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Zhao KX, Zhang YY, Wang JS, Wang S, Corona A, Maloccu S, Tramontano E, Pannecouque C, De Clercq E, Meng G, Wang L, Chen FE. Design, synthesis and biological evaluation of Thiazolo[3, 2-a]Pyrimidine derivatives as novel RNase H inhibitors. Bioorg Chem 2024; 148:107495. [PMID: 38805850 DOI: 10.1016/j.bioorg.2024.107495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 05/21/2024] [Accepted: 05/22/2024] [Indexed: 05/30/2024]
Abstract
Targeting Ribonuclease H (RNase H) has been considered a viable strategy for HIV therapy. In this study, a series of novel thiazolo[3, 2-a]pyrimidine derivatives were firstly designed and synthesized as potential inhibitors of HIV-1 RNase H. Among these compounds, A28 exhibited the most potent inhibition against HIV-1 RNase H with an IC50 value of 4.14 μM, which was about 5-fold increase in potency than the hit compound A1 (IC50 = 21.49 μM). To gain deeper insights into the structure-activity relationship (SAR), a CoMFA model was constructed to yield reasonable statistical results (q2 = 0.658 and R2 = 0.969). Results from magnesium ion chelation experiments and molecular docking studies revealed that these thiazolopyrimidine inhibitors may exert their inhibitory activity by binding to an allosteric site on RNase H at the interface between subunits p51 and p66. Furthermore, this analog demonstrated favorable physicochemical properties. Our findings provide valuable groundwork for further development of allosteric inhibitors targeting HIV-1 RNase H.
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Affiliation(s)
- Ke-Xin Zhao
- School of Pharmaceutical Sciences, Henan Key Laboratory of Nanomedicine for Targeting Diagnosis and Treatment, Zhengzhou University, Zhengzhou 450001, China
| | - Yi-Ying Zhang
- Engineering Center of Catalysis and Synthesis for Chiral Molecules, Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Jin-Si Wang
- School of Pharmaceutical Sciences, Henan Key Laboratory of Nanomedicine for Targeting Diagnosis and Treatment, Zhengzhou University, Zhengzhou 450001, China
| | - Shuai Wang
- Engineering Center of Catalysis and Synthesis for Chiral Molecules, Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Angela Corona
- Dept Appl Sci Biosyst, University of Cagliari, I-09042 Monserrato, Italy
| | - Stefania Maloccu
- Dept Appl Sci Biosyst, University of Cagliari, I-09042 Monserrato, Italy
| | - Enzo Tramontano
- Dept Appl Sci Biosyst, University of Cagliari, I-09042 Monserrato, Italy
| | | | - Erik De Clercq
- Rega Institute for Medical Research, KU Leuven, Herestraat 49, B-3000 Leuven, Belgium
| | - Ge Meng
- Engineering Center of Catalysis and Synthesis for Chiral Molecules, Department of Chemistry, Fudan University, Shanghai 200433, China.
| | - Lei Wang
- School of Pharmaceutical Sciences, Henan Key Laboratory of Nanomedicine for Targeting Diagnosis and Treatment, Zhengzhou University, Zhengzhou 450001, China.
| | - Fen-Er Chen
- School of Pharmaceutical Sciences, Henan Key Laboratory of Nanomedicine for Targeting Diagnosis and Treatment, Zhengzhou University, Zhengzhou 450001, China; Engineering Center of Catalysis and Synthesis for Chiral Molecules, Department of Chemistry, Fudan University, Shanghai 200433, China.
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2
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Synthesis and Applications of Nitrogen-Containing Heterocycles as Antiviral Agents. Molecules 2022; 27:molecules27092700. [PMID: 35566055 PMCID: PMC9101374 DOI: 10.3390/molecules27092700] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/10/2022] [Accepted: 04/11/2022] [Indexed: 11/16/2022] Open
Abstract
Viruses have been a long-term source of infectious diseases that can lead to large-scale infections and massive deaths. Especially with the recent highly contagious coronavirus (COVID-19), antiviral drugs were developed nonstop to deal with the emergence of new viruses and subject to drug resistance. Nitrogen-containing heterocycles have compatible structures and properties with exceptional biological activity for the drug design of antiviral agents. They provided a broad spectrum of interference against viral infection at various stages, from blocking early viral entry to disrupting the viral genome replication process by targeting different enzymes and proteins of viruses. This review focused on the synthesis and application of antiviral agents derived from various nitrogen-containing heterocycles, such as indole, pyrrole, pyrimidine, pyrazole, and quinoline, within the last ten years. The synthesized scaffolds target HIV, HCV/HBV, VZV/HSV, SARS-CoV, COVID-19, and influenza viruses.
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3
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Ilina TV, Brosenitsch T, Sluis-Cremer N, Ishima R. Retroviral RNase H: Structure, mechanism, and inhibition. Enzymes 2021; 50:227-247. [PMID: 34861939 DOI: 10.1016/bs.enz.2021.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
All retroviruses encode the enzyme, reverse transcriptase (RT), which is involved in the conversion of the single-stranded viral RNA genome into double-stranded DNA. RT is a multifunctional enzyme and exhibits DNA polymerase and ribonuclease H (RNH) activities, both of which are essential to the reverse-transcription process. Despite the successful development of polymerase-targeting antiviral drugs over the last three decades, no bona fide inhibitor against the RNH activity of HIV-1 RT has progressed to clinical evaluation. In this review article, we describe the retroviral RNH function and inhibition, with primary consideration of the structural aspects of inhibition.
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Affiliation(s)
- Tatiana V Ilina
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Teresa Brosenitsch
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Nicolas Sluis-Cremer
- Department of Medicine, Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Rieko Ishima
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States.
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4
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Fois B, Corona A, Tramontano E, Distinto S, Maccioni E, Meleddu R, Caboni P, Floris C, Cottiglia F. Flavonoids and Acid-Hydrolysis derivatives of Neo-Clerodane diterpenes from Teucrium flavum subsp. glaucum as inhibitors of the HIV-1 reverse transcriptase-associated RNase H function. J Enzyme Inhib Med Chem 2021; 36:749-757. [PMID: 33715562 PMCID: PMC7952052 DOI: 10.1080/14756366.2021.1887170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Bioassay-guided fractionation of the ethyl acetate extract from Teucrium flavum subsp. glaucum, endowed with inhibitory activity towards the HIV-1 reverse transcriptase–associated RNase H function, led to the isolation of salvigenin (1), cirsimaritin (2) and cirsiliol (3) along with the neo-clerodanes teuflavin (4) and teuflavoside (5). Acid hydrolysis of the inactive teuflavoside provided three undescribed neo-clerodanes, flavuglaucins A-C (7-9) and one known neo-clerodane (10). Among all neo-clerodanes, flavuglaucin B showed the highest inhibitory activity towards RNase H function with a IC50 value of 9.1 μM. Molecular modelling and site-directed mutagenesis analysis suggested that flavuglaucin B binds into an allosteric pocket close to RNase H catalytic site. This is the first report of clerodane diterpenoids endowed with anti-reverse transcriptase activity. Neo-clerodanes represent a valid scaffold for the development of a new class of HIV-1 RNase H inhibitors.
