1
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Starvaggi J, Previti S, Zappalà M, Ettari R. The Inhibition of NS2B/NS3 Protease: A New Therapeutic Opportunity to Treat Dengue and Zika Virus Infection. Int J Mol Sci 2024; 25:4376. [PMID: 38673962 PMCID: PMC11050111 DOI: 10.3390/ijms25084376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 04/12/2024] [Accepted: 04/14/2024] [Indexed: 04/28/2024] Open
Abstract
In the global pandemic scenario, dengue and zika viruses (DENV and ZIKV, respectively), both mosquito-borne members of the flaviviridae family, represent a serious health problem, and considering the absence of specific antiviral drugs and available vaccines, there is a dire need to identify new targets to treat these types of viral infections. Within this drug discovery process, the protease NS2B/NS3 is considered the primary target for the development of novel anti-flavivirus drugs. The NS2B/NS3 is a serine protease that has a dual function both in the viral replication process and in the elusion of the innate immunity. To date, two main classes of NS2B/NS3 of DENV and ZIKV protease inhibitors have been discovered: those that bind to the orthosteric site and those that act at the allosteric site. Therefore, this perspective article aims to discuss the main features of the use of the most potent NS2B/NS3 inhibitors and their impact at the social level.
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Affiliation(s)
| | | | | | - Roberta Ettari
- Department of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, Viale Ferdinando Stagno d’Alcontres 31, 98166 Messina, Italy; (J.S.); (S.P.); (M.Z.)
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2
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Cruz KG, Eron MH, Makhaik S, Savinov S, Hardy JA. A Non-Active-Site Inhibitor with Selectivity for Zika Virus NS2B-NS3 Protease. ACS Infect Dis 2024; 10:412-425. [PMID: 38265226 PMCID: PMC11099878 DOI: 10.1021/acsinfecdis.3c00330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
Flavivirus infection usually results in fever accompanied by headache, arthralgia, and, in some cases, rash. Although the symptoms are mild, full recovery can take several months. Flaviviruses encode seven nonstructural proteins that represent potential drug targets for this viral family. Focusing on the Zika virus NS2B-NS3 protease, we uncovered a unique inhibitor, MH1, composed of aminothiazolopyridine and benzofuran moieties. MH1 inhibits ZVP with a biochemical IC50 of 440 nM and effectively blocks cleavage of ZVP substrates in cells. Surprisingly, MH1 inhibits the other flaviviral proteases at least 18-fold more weakly. This same phenomenon was observed in assays of the viral cytopathic effect, where only Zika virus showed sensitivity to MH1. This selectivity was unexpected since flaviviral proteases have high similarity in sequence and protein structure. MH1 binds at an allosteric site, as demonstrated by its ability to stabilize ZVP synergistically with an active site inhibitor. To understand its selectivity, we constructed a series of hybrid proteases composed of select segments of ZVP, which is sensitive to MH1, and dengue virus protease, which is essentially insensitive to MH1. Our results suggest that MH1 binds to the NS3 protease domain, disrupting its interaction with NS2B. These interactions are essential for substrate binding and cleavage. In particular, the unique dynamic properties of NS2B from Zika seem to be required for the function of MH1. Insights into the mechanism of MH1 function will aid us in developing non-active-site-directed, pan-flaviviral inhibitors, by highlighting the importance of evaluating and considering the dynamics of the NS2B regions.
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Affiliation(s)
| | | | - Sparsh Makhaik
- Department of Chemistry, University of Massachusetts Amherst, MA, US 01002
| | | | - Jeanne A. Hardy
- Department of Chemistry, University of Massachusetts Amherst, MA, US 01002
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3
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Structural Insights into Plasticity and Discovery of Flavonoid Allosteric Inhibitors of Flavivirus NS2B–NS3 Protease. BIOPHYSICA 2023. [DOI: 10.3390/biophysica3010006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Flaviviruses are among the most critical pathogens in tropical regions; they cause various severe diseases in developing countries but are not restricted to these countries. The development of antiviral therapeutics is crucial for managing flavivirus outbreaks. Ten proteins are encoded in the flavivirus RNA. The N2B–NS3pro protein complex plays a fundamental role in flavivirus replication and is a promising drug target; however, no flavivirus protease inhibitors have progressed to the preclinical stage. This study analyzed the structural models and plasticity of the NS2B–NS3pro protein complex of five medically important non-dengue flaviviruses (West Nile, Rocio, Ilhéus, yellow fever, and Saint Louis encephalitis). The flavonoids amentoflavone, tetrahydrorobustaflavone, and quercetin were selected for their exceptional binding energies as potential inhibitors of the NS2B–NS3pro protein complex. AutoDock Vina results ranged from −7.0 kcal/mol to −11.5 kcal/mol and the compounds preferentially acted non-competitively. Additionally, the first structural model for the NS2B–NS3pro protein complex was proposed for Ilhéus and Rocio viruses. The NS2B–NS3pro protease is an attractive molecular target for drug development. The three identified natural flavonoids showed great inhibitory potential against the viral species. Nevertheless, further in silico and in vitro studies are required to obtain more information regarding NS2B–NS3pro inhibition by these flavonoids and their therapeutic potential.
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4
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Kumar S, Verma A, Yadav P, Dubey SK, Azhar EI, Maitra SS, Dwivedi VD. Molecular pathogenesis of Japanese encephalitis and possible therapeutic strategies. Arch Virol 2022; 167:1739-1762. [PMID: 35654913 PMCID: PMC9162114 DOI: 10.1007/s00705-022-05481-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 03/10/2022] [Indexed: 12/26/2022]
Abstract
Japanese encephalitis virus (JEV), a single-stranded, enveloped RNA virus, is a health concern across Asian countries, associated with severe neurological disorders, especially in children. Primarily, pigs, bats, and birds are the natural hosts for JEV, but humans are infected incidentally. JEV requires a few host proteins for its entry and replication inside the mammalian host cell. The endoplasmic reticulum (ER) plays a significant role in JEV genome replication and assembly. During this process, the ER undergoes stress due to its remodelling and accumulation of viral particles and unfolded proteins, leading to an unfolded protein response (UPR). Here, we review the overall strategy used by JEV to infect the host cell and various cytopathic effects caused by JEV infection. We also highlight the role of JEV structural proteins (SPs) and non-structural proteins (NSPs) at various stages of the JEV life cycle that are involved in up- and downregulation of different host proteins and are potentially relevant for developing efficient therapeutic drugs.
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Affiliation(s)
- Sanjay Kumar
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067 India
- Center for Bioinformatics, Computational and Systems Biology, Pathfinder Research and Training Foundation, Greater Noida, India
| | - Akanksha Verma
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067 India
| | - Pardeep Yadav
- Department of Biotechnology, School of Engineering and Technology, Sharda University, Greater Noida, Uttar Pradesh 201310 India
- Center for Bioinformatics, Computational and Systems Biology, Pathfinder Research and Training Foundation, Greater Noida, India
| | | | - Esam Ibraheem Azhar
- Special Infectious Agents Unit-BSL3, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, 21589 Saudi Arabia
| | - S. S. Maitra
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067 India
| | - Vivek Dhar Dwivedi
- Center for Bioinformatics, Computational and Systems Biology, Pathfinder Research and Training Foundation, Greater Noida, India
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5
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Wu Z, Hu T, Chen W, Cheng Y, Wang M, Jia R, Zhu D, Liu M, Zhao X, Yang Q, Wu Y, Zhang S, Huang J, Mao S, Ou X, Gao Q, Sun D, Cheng A, Chen S. The autophagy-related degradation of MDA5 by Tembusu virus nonstructural 2B disrupts IFNβ production. FASEB J 2022; 36:e22417. [PMID: 35713934 DOI: 10.1096/fj.202101916rrr] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 05/23/2022] [Accepted: 06/06/2022] [Indexed: 12/24/2022]
Abstract
Duck Tembusu virus (TMUV) is a serious avian pathogen causing a decline in egg production, but the mechanism of the virus that breaks through the innate immune system is poorly understood. Here, we show that TMUV inhibits poly(I:C)-induced interferon (IFN) production. Because poly(I:C) transfection can specifically activate the MDA5 pathway in duck primary cells, we found that infection with TMUV can specifically target MDA5 and lead to its degradation. MDA5 downregulation could be blocked by the autophagy inhibitor 3-methyladenine (3-MA) but not a proteasome inhibitor, strongly implicating MDA5 degradation as an autophagy-related degradation pathway. Pretreatment with 3-MA enhanced the expression of MDA5 and inhibited TMUV replication. To screen TMUV proteins that degraded MDA5, the TMUV replicon and MDA5-Flag were cotransfected into cells, and the western blot analysis showed that nonstructural 2B (NS2B) can degrade MDA5 in a dose-dependent manner. Dual-luciferase assays indicate that NS2B alone inhibits MDA5- or poly(I:C)-mediated IFN production. NS2B binds MDA5 in the presence of 3-MA. The deletion of the amino acids of NS2B from residues 51 to 92 (hydrophilic area) restored the expression of MDA5 and relieved the MDA5-mediated IFNβ production inhibition by NS2B, indicating that the hydrophilic area of NS2B is important for its interaction with host innate immunity.
