1
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Lu F, Xia K, Su J, Yi J, Luo Z, Xu J, Gu Q, Chen B, Zhou H. Biochemical and structural characterization of chlorhexidine as an ATP-assisted inhibitor against type 1 methionyl-tRNA synthetase from Gram-positive bacteria. Eur J Med Chem 2024; 268:116303. [PMID: 38458107 DOI: 10.1016/j.ejmech.2024.116303] [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: 01/14/2024] [Revised: 02/27/2024] [Accepted: 03/02/2024] [Indexed: 03/10/2024]
Abstract
Methionyl-tRNA synthetase (MetRS) catalyzes the attachment of l-methionine (l-Met) to tRNAMet to generate methionyl-tRNAMet, an essential substrate for protein translation within ribosome. Owing to its indispensable biological function and the structural discrepancies with human counterpart, bacterial MetRS is considered an ideal target for developing antibacterials. Herein, chlorhexidine (CHX) was identified as a potent binder of Staphylococcus aureus MetRS (SaMetRS) through an ATP-aided affinity screening. The co-crystal structure showed that CHX simultaneously occupies the enlarged l-Met pocket (EMP) and the auxiliary pocket (AP) of SaMetRS with its two chlorophenyl groups, while its central hexyl linker swings upwards to interact with some conserved hydrophobic residues. ATP adopts alternative conformations in the active site cavity, and forms ionic bonds and water-mediated hydrogen bonds with CHX. Consistent with this synergistic binding mode, ATP concentration-dependently enhanced the binding affinity of CHX to SaMetRS from 10.2 μM (no ATP) to 0.45 μM (1 mM ATP). While it selectively inhibited two representative type 1 MetRSs from S. aureus and Enterococcus faecalis, CHX did not show significant interactions with three tested type 2 MetRSs, including human cytoplasmic MetRS, in the enzyme inhibition and biophysical binding assays, probably due to the conformational differences between two types of MetRSs at their EMP and AP. Our findings on CHX may inspire the design of MetRS-directed antimicrobials in future.
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Affiliation(s)
- Feihu Lu
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China; Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Kaijiang Xia
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China; Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Jingtian Su
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China; Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Jia Yi
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China; Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Zhiteng Luo
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China; Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Jun Xu
- Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Qiong Gu
- Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Bingyi Chen
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China; Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China.
| | - Huihao Zhou
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China; Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China.
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2
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Li SR, Zeng CM, Peng XM, Chen JP, Li S, Zhou CH. Benzopyrone-mediated quinolones as potential multitargeting antibacterial agents. Eur J Med Chem 2023; 262:115878. [PMID: 37866337 DOI: 10.1016/j.ejmech.2023.115878] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/12/2023] [Accepted: 10/12/2023] [Indexed: 10/24/2023]
Abstract
A new type of benzopyrone-mediated quinolones (BMQs) was rationally designed and efficiently synthesized as novel potential antibacterial molecules to overcome the global increasingly serious drug resistance. Some synthesized BMQs effectively suppressed the growth of the tested strains, outperforming clinical drugs. Notably, ethylidene-derived BMQ 17a exhibited superior antibacterial potential with low MICs of 0.5-2 μg/mL to clinical drugs norfloxacin, it not only displayed rapid bactericidal performance and inhibited bacterial biofilm formation, but also showed low toxicity toward human red blood cells and normal MDA-kb2 cells. Mechanistic investigation demonstrated that BMQ 17a could effectually induce bacterial metabolic disorders and promote the enhancement of reactive oxygen species to disrupt the bacterial antioxidant defense system. It was found that the active molecule BMQ 17a could not only form supramolecular complex with lactate dehydrogenase, which disturbed the biological functions, but also effectively embed into calf thymus DNA, thus affecting the normal function of DNA and achieving cell death. This work would provide an insight into developing new molecules to reduce drug resistance and expand antibacterial spectrum.
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Affiliation(s)
- Shu-Rui Li
- Institute of Bioorganic & Medicinal Chemistry, Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, China
| | - Chun-Mei Zeng
- Institute of Bioorganic & Medicinal Chemistry, Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, China
| | - Xin-Mei Peng
- School of Chemistry and Chemical Engineering, Qiannan Normal University for Nationalities, Duyun, 558000, China.
| | - Jin-Ping Chen
- Institute of Bioorganic & Medicinal Chemistry, Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, China
| | - Shuo Li
- School of Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China.
| | - Cheng-He Zhou
- Institute of Bioorganic & Medicinal Chemistry, Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, China.
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3
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Elbaramawi SS, Eissa AG, Noureldin NA, Simons C. Exploring Proteus mirabilis Methionine tRNA Synthetase Active Site: Homology Model Construction, Molecular Dynamics, Pharmacophore and Docking Validation. Pharmaceuticals (Basel) 2023; 16:1263. [PMID: 37765071 PMCID: PMC10535265 DOI: 10.3390/ph16091263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/23/2023] [Accepted: 09/01/2023] [Indexed: 09/29/2023] Open
Abstract
Currently, the treatment of Proteus mirabilis infections is considered to be complicated as the organism has become resistant to numerous antibiotic classes. Therefore, new inhibitors should be developed, targeting bacterial molecular functions. Methionine tRNA synthetase (MetRS), a member of the aminoacyl-tRNA synthetase family, is essential for protein biosynthesis offering a promising target for novel antibiotics discovery. In the context of computer-aided drug design (CADD), the current research presents the construction and analysis of a comparative homology model for P. mirabilis MetRS, enabling development of novel inhibitors with greater selectivity. Molecular Operating Environment (MOE) software was used to build a homology model for P. mirabilis MetRS using Escherichia coli MetRS as a template. The model was evaluated, and the active site of the target protein predicted from its sequence using conservation analysis. Molecular dynamic simulations were performed to evaluate the stability of the modeled protein structure. In order to evaluate the predicted active site interactions, methionine (the natural substrate of MetRS) and several inhibitors of bacterial MetRS were docked into the constructed model using MOE. After validation of the model, pharmacophore-based virtual screening for a systemically prepared dataset of compounds was performed to prove the feasibility of the proposed model, identifying possible parent compounds for further development of MetRS inhibitors against P. mirabilis.
