides reverse transcriptase inhibitors (NNRTIs), specifically targeting the HIV-1 reverse transcriptase (RT), play a unique role in anti-AIDS agents due to their high antiviral potency, structural diversity, and low toxicity in antiretroviral combination therapies used to treat HIV. However, due to the emergence of new drug-resistant strains, the development of novel NNRTIs with adequate potency, improved resistance profiles and less toxicity is highly required. In this work, a novel virtual screening strategy combined with structure-based drug design was proposed to discover the potential inhibitors against drug-resistant HIV strains. Seven structure-variant RTs, ranging from the wild type to a hypothetical multi-mutant were regarded as target proteins to perform structure-based virtual screening. Totally 23 small molecules with good binding affinity were identified from the Traditional Chinese Medicine database (TCM) as potential NNRTIs candidates. Among these hits, (+)-Hinokinin has confirmed anti-HIV activity, and some hits are structurally identical with anti-HIV compounds. Almost all these hits are consistent with external experimental results. Molecular simulations analysis revealed that top 2 hits (Pallidisetin A and Pallidisetin B) bind stably and in high affinity to HIV-RT, which are ready to be experimental confirmed. These results suggested that the strategy we proposed is feasible, trustworthy and effective. Our finding might be helpful in the identification of novel NNRTIs against drug-resistant, and also provide a new clue for the discovery of HIV drugs in natural products.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Yanjing Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, and Joint Laboratory of International Cooperation in Metabolic and Developmental Sciences, Ministry of Education, Shanghai Jiao Tong University, Shanghai, China.,Peng Cheng Laboratory, Nanshan District, Shenzhen, Guangdong, China
| | - Xiangeng Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, and Joint Laboratory of International Cooperation in Metabolic and Developmental Sciences, Ministry of Education, Shanghai Jiao Tong University, Shanghai, China.,Peng Cheng Laboratory, Nanshan District, Shenzhen, Guangdong, China
| | - Yi Xiong
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, and Joint Laboratory of International Cooperation in Metabolic and Developmental Sciences, Ministry of Education, Shanghai Jiao Tong University, Shanghai, China
| | - Aman Chandra Kaushik
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, and Joint Laboratory of International Cooperation in Metabolic and Developmental Sciences, Ministry of Education, Shanghai Jiao Tong University, Shanghai, China
| | - Junaid Muhammad
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, and Joint Laboratory of International Cooperation in Metabolic and Developmental Sciences, Ministry of Education, Shanghai Jiao Tong University, Shanghai, China
| | - Abbas Khan
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, and Joint Laboratory of International Cooperation in Metabolic and Developmental Sciences, Ministry of Education, Shanghai Jiao Tong University, Shanghai, China
| | - Hao Dai
- Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Dong-Qing Wei
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, and Joint Laboratory of International Cooperation in Metabolic and Developmental Sciences, Ministry of Education, Shanghai Jiao Tong University, Shanghai, China
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24
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Bertoletti N, Chan AH, Schinazi RF, Yin YW, Anderson KS. Structural insights into the recognition of nucleoside reverse transcriptase inhibitors by HIV-1 reverse transcriptase: First crystal structures with reverse transcriptase and the active triphosphate forms of lamivudine and emtricitabine. Protein Sci 2019; 28:1664-1675. [PMID: 31301259 PMCID: PMC6699100 DOI: 10.1002/pro.3681] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/03/2019] [Accepted: 07/08/2019] [Indexed: 12/27/2022]
Abstract
The retrovirus HIV-1 has been a major health issue since its discovery in the early 80s. In 2017, over 37 million people were infected with HIV-1, of which 1.8 million were new infections that year. Currently, the most successful treatment regimen is the highly active antiretroviral therapy (HAART), which consists of a combination of three to four of the current 26 FDA-approved HIV-1 drugs. Half of these drugs target the reverse transcriptase (RT) enzyme that is essential for viral replication. One class of RT inhibitors is nucleoside reverse transcriptase inhibitors (NRTIs), a crucial component of the HAART. Once incorporated into DNA, NRTIs function as a chain terminator to stop viral DNA replication. Unfortunately, treatment with NRTIs is sometimes linked to toxicity caused by off-target side effects. NRTIs may also target the replicative human mitochondrial DNA polymerase (Pol γ), causing long-term severe drug toxicity. The goal of this work is to understand the discrimination mechanism of different NRTI analogues by RT. Crystal structures and kinetic experiments are essential for the rational design of new molecules that are able to bind selectively to RT and not Pol γ. Structural comparison of NRTI-binding modes with both RT and Pol γ enzymes highlights key amino acids that are responsible for the difference in affinity of these drugs to their targets. Therefore, the long-term goal of this research is to develop safer, next generation therapeutics that can overcome off-target toxicity.
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Affiliation(s)
- Nicole Bertoletti
- Department of PharmacologyYale University School of MedicineNew HavenConnecticut
| | - Albert H. Chan
- Department of PharmacologyYale University School of MedicineNew HavenConnecticut
| | - Raymond F. Schinazi
- Laboratory of Biochemical Pharmacology, Department of Pediatrics, Center for AIDS ResearchEmory University School of MedicineAtlantaGeorgia
| | - Y. Whitney Yin
- Department of Pharmacology and ToxicologyUniversity of Texas Medical BranchGalvestonTexas
- Sealy Center for Structural BiologyUniversity of Texas Medical BranchGalvestonTexas
| | - Karen S. Anderson
- Department of PharmacologyYale University School of MedicineNew HavenConnecticut
- Department of Molecular Biophysics and BiochemistryYale University School of MedicineNew HavenConnecticut
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25
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Hyjek M, Figiel M, Nowotny M. RNases H: Structure and mechanism. DNA Repair (Amst) 2019; 84:102672. [PMID: 31371183 DOI: 10.1016/j.dnarep.2019.102672] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 07/05/2019] [Accepted: 07/12/2019] [Indexed: 12/11/2022]
Abstract
RNases H are a family of endonucleases that hydrolyze RNA residues in various nucleic acids. These enzymes are present in all branches of life, and their counterpart domains are also found in reverse transcriptases (RTs) from retroviruses and retroelements. RNases H are divided into two main classes (RNases H1 and H2 or type 1 and type 2 enzymes) with common structural features of the catalytic domain but different range of substrates for enzymatic cleavage. Additionally, a third class is found in some Archaea and bacteria. Besides distinct cellular functions specific for each type of RNases H, this family of proteins is generally involved in the maintenance of genome stability with overlapping and cooperative role in removal of R-loops thus preventing their accumulation. Extensive biochemical and structural studies of RNases H provided not only a comprehensive and complete picture of their mechanism but also revealed key basic principles of nucleic acid recognition and processing. RNase H1 is present in prokaryotes and eukaryotes and cleaves RNA in RNA/DNA hybrids. Its main function is hybrid removal, notably in the context of R-loops. RNase H2, which is also present in all branches of life, can play a similar role but it also has a specialized function in the cleavage of single ribonucleotides embedded in the DNA. RNase H3 is present in Archaea and bacteria and is closely related to RNase H2 in sequence and structure but has RNase H1-like biochemical properties. This review summarizes the mechanisms of substrate recognition and enzymatic cleavage by different classes of RNases H with particular insights into structural features of nucleic acid binding, specificity towards RNA and/or DNA strands and catalysis.
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Affiliation(s)
- Malwina Hyjek
- ProBiostructures, International Institute of Molecular and Cell Biology, Trojdena 4, Warsaw, 02-109, Poland.
| | - Małgorzata Figiel
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Trojdena 4, Warsaw, 02-109, Poland.
| | - Marcin Nowotny
- ProBiostructures, International Institute of Molecular and Cell Biology, Trojdena 4, Warsaw, 02-109, Poland; Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Trojdena 4, Warsaw, 02-109, Poland.
