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Eberle RJ, Olivier DS, Amaral MS, Pacca CC, Nogueira ML, Arni RK, Willbold D, Coronado MA. Riboflavin, a Potent Neuroprotective Vitamin: Focus on Flavivirus and Alphavirus Proteases. Microorganisms 2022; 10:1331. [PMID: 35889050 PMCID: PMC9315535 DOI: 10.3390/microorganisms10071331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/24/2022] [Accepted: 06/29/2022] [Indexed: 12/01/2022] Open
Abstract
Several neurotropic viruses are members of the flavivirus and alphavirus families. Infections caused by these viruses may cause long-term neurological sequelae in humans. The continuous emergence of infections caused by viruses around the world, such as the chikungunya virus (CHIKV) (Alphavirus genus), the zika virus (ZIKV) and the yellow fever virus (YFV) (both of the Flavivirus genus), warrants the development of new strategies to combat them. Our study demonstrates the inhibitory potential of the water-soluble vitamin riboflavin against NS2B/NS3pro of ZIKV and YFV and nsP2pro of CHIKV. Riboflavin presents a competitive inhibition mode with IC50 values in the medium µM range of 79.4 ± 5.0 µM for ZIKV NS2B/NS3pro and 45.7 ± 2.9 μM for YFV NS2B/NS3pro. Against CHIKV nsP2pro, the vitamin showed a very strong effect (93 ± 5.7 nM). The determined dissociation constants (KD) are significantly below the threshold value of 30 µM. The ligand binding increases the thermal stability between 4 °C and 8 °C. Unexpectedly, riboflavin showed inhibiting activity against another viral protein; the molecule was also able to inhibit the viral entry of CHIKV. Molecular dynamics simulations indicated great stability of riboflavin in the protease active site, which validates the repurposing of riboflavin as a promising molecule in drug development against the viruses presented here.
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Affiliation(s)
- Raphael J. Eberle
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany;
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße, 40225 Düsseldorf, Germany
| | - Danilo S. Olivier
- Center of Integrated Sciences, Campus Cimba, Federal University of Tocantins, Araguaína 77824-838, TO, Brazil;
| | - Marcos S. Amaral
- Institute of Physics, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil;
| | - Carolina C. Pacca
- Instituto Superior de Educação Ceres, FACERES Medical School, São José do Rio Preto 15090-305, SP, Brazil;
- Laboratório de Pesquisas em Virologia, Departamento de Doenças Dermatológicas, Infecciosas e Parasitárias, Faculdade de Medicina de São José do Rio Preto-FAMERP, São José do Rio Preto 15090-000, SP, Brazil;
| | - Mauricio L. Nogueira
- Laboratório de Pesquisas em Virologia, Departamento de Doenças Dermatológicas, Infecciosas e Parasitárias, Faculdade de Medicina de São José do Rio Preto-FAMERP, São José do Rio Preto 15090-000, SP, Brazil;
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77550, USA
| | - Raghuvir K. Arni
- Multiuser Center for Biomolecular Innovation, Department of Physics, IBILCE, São Paulo State University, São Jose do Rio Preto 15054-000, SP, Brazil;
| | - Dieter Willbold
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany;
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße, 40225 Düsseldorf, Germany
- JuStruct: Jülich Centre for Structural Biology, Forchungszentrum Jülich, 52428 Jülich, Germany
| | - Monika A. Coronado
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany;
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2
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Hulce KR, Jaishankar P, Lee GM, Bohn MF, Connelly EJ, Wucherer K, Ongpipattanakul C, Volk RF, Chuo SW, Arkin MR, Renslo AR, Craik CS. Inhibiting a dynamic viral protease by targeting a non-catalytic cysteine. Cell Chem Biol 2022; 29:785-798.e19. [PMID: 35364007 PMCID: PMC9133232 DOI: 10.1016/j.chembiol.2022.03.007] [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: 07/07/2021] [Revised: 01/07/2022] [Accepted: 03/10/2022] [Indexed: 11/03/2022]
Abstract
Viruses are responsible for some of the most deadly human diseases, yet available vaccines and antivirals address only a fraction of the potential viral human pathogens. Here, we provide a methodology for managing human herpesvirus (HHV) infection by covalently inactivating the HHV maturational protease via a conserved, non-catalytic cysteine (C161). Using human cytomegalovirus protease (HCMV Pr) as a model, we screened a library of disulfides to identify molecules that tether to C161 and inhibit proteolysis, then elaborated hits into irreversible HCMV Pr inhibitors that exhibit broad-spectrum inhibition of other HHV Pr homologs. We further developed an optimized tool compound targeted toward HCMV Pr and used an integrative structural biology and biochemical approach to demonstrate inhibitor stabilization of HCMV Pr homodimerization, exploiting a conformational equilibrium to block proteolysis. Irreversible HCMV Pr inhibition disrupts HCMV infectivity in cells, providing proof of principle for targeting proteolysis via a non-catalytic cysteine to manage viral infection.