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Affiliation(s)
- Zhen Wu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Tao Hu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Weiqiong Chen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yao Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Mingshu Wang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Renyong Jia
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Dekang Zhu
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Mafeng Liu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Xinxin Zhao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Qiao Yang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Ying Wu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Shaqiu Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Juan Huang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Sai Mao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Xumin Ou
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Qun Gao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Di Sun
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Anchun Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Shun Chen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China
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6
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Lin X, Cheng J, Wu Y, Zhang Y, Jiang H, Wang J, Wang X, Cheng M. Identification and In Silico Binding Study of a Highly Potent DENV NS2B-NS3 Covalent Inhibitor. ACS Med Chem Lett 2022; 13:599-607. [PMID: 35450371 PMCID: PMC9014507 DOI: 10.1021/acsmedchemlett.1c00653] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 03/03/2022] [Indexed: 12/14/2022] Open
Abstract
Dengue virus (DENV), an arthropod-borne flavivirus, has developed rapidly in the past few decades and becoming the most widespread arbovirus in the world. The vital role of NS2B-NS3 in virus replication and maturation of viral proteins makes it the most promising target for anti-DENV drug discovery. In the current work, a potent NS2B-NS3 covalent inhibitor 23 (IC50 = 6.0 nM, k inac/K i = 1581 M-1 s-1) was discovered through the chemical modification of a published covalent inhibitor 1 (IC50 = 500 nM, k inac/K i = 156.1 M-1 s-1), followed by in vitro assay. Further comprehensive structure-activity relationship analysis through covalent docking and molecular dynamics simulation provides informative understanding of the binding modes of covalent inhibitors targeting NS2B-NS3.
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Affiliation(s)
- Xincheng Lin
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
- School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang 110016, China
- Key Laboratory of Intelligent Drug Design and New Drug Discovery of Liaoning Province, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Jiawei Cheng
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
- School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang 110016, China
- Key Laboratory of Intelligent Drug Design and New Drug Discovery of Liaoning Province, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Yuming Wu
- Department of Biotechnology, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Yaoliang Zhang
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
- School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang 110016, China
- Key Laboratory of Intelligent Drug Design and New Drug Discovery of Liaoning Province, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Hailun Jiang
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
- School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang 110016, China
- Key Laboratory of Intelligent Drug Design and New Drug Discovery of Liaoning Province, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Jian Wang
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
- School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang 110016, China
- Key Laboratory of Intelligent Drug Design and New Drug Discovery of Liaoning Province, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Xuejun Wang
- Department of Biotechnology, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Maosheng Cheng
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
- School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang 110016, China
- Key Laboratory of Intelligent Drug Design and New Drug Discovery of Liaoning Province, Shenyang Pharmaceutical University, Shenyang 110016, China
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7
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Wahaab A, Mustafa BE, Hameed M, Stevenson NJ, Anwar MN, Liu K, Wei J, Qiu Y, Ma Z. Potential Role of Flavivirus NS2B-NS3 Proteases in Viral Pathogenesis and Anti-flavivirus Drug Discovery Employing Animal Cells and Models: A Review. Viruses 2021; 14:44. [PMID: 35062249 PMCID: PMC8781031 DOI: 10.3390/v14010044] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 02/07/2023] Open
Abstract
Flaviviruses are known to cause a variety of diseases in humans in different parts of the world. There are very limited numbers of antivirals to combat flavivirus infection, and therefore new drug targets must be explored. The flavivirus NS2B-NS3 proteases are responsible for the cleavage of the flavivirus polyprotein, which is necessary for productive viral infection and for causing clinical infections; therefore, they are a promising drug target for devising novel drugs against different flaviviruses. This review highlights the structural details of the NS2B-NS3 proteases of different flaviviruses, and also describes potential antiviral drugs that can interfere with the viral protease activity, as determined by various studies. Moreover, optimized in vitro reaction conditions for studying the NS2B-NS3 proteases of different flaviviruses may vary and have been incorporated in this review. The increasing availability of the in silico and crystallographic/structural details of flavivirus NS2B-NS3 proteases in free and drug-bound states can pave the path for the development of promising antiflavivirus drugs to be used in clinics. However, there is a paucity of information available on using animal cells and models for studying flavivirus NS2B-NS3 proteases, as well as on the testing of the antiviral drug efficacy against NS2B-NS3 proteases. Therefore, on the basis of recent studies, an effort has also been made to propose potential cellular and animal models for the study of flavivirus NS2B-NS3 proteases for the purposes of exploring flavivirus pathogenesis and for testing the efficacy of possible drugs targets, in vitro and in vivo.
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Affiliation(s)
- Abdul Wahaab
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.H.); (M.N.A.); (K.L.); (J.W.)
| | - Bahar E Mustafa
- Sub Campus Toba Tek Singh, University of Agriculture, Faisalabad 36050, Pakistan;
| | - Muddassar Hameed
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.H.); (M.N.A.); (K.L.); (J.W.)
- Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Polytechnic Institute, State University, Fralin Life Sciences Building, 360 W Campus Blacksburg, Blacksburg, VA 24061, USA
| | - Nigel J. Stevenson
- Royal College of Surgeons in Ireland, Medical University of Bahrain, Busaiteen, Adliya 15503, Bahrain;
- Viral Immunology Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, D02 R590 Dublin, Ireland
| | - Muhammad Naveed Anwar
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.H.); (M.N.A.); (K.L.); (J.W.)
| | - Ke Liu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.H.); (M.N.A.); (K.L.); (J.W.)
| | - Jianchao Wei
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.H.); (M.N.A.); (K.L.); (J.W.)
| | - Yafeng Qiu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.H.); (M.N.A.); (K.L.); (J.W.)
| | - Zhiyong Ma
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.H.); (M.N.A.); (K.L.); (J.W.)
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8
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Shamim K, Xu M, Hu X, Lee EM, Lu X, Huang R, Shah P, Xu X, Chen CZ, Shen M, Guo H, Chen L, Itkin Z, Eastman RT, Shinn P, Klumpp-Thomas C, Michael S, Simeonov A, Lo DC, Ming GL, Song H, Tang H, Zheng W, Huang W. Application of niclosamide and analogs as small molecule inhibitors of Zika virus and SARS-CoV-2 infection. Bioorg Med Chem Lett 2021; 40:127906. [PMID: 33689873 PMCID: PMC7936759 DOI: 10.1016/j.bmcl.2021.127906] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/15/2021] [Accepted: 02/21/2021] [Indexed: 12/12/2022]
Abstract
Zika virus has emerged as a potential threat to human health globally. A previous drug repurposing screen identified the approved anthelminthic drug niclosamide as a small molecule inhibitor of Zika virus infection. However, as antihelminthic drugs are generally designed to have low absorption when dosed orally, the very limited bioavailability of niclosamide will likely hinder its potential direct repurposing as an antiviral medication. Here, we conducted SAR studies focusing on the anilide and salicylic acid regions of niclosamide to improve physicochemical properties such as microsomal metabolic stability, permeability and solubility. We found that the 5-bromo substitution in the salicylic acid region retains potency while providing better drug-like properties. Other modifications in the anilide region with 2′-OMe and 2′-H substitutions were also advantageous. We found that the 4′-NO2 substituent can be replaced with a 4′-CN or 4′-CF3 substituents. Together, these modifications provide a basis for optimizing the structure of niclosamide to improve systemic exposure for application of niclosamide analogs as drug lead candidates for treating Zika and other viral infections. Indeed, key analogs were also able to rescue cells from the cytopathic effect of SARS-CoV-2 infection, indicating relevance for therapeutic strategies targeting the COVID-19 pandemic.
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Affiliation(s)
- Khalida Shamim
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA.
| | - Miao Xu
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA
| | - Xin Hu
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA
| | - Emily M Lee
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA; Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
| | - Xiao Lu
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA
| | - Ruili Huang
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA
| | - Pranav Shah
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA
| | - Xin Xu
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA
| | - Catherine Z Chen
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA
| | - Min Shen
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA
| | - Hui Guo
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA
| | - Lu Chen
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA
| | - Zina Itkin
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA
| | - Richard T Eastman
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA
| | - Paul Shinn
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA
| | - Carleen Klumpp-Thomas
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA
| | - Sam Michael
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA
| | - Anton Simeonov
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA
| | - Donald C Lo
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA
| | - Guo-Li Ming
- Department of Neuroscience and Mahoney Institute for Neurosciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hongjun Song
- Department of Neuroscience and Mahoney Institute for Neurosciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hengli Tang
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
| | - Wei Zheng
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA
| | - Wenwei Huang
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892-3370, USA.
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9
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Li Z, Lang Y, Sakamuru S, Samrat S, Trudeau N, Kuo L, Rugenstein N, Tharappel A, D'Brant L, Koetzner CA, Hu S, Zhang J, Huang R, Kramer LD, Butler D, Xia M, Li H. Methylene blue is a potent and broad-spectrum inhibitor against Zika virus in vitro and in vivo. Emerg Microbes Infect 2020; 9:2404-2416. [PMID: 33078696 PMCID: PMC7646565 DOI: 10.1080/22221751.2020.1838954] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Many flaviviruses including the Dengue virus (DENV), Zika virus (ZIKV), West Nile virus, Yellow Fever virus, and Japanese encephalitis virus are significant human pathogens, unfortunately without any specific therapy. Here, we demonstrate that methylene blue, an FDA-approved drug, is a broad-spectrum and potent antiviral against Zika virus and Dengue virus both in vitro and in vivo. We found that methylene blue can considerably inhibit the interactions between viral protease NS3 and its NS2B co-factor, inhibit viral protease activity, inhibit viral growth, protect 3D mini-brain organoids from ZIKV infection, and reduce viremia in a mouse model. Mechanistic studies confirmed that methylene blue works in both entry and post entry steps, reduces virus production in replicon cells and inhibited production of processed NS3 protein. Overall, we have shown that methylene blue is a potent antiviral for management of flavivirus infections, particularly for Zika virus. As an FDA-approved drug, methylene blue is well-tolerated for human use. Therefore, methylene blue represents a promising and easily developed therapy for management of infections by ZIKV and other flaviviruses.