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Affiliation(s)
- Benedetta Fois
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, Italy
| | - Angela Corona
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, Italy
| | - Enzo Tramontano
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, Italy.,Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, Monserrato, Italy
| | - Simona Distinto
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, Italy
| | - Elias Maccioni
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, Italy
| | - Rita Meleddu
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, Italy
| | - Pierluigi Caboni
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, Italy
| | - Costantino Floris
- Department of Chemical and Geological Sciences, University of Cagliari, Monserrato, Italy
| | - Filippo Cottiglia
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, Italy
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Corona A, Onnis V, Del Vecchio C, Esposito F, Cheng YC, Tramontano E. 2-(Arylamino)-6-(trifluoromethyl)nicotinic Acid Derivatives: New HIV-1 RT Dual Inhibitors Active on Viral Replication. Molecules 2020; 25:E1338. [PMID: 32183488 PMCID: PMC7144554 DOI: 10.3390/molecules25061338] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 03/11/2020] [Accepted: 03/12/2020] [Indexed: 12/27/2022] Open
Abstract
The persistence of the AIDS epidemic, and the life-long treatment required, indicate the constant need of novel HIV-1 inhibitors. In this scenario the HIV-1 Reverse Transcriptase (RT)-associated ribonuclease H (RNase H) function is a promising drug target. Here we report a series of compounds, developed on the 2-amino-6-(trifluoromethyl)nicotinic acid scaffold, studied as promising RNase H dual inhibitors. Among the 44 tested compounds, 34 inhibited HIV-1 RT-associated RNase H function in the low micromolar range, and seven of them showed also to inhibit viral replication in cell-based assays with a selectivity index up to 10. The most promising compound, 21, inhibited RNase H function with an IC50 of 14 µM and HIV-1 replication in cell-based assays with a selectivity index greater than 10. Mode of action studies revealed that compound 21 is an allosteric dual-site compound inhibiting both HIV-1 RT functions, blocking the polymerase function also in presence of mutations carried by circulating variants resistant to non-nucleoside inhibitors, and the RNase H function interacting with conserved regions within the RNase H domain. Proving compound 21 as a promising lead for the design of new allosteric RNase H inhibitors active against viral replication with not significant cytotoxic effects.
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Affiliation(s)
- Angela Corona
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Cagliari, Italy; (A.C.); (V.O.); (F.E.)
| | - Valentina Onnis
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Cagliari, Italy; (A.C.); (V.O.); (F.E.)
| | - Claudia Del Vecchio
- Department of Molecular Medicine, University of Padova, 35121 Padova, Italy;
| | - Francesca Esposito
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Cagliari, Italy; (A.C.); (V.O.); (F.E.)
| | - Yung-Chi Cheng
- Department of Pharmacology, Yale University Medical School, New Haven, CT 06520-8066, USA;
| | - Enzo Tramontano
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Cagliari, Italy; (A.C.); (V.O.); (F.E.)
- Department of Molecular Medicine, University of Padova, 35121 Padova, Italy;
- Department of Pharmacology, Yale University Medical School, New Haven, CT 06520-8066, USA;
- Genetics and Biomedical Research Institute, National Research Council, 09042 Monserrato, Italy
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6
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1,2,4-Triazolo[1,5- a]pyrimidines as a Novel Class of Inhibitors of the HIV-1 Reverse Transcriptase-Associated Ribonuclease H Activity. Molecules 2020; 25:molecules25051183. [PMID: 32151066 PMCID: PMC7179434 DOI: 10.3390/molecules25051183] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/25/2020] [Accepted: 03/03/2020] [Indexed: 12/27/2022] Open
Abstract
Despite great efforts have been made in the prevention and therapy of human immunodeficiency virus (HIV-1) infection, however the difficulty to eradicate latent viral reservoirs together with the emergence of multi-drug-resistant strains require the search for innovative agents, possibly exploiting novel mechanisms of action. In this context, the HIV-1 reverse transcriptase (RT)-associated ribonuclease H (RNase H), which is one of the few HIV-1 encoded enzymatic function still not targeted by any current drug, can be considered as an appealing target. In this work, we repurposed in-house anti-influenza derivatives based on the 1,2,4-triazolo[1,5-a]-pyrimidine (TZP) scaffold for their ability to inhibit HIV-1 RNase H function. Based on the results, a successive multi-step structural exploration around the TZP core was performed leading to identify catechol derivatives that inhibited RNase H in the low micromolar range without showing RT-associated polymerase inhibitory activity. The antiviral evaluation of the compounds in the MT4 cells showed any activity against HIV-1 (IIIB strain). Molecular modelling and mutagenesis analysis suggested key interactions with an unexplored allosteric site providing insights for the future optimization of this class of RNase H inhibitors.
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7
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Tramontano E, Corona A, Menéndez-Arias L. Ribonuclease H, an unexploited target for antiviral intervention against HIV and hepatitis B virus. Antiviral Res 2019; 171:104613. [PMID: 31550450 DOI: 10.1016/j.antiviral.2019.104613] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 09/18/2019] [Accepted: 09/19/2019] [Indexed: 12/18/2022]
Abstract
Ribonucleases H (RNases H) are endonucleolytic enzymes, evolutionarily related to retroviral integrases, DNA transposases, resolvases and numerous nucleases. RNases H cleave RNA in RNA/DNA hybrids and their activity plays an important role in the replication of prokaryotic and eukaryotic genomes, as well as in the replication of reverse-transcribing viruses. During reverse transcription, the RNase H activity of human immunodeficiency virus (HIV) and hepatitis B virus (HBV) degrades the viral genomic RNA to facilitate the synthesis of viral double-stranded DNA. HIV and HBV reverse transcriptases contain DNA polymerase and RNase H domains that act in a coordinated manner to produce double-stranded viral DNA. Although RNase H inhibitors have not been developed into licensed drugs, recent progress has led to the identification of a number of small molecules with inhibitory activity at low micromolar or even nanomolar concentrations. These compounds can be classified into metal-chelating active site inhibitors and allosteric inhibitors. Among them, α-hydroxytropolones, N-hydroxyisoquinolinediones and N-hydroxypyridinediones represent chemotypes active against both HIV and HBV RNases H. In this review we summarize recent developments in the field including the identification of novel RNase H inhibitors, compounds with dual inhibitory activity, broad specificity and efforts to decrease their toxicity.
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Affiliation(s)
- Enzo Tramontano
- Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy.
| | - Angela Corona
- Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy
| | - Luis Menéndez-Arias
- Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas & Universidad Autónoma de Madrid), Madrid, Spain.
