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Deng J, Gong F, Li Y, Tan X, Liu X, Yang S, Chen X, Wang H, Liu Q, Shen C, Zhou L, Chen Y. Structural and functional insights into the 2'-O-methyltransferase of SARS-CoV-2. Virol Sin 2024; 39:619-631. [PMID: 38969340 DOI: 10.1016/j.virs.2024.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 07/02/2024] [Indexed: 07/07/2024] Open
Abstract
A unique feature of coronaviruses is their utilization of self-encoded nonstructural protein 16 (nsp16), 2'-O-methyltransferase (2'-O-MTase), to cap their RNAs through ribose 2'-O-methylation modification. This process is crucial for maintaining viral genome stability, facilitating efficient translation, and enabling immune escape. Despite considerable advances in the ultrastructure of SARS-CoV-2 nsp16/nsp10, insights into its molecular mechanism have so far been limited. In this study, we systematically characterized the 2'-O-MTase activity of nsp16 in SARS-CoV-2, focusing on its dependence on nsp10 stimulation. We observed cross-reactivity between nsp16 and nsp10 in various coronaviruses due to a conserved interaction interface. However, a single residue substitution (K58T) in SARS-CoV-2 nsp10 restricted the functional activation of MERS-CoV nsp16. Furthermore, the cofactor nsp10 effectively enhanced the binding of nsp16 to the substrate RNA and the methyl donor S-adenosyl-l-methionine (SAM). Mechanistically, His-80, Lys-93, and Gly-94 of nsp10 interacted with Asp-102, Ser-105, and Asp-106 of nsp16, respectively, thereby effectively stabilizing the SAM binding pocket. Lys-43 of nsp10 interacted with Lys-38 and Gly-39 of nsp16 to dynamically regulate the RNA binding pocket and facilitate precise binding of RNA to the nsp16/nsp10 complex. By assessing the conformational epitopes of nsp16/nsp10 complex, we further determined the critical residues involved in 2'-O-MTase activity. Additionally, we utilized an in vitro biochemical platform to screen potential inhibitors targeting 2'-O-MTase activity. Overall, our results significantly enhance the understanding of viral 2'-O methylation process and mechanism, providing valuable targets for antiviral drug development.
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Affiliation(s)
- Jikai Deng
- State Key Laboratory of Virology, RNA Institute, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, 430072, China
| | - Feiyu Gong
- State Key Laboratory of Virology, RNA Institute, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, 430072, China
| | - Yingjian Li
- State Key Laboratory of Virology, RNA Institute, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, 430072, China
| | - Xue Tan
- State Key Laboratory of Virology, RNA Institute, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, 430072, China
| | - Xuemei Liu
- State Key Laboratory of Virology, RNA Institute, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, 430072, China
| | - Shimin Yang
- State Key Laboratory of Virology, RNA Institute, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, 430072, China
| | - Xianying Chen
- State Key Laboratory of Virology, RNA Institute, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, 430072, China
| | - Hongyun Wang
- State Key Laboratory of Virology, RNA Institute, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, 430072, China
| | - Qianyun Liu
- State Key Laboratory of Virology, RNA Institute, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, 430072, China
| | - Chao Shen
- State Key Laboratory of Virology, RNA Institute, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, 430072, China
| | - Li Zhou
- State Key Laboratory of Virology, RNA Institute, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, 430072, China; Animal Bio-Safety Level III Laboratory/Institute for Vaccine Research, Wuhan University School of Medicine, Wuhan, 430071, China
| | - Yu Chen
- State Key Laboratory of Virology, RNA Institute, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, 430072, China; Animal Bio-Safety Level III Laboratory/Institute for Vaccine Research, Wuhan University School of Medicine, Wuhan, 430071, China.
