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Heng X, Herrera AP, Song Z, Boris-Lawrie K. Retroviral PBS-segment sequence and structure: Orchestrating early and late replication events. Retrovirology 2024; 21:12. [PMID: 38886829 PMCID: PMC11181671 DOI: 10.1186/s12977-024-00646-x] [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: 02/29/2024] [Accepted: 06/06/2024] [Indexed: 06/20/2024] Open
Abstract
An essential regulatory hub for retroviral replication events, the 5' untranslated region (UTR) encodes an ensemble of cis-acting replication elements that overlap in a logical manner to carry out divergent RNA activities in cells and in virions. The primer binding site (PBS) and primer activation sequence initiate the reverse transcription process in virions, yet overlap with structural elements that regulate expression of the complex viral proteome. PBS-segment also encompasses the attachment site for Integrase to cut and paste the 3' long terminal repeat into the host chromosome to form the provirus and purine residues necessary to execute the precise stoichiometry of genome-length transcripts and spliced viral RNAs. Recent genetic mapping, cofactor affinity experiments, NMR and SAXS have elucidated that the HIV-1 PBS-segment folds into a three-way junction structure. The three-way junction structure is recognized by the host's nuclear RNA helicase A/DHX9 (RHA). RHA tethers host trimethyl guanosine synthase 1 to the Rev/Rev responsive element (RRE)-containing RNAs for m7-guanosine Cap hyper methylation that bolsters virion infectivity significantly. The HIV-1 trimethylated (TMG) Cap licenses specialized translation of virion proteins under conditions that repress translation of the regulatory proteins. Clearly host-adaption and RNA shapeshifting comprise the fundamental basis for PBS-segment orchestrating both reverse transcription of virion RNA and the nuclear modification of m7G-Cap for biphasic translation of the complex viral proteome. These recent observations, which have exposed even greater complexity of retroviral RNA biology than previously established, are the impetus for this article. Basic research to fully comprehend the marriage of PBS-segment structures and host RNA binding proteins that carry out retroviral early and late replication events is likely to expose an immutable virus-specific therapeutic target to attenuate retrovirus proliferation.
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Affiliation(s)
- Xiao Heng
- Department of Biochemistry, University of Missouri, Columbia, MO, 65211, USA.
| | - Amanda Paz Herrera
- Department of Biochemistry, University of Missouri, Columbia, MO, 65211, USA
| | - Zhenwei Song
- Department of Veterinary and Biomedical Sciences, Institute for Molecular Virology, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Kathleen Boris-Lawrie
- Department of Veterinary and Biomedical Sciences, Institute for Molecular Virology, University of Minnesota, Saint Paul, MN, 55108, USA.
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2
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Laitinen T, Meili T, Koyioni M, Koutentis PA, Poso A, Hofmann-Lehmann R, Asquith CRM. Synthesis and evaluation of 1,2,3-dithiazole inhibitors of the nucleocapsid protein of feline immunodeficiency virus (FIV) as a model for HIV infection. Bioorg Med Chem 2022; 68:116834. [PMID: 35653871 DOI: 10.1016/j.bmc.2022.116834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/13/2022] [Accepted: 05/13/2022] [Indexed: 11/17/2022]
Abstract
We disclose a series of potent anti-viral 1,2,3-dithiazoles, accessed through a succinct synthetic approach from 4,5-dichloro-1,2,3-dithiazolium chloride (Appel's salt). A series of small libraries of compounds were screened against feline immunodeficiency virus (FIV) infected cells as a model for HIV. This approach highlighted new structure activity relationship understanding and led to the development of sub-micro molar anti-viral compounds with reduced toxicity. In addition, insight into the mechanistic progress of this system is provided via advanced QM-MM modelling. The 1,2,3-dithiazole represents a versatile scaffold with potential for further development to treat both FIV and HIV.
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Affiliation(s)
- Tuomo Laitinen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70211 Kuopio, Finland
| | - Theres Meili
- Clinical Laboratory, Department of Clinical Diagnostics and Services, and Center for Clinical Studies, Vetsuisse Faculty, University of Zurich, Zurich 8057, Switzerland
| | - Maria Koyioni
- Department of Chemistry, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus
| | | | - Antti Poso
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70211 Kuopio, Finland; Department of Internal Medicine VIII, University Hospital Tübingen, Otfried-Müller-Strasse 14, 72076 Tübingen, Germany
| | - Regina Hofmann-Lehmann
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70211 Kuopio, Finland
| | - Christopher R M Asquith
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70211 Kuopio, Finland; Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, NC 27599, USA.
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3
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Wang R, Wei Y, Wang M, Yan P, Jiang H, Du Z. Interaction of Natural Compounds in Licorice and Turmeric with HIV-NCp7 Zinc Finger Domain: Potential Relevance to the Mechanism of Antiviral Activity. Molecules 2021; 26:molecules26123563. [PMID: 34200973 PMCID: PMC8230585 DOI: 10.3390/molecules26123563] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/28/2021] [Accepted: 06/09/2021] [Indexed: 01/10/2023] Open
Abstract
Nucleocapsid proteins (NCp) are zinc finger (ZF) proteins, and they play a central role in HIV virus replication, mainly by interacting with nucleic acids. Therefore, they are potential targets for anti-HIV therapy. Natural products have been shown to be able to inhibit HIV, such as turmeric and licorice, which is widely used in traditional Chinese medicine. Liquiritin (LQ), isoliquiritin (ILQ), glycyrrhizic acid (GL), glycyrrhetinic acid (GA) and curcumin (CUR), which were the major active components, were herein chosen to study their interactions with HIV-NCp7 C-terminal zinc finger, aiming to find the potential active compounds and reveal the mechanism involved. The stacking interaction between NCp7 tryptophan and natural compounds was evaluated by fluorescence. To elucidate the binding mode, mass spectrometry was used to characterize the reaction mixture between zinc finger proteins and active compounds. Subsequently, circular dichroism (CD) spectroscopy and molecular docking were used to validate and reveal the binding mode from a structural perspective. The results showed that ILQ has the strongest binding ability among the tested compounds, followed by curcumin, and the interaction between ILQ and the NCp7 zinc finger peptide was mediated by a noncovalent interaction. This study provided a scientific basis for the antiviral activity of turmeric and licorice.
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Affiliation(s)
- Runjing Wang
- Tongji School of Pharmacy, Huazhong University of Science and Technology, Wuhan 430030, China; (R.W.); (Y.W.); (M.W.); (P.Y.); (H.J.)
- Ningxia Pharmaceutical Inspection and Research Institute, Yinchuan 750001, China
| | - Yinyu Wei
- Tongji School of Pharmacy, Huazhong University of Science and Technology, Wuhan 430030, China; (R.W.); (Y.W.); (M.W.); (P.Y.); (H.J.)
| | - Meiqin Wang
- Tongji School of Pharmacy, Huazhong University of Science and Technology, Wuhan 430030, China; (R.W.); (Y.W.); (M.W.); (P.Y.); (H.J.)
| | - Pan Yan
- Tongji School of Pharmacy, Huazhong University of Science and Technology, Wuhan 430030, China; (R.W.); (Y.W.); (M.W.); (P.Y.); (H.J.)
| | - Hongliang Jiang
- Tongji School of Pharmacy, Huazhong University of Science and Technology, Wuhan 430030, China; (R.W.); (Y.W.); (M.W.); (P.Y.); (H.J.)
| | - Zhifeng Du
- Tongji School of Pharmacy, Huazhong University of Science and Technology, Wuhan 430030, China; (R.W.); (Y.W.); (M.W.); (P.Y.); (H.J.)
- Correspondence:
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4
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Mouhand A, Pasi M, Catala M, Zargarian L, Belfetmi A, Barraud P, Mauffret O, Tisné C. Overview of the Nucleic-Acid Binding Properties of the HIV-1 Nucleocapsid Protein in Its Different Maturation States. Viruses 2020; 12:v12101109. [PMID: 33003650 PMCID: PMC7601788 DOI: 10.3390/v12101109] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/23/2020] [Accepted: 09/26/2020] [Indexed: 12/17/2022] Open
Abstract
HIV-1 Gag polyprotein orchestrates the assembly of viral particles. Its C-terminus consists of the nucleocapsid (NC) domain that interacts with nucleic acids, and p1 and p6, two unstructured regions, p6 containing the motifs to bind ALIX, the cellular ESCRT factor TSG101 and the viral protein Vpr. The processing of Gag by the viral protease subsequently liberates NCp15 (NC-p1-p6), NCp9 (NC-p1) and NCp7, NCp7 displaying the optimal chaperone activity of nucleic acids. This review focuses on the nucleic acid binding properties of the NC domain in the different maturation states during the HIV-1 viral cycle.
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Affiliation(s)
- Assia Mouhand
- Expression Génétique Microbienne, UMR 8261, CNRS, Université de Paris, Institut de Biologie Physico-Chimique (IBPC), 75005 Paris, France; (A.M.); (M.C.); (P.B.)
| | - Marco Pasi
- Laboratoire de Biologie et de Pharmacologie Appliquée (LBPA), UMR 8113 CNRS, Institut D’Alembert, École Normale Supérieure Paris-Saclay, Université Paris-Saclay, 4, Avenue des Sciences, 91190 Gif sur Yvette, France; (M.P.); (L.Z.); (A.B.)
| | - Marjorie Catala
- Expression Génétique Microbienne, UMR 8261, CNRS, Université de Paris, Institut de Biologie Physico-Chimique (IBPC), 75005 Paris, France; (A.M.); (M.C.); (P.B.)
| | - Loussiné Zargarian
- Laboratoire de Biologie et de Pharmacologie Appliquée (LBPA), UMR 8113 CNRS, Institut D’Alembert, École Normale Supérieure Paris-Saclay, Université Paris-Saclay, 4, Avenue des Sciences, 91190 Gif sur Yvette, France; (M.P.); (L.Z.); (A.B.)
| | - Anissa Belfetmi
- Laboratoire de Biologie et de Pharmacologie Appliquée (LBPA), UMR 8113 CNRS, Institut D’Alembert, École Normale Supérieure Paris-Saclay, Université Paris-Saclay, 4, Avenue des Sciences, 91190 Gif sur Yvette, France; (M.P.); (L.Z.); (A.B.)
| | - Pierre Barraud
- Expression Génétique Microbienne, UMR 8261, CNRS, Université de Paris, Institut de Biologie Physico-Chimique (IBPC), 75005 Paris, France; (A.M.); (M.C.); (P.B.)
| | - Olivier Mauffret
- Laboratoire de Biologie et de Pharmacologie Appliquée (LBPA), UMR 8113 CNRS, Institut D’Alembert, École Normale Supérieure Paris-Saclay, Université Paris-Saclay, 4, Avenue des Sciences, 91190 Gif sur Yvette, France; (M.P.); (L.Z.); (A.B.)
- Correspondence: (O.M.); (C.T.)
| | - Carine Tisné
- Expression Génétique Microbienne, UMR 8261, CNRS, Université de Paris, Institut de Biologie Physico-Chimique (IBPC), 75005 Paris, France; (A.M.); (M.C.); (P.B.)
- Correspondence: (O.M.); (C.T.)
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Humbert N, Kovalenko L, Saladini F, Giannini A, Pires M, Botzanowski T, Cherenok S, Boudier C, Sharma KK, Real E, Zaporozhets OA, Cianférani S, Seguin-Devaux C, Poggialini F, Botta M, Zazzi M, Kalchenko VI, Mori M, Mély Y. (Thia)calixarenephosphonic Acids as Potent Inhibitors of the Nucleic Acid Chaperone Activity of the HIV-1 Nucleocapsid Protein with a New Binding Mode and Multitarget Antiviral Activity. ACS Infect Dis 2020; 6:687-702. [PMID: 32045204 DOI: 10.1021/acsinfecdis.9b00290] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The nucleocapsid protein (NC) is a highly conserved protein that plays key roles in HIV-1 replication through its nucleic acid chaperone properties mediated by its two zinc fingers and basic residues. NC is a promising target for antiviral therapy, particularly to control viral strains resistant to currently available drugs. Since calixarenes with antiviral properties have been described, we explored the ability of calixarene hydroxymethylphosphonic or sulfonic acids to inhibit NC chaperone properties and exhibit antiviral activity. By using fluorescence-based assays, we selected four calixarenes inhibiting NC chaperone activity with submicromolar IC50 values. These compounds were further shown by mass spectrometry, isothermal titration calorimetry, and fluorescence anisotropy to bind NC with no zinc ejection and to compete with nucleic acids for the binding to NC. Molecular dynamic simulations further indicated that these compounds interact via their phosphonate or sulfonate groups with the basic surface of NC but not with the hydrophobic plateau at the top of the folded fingers. Cellular studies showed that the most soluble compound CIP201 inhibited the infectivity of wild-type and drug-resistant HIV-1 strains at low micromolar concentrations, primarily targeting the early steps of HIV-1 replication. Moreover, CIP201 was also found to inhibit the flipping and polymerization activity of reverse transcriptase. Calixarenes thus form a class of noncovalent NC inhibitors, endowed with a new binding mode and multitarget antiviral activity.