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8
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Oda M, Xi Z, Inaba S, Slack RL, Ishima R. Binding thermodynamics of metal ions to HIV-1 ribonuclease H domain. JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY 2019; 135:2647-2653. [PMID: 30853849 PMCID: PMC6402781 DOI: 10.1007/s10973-018-7445-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/27/2018] [Indexed: 06/09/2023]
Abstract
Metal-protein interactions are not necessarily tight in many transient biological processes, such as cellular signaling, enzyme regulation, and molecular recognition. Here, we analyzed the binding thermodynamics and characterized the structural effect of divalent metal ions, i.e. Mn2+, Zn2+, and Mg2+, to the isolated ribonuclease H (RNH) of human immunodeficiency virus (HIV) using isothermal titration calorimetry (ITC) and circular dichroism. The binding thermodynamics of Mg2+ to RNH was determined using competition ITC experiments, and the binding affinity of Mg2+ was found to be about 40- and 400-times lower than those of Mn2+ and of Zn2+, respectively. The structural analysis showed that Mg2+ binding had little effect on the thermal stability of RNH, while Zn2+ and Mn2+ binding increased the stability. The thermodynamic characteristics of RNH metal binding, compared to intact HIV reverse transcriptase, and a possible mechanism of conformational change induced upon metal ion binding, in correlation with the structure-function relationship, are discussed.
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Affiliation(s)
- Masayuki Oda
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto, Kyoto 606-8522, Japan
| | - Zhaoyong Xi
- Department of Structural Biology, University of Pittsburgh School of, Medicine, Pittsburgh, Pennsylvania 15260, United States
| | - Satomi Inaba
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto, Kyoto 606-8522, Japan
- Research & Utilization Division, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan
| | - Ryan L. Slack
- Department of Structural Biology, University of Pittsburgh School of, Medicine, Pittsburgh, Pennsylvania 15260, United States
| | - Rieko Ishima
- Department of Structural Biology, University of Pittsburgh School of, Medicine, Pittsburgh, Pennsylvania 15260, United States
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9
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Poongavanam V, Corona A, Steinmann C, Scipione L, Grandi N, Pandolfi F, Di Santo R, Costi R, Esposito F, Tramontano E, Kongsted J. Structure-guided approach identifies a novel class of HIV-1 ribonuclease H inhibitors: binding mode insights through magnesium complexation and site-directed mutagenesis studies. MEDCHEMCOMM 2018; 9:562-575. [PMID: 30108947 PMCID: PMC6072344 DOI: 10.1039/c7md00600d] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Accepted: 01/29/2018] [Indexed: 11/21/2022]
Abstract
Persistent HIV infection requires lifelong treatment and among the 2.1 million new HIV infections that occur every year there is an increased rate of transmitted drug-resistant mutations. This fact requires a constant and timely effort in order to identify and develop new HIV inhibitors with innovative mechanisms. The HIV-1 reverse transcriptase (RT) associated ribonuclease H (RNase H) is the only viral encoded enzyme that still lacks an efficient inhibitor despite the fact that it is a well-validated target whose functional abrogation compromises viral infectivity. Identification of new drugs is a long and expensive process that can be speeded up by in silico methods. In the present study, a structure-guided screening is coupled with a similarity-based search on the Specs database to identify a new class of HIV-1 RNase H inhibitors. Out of the 45 compounds selected for experimental testing, 15 inhibited the RNase H function below 100 μM with three hits exhibiting IC50 values <10 μM. The most active compound, AA, inhibits HIV-1 RNase H with an IC50 of 5.1 μM and exhibits a Mg-independent mode of inhibition. Site-directed mutagenesis studies provide valuable insight into the binding mode of newly identified compounds; for instance, compound AA involves extensive interactions with a lipophilic pocket formed by Ala502, Lys503, and Trp (406, 426 and 535) and polar interactions with Arg557 and the highly conserved RNase H primer-grip residue Asn474. The structural insights obtained from this work provide the bases for further lead optimization.
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Affiliation(s)
- Vasanthanathan Poongavanam
- Department of Physics , Chemistry and Pharmacy , University of Southern Denmark , DK-5230 Odense M , Denmark . ;
| | - Angela Corona
- Department of Life and Environmental Sciences , University of Cagliari , Italy .
| | - Casper Steinmann
- Department of Physics , Chemistry and Pharmacy , University of Southern Denmark , DK-5230 Odense M , Denmark . ;
| | - Luigi Scipione
- Dipartimento di Chimica e Tecnologie del Farmaco , Istituto Pasteur-Fondazione Cenci Bolognetti , "Sapienza" Università di Roma , Roma , Italy
| | - Nicole Grandi
- Department of Life and Environmental Sciences , University of Cagliari , Italy .
| | - Fabiana Pandolfi
- Dipartimento di Chimica e Tecnologie del Farmaco , Istituto Pasteur-Fondazione Cenci Bolognetti , "Sapienza" Università di Roma , Roma , Italy
| | - Roberto Di Santo
- Dipartimento di Chimica e Tecnologie del Farmaco , Istituto Pasteur-Fondazione Cenci Bolognetti , "Sapienza" Università di Roma , Roma , Italy
| | - Roberta Costi
- Dipartimento di Chimica e Tecnologie del Farmaco , Istituto Pasteur-Fondazione Cenci Bolognetti , "Sapienza" Università di Roma , Roma , Italy
| | - Francesca Esposito
- Department of Life and Environmental Sciences , University of Cagliari , Italy .
| | - Enzo Tramontano
- Department of Life and Environmental Sciences , University of Cagliari , Italy .
- Istituto di Ricerca Genetica e Biomedica , Consiglio Nazionale delle Ricerche (CNR) , Monserrato(CA) , Italy
| | - Jacob Kongsted
- Department of Physics , Chemistry and Pharmacy , University of Southern Denmark , DK-5230 Odense M , Denmark . ;
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10
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Identification of drivers for the metamorphic transition of HIV-1 reverse transcriptase. Biochem J 2017; 474:3321-3338. [PMID: 28811321 DOI: 10.1042/bcj20170480] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 08/09/2017] [Accepted: 08/15/2017] [Indexed: 11/17/2022]
Abstract
Recent structural characterizations of the p51 and p66 monomers have established an important starting point for understanding the maturation pathway of the human immunodeficiency virus (HIV)-1 reverse transcriptase p66/p51 heterodimer. This process requires a metamorphic transition of the polymerase domain leading to formation of a p66/p66' homodimer that exists as a structural heterodimer. To better understand the drivers for this metamorphic transition, we have performed NMR studies of 15N-labeled RT216 - a construct that includes the fingers and most of the palm domains. These studies are consistent with the conclusion that the p66 monomer exists as a spring-loaded complex. Initial dissociation of the fingers/palm : connection complex allows the fingers/palm to adopt an alternate, more stable structure, reducing the rate of reassociation and facilitating subsequent maturation steps. One of the drivers for an initial extension of the fingers/palm domains is identified as a straightening of helix E relative to its conformation in the monomer by eliminating a bend of ∼50° near residue Phe160. NMR and circular dichroism data also are consistent with the conclusion that a hydrophobic surface of palm domain that becomes exposed after the initial dissociation, as well as the intrinsic conformational preferences of the palm domain C-terminal segment, facilitates the formation of the β-sheet structure that is unique to the active polymerase subunit. Spectral comparisons based on 15N-labeled constructs are all consistent with previous structural conclusions based on studies of 13C-methyl-labeled constructs.