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26
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Larsen KP, Choi J, Prabhakar A, Puglisi EV, Puglisi JD. Relating Structure and Dynamics in RNA Biology. Cold Spring Harb Perspect Biol 2019; 11:11/7/a032474. [PMID: 31262948 DOI: 10.1101/cshperspect.a032474] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Recent advances in structural biology methods have enabled a surge in the number of RNA and RNA-protein assembly structures available at atomic or near-atomic resolution. These complexes are often trapped in discrete conformational states that exist along a mechanistic pathway. Single-molecule fluorescence methods provide temporal resolution to elucidate the dynamic mechanisms of processes involving complex RNA and RNA-protein assemblies, but interpretation of such data often requires previous structural knowledge. Here we highlight how single-molecule tools can directly complement structural approaches for two processes--translation and reverse transcription-to provide a dynamic view of molecular function.
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Affiliation(s)
- Kevin P Larsen
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305.,Biophysics Program, Stanford University, Stanford, California 94305
| | - Junhong Choi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305.,Department of Applied Physics, Stanford University, Stanford, California 94305
| | - Arjun Prabhakar
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305.,Biophysics Program, Stanford University, Stanford, California 94305
| | - Elisabetta Viani Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305
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27
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DeStefano JJ. Non-nucleoside Reverse Transcriptase Inhibitors Inhibit Reverse Transcriptase through a Mutually Exclusive Interaction with Divalent Cation-dNTP Complexes. Biochemistry 2019; 58:2176-2187. [PMID: 30900874 DOI: 10.1021/acs.biochem.9b00028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are considered noncompetitive inhibitors that structurally alter reverse transcriptase (RT) and dramatically decrease catalysis. In this report, biochemical analysis with various divalent cations was used to demonstrate that NNRTIs and divalent cation-dNTP complexes are mutually exclusive, inhibiting each other's binding to RT/primer/template (RT-P/T) complexes. The binding of catalytically competent divalent cation-dNTP complexes to RT-P/T was measured with Mg2+, Mn2+, Zn2+, Co2+, and Ni2+ using Ca2+, a noncatalytic cation, for displacement. Binding strength order was Mn2+ ≈ Zn2+ ≫ Co2+ > Mg2+ ≈ Ni2+. Consistent with but not exclusive to mutually exclusive binding, primer extension assays showed that stronger divalent cation-dNTP complexes were more resistant to NNRTIs (efavirenz (EFV), rilpivirine (RPV), and nevirapine (NVP)). Filtration assays demonstrated that divalent cation-dNTP complexes inhibited the binding of 14C-labeled EFV to RT-P/T with stronger binding complexes formed with Mn2+ inhibiting more potently than those with Mg2+. Conversely, filter binding assays demonstrated that EFV inhibited 3H-labeled dNTP binding to RT-P/T complexes with displacement of Mn2+-dNTP complexes requiring much greater concentrations of EFV than the more weakly bound Mg2+-dNTP complexes. EFV bound relatively weakly to the NNRTI resistant K103N RT; but, binding was modestly enhanced in the presence of P/T, and EFV was easily displaced by divalent cation-dNTP complexes. This suggests that K103N overcomes EFV inhibition mostly by binding more weakly to the drug and is in contrast to other reports that indicate K103N has little to no effect on drug or dNTP binding. Overall, this biochemical analysis supports recent biophysical analyses of NNRTI-RT interactions that indicate mutually exclusive binding.
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Affiliation(s)
- Jeffrey J DeStefano
- Department of Cell Biology and Molecular Genetics and the Maryland Pathogen Research Institute , University of Maryland , College Park , Maryland 20742 , United States
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28
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Abstract
RT is a key enzyme in the life cycle of HIV, and is targeted by multiple antiviral drugs. Although for most of its function RT binds a dsDNA or RNA–DNA template–primer substrate, initiation of reverse transcription involves binding of dsRNA. The current study presents a structure of an RT/dsRNA complex that has the basic components of a reverse transcription initiation complex (RTIC). The unique structural features help understand the significantly slower rate of nucleotide incorporation by an RTIC compared with a catalytically efficient reverse transcription elongation complex. This complex may help in designing new experiments for understanding the intricate and slow process of reverse transcription initiation. The initiation phase of HIV reverse transcription has features that are distinct from its elongation phase. The first structure of a reverse transcription initiation complex (RTIC) that trapped the complex after incorporation of one ddCMP nucleotide was published recently [Larsen KP, et al. (2018) Nature 557:118–122]. Here we report a crystal structure of a catalytically active HIV-1 RT/dsRNA complex that mimics the state of the RTIC before the first nucleotide incorporation. The structure reveals that the dsRNA-bound conformation of RT is closer to that of RT bound to a nonnucleoside RT inhibitor (NNRTI) and dsDNA; a hyperextended thumb conformation helps to accommodate the relatively wide dsRNA duplex. The RNA primer 3′ end is positioned 5 Å away from the polymerase site; however, unlike in an NNRTI-bound state in which structural elements of RT restrict the movement of the primer, the primer terminus of dsRNA is not blocked from reaching the active site of RT. The observed structural changes and energetic cost of bringing the primer 3′ end to the priming site are hypothesized to explain the slower nucleotide incorporation rate of the RTIC. An unusual crystal lattice interaction of dsRNA with its symmetry mate is reminiscent of the RNA architecture within the extended vRNA–tRNALys3 in the RTIC. This RT/dsRNA complex captures the key structural characteristics and components of the RTIC, including the RT conformational changes and interactions with the dsRNA primer-binding site region, and these features have implications for better understanding of RT initiation.
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29
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Yang F, Zheng G, Fu T, Li X, Tu G, Li YH, Yao X, Xue W, Zhu F. Prediction of the binding mode and resistance profile for a dual-target pyrrolyl diketo acid scaffold against HIV-1 integrase and reverse-transcriptase-associated ribonuclease H. Phys Chem Chem Phys 2019; 20:23873-23884. [PMID: 29947629 DOI: 10.1039/c8cp01843j] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The rapid emergence of drug-resistant variants is one of the most common causes of highly active antiretroviral therapeutic (HAART) failure in patients infected with HIV-1. Compared with the existing HAART, the recently developed pyrrolyl diketo acid scaffold targeting both HIV-1 integrase (IN) and reverse transcriptase-associated ribonuclease H (RNase H) is an efficient approach to counteract the failure of anti-HIV treatment due to drug resistance. However, the binding mode and potential resistance profile of these inhibitors with important mechanistic principles remain poorly understood. To address this issue, an integrated computational method was employed to investigate the binding mode of inhibitor JMC6F with HIV-1 IN and RNase H. By using per-residue binding free energy decomposition analysis, the following residues: Asp64, Thr66, Leu68, Asp116, Tyr143, Gln148 and Glu152 in IN, Asp443, Glu478, Trp536, Lys541 and Asp549 in RNase H were identified as key residues for JMC6F binding. And then computational alanine scanning was carried to further verify the key residues. Moreover, the resistance profile of the currently known major mutations in HIV-1 IN and 2 mutations in RNase H against JMC6F was predicted by in silico mutagenesis studies. The results demonstrated that only three mutations in HIV-1 IN (Y143C, Q148R and N155H) and two mutations in HIV-1 RNase H (Y501R and Y501W) resulted in a reduction of JMC6F potency, thus indicating their potential role in providing resistance to JMC6F. These data provided important insights into the binding mode and resistance profile of the inhibitors with a pyrrolyl diketo acid scaffold in HIV-1 IN and RNase H, which would be helpful for the development of more effective dual HIV-1 IN and RNase H inhibitors.
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Affiliation(s)
- Fengyuan Yang
- Innovative Drug Research and Bioinformatics Group, School of Pharmaceutical Sciences and Collaborative Innovation Center for Brain Science, Chongqing University, Chongqing 401331, China.