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Affiliation(s)
- Samar S. Elbaramawi
- Department of Medicinal Chemistry, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt; (S.S.E.); (A.G.E.); (N.A.N.)
| | - Ahmed G. Eissa
- Department of Medicinal Chemistry, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt; (S.S.E.); (A.G.E.); (N.A.N.)
| | - Nada A. Noureldin
- Department of Medicinal Chemistry, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt; (S.S.E.); (A.G.E.); (N.A.N.)
| | - Claire Simons
- School of Pharmacy & Pharmaceutical Sciences, Cardiff University, King Edward VII Avenue, Cardiff CF10 3NB, UK
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4
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El‐Shahat M. Advances in the reduction of quinolines to 1,2,3,4‐tetrahydroquinolines. J Heterocycl Chem 2021. [DOI: 10.1002/jhet.4394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Mahmoud El‐Shahat
- Photochemistry Department Chemical Industries Research Institute, National Research Centre, Scopus affiliation ID 60014618 Giza Egypt
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5
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Mercaldi GF, Andrade MDO, Zanella JDL, Cordeiro AT, Benedetti CE. Molecular basis for diaryldiamine selectivity and competition with tRNA in a type 2 methionyl-tRNA synthetase from a Gram-negative bacterium. J Biol Chem 2021; 296:100658. [PMID: 33857480 PMCID: PMC8165550 DOI: 10.1016/j.jbc.2021.100658] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 04/06/2021] [Accepted: 04/09/2021] [Indexed: 12/20/2022] Open
Abstract
Gram-negative bacteria are responsible for a variety of human, animal, and plant diseases. The spread of multidrug-resistant Gram-negative bacteria poses a challenge to disease control and highlights the need for novel antimicrobials. Owing to their critical role in protein synthesis, aminoacyl-tRNA synthetases, including the methionyl-tRNA synthetases MetRS1 and MetRS2, are attractive drug targets. MetRS1 has long been exploited as a drug target in Gram-positive bacteria and protozoan parasites. However, MetRS1 inhibitors have limited action upon Gram-negative pathogens or on Gram-positive bacteria that produce MetRS2 enzymes. The underlying mechanism by which MetRS2 enzymes are insensitive to MetRS1 inhibitors is presently unknown. Herein, we report the first structures of MetRS2 from a multidrug-resistant Gram-negative bacterium in its ligand-free state and bound to its substrate or MetRS1 inhibitors. The structures reveal the binding mode of two diaryldiamine MetRS1 inhibitors that occupy the amino acid-binding site and a surrounding auxiliary pocket implicated in tRNA acceptor arm binding. The structural features associated with amino acid polymorphisms found in the methionine and auxiliary pockets reveal the molecular basis for diaryldiamine binding and selectivity between MetRS1 and MetRS2 enzymes. Moreover, we show that mutations in key polymorphic residues in the methionine and auxiliary pockets not only altered inhibitor binding affinity but also significantly reduced enzyme function. Our findings thus reinforce the tRNA acceptor arm binding site as a druggable pocket in class I aminoacyl-tRNA synthetases and provide a structural basis for optimization of MetRS2 inhibitors for the development of new antimicrobials against Gram-negative pathogens.
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Affiliation(s)
- Gustavo Fernando Mercaldi
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Centre for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil.
| | - Maxuel de Oliveira Andrade
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Centre for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil
| | - Jackeline de Lima Zanella
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Centre for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil
| | - Artur Torres Cordeiro
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Centre for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil
| | - Celso Eduardo Benedetti
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Centre for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil.
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6
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Farooq S, Mazhar A, Ghouri A, Ullah N. One-Pot Multicomponent Synthesis and Bioevaluation of Tetrahydroquinoline Derivatives as Potential Antioxidants, α-Amylase Enzyme Inhibitors, Anti-Cancerous and Anti-Inflammatory Agents. Molecules 2020; 25:molecules25112710. [PMID: 32545290 PMCID: PMC7321408 DOI: 10.3390/molecules25112710] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/05/2020] [Accepted: 06/07/2020] [Indexed: 11/16/2022] Open
Abstract
Mankind has always suffered from multiple diseases. Therefore, there has been a rigorous need in the field of medicinal chemistry for the design and discovery of new and potent molecular entities. In this work, thirteen tetrahydroquinoline derivatives were synthesized and evaluated biologically for their antioxidant, α-amylase enzyme inhibitory, anti-proliferative and anti-inflammatory activities. SF8 showed the lowest IC50 of 29.19 ± 0.25 µg/mL by scavenging DPPH free radicals. SF5 showed significant antioxidant activity in total antioxidant capacity (TAC) and total reducing power (TRP) assays. SF5 and SF9 showed the maximum inhibition of α-amylase enzyme i.e., 97.47% and 89.93%, respectively, at 200 µg/mL concentration. Five compounds were shortlisted to determine their anti-proliferative potential against Hep-2C cells. The study was conducted for 24, 48 and 72 h. SF8 showed significant results, having an IC50 value of 11.9 ± 1.04 µM at 72 h when compared with standard cisplatin (IC50 value of 14.6 ± 1.01 µM). An in vitro nitric oxide (NO) assay was performed to select compounds for in vivo anti-inflammatory activity evaluation. SF13 scavenged the NO level to a maximum of 85% at 50 µM concentration, followed by SF1 and SF2. Based on the NO scavenging assay results, in vivo anti-inflammatory studies were also performed and the results showed significant activity compared to the standard, acetylsalicylic acid (ASA).