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11
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Preclinical Characterization of PC786, an Inhaled Small-Molecule Respiratory Syncytial Virus L Protein Polymerase Inhibitor. Antimicrob Agents Chemother 2017; 61:AAC.00737-17. [PMID: 28652242 PMCID: PMC5571287 DOI: 10.1128/aac.00737-17] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 06/15/2017] [Indexed: 12/14/2022] Open
Abstract
Although respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infection in infants and young children, attempts to develop an effective therapy have so far proved unsuccessful. Here we report the preclinical profiles of PC786, a potent nonnucleoside RSV L protein polymerase inhibitor, designed for inhalation treatment of RSV infection. PC786 demonstrated a potent and selective antiviral activity against laboratory-adapted or clinical isolates of RSV-A (50% inhibitory concentration [IC50], <0.09 to 0.71 nM) and RSV-B (IC50, 1.3 to 50.6 nM), which were determined by inhibition of cytopathic effects in HEp-2 cells without causing detectable cytotoxicity. The underlying inhibition of virus replication was confirmed by PCR analysis. The effects of PC786 were largely unaffected by the multiplicity of infection (MOI) and were retained in the face of established RSV replication in a time-of-addition study. Persistent anti-RSV effects of PC786 were also demonstrated in human bronchial epithelial cells. In vivo intranasal once daily dosing with PC786 was able to reduce the virus load to undetectable levels in lung homogenates from RSV-infected mice and cotton rats. Treatment with escalating concentrations identified a dominant mutation in the L protein (Y1631H) in vitro. In addition, PC786 potently inhibited RSV RNA-dependent RNA polymerase (RdRp) activity in a cell-free enzyme assay and minigenome assay in HEp-2 cells (IC50, 2.1 and 0.5 nM, respectively). Thus, PC786 was shown to be a potent anti-RSV agent via inhibition of RdRp activity, making topical treatment with this compound a novel potential therapy for the treatment of human RSV infections.
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12
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Karki I, Christen MT, Spiriti J, Slack RL, Oda M, Kanaori K, Zuckerman DM, Ishima R. Entire-Dataset Analysis of NMR Fast-Exchange Titration Spectra: A Mg 2+ Titration Analysis for HIV-1 Ribonuclease H Domain. J Phys Chem B 2016; 120:12420-12431. [PMID: 27973819 DOI: 10.1021/acs.jpcb.6b08323] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This article communicates our study to elucidate the molecular determinants of weak Mg2+ interaction with the ribonuclease H (RNH) domain of HIV-1 reverse transcriptase in solution. As the interaction is weak (a ligand-dissociation constant >1 mM), nonspecific Mg2+ interaction with the protein or interaction of the protein with other solutes that are present in the buffer solution can confound the observed Mg2+-titration data. To investigate these indirect effects, we monitored changes in the chemical shifts of backbone amides of RNH by recording NMR 1H-15N heteronuclear single-quantum coherence spectra upon titration of Mg2+ into an RNH solution. We performed the titration under three different conditions: (1) in the absence of NaCl, (2) in the presence of 50 mM NaCl, and (3) at a constant 160 mM Cl- concentration. Careful analysis of these three sets of titration data, along with molecular dynamics simulation data of RNH with Na+ and Cl- ions, demonstrates two characteristic phenomena distinct from the specific Mg2+ interaction with the active site: (1) weak interaction of Mg2+, as a salt, with the substrate-handle region of the protein and (2) overall apparent lower Mg2+ affinity in the absence of NaCl compared to that in the presence of 50 mM NaCl. A possible explanation may be that the titrated MgCl2 is consumed as a salt and interacts with RNH in the absence of NaCl. In addition, our data suggest that Na+ increases the kinetic rate of the specific Mg2+ interaction at the active site of RNH. Taken together, our study provides biophysical insight into the mechanism of weak metal interaction on a protein.
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Affiliation(s)
- Ichhuk Karki
- Department of Structural Biology and ‡Department of Computational and Systems Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States.,Graduate School of Life and Environmental Sciences, Kyoto Prefectural University and ⊥Department of Biomolecular Engineering, Kyoto Institute of Technology , Kyoto 606, Japan
| | - Martin T Christen
- Department of Structural Biology and ‡Department of Computational and Systems Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States.,Graduate School of Life and Environmental Sciences, Kyoto Prefectural University and ⊥Department of Biomolecular Engineering, Kyoto Institute of Technology , Kyoto 606, Japan
| | - Justin Spiriti
- Department of Structural Biology and ‡Department of Computational and Systems Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States.,Graduate School of Life and Environmental Sciences, Kyoto Prefectural University and ⊥Department of Biomolecular Engineering, Kyoto Institute of Technology , Kyoto 606, Japan
| | - Ryan L Slack
- Department of Structural Biology and ‡Department of Computational and Systems Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States.,Graduate School of Life and Environmental Sciences, Kyoto Prefectural University and ⊥Department of Biomolecular Engineering, Kyoto Institute of Technology , Kyoto 606, Japan
| | - Masayuki Oda
- Department of Structural Biology and ‡Department of Computational and Systems Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States.,Graduate School of Life and Environmental Sciences, Kyoto Prefectural University and ⊥Department of Biomolecular Engineering, Kyoto Institute of Technology , Kyoto 606, Japan
| | - Kenji Kanaori
- Department of Structural Biology and ‡Department of Computational and Systems Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States.,Graduate School of Life and Environmental Sciences, Kyoto Prefectural University and ⊥Department of Biomolecular Engineering, Kyoto Institute of Technology , Kyoto 606, Japan
| | - Daniel M Zuckerman
- Department of Structural Biology and ‡Department of Computational and Systems Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States.,Graduate School of Life and Environmental Sciences, Kyoto Prefectural University and ⊥Department of Biomolecular Engineering, Kyoto Institute of Technology , Kyoto 606, Japan
| | - Rieko Ishima
- Department of Structural Biology and ‡Department of Computational and Systems Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States.,Graduate School of Life and Environmental Sciences, Kyoto Prefectural University and ⊥Department of Biomolecular Engineering, Kyoto Institute of Technology , Kyoto 606, Japan
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13
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Zhang B, D’Erasmo M, Murelli RP, Gallicchio E. Free Energy-Based Virtual Screening and Optimization of RNase H Inhibitors of HIV-1 Reverse Transcriptase. ACS OMEGA 2016; 1:435-447. [PMID: 27713931 PMCID: PMC5046171 DOI: 10.1021/acsomega.6b00123] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 09/07/2016] [Indexed: 06/06/2023]
Abstract
We report the results of a binding free energy-based virtual screening campaign of a library of 77 α-hydroxytropolone derivatives against the challenging RNase H active site of the reverse transcriptase (RT) enzyme of human immunodeficiency virus-1. Multiple protonation states, rotamer states, and binding modalities of each compound were individually evaluated. The work involved more than 300 individual absolute alchemical binding free energy parallel molecular dynamics calculations and over 1 million CPU hours on national computing clusters and a local campus computational grid. The thermodynamic and structural measures obtained in this work rationalize a series of characteristics of this system useful for guiding future synthetic and biochemical efforts. The free energy model identified key ligand-dependent entropic and conformational reorganization processes difficult to capture using standard docking and scoring approaches. Binding free energy-based optimization of the lead compounds emerging from the virtual screen has yielded four compounds with very favorable binding properties, which will be the subject of further experimental investigations. This work is one of the few reported applications of advanced-binding free energy models to large-scale virtual screening and optimization projects. It further demonstrates that, with suitable algorithms and automation, advanced-binding free energy models can have a useful role in early-stage drug-discovery programs.