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2
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Akram M, Hameed S, Hassan A, Khan KM. Development in the Inhibition of Dengue Proteases as Drug Targets. Curr Med Chem 2024; 31:2195-2233. [PMID: 37723635 DOI: 10.2174/0929867331666230918110144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 06/24/2023] [Accepted: 08/04/2023] [Indexed: 09/20/2023]
Abstract
BACKGROUND Viral infections continue to increase morbidity and mortality severely. The flavivirus genus has fifty different species, including the dengue, Zika, and West Nile viruses that can infect 40% of individuals globally, who reside in at least a hundred different countries. Dengue, one of the oldest and most dangerous human infections, was initially documented by the Chinese Medical Encyclopedia in the Jin period. It was referred to as "water poison," connected to flying insects, i.e., Aedes aegypti and Aedes albopictus. DENV causes some medical expressions like dengue hemorrhagic fever, acute febrile illness, and dengue shock syndrome. OBJECTIVE According to the World Health Organization report of 2012, 2500 million people are in danger of contracting dengue fever worldwide. According to a recent study, 96 million of the 390 million dengue infections yearly show some clinical or subclinical severity. There is no antiviral drug or vaccine to treat this severe infection. It can be controlled by getting enough rest, drinking plenty of water, and using painkillers. The first dengue vaccine created by Sanofi, called Dengvaxia, was previously approved by the USFDA in 2019. All four serotypes of the DENV1-4 have shown re-infection in vaccine recipients. However, the usage of Dengvaxia has been constrained by its adverse effects. CONCLUSION Different classes of compounds have been reported against DENV, such as nitrogen-containing heterocycles (i.e., imidazole, pyridine, triazoles quinazolines, quinoline, and indole), oxygen-containing heterocycles (i.e., coumarins), and some are mixed heterocyclic compounds of S, N (thiazole, benzothiazine, and thiazolidinediones), and N, O (i.e., oxadiazole). There have been reports of computationally designed compounds to impede the molecular functions of specific structural and non-structural proteins as potential therapeutic targets. This review summarized the current progress in developing dengue protease inhibitors.
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Affiliation(s)
- Muhammad Akram
- Department of Chemistry, Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | - Shehryar Hameed
- H.E.J. Research Institute of Chemistry, International Centre for Chemical and Biological Sciences, University of Karachi, Karachi, 75720, Pakistan
| | - Abbas Hassan
- Department of Chemistry, Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | - Khalid Mohammed Khan
- H.E.J. Research Institute of Chemistry, International Centre for Chemical and Biological Sciences, University of Karachi, Karachi, 75720, Pakistan
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Chen H, Lin S, Yang F, Chen Z, Guo L, Yang J, Lin X, Wang L, Duan Y, Wen A, Zhang X, Dai Y, Yin K, Yuan X, Yu C, He Y, He B, Cao Y, Dong H, Li J, Zhao Q, Liu Q, Lu G. Structural and functional basis of low-affinity SAM/SAH-binding in the conserved MTase of the multi-segmented Alongshan virus distantly related to canonical unsegmented flaviviruses. PLoS Pathog 2023; 19:e1011694. [PMID: 37831643 PMCID: PMC10575543 DOI: 10.1371/journal.ppat.1011694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 09/18/2023] [Indexed: 10/15/2023] Open
Abstract
Alongshan virus (ALSV), a newly discovered member of unclassified Flaviviridae family, is able to infect humans. ALSV has a multi-segmented genome organization and is evolutionarily distant from canonical mono-segmented flaviviruses. The virus-encoded methyltransferase (MTase) plays an important role in viral replication. Here we show that ALSV MTase readily binds S-adenosyl-L-methionine (SAM) and S-adenosyl-L-homocysteine (SAH) but exhibits significantly lower affinities than canonical flaviviral MTases. Structures of ALSV MTase in the free and SAM/SAH-bound forms reveal that the viral enzyme possesses a unique loop-element lining side-wall of the SAM/SAH-binding pocket. While the equivalent loop in flaviviral MTases half-covers SAM/SAH, contributing multiple hydrogen-bond interactions; the pocket-lining loop of ALSV MTase is of short-length and high-flexibility, devoid of any physical contacts with SAM/SAH. Subsequent mutagenesis data further corroborate such structural difference affecting SAM/SAH-binding. Finally, we also report the structure of ALSV MTase bound with sinefungin, an SAM-analogue MTase inhibitor. These data have delineated the basis for the low-affinity interaction between ALSV MTase and SAM/SAH and should inform on antiviral drug design.