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30
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Döring J, Hurek T. Dual coding potential of a 2',5'-branched ribonucleotide in DNA. RNA (NEW YORK, N.Y.) 2019; 25:105-120. [PMID: 30361268 PMCID: PMC6298571 DOI: 10.1261/rna.068486.118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 10/15/2018] [Indexed: 06/08/2023]
Abstract
Branchpoints in RNA templates are highly mutagenic, but it is not known yet whether this also applies to branchpoints in DNA templates. Here, we report how nucleic acid polymerases replicate a 2',5'-branched DNA (bDNA) molecule. We constructed long-chained bDNA templates containing a branch guanosine and T7 promoters at both arms by splinted ligation. Quantitative real-time PCR analysis was used to investigate whether a branchpoint blocks DNA synthesis from the two arms in the same manner. We find that the blocking effect of a branchpoint is arm-specific. DNA synthesis from the 2'-arm is more than 20,000-fold decreased, whereas from the 3'-arm only 15-fold. Our sequence analysis of full-length nucleic acid generated by Taq DNA polymerase, Moloney murine leukemia virus reverse transcriptase, and T7 RNA polymerase from the 2'-arm of bDNA shows that the branched guanine has a dual coding potential and can base-pair with cytosine and guanine. We find that branchpoint templating is influenced by the type of the surrounding nucleic acid and is probably modulated by polymerase and RNase H active sites. We show that the branchpoint bypass by the polymerases from the 3'-arm of bDNA is predominantly error-free, indicating that bDNA is not as highly mutagenic as 2',5'-branched RNA.
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Affiliation(s)
- Jessica Döring
- Department of Microbe-Plant Interactions, CBIB (Center for Biomolecular Interactions Bremen), University of Bremen, D-28334 Bremen, Germany
| | - Thomas Hurek
- Department of Microbe-Plant Interactions, CBIB (Center for Biomolecular Interactions Bremen), University of Bremen, D-28334 Bremen, Germany
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31
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Martinez SE, Bauman JD, Das K, Arnold E. Structure of HIV-1 reverse transcriptase/d4TTP complex: Novel DNA cross-linking site and pH-dependent conformational changes. Protein Sci 2018; 28:587-597. [PMID: 30499174 DOI: 10.1002/pro.3559] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 11/16/2018] [Accepted: 11/19/2018] [Indexed: 12/22/2022]
Abstract
Stavudine (d4T, 2',3'-didehydro-2',3'-dideoxythymidine) was one of the first chain-terminating nucleoside analogs used to treat HIV infection. We present the first structure of the active, triphosphate form of d4T (d4TTP) bound to a catalytic complex of HIV-1 RT/dsDNA template-primer. We also present a new strategy for disulfide (S-S) chemical cross-linking between N6 of a modified adenine at the second overhang base to I63C in the fingers subdomain of RT. The cross-link site is upstream of the duplex-binding region of RT, however, the structure is very similar to published RT structures with cross-linking to Q258C in the thumb, which suggests that cross-linking at either site does not appreciably perturb the RT/DNA structures. RT has a catalytic maximum at pH 7.5. We determined the X-ray structures of the I63C-RT/dsDNA/d4TTP cross-linked complexes at pH 7, 7.5, 8, 8.5, 9, and 9.5. We found small (~0.5 Å), pH-dependent motions of the fingers subdomain that folds in to form the dNTP-binding pocket. We propose that the pH-activity profile of RT relates to this motion of the fingers. Due to side effects of neuropathy and lipodystrophy, use of d4T has been stopped in most countries, however, chemical modification of d4T might lead to the development of a new class of nucleoside analogs targeting RNA and DNA polymerases.
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Affiliation(s)
- Sergio E Martinez
- Center for Advanced Biotechnology and Medicine, and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854.,Rega Institute for Medical Research and Department of Microbiology and Immunology, KU Leuven, Leuven, 3000, Belgium
| | - Joseph D Bauman
- Center for Advanced Biotechnology and Medicine, and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854
| | - Kalyan Das
- Rega Institute for Medical Research and Department of Microbiology and Immunology, KU Leuven, Leuven, 3000, Belgium
| | - Eddy Arnold
- Center for Advanced Biotechnology and Medicine, and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854
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32
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Lai CT, Schatz GC. Free-Energy Profiles for A-/B-DNA Conformational Transitions in Isolated and Aggregated States from All-Atom Molecular Dynamics Simulation. J Phys Chem B 2018; 122:7990-7996. [PMID: 30067905 DOI: 10.1021/acs.jpcb.8b04573] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In ordinary aqueous solution, B-DNA is the major structural form of DNA. After the addition of ethanol, DNA is thought to be aggregated/condensed in the A-form structure. However, there is uncertainty as to whether the B-to-A conformational change is connected to the aggregation/condensation steps. In this study, we performed all-atom molecular dynamics simulations and calculated the free-energy surface involved in the A/B conformational transition for isolated and aggregated Dickerson-Drew dodecamers (DDDs) in water and 85% ethanol environments. We found in the case of an isolated DDD, the overall free-energy profile is entirely downhill to give the B-DNA conformation in both water and 85% ethanol. However, in the aggregated state and 85% ethanol environment, there is a free-energy minimum associated with the A-DNA region in addition to the global B-DNA minimum, and there is a ∼3 kcal/mol free-energy barrier to the A-to-B conformational change. The molecular dynamics results suggest that aggregation of DNA is essential for forming A-DNA.
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Affiliation(s)
- Cheng-Tsung Lai
- Department of Chemistry , Northwestern University , Evanston , Illinois 60208-3113 , United States
| | - George C Schatz
- Department of Chemistry , Northwestern University , Evanston , Illinois 60208-3113 , United States
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33
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Tarasova O, Poroikov V, Veselovsky A. Molecular Docking Studies of HIV-1 Resistance to Reverse Transcriptase Inhibitors: Mini-Review. Molecules 2018; 23:molecules23051233. [PMID: 29883406 PMCID: PMC6100360 DOI: 10.3390/molecules23051233] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 05/15/2018] [Accepted: 05/15/2018] [Indexed: 02/05/2023] Open
Abstract
Currently, millions of people are living with human immunodeficiency virus type 1 (HIV-1), which causes acquired immunodeficiency syndrome. However, the spread of the HIV-1 resistance to antiviral agents is the major problem in the antiretroviral therapy and medical management of HIV-infected patients. HIV-1 reverse transcriptase (RT) is one of the key viral targets for HIV-1 inhibition. Therefore, the studies on the combatting the HIV resistance that occurs due to the structural changes in RT, are in great demand. This work aims to provide an overview of the state-of-the-art molecular docking approaches applied to the studies of the HIV-1 resistance, associated with RT structure changes. We have reviewed recent studies using molecular docking with mutant forms of RT. The work discusses the modifications of molecular docking, which have been developed to find the novel molecules active against resistance mutants of RT and/or recombinant strains of HIV-1. The perspectives of the existing algorithms of molecular docking to the studies on molecular mechanisms of resistance and selection of the correct binding poses for the reverse transcriptase inhibitors are discussed.
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Affiliation(s)
- Olga Tarasova
- Institute of Biomedical Chemistry, 10 Building 8, Pogodinskaya st., Moscow 119121, Russia.
| | - Vladimir Poroikov
- Institute of Biomedical Chemistry, 10 Building 8, Pogodinskaya st., Moscow 119121, Russia.
| | - Alexander Veselovsky
- Institute of Biomedical Chemistry, 10 Building 8, Pogodinskaya st., Moscow 119121, Russia.