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Affiliation(s)
- Kaitlin R Hulce
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94143-2280, USA
| | - Priyadarshini Jaishankar
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94143-2280, USA; Small Molecule Discovery Center, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94143-2280, USA
| | - Gregory M Lee
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94143-2280, USA; Small Molecule Discovery Center, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94143-2280, USA
| | - Markus-Frederik Bohn
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94143-2280, USA
| | - Emily J Connelly
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94143-2280, USA
| | - Kristin Wucherer
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94143-2280, USA
| | - Chayanid Ongpipattanakul
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94143-2280, USA
| | - Regan F Volk
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94143-2280, USA
| | - Shih-Wei Chuo
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94143-2280, USA
| | - Michelle R Arkin
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94143-2280, USA; Small Molecule Discovery Center, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94143-2280, USA
| | - Adam R Renslo
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94143-2280, USA; Small Molecule Discovery Center, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94143-2280, USA
| | - Charles S Craik
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94143-2280, USA.
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3
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Abdelhamid AO, Ismail ZH, Abdel-Aziem A. Reactions with Hydrazonoyl Halides 601: Synthesis of Thieno[2′,3′:4,5] Pyrimidino[1,2-b][1,2,4,5]tetrazines, [1]benzothieno[2′,3′:4,5]pyrimidino [1,2-b][1,2,4,5]tetrazines, Pyrazolo[3′,4′:4,5]pyrimidino[1,2-b] [1,2,4,5]tetrazines and Pyrazolo[3,4-d]pyridazines. JOURNAL OF CHEMICAL RESEARCH 2019. [DOI: 10.3184/030823407x256118] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Thieno[2′,3′:4,5]pyrimidino[1,2- b][1,2,4,5]tetrazine, [1]benzothieno-[2′,3′:4,5]pyrimidino[1,2- b][1,2,4,5]tetrazine, pyrazolo [3′,4′:4,5]pyrimidino[1,2- b][1,2,4,5]tetrazine, triazolo[4,3- a]pyrimidin-5(1 H)-one, 1-{[2-(1-benzofuran-2-yl)-5-phenyl-4,5-dihydro-1 H-pyrazol-1-yl]-4-substituted-1,3-thiazol-5-yl}-2-phenyldiazene, 3-acyl-4-(1-benzofuran-2-ylcarbonyl) pyrazole and pyrazolo[3,4- d]pyridazine derivatives could be obtained via reactions of hydrazonoyl halides with the appropriate pyrimidine-2-thione, 3-amino-5,6-dimethyl-2-sulfanylthieno[2,3- d]pyrimidin-4(3 H)-one, 5-amino-6-mercapto-1-phenyl-1,5-dihydropyrazolo[3,4- d]pyrimidin-4-one and 1-(benzofuran-2-yl)-3-(dimethylamino)prop-2-en-1-one. Structures of the products have been determined by elemental analyses, spectral data studies and alternative synthesis whenever possible.
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Affiliation(s)
- Abdou O. Abdelhamid
- Department of Chemistry, Faculty of Science, Cairo University, Giza 12613, Egypt
| | - Zeineb H. Ismail
- Department of Chemistry, Faculty of Science (Girls Branch), Al-Azhar University, Cairo, Egypt
| | - Anhar Abdel-Aziem
- Department of Chemistry, Faculty of Science (Girls Branch), Al-Azhar University, Cairo, Egypt
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4
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Shawali AS, Sayed AR. A convenient one-pot synthesis of 3-arylazo derivatives of azino[b][1,2,4,5]tetrazines. JOURNAL OF CHEMICAL RESEARCH 2019. [DOI: 10.3184/0308234041423718] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The reactions of 3-chloro-1,5-diarylformazans 1 with 3-amino-2-thiouracils 2(4) and 3-amino-2-thioxo-6-methyl-1,2, 4-triazin-5(4H)-ones 6 and their methylthio derivatives 3(5) and 7, respectively provide easy access to synthesis of 3-arylazo derivatives of 1,4-dihydro-1,8-disubstituted pyrimido[1,2-b][1,2,4,5]tetrazin-6-ones 8(9) and 1,4-dihydro-1-aryl-7-methyl[1,2,4]triazino[4,3-b][1,2,4,5]-tetrazin-6-ones (10), respectively.