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Affiliation(s)
- Zhong Li
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Yuekun Lang
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Srilatha Sakamuru
- Division of Preclinical Innovation, National Institutes of Health Chemical Genomics Center, National Center for Advancing Translational Sciences, Rockville, Maryland, USA
| | - Subodh Samrat
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | | | - Lili Kuo
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | | | - Anil Tharappel
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | | | - Cheri A Koetzner
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Saiyang Hu
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Jing Zhang
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Ruili Huang
- Division of Preclinical Innovation, National Institutes of Health Chemical Genomics Center, National Center for Advancing Translational Sciences, Rockville, Maryland, USA
| | - Laura D Kramer
- Wadsworth Center, New York State Department of Health, Albany, NY, USA.,Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, USA
| | - David Butler
- The Neural Stem Cell Institute, Rensselaer, NY, USA
| | - Menghang Xia
- Division of Preclinical Innovation, National Institutes of Health Chemical Genomics Center, National Center for Advancing Translational Sciences, Rockville, Maryland, USA
| | - Hongmin Li
- Wadsworth Center, New York State Department of Health, Albany, NY, USA.,Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, USA
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10
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Lang Y, Li Z, Li H. Analysis of Protein-Protein Interactions by Split Luciferase Complementation Assay. ACTA ACUST UNITED AC 2020; 82:e90. [PMID: 31797579 DOI: 10.1002/cptx.90] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Protein-protein interactions are important in human disease. Developing and refining tools to understand physical contacts between signaling proteins is crucial. This article describes a split luciferase complementation (SLC) method designed to discover inhibitors of protein-protein interaction. Different fusion proteins with split luciferase are constructed, expressed, and purified, and then assessed to determine the best pair that generates the strongest luminescence. SLC specificity and affinity are further confirmed. Step-by-step instructions are provided for performing these assays using the NS2B-NS3 interaction as an example. NS2B is an essential cofactor for flaviviral NS3 protease function. Advantages and disadvantages of these assays are further discussed. © 2019 by John Wiley & Sons, Inc. Basic Protocol 1: Expression and purification of fusion proteins Basic Protocol 2: Analysis of prey/bait pairs by SLC-based NS2B-NS3 interaction assay Support Protocol 1: Interaction specificity assay Support Protocol 2: Competition binding assay: Dose-response inhibition using cold prey or bait Support Protocol 3: Competition binding assay: Inhibition by MBP-NS3 versus irrelevant MBP tag Support Protocol 4: SLC-based NS2B-NS3 interaction assay using NS2B mutations known to disrupt NS2B-NS3 interactions.
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Affiliation(s)
- Yuekun Lang
- Wadsworth Center, New York State Department of Health, Albany, New York
| | - Zhong Li
- Wadsworth Center, New York State Department of Health, Albany, New York
| | - Hongmin Li
- Wadsworth Center, New York State Department of Health, Albany, New York.,Department of Biomedical Sciences, School of Public Health, State University of New York at Albany, Albany, New York
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11
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West Nile Virus: An Update on Pathobiology, Epidemiology, Diagnostics, Control and "One Health" Implications. Pathogens 2020; 9:pathogens9070589. [PMID: 32707644 PMCID: PMC7400489 DOI: 10.3390/pathogens9070589] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 07/16/2020] [Accepted: 07/16/2020] [Indexed: 02/06/2023] Open
Abstract
West Nile virus (WNV) is an important zoonotic flavivirus responsible for mild fever to severe, lethal neuroinvasive disease in humans, horses, birds, and other wildlife species. Since its discovery, WNV has caused multiple human and animal disease outbreaks in all continents, except Antarctica. Infections are associated with economic losses, mainly due to the cost of treatment of infected patients, control programmes, and loss of animals and animal products. The pathogenesis of WNV has been extensively investigated in natural hosts as well as in several animal models, including rodents, lagomorphs, birds, and reptiles. However, most of the proposed pathogenesis hypotheses remain contentious, and much remains to be elucidated. At the same time, the unavailability of specific antiviral treatment or effective and safe vaccines contribute to the perpetuation of the disease and regular occurrence of outbreaks in both endemic and non-endemic areas. Moreover, globalisation and climate change are also important drivers of the emergence and re-emergence of the virus and disease. Here, we give an update of the pathobiology, epidemiology, diagnostics, control, and “One Health” implications of WNV infection and disease.
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12
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Insights into Structures and Dynamics of Flavivirus Proteases from NMR Studies. Int J Mol Sci 2020; 21:ijms21072527. [PMID: 32260545 PMCID: PMC7177695 DOI: 10.3390/ijms21072527] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 03/29/2020] [Accepted: 03/31/2020] [Indexed: 12/29/2022] Open
Abstract
Nuclear magnetic resonance (NMR) spectroscopy plays important roles in structural biology and drug discovery, as it is a powerful tool to understand protein structures, dynamics, and ligand binding under physiological conditions. The protease of flaviviruses is an attractive target for developing antivirals because it is essential for the maturation of viral proteins. High-resolution structures of the proteases in the absence and presence of ligands/inhibitors were determined using X-ray crystallography, providing structural information for rational drug design. Structural studies suggest that proteases from Dengue virus (DENV), West Nile virus (WNV), and Zika virus (ZIKV) exist in open and closed conformations. Solution NMR studies showed that the closed conformation is predominant in solution and should be utilized in structure-based drug design. Here, we reviewed solution NMR studies of the proteases from these viruses. The accumulated studies demonstrated that NMR spectroscopy provides additional information to understand conformational changes of these proteases in the absence and presence of substrates/inhibitors. In addition, NMR spectroscopy can be used for identifying fragment hits that can be further developed into potent protease inhibitors.
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13
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Karothia D, Kumar Dash P, Parida M, Bhagyawant SS, Kumar JS. Vector derived artificial miRNA mediated inhibition of West Nile virus replication and protein expression. Gene 2020; 729:144300. [DOI: 10.1016/j.gene.2019.144300] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 12/16/2019] [Indexed: 02/03/2023]
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14
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Nasar S, Rashid N, Iftikhar S. Dengue proteins with their role in pathogenesis, and strategies for developing an effective anti-dengue treatment: A review. J Med Virol 2019; 92:941-955. [PMID: 31784997 DOI: 10.1002/jmv.25646] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 11/26/2019] [Indexed: 12/16/2022]
Abstract
Dengue virus is an arbovirus belonging to class Flaviviridae Its clinical manifestation ranges from asymptomatic to extreme conditions (dengue hemorrhagic fever/dengue shock syndrome). A lot of research has been done on this ailment, yet there is no effective treatment available for the disease. This review provides the systematic understanding of all dengue proteins, role of its structural proteins (C-protein, E-protein, prM) in virus entry, assembly, and secretion in host cell, and nonstructural proteins (NS1, NS2a, NS2b, NS3, NS4a, NS4b, and NS5) in viral assembly, replication, and immune evasion during dengue progression and pathogenesis. Furthermore, the review has highlighted the controversies related to the only commercially available dengue vaccine, that is, Dengvaxia, and the risk associated with it. Lastly, it provides an insight regarding various approaches for developing an effective anti-dengue treatment.
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Affiliation(s)
- Sitara Nasar
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
| | - Naeem Rashid
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
| | - Saima Iftikhar
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
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15
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Nutho B, Mulholland AJ, Rungrotmongkol T. Quantum Mechanics/Molecular Mechanics (QM/MM) Calculations Support a Concerted Reaction Mechanism for the Zika Virus NS2B/NS3 Serine Protease with Its Substrate. J Phys Chem B 2019; 123:2889-2903. [PMID: 30845796 DOI: 10.1021/acs.jpcb.9b02157] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Zika virus (ZIKV) is mainly transmitted to humans by Aedes species mosquitoes and is associated with serious pathological disorders including microcephaly in newborns and Guillain-Barré syndrome in adults. Currently, there is no vaccine or anti-ZIKV drug available for preventing or controlling ZIKV infection. An attractive drug target for ZIKV treatment is a two-compartment (NS2B/NS3) serine protease that processes viral polyprotein during infection. Here, conventional molecular dynamics simulations of the ZIKV protease in complex with peptide substrate (TGKRS) sequence at the C-terminus of NS2B show that the substrate is in the active conformation for the cleavage reaction by ZIKV protease. Hybrid quantum mechanics/molecular mechanics (QM/MM) umbrella sampling simulations (PM6/ff14SB) of acylation results reveal that proton transfer from S135 to H51 and nucleophilic attack on the substrate by S135 are concerted. The rate-limiting step involves the formation of a tetrahedral intermediate. In addition, the single-point energy QM/MM calculations, precisely at the level of coupled cluster theory (LCCSD(T)/(aug)-cc-pVTZ), were performed to correct the potential energy profiles for the first step of the acylation process. The average computed activation barrier at this level of theory is 16.3 kcal mol-1. Therefore, the computational approaches presented here are helpful for further designing of NS2B/NS3 inhibitors based on transition-state analogues.
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Affiliation(s)
| | - Adrian J Mulholland
- Centre for Computational Chemistry, School of Chemistry , University of Bristol , Bristol BS8 1TS , U.K
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16
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Chen J, Jiang H, Li F, Hu B, Wang Y, Wang M, Wang J, Cheng M. Computational insight into dengue virus NS2B-NS3 protease inhibition: A combined ligand- and structure-based approach. Comput Biol Chem 2018; 77:261-271. [DOI: 10.1016/j.compbiolchem.2018.09.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 09/10/2018] [Accepted: 09/12/2018] [Indexed: 01/15/2023]
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17
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Gopala Reddy SB, Chin WX, Shivananju NS. Dengue virus NS2 and NS4: Minor proteins, mammoth roles. Biochem Pharmacol 2018; 154:54-63. [PMID: 29674002 DOI: 10.1016/j.bcp.2018.04.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Accepted: 04/10/2018] [Indexed: 12/11/2022]
Abstract
Despite the ever-increasing global incidence of dengue fever, there are no specific chemotherapy regimens for its treatment. Structural studies on dengue virus (DENV) proteins have revealed potential drug targets. Major DENV proteins such as the envelope protein and non-structural (NS) proteins 3 and 5 have been extensively investigated in antiviral studies, but with limited success in vitro. However, the minor NS proteins NS2 and NS4 have remained relatively underreported. Emerging evidence indicating their indispensable roles in virus propagation and host immunomodulation should encourage us to target these proteins for drug discovery. This review covers current knowledge on DENV NS2 and NS4 proteins from structural and functional perspectives and assesses their potential as targets for antiviral design. Antiviral targets in NS2A include surface-exposed transmembrane regions involved in pathogenesis, while those in NS2B include protease-binding sites in a conserved hydrophilic domain. Ideal drug targets in NS4A include helix α4 and the PEPEKQR sequence, which are essential for NS4A-2K cleavage and NS4A-NS4B association, respectively. In NS4B, the cytoplasmic loop connecting helices α5 and α7 is an attractive target for antiviral design owing to its role in dimerization and NS4B-NS3 interaction. Findings implicating NS2A, NS2B, and NS4A in membrane-modulation and viroporin-like activities indicate an opportunity to target these proteins by disrupting their association with membrane lipids. Despite the lack of 3D structural data, recent topological findings and progress in structure-prediction methods should be sufficient impetus for targeting NS2 and NS4 for drug design.