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34
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Šponer J, Bussi G, Krepl M, Banáš P, Bottaro S, Cunha RA, Gil-Ley A, Pinamonti G, Poblete S, Jurečka P, Walter NG, Otyepka M. RNA Structural Dynamics As Captured by Molecular Simulations: A Comprehensive Overview. Chem Rev 2018; 118:4177-4338. [PMID: 29297679 PMCID: PMC5920944 DOI: 10.1021/acs.chemrev.7b00427] [Citation(s) in RCA: 336] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Indexed: 12/14/2022]
Abstract
With both catalytic and genetic functions, ribonucleic acid (RNA) is perhaps the most pluripotent chemical species in molecular biology, and its functions are intimately linked to its structure and dynamics. Computer simulations, and in particular atomistic molecular dynamics (MD), allow structural dynamics of biomolecular systems to be investigated with unprecedented temporal and spatial resolution. We here provide a comprehensive overview of the fast-developing field of MD simulations of RNA molecules. We begin with an in-depth, evaluatory coverage of the most fundamental methodological challenges that set the basis for the future development of the field, in particular, the current developments and inherent physical limitations of the atomistic force fields and the recent advances in a broad spectrum of enhanced sampling methods. We also survey the closely related field of coarse-grained modeling of RNA systems. After dealing with the methodological aspects, we provide an exhaustive overview of the available RNA simulation literature, ranging from studies of the smallest RNA oligonucleotides to investigations of the entire ribosome. Our review encompasses tetranucleotides, tetraloops, a number of small RNA motifs, A-helix RNA, kissing-loop complexes, the TAR RNA element, the decoding center and other important regions of the ribosome, as well as assorted others systems. Extended sections are devoted to RNA-ion interactions, ribozymes, riboswitches, and protein/RNA complexes. Our overview is written for as broad of an audience as possible, aiming to provide a much-needed interdisciplinary bridge between computation and experiment, together with a perspective on the future of the field.
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Affiliation(s)
- Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences , Kralovopolska 135 , Brno 612 65 , Czech Republic
| | - Giovanni Bussi
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Miroslav Krepl
- Institute of Biophysics of the Czech Academy of Sciences , Kralovopolska 135 , Brno 612 65 , Czech Republic
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
| | - Pavel Banáš
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
| | - Sandro Bottaro
- Structural Biology and NMR Laboratory, Department of Biology , University of Copenhagen , Copenhagen 2200 , Denmark
| | - Richard A Cunha
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Alejandro Gil-Ley
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Giovanni Pinamonti
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Simón Poblete
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Petr Jurečka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
| | - Nils G Walter
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
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35
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Sebastián-Martín A, Barrioluengo V, Menéndez-Arias L. Transcriptional inaccuracy threshold attenuates differences in RNA-dependent DNA synthesis fidelity between retroviral reverse transcriptases. Sci Rep 2018; 8:627. [PMID: 29330371 PMCID: PMC5766491 DOI: 10.1038/s41598-017-18974-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 12/18/2017] [Indexed: 01/01/2023] Open
Abstract
In M13mp2 lacZα forward mutation assays measuring intrinsic fidelity of DNA-dependent DNA synthesis, wild-type human immunodeficiency virus type 1 (HIV-1) RTs of group M/subtype B previously showed >10-fold higher error rates than murine leukaemia virus (MLV) and avian myeloblastosis virus (AMV) RTs. An adapted version of the assay was used to obtain error rates of RNA-dependent DNA synthesis for several RTs, including wild-type HIV-1BH10, HIV-1ESP49, AMV and MLV RTs, and the high-fidelity mutants of HIV-1ESP49 RT K65R and K65R/V75I. Our results showed that there were less than two-fold differences in fidelity between the studied RTs with error rates ranging within 2.5 × 10-5 and 3.5 × 10-5. These results were consistent with the existence of a transcriptional inaccuracy threshold, generated by the RNA polymerase while synthesizing the RNA template used in the assay. A modest but consistent reduction of the inaccuracy threshold was achieved by lowering the pH and Mg2+ concentration of the transcription reaction. Despite assay limitations, we conclude that HIV-1BH10 and HIV-1ESP49 RTs are less accurate when copying DNA templates than RNA templates. Analysis of the RNA-dependent mutational spectra revealed a higher tendency to introduce large deletions at the initiation of reverse transcription by all HIV-1 RTs except the double-mutant K65R/V75I.
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Affiliation(s)
- Alba Sebastián-Martín
- Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas & Universidad Autónoma de Madrid), c/Nicolás Cabrera, 1, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Verónica Barrioluengo
- Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas & Universidad Autónoma de Madrid), c/Nicolás Cabrera, 1, Campus de Cantoblanco, 28049, Madrid, Spain.,DiaSorin Iberia S.A., Avenida de la Vega 1, 28108, Alcobendas (Madrid), Spain
| | - Luis Menéndez-Arias
- Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas & Universidad Autónoma de Madrid), c/Nicolás Cabrera, 1, Campus de Cantoblanco, 28049, Madrid, Spain.
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36
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Structure of HIV-1 reverse transcriptase cleaving RNA in an RNA/DNA hybrid. Proc Natl Acad Sci U S A 2018; 115:507-512. [PMID: 29295939 DOI: 10.1073/pnas.1719746115] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
HIV-1 reverse transcriptase (RT) contains both DNA polymerase and RNase H activities to convert the viral genomic RNA to dsDNA in infected host cells. Here we report the 2.65-Å resolution structure of HIV-1 RT engaging in cleaving RNA in an RNA/DNA hybrid. A preferred substrate sequence is absolutely required to enable the RNA/DNA hybrid to adopt the distorted conformation needed to interact properly with the RNase H active site in RT. Substituting two nucleotides 4 bp upstream from the cleavage site results in scissile-phosphate displacement by 4 Å. We also have determined the structure of HIV-1 RT complexed with an RNase H-resistant polypurine tract sequence, which adopts a rigid structure and is accommodated outside of the nuclease active site. Based on this newly gained structural information and a virtual drug screen, we have identified an inhibitor specific for the viral RNase H but not for its cellular homologs.
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37
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Stamos JL, Lentzsch AM, Lambowitz AM. Structure of a Thermostable Group II Intron Reverse Transcriptase with Template-Primer and Its Functional and Evolutionary Implications. Mol Cell 2017; 68:926-939.e4. [PMID: 29153391 DOI: 10.1016/j.molcel.2017.10.024] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 09/29/2017] [Accepted: 10/19/2017] [Indexed: 12/14/2022]
Abstract
Bacterial group II intron reverse transcriptases (RTs) function in both intron mobility and RNA splicing and are evolutionary predecessors of retrotransposon, telomerase, and retroviral RTs as well as the spliceosomal protein Prp8 in eukaryotes. Here we determined a crystal structure of a full-length thermostable group II intron RT in complex with an RNA template-DNA primer duplex and incoming deoxynucleotide triphosphate (dNTP) at 3.0-Å resolution. We find that the binding of template-primer and key aspects of the RT active site are surprisingly different from retroviral RTs but remarkably similar to viral RNA-dependent RNA polymerases. The structure reveals a host of features not seen previously in RTs that may contribute to distinctive biochemical properties of group II intron RTs, and it provides a prototype for many related bacterial and eukaryotic non-LTR retroelement RTs. It also reveals how protein structural features used for reverse transcription evolved to promote the splicing of both group II and spliceosomal introns.
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Affiliation(s)
- Jennifer L Stamos
- Institute for Cellular and Molecular Biology and Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Alfred M Lentzsch
- Institute for Cellular and Molecular Biology and Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Alan M Lambowitz
- Institute for Cellular and Molecular Biology and Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA.