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Affiliation(s)
- Ahmad S. Shawali
- Department of Chemistry, Faculty of Science, University of Cairo Giza, Egypt
| | - Abdelwahed R. Sayed
- Department of Chemistry, Faculty of Science, University of Cairo Giza, Egypt
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5
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Fear G, Komarnytsky S, Raskin I. Protease inhibitors and their peptidomimetic derivatives as potential drugs. Pharmacol Ther 2006; 113:354-68. [PMID: 17098288 PMCID: PMC7112583 DOI: 10.1016/j.pharmthera.2006.09.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2006] [Accepted: 09/05/2006] [Indexed: 01/28/2023]
Abstract
Precise spatial and temporal regulation of proteolytic activity is essential to human physiology. Modulation of protease activity with synthetic peptidomimetic inhibitors has proven to be clinically useful for treating human immunodeficiency virus (HIV) and hypertension and shows potential for medicinal application in cancer, obesity, cardiovascular, inflammatory, neurodegenerative diseases, and various infectious and parasitic diseases. Exploration of natural inhibitors and synthesis of peptidomimetic molecules has provided many promising compounds performing successfully in animal studies. Several protease inhibitors are undergoing further evaluation in human clinical trials. New research strategies are now focusing on the need for improved comprehension of protease-regulated cascades, along with precise selection of targets and improved inhibitor specificity. It remains to be seen which second generation agents will evolve into approved drugs or complementary therapies.
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Affiliation(s)
- Georgie Fear
- Biotech Center, Rutgers University, 59 Dudley Road, New Brunswick, NJ 08901, USA.
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6
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Abdelhamid AO, Elghandour AH, Ahmed SA, Zaki YH. Reaction of hydrazonoyl halides 49 : Synthesis and antimicrobial activity of some new pyrimido[1,2-b][1,2,4,5]tetrazin-6-one, tetrazino[3,2-b]quinazolin-5-one, pyrimidino[1,2-b]1,2,4,5-tetrazin-5-one and triazolo[4,3-a]pyrimidine derivatives. J Sulphur Chem 2006. [DOI: 10.1080/17415990500322859] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Abdou O. Abdelhamid
- a Department of Chemistry, Faculty of Science , Cairo University , Giza, 12316, Egypt
| | - Ahmed H. Elghandour
- b Department of Chemistry, Faculty of Science , Beni-Suef University , Beni-Suef, Egypt
| | - Sayed A. Ahmed
- b Department of Chemistry, Faculty of Science , Beni-Suef University , Beni-Suef, Egypt
| | - Yasser H. Zaki
- b Department of Chemistry, Faculty of Science , Beni-Suef University , Beni-Suef, Egypt
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7
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Abbas IM, Riyadh SM, Abdallah MA, Gomha SM. A novel route to tetracyclic fused tetrazines and thiadiazines. J Heterocycl Chem 2006. [DOI: 10.1002/jhet.5570430419] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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8
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Scozzafava A, Mastrolorenzo A, Supuran CT. Agents that target cysteine residues of biomolecules and their therapeutic potential. Expert Opin Ther Pat 2005. [DOI: 10.1517/13543776.11.5.765] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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9