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7
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Zhang Z, Barros-Álvarez X, Gillespie JR, Ranade RM, Huang W, Shibata S, Molasky NMR, Faghih O, Mushtaq A, Choy RKM, de Hostos E, Hol WGJ, Verlinde CLMJ, Buckner FS, Fan E. Structure-guided discovery of selective methionyl-tRNA synthetase inhibitors with potent activity against Trypanosoma brucei. RSC Med Chem 2020; 11:885-895. [PMID: 33479683 DOI: 10.1039/d0md00057d] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 04/21/2020] [Indexed: 12/25/2022] Open
Abstract
Based on crystal structures of Trypanosoma brucei methionyl-tRNA synthetase (TbMetRS) bound to inhibitors, we designed, synthesized, and evaluated two series of novel TbMetRS inhibitors targeting this parasite enzyme. One series has a 1,3-dihydro-imidazol-2-one containing linker, the other has a rigid fused aromatic ring in the linker. For both series of compounds, potent inhibition of parasite growth was achieved with EC50 < 10 nM and most compounds exhibited low general toxicity to mammalian cells with CC50s > 20 000 nM. Selectivity over human mitochondrial methionyl tRNA synthetase was also evaluated, using a cell-based mitochondrial protein synthesis assay, and selectivity in a range of 20-200-fold was achieved. The inhibitors exhibited poor permeability across the blood brain barrier, necessitating future efforts to optimize the compounds for use in late stage human African trypanosomiasis.
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Affiliation(s)
- Zhongsheng Zhang
- Department of Biochemistry , University of Washington , Seattle , WA 98195 , USA .
| | | | - J Robert Gillespie
- Department of Medicine , Division of Allergy & Infectious Disease , Center for Emerging & Re-emerging Infectious Disease (CERID) , University of Washington , Seattle , WA 98109 , USA .
| | - Ranae M Ranade
- Department of Medicine , Division of Allergy & Infectious Disease , Center for Emerging & Re-emerging Infectious Disease (CERID) , University of Washington , Seattle , WA 98109 , USA .
| | - Wenlin Huang
- Department of Biochemistry , University of Washington , Seattle , WA 98195 , USA .
| | - Sayaka Shibata
- Department of Biochemistry , University of Washington , Seattle , WA 98195 , USA .
| | - Nora M R Molasky
- Department of Medicine , Division of Allergy & Infectious Disease , Center for Emerging & Re-emerging Infectious Disease (CERID) , University of Washington , Seattle , WA 98109 , USA .
| | - Omeed Faghih
- Department of Medicine , Division of Allergy & Infectious Disease , Center for Emerging & Re-emerging Infectious Disease (CERID) , University of Washington , Seattle , WA 98109 , USA .
| | - Aisha Mushtaq
- Department of Medicine , Division of Allergy & Infectious Disease , Center for Emerging & Re-emerging Infectious Disease (CERID) , University of Washington , Seattle , WA 98109 , USA .
| | | | | | - Wim G J Hol
- Department of Biochemistry , University of Washington , Seattle , WA 98195 , USA .
| | | | - Frederick S Buckner
- Department of Medicine , Division of Allergy & Infectious Disease , Center for Emerging & Re-emerging Infectious Disease (CERID) , University of Washington , Seattle , WA 98109 , USA .
| | - Erkang Fan
- Department of Biochemistry , University of Washington , Seattle , WA 98195 , USA .
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8
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Vasconcelos Vontobel PH, Dos Santos Fuscaldo R, Dos Santos FP, Sobieski da Costa J. Regioselective preparation and NMR spectroscopy study of 2-chloro-4-ethoxy-quinoline for the synthesis of 2-((3-aminopropyl)amino)quinolin-4(1H)-one. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2020; 58:295-304. [PMID: 31828850 DOI: 10.1002/mrc.4980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 12/02/2019] [Accepted: 12/04/2019] [Indexed: 06/10/2023]
Abstract
Herein, we describe the C4-ethoxylation of 2,4-dichloroquinoline to prepare 2-chloro-4-ethoxy-quinoline (3), which is a prominent intermediate used for the synthesis of 2-substituted quinolones. To achieve this goal, we studied different conditions for the reaction between 2,4-dichloroquinoline and sodium ethoxide. We discovered that the use of 18-crown-6 ether as an additive and dimethylformamide as the reaction solvent allowed us to obtain the desired product 3 in very good yield and selectivity. In addition, a definitive distinction between the C2 and C4 ethoxylation products was achieved using 1 H─15 N heteronuclear multiple bond correlation. Compound 3 is an intermediate used for the synthesis of 2-((3-aminopropyl)amino)quinolin-4(1H)-one, which displays peculiar behavior during 1 H nuclear magnetic resonance analysis, such as the broadening of the H8 singlet and unexpected deuteration at the C8-position. Effort has been dedicated to understand these findings.
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9
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Rezende TRM, Varejão JOS, Sousa ALLDA, Castañeda SMB, Fernandes SA. Tetrahydroquinolines by the multicomponent Povarov reaction in water: calix[n]arene-catalysed cascade process and mechanistic insights. Org Biomol Chem 2019; 17:2913-2922. [DOI: 10.1039/c8ob02928h] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new calixarene-catalyzed cascade process, via the Povarov reaction, for the synthesis of tetrahydroquinolines is described, and the proposed reaction mechanism was validated.