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Affiliation(s)
- Sindhoora Bhargavi Gopala Reddy
- Department of Biotechnology, Sri Jayachamarajendra College of Engineering, JSS Science and Technology University, JSS TEI Campus, Mysuru 57006, Karnataka, India
| | - Wei-Xin Chin
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Nanjunda Swamy Shivananju
- Department of Biotechnology, Sri Jayachamarajendra College of Engineering, JSS Science and Technology University, JSS TEI Campus, Mysuru 57006, Karnataka, India.
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18
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Abstract
West Nile virus (WNV) is an arbovirus with increased global incidence in the last decade. It is also a major cause of human encephalitis in the USA. WNV is an arthropod-transmitted virus that mainly affects birds but humans become infected as incidental dead-end hosts which can cause outbreaks in naïve populations. The main vectors of WNV are mosquitoes of the genus Culex, which preferentially feed on birds. As in many other arboviruses, the characteristics that allow Flaviviruses like WNV to replicate and transmit to different hosts are encrypted in their genome, which also contains information for the production of structural and nonstructural proteins needed for host cell infection. WNV and other Flaviviruses have developed different strategies to establish infection, replication, and successful transmission. Most of these strategies include the diversion of the host's immune responses away from the virus. In this review, we describe the molecular structure and protein function of WNV with emphasis on protein involvement in the modulation of antiviral immune responses.
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19
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STD-NMR experiments identify a structural motif with novel second-site activity against West Nile virus NS2B-NS3 protease. Antiviral Res 2017; 146:174-183. [PMID: 28927677 DOI: 10.1016/j.antiviral.2017.09.008] [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: 08/04/2017] [Revised: 09/09/2017] [Accepted: 09/14/2017] [Indexed: 11/22/2022]
Abstract
West Nile virus (WNV) belongs to the genus Flavivirus of the family Flaviviridae. This mosquito-borne virus that is highly pathogenic to humans has been evolving into a global threat during the past two decades. Despite many efforts, neither antiviral drugs nor vaccines are available. The viral protease NS2B-NS3pro is essential for viral replication, and therefore it is considered a prime drug target. However, success in the development of specific NS2B-NS3pro inhibitors had been moderate so far. In the search for new structural motifs with binding affinity for NS2B-NS3pro, we have screened a fragment library, the Maybridge Ro5 library, employing saturation transfer difference (STD) NMR experiments as readout. About 30% of 429 fragments showed binding to NS2B-NS3pro. Subsequent STD-NMR competition experiments using the known active site fragment A as reporter ligand yielded 14 competitively binding fragments, and 22 fragments not competing with A. In a fluorophore-based protease assay, all of these fragments showed inhibition in the micromolar range. Interestingly, 10 of these 22 fragments showed a notable increase of STD intensities in the presence of compound A suggesting cooperative binding. The most promising non-competitive inhibitors 1 and 2 (IC50 ∼ 500 μM) share a structural motif that may guide the development of novel second-site (potentially allosteric) inhibitors of NS2B-NS3pro. To identify the matching protein binding site, chemical shift perturbation studies employing 1H,15N-TROSY-HSQC experiments with uniformly 2H,15N-labeled protease were performed in the presence of 1, and in the concomitant absence or presence of A. The data suggest that 1 interacts with Met 52* of NS2B, identifying a secondary site adjacent to the binding site of A. Therefore, our study paves the way for the synthesis of novel bidentate NS2B-NS3pro inhibitors.
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20
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Li Z, Brecher M, Deng YQ, Zhang J, Sakamuru S, Liu B, Huang R, Koetzner CA, Allen CA, Jones SA, Chen H, Zhang NN, Tian M, Gao F, Lin Q, Banavali N, Zhou J, Boles N, Xia M, Kramer LD, Qin CF, Li H. Existing drugs as broad-spectrum and potent inhibitors for Zika virus by targeting NS2B-NS3 interaction. Cell Res 2017; 27:1046-1064. [PMID: 28685770 DOI: 10.1038/cr.2017.88] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 05/19/2017] [Accepted: 06/05/2017] [Indexed: 02/07/2023] Open
Abstract
Recent outbreaks of Zika virus (ZIKV) highlight an urgent need for therapeutics. The protease complex NS2B-NS3 plays essential roles during flaviviral polyprotein processing, and thus represents an attractive drug target. Here, we developed a split luciferase complementation-based high-throughput screening assay to identify orthosteric inhibitors that directly target flavivirus NS2B-NS3 interactions. By screening a total of 2 816 approved and investigational drugs, we identified three potent candidates, temoporfin, niclosamide, and nitazoxanide, as flavivirus NS2B-NS3 interaction inhibitors with nanomolar potencies. Significantly, the most potent compound, temoporfin, not only inhibited ZIKV replication in human placental and neural progenitor cells, but also prevented ZIKV-induced viremia and mortality in mouse models. Structural docking suggests that temoporfin potentially binds NS3 pockets that hold critical NS2B residues, thus inhibiting flaviviral polyprotein processing in a non-competitive manner. As these drugs have already been approved for clinical use in other indications either in the USA or other countries, they represent promising and easily developed therapies for the management of infections by ZIKV and other flaviviruses.
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Affiliation(s)
- Zhong Li
- Wadsworth Center, New York State Department of Health, 120 New Scotland Ave, Albany, NY 12208, USA
| | - Matthew Brecher
- Wadsworth Center, New York State Department of Health, 120 New Scotland Ave, Albany, NY 12208, USA
| | - Yong-Qiang Deng
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Jing Zhang
- Wadsworth Center, New York State Department of Health, 120 New Scotland Ave, Albany, NY 12208, USA
| | - Srilatha Sakamuru
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892, USA
| | - Binbin Liu
- Wadsworth Center, New York State Department of Health, 120 New Scotland Ave, Albany, NY 12208, USA.,Department of Food Science, College of Food Science and Technology, Guangdong Ocean University, Zhanjiang, Guangdong 524000, China
| | - Ruili Huang
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892, USA
| | - Cheri A Koetzner
- Wadsworth Center, New York State Department of Health, 120 New Scotland Ave, Albany, NY 12208, USA
| | - Christina A Allen
- The Neural Stem Cell Institute, 1 Discovery Drive, Rensselaer, NY 12144, USA
| | - Susan A Jones
- Wadsworth Center, New York State Department of Health, 120 New Scotland Ave, Albany, NY 12208, USA
| | - Haiying Chen
- Department of Pharmacology and Toxicology, Chemical Biology Program, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Na-Na Zhang
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Min Tian
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Fengshan Gao
- Wadsworth Center, New York State Department of Health, 120 New Scotland Ave, Albany, NY 12208, USA.,Department of Biochemistry and Molecular Biology, College of Life Science and Technology, Dalian University, Dalian, Liaoning 116622, China
| | - Qishan Lin
- Center for Functional Genomics, University at Albany, Rensselaer, NY 12144, USA
| | - Nilesh Banavali
- Wadsworth Center, New York State Department of Health, 120 New Scotland Ave, Albany, NY 12208, USA.,Department of Biomedical Sciences, School of Public Health, University at Albany, PO Box 509, Empire State Plaza, Albany, NY 12201, USA
| | - Jia Zhou
- Department of Pharmacology and Toxicology, Chemical Biology Program, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Nathan Boles
- The Neural Stem Cell Institute, 1 Discovery Drive, Rensselaer, NY 12144, USA
| | - Menghang Xia
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892, USA
| | - Laura D Kramer
- Wadsworth Center, New York State Department of Health, 120 New Scotland Ave, Albany, NY 12208, USA.,Department of Biomedical Sciences, School of Public Health, University at Albany, PO Box 509, Empire State Plaza, Albany, NY 12201, USA
| | - Cheng-Feng Qin
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.,Guangzhou Eighth People's Hospital, Guangzhou Medical University, Guangzhou, Guangdong 510060, China
| | - Hongmin Li
- Wadsworth Center, New York State Department of Health, 120 New Scotland Ave, Albany, NY 12208, USA.,Department of Biomedical Sciences, School of Public Health, University at Albany, PO Box 509, Empire State Plaza, Albany, NY 12201, USA
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21
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A conformational switch high-throughput screening assay and allosteric inhibition of the flavivirus NS2B-NS3 protease. PLoS Pathog 2017; 13:e1006411. [PMID: 28542603 PMCID: PMC5462475 DOI: 10.1371/journal.ppat.1006411] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 06/07/2017] [Accepted: 05/15/2017] [Indexed: 12/02/2022] Open
Abstract
The flavivirus genome encodes a single polyprotein precursor requiring multiple cleavages by host and viral proteases in order to produce the individual proteins that constitute an infectious virion. Previous studies have revealed that the NS2B cofactor of the viral NS2B-NS3 heterocomplex protease displays a conformational dynamic between active and inactive states. Here, we developed a conformational switch assay based on split luciferase complementation (SLC) to monitor the conformational change of NS2B and to characterize candidate allosteric inhibitors. Binding of an active-site inhibitor to the protease resulted in a conformational change of NS2B and led to significant SLC enhancement. Mutagenesis of key residues at an allosteric site abolished this induced conformational change and SLC enhancement. We also performed a virtual screen of NCI library compounds to identify allosteric inhibitors, followed by in vitro biochemical screening of the resultant candidates. Only three of these compounds, NSC135618, 260594, and 146771, significantly inhibited the protease of Dengue virus 2 (DENV2) in vitro, with IC50 values of 1.8 μM, 11.4 μM, and 4.8 μM, respectively. Among the three compounds, only NSC135618 significantly suppressed the SLC enhancement triggered by binding of active-site inhibitor in a dose-dependent manner, indicating that it inhibits the conformational change of NS2B. Results from virus titer reduction assays revealed that NSC135618 is a broad spectrum flavivirus protease inhibitor, and can significantly reduce titers of DENV2, Zika virus (ZIKV), West Nile virus (WNV), and Yellow fever virus (YFV) on A549 cells in vivo, with EC50 values in low micromolar range. In contrast, the cytotoxicity of NSC135618 is only moderate with CC50 of 48.8 μM on A549 cells. Moreover, NSC135618 inhibited ZIKV in human placental and neural progenitor cells relevant to ZIKV pathogenesis. Results from binding, kinetics, Western blot, mass spectrometry and mutagenesis experiments unambiguously demonstrated an allosteric mechanism for inhibition of the viral protease by NSC135618.