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Morcock DR, Thomas JA, Gagliardi TD, Gorelick RJ, Roser JD, Chertova EN, Bess JW, Ott DE, Sattentau QJ, Frank I, Pope M, Lifson JD, Henderson LE, Crise BJ. Elimination of retroviral infectivity by N-ethylmaleimide with preservation of functional envelope glycoproteins. J Virol 2005; 79:1533-42. [PMID: 15650179 PMCID: PMC544125 DOI: 10.1128/jvi.79.3.1533-1542.2005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The zinc finger motifs in retroviral nucleocapsid (NC) proteins are essential for viral replication. Disruption of these Cys-X2-Cys-X4-His-X4-Cys zinc-binding structures eliminates infectivity. To determine if N-ethylmaleimide (NEM) can inactivate human immunodeficiency virus type 1 (HIV-1) or simian immunodeficiency virus (SIV) preparations by alkylating cysteines of NC zinc fingers, we treated infectious virus with NEM and evaluated inactivation of infectivity in cell-based assays. Inactivation was rapid and proportional to the NEM concentration. NEM treatment of HIV-1 or SIV resulted in extensive covalent modification of NC and other internal virion proteins. In contrast, viral envelope glycoproteins, in which the cysteines are disulfide bonded, remained intact and functional, as assayed by high-performance liquid chromatography, fusion-from-without analyses, and dendritic cell capture. Quantitative PCR assays for reverse transcription intermediates showed that NEM and 2,2'-dipyridyl disulfide (aldrithiol-2), a reagent which inactivates retroviruses through oxidation of cysteines in internal virion proteins such as NC, blocked HIV-1 reverse transcription prior to the formation of minus-strand strong-stop products. However, the reverse transcriptase from NEM-treated virions remained active in exogenous template assays, consistent with a role for NC in reverse transcription. Since disruption of NC zinc finger structures by NEM blocks early postentry steps in the retroviral infection cycle, virus preparations with modified NC proteins may be useful as vaccine immunogens and probes of the role of NC in viral replication.
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Affiliation(s)
- David R Morcock
- AIDS Vaccine Program, SAIC Frederick, NCI-Frederick, Building 535, 5th Floor, PO Box B, Frederick, MD 21702, USA
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10
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Di Grandi MJ, Curran KJ, Baum EZ, Bebernitz G, Ellestad GA, Ding WD, Lang SA, Rossi M, Bloom JD. Pyrimido[1,2-b]-1,2,4,5-tetrazin-6-ones as HCMV protease inhibitors: a new class of heterocycles with flavin-like redox properties. Bioorg Med Chem Lett 2004; 13:3483-6. [PMID: 14505653 DOI: 10.1016/s0960-894x(03)00789-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The synthesis and biological activity of pyrimidotetrazin-6-ones against HCMV protease is described. The mechanism of action for these inhibitors is the oxidation of several cysteine residues to generate cross-linked enzyme.
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11
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Affiliation(s)
- Liang Tong
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA.
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12
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Wittwer AJ, Funckes-Shippy CL, Hippenmeyer PJ. Recombinant full-length human cytomegalovirus protease has lower activity than recombinant processed protease domain in purified enzyme and cell-based assays. Antiviral Res 2002; 55:291-306. [PMID: 12103430 DOI: 10.1016/s0166-3542(02)00051-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Herpesviruses encode a protease that is essential for virus replication. The protease undergoes cleavage to a processed form during capsid maturation. A recombinant 75 kDa form of the protease from human cytomegalovirus was purified and compared with the recombinant 29 kDa processed form. Modification with an active site titrant suggested that most of each recombinant protease preparation was active (66 and 86%, respectively). Protease activity was compared using a low-molecular weight peptide substrate and the native substrate, capsid assembly protein. In addition, a cell-based assay for both enzymes was developed in which the target sequence of the protease has been fused inframe into the herpes simplex virus VP16 molecule. Cleavage of the fusion protein by the protease releases the carboxyl terminal transactivation domain, resulting in a decrease in the ability of the fusion molecule to transactivate a target promoter linked to a reporter gene in mammalian cells. Results suggest that the 75 kDa form of the enzyme is significantly less active than the 29 kDa form by all criteria.