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Affiliation(s)
- Nicolas Humbert
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
| | - Lesia Kovalenko
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
- Department of Chemistry, Taras Shevchenko National University of Kyiv, 01601 Kyiv, Ukraine
| | - Francesco Saladini
- Department of Medical Biotechnologies, University of Siena, viale Mario Bracci no. 16, 53100 Siena, Italy
| | - Alessia Giannini
- Department of Medical Biotechnologies, University of Siena, viale Mario Bracci no. 16, 53100 Siena, Italy
| | - Manuel Pires
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
| | - Thomas Botzanowski
- Laboratoire de Spectrométrie de Masse BioOrganique, IPHC UMR 7178 CNRS, Université de Strasbourg, 67000 Strasbourg, France
| | - Sergiy Cherenok
- Institute of Organic Chemistry, National Academy of Science of Ukraine, Murmanska str. 5, Kyiv 02660, Ukraine
| | - Christian Boudier
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
| | - Kamal K. Sharma
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
| | - Eleonore Real
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
| | - Olga A. Zaporozhets
- Department of Chemistry, Taras Shevchenko National University of Kyiv, 01601 Kyiv, Ukraine
| | - Sarah Cianférani
- Laboratoire de Spectrométrie de Masse BioOrganique, IPHC UMR 7178 CNRS, Université de Strasbourg, 67000 Strasbourg, France
| | - Carole Seguin-Devaux
- Department of Infection and Immunity, Luxembourg Institute of Health, 29 rue Henri Koch, L-4354 Esch-sur-Alzette, Luxembourg
| | - Federica Poggialini
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018-2022 Università degli Studi di Siena, via Aldo Moro 2, I-53019 Siena, Italy
| | - Maurizio Botta
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018-2022 Università degli Studi di Siena, via Aldo Moro 2, I-53019 Siena, Italy
| | - Maurizio Zazzi
- Department of Medical Biotechnologies, University of Siena, viale Mario Bracci no. 16, 53100 Siena, Italy
| | - Vitaly I. Kalchenko
- Institute of Organic Chemistry, National Academy of Science of Ukraine, Murmanska str. 5, Kyiv 02660, Ukraine
| | - Mattia Mori
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018-2022 Università degli Studi di Siena, via Aldo Moro 2, I-53019 Siena, Italy
| | - Yves Mély
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
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6
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Asquith CRM, Meili T, Laitinen T, Baranovsky IV, Konstantinova LS, Poso A, Rakitin OA, Hofmann-Lehmann R. Synthesis and comparison of substituted 1,2,3-dithiazole and 1,2,3-thiaselenazole as inhibitors of the feline immunodeficiency virus (FIV) nucleocapsid protein as a model for HIV infection. Bioorg Med Chem Lett 2019; 29:1765-1768. [PMID: 31101470 DOI: 10.1016/j.bmcl.2019.05.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 05/08/2019] [Indexed: 01/30/2023]
Abstract
We report the first biological evaluation the 1,2,3-thiaselenazole class of compound and utilising a concise synthetic approach of sulfur extrusion, selenium insertion of the 1,2,3-dithiazoles. We created a small diverse library of compounds to contrast the two ring systems. This approach has highlighted new structure activity relationship insights and lead to the development of sub-micro molar anti-viral compounds with reduced toxicity. The 1,2,3-thiaselenazole represents a new class of potential compounds for the treatment of FIV and HIV.
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Affiliation(s)
- Christopher R M Asquith
- Department of Pharmacology, School of Medicine University of North Carolina at Chapel Hill, NC 27599, USA.
| | - Theres Meili
- Clinical Laboratory and Center for Clinical Studies, Vetsuisse Faculty, University of Zurich, Zurich 8057, Switzerland
| | - Tuomo Laitinen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio 70211, Finland
| | - Ilia V Baranovsky
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russian Federation
| | - Lidia S Konstantinova
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russian Federation; Nanotechnology Education and Research Center, South Ural State University, Lenina Ave. 76, Chelyabinsk 454080, Russian Federation
| | - Antti Poso
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russian Federation
| | - Oleg A Rakitin
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russian Federation; Nanotechnology Education and Research Center, South Ural State University, Lenina Ave. 76, Chelyabinsk 454080, Russian Federation
| | - Regina Hofmann-Lehmann
- Clinical Laboratory and Center for Clinical Studies, Vetsuisse Faculty, University of Zurich, Zurich 8057, Switzerland
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7
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Asquith CRM, Konstantinova LS, Laitinen T, Meli ML, Poso A, Rakitin OA, Hofmann-Lehmann R, Hilton ST. Evaluation of Substituted 1,2,3-Dithiazoles as Inhibitors of the Feline Immunodeficiency Virus (FIV) Nucleocapsid Protein via a Proposed Zinc Ejection Mechanism. ChemMedChem 2016; 11:2119-2126. [DOI: 10.1002/cmdc.201600260] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/21/2016] [Indexed: 12/20/2022]
Affiliation(s)
- Christopher R. M. Asquith
- School of Pharmacy; Faculty of Life Sciences; University College London; London WC1N 1AX UK
- Clinical Laboratory & Center for Clinical Studies; Vetsuisse Faculty; University of Zurich; 8057 Zurich Switzerland
| | - Lidia S. Konstantinova
- Zelinsky Institute of Organic Chemistry; Russian Academy of Sciences; Moscow 119991 Russian Federation
- Nanotechnology Education and Research Center; South Ural State, University; Lenina Ave. 76 Chelyabinsk 454080 Russian Federation
| | - Tuomo Laitinen
- School of Pharmacy; Faculty of Health Sciences; University of Eastern, Finland; Kuopio 70211 Finland
| | - Marina L. Meli
- Clinical Laboratory & Center for Clinical Studies; Vetsuisse Faculty; University of Zurich; 8057 Zurich Switzerland
| | - Antti Poso
- School of Pharmacy; Faculty of Health Sciences; University of Eastern, Finland; Kuopio 70211 Finland
| | - Oleg A. Rakitin
- Zelinsky Institute of Organic Chemistry; Russian Academy of Sciences; Moscow 119991 Russian Federation
- Nanotechnology Education and Research Center; South Ural State, University; Lenina Ave. 76 Chelyabinsk 454080 Russian Federation
| | - Regina Hofmann-Lehmann
- Clinical Laboratory & Center for Clinical Studies; Vetsuisse Faculty; University of Zurich; 8057 Zurich Switzerland
| | - Stephen T. Hilton
- School of Pharmacy; Faculty of Life Sciences; University College London; London WC1N 1AX UK
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8
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Asquith CRM, Meli ML, Konstantinova LS, Laitinen T, Poso A, Rakitin OA, Hofmann-Lehmann R, Allenspach K, Hilton ST. Novel fused tetrathiocines as antivirals that target the nucleocapsid zinc finger containing protein of the feline immunodeficiency virus (FIV) as a model of HIV infection. Bioorg Med Chem Lett 2014; 25:1352-5. [PMID: 25702849 DOI: 10.1016/j.bmcl.2014.12.047] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 12/12/2014] [Accepted: 12/13/2014] [Indexed: 01/06/2023]
Abstract
A novel series of fused tetrathiocines were prepared for evaluation of activity against the nucleocapsid protein of the feline immunodeficiency virus (FIV) in an in vitro cell culture approach. The results demonstrated that the compounds display potent nanomolar activity and low toxicity against this key model of HIV infection.
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Affiliation(s)
- Christopher R M Asquith
- UCL School of Pharmacy, Faculty of Life Sciences, University College London, London WC1N 1AX, United Kingdom
| | - Marina L Meli
- Clinical Laboratory and Center for Clinical Studies, Vetsuisse Faculty, University of Zurich, Zurich 8057, Switzerland
| | - Lidia S Konstantinova
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russian Federation
| | - Tuomo Laitinen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70211 Kuopio, Finland
| | - Antti Poso
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70211 Kuopio, Finland
| | - Oleg A Rakitin
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russian Federation
| | - Regina Hofmann-Lehmann
- Clinical Laboratory and Center for Clinical Studies, Vetsuisse Faculty, University of Zurich, Zurich 8057, Switzerland
| | - Karin Allenspach
- Veterinary Clinical Sciences, Royal Veterinary College, Hatfield AL9 7TA, United Kingdom
| | - Stephen T Hilton
- UCL School of Pharmacy, Faculty of Life Sciences, University College London, London WC1N 1AX, United Kingdom.
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9
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Wu H, Mitra M, McCauley MJ, Thomas JA, Rouzina I, Musier-Forsyth K, Williams MC, Gorelick RJ. Aromatic residue mutations reveal direct correlation between HIV-1 nucleocapsid protein's nucleic acid chaperone activity and retroviral replication. Virus Res 2013; 171:263-77. [PMID: 22814429 PMCID: PMC3745225 DOI: 10.1016/j.virusres.2012.07.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 07/02/2012] [Accepted: 07/07/2012] [Indexed: 10/28/2022]
Abstract
The human immunodeficiency virus type 1 (HIV-1) nucleocapsid (NC) protein plays an essential role in several stages of HIV-1 replication. One important function of HIV-1 NC is to act as a nucleic acid chaperone, in which the protein facilitates nucleic acid rearrangements important for reverse transcription and recombination. NC contains only 55 amino acids, with 15 basic residues and two zinc fingers, each having a single aromatic residue (Phe16 and Trp37). Despite its simple structure, HIV-1 NC appears to have optimal chaperone activity, including the ability to strongly aggregate nucleic acids, destabilize nucleic acid secondary structure, and facilitate rapid nucleic acid annealing. Here we combine single molecule DNA stretching experiments with ensemble solution studies of protein-nucleic acid binding affinity, oligonucleotide annealing, and nucleic acid aggregation to measure the characteristics of wild-type (WT) and aromatic residue mutants of HIV-1 NC that are important for nucleic acid chaperone activity. These in vitro results are compared to in vivo HIV-1 replication for viruses containing the same mutations. This work allows us to directly relate HIV-1 NC structure with its function as a nucleic acid chaperone in vitro and in vivo. We show that replacement of either aromatic residue with another aromatic residue results in a protein that strongly resembles WT NC. In contrast, single amino acid substitutions of either Phe16Ala or Trp37Ala significantly slow down NC's DNA interaction kinetics, while retaining some helix-destabilization capability. A double Phe16Ala/Trp37Ala substitution further reduces the latter activity. Surprisingly, the ensemble nucleic acid binding, annealing, and aggregation properties are not significantly altered for any mutant except the double aromatic substitution with Ala. Thus, elimination of a single aromatic residue from either zinc finger strongly reduces NC's chaperone activity as determined by single molecule DNA stretching experiments without significantly altering its ensemble-averaged biochemical properties. Importantly, the substitution of aromatic residues with Ala progressively decreases NC's nucleic acid chaperone activity while also progressively inhibiting viral replication. Taken together, these data support the critical role of HIV-1 NC's aromatic residues, and establish a direct and statistically significant correlation between nucleic acid chaperone activity and viral replication.