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Affiliation(s)
- Hua Chen
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Daping Hospital, Army Medical University, Chongqing, China
| | - Sheng Lin
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Fanli Yang
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Zimin Chen
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Liyan Guo
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Jing Yang
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Xi Lin
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Lingling Wang
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yanping Duan
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Ao Wen
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Xindan Zhang
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yushan Dai
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Keqing Yin
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Xin Yuan
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Chongzhang Yu
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yarong He
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Bin He
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yu Cao
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- Disaster Medicine Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Haohao Dong
- State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Jian Li
- School of Basic Medical Sciences, Chengdu University, Chengdu, Sichuan, China
| | - Qi Zhao
- College of Food and Biological Engineering, Chengdu University, Chengdu, Sichuan, China
| | - Quan Liu
- Center of Infectious diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, State Key Laboratory of Zoonotic Diseases, Changchun, Jilin, China
| | - Guangwen Lu
- Department of Emergency Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
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4
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Samrat SK, Bashir Q, Huang Y, Trieshmann CW, Tharappel AM, Zhang R, Chen K, Geoge Zheng Y, Li Z, Li H. Broad-Spectrum Small-Molecule Inhibitors Targeting the SAM-Binding Site of Flavivirus NS5 Methyltransferase. ACS Infect Dis 2023; 9:1319-1333. [PMID: 37348028 PMCID: PMC10436986 DOI: 10.1021/acsinfecdis.2c00571] [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: 06/24/2023]
Abstract
Flavivirus infections, such as those caused by dengue virus (DENV), West Nile virus (WNV), yellow fever virus (YFV), and Zika virus (ZIKV), pose a rising threat to global health. There are no FDA-approved drugs for flaviviruses, although a small number of flaviviruses have vaccines. For flaviviruses or unknown viruses that may appear in the future, it is particularly desirable to identify broad-spectrum inhibitors. The NS5 protein is regarded as one of the most promising flavivirus drug targets because it is conserved across flaviviruses. In this study, we used FL-NAH, a fluorescent analog of the methyl donor S-adenosyl methionine (SAM), to develop a fluorescence polarization (FP)-based high throughput screening (HTS) assay to specifically target methyltransferase (MTase), a vital enzyme for flaviviruses that methylates the N7 and 2'-O positions of the viral 5'-RNA cap. Pilot screening identified two candidate MTase inhibitors, NSC 111552 and 288387. The two compounds inhibited the FL-NAH binding to the DENV3 MTase with low micromolar IC50. Functional assays verified the inhibitory potency of these molecules for the flavivirus MTase activity. Binding studies indicated that these molecules are bound directly to the DENV3 MTase with similar low micromolar affinity. Furthermore, we showed that these compounds greatly reduced ZIKV replication in cell-based experiments at dosages that did not cause cytotoxicity. Finally, docking studies revealed that these molecules bind to the SAM-binding region on the DENV3 MTase, and further mutagenesis studies verified residues important for the binding of these compounds. Overall, these compounds are innovative and attractive candidates for the development of broad-spectrum inhibitors for the treatment of flavivirus infections.
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Affiliation(s)
- Subodh Kumar Samrat
- Department of Pharmacology and Toxicology, R Ken Coit College of Pharmacy, The University of Arizona, 1703 E Mabel St, Tucson AZ, 85721-0207, USA
| | - Qamar Bashir
- Department of Pharmacology and Toxicology, R Ken Coit College of Pharmacy, The University of Arizona, 1703 E Mabel St, Tucson AZ, 85721-0207, USA
| | - Yiding Huang
- Department of Pharmacology and Toxicology, R Ken Coit College of Pharmacy, The University of Arizona, 1703 E Mabel St, Tucson AZ, 85721-0207, USA
| | - Carl William Trieshmann
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia, 30602, USA
| | - Anil Mathew Tharappel