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Affiliation(s)
- Arthur J Wittwer
- Pharmacia Discovery Research, 700 Chesterfield Village Parkway North, St. Louis, MO 63198, USA
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13
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Shawali AS, Abdallah MA, Zayed MM. A convenient one-pot synthesis and antimicrobial activity of pyrimido[1,2-b][1,2,4,5]tetrazines. J Heterocycl Chem 2002. [DOI: 10.1002/jhet.5570390105] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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14
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15
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Matsumoto M, Misawa S, Chiba N, Takaku H, Hayashi H. Selective nonpeptidic inhibitors of herpes simplex virus type 1 and human cytomegalovirus proteases. Biol Pharm Bull 2001; 24:236-41. [PMID: 11256477 DOI: 10.1248/bpb.24.236] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The proteases encoded by herpesviruses including herpes simplex virus type 1 (HSV-1) and human cytomegalovirus (HCMV) are attractive targets for antiviral drug development because of their important roles in viral replication. We randomly screened a chemical compound library for inhibitory activity against HSV-1 protease. 1,4-Dihydroxynaphthalene and three naphthoquinones were found to be potent inhibitors of HSV-1 protease with IC50 values of 6.4 to 16.9 microM. Inhibitory mode analysis of the compounds against HSV-1 protease suggested that, in spite of structural similarities, only 1,4-dihydroxynaphthalene was a competitive inhibitor, whereas the three naphthoquinones were noncompetitive inhibitors. Among all assayed dihydroxynaphthalene derivatives in the chemical compound library, 1,4-dihydroxynaphthalene proved to be the most potent inhibitor of HSV-1 protease. Therefore, the two hydroxyl groups located at positions 1 and 4 on the naphthalene structure seemed essential for exertion of a potent inhibitory activity against HSV-1 protease. In addition, we have found that these compounds are also potent inhibitors of HCMV protease with extremely low micromolar IC50 values. This differed from the results of inhibitory mode analysis of HSV-1 protease, 1,4-dihydroxynaphthalene was a noncompetitive inhibitor of HCMV protease, and three naphthoquinones were competitive inhibitors. These compounds showed no effective inhibitory activity against several mammalian serine proteases (trypsin, chymotrypsin, kallikrein, plasmin, thrombin and Factor Xa) at 100 microM. These results suggest that 1,4-dihydroxynaphthalene and three naphthoquinones may be useful in the development of nonpeptidic antiherpesvirus agents.
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Affiliation(s)
- M Matsumoto
- Pharmaceuticals and Biotechnology Laboratory, Japan Energy Corporation, Saitama.
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16
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Kuzmic P, Elrod KC, Cregar LM, Sideris S, Rai R, Janc JW. High-throughput screening of enzyme inhibitors: simultaneous determination of tight-binding inhibition constants and enzyme concentration. Anal Biochem 2000; 286:45-50. [PMID: 11038272 DOI: 10.1006/abio.2000.4685] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Active site titration by a reversible tight-binding inhibitor normally depends on prior knowledge of the inhibition constant. Conversely, the determination of tight-binding inhibition constants normally requires prior knowledge of the active enzyme concentration. Often, neither of these quantities is known with sufficient accuracy. This paper describes experimental conditions under which both the enzyme active site concentration and the tight-binding inhibition constant can be determined simultaneously from a single dose-response curve. Representative experimental data are shown for the inhibition of human kallikrein.
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Affiliation(s)
- P Kuzmic
- BioKin, Ltd., 1652 South Grand Avenue, Suite 337, Pullman, Washington 99163, USA.
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17
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Abstract
This review summarizes evidence that most of cell protein degradation is maintained by pathways transferring energy from glucose to reduction of enzymic and nonenzymic proteins (redox-responsive). In contrast, a major subcomponent of proteolysis is simultaneously independent of the cell redox network (redox-unresponsive). Thus far, direct and indirect redox-responsive proteolytic effector mechanisms characterized by various investigators include: several classes of proteases, some peptide protease inhibitors, substrate conjugation systems, substrate redox and folding status, cytoskeletal-membrane kinesis, metal homeostasis, and others. The present focus involves redox control of sulfhydryl proteases and proteolytic pathways of mammalian muscle; however, other mechanisms, cell types, and species are also surveyed. The diversity of redox-responsive catabolic mechanisms reveals that the machinery of protein turnover evolved with fundamental dependencies upon the cell redox network, as observed in many species. The net redox status of a reversible proteolytic effector mechanism represents the balance between combined oxidative inactivating influences versus reductive activating influences. Similar to other proteins, redox-responsive proteolytic effectors appear to be oxidized by mixed disulfide formation, nitrosation, reactive oxygen species, and associations or reactions with metal ions and various pro-oxidative metabolites. Systems reducing the proteolytic machinery include major redox enzyme chains, such as thioredoxins or glutaredoxins, and perhaps various reductive metabolites, including glutathione and dihydrolipoic acid. Much of mammalian intracellular protein degradation is reversibly responsive to noninjurious experimental intervention in the reductive energy supply-demand balance. Proteolysis is reversibly inhibited by diamide or dehydroascorbic acid; and such antiproteolytic actions are strongly dependent on the cell glucose supply. However, gross redox-responsive proteolysis is not accompanied by ATP depletion or vice versa. Redox-responsive proteolysis includes Golgi-endoplasmic reticulum degradation, lysosomal degradation, and some amount of extravesicular degradation, all comprising more than half of total cell proteolysis. Speculatively, redox-dependent proteolysis exhibits features expected of a controlling influence coordinating distinct proteolytic processes under some intracellular conditions.