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Affiliation(s)
- Hao Wu
- Northeastern University, Department of Physics, Boston, MA 02115, USA
| | - Mithun Mitra
- The Ohio State University, Department of Chemistry and Biochemistry, Center for Retrovirus Research, Center for RNA Biology, Columbus, OH 43210, USA
| | - Micah J. McCauley
- Northeastern University, Department of Physics, Boston, MA 02115, USA
| | - James A. Thomas
- AIDS and Cancer Virus Program, SAIC-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Ioulia Rouzina
- University of Minnesota, Department of Biochemistry, Molecular Biology, and Biophysics, Minneapolis, MN 55455, USA
| | - Karin Musier-Forsyth
- The Ohio State University, Department of Chemistry and Biochemistry, Center for Retrovirus Research, Center for RNA Biology, Columbus, OH 43210, USA
| | - Mark C. Williams
- Northeastern University, Department of Physics, Boston, MA 02115, USA
| | - Robert J. Gorelick
- AIDS and Cancer Virus Program, SAIC-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
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Nucleocapsid protein annealing of a primer-template enhances (+)-strand DNA synthesis and fidelity by HIV-1 reverse transcriptase. J Mol Biol 2011; 415:866-80. [PMID: 22210155 DOI: 10.1016/j.jmb.2011.12.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 12/09/2011] [Accepted: 12/16/2011] [Indexed: 11/22/2022]
Abstract
Human immunodeficiency virus type 1 (HIV-1) requires reverse transcriptase (RT) and HIV-1 nucleocapsid protein (NCp7) for proper viral replication. HIV-1 NCp7 has been shown to enhance various steps in reverse transcription including tRNA initiation and strand transfer, which may be mediated through interactions with RT as well as RNA and DNA oligonucleotides. With the use of DNA oligonucleotides, we have examined the interaction of NCp7 with RT and the kinetics of reverse transcription during (+)-strand synthesis with an NCp7-facilitated annealed primer-template. Through the use of a pre-steady-state kinetics approach, the NCp7-annealed primer-template has a substantial increase (3- to 7-fold) in the rate of incorporation (k(pol)) by RT as compared to heat-annealed primer-template with single-nucleotide incorporation. There was also a 2-fold increase in the binding affinity constant (K(d)) of the nucleotide. These differences in k(pol) and K(d) were not through direct interactions between HIV-1 RT and NCp7. When extension by RT was examined, the data suggest that the NCp7-annealed primer-template facilitates the formation of a longer product more quickly compared to the heat-annealed primer-template. This enhancement in rate is mediated through interactions with NCp7's zinc fingers and N-terminal domain and nucleic acids. The NCp7-annealed primer-template also enhances the fidelity of RT (3-fold) by slowing the rate of incorporation of an incorrect nucleotide. Taken together, this study elucidates a new role of NCp7 by facilitating DNA-directed DNA synthesis during reverse transcription by HIV-1 RT that may translate into enhanced viral fitness and offers an avenue to exploit for targeted therapeutic intervention against HIV.
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11
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Jalalirad M, Laughrea M. Formation of immature and mature genomic RNA dimers in wild-type and protease-inactive HIV-1: differential roles of the Gag polyprotein, nucleocapsid proteins NCp15, NCp9, NCp7, and the dimerization initiation site. Virology 2010; 407:225-36. [PMID: 20828778 DOI: 10.1016/j.virol.2010.08.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 08/06/2010] [Accepted: 08/13/2010] [Indexed: 12/22/2022]
Abstract
Formation of immature genomic RNA (gRNA) dimers is exquisitely nucleocapsid (NC)-dependent in protease-inactive (PR-in) HIV-1. This establishes that Pr55gag/Pr160gag-pol has NC-dependent chaperone activity within intact HIV-1. Mutations in the proximal zinc finger and the linker of the NC sequence of Pr55gag/Pr160gag-pol abolish gRNA dimerization in PR-in HIV-1. In wild type, where the NC of Pr55gag is processed into progressively smaller proteins termed NCp15 (NCp7-p1-p6), NCp9 (NCp7-p1) and NCp7, formation of immature dimers is much swifter than in PR-in HIV-1. NCp7 and NCp15 direct this rapid accumulation. NCp9 is sluggish in this process, but it stimulates the transition from immature to mature gRNA dimer as well as NCp7 and much better than NCp15. The amino-terminus, proximal zinc finger, linker, and distal zinc finger of NCp7 contribute to this maturation event in intact HIV-1. The DIS is a dimerization initiation site for all immature gRNA dimers, irrespective of their mechanism of formation.
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Affiliation(s)
- Mohammad Jalalirad
- McGill AIDS Center, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal QC, Canada H3T 1E2
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12
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How the HIV-1 nucleocapsid protein binds and destabilises the (-)primer binding site during reverse transcription. J Mol Biol 2008; 383:1112-28. [PMID: 18773912 DOI: 10.1016/j.jmb.2008.08.046] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Accepted: 08/19/2008] [Indexed: 10/21/2022]
Abstract
The human immunodeficiency virus type 1 nucleocapsid protein (NCp7) plays an important role in the second strand transfer during reverse transcription. It promotes annealing of the 18-nucleotide complementary DNA primer-binding site (PBS) sequences at the 3' ends of (-)DNA and (+)DNA. NMR studies show that NCp7(12-55) and NCp7(1-55) interact at the 5' end of the loop of DeltaP(-)PBS, a (-)PBS derivative without the 3' protruding sequence, in a slow-exchange equilibrium. This interaction is mediated through the binding of the hydrophobic plateau (Val13, Phe16, Thr24, Ala25, Trp37, and Met46) on the zinc finger domain of both peptides to the 5-CTG-7 sequence of DeltaP(-)PBS. The stacking of the Trp37 aromatic ring with the G7 residue likely constitutes the determinant factor of the interaction. Although NCp7(12-55) does not melt the DeltaP(-)PBS stem-loop structure, it opens the loop and weakens the C5.G11 base pair next to the loop. Moreover, NCp7(12-55) was also found to bind but with lower affinity to the 10-CGG-12 sequence in an intermediate-exchange equilibrium on the NMR time scale. The loop modifications may favour a kissing interaction with the complementary (+)PBS loop. Moreover, the weakening of the upper base pair of the stem likely promotes the melting of the stem that is required to convert the kissing complex into the final (+/-)PBS extended duplex.
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13
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Avilov SV, Piemont E, Shvadchak V, de Rocquigny H, Mély Y. Probing dynamics of HIV-1 nucleocapsid protein/target hexanucleotide complexes by 2-aminopurine. Nucleic Acids Res 2007; 36:885-96. [PMID: 18086707 PMCID: PMC2241888 DOI: 10.1093/nar/gkm1109] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The nucleocapsid protein (NC) plays an important role in HIV-1, mainly through interactions with the genomic RNA and its DNA copies. Though the structures of several complexes of NC with oligonucleotides (ODNs) are known, detailed information on the ODN dynamics in the complexes is missing. To address this, we investigated the steady state and time-resolved fluorescence properties of 2-aminopurine (2Ap), a fluorescent adenine analog introduced at positions 2 and 5 of AACGCC and AATGCC sequences. In the absence of NC, 2Ap fluorescence was strongly quenched in the flexible ODNs, mainly through picosecond to nanosecond dynamic quenching by its neighboring bases. NC strongly restricted the ODN flexibility and 2Ap local mobility, impeding the collisions of 2Ap with its neighbors and thus, reducing its dynamic quenching. Phe16→Ala and Trp37→Leu mutations largely decreased the ability of NC to affect the local dynamics of 2Ap at positions 2 and 5, respectively, while a fingerless NC was totally ineffective. The restriction of 2Ap local mobility was thus associated with the NC hydrophobic platform at the top of the folded fingers. Since this platform supports the NC chaperone properties, the restriction of the local mobility of the bases is likely a mechanistic component of these properties.
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Affiliation(s)
- S V Avilov
- Institut Gilbert-Laustriat, UMR 7175 CNRS/Université Louis Pasteur (Strasbourg I), Dépt. Pharmacologie et Physicochimie, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
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14
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Bombarda E, Grell E, Roques BP, Mély Y. Molecular mechanism of the Zn2+-induced folding of the distal CCHC finger motif of the HIV-1 nucleocapsid protein. Biophys J 2007; 93:208-17. [PMID: 17416621 PMCID: PMC1914429 DOI: 10.1529/biophysj.106.101378] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
HIV-1 nucleocapsid protein, NCp7, contains two highly conserved CCHC zinc fingers. Binding of Zn(2+) drives NCp7 from an unfolded to a highly folded structure that is critical for its functions. Using the intrinsic fluorescence of Trp(37), we investigated, by the stopped-flow technique, the folding of NCp7 distal finger through the pH dependence of its Zn(2+) association and dissociation kinetics. Zn(2+) binding was found to involve four different paths associated with the four deprotonated states of the finger. Each binding path involves the rapid formation of an intermediate complex that is subsequently rearranged and stabilized in a rate-limiting step. The equilibrium and kinetic rate constants of the full Zn(2+)-binding process have been determined. At neutral pH, the preferential pathway for the Zn(2+)-driven folding implies Zn(2+) binding to the deprotonated Cys(36) and His(44) residues, in the bidentate state of the finger. The resulting intermediate is then converted with a rate constant of 500 s(-1) into a more suitably folded form, probably through a rearrangement of the peptide backbone around Zn(2+) to optimize the binding geometry. This form then rapidly leads to the final native complex, through deprotonation of Cys(39) and Cys(49) residues and intramolecular substitution of coordinated water molecules. Zn(2+) dissociation is also characterized by a multistep process and occurs fastest via the deprotonated Zn(2+)-bound bidentate state with a rate constant of 3 s(-1). Due to their critical role in folding, the intermediates identified for the first time in this study may constitute potential targets for HIV therapy.
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Affiliation(s)
- Elisa Bombarda
- UMR 7175, Centre National de la Recherche Scientifique, Université Louis Pasteur, Faculté de Pharmacie, Illkirch, France.
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15
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Darlix JL, Garrido JL, Morellet N, Mély Y, de Rocquigny H. Properties, functions, and drug targeting of the multifunctional nucleocapsid protein of the human immunodeficiency virus. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2007; 55:299-346. [PMID: 17586319 DOI: 10.1016/s1054-3589(07)55009-x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Jean-Luc Darlix
- LaboRetro, Unité INSERM de Virologie Humaine, IFR128, ENS Sciences de Lyon 46 allée d'Italie, Lyon, France
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16
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Anzellotti AI, Liu Q, Bloemink MJ, Scarsdale JN, Farrell N. Targeting retroviral Zn finger-DNA interactions: a small-molecule approach using the electrophilic nature of trans-platinum-nucleobase compounds. ACTA ACUST UNITED AC 2006; 13:539-48. [PMID: 16720275 DOI: 10.1016/j.chembiol.2006.04.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2006] [Revised: 03/30/2006] [Accepted: 04/03/2006] [Indexed: 11/29/2022]
Abstract
Noncovalent interactions are ubiquitous in ternary systems involving metal ions, DNA/RNA, and proteins and represent a structural motif for design of selective inhibitors of biological function. This contribution shows that small molecules containing platinated purine nucleobases mimic the natural DNA(RNA)-tryptophan recognition interaction of zinc finger peptides, specifically the C-terminal finger of HIV NCp7 protein. Interaction with platinum results in Zn ejection from the peptide accompanied by loss of tertiary structure. Targeting the NCp7-DNA interaction for drug design represents a conceptual advance over electrophiles designed for chemical attack on the zinc finger alone. These results demonstrate examples of a new platinum structural class targeting specific biological processes, distinct from the bifunctional DNA-DNA binding of cytotoxic agents like cisplatin. The results confirm the validity of a chemical biological approach for metallodrug design for selective ternary DNA(RNA)-protein interactions.
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Affiliation(s)
- Atilio I Anzellotti
- Department of Chemistry, Virginia Commonwealth University, PO Box 842006, Richmond, Virginia 23284, USA
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17
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Raja C, Ferner J, Dietrich U, Avilov S, Ficheux D, Darlix JL, de Rocquigny H, Schwalbe H, Mély Y. A Tryptophan-Rich Hexapeptide Inhibits Nucleic Acid Destabilization Chaperoned by the HIV-1 Nucleocapsid Protein. Biochemistry 2006; 45:9254-65. [PMID: 16866372 DOI: 10.1021/bi052560m] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The nucleocapsid protein (NC) of HIV-1 exerts critical functions in viral genome replication and virus assembly. Since the recognition of target nucleic acids is required in the initial step of most NC-mediated processes, attempts were made to find small molecules capable of competing with this recognition. In particular, several Trp-rich hexapeptides were recently found to strongly bind RNA sequences targeted by NC. To further validate these peptides as potential anti-NC agents, we studied the ability of Ac-HKWPWW-NH2, taken as a representative, to interfere with the NC chaperone properties required during reverse transcription. Using NMR and steady-state and time-resolved fluorescence spectroscopy, we characterized the structure of Ac-HKWPWW-NH2 as well as its binding to viral sequences such as TAR and PBS involved in the two obligatory strand transfers of reverse transcription. Results show that Ac-HKWPWW-NH2 exhibits an almost symmetric cis-trans equilibrium at the level of the Pro residue where it is structured. The peptide binds both TAR and PBS sequences with low micromolar affinities. The cis-Pro and trans-Pro conformations of the peptide bind with comparable affinities to (-)PBS, mainly through stacking interactions between the Trp residues and the (-)PBS bases. Though all three Trp residues may contribute to the (-)PBS/Ac-HKWPWW-NH2 complex formation, Trp3 and Trp5 residues are the key residues in the complexes with the cis-Pro and trans-Pro conformations, respectively. Moreover, Ac-HKWPWW-NH2 stabilizes cTAR secondary structure and largely inhibits the NC-directed melting of cTAR. This further strengthens the interest of this peptide for deriving modified peptides capable of inhibiting NC and HIV-1 replication.