- Department of Pharmacology and Toxicology, R Ken Coit College of Pharmacy, The University of Arizona, 1703 E Mabel St, Tucson AZ, 85721-0207, USA
| | - Ran Zhang
- Department of Pharmacology and Toxicology, R Ken Coit College of Pharmacy, The University of Arizona, 1703 E Mabel St, Tucson AZ, 85721-0207, USA
| | - Ke Chen
- Department of Pharmacology and Toxicology, R Ken Coit College of Pharmacy, The University of Arizona, 1703 E Mabel St, Tucson AZ, 85721-0207, USA
| | - Y. Geoge Zheng
- Department of Pharmacology and Toxicology, R Ken Coit College of Pharmacy, The University of Arizona, 1703 E Mabel St, Tucson AZ, 85721-0207, USA
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia, 30602, USA
| | - Zhong Li
- Department of Pharmacology and Toxicology, R Ken Coit College of Pharmacy, The University of Arizona, 1703 E Mabel St, Tucson AZ, 85721-0207, USA
| | - Hongmin Li
- Department of Pharmacology and Toxicology, R Ken Coit College of Pharmacy, The University of Arizona, 1703 E Mabel St, Tucson AZ, 85721-0207, USA
- Department of Chemistry and Biochemistry, College of Science & College of Medicine, The University of Arizona, Tucson AZ, 85721, USA
- The BIO5 Institute, The University of Arizona, Tucson, AZ 85721, USA
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5
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Abstract
The positive-sense flavivirus RNA genome bears a cap 1 structure essential for RNA stability and viral protein translation, and the formation of cap 1 requires the virally encoded nonstructural protein NS5 harboring guanylyltransferase (GTase), cap guanine N7 methyltransferase (N7 MTase), and 5'-nucleotide ribose 2'-O MTase activities in its single-domain MTase module. Despite numerous MTase-containing structures reported, the structural evidence for a critical GMP-enzyme intermediate formation and RNA repositioning when transitioning among different reactions is missing. Here, we report 10 high-resolution MTase crystal structures of Omsk hemorrhagic fever virus (OHFV), a representative high-consequence tick-borne flavivirus, capturing previously unidentified GMP-arginine adduct structures and a rarely observed capped RNA conformation. These structures help us thread capping events in the canonical model with a structure-based hypothesis involving the flipping of the 5' nucleotide, while the observation of an m7GMP-arginine adduct is compatible with an alternate capping model that decouples the N7 and 2'-O methylation steps. IMPORTANCE The methyltransferase (MTase) domain of flavivirus NS5 is unique in harboring guanylyltransferase (GTase), N7 MTase, and 2'-O MTase activities, playing a central role in viral RNA capping. However, the detailed mechanisms of the multistep capping process remain elusive. Here, we report 10 crystal structures of a flavivirus MTase to help understand the guanylyl transfer from GTP to the GTase itself and the transition between guanylyl transfer and methylation steps. In particular, a previously unobserved GMP-arginine covalent intermediate was captured multiple times in MTase crystal soaking trials with GTP present in the soaking solution, supporting its role in bridging the guanylyl transfer from GTP to the GTase and subsequent transfer to the 5'-diphosphate RNA.
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Current Trends and Limitations in Dengue Antiviral Research. Trop Med Infect Dis 2021; 6:tropicalmed6040180. [PMID: 34698303 PMCID: PMC8544673 DOI: 10.3390/tropicalmed6040180] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/22/2021] [Accepted: 09/24/2021] [Indexed: 12/13/2022] Open
Abstract
Dengue is the most prevalent arthropod-borne viral disease worldwide and affects approximately 2.5 billion people living in over 100 countries. Increasing geographic expansion of Aedes aegypti mosquitoes (which transmit the virus) has made dengue a global health concern. There are currently no approved antivirals available to treat dengue, and the only approved vaccine used in some countries is limited to seropositive patients. Treatment of dengue, therefore, remains largely supportive to date; hence, research efforts are being intensified for the development of antivirals. The nonstructural proteins, 3 and 5 (NS3 and NS5), have been the major targets for dengue antiviral development due to their indispensable enzymatic and biological functions in the viral replication process. NS5 is the largest and most conserved nonstructural protein encoded by flaviviruses. Its multifunctionality makes it an attractive target for antiviral development, but research efforts have, this far, not resulted in the successful development of an antiviral targeting NS5. Increase in structural insights into the dengue NS5 protein will accelerate drug discovery efforts focused on NS5 as an antiviral target. In this review, we will give an overview of the current state of therapeutic development, with a focus on NS5 as a therapeutic target against dengue.
