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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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Rehman AU, Lu S, Khan AA, Khurshid B, Rasheed S, Wadood A, Zhang J. Hidden allosteric sites and De-Novo drug design. Expert Opin Drug Discov 2021; 17:283-295. [PMID: 34933653 DOI: 10.1080/17460441.2022.2017876] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Hidden allosteric sites are not visible in apo-crystal structures, but they may be visible in holo-structures when a certain ligand binds and maintains the ligand intended conformation. Several computational and experimental techniques have been used to investigate these hidden sites but identifying them remains a challenge. AREAS COVERED This review provides a summary of the many theoretical approaches for predicting hidden allosteric sites in disease-related proteins. Furthermore, promising cases have been thoroughly examined to reveal the hidden allosteric site and its modulator. EXPERT OPINION In the recent past, with the development in scientific techniques and bioinformatics tools, the number of drug targets for complex human diseases has significantly increased but unfortunately most of these targets are undruggable due to several reasons. Alternative strategies such as finding cryptic (hidden) allosteric sites are an attractive approach for exploitation of the discovery of new targets. These hidden sites are difficult to recognize compared to allosteric sites, mainly due to a lack of visibility in the crystal structure. In our opinion, after many years of development, MD simulations are finally becoming successful for obtaining a detailed molecular description of drug-target interaction.
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Affiliation(s)
- Ashfaq Ur Rehman
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Clinical and Fundamental Research Center, Renji Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Shaoyong Lu
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Clinical and Fundamental Research Center, Renji Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Abdul Aziz Khan
- Bio-X Institutes, Key Laboratory for the Genetics of Development and Neuropsychiatric Disorders (Ministry of Education), Shanghai Key Laboratory of Psychotic Disorders, and Brain Science and Technology Research Center, Institute of Psychology and Behavioral Sciences, Shanghai Jiao Tong University, Shanghai, China
| | - Beenish Khurshid
- Department of Biochemistry, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Salman Rasheed
- National Center for Bioinformatics, Quaid-e-Azam University, Islamabad, Pakistan
| | - Abdul Wadood
- Department of Biochemistry, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Jian Zhang
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Clinical and Fundamental Research Center, Renji Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China.,School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
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Sandner A, Ngo K, Sager CP, Scheer F, Daude M, Diederich WE, Heine A, Klebe G. Which Properties Allow Ligands to Open and Bind to the Transient Binding Pocket of Human Aldose Reductase? Biomolecules 2021; 11:biom11121837. [PMID: 34944481 PMCID: PMC8699021 DOI: 10.3390/biom11121837] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/30/2021] [Accepted: 12/02/2021] [Indexed: 11/16/2022] Open
Abstract
The transient specificity pocket of aldose reductase only opens in response to specific ligands. This pocket may offer an advantage for the development of novel, more selective ligands for proteins with similar topology that lack such an adaptive pocket. Our aim was to elucidate which properties allow an inhibitor to bind in the specificity pocket. A series of inhibitors that share the same parent scaffold but differ in their attached aromatic substituents were screened using ITC and X-ray crystallography for their ability to occupy the pocket. Additionally, we investigated the electrostatic potentials and charge distribution across the attached terminal aromatic groups with respect to their potential to bind to the transient pocket of the enzyme using ESP calculations. These methods allowed us to confirm the previously established hypothesis that an electron-deficient aromatic group is an important prerequisite for opening and occupying the specificity pocket. We also demonstrated from our crystal structures that a pH shift between 5 and 8 does not affect the binding position of the ligand in the specificity pocket. This allows for a comparison between thermodynamic and crystallographic data collected at different pH values.