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10
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Application of a catalyst-free Domino Mannich/Friedel-Crafts alkylation reaction for the synthesis of novel tetrahydroquinolines of potential antitumor activity. Tetrahedron 2018. [DOI: 10.1016/j.tet.2017.12.049] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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11
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Development of Methionyl-tRNA Synthetase Inhibitors as Antibiotics for Gram-Positive Bacterial Infections. Antimicrob Agents Chemother 2017; 61:AAC.00999-17. [PMID: 28848016 DOI: 10.1128/aac.00999-17] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 08/22/2017] [Indexed: 01/17/2023] Open
Abstract
Antibiotic-resistant bacteria are widespread and pose a growing threat to human health. New antibiotics acting by novel mechanisms of action are needed to address this challenge. The bacterial methionyl-tRNA synthetase (MetRS) enzyme is essential for protein synthesis, and the type found in Gram-positive bacteria is substantially different from its counterpart found in the mammalian cytoplasm. Both previously published and new selective inhibitors were shown to be highly active against Gram-positive bacteria with MICs of ≤1.3 μg/ml against Staphylococcus, Enterococcus, and Streptococcus strains. Incorporation of radioactive precursors demonstrated that the mechanism of activity was due to the inhibition of protein synthesis. Little activity against Gram-negative bacteria was observed, consistent with the fact that Gram-negative bacterial species contain a different type of MetRS enzyme. The ratio of the MIC to the minimum bactericidal concentration (MBC) was consistent with a bacteriostatic mechanism. The level of protein binding of the compounds was high (>95%), and this translated to a substantial increase in MICs when the compounds were tested in the presence of serum. Despite this, the compounds were very active when they were tested in a Staphylococcus aureus murine thigh infection model. Compounds 1717 and 2144, given by oral gavage, resulted in 3- to 4-log decreases in the bacterial load compared to that in vehicle-treated mice, which was comparable to the results observed with the comparator drugs, vancomycin and linezolid. In summary, the research describes MetRS inhibitors with oral bioavailability that represent a class of compounds acting by a novel mechanism with excellent potential for clinical development.
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12
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Huang W, Zhang Z, Ranade RM, Gillespie JR, Barros-Álvarez X, Creason SA, Shibata S, Verlinde CLMJ, Hol WGJ, Buckner FS, Fan E. Optimization of a binding fragment targeting the "enlarged methionine pocket" leads to potent Trypanosoma brucei methionyl-tRNA synthetase inhibitors. Bioorg Med Chem Lett 2017; 27:2702-2707. [PMID: 28465105 DOI: 10.1016/j.bmcl.2017.04.048] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 04/14/2017] [Indexed: 11/18/2022]
Abstract
Potent inhibitors of Trypanosoma brucei methionyl-tRNA synthetase were previously designed using a structure-guided approach. Compounds 1 and 2 were the most active compounds in the cyclic and linear linker series, respectively. To further improve cellular potency, SAR investigation of a binding fragment targeting the "enlarged methionine pocket" (EMP) was performed. The optimization led to the identification of a 6,8-dichloro-tetrahydroquinoline ring as a favorable fragment to bind the EMP. Replacement of 3,5-dichloro-benzyl group (the EMP binding fragment) of inhibitor 2 using this tetrahydroquinoline fragment resulted in compound 13, that exhibited an EC50 of 4nM.
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Affiliation(s)
- Wenlin Huang
- Department of Biochemistry, University of Washington, Seattle, WA 98195, United States
| | - Zhongsheng Zhang
- Department of Biochemistry, University of Washington, Seattle, WA 98195, United States
| | - Ranae M Ranade
- Department of Medicine, Division of Allergy and Infectious Diseases, and the Center for Emerging and Re-emerging Infectious Diseases (CERID), University of Washington, Seattle, WA 98109, United States
| | - J Robert Gillespie
- Department of Medicine, Division of Allergy and Infectious Diseases, and the Center for Emerging and Re-emerging Infectious Diseases (CERID), University of Washington, Seattle, WA 98109, United States
| | - Ximena Barros-Álvarez
- Department of Biochemistry, University of Washington, Seattle, WA 98195, United States; Laboratorio de Enzimología de Parásitos, Facultad de Ciencias, Universidad de los Andes, Mérida, Venezuela
| | - Sharon A Creason
- Department of Medicine, Division of Allergy and Infectious Diseases, and the Center for Emerging and Re-emerging Infectious Diseases (CERID), University of Washington, Seattle, WA 98109, United States
| | - Sayaka Shibata
- Department of Biochemistry, University of Washington, Seattle, WA 98195, United States
| | | | - Wim G J Hol
- Department of Biochemistry, University of Washington, Seattle, WA 98195, United States
| | - Frederick S Buckner
- Department of Medicine, Division of Allergy and Infectious Diseases, and the Center for Emerging and Re-emerging Infectious Diseases (CERID), University of Washington, Seattle, WA 98109, United States.
| | - Erkang Fan
- Department of Biochemistry, University of Washington, Seattle, WA 98195, United States.
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13
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Huang W, Zhang Z, Barros-Álvarez X, Koh CY, Ranade RM, Gillespie JR, Creason SA, Shibata S, Verlinde CLMJ, Hol WGJ, Buckner FS, Fan E. Structure-guided design of novel Trypanosoma brucei Methionyl-tRNA synthetase inhibitors. Eur J Med Chem 2016; 124:1081-1092. [PMID: 27788467 DOI: 10.1016/j.ejmech.2016.10.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 09/29/2016] [Accepted: 10/13/2016] [Indexed: 02/07/2023]
Abstract
A screening hit 1 against Trypanosoma brucei methionyl-tRNA synthetase was optimized using a structure-guided approach. The optimization led to the identification of two novel series of potent inhibitors, the cyclic linker and linear linker series. Compounds of both series were potent in a T. brucei growth inhibition assay while showing low toxicity to mammalian cells. The best compound of each series, 16 and 31, exhibited EC50s of 39 and 22 nM, respectively. Compounds 16 and 31 also exhibited promising PK properties after oral dosing in mice. Moreover, compound 31 had moderately good brain permeability, with a brain/plasma ratio of 0.27 at 60 min after IP injection. This study provides new lead compounds for arriving at new treatments of human African trypanosomiasis (HAT).