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22
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Product release is rate-limiting for catalytic processing by the Dengue virus protease. Sci Rep 2016; 6:37539. [PMID: 27897196 PMCID: PMC5126634 DOI: 10.1038/srep37539] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 10/31/2016] [Indexed: 12/17/2022] Open
Abstract
Dengue Virus (DENV) is the most prevalent global arbovirus, yet despite an increasing burden to health care there are currently no therapeutics available to treat infection. A potential target for antiviral drugs is the two-component viral protease NS2B-NS3pro, which is essential for viral replication. Interactions between the two components have been investigated here by probing the effect on the rate of enzyme catalysis of key mutations in a mobile loop within NS2B that is located at the interface of the two components. Steady-state kinetic assays indicated that the mutations greatly affect catalytic turnover. However, single turnover and fluorescence experiments have revealed that the mutations predominantly affect product release rather than substrate binding. Fluorescence analysis also indicated that the addition of substrate triggers a near-irreversible change in the enzyme conformation that activates the catalytic centre. Based on this mechanistic insight, we propose that residues within the mobile loop of NS2B control product release and present a new target for design of potent Dengue NS2B-NS3 protease inhibitors.
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23
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David S, Abraham AM. Epidemiological and clinical aspects on West Nile virus, a globally emerging pathogen. Infect Dis (Lond) 2016; 48:571-86. [PMID: 27207312 DOI: 10.3109/23744235.2016.1164890] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Since the isolation of West Nile virus (WNV) in 1937, in Uganda, it has spread globally, causing significant morbidity and mortality. While birds serve as amplifier hosts, mosquitoes of the Culex genus function as vectors. Humans and horses are dead end hosts. The clinical manifestations of West Nile infection in humans range from asymptomatic illness to West Nile encephalitis. METHODS The laboratory offers an array of tests, the preferred method being detection of RNA and serum IgM for WNV, which, if detected, confirms the clinical diagnosis. Although no definitive antiviral therapy and vaccine are available for humans, many approaches are being studied. STUDY This article will review the current literature of the natural cycle, geographical distribution, virology, replication cycle, molecular epidemiology, pathogenesis, laboratory diagnosis, clinical manifestations, blood donor screening for WNV, treatment, prevention and vaccines.
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Affiliation(s)
- Shoba David
- a Department of Clinical Virology , Christian Medical College , Vellore , Tamil Nadu , India
| | - Asha Mary Abraham
- a Department of Clinical Virology , Christian Medical College , Vellore , Tamil Nadu , India
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Li Y, Li Q, Wong YL, Liew LSY, Kang C. Membrane topology of NS2B of dengue virus revealed by NMR spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:2244-52. [DOI: 10.1016/j.bbamem.2015.06.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 05/20/2015] [Accepted: 06/09/2015] [Indexed: 12/27/2022]
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Dengue protease activity: the structural integrity and interaction of NS2B with NS3 protease and its potential as a drug target. Biosci Rep 2015; 31:399-409. [PMID: 21329491 DOI: 10.1042/bsr20100142] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Flaviviral NS3 serine proteases require the NS2B cofactor region (cNS2B) to be active. Recent crystal structures of WNV (West Nile virus) protease in complex with inhibitors revealed that cNS2B participates in the formation of the protease active site. No crystal structures of ternary complexes are currently available for DENV (dengue virus) to validate the role of cNS2B in active site formation. In the present study, a GST (glutathione transferase) fusion protein of DENV-2 cNS2B49-95 was used as a bait to pull down DENV-2 protease domain (NS3pro). The affinity of NS3pro for cNS2B was strong (equilibrium-binding constant <200 nM) and the heterodimeric complex displayed a catalytic efficiency similar to that of single-chain DENV-2 cNS2B/NS3pro. Various truncations and mutations in the cNS2B sequence showed that conformational integrity of the entire 47 amino acids is critical for protease activity. Furthermore, DENV-2 NS3 protease can be pulled down and transactivated by cNS2B cofactors from DENV-1, -3, -4 and WNV, suggesting that mechanisms for activation are conserved across the flavivirus genus. To validate NS2B as a potential target in allosteric inhibitor development, a cNS2B-specific human monoclonal antibody (3F10) was utilized. 3F10 disrupted the interaction between cNS2B and NS3 in vitro and reduced DENV viral replication in HEK (human embryonic kidney)-293 cells. This provides proof-of-concept for developing assays to find inhibitors that block the interaction between NS2B and NS3 during viral translation.
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Huhtamo E, Cook S, Moureau G, Uzcátegui NY, Sironen T, Kuivanen S, Putkuri N, Kurkela S, Harbach RE, Firth AE, Vapalahti O, Gould EA, de Lamballerie X. Novel flaviviruses from mosquitoes: mosquito-specific evolutionary lineages within the phylogenetic group of mosquito-borne flaviviruses. Virology 2014; 464-465:320-329. [PMID: 25108382 PMCID: PMC4170750 DOI: 10.1016/j.virol.2014.07.015] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 03/07/2014] [Accepted: 07/01/2014] [Indexed: 01/17/2023]
Abstract
Novel flaviviruses that are genetically related to pathogenic mosquito-borne flaviviruses (MBFV) have been isolated from mosquitoes in various geographical locations, including Finland. We isolated and characterized another novel virus of this group from Finnish mosquitoes collected in 2007, designated as Ilomantsi virus (ILOV). Unlike the MBFV that infect both vertebrates and mosquitoes, the MBFV-related viruses appear to be specific to mosquitoes similar to the insect-specific flaviviruses (ISFs). In this overview of MBFV-related viruses we conclude that they differ from the ISFs genetically and antigenically. Phylogenetic analyses separated the MBFV-related viruses isolated in Africa, the Middle East and South America from those isolated in Europe and Asia. Serological cross-reactions of MBFV-related viruses with other flaviviruses and their potential for vector-borne transmission require further characterization. The divergent MBFV-related viruses are probably significantly under sampled to date and provide new information on the variety, properties and evolution of vector-borne flaviviruses. Mosquito-borne flavivirus-related viruses were isolated from Finnish mosquitoes. Isolates were reactive with flavivirus antibodies but appeared mosquito-specific. Sequence analysis identified related viruses from different parts of the world. These viruses represent unique properties among the mosquito-borne flavivirus group.
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Affiliation(s)
- Eili Huhtamo
- Department of Virology, Haartman Institute, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
| | - Shelley Cook
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, United Kingdom
| | - Gregory Moureau
- UMR D 190 "Emergence des Pathologies Virales", Aix Marseille University, IRD French Institute of Research for Development, EHESP French School of Public Health, 27 Boulevard Jean Moulin, Marseille 13005, France
| | - Nathalie Y Uzcátegui
- Department of Virology, Haartman Institute, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Tarja Sironen
- Department of Virology, Haartman Institute, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Suvi Kuivanen
- Department of Virology, Haartman Institute, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Niina Putkuri
- Department of Virology, Haartman Institute, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Satu Kurkela
- Department of Virology, Haartman Institute, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Department of Virology and Immunology, Helsinki University Central Hospital Laboratory (HUSLAB), P.O. Box 400, Haartmaninkatu 3, 00029 HUS, Helsinki, Finland
| | - Ralph E Harbach
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, United Kingdom
| | - Andrew E Firth
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge CB2 1QP, United Kingdom
| | - Olli Vapalahti
- Department of Virology, Haartman Institute, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Department of Virology and Immunology, Helsinki University Central Hospital Laboratory (HUSLAB), P.O. Box 400, Haartmaninkatu 3, 00029 HUS, Helsinki, Finland; Division of Microbiology and Epidemiology, Department of Basic Veterinary Sciences, University of Helsinki, Helsinki, Finland
| | - Ernest A Gould
- UMR D 190 "Emergence des Pathologies Virales", Aix Marseille University, IRD French Institute of Research for Development, EHESP French School of Public Health, 27 Boulevard Jean Moulin, Marseille 13005, France
| | - Xavier de Lamballerie
- UMR D 190 "Emergence des Pathologies Virales", Aix Marseille University, IRD French Institute of Research for Development, EHESP French School of Public Health, 27 Boulevard Jean Moulin, Marseille 13005, France
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Functional interplay among the flavivirus NS3 protease, helicase, and cofactors. Virol Sin 2014; 29:74-85. [PMID: 24691778 DOI: 10.1007/s12250-014-3438-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 03/19/2014] [Indexed: 12/22/2022] Open
Abstract
Flaviviruses are positive-sense RNA viruses, and many are important human pathogens. Nonstructural protein 2B and 3 of the flaviviruses (NS2BNS3) form an endoplasmic reticulum (ER) membrane-associated hetero-dimeric complex through the NS2B transmembrane region. The NS2BNS3 complex is multifunctional. The N-terminal region of NS3, and its cofactor NS2B fold into a protease that is responsible for viral polyprotein processing, and the C-terminal domain of NS3 possesses NTPase/RNA helicase activities and is involved in viral RNA replication and virus particle formation. In addition, NS2BNS3 complex has also been shown to modulate viral pathogenesis and the host immune response. Because of the essential functions that the NS2BNS3 complex plays in the flavivirus life cycle, it is an attractive target for antiviral development. This review focuses on the recent biochemical and structural advances of NS2BNS3 and provides a brief update on the current status of drug development targeting this viral protein complex.