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Affiliation(s)
- Anna Sandner
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35037 Marburg, Germany; (A.S.); (K.N.); (A.H.)
| | - Khang Ngo
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35037 Marburg, Germany; (A.S.); (K.N.); (A.H.)
| | - Christoph P. Sager
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35037 Marburg, Germany; (A.S.); (K.N.); (A.H.)
| | - Frithjof Scheer
- Institut für Pharmazeutische Chemie, Zentrum für Tumor und Immunbiologie, Philipps-Universität Marburg, Hans-Meerwein-Straße 3, 35032 Marburg, Germany; (F.S.); (W.E.D.)
| | - Michael Daude
- Zentrum für Tumor und Immunbiologie, Core Facility Medicinal Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Straße 3, 35043 Marburg, Germany;
| | - Wibke E. Diederich
- Institut für Pharmazeutische Chemie, Zentrum für Tumor und Immunbiologie, Philipps-Universität Marburg, Hans-Meerwein-Straße 3, 35032 Marburg, Germany; (F.S.); (W.E.D.)
- Zentrum für Tumor und Immunbiologie, Core Facility Medicinal Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Straße 3, 35043 Marburg, Germany;
| | - Andreas Heine
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35037 Marburg, Germany; (A.S.); (K.N.); (A.H.)
| | - Gerhard Klebe
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35037 Marburg, Germany; (A.S.); (K.N.); (A.H.)
- Correspondence: ; Tel.: +49-6421-28-21313
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Mokhtari DA, Appel MJ, Fordyce PM, Herschlag D. High throughput and quantitative enzymology in the genomic era. Curr Opin Struct Biol 2021; 71:259-273. [PMID: 34592682 PMCID: PMC8648990 DOI: 10.1016/j.sbi.2021.07.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 07/23/2021] [Indexed: 12/28/2022]
Abstract
Accurate predictions from models based on physical principles are the ultimate metric of our biophysical understanding. Although there has been stunning progress toward structure prediction, quantitative prediction of enzyme function has remained challenging. Realizing this goal will require large numbers of quantitative measurements of rate and binding constants and the use of these ground-truth data sets to guide the development and testing of these quantitative models. Ground truth data more closely linked to the underlying physical forces are also desired. Here, we describe technological advances that enable both types of ground truth measurements. These advances allow classic models to be tested, provide novel mechanistic insights, and place us on the path toward a predictive understanding of enzyme structure and function.
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Affiliation(s)
- D A Mokhtari
- Department of Biochemistry, Stanford University, Stanford, CA, 94305, USA
| | - M J Appel
- Department of Biochemistry, Stanford University, Stanford, CA, 94305, USA
| | - P M Fordyce
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA; ChEM-H Institute, Stanford University, Stanford, CA, 94305, USA; Department of Genetics, Stanford University, Stanford, CA, 94305, USA; Chan Zuckerberg Biohub San Francisco, CA, 94110, USA.
| | - D Herschlag
- Department of Biochemistry, Stanford University, Stanford, CA, 94305, USA; Department of Chemical Engineering, Stanford University, Stanford, CA, 94305, USA; ChEM-H Institute, Stanford University, Stanford, CA, 94305, USA.
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Naimo E, Zischke J, Schulz TF. Recent Advances in Developing Treatments of Kaposi's Sarcoma Herpesvirus-Related Diseases. Viruses 2021; 13:1797. [PMID: 34578378 PMCID: PMC8473310 DOI: 10.3390/v13091797] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/30/2021] [Accepted: 09/01/2021] [Indexed: 12/27/2022] Open
Abstract
Kaposi-sarcoma-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV-8) is the causative agent of several malignancies, including Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease (MCD). Active KSHV replication has also been associated with a pathological condition called KSHV inflammatory cytokine syndrome (KICS), and KSHV may play a role in rare cases of post-transplant polyclonal lymphoproliferative disorders. Several commonly used herpesviral DNA polymerase inhibitors are active against KSHV in tissue culture. Unfortunately, they are not always efficacious against KSHV-induced diseases. To improve the outcome for the patients, new therapeutics need to be developed, including treatment strategies that target either viral proteins or cellular pathways involved in tumor growth and/or supporting the viral life cycle. In this review, we summarize the most commonly established treatments against KSHV-related diseases and review recent developments and promising new compounds that are currently under investigation or on the way to clinical use.
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Affiliation(s)
- Eleonora Naimo
- Institute of Virology, Hannover Medical School, 30625 Hannover, Germany; (E.N.); (J.Z.)