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Affiliation(s)
- Chinappan Raja
- Département Pharmacologie et Physicochimie, Faculté de Pharmacie, Institut Gilbert-Laustriat, UMR 7175 CNRS/Université Louis Pasteur (Strasbourg I), 74 route du Rhin, 67401 Illkirch, France
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18
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Fisher RJ, Fivash MJ, Stephen AG, Hagan NA, Shenoy SR, Medaglia MV, Smith LR, Worthy KM, Simpson JT, Shoemaker R, McNitt KL, Johnson DG, Hixson CV, Gorelick RJ, Fabris D, Henderson LE, Rein A. Complex interactions of HIV-1 nucleocapsid protein with oligonucleotides. Nucleic Acids Res 2006; 34:472-84. [PMID: 16434700 PMCID: PMC1351370 DOI: 10.1093/nar/gkj442] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2005] [Revised: 12/23/2005] [Accepted: 12/23/2005] [Indexed: 11/20/2022] Open
Abstract
The HIV-1 nucleocapsid (NC) protein is a small, basic protein containing two retroviral zinc fingers. It is a highly active nucleic acid chaperone; because of this activity, it plays a crucial role in virus replication as a cofactor during reverse transcription, and is probably important in other steps of the replication cycle as well. We previously reported that NC binds with high-affinity to the repeating sequence d(TG)n. We have now analyzed the interaction between NC and d(TG)4 in considerable detail, using surface plasmon resonance (SPR), tryptophan fluorescence quenching (TFQ), fluorescence anisotropy (FA), isothermal titration calorimetry (ITC) and electrospray ionization Fourier transform mass spectrometry (ESI-FTMS). Our results show that the interactions between these two molecules are surprisngly complex: while the K(d) for binding of a single d(TG)4 molecule to NC is only approximately 5 nM in 150 mM NaCl, a single NC molecule is capable of interacting with more than one d(TG)4 molecule, and conversely, more than one NC molecule can bind to a single d(TG)4 molecule. The strengths of these additional binding reactions are quantitated. The implications of this multivalency for the functions of NC in virus replication are discussed.
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Affiliation(s)
- Robert J Fisher
- Protein Chemistry Laboratory, SAIC-Frederick, Inc. NCI Frederick, Frederick, MD 21702, USA.
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19
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Levin JG, Guo J, Rouzina I, Musier-Forsyth K. Nucleic acid chaperone activity of HIV-1 nucleocapsid protein: critical role in reverse transcription and molecular mechanism. ACTA ACUST UNITED AC 2006; 80:217-86. [PMID: 16164976 DOI: 10.1016/s0079-6603(05)80006-6] [Citation(s) in RCA: 286] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Judith G Levin
- Laboratory of Molecular Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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20
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Beltz H, Clauss C, Piémont E, Ficheux D, Gorelick RJ, Roques B, Gabus C, Darlix JL, de Rocquigny H, Mély Y. Structural determinants of HIV-1 nucleocapsid protein for cTAR DNA binding and destabilization, and correlation with inhibition of self-primed DNA synthesis. J Mol Biol 2005; 348:1113-26. [PMID: 15854648 DOI: 10.1016/j.jmb.2005.02.042] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2005] [Revised: 02/17/2005] [Accepted: 02/17/2005] [Indexed: 11/30/2022]
Abstract
The nucleocapsid protein (NC) of human immunodeficiency virus type 1 (HIV-1) is formed of two highly conserved CCHC zinc fingers flanked by small basic domains. NC is required for the two obligatory strand transfers in viral DNA synthesis through its nucleic acid chaperoning properties. The first DNA strand transfer relies on NC's ability to bind and destabilize the secondary structure of complementary transactivation response region (cTAR) DNA, to inhibit self-priming, and to promote the annealing of cTAR to TAR RNA. To further investigate NC chaperone properties, our aim was to identify by fluorescence spectroscopy and gel electrophoresis, the NC structural determinants for cTAR binding and destabilization, and for the inhibition of self-primed DNA synthesis on a model system using a series of NC mutants and HIV-1 reverse transcriptase. NC destabilization and self-priming inhibition properties were found to be supported by the two fingers in their proper context and the basic (29)RAPRKKG(35) linker. The strict requirement of the native proximal finger suggests that its hydrophobic platform (Val13, Phe16, Thr24 and Ala25) is crucial for binding, destabilization and inhibition of self-priming. In contrast, only partial folding of the distal finger is required, probably for presenting the Trp37 residue in an appropriate orientation. Also, Trp37 and the hydrophobic residues of the proximal finger appear to be essential for the propagation of the melting from the cTAR ends up to the middle of the stem. Finally, both N-terminal and C-terminal basic domains contribute to cTAR binding but not to its destabilization.
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Affiliation(s)
- Hervé Beltz
- Laboratoire de Pharmacologie et Physico-Chimie des Interactions Cellulaires et Moléculaires, UMR 7034 CNRS, Faculté de Pharmacie, Université Louis Pasteur, Strasbourg 1, 74, Route du Rhin, 67401 Illkirch Cedex, France
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21
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Ramboarina S, Druillennec S, Morellet N, Bouaziz S, Roques BP. Target specificity of human immunodeficiency virus type 1 NCp7 requires an intact conformation of its CCHC N-terminal zinc finger. J Virol 2004; 78:6682-7. [PMID: 15163759 PMCID: PMC416507 DOI: 10.1128/jvi.78.12.6682-6687.2004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The modification of zinc-binding residues inside the conserved CCHC motif of human immunodeficiency virus type 1 NCp7, in particular into CCHH, induces a complete loss of infectivity. Since the mutant His28NCp7 has been shown to be devoid of infectivity in vivo, the structure-function relationships of the mutant His28(12-53)NCp7 were investigated by nuclear magnetic resonance and surface plasmonic resonance. Although the Cys28-->His mutation modifies drastically the structure of the core domain (residues 12 to 53) of NCp7, His28(12-53)NCp7 still interacts with a 10-fold-lower affinity to specific nucleic acid targets, such as SL3, a stem-loop critically involved in viral RNA packaging, and without affinity change with the nonspecific, single-stranded nucleic acid poly(T). Moreover, His28(12-53)NCp7 and native (12-53)NCp7 displayed the same affinity with reverse transcriptase, but the natures of the complexes are probably different, accounting for the drastic reduction in the amount of RNA packaged in the mutated virus. We propose a structural model of His28(12-53)NCp7 that provides insights into the NCp7 structural features necessary for target recognition and that shows that the specific native structure of the zinc finger domain is strictly required for the optimal target selectivity of NCp7.
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Affiliation(s)
- S Ramboarina
- Département de Pharmacologie Chimique & Génétique, INSERM U266, CNRS FRE 2463, UFR des Sciences Pharmaceutiques et Biologiques, 75270 Paris Cedex 06, France.
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22
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Stote RH, Kellenberger E, Muller H, Bombarda E, Roques BP, Kieffer B, Mély Y. Structure of the His44 → Ala Single Point Mutant of the Distal Finger Motif of HIV-1 Nucleocapsid Protein: A Combined NMR, Molecular Dynamics Simulation, and Fluorescence Study. Biochemistry 2004; 43:7687-97. [PMID: 15196011 DOI: 10.1021/bi036137u] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The nucleocapsid protein (NCp7) of human immunodeficiency virus type 1 (HIV-1) contains two highly conserved CCHC zinc fingers that strongly bind Zn(2+) through coordination of one His and three Cys residues. It has been suggested that NCp7 function is conformation specific since substitution of any of the zinc coordinating residues in the zinc finger motifs leads to subsequent loss of viral infectivity. To further determine the structural requirements necessary for this specific conformation, we investigated by (1)H 2D NMR and molecular dynamics simulations the structure of the distal finger motif of NCp7 in which the zinc coordinating amino acid, His 44, was substituted by a noncoordinating Ala residue. While the fold of the N-terminal part of this mutated peptide was similar to that of the native peptide, an increased lability and significant conformational changes were observed in the vicinity of the His-to-Ala mutation. Moreover, molecular dynamics simulations suggested a mechanism by which the variant peptide can bind zinc ion even though one zinc-coordinating amino acid was lacking. Using the fluorescence of the naturally occurring Trp37 residue, the binding affinity of the variant peptide to the (TG)(3) model oligonucleotide was found to be decreased by about 2 orders of magnitude with respect with the native peptide. Modeling of the DNA:NCp7 complex using structures of the variant peptide suggests that the residues forming a hydrophobic cleft in the native protein are improperly oriented for efficient DNA binding by the variant peptide.
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Affiliation(s)
- Roland H Stote
- Laboratoire de Chimie Biophysique, ISIS UMR 7006 CNRS, Université Louis Pasteur, 8 allée Gaspard Monge, BP 70028, F-67083 Strasbourg Cedex, France.
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23
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Hargittai MRS, Gorelick RJ, Rouzina I, Musier-Forsyth K. Mechanistic insights into the kinetics of HIV-1 nucleocapsid protein-facilitated tRNA annealing to the primer binding site. J Mol Biol 2004; 337:951-68. [PMID: 15033363 DOI: 10.1016/j.jmb.2004.01.054] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2003] [Revised: 01/30/2004] [Accepted: 01/30/2004] [Indexed: 11/22/2022]
Abstract
HIV-1 reverse transcriptase uses human tRNA(Lys,3) as a primer to initiate reverse transcription. Prior to initiation, the 3' 18 nucleotides of this tRNA are annealed to a complementary sequence on the RNA genome known as the primer binding site (PBS). Here, we show that the HIV-1 nucleocapsid protein (NC) enhances this annealing by approximately five orders of magnitude in vitro, decreasing the transition state enthalpy from approximately 20 kcal mol(-1) for the uncatalyzed reaction to 13 kcal mol(-1) for the NC-catalyzed process. Moreover, the annealing follows second-order kinetics, consistent with the nucleation of the intermolecular duplex being the rate-limiting step. This nucleation is preceded by melting of a small duplex region within the original structure, and is followed by much faster zipping of the rest of the 18 base-pair (bp) duplex. A tRNA mutational analysis shows that destabilization of the tRNA acceptor stem has only a minor effect on the annealing rate. In contrast, addition of bases to the 5' end of tRNA that are complementary to its single-stranded 3' end interferes with duplex nucleation and therefore has a much larger effect on the net reaction rate. Assuming that the apparent transition free energy of the annealing reaction, Delta G(++) is a sum of the melting (Delta G(m)) and nucleation (Delta G(nuc)) free energies, we show that NC affects both Delta G(m) and Delta G(nuc). We estimate that ten to 100-fold of the overall rate enhancement is due to NC-induced destabilization of a 4 bp helix in the PBS, while the additional factor of 10(3)-10(4) rate enhancement is a result of NC-facilitated duplex nucleation. The apparently similar effectiveness of wild-type and SSHS NC, a mutant that lacks the zinc finger structures, in facilitating the tRNA annealing reaction is most likely the result of the mutual cancellation of two factors: SSHS NC is less effective than wild-type NC as a duplex destabilizer, but more effective as a duplex nucleating agent.
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Affiliation(s)
- Michele R S Hargittai
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
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24
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Krishnamoorthy G, Roques B, Darlix JL, Mély Y. DNA condensation by the nucleocapsid protein of HIV-1: a mechanism ensuring DNA protection. Nucleic Acids Res 2003; 31:5425-32. [PMID: 12954779 PMCID: PMC203321 DOI: 10.1093/nar/gkg738] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2003] [Revised: 07/12/2003] [Accepted: 07/28/2003] [Indexed: 11/14/2022] Open
Abstract
The nucleocapsid (NC) protein NCp7 of the immunodeficiency virus type 1 is a small basic protein with two zinc finger motifs. NCp7 has key roles in virus replication and structure, which rely on its interactions with nucleic acids. Although most interactions involve RNAs, binding to the viral DNA is thought to be of importance to achieve protection of the DNA against cellular nucleases and its integration into the host genome. We investigated the interaction of NCp7 with plasmid DNA as a model system. The fluorescence probe YOYO-1 was used as the reporter. Binding of NCp7 to DNA caused DNA condensation, as inferred from the dramatic decrease in YOYO-1 fluorescence. Efficient condensation of DNA required the full length NCp7 with the zinc fingers. The fingerless peptide was less efficient in condensing DNA. Binding of both these NC peptides led to freezing of the segmental dynamics of DNA as revealed by anisotropy decay kinetics of YOYO-1. The truncated peptide NC(12-55) which retains the zinc fingers did not lead to DNA condensation despite its ability to bind and partially freeze the segmental motion of DNA. We propose that the histone-like property of NCp7 leading to DNA condensation contributes to viral DNA stability, in vivo.