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de la Cruz L, Chen WN, Graham B, Otting G. Binding mode of the activity-modulating C-terminal segment of NS2B to NS3 in the dengue virus NS2B-NS3 protease. FEBS J 2014; 281:1517-33. [PMID: 24472363 DOI: 10.1111/febs.12729] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 01/21/2014] [Accepted: 01/24/2014] [Indexed: 12/16/2022]
Abstract
The two-component dengue virus NS2B-NS3 protease (NS2B-NS3pro) is an established drug target but inhibitor design is hampered by uncertainties about its 3D structure in solution. Crystal structures reported very different conformations for the functionally important C-terminal segment of the NS2B cofactor (NS2Bc), indicating open and closed conformations in the absence and presence of inhibitors, respectively. An earlier NMR study in solution indicated that a closed state is the preferred conformation in the absence of an artificial linker engineered between NS2B and NS3pro. To obtain direct structural information on the fold of unlinked NS2B-NS3pro in solution, we tagged NS3pro with paramagnetic tags and measured pseudocontact shifts by NMR to position NS2Bc relative to NS3pro. NS2Bc was found to bind to NS3pro in the same way as reported in a previously published model and crystal structure of the closed state. The structure is destabilized, however, by high ionic strength and basic pH, showing the importance of electrostatic forces to tie NS2Bc to NS3pro. Narrow NMR signals previously thought to represent the open state are associated with protein degradation. In conclusion, the closed conformation of the NS2B-NS3 protease is the best model for structure-guided drug design.
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Affiliation(s)
- Laura de la Cruz
- Research School of Chemistry, Australian National University, Canberra, Australia
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Junaid M, Angsuthanasombat C, Wikberg JES, Ali N, Katzenmeier G. A straightforward experimental approach to expression, purification, refolding, and enzymatic analysis of recombinant dengue virus NS2B(H)-NS3pro protease. BIOCHEMISTRY. BIOKHIMIIA 2013; 78:920-4. [PMID: 24228881 DOI: 10.1134/s0006297913080099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Dengue virus threatens around 2.5 billion people worldwide; about 50 million become infected every year, and yet no vaccine or drug is available for prevention and/or treatment. The flaviviral NS2B-NS3pro complex is indispensable for flaviviral replication and is considered to be an important drug target. The aim of this study was to develop a simple and generally applicable experimental strategy to construct, purify, and assay a highly active recombinant NS2B(H)-NS3pro complex that would be useful for high-throughput screening of potential inhibitors. The sequence of NS2B(H)-NS3pro was generated by overlap extension PCR (SOE-PCR) and cloned into the pTrcHisA vector. Hexahistidine-tagged NS2B(H)-NS3pro complex was expressed in E. coli predominantly as insoluble protein and purified to >95% purity by single-step immobilized metal affinity chromatography. SDS-PAGE followed by immunoblotting of the purified enzyme demonstrated the presence of the NS2B(H)-NS3pro precursor and its autocleavage products, NS3pro and NS2B(H), as 37, 21, and 10 kDa bands, respectively. Kinetic parameters, Km, kcat, and kcat/Km for the fluorophore-linked protease model substrate Ac-nKRR-amc were obtained using inner-filter effect correction. The kinetic parameters Km, kcat, and kcat/Km for Ac-nKRR-amc substrate were 100 µM, 0.112 s(-1), and 1120 M(-1)·s(-1), respectively. A simplified procedure for the cloning, overexpression, and purification of the NS2B(H)-NS3pro complex was applied, and a highly active recombinant NS2B(H)-NS3pro complex was obtained that could be useful for the design of high-throughput assays aimed at flaviviral inhibitor discovery.
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Affiliation(s)
- M Junaid
- Department of Pharmacy, University of Malakand, Chakdara, 18550 Pakistan.
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The flavivirus protease as a target for drug discovery. Virol Sin 2013; 28:326-36. [PMID: 24242363 DOI: 10.1007/s12250-013-3390-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 11/01/2013] [Indexed: 01/27/2023] Open
Abstract
Many flaviviruses are significant human pathogens causing considerable disease burdens, including encephalitis and hemorrhagic fever, in the regions in which they are endemic. A paucity of treatments for flaviviral infections has driven interest in drug development targeting proteins essential to flavivirus replication, such as the viral protease. During viral replication, the flavivirus genome is translated as a single polyprotein precursor, which must be cleaved into individual proteins by a complex of the viral protease, NS3, and its cofactor, NS2B. Because this cleavage is an obligate step of the viral life-cycle, the flavivirus protease is an attractive target for antiviral drug development. In this review, we will survey recent drug development studies targeting the NS3 active site, as well as studies targeting an NS2B/NS3 interaction site determined from flavivirus protease crystal structures.
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Jia F, Fan J, Zhang B, Yuan Z. Mutagenesis of D80-82 and G83 residues in West Nile Virus NS2B: effects on NS2B-NS3 activity and viral replication. Virol Sin 2013; 28:16-23. [PMID: 23325418 DOI: 10.1007/s12250-013-3276-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 12/28/2012] [Indexed: 12/01/2022] Open
Abstract
Flaviviral NS2B is a required cofactor for NS3 serine protease activity and plays an important role in promoting functional NS2B-NS3 protease configuration and maintaining critical interactions with protease catalysis substrates. The residues D(80)DDG in West Nile virus (WNV) NS2B are important for protease activity. To investigate the effects of D(80)DDG in NS2B on protease activity and viral replication, the negatively charged region D(80)DD and the conserved residue G83 of NS2B were mutated (D(80)DD/E(80)EE, D(80)DD/K(80)KK, D(80)DD/A(80)AA, G83F, G83S, G83D, G83K, and G83A), and NS3 D75A was designated as the negative control. The effects of the mutations on NS2B-NS3 activity, viral translation, and viral RNA replication were analyzed using kinetic analysis of site-directed enzymes and a transient replicon assay. All substitutions resulted in significantly decreased enzyme activity and blocked RNA replication. The negative charge of D(80)DD is not important for maintaining NS2B function, but side chain changes in G83 have dramatic effects on protease activity and RNA replication. These results demonstrate that NS2B is important for viral replication and that D(80)DD and G83 substitutions prevent replication; they will be useful for understanding the relationship between NS2B and NS3.
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Affiliation(s)
- Fan Jia
- Key Laboratory of Agricultural and Environmental Microbiology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China
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Seniya C, Mishra H, Yadav A, Sagar N, Chaturvedi B, Uchadia K, Wadhwa G. Antiviral potential of 4-hydroxypanduratin A, secondary metabolite of Fingerroot, Boesenbergia pandurata (Schult.), towards Japanese Encephalitis virus NS2B/NS3 protease. Bioinformation 2013; 9:54-60. [PMID: 23390345 PMCID: PMC3563417 DOI: 10.6026/97320630009054] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 12/21/2012] [Accepted: 12/22/2012] [Indexed: 11/29/2022] Open
Abstract
4-hydroxypanduratin A is a secondary metabolite of Boesenbergia pandurata Schult. (Fingerroot) plant with various pharmacological
activities such as neuroprotective, potent antioxidant, antibacterial and antifungal. Flaviviral NS2B/NS3 protease activity is
essential for polyprotein processing and viral replication for Japanese Encephalitis Virus (JEV), a major cause of Acute Encephaltis in
Asia. Inhibition of formation of this complex by arresting the binding of NS2B with NS3 would reduce the enzyme's activity to
meager proportions and hence would prevent further viral proliferation. The automated 3D structure of NS2B protein of the JEV
GP78 was predicted based on the sequence-to-structure-to-function paradigm using I-TASSER and the function of NS2B protein
was inferred by matching to other known proteins. The stereochemical quality of predicted structure was checked by PROCHECK.
The antiviral activity of 4-hydroxypanduratin A against NS2B protein as a potential drug has been elucidated in this paper.
Docking simulation analysis showed 4-hydroxypanduratin A as potential inhibitor of NS2B protein/cofactor which is necessary for
NS3 protease activity. 220 derivatives of 4-hydroxypanduratin A were virtually screened with rigid criteria of Lipinski's rule of 5
using Autodock4.2. 4-hydroxypanduratin A was found interacting with target hydrophilic domain in NS2B protein by two Hbonds
(Gly80 and Asp81) with active residues, several hydrophobic interactions, Log P value of 5.6, inhibition constant (Ki) of
51.07nM and lowest binding energy of -9.95Kcal/Mol. Hence, 4-hydroxypanduratin A targeted to Site 2 will have sufficient
profound effect to inhibit protease activity to abrogate viral replication. It could be a promising potential drug candidate for JEV
infections using NS2B Site 2 as a Drug target.