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38
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Figiel M, Krepl M, Park S, Poznański J, Skowronek K, Gołąb A, Ha T, Šponer J, Nowotny M. Mechanism of polypurine tract primer generation by HIV-1 reverse transcriptase. J Biol Chem 2017; 293:191-202. [PMID: 29122886 PMCID: PMC5766924 DOI: 10.1074/jbc.m117.798256] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 11/02/2017] [Indexed: 12/27/2022] Open
Abstract
HIV-1 reverse transcriptase (RT) possesses both DNA polymerase activity and RNase H activity that act in concert to convert single-stranded RNA of the viral genome to double-stranded DNA that is then integrated into the DNA of the infected cell. Reverse transcriptase-catalyzed reverse transcription critically relies on the proper generation of a polypurine tract (PPT) primer. However, the mechanism of PPT primer generation and the features of the PPT sequence that are critical for its recognition by HIV-1 RT remain unclear. Here, we used a chemical cross-linking method together with molecular dynamics simulations and single-molecule assays to study the mechanism of PPT primer generation. We found that the PPT was specifically and properly recognized within covalently tethered HIV-1 RT-nucleic acid complexes. These findings indicated that recognition of the PPT occurs within a stable catalytic complex after its formation. We found that this unique recognition is based on two complementary elements that rely on the PPT sequence: RNase H sequence preference and incompatibility of the poly(rA/dT) tract of the PPT with the nucleic acid conformation that is required for RNase H cleavage. The latter results from rigidity of the poly(rA/dT) tract and leads to base-pair slippage of this sequence upon deformation into a catalytically relevant geometry. In summary, our results reveal an unexpected mechanism of PPT primer generation based on specific dynamic properties of the poly(rA/dT) segment and help advance our understanding of the mechanisms in viral RNA reverse transcription.
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Affiliation(s)
- Małgorzata Figiel
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland
| | - Miroslav Krepl
- Institute of Biophysics of the Czech Academy of Sciences, 612 65 Brno, Czech Republic; Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University Olomouc, 771 46 Olomouc, Czech Republic
| | - Sangwoo Park
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University, Baltimore, Maryland 21205
| | - Jarosław Poznański
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Krzysztof Skowronek
- Biophysics Core Facility, International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland
| | - Agnieszka Gołąb
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University, Baltimore, Maryland 21205; Howard Hughes Medical Institute, Baltimore, Maryland 21205; Department of Biophysics, The Johns Hopkins University, Baltimore, Maryland 21205; Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, Maryland 21205
| | - Jiří Šponer
- Biophysics Core Facility, International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland; Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University Olomouc, 771 46 Olomouc, Czech Republic
| | - Marcin Nowotny
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland.
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39
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Figiel M, Krepl M, Poznanski J, Golab A, Šponer J, Nowotny M. Coordination between the polymerase and RNase H activity of HIV-1 reverse transcriptase. Nucleic Acids Res 2017; 45:3341-3352. [PMID: 28108662 PMCID: PMC5389522 DOI: 10.1093/nar/gkx004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 01/03/2017] [Indexed: 11/17/2022] Open
Abstract
Replication of human immunodeficiency virus 1 (HIV-1) involves conversion of its single-stranded RNA genome to double-stranded DNA, which is integrated into the genome of the host. This conversion is catalyzed by reverse transcriptase (RT), which possesses DNA polymerase and RNase H domains. The available crystal structures suggest that at any given time the RNA/DNA substrate interacts with only one active site of the two domains of HIV-1 RT. Unknown is whether a simultaneous interaction of the substrate with polymerase and RNase H active sites is possible. Therefore, the mechanism of the coordination of the two activities is not fully understood. We performed molecular dynamics simulations to obtain a conformation of the complex in which the unwound RNA/DNA substrate simultaneously interacts with the polymerase and RNase H active sites. When the RNA/DNA hybrid was immobilized at the polymerase active site, RNase H cleavage occurred, experimentally verifying that the substrate can simultaneously interact with both active sites. These findings demonstrate the existence of a transient conformation of the HIV-1 RT substrate complex, which is important for modulating and coordinating the enzymatic activities of HIV-1 RT.
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Affiliation(s)
- Malgorzata Figiel
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland
| | - Miroslav Krepl
- Institute of Biophysics, Academy of Sciences of the Czech Republic, 612 65 Brno, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University Olomouc, 77146 Olomouc, Czech Republic
| | - Jaroslaw Poznanski
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Agnieszka Golab
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland
| | - Jirí Šponer
- Institute of Biophysics, Academy of Sciences of the Czech Republic, 612 65 Brno, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University Olomouc, 77146 Olomouc, Czech Republic
| | - Marcin Nowotny
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland
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40
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Vernekar SKV, Tang J, Wu B, Huber AD, Casey MC, Myshakina N, Wilson DJ, Kankanala J, Kirby KA, Parniak MA, Sarafianos SG, Wang Z. Double-Winged 3-Hydroxypyrimidine-2,4-diones: Potent and Selective Inhibition against HIV-1 RNase H with Significant Antiviral Activity. J Med Chem 2017; 60:5045-5056. [PMID: 28525279 DOI: 10.1021/acs.jmedchem.7b00440] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Human immunodeficiency virus (HIV) reverse transcriptase (RT)-associated ribonuclease H (RNase H) remains the only virally encoded enzymatic function yet to be exploited as an antiviral target. One of the possible challenges may be that targeting HIV RNase H is confronted with a steep substrate barrier. We have previously reported a 3-hydroxypyrimidine-2,4-dione (HPD) subtype that potently and selectively inhibited RNase H without inhibiting HIV in cell culture. We report herein a critical redesign of the HPD chemotype featuring an additional wing at the C5 position that led to drastically improved RNase H inhibition and significant antiviral activity. Structure-activity relationship (SAR) concerning primarily the length and flexibility of the two wings revealed important structural features that dictate the potency and selectivity of RNase H inhibition as well as the observed antiviral activity. Our current medicinal chemistry data also revealed that the RNase H biochemical inhibition largely correlated the antiviral activity.