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Affiliation(s)
- G Krishnamoorthy
- Laboratoire de Pharmacologie et Physicochimie des interactions cellulaires et moléculaires, UMR 7034 du CNRS, Faculté de Pharmacie, Université Louis Pasteur de Strasbourg, 74 Route du Rhin, 67401 Illkirch, France.
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25
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Heath MJ, Derebail SS, Gorelick RJ, DeStefano JJ. Differing roles of the N- and C-terminal zinc fingers in human immunodeficiency virus nucleocapsid protein-enhanced nucleic acid annealing. J Biol Chem 2003; 278:30755-63. [PMID: 12783894 DOI: 10.1074/jbc.m303819200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The replication process of human immunodeficiency virus requires a number of nucleic acid annealing steps facilitated by the hybridization and helix-destabilizing activities of human immunodeficiency virus nucleocapsid (NC) protein. NC contains two CCHC zinc finger motifs numbered 1 and 2 from the N terminus. The amino acids surrounding the CCHC residues differ between the two zinc fingers. Assays were preformed to investigate the activities of the fingers by determining the effect of mutant and wild-type proteins on annealing of 42-nucleotide RNA and DNA complements. The mutants 1.1 NC and 2.2 NC had duplications of the N- and C-terminal zinc fingers in positions 1 and 2. The mutant 2.1 NC had the native zinc fingers with their positions switched. Annealing assays were completed with unstructured and highly structured oligonucleotide complements. 2.2 NC had a near wild-type level of annealing of unstructured nucleic acids, whereas it was completely unable to stimulate annealing of highly structured nucleic acids. In contrast, 1.1 NC was able to stimulate annealing of both unstructured and structured substrates, but to a lesser degree than the wild-type protein. Results suggest that finger 1 has a greater role in unfolding of strong secondary structures, whereas finger 2 serves an accessory role that leads to a further increase in the rate of annealing.
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Affiliation(s)
- Megan J Heath
- Department of Cell Biology and Molecular Genetics, University of Maryland College Park, College Park, Maryland 20742, USA
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26
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Golinelli MP, Hughes SH. Secondary structure in the nucleic acid affects the rate of HIV-1 nucleocapsid-mediated strand annealing. Biochemistry 2003; 42:8153-62. [PMID: 12846564 DOI: 10.1021/bi027039w] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We studied the effects of human immunodeficiency virus type 1 (HIV-1) nucleocapsid (NC) protein on the kinetics of annealing of nucleic acids using model substrates derived from the 3' end of the HIV-1 minus-strand strong-stop DNA (-sssDNA). We used HIV-1 reverse transcriptase (RT) to monitor the annealing reaction. Using several different DNA primers and acceptor oligonucleotides, we found that the rate of annealing increased with the size of the complementary region of the primer and the acceptor strands and decreased when secondary structures could be formed in either the primer or the acceptor strands. The secondary structure had a larger effect on the rate of annealing if the secondary structure extends to the 3' end of the nucleic acid(s). NC protein reduced the rate of annealing between strands with short homologies. NC had no major effect on the rate of annealing when there were at least 13 bases of complementarity between the primer and the acceptor strands and neither strand could form a stable secondary structure. NC increased the rate of annealing when the primer and/or the acceptor strand could form a secondary structure in the region of complementarity. When two strands were in competition as acceptors in an annealing reaction, the specificity of the annealing was determined by the length of the complementarity between the primer and the acceptor strands, the presence or the absence of secondary structures in the primer and/or the acceptor strand, and the presence or the absence of NC in the reaction. This suggests that NC facilitates strand transfer where the nucleic acids have considerable secondary structure (for example, the first strand transfers for viruses whose genomes have considerable secondary structure at their 3' ends). However, NC also appears to increase the fidelity of recombination by reducing strand transfers between segments that have limited complementarity.
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Affiliation(s)
- Marie-Pierre Golinelli
- HIV Drug Resistance Program, National Cancer Institute at Frederick, P.O. Box B, Frederick, Maryland 21702-1201, USA
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27
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Derebail SS, Heath MJ, DeStefano JJ. Evidence for the differential effects of nucleocapsid protein on strand transfer in various regions of the HIV genome. J Biol Chem 2003; 278:15702-12. [PMID: 12595541 DOI: 10.1074/jbc.m211701200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
An in vitro strand transfer assay that mimicked recombinational events occurring during reverse transcription in HIV-1 was used to assess the role of nucleocapsid protein (NC) in strand transfer. Strand transfer in highly structured nucleic acid species from the U3 3' long terminal repeats, gag-pol frameshift region, and Rev response element were strongly enhanced by NC. In contrast, weakly structured templates from the env and pol-vif regions transferred well without NC and showed lower enhancement. The lack of strong polymerase pause sites in the latter regions demonstrated that non-pause driven mechanisms could also promote transfer. Assays conducted using NC zinc finger mutants supported a differential role for the two fingers in strand transfer with finger 1 (N-terminal) being more important on highly structured RNAs. Overall this report suggests a role for structural intricacies of RNA templates in determining the extent of influence of NC on recombination and illustrates that strand transfer may occur by several different mechanisms depending on the structural nature of the RNA.
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Affiliation(s)
- Suchitra S Derebail
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
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28
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Tisné C, Roques BP, Dardel F. Specific recognition of primer tRNA Lys 3 by HIV-1 nucleocapsid protein: involvement of the zinc fingers and the N-terminal basic extension. Biochimie 2003; 85:557-61. [PMID: 12763315 DOI: 10.1016/s0300-9084(03)00034-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Reverse transcription of HIV-1 viral RNA uses human tRNA(Lys)(3) as a primer. We have previously characterised the structural aspects of the tRNA(Lys)(3) interaction by NMR. In HIV-1 virions, the nucleocapsid protein NCp7 contains two zinc fingers flanked by basic residues. Using NMR, the respective role of the N-terminal residues and the zinc fingers in the interaction with tRNA(Lys)(3)/NCp7 was investigated by studying the tRNA(Lys)(3) and tRNA(Lys)(3)/NCp7 complexes. The N-terminal basic residues do not change the footprint of NC on tRNA(Lys)(3)/Cys(23)NCp7 but strengthen the binding whereas the mutation of the zinc-binding histidine at position 23 that was shown to result in non-infectious particles prevents the interaction with the first bases of the acceptor stem.
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Affiliation(s)
- Carine Tisné
- Laboratoire de Cristallographie et RMN Biologiques, UMR 8015 CNRS, Faculté de Pharmacie, 4, avenue de l'Observatoire, 75006 Paris, France.
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29
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Azoulay J, Clamme JP, Darlix JL, Roques BP, Mély Y. Destabilization of the HIV-1 complementary sequence of TAR by the nucleocapsid protein through activation of conformational fluctuations. J Mol Biol 2003; 326:691-700. [PMID: 12581633 DOI: 10.1016/s0022-2836(02)01430-4] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The nucleocapsid protein NCp7 of HIV-1 possesses nucleic acid chaperone properties that are critical for the two obligatory strand transfer reactions required for the synthesis of a complete proviral DNA by reverse transcriptase. The first DNA strand transfer relies on the destabilization by NCp7 of double-stranded segments of the transactivation response region (TAR) sequence at the 3' end of the genomic RNA and the complementary sequence cTAR at the 3' terminus of minus strong-stop DNA, the early product of reverse transcription. In order to determine the dynamics of NCp7-mediated nucleic acid destabilization, we investigated by time-resolved fluorescence spectroscopy and two photon fluorescence correlation spectroscopy, the interaction of a doubly labeled cTAR sequence with NC(12-55) containing NCp7 CCHC zinc fingers and flanking basic amino acid residues. From the chemical rates and the activation energy associated with the conformational fluctuations observed in the absence of NC, it is concluded that such fluctuations are associated with the opening and closing of the double-stranded terminal segments of cTAR. The destabilizing activity of NC(12-55) occurs mainly through a major increase of the opening rate constant of cTAR. Moreover, NC appears to augment the number of pathways between the open and closed states of cTAR, suggesting that it initiates melting of base-pairs at different locations within the terminal segments of cTAR. This activity of NC on the dynamics of cTAR secondary structure is thought to be critical for the formation of the cTAR-TAR complex, which is essential for the specificity and extent of proviral DNA synthesis by reverse transcriptase.
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Affiliation(s)
- Joel Azoulay
- Laboratoire de Pharmacologie et Physico-Chimie des Interactions Cellulaires et Moléculaires, UMR 7034 CNRS, Faculté de Pharmacie, 74, Route du Rhin, 67401 Illkirch, France
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30
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Rist MJ, Marino JP. Mechanism of nucleocapsid protein catalyzed structural isomerization of the dimerization initiation site of HIV-1. Biochemistry 2002; 41:14762-70. [PMID: 12475224 DOI: 10.1021/bi0267240] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dimerization of two homologous strands of genomic RNA is an essential feature of retroviral replication. In the human immunodeficiency virus type 1 (HIV-1), a conserved stem-loop sequence, the dimerization initiation site (DIS), has been identified as the domain primarily responsible for initiation of this aspect of viral assembly. The DIS loop contains an autocomplementary hexanucleotide sequence flanked by highly conserved 5' and 3' purines and can form a homodimer through a loop-loop kissing interaction. In a structural rearrangement activated by the HIV-1 nucleocapsid protein (NCp7) and considered to be associated with viral particle maturation, the DIS dimer converts from an intermediate kissing to an extended duplex isoform. Using 2-aminopurine (2-AP) labeled sequences derived from the DIS(Mal) variant and fluorescence methods, the two DIS dimer isoforms have been unambiguously distinguished, allowing a detailed examination of the kinetics of this RNA structural isomerization and a characterization of the role of NCp7 in the reaction. In the presence of divalent cations, the DIS kissing dimer is found to be kinetically trapped and converts to the extended duplex isoform only upon addition of NCp7. NCp7 is demonstrated to act catalytically in inducing the structural isomerization by accelerating the rate of strand exchange between the two hairpin stem helices, without disruption of the loop-loop helix. Observation of an apparent maximum conversion rate for NCp7-activated DIS isomerization, however, requires protein concentrations in excess of the 2:1 stoichiometry estimated for high-affinity NCp7 binding to the DIS kissing dimer, indicating that transient interactions with additional NCp7(s) may be required for catalysis.
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Affiliation(s)
- Manuela J Rist
- Center for Advanced Research in Biotechnology of the University of Maryland, Rockville 20850, USA
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31
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Zhang WH, Hwang CK, Hu WS, Gorelick RJ, Pathak VK. Zinc finger domain of murine leukemia virus nucleocapsid protein enhances the rate of viral DNA synthesis in vivo. J Virol 2002; 76:7473-84. [PMID: 12097560 PMCID: PMC136396 DOI: 10.1128/jvi.76.15.7473-7484.2002] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In vitro studies have indicated that retroviral nucleocapsid (NC) protein facilitates both DNA synthesis by reverse transcriptase (RT) and annealing of the nascent DNA with acceptor template. Increasing the rate of DNA synthesis is expected to reduce the frequency of RT template switching, whereas annealing the nascent DNA with acceptor template promotes template switching. We performed a mutational analysis of the murine leukemia virus (MLV) NC zinc finger domain to study its effect on RT template switching in vivo and to explore the role of NC during reverse transcription. The effects of NC mutations on RT template switching were determined by using a previously described in vivo direct-repeat deletion assay. A trans-complementation assay was also developed in which replication-defective NC mutants were rescued by coexpression of replication-defective RT mutants that provided wild-type NC in trans. We found that mutations in the MLV NC zinc finger domain increased the frequency of template switching approximately twofold. When a predicted stem-loop RNA secondary structure was introduced into the template RNA, the template-switching frequency increased 5-fold for wild-type NC and further increased up to an additional 6-fold for NC zinc finger domain mutants, resulting in an overall increase of as much as 30-fold. Thus, wild-type NC increased the efficiency with which RT was able to reverse transcribe through regions of RNA secondary structure that might serve as RT pause sites. These results provide the first in vivo evidence that NC enhances the rate of DNA synthesis by RT in regions of the template possessing stable RNA secondary structure.
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Affiliation(s)
- Wen-Hui Zhang
- HIV Drug Resistance Program, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland 21702, USA
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32
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Takahashi H, Sawa H, Hasegawa H, Sata T, Hall WW, Nagashima K, Kurata T. Reconstitution of cleavage of human immunodeficiency virus type-1 (HIV-1) RNAs. Biochem Biophys Res Commun 2002; 293:1084-91. [PMID: 12051771 DOI: 10.1016/s0006-291x(02)00345-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A human immunodeficiency virus type 1 (HIV-1) particle contains approximately 1200 molecules of gag proteins and two copies of a 9.2-kb genomic RNA which has been reported to be dimerized and rapidly cleaved and to form a complex with a nucleocapsid protein, p7 (NCp7), during viral budding. These suggest that the cleavage can be reconstituted with gag proteins in vitro. Here we show that the p15(gag) coding region of viral RNA is fragmented in viral particles and that in vitro-synthesized RNA transcripts of HIV-1 undergo cleavage which is activated by NCp7 and other factors. Single-stranded oligoribonucleotides were cleaved between C and A or U and A, leaving 2',3'-cyclic phosphate and 5'-hydroxyl termini. These findings might explain the rapid degradation of genomic RNAs in HIV-1 particles.