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Affiliation(s)
- Baofeng Zhang
- Department
of Chemistry, Brooklyn
College, City University of New York, Brooklyn, New York 11210, United States
| | - Michael
P. D’Erasmo
- Department
of Chemistry, Brooklyn
College, City University of New York, Brooklyn, New York 11210, United States
- Ph.D. Program in Chemistry and Ph.D. Program in
Biochemistry, The Graduate Center of the
City University of New York, New
York, New York 10016, United States
| | - Ryan P. Murelli
- Department
of Chemistry, Brooklyn
College, City University of New York, Brooklyn, New York 11210, United States
- Ph.D. Program in Chemistry and Ph.D. Program in
Biochemistry, The Graduate Center of the
City University of New York, New
York, New York 10016, United States
| | - Emilio Gallicchio
- Department
of Chemistry, Brooklyn
College, City University of New York, Brooklyn, New York 11210, United States
- Ph.D. Program in Chemistry and Ph.D. Program in
Biochemistry, The Graduate Center of the
City University of New York, New
York, New York 10016, United States
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14
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Structural Maturation of HIV-1 Reverse Transcriptase-A Metamorphic Solution to Genomic Instability. Viruses 2016; 8:v8100260. [PMID: 27690082 PMCID: PMC5086598 DOI: 10.3390/v8100260] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 09/12/2016] [Indexed: 12/13/2022] Open
Abstract
Human immunodeficiency virus 1 (HIV-1) reverse transcriptase (RT)—a critical enzyme of the viral life cycle—undergoes a complex maturation process, required so that a pair of p66 precursor proteins can develop conformationally along different pathways, one evolving to form active polymerase and ribonuclease H (RH) domains, while the second forms a non-functional polymerase and a proteolyzed RH domain. These parallel maturation pathways rely on the structural ambiguity of a metamorphic polymerase domain, for which the sequence–structure relationship is not unique. Recent nuclear magnetic resonance (NMR) studies utilizing selective labeling techniques, and structural characterization of the p66 monomer precursor have provided important insights into the details of this maturation pathway, revealing many aspects of the three major steps involved: (1) domain rearrangement; (2) dimerization; and (3) subunit-selective RH domain proteolysis. This review summarizes the major structural changes that occur during the maturation process. We also highlight how mutations, often viewed within the context of the mature RT heterodimer, can exert a major influence on maturation and dimerization. It is further suggested that several steps in the RT maturation pathway may provide attractive targets for drug development.
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15
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Boulton S, Melacini G. Advances in NMR Methods To Map Allosteric Sites: From Models to Translation. Chem Rev 2016; 116:6267-304. [PMID: 27111288 DOI: 10.1021/acs.chemrev.5b00718] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The last five years have witnessed major developments in the understanding of the allosteric phenomenon, broadly defined as coupling between remote molecular sites. Such advances have been driven not only by new theoretical models and pharmacological applications of allostery, but also by progress in the experimental approaches designed to map allosteric sites and transitions. Among these techniques, NMR spectroscopy has played a major role given its unique near-atomic resolution and sensitivity to the dynamics that underlie allosteric couplings. Here, we highlight recent progress in the NMR methods tailored to investigate allostery with the goal of offering an overview of which NMR approaches are best suited for which allosterically relevant questions. The picture of the allosteric "NMR toolbox" is provided starting from one of the simplest models of allostery (i.e., the four-state thermodynamic cycle) and continuing to more complex multistate mechanisms. We also review how such an "NMR toolbox" has assisted the elucidation of the allosteric molecular basis for disease-related mutations and the discovery of novel leads for allosteric drugs. From this overview, it is clear that NMR plays a central role not only in experimentally validating transformative theories of allostery, but also in tapping the full translational potential of allosteric systems.
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Affiliation(s)
- Stephen Boulton
- Department of Chemistry and Chemical Biology Department of Biochemistry and Biomedical Sciences, McMaster University , 1280 Main St. W., Hamilton L8S 4M1, Canada
| | - Giuseppe Melacini
- Department of Chemistry and Chemical Biology Department of Biochemistry and Biomedical Sciences, McMaster University , 1280 Main St. W., Hamilton L8S 4M1, Canada
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16
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Chattopadhyay A, O’Connor CJ, Zhang F, Galvagnion C, Galloway WRJD, Tan YS, Stokes JE, Rahman T, Verma C, Spring DR, Itzhaki LS. Discovery of a small-molecule binder of the oncoprotein gankyrin that modulates gankyrin activity in the cell. Sci Rep 2016; 6:23732. [PMID: 27046077 PMCID: PMC4820706 DOI: 10.1038/srep23732] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 03/04/2016] [Indexed: 01/04/2023] Open
Abstract
Gankyrin is an ankyrin-repeat oncoprotein whose overexpression has been implicated in the development of many cancer types. Elevated gankyrin levels are linked to aberrant cellular events including enhanced degradation of tumour suppressor protein p53, and inhibition of gankyrin activity has therefore been identified as an attractive anticancer strategy. Gankyrin interacts with several partner proteins, and a number of these protein-protein interactions (PPIs) are of relevance to cancer. Thus, molecules that bind the PPI interface of gankyrin and interrupt these interactions are of considerable interest. Herein, we report the discovery of a small molecule termed cjoc42 that is capable of binding to gankyrin. Cell-based experiments demonstrate that cjoc42 can inhibit gankyrin activity in a dose-dependent manner: cjoc42 prevents the decrease in p53 protein levels normally associated with high amounts of gankyrin, and it restores p53-dependent transcription and sensitivity to DNA damage. The results represent the first evidence that gankyrin is a "druggable" target with small molecules.