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Affiliation(s)
- Wenlin Huang
- Department of Biochemistry, University of Washington, Seattle, WA 98195, United States
| | - Zhongsheng Zhang
- Department of Biochemistry, University of Washington, Seattle, WA 98195, United States
| | - Ximena Barros-Álvarez
- Department of Biochemistry, University of Washington, Seattle, WA 98195, United States; Laboratorio de Enzimología de Parásitos, Facultad de Ciencias, Universidad de los Andes, Mérida, Venezuela
| | - Cho Yeow Koh
- Department of Biochemistry, University of Washington, Seattle, WA 98195, United States
| | - Ranae M Ranade
- Department of Medicine, Division of Allergy and Infectious Diseases, and the Center for Emerging and Re-emerging Infectious Diseases (CERID), University of Washington, Seattle, WA 98109, United States
| | - J Robert Gillespie
- Department of Medicine, Division of Allergy and Infectious Diseases, and the Center for Emerging and Re-emerging Infectious Diseases (CERID), University of Washington, Seattle, WA 98109, United States
| | - Sharon A Creason
- Department of Medicine, Division of Allergy and Infectious Diseases, and the Center for Emerging and Re-emerging Infectious Diseases (CERID), University of Washington, Seattle, WA 98109, United States
| | - Sayaka Shibata
- Department of Biochemistry, University of Washington, Seattle, WA 98195, United States
| | | | - Wim G J Hol
- Department of Biochemistry, University of Washington, Seattle, WA 98195, United States
| | - Frederick S Buckner
- Department of Medicine, Division of Allergy and Infectious Diseases, and the Center for Emerging and Re-emerging Infectious Diseases (CERID), University of Washington, Seattle, WA 98109, United States.
| | - Erkang Fan
- Department of Biochemistry, University of Washington, Seattle, WA 98195, United States.
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14
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Rational design, synthesis, anti-HIV-1 RT and antimicrobial activity of novel 3-(6-methoxy-3,4-dihydroquinolin-1(2H)-yl)-1-(piperazin-1-yl)propan-1-one derivatives. Bioorg Chem 2016; 67:75-83. [DOI: 10.1016/j.bioorg.2016.05.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 05/29/2016] [Accepted: 05/31/2016] [Indexed: 11/18/2022]
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15
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Lei P, Zhang X, Xu Y, Xu G, Liu X, Yang X, Zhang X, Ling Y. Synthesis and fungicidal activity of pyrazole derivatives containing 1,2,3,4-tetrahydroquinoline. Chem Cent J 2016; 10:40. [PMID: 27382411 PMCID: PMC4932680 DOI: 10.1186/s13065-016-0186-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 06/20/2016] [Indexed: 12/02/2022] Open
Abstract
Background Take-all of wheat, caused by the soil-borne fungus Gaeumannomyces graminis var. tritici, is one of the most important and widespread root diseases. Given that take-all is still hard to control, it is necessary to develop new effective agrochemicals. Pyrazole derivatives have been often reported for their favorable bioactivities. In order to discover compounds with high fungicidal activity and simple structures, 1,2,3,4-tetrahydroquinoline, a biologically active group of natural products, was introduced to pyrazole structure. A series of pyrazole derivatives containing 1,2,3,4-tetrahydroquinoline were synthesized, and their fungicidal activities were evaluated. Results The bioassay results demonstrated that the title compounds displayed obvious fungicidal activities at a concentration of 50 μg/mL, especially against V. mali, S. sclerotiorum and G. graminis var. tritici. The inhibition rates of compounds 10d, 10e, 10h, 10i and 10j against G. graminis var. tritici were all above 90 %. Even at a lower concentration of 16.7 μg/mL, compounds 10d and 10e exhibited satisfied activities of 100 % and 94.0 %, respectively. It is comparable to that of the positive control pyraclostrobin with 100 % inhibition rate. Conclusion A series of pyrazole derivatives containing 1,2,3,4-tetrahydroquinoline were synthesized and their structures were confirmed by 1H NMR, 13C NMR, IR spectrum and HRMS or elemental analysis. The crystal structure of compound 10g was confirmed by X-ray diffraction. Bioassay results indicated that all title compounds exhibited obvious fungicidal activities. In particular, compounds 10d and 10e showed comparable activities against G. graminis var. tritici with the commercial fungicide pyraclostrobin at the concentration of 16.7 μg/mL.A series of pyrazole derivatives containing 1,2,3,4-tetrahydroquinoline were designed and synthesized. Bioassay results indicated that all these compounds exhibited obvious fungicidal activities. ![]() Electronic supplementary material The online version of this article (doi:10.1186/s13065-016-0186-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Peng Lei
- Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, 100193 China
| | - Xuebo Zhang
- Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, 100193 China
| | - Yan Xu
- Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, 100193 China
| | - Gaofei Xu
- Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, 100193 China
| | - Xili Liu
- Department of Plant Pathology, China Agricultural University, Beijing, 100193 China
| | - Xinling Yang
- Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, 100193 China
| | - Xiaohe Zhang
- Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, 100193 China
| | - Yun Ling
- Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, 100193 China
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16
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Zhang Z, Koh CY, Ranade RM, Shibata S, Gillespie JR, Hulverson MA, Huang W, Nguyen J, Pendem N, Gelb MH, Verlinde CLMJ, Hol WGJ, Buckner FS, Fan E. 5-Fluoroimidazo[4,5-b]pyridine Is a Privileged Fragment That Conveys Bioavailability to Potent Trypanosomal Methionyl-tRNA Synthetase Inhibitors. ACS Infect Dis 2016; 2:399-404. [PMID: 27627628 PMCID: PMC5108244 DOI: 10.1021/acsinfecdis.6b00036] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
![]()
Fluorination
is a well-known strategy for improving the bioavailability of drug
molecules. However, its impact on efficacy is not easily predicted.