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Affiliation(s)
- Sanjeev Kumar V Vernekar
- Center for Drug Design, Academic Health Center, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Jing Tang
- Center for Drug Design, Academic Health Center, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Bulan Wu
- Center for Drug Design, Academic Health Center, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Andrew D Huber
- Department of Veterinary Pathobiology, Christopher S. Bond Life Sciences Center, University of Missouri , Columbia, Missouri 65211, United States
| | - Mary C Casey
- Department of Molecular Microbiology and Immunology, Christopher S. Bond Life Sciences Center, University of Missouri School of Medicine , Columbia, Missouri 65211, United States
| | - Nataliya Myshakina
- Department of Natural Science, Chatham University , 1 Woodland Road, Pittsburgh, Pennsylvania 15232, United States
| | - Daniel J Wilson
- Center for Drug Design, Academic Health Center, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Jayakanth Kankanala
- Center for Drug Design, Academic Health Center, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Karen A Kirby
- Department of Molecular Microbiology and Immunology, Christopher S. Bond Life Sciences Center, University of Missouri School of Medicine , Columbia, Missouri 65211, United States
| | - Michael A Parniak
- Department of Microbiology & Molecular Genetics, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15219, United States
| | - Stefan G Sarafianos
- Department of Molecular Microbiology and Immunology, Christopher S. Bond Life Sciences Center, University of Missouri School of Medicine , Columbia, Missouri 65211, United States.,Department of Biochemistry, University of Missouri , Columbia, Missouri 65211, United States
| | - Zhengqiang Wang
- Center for Drug Design, Academic Health Center, University of Minnesota , Minneapolis, Minnesota 55455, United States
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41
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Structural Insights into HIV Reverse Transcriptase Mutations Q151M and Q151M Complex That Confer Multinucleoside Drug Resistance. Antimicrob Agents Chemother 2017; 61:AAC.00224-17. [PMID: 28396546 DOI: 10.1128/aac.00224-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 03/28/2017] [Indexed: 12/26/2022] Open
Abstract
HIV-1 reverse transcriptase (RT) is targeted by multiple drugs. RT mutations that confer resistance to nucleoside RT inhibitors (NRTIs) emerge during clinical use. Q151M and four associated mutations, A62V, V75I, F77L, and F116Y, were detected in patients failing therapies with dideoxynucleosides (didanosine [ddI], zalcitabine [ddC]) and/or zidovudine (AZT). The cluster of the five mutations is referred to as the Q151M complex (Q151Mc), and an RT or virus containing Q151Mc exhibits resistance to multiple NRTIs. To understand the structural basis for Q151M and Q151Mc resistance, we systematically determined the crystal structures of the wild-type RT/double-stranded DNA (dsDNA)/dATP (complex I), wild-type RT/dsDNA/ddATP (complex II), Q151M RT/dsDNA/dATP (complex III), Q151Mc RT/dsDNA/dATP (complex IV), and Q151Mc RT/dsDNA/ddATP (complex V) ternary complexes. The structures revealed that the deoxyribose rings of dATP and ddATP have 3'-endo and 3'-exo conformations, respectively. The single mutation Q151M introduces conformational perturbation at the deoxynucleoside triphosphate (dNTP)-binding pocket, and the mutated pocket may exist in multiple conformations. The compensatory set of mutations in Q151Mc, particularly F116Y, restricts the side chain flexibility of M151 and helps restore the DNA polymerization efficiency of the enzyme. The altered dNTP-binding pocket in Q151Mc RT has the Q151-R72 hydrogen bond removed and has a switched conformation for the key conserved residue R72 compared to that in wild-type RT. On the basis of a modeled structure of hepatitis B virus (HBV) polymerase, the residues R72, Y116, M151, and M184 in Q151Mc HIV-1 RT are conserved in wild-type HBV polymerase as residues R41, Y89, M171, and M204, respectively; functionally, both Q151Mc HIV-1 and wild-type HBV are resistant to dideoxynucleoside analogs.
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42
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Wang Z, Zhang J, Li F, Ji X, Liao L, Ma L, Xing H, Feng Y, Li D, Shao Y. Drug resistance-related mutations T369V/I in the connection subdomain of HIV-1 reverse transcriptase severely impair viral fitness. Virus Res 2017; 233:8-16. [PMID: 28279801 DOI: 10.1016/j.virusres.2017.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 01/22/2017] [Accepted: 03/01/2017] [Indexed: 10/20/2022]
Abstract
Fitness is a key parameter in the measurement of transmission capacity of individual drug-resistant HIV. Drug-resistance related mutations (DRMs) T369V/I and A371V in the connection subdomain (CN) of reverse transcriptase (RT) occur at higher frequencies in the individuals experiencing antiretroviral therapy failure. Here, we evaluated the effects of T369V/I and A371V on viral fitness, in the presence or in the absence of thymidine analogue resistance-associated mutations (TAMs) and assessed the effect of potential RT structure-related mechanism on change in viral fitness. Mutations T369V/I, A371V, alone or in combination with TAMs were introduced into a modified HIV-1 infectious clone AT1 by site-directed mutagenesis. Then, experiments on mutant and wild-type virus AT2 were performed separately using a growth-competition assay, and then the relative fitness was calculated. Structural analysis of RT was conducted using Pymol software. Results showed that T369V/I severely impaired the relative virus fitness, and A371V compensated for the viral fitness reduction caused by TAMs. Structural modeling of RT suggests that T369V/I substitutions disrupt powerful hydrogen bonds formed by T369 and V365 in p51 and p66. This study indicates that the secondary DRMs within CN might efficiently damage viral fitness, and provides valuable information for clinical surveillance and prevention of HIV-1 strains carrying these DRMs.
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Affiliation(s)
- Zheng Wang
- State Key Laboratory of Infectious Diseases Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of infectious Diseases, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China; Division of Research of Virology and Immunology, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China.
| | - Junli Zhang
- State Key Laboratory of Infectious Diseases Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of infectious Diseases, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China; Division of Research of Virology and Immunology, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China
| | - Fan Li
- State Key Laboratory of Infectious Diseases Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of infectious Diseases, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China; Division of Research of Virology and Immunology, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China
| | - Xiaolin Ji
- State Key Laboratory of Infectious Diseases Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of infectious Diseases, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China; Division of Research of Virology and Immunology, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China
| | - Lingjie Liao
- State Key Laboratory of Infectious Diseases Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of infectious Diseases, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China; Division of Research of Virology and Immunology, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China
| | - Liying Ma
- State Key Laboratory of Infectious Diseases Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of infectious Diseases, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China; Division of Research of Virology and Immunology, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China
| | - Hui Xing
- State Key Laboratory of Infectious Diseases Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of infectious Diseases, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China; Division of Research of Virology and Immunology, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China
| | - Yi Feng
- State Key Laboratory of Infectious Diseases Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of infectious Diseases, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China; Division of Research of Virology and Immunology, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China
| | - Dan Li
- State Key Laboratory of Infectious Diseases Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of infectious Diseases, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China; Division of Research of Virology and Immunology, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China
| | - Yiming Shao
- State Key Laboratory of Infectious Diseases Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of infectious Diseases, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China; Division of Research of Virology and Immunology, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China.
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43
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Achuthan V, Singh K, DeStefano JJ. Physiological Mg 2+ Conditions Significantly Alter the Inhibition of HIV-1 and HIV-2 Reverse Transcriptases by Nucleoside and Non-Nucleoside Inhibitors in Vitro. Biochemistry 2016; 56:33-46. [PMID: 27936595 DOI: 10.1021/acs.biochem.6b00943] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Reverse transcriptases (RTs) are typically assayed in vitro with 5-10 mM Mg2+, whereas the free Mg2+ concentration in cells is much lower. Artificially high Mg2+ concentrations used in vitro can misrepresent different properties of human immunodeficiency virus (HIV) RT, including fidelity, catalysis, pausing, and RNase H activity. Here, we analyzed nucleoside (NRTIs) and non-nucleoside RT inhibitors (NNRTIs) in primer extension assays at different concentrations of free Mg2+. At low concentrations of Mg2+, NRTIs and dideoxynucleotides (AZTTP, ddCTP, ddGTP, and 3TCTP) inhibited HIV-1 and HIV-2 RT synthesis less efficiently than they did with large amounts of Mg2+, whereas inhibition by the "translocation-defective RT inhibitor" EFdA (4'-ethynyl-2-fluoro-2'-deoxyadenosine) was unaffected by Mg2+ concentrations. Steady-state kinetic analyses revealed that the reduced level of inhibition at low Mg2+ concentrations resulted from a 3-9-fold (depending on the particular nucleotide and inhibitor) less efficient incorporation (based on kcat/Km) of these NRTIs under this condition compared to incorporation of natural dNTPs. In contrast, EFdATP was incorporated with an efficiency similar to that of its analogue dATP at low Mg2+ concentrations. Unlike NRTIs, NNRTIs (nevirapine, efavirenz, and rilviripine), were approximately 4-fold (based on IC50 values) more effective at low than at high Mg2+ concentrations. Drug-resistant HIV-1 RT mutants also displayed the Mg2+-dependent difference in susceptibility to NRTIs and NNRTIs. In summary, analyzing the efficiency of inhibitors under more physiologically relevant low-Mg2+ conditions yielded results dramatically different from those from measurements using commonly employed high-Mg2+ in vitro conditions. These results also emphasize differences in Mg2+ sensitivity between the translocation inhibitor EFdATP and other NRTIs.