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Affiliation(s)
| | | | - Fengzhi Zhang
- Department of Chemistry, Lensfield Road, Cambridge CB2 1EW, UK
| | | | | | - Yaw Sing Tan
- Department of Chemistry, Lensfield Road, Cambridge CB2 1EW, UK
- Bioinformatics Institute (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671
| | - Jamie E. Stokes
- Department of Chemistry, Lensfield Road, Cambridge CB2 1EW, UK
| | - Taufiq Rahman
- Department of Pharmacology, Tennis Court Road, Cambridge CB2 1PD, UK
| | - Chandra Verma
- Bioinformatics Institute (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543
| | - David R. Spring
- Department of Chemistry, Lensfield Road, Cambridge CB2 1EW, UK
| | - Laura S. Itzhaki
- Department of Pharmacology, Tennis Court Road, Cambridge CB2 1PD, UK
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17
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Ribonuclease H/DNA Polymerase HIV-1 Reverse Transcriptase Dual Inhibitor: Mechanistic Studies on the Allosteric Mode of Action of Isatin-Based Compound RMNC6. PLoS One 2016; 11:e0147225. [PMID: 26800261 PMCID: PMC4723341 DOI: 10.1371/journal.pone.0147225] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 12/30/2015] [Indexed: 12/11/2022] Open
Abstract
The DNA polymerase and ribonuclease H (RNase H) activities of human immunodeficiency virus type 1 (HIV-1) are needed for the replication of the viral genome and are validated drug targets. However, there are no approved drugs inhibiting RNase H and the efficiency of DNA polymerase inhibitors can be diminished by the presence of drug resistance mutations. In this context, drugs inhibiting both activities could represent a significant advance towards better anti-HIV therapies. We report on the mechanisms of allosteric inhibition of a newly synthesized isatin-based compound designated as RMNC6 that showed IC50 values of 1.4 and 9.8 μM on HIV-1 RT-associated RNase H and polymerase activities, respectively. Blind docking studies predict that RMNC6 could bind two different pockets in the RT: one in the DNA polymerase domain (partially overlapping the non-nucleoside RT inhibitor [NNRTI] binding pocket), and a second one close to the RNase H active site. Enzymatic studies showed that RMNC6 interferes with efavirenz (an approved NNRTI) in its binding to the RT polymerase domain, although NNRTI resistance-associated mutations such as K103N, Y181C and Y188L had a minor impact on RT susceptibility to RMNC6. In addition, despite being naturally resistant to NNRTIs, the polymerase activity of HIV-1 group O RT was efficiently inhibited by RMNC6. The compound was also an inhibitor of the RNase H activity of wild-type HIV-1 group O RT, although we observed a 6.5-fold increase in the IC50 in comparison with the prototypic HIV-1 group M subtype B enzyme. Mutagenesis studies showed that RT RNase H domain residues Asn474 and Tyr501, and in a lesser extent Ala502 and Ala508, are critical for RMNC6 inhibition of the endonuclease activity of the RT, without affecting its DNA polymerization activity. Our results show that RMNC6 acts as a dual inhibitor with allosteric sites in the DNA polymerase and the RNase H domains of HIV-1 RT.
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18
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Zheng X, Pedersen LC, Gabel SA, Mueller GA, DeRose EF, London RE. Unfolding the HIV-1 reverse transcriptase RNase H domain--how to lose a molecular tug-of-war. Nucleic Acids Res 2016; 44:1776-88. [PMID: 26773054 PMCID: PMC4770237 DOI: 10.1093/nar/gkv1538] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 12/24/2015] [Indexed: 11/14/2022] Open
Abstract
Formation of the mature HIV-1 reverse transcriptase (RT) p66/p51 heterodimer requires subunit-specific processing of the p66/p66' homodimer precursor. Since the ribonuclease H (RH) domain contains an occult cleavage site located near its center, cleavage must occur either prior to folding or subsequent to unfolding. Recent NMR studies have identified a slow, subunit-specific RH domain unfolding process proposed to result from a residue tug-of-war between the polymerase and RH domains on the functionally inactive, p66' subunit. Here, we describe a structural comparison of the isolated RH domain with a domain swapped RH dimer that reveals several intrinsically destabilizing characteristics of the isolated domain that facilitate excursions of Tyr427 from its binding pocket and separation of helices B and D. These studies provide independent support for the subunit-selective RH domain unfolding pathway in which instability of the Tyr427 binding pocket facilitates its release followed by domain transfer, acting as a trigger for further RH domain destabilization and subsequent unfolding. As further support for this pathway, NMR studies demonstrate that addition of an RH active site-directed isoquinolone ligand retards the subunit-selective RH' domain unfolding behavior of the p66/p66' homodimer. This study demonstrates the feasibility of directly targeting RT maturation with therapeutics.
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Affiliation(s)
- Xunhai Zheng
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Lars C Pedersen
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Scott A Gabel
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Geoffrey A Mueller
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Eugene F DeRose
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Robert E London
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental health Sciences, NIH, Research Triangle Park, NC 27709, USA
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19
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Slack RL, Spiriti J, Ahn J, Parniak MA, Zuckerman DM, Ishima R. Structural integrity of the ribonuclease H domain in HIV-1 reverse transcriptase. Proteins 2015; 83:1526-38. [PMID: 26061827 DOI: 10.1002/prot.24843] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 05/14/2015] [Accepted: 06/03/2015] [Indexed: 02/06/2023]
Abstract
The mature form of reverse transcriptase (RT) is a heterodimer comprising the intact 66-kDa subunit (p66) and a smaller 51-kDa subunit (p51) that is generated by removal of most of the RNase H (RNH) domain from a p66 subunit by proteolytic cleavage between residues 440 and 441. Viral infectivity is eliminated by mutations such as F440A and E438N in the proteolytic cleavage sequence, while normal processing and virus infectivity are restored by a compensatory mutation, T477A, that is located more than 10 Å away from the processing site. The molecular basis for this compensatory effect has remained unclear. We therefore investigated structural characteristics of RNH mutants using computational and experimental approaches. Our Nuclear Magnetic Resonance and Differential Scanning Fluorimetry results show that both F440A and E438N mutations disrupt RNH folding. Addition of the T477A mutation restores correct folding of the RNH domain despite the presence of the F440A or E438N mutations. Molecular dynamics simulations suggest that the T477A mutation affects the processing site by altering relative orientations of secondary structure elements. Predictions of sequence tolerance suggest that phenylalanine and tyrosine are structurally preferred at residues 440 and 441, respectively, which are the P1 and P1' substrate residues known to require bulky side chains for substrate specificity. Interestingly, our study demonstrates that the processing site residues, which are critical for protease substrate specificity and must be exposed to the solvent for efficient processing, also function to maintain proper RNH folding in the p66/p51 heterodimer.
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Affiliation(s)
- Ryan L Slack
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, 15260
| | - Justin Spiriti
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, 15260
| | - Jinwoo Ahn
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, 15260
| | - Michael A Parniak
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, 15260
| | - Daniel M Zuckerman
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, 15260
| | - Rieko Ishima
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, 15260
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20
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Poongavanam V, Olsen JMH, Kongsted J. Binding free energy based structural dynamics analysis of HIV-1 RT RNase H-inhibitor complexes. Integr Biol (Camb) 2015; 6:1010-22. [PMID: 25119978 DOI: 10.1039/c4ib00111g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Accurate prediction of binding free energies associated with small molecules binding to a receptor is a major challenge in drug design processes. To achieve this goal many computational methods have been developed ranging from highly efficient empirical based docking schemes to high accuracy methods based on e.g. free energy calculations. In this study, binding affinity predictions for a set of HIV-1 RNase H inhibitors have been performed using MM-PB(GB)/SA methods. The current study describes in detail how the choice of initial ligand structures, e.g. protonation states, impacts the predicted ranking of the compounds. In addition we study the structural dynamics of the RNase H complexes using molecular dynamics. The role of each residue contribution to the overall binding free energy is also explored and used to explain the variations in the inhibition potency. The results reported here can be useful for design of small molecules against RNase H activity in the development of effective drugs for HIV treatment.