- German Centre for Infection Research, Hannover-Braunschweig Site, 38023 Braunschweig, Germany
| | - Jasmin Zischke
- Institute of Virology, Hannover Medical School, 30625 Hannover, Germany; (E.N.); (J.Z.)
- German Centre for Infection Research, Hannover-Braunschweig Site, 38023 Braunschweig, Germany
| | - Thomas F. Schulz
- Institute of Virology, Hannover Medical School, 30625 Hannover, Germany; (E.N.); (J.Z.)
- German Centre for Infection Research, Hannover-Braunschweig Site, 38023 Braunschweig, Germany
- Cluster of Excellence 2155 RESIST, Institute of Virology, Hannover Medical School, 30625 Hannover, Germany
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Thompson MC, Yeates TO, Rodriguez JA. Advances in methods for atomic resolution macromolecular structure determination. F1000Res 2020; 9:F1000 Faculty Rev-667. [PMID: 32676184 PMCID: PMC7333361 DOI: 10.12688/f1000research.25097.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/25/2020] [Indexed: 12/13/2022] Open
Abstract
Recent technical advances have dramatically increased the power and scope of structural biology. New developments in high-resolution cryo-electron microscopy, serial X-ray crystallography, and electron diffraction have been especially transformative. Here we highlight some of the latest advances and current challenges at the frontiers of atomic resolution methods for elucidating the structures and dynamical properties of macromolecules and their complexes.
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Affiliation(s)
- Michael C. Thompson
- Department of Chemistry and Chemical Biology, University of California, Merced, CA, USA
| | - Todd O. Yeates
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA, USA
| | - Jose A. Rodriguez
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA, USA
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Sun Z, Wakefield AE, Kolossvary I, Beglov D, Vajda S. Structure-Based Analysis of Cryptic-Site Opening. Structure 2019; 28:223-235.e2. [PMID: 31810712 DOI: 10.1016/j.str.2019.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 09/10/2019] [Accepted: 11/12/2019] [Indexed: 01/07/2023]
Abstract
Many proteins in their unbound structures have cryptic sites that are not appropriately sized for drug binding. We consider here 32 proteins from the recently published CryptoSite set with validated cryptic sites, and study whether the sites remain cryptic in all available X-ray structures of the proteins solved without any ligand bound near the sites. It was shown that only few of these proteins have binding pockets that never form without ligand binding. Sites that are cryptic in some structures but spontaneously form in others are also rare. In most proteins the forming of pockets is affected by mutations or ligand binding at locations far from the cryptic site. To further explore these mechanisms, we applied adiabatic biased molecular dynamics simulations to guide the proteins from their ligand-free structures to ligand-bound conformations, and studied the distribution of druggability scores of the pockets located at the cryptic sites.
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Affiliation(s)
- Zhuyezi Sun
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Amanda Elizabeth Wakefield
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Department of Chemistry, Boston University, Boston, MA 02215, USA
| | - Istvan Kolossvary
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Dmitri Beglov
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Sandor Vajda
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Department of Chemistry, Boston University, Boston, MA 02215, USA.
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Cortina GA, Kasson PM. Predicting allostery and microbial drug resistance with molecular simulations. Curr Opin Struct Biol 2018; 52:80-86. [PMID: 30243041 PMCID: PMC6296865 DOI: 10.1016/j.sbi.2018.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 08/31/2018] [Accepted: 09/07/2018] [Indexed: 11/30/2022]
Abstract
Beta-lactamase enzymes mediate the most common forms of gram-negative antibiotic resistance affecting clinical treatment. They also constitute an excellent model system for the difficult problem of understanding how allosteric mutations can augment catalytic activity of already-competent enzymes. Multiple allosteric mutations have been identified that alter catalytic activity or drug-resistance spectrum in class A beta lactamases, but predicting these in advance continues to be challenging. Here, we review computational techniques based on structure and/or molecular simulation to predict such mutations. Structure-based techniques have been particularly helpful in developing graph algorithms for analyzing critical residues in beta-lactamase function, while classical molecular simulation has recently shown the ability to prospectively predict allosteric mutations increasing beta-lactamase activity and drug resistance. These will ultimately achieve the greatest power when combined with simulation methods that model reactive chemistry to calculate activation free energies directly.