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Affiliation(s)
- Vasudevan Achuthan
- Cell Biology and Molecular Genetics, University of Maryland , College Park, Maryland 20742, United States.,Maryland Pathogen Research Institute , College Park, Maryland 20742, United States
| | - Kamlendra Singh
- Christopher S. Bond Life Sciences Center, University of Missouri , Columbia, Missouri 65211, United States.,Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine , Columbia, Missouri 65211, United States
| | - Jeffrey J DeStefano
- Cell Biology and Molecular Genetics, University of Maryland , College Park, Maryland 20742, United States.,Maryland Pathogen Research Institute , College Park, Maryland 20742, United States
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44
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Li A, Li J, Johnson KA. HIV-1 Reverse Transcriptase Polymerase and RNase H (Ribonuclease H) Active Sites Work Simultaneously and Independently. J Biol Chem 2016; 291:26566-26585. [PMID: 27777303 DOI: 10.1074/jbc.m116.753160] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 10/20/2016] [Indexed: 01/15/2023] Open
Abstract
HIV reverse transcriptase plays a central role in viral replication and requires coordination of both polymerase and RNase H activities. Although this coordination is crucial in viral replication, whether a DNA/RNA hybrid can simultaneously engage both active sites has yet to be determined as structural and kinetic analyses have provided contradictory results. Single nucleotide incorporation and RNase H cleavage were examined using presteady-state kinetics with global data analysis. The results revealed three interconverting reverse transcriptase-DNA/RNA species; 43% were active for both sites simultaneously, 27% showed only polymerase activity, and the remaining 30% were nonproductive. Our data clearly demonstrated that the DNA/RNA hybrid could contact both active sites simultaneously, although the single nucleotide incorporation (105 s-1) was ∼5-fold faster than the cleavage (23 s-1). By using a series of primers with different lengths, we found that a string of at least 4-6 nucleotides downstream of the cleaving site was required for efficient RNA cleavage. This was corroborated by our observations that during processive nucleotide incorporation, sequential rounds of RNA cleavage occurred each time after ∼6 nucleotides were incorporated. More importantly, during processive primer extension, pyrophosphate (PPi) release was rate-limiting so that the average rate of nucleotide incorporation (∼28 s-1) was comparable with that of net RNA cleavage (∼27 nucleotides(s)). Although polymerization is efficient and processive, RNase H is inefficient and periodic. This combination allows the two catalytic centers of HIVRT to work simultaneously at similar speeds without being tightly coupled.
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Affiliation(s)
- An Li
- From the The University of Texas at Austin, Institute for Cell and Molecular Biology, Department of Molecular Biosciences, Austin, Texas 78712
| | - Jiawen Li
- From the The University of Texas at Austin, Institute for Cell and Molecular Biology, Department of Molecular Biosciences, Austin, Texas 78712
| | - Kenneth A Johnson
- From the The University of Texas at Austin, Institute for Cell and Molecular Biology, Department of Molecular Biosciences, Austin, Texas 78712
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45
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Li A, Gong S, Johnson KA. Rate-limiting Pyrophosphate Release by HIV Reverse Transcriptase Improves Fidelity. J Biol Chem 2016; 291:26554-26565. [PMID: 27777304 DOI: 10.1074/jbc.m116.753152] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 10/20/2016] [Indexed: 11/06/2022] Open
Abstract
Previous measurements of the rates of polymerization and pyrophosphate release with DNA templates showed that pyrophosphate (PPi) dissociation was fast after nucleotide incorporation so that it did not contribute to enzyme specificity (kcat/Km). Here, kinetic parameters governing nucleotide incorporation and PPi release were determined using an RNA template. Compared with a DNA template of the same sequence, the rate of chemistry increased by up to 10-fold (250 versus 24 s-1), whereas the rate of PPi release decreased to approximately 58 s-1 so that PPi release became the rate-limiting step. During processive nucleotide incorporation, the first nucleotide (TTP) was incorporated at a fast rate (152 s-1), whereas the rates of incorporation of remaining nucleotides (CGTCG) were much slower with an average rate of 24 s-1, suggesting that sequential incorporation events were limited by the relatively slow PPi release step. The accompanying paper shows that slow PPi release allows polymerization and RNase H to occur at comparable rates. Although PPi release is the rate-determining step, it is not the specificity-determining step for correct incorporation based on our current estimates of the rate of reversal of the chemistry step (3 s-1). In contrast, during misincorporation, PPi release became extremely slow, which we estimated to be ∼0.002 s-1 These studies establish the mechanistic basis for DNA polymerase fidelity during reverse transcription and provide a free energy profile. We correct previous underestimates of discrimination by including the slow PPi release step. Our current estimate of 2.4 × 106 is >20-fold greater than estimated previously.
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Affiliation(s)
- An Li
- From the University of Texas at Austin, Institute for Cell and Molecular Biology, Department of Molecular Biosciences, Austin, Texas 78712
| | - Shanzhong Gong
- From the University of Texas at Austin, Institute for Cell and Molecular Biology, Department of Molecular Biosciences, Austin, Texas 78712
| | - Kenneth A Johnson
- From the University of Texas at Austin, Institute for Cell and Molecular Biology, Department of Molecular Biosciences, Austin, Texas 78712
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Zhang XM, Zhang Q, Wu H, Lau TCK, Liu X, Chu H, Zhang K, Zhou J, Chen ZW, Jin DY, Zheng BJ. Novel Mutations L228I and Y232H Cause Nonnucleoside Reverse Transcriptase Inhibitor Resistance in Combinational Pattern. AIDS Res Hum Retroviruses 2016; 32:909-17. [PMID: 27067022 DOI: 10.1089/aid.2015.0359] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The emergence of drug resistance mutations is increasing after the implementation of highly active antiretroviral therapy. To characterize two novel mutations L228I and Y232H in the primer grip of reverse transcriptase (RT) of HIV-1 circulating recombination form 08_BC (CRF08_BC) subtype, both mutant clones were constructed to determine their impacts on viral phenotypic susceptibility and replication capacity (RC). Results showed that the novel mutation, L228I, conferred a low-level resistance to etravirine by itself. L228I in combination with Y188C displayed a high level of cross-resistance to both nevirapine (NVP) and efavirenz (EFV). The copresence of A139V and Y232H induced a moderate level of resistance to NVP and EFV. Mutations Y188C/L228I, A139V, Y232H, and A139V/Y232H reduced more than 55% of viral RC compared with that of the wild-type (WT) reference virus. Modeling study suggested that the copresence of Y188C/L228I or A139V/Y232H might induce conformational changes to RT, which might result in reduced drug susceptibility and viral RC due to abolished hydrogen bonding or complex interaction with vicinal residues. Our results demonstrated that L228I and Y232H were novel accessory nonnucleoside reverse transcriptase inhibitor resistance-related mutations and provided valuable information for clinicians to design more effective treatment to patients infected with HIV-1 subtype CRF08_BC.