On the basis of inhibitor-bound protein crystal structures, we found
a beneficial fluorination spot for inhibitors targeting methionyl-tRNA
synthetase of Trypanosoma brucei. In
particular, incorporating 5-fluoroimidazo[4,5-b]pyridine
into inhibitors leads to central nervous system bioavailability and
maintained or even improved efficacy.
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Affiliation(s)
- Zhongsheng Zhang
- Department of Biochemistry, University of Washington, 1705 N.E. Pacific Street, Seattle, Washington 98195, United States
| | - Cho Yeow Koh
- Department of Biochemistry, University of Washington, 1705 N.E. Pacific Street, Seattle, Washington 98195, United States
| | - Ranae M. Ranade
- Department of Medicine, Division of Allergy
and Infectious Diseases, and the Center for Emerging and Re-emerging
Infectious Diseases (CERID), University of Washington, 750 Republican
Street, Seattle, Washington 98109, United States
| | - Sayaka Shibata
- Department of Biochemistry, University of Washington, 1705 N.E. Pacific Street, Seattle, Washington 98195, United States
| | - J. Robert Gillespie
- Department of Medicine, Division of Allergy
and Infectious Diseases, and the Center for Emerging and Re-emerging
Infectious Diseases (CERID), University of Washington, 750 Republican
Street, Seattle, Washington 98109, United States
| | - Matthew A. Hulverson
- Department of Medicine, Division of Allergy
and Infectious Diseases, and the Center for Emerging and Re-emerging
Infectious Diseases (CERID), University of Washington, 750 Republican
Street, Seattle, Washington 98109, United States
| | - Wenlin Huang
- Department of Biochemistry, University of Washington, 1705 N.E. Pacific Street, Seattle, Washington 98195, United States
| | - Jasmine Nguyen
- Department of Biochemistry, University of Washington, 1705 N.E. Pacific Street, Seattle, Washington 98195, United States
| | - Nagendar Pendem
- Department of Chemistry, Bagley Hall, University of Washington, Seattle, Washington 98195, United States
| | - Michael H. Gelb
- Department of Chemistry, Bagley Hall, University of Washington, Seattle, Washington 98195, United States
| | - Christophe L. M. J. Verlinde
- Department of Biochemistry, University of Washington, 1705 N.E. Pacific Street, Seattle, Washington 98195, United States
| | - Wim G. J. Hol
- Department of Biochemistry, University of Washington, 1705 N.E. Pacific Street, Seattle, Washington 98195, United States
| | - Frederick S. Buckner
- Department of Medicine, Division of Allergy
and Infectious Diseases, and the Center for Emerging and Re-emerging
Infectious Diseases (CERID), University of Washington, 750 Republican
Street, Seattle, Washington 98109, United States
| | - Erkang Fan
- Department of Biochemistry, University of Washington, 1705 N.E. Pacific Street, Seattle, Washington 98195, United States
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17
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Chen C, Zingales S, Wang T, Yuan M, Wang D, Cai L, Jiang Q. Synthesis and in vitro evaluation of 4-substituted furano[3,2-c] tetrahydroquinolines as potential anti-cancer agents. J Enzyme Inhib Med Chem 2015. [PMID: 26207511 DOI: 10.3109/14756366.2015.1064120] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Can Chen
- College of Pharmacy and the First Affiliated Hospital, Chengdu Medical College, Chengdu, PR China
- Department of Pharmacy, Sichuan Provincial People’s Hospital, Chengdu, PR China
| | - Sarah Zingales
- Department of Chemistry, Armstrong State University, Savannah, GA, USA, and
| | - Ting Wang
- Department of Cardiology, General Hospital of Chengdu Military Command, Chengdu, PR China
| | - Mingyong Yuan
- College of Pharmacy and the First Affiliated Hospital, Chengdu Medical College, Chengdu, PR China
| | - Dan Wang
- College of Pharmacy and the First Affiliated Hospital, Chengdu Medical College, Chengdu, PR China
| | - Lulu Cai
- Department of Pharmacy, Sichuan Provincial People’s Hospital, Chengdu, PR China
| | - Qinglin Jiang
- College of Pharmacy and the First Affiliated Hospital, Chengdu Medical College, Chengdu, PR China
- Department of Cardiology, General Hospital of Chengdu Military Command, Chengdu, PR China
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18
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Abstract
Transfer RNAs (tRNAs) are central players in the protein translation machinery and as such are prominent targets for a large number of natural and synthetic antibiotics. This review focuses on the role of tRNAs in bacterial antibiosis. We will discuss examples of antibiotics that target multiple stages in tRNA biology from tRNA biogenesis and modification, mature tRNAs, aminoacylation of tRNA as well as prevention of proper tRNA function by small molecules binding to the ribosome. Finally, the role of deacylated tRNAs in the bacterial “stringent response” mechanism that can lead to bacteria displaying antibiotic persistence phenotypes will be discussed.
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19
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Shinozuka T, Saito K, Naito S. An Efficient Method for the Preparation of 4-Alkoxy-substituted Thieno[2,3-b]pyridines. HETEROCYCLES 2014. [DOI: 10.3987/com-14-12986] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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20
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21
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Pandit RP, Lee YR. Efficient one-pot synthesis of novel and diverse tetrahydroquinolines bearing pyranopyrazoles using organocatalyzed domino Knoevenagel/hetero Diels-Alder reactions. Mol Divers 2013; 18:39-50. [PMID: 24057164 DOI: 10.1007/s11030-013-9482-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 09/01/2013] [Indexed: 11/29/2022]
Abstract
A new synthetic route to biologically interesting diverse tetrahydroquinolines bearing pyranopyrazoles was developed by reacting pyrazolones and N, N-dialkylated aminobenzaldehydes in the presence of EDDA. The key strategy underlying the methodology used was the domino Knoevenagel/hetero Diels-Alder reaction. This synthetic method provides a variety of novel tetrahydroquinolines in good yields.