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Affiliation(s)
- T D Lockwood
- Department of Pharmacology and Toxicology, School of Medicine, Wright State University, Dayton, OH 45435, USA
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18
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Abstract
Viruses of the family Herpesviridae are responsible for a diverse set of human diseases. The available treatments are largely ineffective, with the exception of a few drugs for treatment of herpes simplex virus (HSV) infections. For several members of this DNA virus family, advances have been made recently in the biochemistry and structural biology of the essential viral protease, revealing common features that may be possible to exploit in the development of a new class of anti-herpesvirus agents. The herpesvirus proteases have been identified as belonging to a unique class of serine protease, with a Ser-His-His catalytic triad. A new, single domain protein fold has been determined by X-ray crystallography for the proteases of at least three different herpesviruses. Also unique for serine proteases, dimerization has been shown to be required for activity of the cytomegalovirus and HSV proteases. The dimerization requirement seriously impacts methods needed for productive, functional analysis and inhibitor discovery. The conserved functional and catalytic properties of the herpesvirus proteases lead to common considerations for this group of proteases in the early phases of inhibitor discovery. In general, classical serine protease inhibitors that react with active site residues do not readily inactivate the herpesvirus proteases. There has been progress however, with activated carbonyls that exploit the selective nucleophilicity of the active site serine. In addition, screening of chemical libraries has yielded novel structures as starting points for drug development. Recent crystal structures of the herpesvirus proteases now allow more direct interpretation of ligand structure-activity relationships. This review first describes basic functional aspects of herpesvirus protease biology and enzymology. Then we discuss inhibitors identified to date and the prospects for their future development.
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Affiliation(s)
- L Waxman
- Department of Antiviral Research, Merck Research Laboratories, West Point, PA 19486, USA
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19
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Shawali AS, Elghandour AA, El‐Sheikh SM. A new one‐step synthesis of pyrimido‐[1,2‐
b
][1,2,4,5]tetrazines. HETEROATOM CHEMISTRY 2000. [DOI: 10.1002/(sici)1098-1071(2000)11:2<87::aid-hc1>3.0.co;2-#] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Ahmad S. Shawali
- Department of Chemistry, Faculty of Science, University of Cairo, Giza, Egypt
| | - Ahmad A. Elghandour
- Department of Chemistry, Faculty of Science, University of Cairo, Giza, Egypt
| | - Said M. El‐Sheikh
- Department of Chemistry, Faculty of Science, University of Cairo, Giza, Egypt
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20
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Smith DG, Gribble AD, Haigh D, Ife RJ, Lavery P, Skett P, Slingsby BP, Stacey R, Ward RW, West A. The inhibition of human cytomegalovirus (hCMV) protease by hydroxylamine derivatives. Bioorg Med Chem Lett 1999; 9:3137-42. [PMID: 10560740 DOI: 10.1016/s0960-894x(99)00539-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Aryl hydroxylamine derivatives have been synthesised that are some of the most potent inhibitors of hCMV protease prepared to date (IC50 14-60 nM). Mass spectrometry studies indicate that oxazinone derived hydroxylamines inhibit the enzyme by acylation of Ser132 whereas non-oxazinone derived hydroxylamines appear to inhibit via formation of a sulfinanilide at Cys138.
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Affiliation(s)
- D G Smith
- SmithKline Beecham Pharmaceuticals, New Frontiers Science Park, Harlow, Essex, UK.