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Affiliation(s)
- Xiao-Min Zhang
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Qiwei Zhang
- Biosafety Level-3 Laboratory, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, China
| | - Hao Wu
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
- Guangzhou Center for Disease Control and Prevention, Guangzhou, China
| | - Terrence Chi-Kong Lau
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong SAR, China
| | - Xuan Liu
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong SAR, China
| | - Hin Chu
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Ke Zhang
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Jie Zhou
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Zhi-Wei Chen
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Dong-Yan Jin
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Bo-Jian Zheng
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
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Xu X, Thai H, Kitrinos KM, Xia G, Gaggar A, Paulson M, Ganova-Raeva L, Khudyakov Y, Lara J. Modeling the functional state of the reverse transcriptase of hepatitis B virus and its application to probing drug-protein interaction. BMC Bioinformatics 2016; 17 Suppl 8:280. [PMID: 27587008 PMCID: PMC5009823 DOI: 10.1186/s12859-016-1116-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Herein, the predicted atomic structures of five representative sequence variants of the reverse transcriptase protein (RT) of hepatitis B virus (HBV), sampled from patients with rapid or slow response to tenofovir disoproxil fumarate (TDF) treatment, have been examined to identify structural variations between them in order to assess structural and functional properties of HBV-RT variants associated with the differential responses to TDF treatment. RESULTS We utilized a hybrid computational approach to model the atomistic structures of HBV-RT/DNA-RNA/dATP and HBV-RT/DNA-RNA/TFV-DP (tenofovir diphosphate) complexes with the native hybrid DNA-RNA substrate in place. Multi-nanosecond molecular dynamics (MD) simulations of HBV-RT/DNA-RNA/dATP complexes revealed strong coupling of the natural nucleotide substrate, dATP, to the active site of the RT, and the differential involvement of the two putative magnesium cations (Mg(2+)) at the active site, whereby one Mg(2+) directly bridges the interaction between dATP and HBV-RT and the other serves as a coordinator to maintain an optimal configuration of the active site. Solvated interaction energy (SIE) calculated in MD simulations of HBV-RT/DNA-RNA/TFV-DP complexes indicate no differential binding affinity between TFV-DP and HBV-RT variants identified in patients with slow or rapid response to TDF treatment. CONCLUSION The predicted atomic structures accurately represent functional states of HBV-RT. The equivalent interaction between TFV-DP and each examined HBV-RT variants suggests that binding affinity of TFV-DP to HBV-RT is not associated with delayed viral clearance.
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Affiliation(s)
- Xiaojun Xu
- Division of Viral Hepatitis, National Center for HIV, Hepatitis, STD and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Hong Thai
- Division of Viral Hepatitis, National Center for HIV, Hepatitis, STD and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | | | - Guoliang Xia
- Division of Viral Hepatitis, National Center for HIV, Hepatitis, STD and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | | | | | - Lilia Ganova-Raeva
- Division of Viral Hepatitis, National Center for HIV, Hepatitis, STD and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Yury Khudyakov
- Division of Viral Hepatitis, National Center for HIV, Hepatitis, STD and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - James Lara
- Division of Viral Hepatitis, National Center for HIV, Hepatitis, STD and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA.
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48
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Cele FN, Ramesh M, Soliman ME. Per-residue energy decomposition pharmacophore model to enhance virtual screening in drug discovery: a study for identification of reverse transcriptase inhibitors as potential anti-HIV agents. DRUG DESIGN DEVELOPMENT AND THERAPY 2016; 10:1365-77. [PMID: 27114700 PMCID: PMC4833373 DOI: 10.2147/dddt.s95533] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A novel virtual screening approach is implemented herein, which is a further improvement of our previously published "target-bound pharmacophore modeling approach". The generated pharmacophore library is based only on highly contributing amino acid residues, instead of arbitrary pharmacophores, which are most commonly used in the conventional approaches in literature. Highly contributing amino acid residues were distinguished based on free binding energy contributions obtained from calculation from molecular dynamic (MD) simulations. To the best of our knowledge; this is the first attempt in the literature using such an approach; previous approaches have relied on the docking score to generate energy-based pharmacophore models. However, docking scores are reportedly unreliable. Thus, we present a model for a per-residue energy decomposition, constructed from MD simulation ensembles generating a more trustworthy pharmacophore model, which can be applied in drug discovery workflow. This work is aimed at introducing a more rational approach to the field of drug design, rather than comparing the validity of this approach against those previously reported. We recommend additional computational and experimental work to further validate this approach. This approach was used to screen for potential reverse transcriptase inhibitors using the pharmacophoric features of compound GSK952. The complex was subjected to docking, thereafter, MD simulation confirmed the stability of the system. Experimentally determined inhibitors with known HIV-reverse transcriptase inhibitory activity were used to validate the protocol. Two potential hits (ZINC46849657 and ZINC54359621) showed a significant potential with regard to free binding energy. Reported results obtained from this work confirm that this new approach is favorable in the future of the drug design industry.
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Affiliation(s)
- Favourite N Cele
- Molecular Modelling and Drug Design Research Group, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Muthusamy Ramesh
- Molecular Modelling and Drug Design Research Group, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Mahmoud Es Soliman
- Molecular Modelling and Drug Design Research Group, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
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49
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Yadahalli S, Gosavi S. Functionally Relevant Specific Packing Can Determine Protein Folding Routes. J Mol Biol 2015; 428:509-21. [PMID: 26724535 DOI: 10.1016/j.jmb.2015.12.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 11/26/2015] [Accepted: 12/18/2015] [Indexed: 10/22/2022]
Abstract
Functional residues can modulate the folding mechanisms of proteins. In some proteins, mutations to such residues can radically change the primary folding route. Is it possible then to learn more about the functional regions of a protein by investigating just its choice of folding route? The folding and the function of the protein Escherichia coli ribonuclease H (ecoRNase-H) have been extensively studied and its folding route is known to near-residue resolution. Here, we computationally study the folding of ecoRNase-H using molecular dynamics simulations of structure-based models of increasing complexity. The differences between a model that correctly predicts the experimentally determined folding route and a simpler model that does not can be attributed to a set of six aromatic residues clustered together in a region of the protein called CORE. This clustering, which we term "specific" packing, drives CORE to fold early and determines the folding route. Both the residues involved in specific packing and their packing are largely conserved across E. coli-like RNase-Hs from diverse species. Residue conservation is usually implicated in function. Here, the identified residues either are known to bind substrate in ecoRNase-H or pack against the substrate in the homologous human RNase-H where a substrate-bound crystal structure exists. Thus, the folding mechanism of ecoRNase-H is a byproduct of functional demands upon its sequence. Using our observations on specific packing, we suggest mutations to an engineered HIV RNase-H to make its function better. Our results show that understanding folding route choice in proteins can provide unexpected insights into their function.
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Affiliation(s)
- Shilpa Yadahalli
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bellary Road, Bangalore 560065, India; Manipal University, Madhav Nagar, Manipal 576104, India; Bioinformatics Institute (A*STAR), Singapore 138671, Singapore
| | - Shachi Gosavi
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bellary Road, Bangalore 560065, India.
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50
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Miller MT, Tuske S, Das K, DeStefano JJ, Arnold E. Structure of HIV-1 reverse transcriptase bound to a novel 38-mer hairpin template-primer DNA aptamer. Protein Sci 2015; 25:46-55. [PMID: 26296781 DOI: 10.1002/pro.2776] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 08/19/2015] [Accepted: 08/20/2015] [Indexed: 01/09/2023]
Abstract
The development of a modified DNA aptamer that binds HIV-1 reverse transcriptase (RT) with ultra-high affinity has enabled the X-ray structure determination of an HIV-1 RT-DNA complex to 2.3 Å resolution without the need for an antibody Fab fragment or RT-DNA cross-linking. The 38-mer hairpin-DNA aptamer has a 15 base-pair duplex, a three-deoxythymidine hairpin loop, and a five-nucleotide 5'-overhang. The aptamer binds RT in a template-primer configuration with the 3'-end positioned at the polymerase active site and has 2'-O-methyl modifications at the second and fourth duplex template nucleotides that interact with the p66 fingers and palm subdomains. This structure represents the highest resolution RT-nucleic acid structure to date. The RT-aptamer complex is catalytically active and can serve as a platform for studying fundamental RT mechanisms and for development of anti-HIV inhibitors through fragment screening and other approaches. Additionally, the structure allows for a detailed look at a unique aptamer design and provides the molecular basis for its remarkably high affinity for RT.
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Affiliation(s)
- Matthew T Miller
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854
| | - Steve Tuske
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854
| | - Kalyan Das
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854
| | - Jeffrey J DeStefano
- Department of Cell Biology and Molecular Genetics, University of Maryland College Park, College Park, Maryland, 20742
| | - Eddy Arnold
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854
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