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22
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Bondalapati S, Indukuri K, Ghosh P, Saikia AK. Stereoselective Synthesis of Tetrahydroquinolines Through an Imino-Ene Cyclization Reaction. European J Org Chem 2013. [DOI: 10.1002/ejoc.201201363] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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23
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Koh CY, Kim JE, Shibata S, Ranade RM, Yu M, Liu J, Gillespie JR, Buckner FS, Verlinde CL, Fan E, Hol WG. Distinct states of methionyl-tRNA synthetase indicate inhibitor binding by conformational selection. Structure 2012; 20:1681-91. [PMID: 22902861 PMCID: PMC3472110 DOI: 10.1016/j.str.2012.07.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Revised: 07/18/2012] [Accepted: 07/20/2012] [Indexed: 02/07/2023]
Abstract
To guide development of new drugs targeting methionyl-tRNA synthetase (MetRS) for treatment of human African trypanosomiasis, crystal structure determinations of Trypanosoma brucei MetRS in complex with its substrate methionine and its intermediate product methionyl-adenylate were followed by those of the enzyme in complex with high-affinity aminoquinolone inhibitors via soaking experiments. Drastic changes in conformation of one of the two enzymes in the asymmetric unit allowed these inhibitors to occupy an enlarged methionine pocket and a new so-called auxiliary pocket. Interestingly, a small low-affinity compound caused the same conformational changes, removed the methionine without occupying the methionine pocket, and occupied the previously not existing auxiliary pocket. Analysis of these structures indicates that the binding of the inhibitors is the result of conformational selection, not induced fit.
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Affiliation(s)
- Cho Yeow Koh
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | - Jessica E. Kim
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | - Sayaka Shibata
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA,Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
| | - Ranae M. Ranade
- Department of Medicine, University of Washington, Seattle, Washington 98195, USA
| | - Mingyan Yu
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA,Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Shandong University, No. 44 Wenhuaxi Road, Jinan 250012, P.R. China
| | - Jiyun Liu
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | - J. Robert Gillespie
- Department of Medicine, University of Washington, Seattle, Washington 98195, USA
| | - Frederick S. Buckner
- Department of Medicine, University of Washington, Seattle, Washington 98195, USA
| | | | - Erkang Fan
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | - Wim G.J. Hol
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA,Correspondence to:
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24
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Shibata S, Gillespie JR, Ranade RM, Koh CY, Kim JE, Laydbak JU, Zucker FH, Hol WGJ, Verlinde CLMJ, Buckner FS, Fan E. Urea-based inhibitors of Trypanosoma brucei methionyl-tRNA synthetase: selectivity and in vivo characterization. J Med Chem 2012; 55:6342-51. [PMID: 22720744 DOI: 10.1021/jm300303e] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Urea-based methionyl-tRNA synthetase inhibitors were designed, synthesized, and evaluated for their potential toward treating human African trypanosomiasis (HAT). With the aid of a homology model and a structure-activity-relationship approach, low nM inhibitors were discovered that show high selectivity toward the parasite enzyme over the closest human homologue. These compounds inhibit parasite growth with EC(50) values as low as 0.15 μM while having low toxicity to mammalian cells. Two compounds (2 and 26) showed excellent membrane permeation in the MDR1-MDCKII model and encouraging oral pharmacokinetic properties in mice. Compound 2 was confirmed to enter the CNS in mice. Compound 26 had modest suppressive activity against Trpanosoma brucei rhodesiense in the mouse model, suggesting that more potent analogues or compounds with higher exposures need to be developed. The urea-based inhibitors are thus a promising starting point for further optimization toward the discovery of orally available and CNS active drugs to treat HAT.
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Affiliation(s)
- Sayaka Shibata
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
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25
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Sridharan V, Suryavanshi PA, Menéndez JC. Advances in the chemistry of tetrahydroquinolines. Chem Rev 2011; 111:7157-259. [PMID: 21830756 DOI: 10.1021/cr100307m] [Citation(s) in RCA: 765] [Impact Index Per Article: 58.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Vellaisamy Sridharan
- Departamento de Química Orgánica y Farmacéutica, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
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26
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Larson ET, Kim JE, Zucker FH, Kelley A, Mueller N, Napuli AJ, Verlinde CL, Fan E, Buckner FS, Van Voorhis WC, Merritt EA, Hol WG. Structure of Leishmania major methionyl-tRNA synthetase in complex with intermediate products methionyladenylate and pyrophosphate. Biochimie 2011; 93:570-82. [PMID: 21144880 PMCID: PMC3039092 DOI: 10.1016/j.biochi.2010.11.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 11/29/2010] [Indexed: 01/07/2023]
Abstract
Leishmania parasites cause two million new cases of leishmaniasis each year with several hundreds of millions of people at risk. Due to the paucity and shortcomings of available drugs, we have undertaken the crystal structure determination of a key enzyme from Leishmania major in hopes of creating a platform for the rational design of new therapeutics. Crystals of the catalytic core of methionyl-tRNA synthetase from L. major (LmMetRS) were obtained with the substrates MgATP and methionine present in the crystallization medium. These crystals yielded the 2.0 Å resolution structure of LmMetRS in complex with two products, methionyladenylate and pyrophosphate, along with a Mg(2+) ion that bridges them. This is the first class I aminoacyl-tRNA synthetase (aaRS) structure with pyrophosphate bound. The residues of the class I aaRS signature sequence motifs, KISKS and HIGH, make numerous contacts with the pyrophosphate. Substantial differences between the LmMetRS structure and previously reported complexes of Escherichia coli MetRS (EcMetRS) with analogs of the methionyladenylate intermediate product are observed, even though one of these analogs only differs by one atom from the intermediate. The source of these structural differences is attributed to the presence of the product pyrophosphate in LmMetRS. Analysis of the LmMetRS structure in light of the Aquifex aeolicus MetRS-tRNA(Met) complex shows that major rearrangements of multiple structural elements of enzyme and/or tRNA are required to allow the CCA acceptor triplet to reach the methionyladenylate intermediate in the active site. Comparison with sequences of human cytosolic and mitochondrial MetRS reveals interesting differences near the ATP- and methionine-binding regions of LmMetRS, suggesting that it should be possible to obtain compounds that selectively inhibit the parasite enzyme.