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Affiliation(s)
- Hidehiro Takahashi
- Department of Pathology, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640, Japan.
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33
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Bombarda E, Cherradi H, Morellet N, Roques BP, Mély Y. Zn(2+) binding properties of single-point mutants of the C-terminal zinc finger of the HIV-1 nucleocapsid protein: evidence of a critical role of cysteine 49 in Zn(2+) dissociation. Biochemistry 2002; 41:4312-20. [PMID: 11914077 DOI: 10.1021/bi015956g] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The two highly conserved Zn(2+) finger motifs of the HIV-1 nucleocapsid protein, NCp7, strongly bind Zn(2+) through coordination of one His and three Cys residues. To further analyze the role of these residues, we investigated the Zn(2+) binding and acid-base properties of four single-point mutants of a short peptide corresponding to the distal finger motif of NCp7. In each mutant, one Zn(2+)-coordinating residue is substituted with a noncoordinating one. Using the spectroscopic properties of Co(2+), we first establish that the four mutants retain their ability to bind a metal cation through a four- or five-coordinate geometry with the vacant ligand position(s) presumably occupied by water molecule(s). Moreover, the pK(a) values of the three Cys residues of the mutant apopeptide where His44 is substituted with Ala are found by (1)H NMR to be similar to those of the native peptide, suggesting that the mutations do not affect the acid-base properties of the Zn(2+)-coordinating residues. The binding of Zn(2+) was monitored by using the fluorescence of Trp37 as an intrinsic probe. At pH 7.5, the apparent Zn(2+) binding constants (between 1.6 x 10(8) and 1.3 x 10(10) M(-)(1)) of the four mutants are strongly reduced compared to those of the native peptide but are similar to those of various host Zn(2+) binding proteins. As a consequence, the loss of viral infectivity following the mutation of one Zn(2+)-coordinating residue in vivo may not be related to the total loss of Zn(2+) binding. The pH dependence of Zn(2+) binding indicates that the coordinating residues bind Zn(2+) stepwise and that the free energy provided by the binding of a given residue may be modulated by the entropic contribution of the residues already bound to Zn(2+). Finally, the pK(a) of Cys49 in the holopeptide is found to be 5.0, a value that is at least 0.7 unit higher than those for the other Zn(2+)-coordinating residues. This implies that Cys49 may act as a switch for Zn(2+) dissociation in the distal finger motif of NCp7, a feature that may contribute to the high susceptibility of Cys49 to electrophilic attack.
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Affiliation(s)
- E Bombarda
- Laboratoire de Pharmacologie et Physico-Chimie des Interactions Cellulaires et Moléculaires, UMR 7034 CNRS, Faculté de Pharmacie, Université Louis Pasteur, Strasbourg 1, 74, Route du Rhin, 67401 Illkirch Cedex, France
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34
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Gao X, Rowley DJ, Gai X, Voytas DF. Ty5 gag mutations increase retrotransposition and suggest a role for hydrogen bonding in the function of the nucleocapsid zinc finger. J Virol 2002; 76:3240-7. [PMID: 11884548 PMCID: PMC136051 DOI: 10.1128/jvi.76.7.3240-3247.2002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The Ty5 retrotransposon of Saccharomyces paradoxus transposes in Saccharomyces cerevisiae at frequencies 1,000-fold lower than do the native Ty1 elements. The low transposition activity of Ty5 could be due to differences in cellular environments between these yeast species or to naturally occurring mutations in Ty5. By screening of a Ty5 mutant library, two single mutants (D252N and Y68C) were each found to increase transposition approximately sixfold. When combined, transposition increased 36-fold, implying that the two mutations act independently. Neither mutation affected Ty5 protein synthesis, processing, cDNA recombination, or target site choice. However, cDNA levels in both single mutants and the double mutant were significantly higher than in the wild type. The D252N mutation resides in the zinc finger of nucleocapsid and increases the potential for hydrogen bonding with nucleic acids. We generated other mutations that increase the hydrogen bonding potential (i.e., D252R and D252K) and found that they similarly increased transposition. This suggests that hydrogen bonding within the zinc finger motif is important for cDNA production and builds upon previous studies implicating basic amino acids flanking the zinc finger as important for zinc finger function. Although NCp zinc fingers differ from the zinc finger motifs of cellular enzymes, the requirement for efficient hydrogen bonding is likely universal.
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Affiliation(s)
- Xiang Gao
- Department of Zoology and Genetics, Iowa State University, Ames, Iowa 50011, USA
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35
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Kameoka M, Morgan M, Binette M, Russell RS, Rong L, Guo X, Mouland A, Kleiman L, Liang C, Wainberg MA. The Tat protein of human immunodeficiency virus type 1 (HIV-1) can promote placement of tRNA primer onto viral RNA and suppress later DNA polymerization in HIV-1 reverse transcription. J Virol 2002; 76:3637-45. [PMID: 11907203 PMCID: PMC136076 DOI: 10.1128/jvi.76.8.3637-3645.2002] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus type-1 Tat has been proposed to play a role in the regulation of reverse transcription. We previously demonstrated that wild-type Tat can augment viral infectivity by suppressing the reverse transcriptase (RT) reaction at late stages of the viral life cycle in order to prevent the premature synthesis of potentially deleterious viral DNA products. Here we have performed a detailed analysis of the cell-free reverse transcription reaction to elucidate the mechanism(s) whereby Tat can affect this process. Our results show that Tat can suppress nonspecific DNA elongation while moderately affecting the specific initiation stage of reverse transcription. In addition, Tat has an RNA-annealing activity and can promote the placement of tRNA onto viral RNA. This points to a functional homology between Tat and the viral nucleocapsid (NC) protein that is known to be directly involved in this process. Experiments using a series of mutant Tat proteins revealed that the cysteine-rich and core domains of Tat are responsible for suppression of DNA elongation, while each of the cysteine-rich, core, and basic domains, as well as a glutamine-rich region in the C-terminal domain, are important for the placement of tRNA onto the viral RNA genome. These results suggest that Tat can play at least two different roles in the RT reaction, i.e., suppression of DNA polymerization and placement of tRNA onto viral RNA. We believe that the first of these activities of Tat may contribute to the overall efficiency of reverse transcription of the viral genome during a new round of infection as well as to enhanced production of infectious viral particles. We hypothesize that the second activity, illustrating functional homology between Tat and NC, suggests a potential role for NC in the displacement of Tat during viral maturation.
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Affiliation(s)
- Masanori Kameoka
- McGill University AIDS Centre, Lady Davis Institute-Jewish General Hospital, Montreal, Quebec, Canada H3T 1E2
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36
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Bernacchi S, Stoylov S, Piémont E, Ficheux D, Roques BP, Darlix JL, Mély Y. HIV-1 nucleocapsid protein activates transient melting of least stable parts of the secondary structure of TAR and its complementary sequence. J Mol Biol 2002; 317:385-99. [PMID: 11922672 DOI: 10.1006/jmbi.2002.5429] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The nucleocapsid protein NCp7 of HIV-1 possesses a nucleic acid chaperone activity that is critical in minus and plus strand transfer during reverse transcription. The minus strand transfer notably relies on the ability of NCp7 to destabilize the stable stem with five contiguous, double-stranded segments of both the TAR sequence at the 3' end of the viral genome and the complementary sequence, cTAR, in minus strong-stop DNA. In order to examine the nature and the extent of NCp7 destabilizing activity, we investigated, by absorbance and fluorescence spectroscopy, the interaction of TAR and cTAR with a (12-55)NCp7 peptide containing the zinc-finger motifs but lacking the ability to aggregate the oligonucleotides. The absorbance changes in the UV band of cTAR show that seven to eight base-pairs, on average, are melted per oligonucleotide at a ratio of one peptide to 7.5 nucleotides. In contrast, the melting of TAR does not exceed an average of one base-pair per oligonucleotide. This may be linked to the greater stability of TAR, since a strong correlation between NCp7 destabilizing effect and oligonucleotide stability was observed. The effect of (12-55)NCp7 on the stem terminus was investigated by using a cTAR molecule doubly labeled at the 3' and 5' ends by a donor/acceptor couple. In the absence of the peptide, about 80 % of the oligonucleotides are in a dark non-fluorescent state, having a close proximity of the two dyes. The remaining 20 % are distributed between three fluorescent species, having either the terminal segment, the two terminal segments or all segments of the stem melted. This is in line with a fraying mechanism wherein the stem terminus fluctuates rapidly between open and closed states. Addition of (12-55)NCp7 shifts the equilibrium toward the open species, suggesting that NC enhances fraying of the stem terminus. Taken together, our data suggest that NCp7 activates the transient opening of base-pairs in the least stable parts of the stem. Also, this activity of NCp7 was found to be dependent on the zinc-finger motifs, since no melting was observed with a fingerless NCp7 peptide.
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MESH Headings
- Base Pairing
- Base Sequence
- Capsid/chemistry
- Capsid/metabolism
- Capsid Proteins
- Crystallography, X-Ray
- Gene Products, gag/chemistry
- Gene Products, gag/metabolism
- HIV Long Terminal Repeat/genetics
- HIV-1/genetics
- Models, Molecular
- Molecular Sequence Data
- Nucleic Acid Conformation
- RNA, Viral/chemistry
- RNA, Viral/genetics
- RNA, Viral/metabolism
- RNA-Binding Proteins/chemistry
- RNA-Binding Proteins/metabolism
- Sequence Alignment
- Spectrometry, Fluorescence
- Spectrophotometry, Ultraviolet
- Structure-Activity Relationship
- Viral Proteins
- Zinc Fingers
- gag Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- Serena Bernacchi
- Laboratoire de Pharmacologie et Physico-Chimie des Interactions Cellulaires et Moléculaires, UMR 7034 CNRS, Faculté de Pharmacie, Université Louis Pasteur, 74, Route du Rhin, Strasbourg 1, 67401, France
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37
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Ramboarina S, Srividya N, Atkinson RA, Morellet N, Roques BP, Lefèvre JF, Mély Y, Kieffer B. Effects of temperature on the dynamic behaviour of the HIV-1 nucleocapsid NCp7 and its DNA complex. J Mol Biol 2002; 316:611-27. [PMID: 11866521 DOI: 10.1006/jmbi.2001.5379] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The nucleocapsid protein NCp7 of human immunodeficiency virus type 1 (HIV-1) contains two highly conserved CCHC zinc fingers and is involved in many crucial steps of the virus life-cycle. A large number of physiological rôles of NCp7 involve its binding to single-stranded nucleic acid chains. Several solution structures of NCp7 and its complex with single-stranded RNA or DNA have been reported. We have investigated the changes in the dynamic behaviour experienced by the (12-53)NCp7 peptide upon DNA binding using (15)N heteronuclear relaxation measurements at 293 K and 308 K, and fluorescence spectroscopy. The relaxation data were interpreted using the reduced spectral density approach, which allowed the high-frequency motion, overall tumbling rates and the conformational exchange contributions to be characterized for various states of the peptide without using a specific motional model. Analysis of the temperature-dependent correlation times derived from both NMR and fluorescence data indicated a co-operative change of the molecular shape of apo (12-53)NCp7 around 303 K, leading to an increased hydrodynamic radius at higher temperatures. The binding of (12-53)NCp7 to a single-stranded d(ACGCC) pentanucleotide DNA led to a reduction of the conformational flexibility that characterized the apo peptide. Translational diffusion experiments as well as rotational correlation times indicated that the (12-53)NCp7/d(ACGCC) complex tumbles as a rigid object. The amplitudes of high-frequency motions were restrained in the complex and the occurrence of conformational exchange was displaced from the second zinc finger to the linker residue Ala30.
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Affiliation(s)
- Stéphanie Ramboarina
- Laboratoire de Génomique Structurale, CNRS UPR 9004 ESBS, Bd Sébastien Brant, Illkirch, France
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38
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Abstract
Recombination is a major source of genetic variability in retroviruses. Each viral particle contains two single-stranded genomic RNAs. Recombination mostly results from a switch in template between these two RNAs during reverse transcription. Here we emphasize the main mechanisms underlying recombination that are emerging from recent advances in biochemical and cell culture techniques. Increasing evidence supporting the involvement of RNA secondary structures now complements the predominant role classically attributed to enzyme pausing during reverse transcription. Finally, the implications of recombination on the dynamics of emergence of genomic aberrations in retroviruses are discussed.