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21
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Ertl P, Cooper D, Allen G, Slater MJ. 2-chloro-3-substituted-1,4-naphthoquinone inactivators of human cytomegalovirus protease. Bioorg Med Chem Lett 1999; 9:2863-6. [PMID: 10522707 DOI: 10.1016/s0960-894x(99)00489-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A random screening approach has identified 2-chloro-3-substituted-1,4-naphthoquinones as potent inactivators of HCMV protease. Enzyme inactivation is due to modification of Cys202. Two of the most potent compounds maintain activity against HCMV in a plaque reduction assay.
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Affiliation(s)
- P Ertl
- GlaxoWellcome Medicines Research Centre, Stevenage, UK
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22
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Ogilvie WW, Yoakim C, Dô F, Haché B, Lagacé L, Naud J, O'Meara JA, Déziel R. Synthesis and antiviral activity of monobactams inhibiting the human cytomegalovirus protease. Bioorg Med Chem 1999; 7:1521-31. [PMID: 10482444 DOI: 10.1016/s0968-0896(99)00094-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A series of monobactam inhibitors of HCMV (N(o)) protease bearing a heterocycle linked by a methylene group at C-4 is described. Inhibitors containing a heterocycle such as a 2-furyl, 2-thiophenyl, 4-methyl-2-tetrazole and 2-benzothiazole were found to be active in a plaque reduction assay. Furthermore, 2-benzothiazole derivatives were shown to inhibit the HCMV protease activity inside cells by using a cell transfection assay, indicating that their antiviral activity in the plaque reduction assay could be attributed to protease inhibition.
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Affiliation(s)
- W W Ogilvie
- Boehringer Ingelheim (Canada) Ltd., Bio-Méga Research Division, Laval, Québec, Canada.
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23
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Pinto IL, Jarvest RL, Clarke B, Dabrowski CE, Fenwick A, Gorczyca MM, Jennings LJ, Lavery P, Sternberg EJ, Tew DG, West A. Inhibition of human cytomegalovirus protease by enedione derivatives of thieno[2,3-d]oxazinones through a novel dual acylation/alkylation mechanism. Bioorg Med Chem Lett 1999; 9:449-52. [PMID: 10091700 DOI: 10.1016/s0960-894x(99)00005-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Enedione derivatives of thieno[2,3-d]oxazinones are nanomolar inhibitors of CMV protease which act through a novel dual acylation of the catalytic serine and alkylation of the protease cysteine 161 via a Michael addition to the enedione moiety of the inhibitor.
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Affiliation(s)
- I L Pinto
- SmithKline Beecham Pharmaceuticals, New Frontiers Science Park, Harlow, Essex, UK.
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24
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Dhanak D, Keenan RM, Burton G, Kaura A, Darcy MG, Shah DH, Ridgers LH, Breen A, Lavery P, Tew DG, West A. Benzothiopyran-4-one based reversible inhibitors of the human cytomegalovirus (HCMV) protease. Bioorg Med Chem Lett 1998; 8:3677-82. [PMID: 9934494 DOI: 10.1016/s0960-894x(98)00666-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A novel class of CMV protease inhibitors based on a benzothiopyran-S,S-dioxide nucleus has been discovered. Enzyme kinetic data supports a reversible mode of inhibition for a representative member of this class, 2-(3-pyridyl-N-oxide)benzothiopyran-4-one-S,S-dioxide, 1. Experiments in the presence and absence of the disulfide reducing agent DTT suggest that the inhibition by 1 is not due to oxidative inactivation of the enzyme. Also presented are results of some SAR studies of the benzothiopyranone ring system.
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Affiliation(s)
- D Dhanak
- SmithKline Beecham Pharmaceuticals, Collegeville, PA 19426-0989, USA
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25
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Abstract
Currently, there are a number of approved antiviral agents for use in the treatment of viral infections. However, many instances exist in which the use of a second antiviral agent would be beneficial because it would allow the option of either an alternative or a combination therapeutic approach. Accordingly, virus-encoded proteases have emerged as new targets for antiviral intervention. Molecular studies have indicated that viral proteases play a critical role in the life cycle of many viruses by effecting the cleavage of high-molecular-weight viral polyprotein precursors to yield functional products or by catalyzing the processing of the structural proteins necessary for assembly and morphogenesis of virus particles. This review summarizes some of the important general features of virus-encoded proteases and highlights new advances and/or specific challenges that are associated with the research and development of viral protease inhibitors. Specifically, the viral proteases encoded by the herpesvirus, retrovirus, hepatitis C virus, and human rhinovirus families are discussed.