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Affiliation(s)
- Chandrabhan Seniya
- Department of Biotechnology, Madhav Institute of Technology and Science, Race Course Road, Gola Ka Mandir, Gwalior (M.P.) India
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Kang C, Gayen S, Wang W, Severin R, Chen AS, Lim HA, Chia CSB, Schüller A, Doan DNP, Poulsen A, Hill J, Vasudevan SG, Keller TH. Exploring the binding of peptidic West Nile virus NS2B-NS3 protease inhibitors by NMR. Antiviral Res 2012; 97:137-44. [PMID: 23211132 DOI: 10.1016/j.antiviral.2012.11.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 11/23/2012] [Accepted: 11/24/2012] [Indexed: 11/26/2022]
Abstract
West Nile virus (WNV) NS2B-NS3 protease is an important drug target since it is an essential protein for the replication of the virus. In order to determine the minimum pharmacophore for protease inhibition, a series of dipeptide aldehydes were synthesized. The 50% inhibitory concentration (IC(50)) measurements revealed that a simple acetyl-KR-aldehyde was only threefold less active than 4-phenyl-phenylacetyl-KKR-aldehyde (1) (Stoermer et al., 2008) that was used as the reference compound. The ligand efficiency of 0.40 kcal/mol/HA (HA=heavy atom) for acetyl-KR-aldehyde is much improved compared to the reference compound 1 (0.23 kcal/mol/HA). The binding of the inhibitors was examined using (1)H-(15)N-HSQC experiments and differential chemical shifts were used to map the ligand binding sites. The biophysical studies show that the conformational mobility of WNV protease has a major impact on the design of novel inhibitors, since the protein conformation changes profoundly depending on the structure of the bound ligand.
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Affiliation(s)
- CongBao Kang
- Experimental Therapeutics Center, Nanos, Singapore, Singapore
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Doan DNP, Li KQ, Basavannacharya C, Vasudevan SG, Madhusudhan MS. Transplantation of a hydrogen bonding network from West Nile virus protease onto Dengue-2 protease improves catalytic efficiency and sheds light on substrate specificity. Protein Eng Des Sel 2012; 25:843-50. [DOI: 10.1093/protein/gzs049] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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West Nile Virus (WNV) protease and membrane interactions revealed by NMR spectroscopy. Biochem Biophys Res Commun 2012; 423:799-804. [PMID: 22713461 DOI: 10.1016/j.bbrc.2012.06.043] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 06/09/2012] [Indexed: 01/04/2023]
Abstract
West Nile Virus (WNV) protease is a two-component protease, important for the maturation of virus by cleaving the viral ploypeptide into functional proteins. WNV protease contains a Nonstructural (NS) protein 3 possessing the protease active sites and is regulated by a cofactor region containing approximately 40 amino acids from an integral membrane protein, NS2B. Although NS2B was demonstrated to be important for the location of the protease on the membrane, there was no direct evidence to show the interaction between protease (NS3) and membrane. Herein, we investigated the interaction between WNV protease and dodecylphosphocoline (DPC) micelles using NMR spectroscopy. The results showed that amino acids (31-33) from NS3 were important for the interaction with detergent micelles, which was similar to the finding in the study of protease from Dengue virus. This region may serve as an anchoring site to stabilized NS3 protease domain on the membrane.
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Martín-Acebes MA, Saiz JC. West Nile virus: A re-emerging pathogen revisited. World J Virol 2012; 1:51-70. [PMID: 24175211 PMCID: PMC3782267 DOI: 10.5501/wjv.v1.i2.51] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 02/16/2012] [Accepted: 03/05/2012] [Indexed: 02/05/2023] Open
Abstract
West Nile virus (WNV), a flavivirus of the Flaviviridae family, is maintained in nature in an enzootic transmission cycle between avian hosts and ornithophilic mosquito vectors, although the virus occasionally infects other vertebrates. WNV causes sporadic disease outbreaks in horses and humans, which may result in febrile illness, meningitis, encephalitis and flaccid paralysis. Until recently, its medical and veterinary health concern was relatively low; however, the number, frequency and severity of outbreaks with neurological consequences in humans and horses have lately increased in Europe and the Mediterranean basin. Since its introduction in the Americas, the virus spread across the continent with worrisome consequences in bird mortality and a considerable number of outbreaks among humans and horses, which have resulted in the largest epidemics of neuroinvasive WNV disease ever documented. Surprisingly, its incidence in human and animal health is very different in Central and South America, and the reasons for it are not yet understood. Even though great advances have been obtained lately regarding WNV infection, and although efficient equine vaccines are available, no specific treatments or vaccines for human use are on the market. This review updates the most recent investigations in different aspects of WNV life cycle: molecular virology, transmission dynamics, host range, clinical presentations, epidemiology, ecology, diagnosis, control, and prevention, and highlights some aspects that certainly require further research.
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Affiliation(s)
- Miguel A Martín-Acebes
- Miguel A Martín-Acebes, Juan-Carlos Saiz, Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, 28040 Madrid, Spain
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Choksupmanee O, Hodge K, Katzenmeier G, Chimnaronk S. Structural Platform for the Autolytic Activity of an Intact NS2B–NS3 Protease Complex from Dengue Virus. Biochemistry 2012; 51:2840-51. [DOI: 10.1021/bi2018267] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Opas Choksupmanee
- Institute
of Molecular Biosciences, Mahidol University, Salaya Campus, Phutthamonthon, Thailand
73170
| | - Kenneth Hodge
- Institute
of Molecular Biosciences, Mahidol University, Salaya Campus, Phutthamonthon, Thailand
73170
| | - Gerd Katzenmeier
- Institute
of Molecular Biosciences, Mahidol University, Salaya Campus, Phutthamonthon, Thailand
73170
| | - Sarin Chimnaronk
- Institute
of Molecular Biosciences, Mahidol University, Salaya Campus, Phutthamonthon, Thailand
73170
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Abstract
Dengue is a mosquito-borne viral hemorrhagic disease that is a major threat to human health in tropical and subtropical regions. Here we report crystal structures of a peptide covalently bound to dengue virus serotype 3 (DENV-3) protease as well as the serine-protease inhibitor aprotinin bound to the same enzyme. These structures reveal, for the first time, a catalytically active, closed conformation of the DENV protease. In the presence of the peptide, the DENV-3 protease forms the closed conformation in which the hydrophilic β-hairpin region of NS2B wraps around the NS3 protease core, in a manner analogous to the structure of West Nile virus (WNV) protease. Our results confirm that flavivirus proteases form the closed conformation during proteolysis, as previously proposed for WNV. The current DENV-3 protease structures reveal the detailed interactions at the P4' to P3 sites of the substrate. The new structural information explains the sequence preference, particularly for long basic residues in the nonprime side, as well as the difference in substrate specificity between the WNV and DENV proteases at the prime side. Structural analysis of the DENV-3 protease-peptide complex revealed a pocket that is formed by residues from NS2B and NS3; this pocket also exists in the WNV NS2B/NS3 protease structure and could be targeted for potential antivirus development. The structural information presented in the current study is invaluable for the design of specific inhibitors of DENV protease.
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Abstract
BACKGROUND Infection by mosquito-borne flaviviruses (family Flaviviridae) is increasing in prevalence worldwide. The vast global, social and economic impact due to the morbidity and mortality associated with the diseases caused by these viruses necessitates therapeutic intervention. There is currently no effective clinical treatment for any flaviviral infection. Therefore, there is a great need for the identification of novel inhibitors to target the virus life cycle. DISCUSSION In this article, we discuss structural and nonstructural viral proteins that are the focus of current target validation and drug discovery efforts. Both inhibition of essential enzymatic activities and disruption of necessary protein–protein interactions are considered. In addition, we address promising new targets for future research. CONCLUSION As our molecular and biochemical understanding of the flavivirus life cycle increases, the number of targets for antiviral therapeutic discovery grows and the possibility for novel drug discovery continues to strengthen.
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Shiryaev SA, Strongin AY. Structural and functional parameters of the flaviviral protease: a promising antiviral drug target. Future Virol 2010; 5:593-606. [PMID: 21076642 DOI: 10.2217/fvl.10.39] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Flaviviruses have a single-strand, positive-polarity RNA genome that encodes a single polyprotein. The polyprotein is comprised of seven nonstructural (NS) and three structural proteins. The N- and C-terminal parts of NS3 represent the serine protease and the RNA helicase, respectively. The cleavage of the polyprotein by the protease is required to produce the individual viral proteins, which assemble a new viral progeny. Conversely, inactivation of the protease blocks viral infection. Both the protease and the helicase are conserved among flaviviruses. As a result, NS3 is a promising drug target in flaviviral infections. This article examines the West Nile virus NS3 with an emphasis on the structural and functional parameters of the protease, the helicase and their cofactors.
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Affiliation(s)
- Sergey A Shiryaev
- Inflammatory & Infectious Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA
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41
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Salaemae W, Junaid M, Angsuthanasombat C, Katzenmeier G. Structure-guided mutagenesis of active site residues in the dengue virus two-component protease NS2B-NS3. J Biomed Sci 2010; 17:68. [PMID: 20735839 PMCID: PMC2933675 DOI: 10.1186/1423-0127-17-68] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Accepted: 08/24/2010] [Indexed: 12/13/2022] Open
Abstract
Background The dengue virus two-component protease NS2B/NS3 mediates processing of the viral polyprotein precursor and is therefore an important determinant of virus replication. The enzyme is now intensively studied with a view to the structure-based development of antiviral inhibitors. Although 3-dimensional structures have now been elucidated for a number of flaviviral proteases, enzyme-substrate interactions are characterized only to a limited extend. The high selectivity of the dengue virus protease for the polyprotein precursor offers the distinct advantage of designing inhibitors with exquisite specificity for the viral enzyme. To identify important determinants of substrate binding and catalysis in the active site of the dengue virus NS3 protease, nine residues, L115, D129, G133, T134, Y150, G151, N152, S163 and I165, located within the S1 and S2 pockets of the enzyme were targeted by alanine substitution mutagenesis and effects on enzyme activity were fluorometrically assayed. Methods Alanine substitutions were introduced by site-directed mutagenesis at residues L115, D129, G133, T134, Y150, G151, N152, S163 and I165 and recombinant proteins were purified from overexpressing E. coli. Effects of these substitutions on enzymatic activity of the NS3 protease were assayed by fluorescence release from the synthetic model substrate GRR-amc and kinetic parameters Km, kcat and kcat/Km were determined. Results Kinetic data for mutant derivatives in the active site of the dengue virus NS3 protease were essentially in agreement with a functional role of the selected residues for substrate binding and/or catalysis. Only the L115A mutant displayed activity comparable to the wild-type enzyme, whereas mutation of residues Y150 and G151 to alanine completely abrogated enzyme activity. A G133A mutant had an approximately 10-fold reduced catalytic efficiency thus suggesting a critical role for this residue seemingly as part of the oxyanion binding hole. Conclusions Kinetic data obtained for mutants in the NS3 protease have confirmed predictions for the conformation of the active site S1 and S2 pockets based on earlier observations. The data presented herein will be useful to further explore structure-activity relationships of the flaviviral proteases important for the structure-guided design of novel antiviral therapeutics.