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Affiliation(s)
- Vasanthanathan Poongavanam
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
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21
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A Combined NMR and Computational Approach to Investigate Peptide Binding to a Designed Armadillo Repeat Protein. J Mol Biol 2015; 427:1916-33. [DOI: 10.1016/j.jmb.2015.02.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 02/18/2015] [Accepted: 02/23/2015] [Indexed: 11/19/2022]
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22
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Enzymatic Activities of RNase H Domains of HIV-1 Reverse Transcriptase with Substrate Binding Domains of Bacterial RNases H1 and H2. Mol Biotechnol 2015; 57:526-38. [DOI: 10.1007/s12033-015-9846-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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23
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Abstract
Solution-state NMR has been widely applied to determine the three-dimensional structure, dynamics, and molecular interactions of proteins. The designs of experiments used in protein NMR differ from those used for small-molecule NMR, primarily because the information available prior to an experiment, such as molecular mass and knowledge of the primary structure, is unique for proteins compared to small molecules. In this review article, protein NMR for structural biology is introduced with comparisons to small-molecule NMR, such as descriptions of labeling strategies and the effects of molecular dynamics on relaxation. Next, applications for protein NMR are reviewed, especially practical aspects for protein-observed ligand-protein interaction studies. Overall, the following topics are described: (1) characteristics of protein NMR, (2) methods to detect protein-ligand interactions by NMR, and (3) practical aspects of carrying out protein-observed inhibitor-protein interaction studies.
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Affiliation(s)
- Rieko Ishima
- Address correspondence to Rieko Ishima: Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Tel: 412-648-9056; Fax: 412-648-9008;
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24
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Jain (Pancholi) N, Gupta S, Sapre N, Sapre NS. In silico de novo design of novel NNRTIs: a bio-molecular modelling approach. RSC Adv 2015. [DOI: 10.1039/c4ra15478a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Six novel NNRTIs (DABO) with high efficacy are designed by assessing the interaction potential and structural requirements using chemometric analyses (SVM, BPNN and MLR) on structural descriptors.
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Affiliation(s)
| | - Swagata Gupta
- Department of Chemistry
- Govt. BLPPG College
- MHOW, India
| | - Neelima Sapre
- Department of Mathematics and Computational Sc
- SGSITS
- Indore, India
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25
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Singh K, Flores JA, Kirby KA, Neogi U, Sonnerborg A, Hachiya A, Das K, Arnold E, McArthur C, Parniak M, Sarafianos SG. Drug resistance in non-B subtype HIV-1: impact of HIV-1 reverse transcriptase inhibitors. Viruses 2014; 6:3535-62. [PMID: 25254383 PMCID: PMC4189038 DOI: 10.3390/v6093535] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 09/09/2014] [Accepted: 09/09/2014] [Indexed: 01/20/2023] Open
Abstract
Human immunodeficiency virus (HIV) causes approximately 2.5 million new infections every year, and nearly 1.6 million patients succumb to HIV each year. Several factors, including cross-species transmission and error-prone replication have resulted in extraordinary genetic diversity of HIV groups. One of these groups, known as group M (main) contains nine subtypes (A-D, F-H and J-K) and causes ~95% of all HIV infections. Most reported data on susceptibility and resistance to anti-HIV therapies are from subtype B HIV infections, which are prevalent in developed countries but account for only ~12% of all global HIV infections, whereas non-B subtype HIV infections that account for ~88% of all HIV infections are prevalent primarily in low and middle-income countries. Although the treatments for subtype B infections are generally effective against non-B subtype infections, there are differences in response to therapies. Here, we review how polymorphisms, transmission efficiency of drug-resistant strains, and differences in genetic barrier for drug resistance can differentially alter the response to reverse transcriptase-targeting therapies in various subtypes.
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Affiliation(s)
- Kamalendra Singh
- Christopher Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.
| | - Jacqueline A Flores
- Christopher Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.
| | - Karen A Kirby
- Christopher Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.
| | - Ujjwal Neogi
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institute, Stockholm 141 86, Sweden.
| | - Anders Sonnerborg
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institute, Stockholm 141 86, Sweden.
| | - Atsuko Hachiya
- Clinical Research Center, Department of Infectious Diseases and Immunology, National Hospital Organization, Nagoya Medical Center, Nagoya 460-0001, Japan.
| | - Kalyan Das
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ 08854, USA.
| | - Eddy Arnold
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ 08854, USA.
| | - Carole McArthur
- Department of Oral and Craniofacial Science , School of Dentistry, University of Missouri, Kansas City, MO 64108, USA.
| | - Michael Parniak
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA.
| | - Stefan G Sarafianos
- Christopher Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.
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26
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Jain Pancholi N, Gupta S, Sapre N, Sapre NS. Design of novel leads: ligand based computational modeling studies on non-nucleoside reverse transcriptase inhibitors (NNRTIs) of HIV-1. MOLECULAR BIOSYSTEMS 2014; 10:313-25. [PMID: 24292893 DOI: 10.1039/c3mb70218a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Researchers are on the constant lookout for new antiviral agents for the treatment of AIDS. In the present work, ligand based modeling studies are performed on analogues of substituted phenyl-thio-thymines, which act as non-nucleoside reverse transcriptase inhibitors (NNRTIs) and novel leads are extracted. Using alignment-dependent descriptors, based on group center overlap (SALL, HDALL, HAALL and RALL), an alignment-independent descriptor (S log P), a topological descriptor (Balaban index (J)) and a 3D descriptor dipole moment (μ) and shape based descriptors (Kappa 2 index ((2)κ)), a correlation is derived with inhibitory activity. Linear and non-linear techniques have been used to achieve the goal. Support Vector Machine (SVM, R = 0.929, R(2) = 0.863) and Back Propagation Neural Network (BPNN, R = 0.928, R(2) = 0.861) methods yielded near similar results and outperformed Multiple Linear Regression (MLR, R = 0.915, R(2) = 0.837). The predictive ability of the models are cross-validated using a test dataset (SVM: R = 0.846, R(2) = 0.716, BPNN: R = 0.841, R(2) = 0.707 and MLR: R = 0.833, R(2) = 0.694). It is concluded that the hydrophobicity (S log P) and the polarity (μ) of a ligand and the presence of hydrogen donor (HDALL) moieties are the deciding factors in improving antiviral activity and pharmaco-therapeutic properties. Based on the above findings, a virtual dataset is created to extract probable leads with reasonable antiviral activity as well as better pharmacophoric properties.
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Affiliation(s)
- Nilanjana Jain Pancholi
- Department of Applied Chemistry, Shri G.S. Institute of Technology and Sciences, Indore, MP 452001, India.
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27
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Active site and allosteric inhibitors of the ribonuclease H activity of HIV reverse transcriptase. Future Med Chem 2014; 5:2127-39. [PMID: 24261890 DOI: 10.4155/fmc.13.178] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Despite the wealth of information available for the reverse transcriptase (RT)-associated ribonuclease H (RNaseH) domain of lentiviruses, gammaretroviruses and long terminal repeat containing retrotransposons, exploiting this information in the form of an RNaseH inhibitor with high specificity and low cellular toxicity has been disappointing. However, it is now becoming increasingly evident that the two-subunit HIV-1 RT is a highly versatile enzyme, undergoing major structural alterations in order to interact with, position and ultimately hydrolyze the RNA component of an RNA/DNA hybrid. Thus, in addition to targeting the RNaseH active site, identifying small molecules that bind elsewhere and disrupt catalysis allosterically by impairing conformational flexibility is gaining increased attention. This review summarizes current progress towards development of both active site and allosteric RNaseH inhibitors.