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Affiliation(s)
- A K Patick
- Agouron Pharmaceuticals, Inc., San Diego, California 92121, USA.
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26
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Flynn DL, Abood NA, Holwerda BC. Recent advances in antiviral research: identification of inhibitors of the herpesvirus proteases. Curr Opin Chem Biol 1997; 1:190-6. [PMID: 9667847 DOI: 10.1016/s1367-5931(97)80009-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Major advances have been reported in the last two years regarding the molecular biology and structural properties of the herpesvirus proteases. X-ray diffraction studies have enabled several groups to solve the structure of the human cytomegalovirus protease. Fluorescence-based substrate assays have also been recently reported. These substrates exhibit sufficient kinetic and sensitivity properties to enable high-throughput screening efforts dedicated toward the discovery of protease inhibitors. Three classes of inhibitors have been reported recently: nonpeptidic aryl trifluoromethylketones; alternate substrate inhibitors (benzoxazinones/azalactones); and thiol-modifying inhibitors. The thiol-modifying class offers a unique opportunity to discover inhibitors specific to the human cytomegalovirus protease, as this protease requires reduced cysteine residues for its enzymatic activity.
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Affiliation(s)
- D L Flynn
- Searle Research and Development, Department of Medicinal Chemistry, 800 N Lindbergh Blvd, St Louis, MO 63167, USA.
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27
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Abstract
Herpesvirus proteases have emerged as targets for the development of novel antiviral drugs. These enzymes, which are necessary for the replication of all herpesviruses, are serine proteases, but possess a unique structure as revealed by solution of the crystal structure of human cytomegalovirus protease. Many of the biochemical properties of these enzymes are now explained by the structure. Conventional serine protease inhibitors are not potent inhibitors of these enzymes and therefore the search for potent inhibitors possessing necessary features of an effective antiviral will require novel approaches. The three-dimensional structure serves as a milestone for continued endeavors towards this goal.
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Affiliation(s)
- B C Holwerda
- Searle Research and Development, St. Louis, MO 63198, USA.
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28
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Snyder SW, Edalji RP, Lindh FG, Walter KA, Solomon L, Pratt S, Steffy K, Holzman TF. Initial characterization of autoprocessing and active-center mutants of CMV proteinase. JOURNAL OF PROTEIN CHEMISTRY 1996; 15:763-74. [PMID: 9008301 DOI: 10.1007/bf01887151] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Human cytomegalovirus (CMV) encodes a unique serine proteinase that is required in the maturation of the viral capsid. The CMV proteinase can undergo autocatalytic activation and is subject to proteolytic self-inactivation. Mutant enzyme forms were prepared to eliminate the initial autoprocessing site and thus form an active single-chain protein for structure-function studies. Two mutants of CMV proteinase were cloned and expressed in Escherichia coli. The A143V mutant was a conservative substitution at the first internal cleavage site. The S132A mutant modified one of the triad of residues responsible for catalytic activity. Through the use of computer-controlled high-cell-density fermentations the mutant proteins were expressed in E. coli at approximately 170 mg/L as both soluble (approximately 40% of total) and inclusion-body forms (approximately 60% of total). The soluble enzyme was purified by standard methods; inclusion-body protein was isolated by standard methods after refolding and solubilization in guanidine or urea. Sedimentation equilibrium and sedimentation velocity analyses reveal that the enzyme undergoes concentration-dependent aggregation. It exhibits a monomer <==> dimer equilibrium (Kd = 1 microM) at low concentrations and remains dimeric at high concentrations (28 mg/ml). Differential scanning calorimetry data for protein thermal unfolding fit best to a non-two-state model with two components (Tm = 52.3 and 55.3 degrees C) which subsequently aggregate upon unfolding. Analysis of the short-UV circular dichroism spectra of protein forms resulting from expression as soluble molecules (not refolded) reveals that the two mutants have very similar secondary structures which comprise a mixed structural motif of 20% alpha-helix, 26% beta-sheet, and 53% random coil. Though soluble and active (A143V mutant only), CD analysis revealed that protein refolded from inclusion bodies did not exhibit spectra identical to that of protein expressed only in soluble form.
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Affiliation(s)
- S W Snyder
- Protein Biochemistry, Pharmaceutical Discovery, Abbott Laboratories, Abbott Park, Illinois 60064, USA
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