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Affiliation(s)
- M Negroni
- Unité de Regulation Enzymatique des Activités Cellulaires, FRE 2364-CNRS, Paris, France.
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39
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Rong L, Liang C, Hsu M, Guo X, Roques BP, Wainberg MA. HIV-1 nucleocapsid protein and the secondary structure of the binary complex formed between tRNA(Lys.3) and viral RNA template play different roles during initiation of (-) strand DNA reverse transcription. J Biol Chem 2001; 276:47725-32. [PMID: 11602578 DOI: 10.1074/jbc.m105124200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In human immunodeficiency virus type 1 (HIV-1), the tRNA(Lys.3) primer and viral RNA template can form a specific complex that is characterized by extensive inter- and intramolecular interactions. Initiation of reverse transcription from this complex has been shown to be distinguished from subsequent elongation by early pausing events, such as at the +1 and +3 nucleotide positions. One major concern regarding the biological relevance of these results is that most kinetic studies of HIV-1 reverse transcription have been performed using tRNA(Lys.3)-viral (v) RNA complexes that were formed by heat annealing. In contrast, tRNA(Lys.3) in viruses is placed onto the primer binding site by nucleocapsid (NC) sequences of the Gag protein. In this study, we have further characterized the initiation features of reverse transcription in the presence of HIV-1 NC protein. In contrast to results obtained with a heat-annealed tRNA(Lys.3).vRNA complex, we found that polymerization reactions catalyzed by HIV-1 reverse transcriptase did not commonly pause at the +1 nucleotide position when a NC-annealed RNA complex was used, and that this was true regardless whether NC was actually still present during reverse transcription. This activity of NC required both zinc finger motifs, as demonstrated by experiments that employed zinc finger-mutated forms of NC protein (H23C NC and ddNC), supporting the involvement of the zinc fingers in the RNA chaperone activity of NC. However, NC was not able to help reverse transcriptase to escape the +3 pausing event. Mutagenesis of a stem structure within the tRNA(Lys.3). vRNA complex led to disappearance of the +3 pausing event as well as to significantly reduced rates of reverse transcription. Thus, this stem structure is essential for optimal reverse transcription, despite its role in promotion of the +3 pausing event.
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MESH Headings
- Amino Acid Motifs
- Animals
- Base Sequence
- Blotting, Western
- COS Cells
- DNA Primers/pharmacology
- DNA, Viral/chemistry
- DNA, Viral/metabolism
- HIV-1/genetics
- HIV-1/metabolism
- Mutagenesis, Site-Directed
- Mutation
- Nucleic Acid Conformation
- Nucleocapsid Proteins/chemistry
- Plasmids/metabolism
- Protein Binding
- Protein Structure, Secondary
- Protein Structure, Tertiary
- RNA/metabolism
- RNA, Transfer, Lys/chemistry
- RNA, Viral/chemistry
- RNA, Viral/metabolism
- RNA-Directed DNA Polymerase/metabolism
- Transcription, Genetic
- Zinc Fingers
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Affiliation(s)
- L Rong
- McGill AIDS Centre, Lady Davis Institute-Jewish General Hospital, Montreal, Quebec H3T 1E2, Canada
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40
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Hargittai MR, Mangla AT, Gorelick RJ, Musier-Forsyth K. HIV-1 nucleocapsid protein zinc finger structures induce tRNA(Lys,3) structural changes but are not critical for primer/template annealing. J Mol Biol 2001; 312:985-97. [PMID: 11580244 DOI: 10.1006/jmbi.2001.5021] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Retroviral reverse transcriptases use host cellular tRNAs as primers to initiate reverse transcription. In the case of human immunodeficiency virus type 1 (HIV-1), the 3' 18 nucleotides of human tRNA(Lys,3) are annealed to a complementary sequence on the RNA genome known as the primer binding site (PBS). The HIV-1 nucleocapsid protein (NC) facilitates this annealing. To understand the structural changes that are induced upon NC binding to the tRNA alone, we employed a chemical probing method using the lanthanide metal terbium. At low concentrations of NC, the strong terbium cleavage observed in the core region of the tRNA is significantly attenuated. Thus, NC binding first results in disruption of the tRNA's metal binding pockets, including those that stabilize the D-TPsiC tertiary interaction. When NC concentrations approach the amount needed for complete primer/template annealing, NC further destabilizes the tRNA acceptor-TPsiC stem minihelix, as evidenced by increased terbium cleavage in this domain. A mutant form of NC (SSHS NC), which lacks the zinc finger structures, is able to anneal tRNA(Lys,3) efficiently to the PBS, and to destabilize the tRNA tertiary core, albeit less effectively than wild-type NC. This mutant form of NC does not affect cleavage significantly in the helical regions, even when bound at high concentrations. These results, as well as experiments conducted in the presence of polyLys, suggest that in the absence of the zinc finger structures, NC acts as a polycation, neutralizing the highly negative phosphodiester backbone. The presence of an effective multivalent cationic peptide is sufficient for efficient tRNA primer annealing to the PBS.
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Affiliation(s)
- M R Hargittai
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
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41
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Takahashi K, Baba S, Koyanagi Y, Yamamoto N, Takaku H, Kawai G. Two basic regions of NCp7 are sufficient for conformational conversion of HIV-1 dimerization initiation site from kissing-loop dimer to extended-duplex dimer. J Biol Chem 2001; 276:31274-8. [PMID: 11418609 DOI: 10.1074/jbc.m104577200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nucleocapsid (NC) protein possesses nucleotide-annealing activities, which are used in various processes in retroviral life cycle. As conserved characters, the NC proteins have one or two zinc fingers of CX(2)CX(4)HX(4)C motif surrounded by basic amino acid sequences. Requirement of the zinc fingers for the annealing activities of NC protein remains controversial. In this study, we focused the requirement in the process of maturation of dimeric viral RNA. Discrimination between immature and mature dimers of synthetic RNA corresponding to the dimerization initiation site of human immunodeficiency virus type 1 (HIV-1) genomic RNA was performed based on their Mg(2+)-dependent stability in gel electrophoreses and on their distinct signal pattern from NMR analysis of imino protons. Chaperoning activity of the HIV-1 NC protein, NCp7, and its fragments for maturation of dimeric RNA was investigated using these experimental systems. We found that the two basic regions flanking the N-terminal zinc finger of NCp7, which are connected by two glycine residues instead of the zinc finger, were sufficient, although about 10 times the amounts of peptide were needed in comparison with intact NCp7. Further, it was found that the amount of basic residues rather than the amino acid sequence itself is important for the activity. The zinc fingers may involve the binding affinity and/or such a possible specific binding of NCp7 to dimerization initiation site dimer that leads to the maturation reaction.
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Affiliation(s)
- K Takahashi
- Department of Industrial Chemistry, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino-shi, Chiba 275-8588, Japan
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42
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Bombarda E, Morellet N, Cherradi H, Spiess B, Bouaziz S, Grell E, Roques BP, Mély Y. Determination of the pK(a) of the four Zn2+-coordinating residues of the distal finger motif of the HIV-1 nucleocapsid protein: consequences on the binding of Zn2+. J Mol Biol 2001; 310:659-72. [PMID: 11439030 DOI: 10.1006/jmbi.2001.4770] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The nucleocapsid protein NCp7 of human immunodeficiency virus type 1 is characterized by two highly conserved CCHC motifs that bind Zn2+ strongly. To elucidate the striking pH-dependence of the apparent Zn2+-binding constants of these motifs further, we investigated, using 1H NMR, potentiometry and fluorescence spectroscopy, the acid-base properties of the four Zn2+-coordinating residues of (35-50)NCp7, a peptide corresponding to the distal finger motif of NCp7. With the exception of the H(beta2) proton of Cys39, the pH-dependence of the H(beta) proton resonances of the three Cys residues and, the H(delta) and H(epsilon) resonances of His44 in the apopeptide could be fitted adequately with a single pK(a). This suggests that the protonating groups are non-interacting, a feature that was confirmed by a potentiometric titration. The pK(a) of His44, Cys36, Cys39, and Cys49 in the apopeptide were found to be 6.4, 8.0, 8.8 and 9.3, respectively. Accordingly, the deprotonation is almost sequential and may thus induce a sequential binding of Zn2+ to the four coordinating residues. The high pK(a) of Cys49 is probably related to the negative charge of the neighboring Asp48. Such a high pK(a) may be a general feature in nucleocapsid proteins (NCs), since an acidic residue generally occupies the (i-1) position of the C-terminal Cys residue of single-finger NCs and distal finger motifs in two-finger NCs. Molecular dynamics simulation suggested the formation of a hydrogen bonded network that weakly structured the Cys36-Cys39 segment in the apopeptide. This network depends on the protonation state of Cys36 and may thus explain the biphasic behavior of the pH-dependence of the Cys39 H(beta2) resonance. Finally, the pK(a) values were used to build up a model describing the coordination of Zn2+ to (35-50)NCp7 at equilibrium. It appears that each protonation step of the coordination complex decreases the Zn2+-binding constant by about four orders of magnitude and that a significant dissociation of Zn2+ from the holopeptide can be achieved in acidic cell compartments.
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Affiliation(s)
- E Bombarda
- Laboratoire de Pharmacologie et Physico-Chimie des Interactions Cellulaires et Moléculaires, UMR 7034 CNRS, Faculté de Pharmacie, Université Louis Pasteur, Strasbourg 1, 74, Route du Rhin, Illkirch Cedex, 67401, France
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43
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Hansen AC, Grunwald T, Lund AH, Schmitz A, Duch M, Uberla K, Pedersen FS. Transfer of primer binding site-mutated simian immunodeficiency virus vectors by genetically engineered artificial and hybrid tRNA-like primers. J Virol 2001; 75:4922-8. [PMID: 11312366 PMCID: PMC114249 DOI: 10.1128/jvi.75.10.4922-4928.2001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Simian immunodeficiency viruses (SIV) harbor primer binding sites (PBS) matching tRNA or tRNA. To study determinants of primer usage in SIV, a SIVmac239-based vector was impaired by mutating the PBS to a sequence (PBS-X2) with no match to any tRNA. By cotransfection of a synthetic gene encoding a tRNA(Pro)-like RNA with a match to PBS-X2, the activity of this vector could be restored to a transduction efficiency slightly lower than that of the wild-type vector. A vector with a PBS matching tRNA(Pro) was functional at a level slightly below that of the wild-type vector, but higher transduction efficiency could be obtained by cotransfection of a gene for an engineered tRNA(Pro)-tRNA hybrid with a match to PBS-Pro. The importance of tRNA backbone identity was further analyzed by complementing the PBS-X2 vector with a gene for a matching x2 primer with a tRNA backbone, which led to three- to fourfold-higher titers than those observed for the x2 primer with the tRNA(Pro) backbone. In summary, our results demonstrate flexibility in PBS and primer usage for SIVmac239, with PBS-primer complementarity being the major determinant, in analogy with previous findings for murine leukemia viruses and human immunodeficiency virus type 1.
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Affiliation(s)
- A C Hansen
- Department of Molecular and Structural Biology, Aarhus University, DK-8000 Aarhus, Denmark
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44
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Gonsky J, Bacharach E, Goff SP. Identification of residues of the Moloney murine leukemia virus nucleocapsid critical for viral DNA synthesis in vivo. J Virol 2001; 75:2616-26. [PMID: 11222684 PMCID: PMC115885 DOI: 10.1128/jvi.75.6.2616-2626.2001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The nucleocapsid (NC) protein of retroviruses is a small nucleic acid-binding protein important in virion assembly and in the encapsidation of the viral RNA genome into the virion particle. Multiple single-amino-acid substitutions were introduced into the NC of Moloney murine leukemia virus to examine further its role in viral replication. Two residues were shown to play important roles in the early events of replication. Unlike viruses with previously characterized NC mutations, these viruses showed no impairment in the late events of replication. Viruses containing the substitutions L21A and K30A expressed the normal complement of properly processed viral Gag proteins. Analysis of the RNA content of mutant virions revealed normal levels of unspliced and spliced viral RNA, and the tRNA(Pro) primer was properly annealed to the primer binding site on the viral genome. The virions demonstrated no defect in initiation of reverse transcription using the endogenous tRNA primer or in the synthesis of long viral DNA products in vitro. Nonetheless, viruses possessing these NC mutations demonstrated significant defects in the synthesis and accumulation of viral DNA products in vivo.