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Affiliation(s)
- Wanisa Salaemae
- Laboratory of Molecular Virology, Institute of Molecular Biosciences, Mahidol University, Phutthamonthon 4 Rd, Nakornpathom 73170, Thailand
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Condotta SA, Martin MM, Boutin M, Jean F. Detection and in-cell selectivity profiling of the full-length West Nile virus NS2B/NS3 serine protease using membrane-anchored fluorescent substrates. Biol Chem 2010; 391:549-59. [PMID: 20302513 DOI: 10.1515/bc.2010.051] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Flaviviral NS2B/NS3 heterocomplex serine proteases are a primary target for anti-flavivirus drug discovery. To gain insights into the enzymatic properties and molecular determinants of flaviviral NS2B/NS3 protease substrate specificity in host cells, we developed and applied a novel series of membrane-anchored red-shifted fluorescent protein substrates to detect West Nile virus (WNV) NS2B/NS3 endoproteolytic activity in human cells. The substrate consists of a fluorescent reporter group (DsRed) tethered to the endoplasmic reticulum membrane by a membrane-anchoring domain. Between the two domains is a specific peptide linker that corresponds to the NS2A/NS2B, NS2B/NS3, NS3/NS4A, and NS4B/NS5 protein junctions within the WNV polyprotein precursor. When the protease cleaves the peptide linker, the DsRed reporter group is released, changing its localization in the cell from membrane-bound punctate perinuclear to diffuse cytoplasmic. This change in protein location can be monitored by fluorescent microscopy, and cleavage products can be quantified by Western blotting. Our data demonstrate the robustness of our trans-cleavage fluorescence assay to capture single-cell imaging of membrane-associated WNV NS2B/NS3 endoproteolytic activity and to perform in-cell selectivity profiling of the NS2B/NS3 protease. Our study is the first to provide cellular insights into the biological and enzymatic properties of a prime target for inhibitors of WNV replication.
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Affiliation(s)
- Stephanie A Condotta
- Department of Microbiology and Immunology, Life Sciences Center, the University of British Columbia, Vancouver, Canada
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Wichapong K, Pianwanit S, Sippl W, Kokpol S. Homology modeling and molecular dynamics simulations of Dengue virus NS2B/NS3 protease: insight into molecular interaction. J Mol Recognit 2010; 23:283-300. [PMID: 19693793 DOI: 10.1002/jmr.977] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The pathogenic West Nile virus (WNV) and Dengue virus (DV) are growing global threats for which there are no specific treatments. Both viruses possess a two component NS2B/NS3 protease which cleaves viral precursor proteins. Whereas for the WNV protease two crystal structures in complex with an inhibitor have been solved recently, no such information is available for the DV protease. Here, we report the generation of a homology model of DV NS2B/NS3 protease. Since it is known from the related WNV protease that it adopts a distinct conformation in free and in inhibitor-complexed form, a special emphasis was given to the analysis of the protease flexibility. Therefore, several models of DV NS2B/NS3 protease complexed with the peptidic inhibitor (Bz-Nle(P4)-Lys(P3)-Arg(P2)-Arg(P1)-H) were generated. The first DV protease model (DV-1) was constructed using the available crystal structure of the apo DV NS2B/NS3 protease. The second model (DV-2) was built taking the WNV NS3/NS2B protease in the inhibitor-complexed form as the template structure. Molecular dynamics simulations which were carried out for the WNV crystal structures as well as for the DV models provided an understanding of the role of NS2B for maintaining the protease in the active conformation. It was also demonstrated that NS2B is not only important for maintaining NS3 in the active form, but is also essential for establishing the interaction between residues from the S2 pocket and the peptidic inhibitor. The DV NS2B/NS3 model in the productive conformation can now be used for structure-based design purposes.
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Affiliation(s)
- Kanin Wichapong
- Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
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Isolation and characterization of selective and potent human Fab inhibitors directed to the active-site region of the two-component NS2B-NS3 proteinase of West Nile virus. Biochem J 2010; 427:369-76. [PMID: 20156198 DOI: 10.1042/bj20100074] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
There is a need to develop inhibitors of mosquito-borne flaviviruses, including WNV (West Nile virus). In the present paper, we describe a novel and efficient recombinant-antibody technology that led us to the isolation of inhibitory high-affinity human antibodies to the active-site region of a viral proteinase. As a proof-of-principal, we have successfully used this technology and the synthetic naive human combinatorial antibody library HuCAL GOLD(R) to isolate selective and potent function-blocking active-site-targeting antibodies to the two-component WNV NS (non-structural protein) 2B-NS3 serine proteinase, the only proteinase encoded by the flaviviral genome. First, we used the wild-type enzyme in antibody screens. Next, the positive antibody clones were counter-screened using an NS2B-NS3 mutant with a single mutation of the catalytically essential active-site histidine residue. The specificity of the antibodies to the active site was confirmed by substrate-cleavage reactions and also by using proteinase mutants with additional single amino-acid substitutions in the active-site region. The selected WNV antibodies did not recognize the structurally similar viral proteinases from Dengue virus type 2 and hepatitis C virus, and human serine proteinases. Because of their high selectivity and affinity, the identified human antibodies are attractive reagents for both further mutagenesis and structure-based optimization and, in addition, for studies of NS2B-NS3 activity. Conceptually, it is likely that the generic technology reported in the present paper will be useful for the generation of active-site-specific antibody probes for multiple enzymes.
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Su XC, Ozawa K, Qi R, Vasudevan SG, Lim SP, Otting G. NMR analysis of the dynamic exchange of the NS2B cofactor between open and closed conformations of the West Nile virus NS2B-NS3 protease. PLoS Negl Trop Dis 2009; 3:e561. [PMID: 19997625 PMCID: PMC2780355 DOI: 10.1371/journal.pntd.0000561] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Accepted: 10/30/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The two-component NS2B-NS3 proteases of West Nile and dengue viruses are essential for viral replication and established targets for drug development. In all crystal structures of the proteases to date, the NS2B cofactor is located far from the substrate binding site (open conformation) in the absence of inhibitor and lining the substrate binding site (closed conformation) in the presence of an inhibitor. METHODS In this work, nuclear magnetic resonance (NMR) spectroscopy of isotope and spin-labeled samples of the West Nile virus protease was used to investigate the occurrence of equilibria between open and closed conformations in solution. FINDINGS In solution, the closed form of the West Nile virus protease is the predominant conformation irrespective of the presence or absence of inhibitors. Nonetheless, dissociation of the C-terminal part of the NS2B cofactor from the NS3 protease (open conformation) occurs in both the presence and the absence of inhibitors. Low-molecular-weight inhibitors can shift the conformational exchange equilibria so that over 90% of the West Nile virus protease molecules assume the closed conformation. The West Nile virus protease differs from the dengue virus protease, where the open conformation is the predominant form in the absence of inhibitors. CONCLUSION Partial dissociation of NS2B from NS3 has implications for the way in which the NS3 protease can be positioned with respect to the host cell membrane when NS2B is membrane associated via N- and C-terminal segments present in the polyprotein. In the case of the West Nile virus protease, discovery of low-molecular-weight inhibitors that act by breaking the association of the NS2B cofactor with the NS3 protease is impeded by the natural affinity of the cofactor to the NS3 protease. The same strategy can be more successful in the case of the dengue virus NS2B-NS3 protease.
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Affiliation(s)
- Xun-Cheng Su
- Australian National University, Research School of Chemistry, Canberra, Australia
| | - Kiyoshi Ozawa
- Australian National University, Research School of Chemistry, Canberra, Australia
| | - Ruhu Qi
- Australian National University, Research School of Chemistry, Canberra, Australia
| | | | - Siew P. Lim
- Novartis Institute for Tropical Diseases, Chromos, Singapore
| | - Gottfried Otting
- Australian National University, Research School of Chemistry, Canberra, Australia
- * E-mail:
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Su XC, Ozawa K, Yagi H, Lim SP, Wen D, Ekonomiuk D, Huang D, Keller TH, Sonntag S, Caflisch A, Vasudevan SG, Otting G. NMR study of complexes between low molecular mass inhibitors and the West Nile virus NS2B-NS3 protease. FEBS J 2009; 276:4244-55. [PMID: 19583774 DOI: 10.1111/j.1742-4658.2009.07132.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The two-component NS2B-NS3 protease of West Nile virus is essential for its replication and presents an attractive target for drug development. Here, we describe protocols for the high-yield expression of stable isotope-labelled samples in vivo and in vitro. We also describe the use of NMR spectroscopy to determine the binding mode of new low molecular mass inhibitors of the West Nile virus NS2B-NS3 protease which were discovered using high-throughput in vitro screening. Binding to the substrate-binding sites S1 and S3 is confirmed by intermolecular NOEs and comparison with the binding mode of a previously identified low molecular mass inhibitor. Our results show that all these inhibitors act by occupying the substrate-binding site of the protease rather than by an allosteric mechanism. In addition, the NS2B polypeptide chain was found to be positioned near the substrate-binding site, as observed previously in crystal structures of the protease in complex with peptide inhibitors or bovine pancreatic trypsin inhibitor. This indicates that the new low molecular mass compounds, although inhibiting the protease, also promote the proteolytically active conformation of NS2B, which is very different from the crystal structure of the protein without inhibitor.
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Affiliation(s)
- Xun-Cheng Su
- Research School of Chemistry, Australian National University, Canberra, Australia
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