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Fernandes PO, Chagas MA, Rocha WR, Moraes AH. Non-structural protein 5 (NS5) as a target for antiviral development against established and emergent flaviviruses. Curr Opin Virol 2021; 50:30-39. [PMID: 34340199 DOI: 10.1016/j.coviro.2021.07.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 06/18/2021] [Accepted: 07/02/2021] [Indexed: 11/19/2022]
Abstract
Flaviviruses are among the most critical pathogens in tropical regions and cause a growing number of severe diseases in developing countries. The development of antiviral therapeutics is crucial for managing flavivirus outbreaks. Among the ten proteins encoded in the flavivirus RNA, non-structural protein 5, NS5, is a promising drug target. NS5 plays a fundamental role in flavivirus replication, viral RNA methylation, RNA polymerization, and host immune system evasion. Most of the NS5 inhibitor candidates target NS5 active sites. However, the similarity of NS5 activity sites with human enzymes can cause side effects. Identifying new allosteric sites in NS5 can contribute enormously to antiviral development. The NS5 structural characterization enabled exploring new regions, such as the residues involved in MTase-RdRp interaction, NS5 oligomerization, and NS5 interaction with other viral and host-cell proteins. Targeting NS5 critical interactions might lead to new compounds and overcomes the toxicity of current NS5-inhibitor candidates.
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Affiliation(s)
- Philipe O Fernandes
- Departamento de Produtos Farmacêuticos, Faculdade de Farmácia, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Brazil
| | - Marcelo A Chagas
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Brazil
| | - Willian R Rocha
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Brazil
| | - Adolfo H Moraes
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Brazil; Department of NMR-based Structural Biology, Max-Planck Institute for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany.
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8
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Mariasina SS, Chang CF, Petrova OA, Efimov SV, Klochkov VV, Kechko OI, Mitkevich VA, Sergiev PV, Dontsova OA, Polshakov VI. Williams-Beuren syndrome-related methyltransferase WBSCR27: cofactor binding and cleavage. FEBS J 2020; 287:5375-5393. [PMID: 32255258 DOI: 10.1111/febs.15320] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 02/20/2020] [Accepted: 03/30/2020] [Indexed: 11/28/2022]
Abstract
Williams-Beuren syndrome, characterized by numerous physiological and mental problems, is caused by the heterozygous deletion of chromosome region 7q11.23, which results in the disappearance of 26 protein-coding genes. Protein WBSCR27 is a product of one of these genes whose biological function has not yet been established and for which structural information has been absent until now. Using NMR, we investigated the structural and functional properties of murine WBSCR27. For protein in the apo form and in a complex with S-(5'-adenosyl)-l-homocysteine (SAH), a complete NMR resonance assignment has been obtained and the secondary structure has been determined. This information allows us to attribute WBSCR27 to Class I methyltransferases. The interaction of WBSCR27 with the cofactor S-(5'-adenosyl)-l-methionine (SAM) and its metabolic products - SAH, 5'-deoxy-5'-methylthioadenosine (MTA) and 5'-deoxyadenosine (5'dAdo) - was studied by NMR and isothermal titration calorimetry. SAH binds WBSCR27 much tighter than SAM, leaving open the question of cofactor turnover in the methylation reaction. One possible answer to this question is the presence of weak but detectable nucleosidase activity for WBSCR27. We found that the enzyme catalyses the cleavage of the adenine moiety from SAH, MTA and 5'dAdo, similar to the action of bacterial SAH/MTA nucleosidases. We also found that the binding of SAM or SAH causes a significant change in the structure of WBSCR27 and in the conformational mobility of the protein fragments, which can be attributed to the substrate recognition site. This indicates that the binding of the cofactor modulates the folding of the substrate-recognizing region of the enzyme.