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28
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Kang D, Song Y, Chen W, Zhan P, Liu X. “Old Dogs with New Tricks”: exploiting alternative mechanisms of action and new drug design strategies for clinically validated HIV targets. MOLECULAR BIOSYSTEMS 2014; 10:1998-2022. [DOI: 10.1039/c4mb00147h] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ilina T, LaBarge K, Sarafianos SG, Ishima R, Parniak MA. Inhibitors of HIV-1 Reverse Transcriptase-Associated Ribonuclease H Activity. BIOLOGY 2014; 1:521-41. [PMID: 23599900 PMCID: PMC3627382 DOI: 10.3390/biology1030521] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
HIV-1 enzyme reverse transcriptase (RT) is a major target for antiviral drug development, with over half of current FDA-approved therapeutics against HIV infection targeting the DNA polymerase activity of this enzyme. HIV-1 RT is a multifunctional enzyme that has RNA and DNA dependent polymerase activity, along with ribonuclease H (RNase H) activity. The latter is responsible for degradation of the viral genomic RNA template during first strand DNA synthesis to allow completion of reverse transcription and the viral dsDNA. While the RNase H activity of RT has been shown to be essential for virus infectivity, all currently used drugs directed at RT inhibit the polymerase activity of the enzyme; none target RNase H. In the last decade, the increasing prevalence of HIV variants resistant to clinically used antiretrovirals has stimulated the search for inhibitors directed at stages of HIV replication different than those targeted by current drugs. HIV RNase H is one such novel target and, over the past few years, significant progress has been made in identifying and characterizing new RNase H inhibitor pharmacophores. In this review we focus mainly on the most potent low micromolar potency compounds, as these provide logical bases for further development. We also discuss why HIV RNase H has been a difficult target for antiretroviral drug development.
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Affiliation(s)
- Tatiana Ilina
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, 450 Technology Drive, S.414, Pittsburgh, PA 15219, USA; (T.I.); (K.L.)
| | - Krystal LaBarge
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, 450 Technology Drive, S.414, Pittsburgh, PA 15219, USA; (T.I.); (K.L.)
- Department of Molecular Microbiology & Immunology, University of Missouri, Columbia, MO, USA;
| | - Stefan G. Sarafianos
- Structural Biology, University of Pittsburgh School of Medicine, 450 Technology Drive, S.414, Pittsburgh, PA 15219, USA;
| | - Rieko Ishima
- Department of Molecular Microbiology & Immunology, University of Missouri, Columbia, MO, USA;
| | - Michael A. Parniak
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, 450 Technology Drive, S.414, Pittsburgh, PA 15219, USA; (T.I.); (K.L.)
- Author to whom correspondence should be addressed; ; Tel.: +1-412-648-1927; Fax: +1-412-648-9653
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Sharaf NG, Poliner E, Slack RL, Christen MT, Byeon IJL, Parniak MA, Gronenborn AM, Ishima R. The p66 immature precursor of HIV-1 reverse transcriptase. Proteins 2014; 82:2343-52. [PMID: 24771554 DOI: 10.1002/prot.24594] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 04/04/2014] [Accepted: 04/22/2014] [Indexed: 01/07/2023]
Abstract
In contrast to the wealth of structural data available for the mature p66/p51 heterodimeric human immunodeficiency virus type 1 reverse transcriptase (RT), the structure of the homodimeric p66 precursor remains unknown. In all X-ray structures of mature RT, free or complexed, the processing site in the p66 subunit, for generating the p51 subunit, is sequestered into a β-strand within the folded ribonuclease H (RNH) domain and is not readily accessible to proteolysis, rendering it difficult to propose a simple and straightforward mechanism of the maturation step. Here, we investigated, by solution NMR, the conformation of the RT p66 homodimer. Our data demonstrate that the RNH and Thumb domains in the p66 homodimer are folded and possess conformations very similar to those in mature RT. This finding suggests that maturation models which invoke a complete or predominantly unfolded RNH domain are unlikely. The present study lays the foundation for further in-depth mechanistic investigations at the atomic level.
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Affiliation(s)
- Naima G Sharaf
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, 15260
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Inhibition of foamy virus reverse transcriptase by human immunodeficiency virus type 1 RNase H inhibitors. Antimicrob Agents Chemother 2014; 58:4086-93. [PMID: 24798282 DOI: 10.1128/aac.00056-14] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
RNase H plays an essential role in the replication of human immunodeficiency virus type 1 (HIV-1). Therefore, it is a promising target for drug development. However, the identification of HIV-1 RNase H inhibitors (RHIs) has been hampered by the open morphology of its active site, the limited number of available RNase H crystal structures in complex with inhibitors, and the fact that, due to the high concentrations of Mg(2+) needed for protein stability, HIV-1 RNase H is not suitable for nuclear magnetic resonance (NMR) inhibitor studies. We recently showed that the RNase H domains of HIV-1 and prototype foamy virus (PFV) reverse transcriptases (RTs) exhibit a high degree of structural similarity. Thus, we examined whether PFV RNase H can serve as an HIV-1 RNase H model for inhibitor interaction studies. Five HIV-1 RHIs inhibited PFV RNase H activity at low-micromolar concentrations similar to those of HIV-1 RNase H, suggesting pocket similarity of the RNase H domains. NMR titration experiments with the PFV RNase H domain and the RHI RDS1643 (6-[1-(4-fluorophenyl)methyl-1H-pyrrol-2-yl)]-2,4-dioxo-5-hexenoic acid ethyl ester) were performed to determine its binding site. Based on these results and previous data, in silico docking analysis showed a putative RDS1643 binding region that reaches into the PFV RNase H active site. Structural overlays were performed with HIV-1 and PFV RNase H to propose the RDS1643 binding site in HIV-1 RNase H. Our results suggest that this approach can be used to establish PFV RNase H as a model system for HIV-1 RNase H in order to identify putative inhibitor binding sites in HIV-1 RNase H.
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Corona A, Esposito F, Tramontano E. Can the ever-promising target HIV reverse transcriptase-associated RNase H become a success story for drug development? Future Virol 2014. [DOI: 10.2217/fvl.14.24] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Angela Corona
- Dept. of Life & Environmental Sciences, University of Cagliari, Cittadella di Monserrato SS554, 09042, Monserrato (Cagliari), Italy
| | - Francesca Esposito
- Dept. of Life & Environmental Sciences, University of Cagliari, Cittadella di Monserrato SS554, 09042, Monserrato (Cagliari), Italy
| | - Enzo Tramontano
- Dept. of Life & Environmental Sciences, University of Cagliari, Cittadella di Monserrato SS554, 09042, Monserrato (Cagliari), Italy
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