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Affiliation(s)
- George A Cortina
- Departments of Molecular Physiology and of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, United States
| | - Peter M Kasson
- Departments of Molecular Physiology and of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, United States; Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala 75146, Sweden.
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Vajda S, Beglov D, Wakefield AE, Egbert M, Whitty A. Cryptic binding sites on proteins: definition, detection, and druggability. Curr Opin Chem Biol 2018; 44:1-8. [PMID: 29800865 PMCID: PMC6088748 DOI: 10.1016/j.cbpa.2018.05.003] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 05/03/2018] [Indexed: 12/30/2022]
Abstract
Many proteins in their unbound structures lack surface pockets appropriately sized for drug binding. Hence, a variety of experimental and computational tools have been developed for the identification of cryptic sites that are not evident in the unbound protein but form upon ligand binding, and can provide tractable drug target sites. The goal of this review is to discuss the definition, detection, and druggability of such sites, and their potential value for drug discovery. Novel methods based on molecular dynamics simulations are particularly promising and yield a large number of transient pockets, but it has been shown that only a minority of such sites are generally capable of binding ligands with substantial affinity. Based on recent studies, current methodology can be improved by combining molecular dynamics with fragment docking and machine learning approaches.
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Affiliation(s)
- Sandor Vajda
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, United States; Department of Chemistry, Boston University, Boston, MA 02215, United States.
| | - Dmitri Beglov
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, United States
| | - Amanda E Wakefield
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, United States; Department of Chemistry, Boston University, Boston, MA 02215, United States
| | - Megan Egbert
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, United States
| | - Adrian Whitty
- Department of Chemistry, Boston University, Boston, MA 02215, United States.
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Hu L, Liu Y, Wang Y, Wang Z, Huang J, Xue Y, Liu J, Liu Z, Chen Y, Zhang Y. Discovery of acylphloroglucinol-based meroterpenoid enantiomers as KSHV inhibitors from Hypericum japonicum. RSC Adv 2018; 8:24101-24109. [PMID: 35539193 PMCID: PMC9081833 DOI: 10.1039/c8ra04073g] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Accepted: 06/26/2018] [Indexed: 11/28/2022] Open
Abstract
Kaposi's sarcoma associated herpesvirus (KSHV) has gained considerable attention as a type of carcinogenic pathogen. Recent research suggests that KSHV has participated in the pathogenesis of Kaposi's sarcoma-related malignant neoplastic diseases. Viral lytic infection might be pivotal for the etiopathogenesis of KSHV-induced diseases; however, most clinical KSHV lytic replication inhibitors like ganciclovir, nelfinavir, or cidofovir do not restrain virus replication effectively enough to achieve clinical efficacy. In our continued pharmaceutical studies on Chinese herbal medicines, new acylphloroglucinol-based meroterpenoid enantiomers have been discovered from Hypericum japonicum. Most of these metabolites have potential inhibitory activities that target KSHV lytic replication. Amongst these analogues, compounds 1a and 1b possess an unreported ring system cyclopenta[b]chromene. Compounds 1a with 4a exhibit stronger inhibitory activities towards the lytic replication of KSHV in Vero cells. In addition, 1a and 4a have IC50 values of 8.30 and 4.90 μM and selectivity indexes of 23.49 and 25.70, respectively. Qualitative and quantitative SAR and molecular docking studies for acylphloroglucinol-based meroterpenoids with regard to anti-KSHV activity were conducted. An explanation for the variation in the activity and selectivity indexes was proposed in accordance with the predicted binding pose found with molecular docking to a putative target, thymidylate synthase (kTS). Compounds 1a and 4a have potential for further development and optimization of their anti-KSHV activities which could lead to new candidate drugs. New enantiomers (1a/1b–4a/4b) were discovered from Hypericum japonicum. 1a/1b possessed a novel ring system cyclopenta[b]chromene. 1a and 4a exhibited promising anti-KSHV activities. QSAR studies for enantiomers on anti-KSHV activity were conducted.![]()
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