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Affiliation(s)
| | - Chi-Fon Chang
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | | | - Sergey V Efimov
- NMR Laboratory, Institute of Physics, Kazan Federal University, Russia
| | | | - Olga I Kechko
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - Vladimir A Mitkevich
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - Petr V Sergiev
- M.V. Lomonosov Moscow State University, Russia.,Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Olga A Dontsova
- M.V. Lomonosov Moscow State University, Russia.,Skolkovo Institute of Science and Technology, Moscow, Russia
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Wennerstrand P, Blissing A, Mårtensson LG. In Vitro Protein Stability of Two Naturally Occurring Thiopurine S-Methyltransferase Variants: Biophysical Characterization of TPMT*6 and TPMT*8. ACS OMEGA 2017; 2:4991-4999. [PMID: 30023734 PMCID: PMC6044926 DOI: 10.1021/acsomega.7b00801] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 07/18/2017] [Indexed: 06/02/2023]
Abstract
Thiopurine S-methyltransferase (TPMT) is a polymorphic enzyme involved in the metabolism and inactivation of thiopurine substances administered as immunosuppressants in the treatment of malignancies and autoimmune diseases. In this study, the naturally occurring variants, TPMT*6 (Y180F) and TPMT*8 (R215H), have been biophysically characterized. Despite being classified as low and intermediate in vivo enzyme activity variants, respectively, our results demonstrate a discrepancy because both TPMT*6 and TPMT*8 were found to exhibit normal functionality in vitro. While TPMT*8 exhibited biophysical properties almost indistinguishable from those of TPMTwt, the TPMT*6 variant was found to be destabilized. Furthermore, the contributions of the cofactor S-adenosylmethionine (SAM) to the thermodynamic stability of TPMT were investigated, but only a modest stabilizing effect was observed. Also presented herein is a new method for studies of the biophysical characteristics of TPMT and its variants using the extrinsic fluorescent probe 8-anilinonaphthalene-1-sulfonic acid (ANS). ANS was found to bind strongly to all investigated TPMT variants with a Kd of approximately 0.2 μM and a 1:1 binding ratio as determined by isothermal titration calorimetry (ITC). Circular dichroism and fluorescence measurements showed that ANS binds exclusively to the native state of TPMT, and binding to the active site was confirmed by molecular modeling and simulated docking as well as ITC measurements. The strong binding of the probe to native TPMT and the conformity of the obtained results demonstrate the advantages of using ANS binding characteristics in studies of this protein and its variants.
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10
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Abstract
INTRODUCTION Flaviviruses are major causes of infectious disease. The vast global, social and economic impact due to morbidity and mortality associated with diseases caused by these viruses urgently demands effective therapeutic interventions. There is currently no specific antiviral therapy available for the effective clinical treatment of infections by any of the flaviviridae. Development of more effective vaccines and antiviral agents for the prevention and treatment of most flavivirus infections remains a clear public health priority in the 21st century. AREAS COVERED This review describes some of the recent discoveries in the field of flavivirus inhibitor development, with a particular focus on targeting viral proteins. Emphasis is placed on the advances published during the 2012-2015 period. EXPERT OPINION The field of drug discovery targeting viral proteins has progressed slowly in recent years. New information, particularly on structures, location and mechanisms of action of established protein targets have been reported. There have also been studies on repurposing known drugs as templates for targeting flavivirus proteins and these hits could be promising templates for developing new more potent inhibitors. Further research should be conducted to improve in vitro assays that better reflect the conditions found in cellular environments.
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Affiliation(s)
- W Mei Kok
- a Division of Chemistry and Structural Biology, Institute for Molecular Bioscience , The University of Queensland , Brisbane , Australia
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11
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Abstract
The dengue virus and related flaviviruses are an increasing global health threat. In this perspective, we comment on and review medicinal chemistry efforts aimed at the prevention or treatment of dengue infections. We include target-based approaches aimed at viral or host factors and results from phenotypic screenings in cellular assay systems for viral replication. This perspective is limited to the discussion of results that provide explicit chemistry or structure-activity relationship (SAR), or appear to be of particular interest to the medicinal chemist for other reasons. The discovery and development efforts discussed here may at least partially be extrapolated toward other emerging flaviviral infections, such as West Nile virus. Therefore, this perspective, although not aimed at flaviviruses in general, should also be able to provide an overview of the medicinal chemistry of these closely related infectious agents.