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Affiliation(s)
- J Gonsky
- Integrated Program in Cellular, Molecular, and Biophysical Studies, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA
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45
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Laughrea M, Shen N, Jetté L, Darlix JL, Kleiman L, Wainberg MA. Role of distal zinc finger of nucleocapsid protein in genomic RNA dimerization of human immunodeficiency virus type 1; no role for the palindrome crowning the R-U5 hairpin. Virology 2001; 281:109-16. [PMID: 11222101 DOI: 10.1006/viro.2000.0778] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Genomic RNA isolated from HIV-1 variously mutated in nucleocapsid protein (NC) was characterized by nondenaturing gel electrophoresis. Mutations in the C-terminal, the N-terminal, and the linker regions had no effect on genomic RNA dimerization [they are R7R10K11S, P31L, R32G, S3(32-34), and K59L], while a C36S/C39S mutation in the distal zinc knuckle (Cys-His box or zinc finger) inhibited genome dimerization as much as disrupting the kissing-loop domain. The four mutations which inhibited tRNA(Lys3) genomic placement (i.e., the in vivo placement of tRNA(Lys3) on the primer binding site) had no effect on genome dimerization. Among five mutations which inhibited genome packaging, four had no effect on genome dimerization. Thus the N-terminal and linker regions of NC control genome packaging/tRNA(Lys3) placement (two processes which do not require mature NC) but have little influence on genome dimerization and 2-base extension of tRNA(Lys3) (two processes which are likely to require mature NC). It has been suggested, based on electron microscopy, that the AAGCUU82 palindrome crowning the R-U5 hairpin stimulates genomic RNA dimerization. To test this hypothesis, we deleted AGCU81 from wild-type viruses and from viruses bearing a disrupted kissing-loop hairpin or kissing-loop domain; in another mutant, we duplicated AGCU81. The loss of AGCU81 reduced dimerization by 2.5 +/- 4%; its duplication increased it by 3 +/- 6%. Dissociation temperature was left unchanged. We reach two conclusions. First, the palindrome crowning the R-U5 hairpin has no impact on HIV-1 genome dimerization. Second, genomic RNA dimerization is differentially influenced by NC sequence: it is Zn finger dependent but independent of the basic nature of the N-terminal and linker subdomains. We propose that the NC regions implicated in 2-base extension of tRNA(Lys3) are required for a second (maturation) step of tRNA placement. Genome dimerization and mature tRNA placement would then become two RNA-RNA interactions sharing similar NC sequence requirements.
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Affiliation(s)
- M Laughrea
- McGill AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montreal, Quebec, H3T 1E2, Canada.
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46
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Tisné C, Roques BP, Dardel F. Heteronuclear NMR studies of the interaction of tRNA(Lys)3 with HIV-1 nucleocapsid protein. J Mol Biol 2001; 306:443-54. [PMID: 11178904 DOI: 10.1006/jmbi.2000.4391] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reverse transcription of HIV-1 viral RNA uses human tRNA(Lys)3 as a primer. Recombinant tRNA(Lys)3 was previously overexpressed in Escherichia coli, 15N-labelled and purified for NMR studies. It was shown to be functional for priming of HIV-1 reverse transcription. Using heteronuclear 2D and 3D NMR, we have been able to assign almost all the imino groups in the helical regions and involved in the tertiary base interactions of tRNA(Lys)3. This crucial step enabled us to address the question of the annealing mechanism of tRNA(Lys)3 by the nucleocapsid protein (NC) using heteronuclear NMR. Moreover, structural aspects of the tRNA(Lys)3/(12-53)NCp7 interaction have been characterised. The (12-53)NCp7 protein binds preferentially to the inside of the L-shape of the tRNA(Lys)3, on the acceptor and D stems, and at the level of the tertiary interactions between the D and T-psi-C loops. (12-53)NCp7 binding does not induce the melting of any single base-pair or unwinding of the tRNA(Lys)3 helical domains. Moreover, NMR provides a unique means to investigate the base-pairs that are destabilised by (12-53)NCp7 binding. Indeed, the measurements of the longitudinal relaxation time T1 and of the exchange time of the imino protons revealed two major regions sensitive to catalysis by the protein, namely the G6-U67 and T54(A58) pairs. It is interesting that for the biological role of the NC protein, these pairs could be the starting points of the tRNA melting required for the hybridisation to the viral RNA.
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MESH Headings
- Anticodon/chemistry
- Anticodon/genetics
- Anticodon/metabolism
- Base Pairing
- Base Sequence
- Capsid/chemistry
- Capsid/metabolism
- Capsid Proteins
- Gene Products, gag/chemistry
- Gene Products, gag/metabolism
- HIV-1
- Humans
- Kinetics
- Models, Molecular
- Molecular Sequence Data
- Nitrogen/metabolism
- Nuclear Magnetic Resonance, Biomolecular
- Nucleic Acid Conformation
- Nucleic Acid Denaturation
- Peptide Fragments/chemistry
- Peptide Fragments/metabolism
- Protein Binding
- Protons
- RNA, Transfer, Lys/chemistry
- RNA, Transfer, Lys/genetics
- RNA, Transfer, Lys/metabolism
- Viral Proteins
- gag Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- C Tisné
- Laboratoire de Cristallographie et RMN Biologiques, EP 2075 CNRS Faculté de Pharmacie, 4 avenue de l'Observatoire, Paris, 75006, France.
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47
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Guo J, Wu T, Anderson J, Kane BF, Johnson DG, Gorelick RJ, Henderson LE, Levin JG. Zinc finger structures in the human immunodeficiency virus type 1 nucleocapsid protein facilitate efficient minus- and plus-strand transfer. J Virol 2000; 74:8980-8. [PMID: 10982342 PMCID: PMC102094 DOI: 10.1128/jvi.74.19.8980-8988.2000] [Citation(s) in RCA: 162] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The nucleocapsid protein (NC) of human immunodeficiency virus type 1 (HIV-1) has two zinc fingers, each containing the invariant metal ion binding residues CCHC. Recent reports indicate that mutations in the CCHC motifs are deleterious for reverse transcription in vivo. To identify reverse transcriptase (RT) reactions affected by such changes, we have probed zinc finger functions in NC-dependent RT-catalyzed HIV-1 minus- and plus-strand transfer model systems. Our approach was to examine the activities of wild-type NC and a mutant in which all six cysteine residues were replaced by serine (SSHS NC); this mutation severely disrupts zinc coordination. We find that the zinc fingers contribute to the role of NC in complete tRNA primer removal from minus-strand DNA during plus-strand transfer. Annealing of the primer binding site sequences in plus-strand strong-stop DNA [(+) SSDNA] to its complement in minus-strand acceptor DNA is not dependent on NC zinc fingers. In contrast, the rate of annealing of the complementary R regions in (-) SSDNA and 3' viral RNA during minus-strand transfer is approximately eightfold lower when SSHS NC is used in place of wild-type NC. Moreover, unlike wild-type NC, SSHS NC has only a small stimulatory effect on minus-strand transfer and is essentially unable to block TAR-induced self-priming from (-) SSDNA. Our results strongly suggest that NC zinc finger structures are needed to unfold highly structured RNA and DNA strand transfer intermediates. Thus, it appears that in these cases, zinc finger interactions are important components of NC nucleic acid chaperone activity.
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Affiliation(s)
- J Guo
- Laboratory of Molecular Genetics, National Institute of Child Health and Human Development, Bethesda, Maryland 20892, USA
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48
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De Rocquigny H, Caneparo A, Dong CZ, Delaunay T, Roques BP. Generation of monoclonal antibodies specifically directed against the proximal zinc finger of HIV type 1 NCp7. AIDS Res Hum Retroviruses 2000; 16:1259-67. [PMID: 10957723 DOI: 10.1089/08892220050117023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The HIV-1 NCp7 contains two spatially close zinc fingers, required for the production of infectious particles. To investigate in more detail the function of the zinc finger domain, monoclonal antibodies were generated with a cyclic analog of the NCp7 proximal zinc finger. This analog was shown to bind zinc ions and to preserve the highly folded structure of the native peptide (Dong C-Z et al.: J Am Chem Soc 1995;117:2726-2731). We report here two monoclonal antibodies (2B10 and 4D3), which are the first monoclonal antibodies directed against CCHC NCp7 zinc fingers. Dot-blot experiments revealed that a few nanograms of synthetic NCp7 can be detected on a nitrocellulose membrane. Whereas 2B10 appears specific for an epitope located in sequence 19-27 of NCp7, 4D3 appears to be structurally specific. Immunocomplex affinities were evaluated, using BIAcore technology, to be up to 1 and 10 nM, respectively, for 2B10 and 4D3 in 100 mM NaCl. These antibodies were able to recognize NCp7 in the Gag polyprotein precursor and were shown to immunoprecipitate NCp7 from a cell supernatant. Moreover, NCp7-Vpr interaction mediated by the zinc fingers is inhibited by 2B10, emphasizing the role of these domains in the protein-protein complex. These results indicate that 2B10 and 4D3 behave as useful tools for studying both NC protein functions during the course of virion morphogenesis and the role played by its zinc finger domain at various steps in the retroviral life cycle.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/biosynthesis
- Antibodies, Monoclonal/immunology
- Capsid/chemical synthesis
- Capsid/chemistry
- Capsid/immunology
- Capsid Proteins
- Enzyme-Linked Immunosorbent Assay
- Epitope Mapping
- Female
- Gene Products, gag/chemical synthesis
- Gene Products, gag/chemistry
- Gene Products, gag/immunology
- Gene Products, vpr/immunology
- Humans
- Kinetics
- Mice
- Mice, Inbred BALB C
- Molecular Sequence Data
- Peptides, Cyclic/chemical synthesis
- Peptides, Cyclic/immunology
- Precipitin Tests
- Protein Precursors/immunology
- Surface Plasmon Resonance/methods
- Viral Proteins
- gag Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- H De Rocquigny
- Département de Pharmacochimie Moléculaire et Structurale, INSERM U266-CNRS UMR 8600, UFR des Sciences Pharmaceutiques et Biologiques, Paris, France
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49
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Johnson PE, Turner RB, Wu ZR, Hairston L, Guo J, Levin JG, Summers MF. A mechanism for plus-strand transfer enhancement by the HIV-1 nucleocapsid protein during reverse transcription. Biochemistry 2000; 39:9084-91. [PMID: 10924101 DOI: 10.1021/bi000841i] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The HIV-1 nucleocapsid protein (NC) functions as a nucleic acid chaperone during the plus-strand transfer step in reverse transcription by facilitating annealing of the primer binding site (PBS) sequence in the short plus-strand strong-stop DNA fragment [(+) SSDNA] to a complementary site located near the 3' end of the minus-strand DNA [(-) PBS DNA]. To investigate the mechanism by which NC performs this function, we have prepared an 18-nucleotide (-) PBS DNA for nuclear magnetic resonance (NMR) based structural and NC binding studies. The (-) PBS DNA forms a stable hairpin (T(m) approximately 42 +/- 5 degrees C) that contains a five-residue loop and a bulged thymine in a guanosine-cytosine-rich stem. Addition of substoichiometric amounts of NC results in significant broadening and reductions in NMR signal intensities of the Watson-Crick base-paired imino protons and a reduction by 20 degrees C in the upper temperature at which the imino proton signals are detectable, consistent with destabilization of the structure. The results suggest that inefficient annealing in the absence of NC may be due to the intrinsic stability of an internal (-) PBS DNA hairpin and that NC facilitates strand transfer by destabilizing the hairpin and exposing stem nucleotides for base pairing with the PBS sequence in (+) SSDNA.
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Affiliation(s)
- P E Johnson
- Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 21250, USA
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50
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Negroni M, Buc H. Copy-choice recombination by reverse transcriptases: reshuffling of genetic markers mediated by RNA chaperones. Proc Natl Acad Sci U S A 2000; 97:6385-90. [PMID: 10829081 PMCID: PMC18612 DOI: 10.1073/pnas.120520497] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Copy-choice recombination efficiently reshuffles genetic markers in retroviruses. In vivo, the folding of the genomic RNA is controlled by the nucleocapsid protein (NC). We show that binding of NC onto the acceptor RNA molecule is sufficient to enhance recombination, providing evidence for a mechanism where the structure of the acceptor template determines the template switch. NC as well as another RNA chaperone (StpA) converts recombination into a widespread process no longer restricted to rare hot spots, an effect maximized when both the NC and the reverse transcriptase come from HIV-1. These data suggest that RNA chaperones confer a higher genetic flexibility to retroviruses.
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Affiliation(s)
- M Negroni
- Institut Pasteur, Unité de Physicochimie des Macromolécules Biologiques, Unité de Recherche Associée 1773 du Centre National de la Recherche Scientifique, 75724 Paris cedex 15, France.
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