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Affiliation(s)
- Mira A M Behnam
- Medicinal Chemistry, Institute of Pharmacy and Molecular Biotechnology IPMB, Heidelberg University , Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
| | - Christoph Nitsche
- Medicinal Chemistry, Institute of Pharmacy and Molecular Biotechnology IPMB, Heidelberg University , Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
| | - Veaceslav Boldescu
- Medicinal Chemistry, Institute of Pharmacy and Molecular Biotechnology IPMB, Heidelberg University , Im Neuenheimer Feld 364, 69120 Heidelberg, Germany.,Laboratory of Organic Synthesis, Institute of Chemistry of the Academy of Sciences of Moldova , Academiei 3, 2028 Chisinau, Moldova
| | - Christian D Klein
- Medicinal Chemistry, Institute of Pharmacy and Molecular Biotechnology IPMB, Heidelberg University , Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
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Brecher M, Chen H, Li Z, Banavali NK, Jones SA, Zhang J, Kramer LD, Li H. Identification and Characterization of Novel Broad-Spectrum Inhibitors of the Flavivirus Methyltransferase. ACS Infect Dis 2015; 1:340-9. [PMID: 26726314 DOI: 10.1021/acsinfecdis.5b00070] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Flavivirus methyltransferase (MTase) is essential for viral replication. Here we report the identification of small molecules through virtual screening that putatively bind to the SAM-binding site of flavivirus MTase and inhibit its function. Six of these computationally predicted binders were identified to show significant MTase inhibition with low micromolar inhibitory activity. The most active compounds showed broad-spectrum activity against the MTase proteins of other flaviviruses. Two of these compounds also showed low cytotoxicity and high antiviral efficacy in cell-based assays. Competitive binding analyses indicated that the inhibitors performed their inhibitory function through competitive binding to the SAM cofactor binding site of the MTase. The crystal structure of the MTase-inhibitor complex further supports the mode of action and provides routes for their further optimization as flavivirus MTase inhibitors.
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Affiliation(s)
- Matthew Brecher
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, New York 12208, United States
| | - Hui Chen
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, New York 12208, United States
| | - Zhong Li
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, New York 12208, United States
| | - Nilesh K. Banavali
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, New York 12208, United States
- Department of Biomedical Sciences, School of Public Health, State University of New York, P.O. Box 509, Albany, New York 12201 United States
| | - Susan A. Jones
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, New York 12208, United States
| | - Jing Zhang
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, New York 12208, United States
| | - Laura D. Kramer
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, New York 12208, United States
- Department of Biomedical Sciences, School of Public Health, State University of New York, P.O. Box 509, Albany, New York 12201 United States
| | - Hongmin Li
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, New York 12208, United States
- Department of Biomedical Sciences, School of Public Health, State University of New York, P.O. Box 509, Albany, New York 12201 United States
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13
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Lim SP, Noble CG, Shi PY. The dengue virus NS5 protein as a target for drug discovery. Antiviral Res 2015; 119:57-67. [DOI: 10.1016/j.antiviral.2015.04.010] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 03/19/2015] [Accepted: 04/11/2015] [Indexed: 12/25/2022]
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14
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Vernekar SKV, Qiu L, Zhang J, Kankanala J, Li H, Geraghty RJ, Wang Z. 5'-Silylated 3'-1,2,3-triazolyl Thymidine Analogues as Inhibitors of West Nile Virus and Dengue Virus. J Med Chem 2015; 58:4016-28. [PMID: 25909386 DOI: 10.1021/acs.jmedchem.5b00327] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
West Nile virus (WNV) and Dengue virus (DENV) are important human pathogens for which there are presently no vaccine or specific antivirals. We report herein a 5'-silylated nucleoside scaffold derived from 3'-azidothymidine (AZT) consistently and selectively inhibiting WNV and DENV at low micromolar concentrations. Further synthesis of various triazole bioisosteres demonstrated clear structure-activity relationships (SARs) in which the antiviral activity against WNV and DENV hinges largely on both the 5'-silyl group and the substituent of 3'-triazole or its bioisosteres. Particularly interesting is the 5' silyl group which turns on the antiviral activity against WNV and DENV while abrogating the previously reported antiviral potency against human immunodeficiency virus (HIV-1). The antiviral activity was confirmed through a plaque assay where viral titer reduction was observed in the presence of selected compounds. Molecular modeling and competitive S-adenosyl-l-methionine (SAM) binding assay suggest that these compounds likely confer antiviral activity via binding to methyltransferase (MTase).
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Affiliation(s)
- Sanjeev Kumar V Vernekar
- †Center for Drug Design, Academic Health Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Li Qiu
- †Center for Drug Design, Academic Health Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Jing Zhang
- ‡Wadsworth Center, New York State Department of Health, 120 New Scotland Ave., Albany, New York 12208, United States
| | - Jayakanth Kankanala
- †Center for Drug Design, Academic Health Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Hongmin Li
- ‡Wadsworth Center, New York State Department of Health, 120 New Scotland Ave., Albany, New York 12208, United States.,§Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, New York 12201, United States
| | - Robert J Geraghty
- †Center for Drug Design, Academic Health Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Zhengqiang Wang
- †Center for Drug Design, Academic Health Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
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