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Affiliation(s)
- Eric T. Larson
- Department of Biochemistry, University of Washington, Seattle, WA 98195-7742, USA,Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org
| | - Jessica E. Kim
- Department of Biochemistry, University of Washington, Seattle, WA 98195-7742, USA,Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org
| | - Frank H. Zucker
- Department of Biochemistry, University of Washington, Seattle, WA 98195-7742, USA,Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org
| | - Angela Kelley
- Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org,Department of Medicine, University of Washington, Seattle, WA 98195-7185, USA
| | - Natascha Mueller
- Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org,Department of Medicine, University of Washington, Seattle, WA 98195-7185, USA
| | - Alberto J. Napuli
- Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org,Department of Medicine, University of Washington, Seattle, WA 98195-7185, USA
| | - Christophe L.M.J. Verlinde
- Department of Biochemistry, University of Washington, Seattle, WA 98195-7742, USA,Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org
| | - Erkang Fan
- Department of Biochemistry, University of Washington, Seattle, WA 98195-7742, USA,Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org
| | - Frederick S. Buckner
- Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org,Department of Medicine, University of Washington, Seattle, WA 98195-7185, USA
| | - Wesley C. Van Voorhis
- Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org,Department of Medicine, University of Washington, Seattle, WA 98195-7185, USA
| | - Ethan A. Merritt
- Department of Biochemistry, University of Washington, Seattle, WA 98195-7742, USA,Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org
| | - Wim G.J. Hol
- Department of Biochemistry, University of Washington, Seattle, WA 98195-7742, USA,Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org,Corresponding author.
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27
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Liu Y, Zhang W, Sayre LM. A straightforward synthesis of pentosidine framework. J Heterocycl Chem 2010. [DOI: 10.1002/jhet.374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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28
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Synthesis, ring transformations, IR-, NMR and DFT study of heterocycles with two ferrocenyl units. J Organomet Chem 2009. [DOI: 10.1016/j.jorganchem.2009.07.038] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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29
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2-Aminobenzimidazoles as potent Aurora kinase inhibitors. Bioorg Med Chem Lett 2009; 19:5158-61. [DOI: 10.1016/j.bmcl.2009.07.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Revised: 06/28/2009] [Accepted: 07/02/2009] [Indexed: 12/17/2022]
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30
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Faqi AS, Bell SJ, Gill S, Colagiovanni DB. An intranasal irritation assessment of antibacterial ointment alone or in combination with mupirocin versus Bactroban Nasal in rabbits. Regul Toxicol Pharmacol 2009; 55:28-32. [PMID: 19497343 DOI: 10.1016/j.yrtph.2009.05.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Revised: 05/26/2009] [Accepted: 05/27/2009] [Indexed: 10/20/2022]
Abstract
The purpose of this study was to evaluate the potential irritating effects and the systemic exposure level of an antibacterial ointment containing REP8839 as a single agent or in combination with mupirocin versus Bactroban Nasal in rabbits. Additionally, the reversibility of REP8839 effects during a 14-day recovery period was assessed. Five treatment groups of six male and six female New Zealand White rabbits received dose levels of 1%, 2%, and 4% REP8839, 2% Bactroban Nasal, or 2% REP8839/2% mupirocin combination. One additional group of six animals/sex served as the control and received the vehicle, Petrolatum/Softisan 649. The test article or vehicle was administered to all groups via topical administration to the external nares, twice a day (approx. 8h intervals between the doses) for 21 consecutive days, at a dose volume of 100 microL per nare/dose for a total of 400 microL per day (200 microL per nare). Two animals/sex/group were maintained for a 14-day recovery period. The external nares were reflected back and the mucosal lining was evaluated and scored for erythema and edema within 30-60 min following the first dose each day. Blood samples were collected from all animals at designated time points on Day 21 of the study to assess systemic exposure levels. Cross-sectioning of the nasal tract was conducted in all the groups for microscopic evaluation. Mucosal scoring of the nares did not reveal any edema or erythema in any of the dose groups with the antibacterial alone, with the combination product, or with Bactroban Nasal. Mean body weights and food consumption were not adversely impacted by the test articles. Minimal plasma exposure was observed in the rabbits (<5 ng/mL). The REP8839 groups did appear to have dose-responsive exposure (from below the limit of quantitation to 5 ng/mL with 1%, 2%, and 4% REP8839, respectively). Microscopic changes on the nasal sectioning noted in these animals were infrequent and considered incidental findings unrelated to administration of the test articles. In conclusion doses of up to 4% of REP8839 ointment as a single agent or 2% in the combination product, as well as 2% Bactroban Nasal, were not found to induce mucosal irritation when applied topically to the external nares twice a day for 21 consecutive days. Additionally, no delayed effects were observed in the recovery animals.
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Affiliation(s)
- Ali S Faqi
- MPI Research, 4943 Main Street, Mattawan, MI 49071, USA.
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31
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Search for inhibitors of AminoAcyl-tRNA synthases by virtual click chemistry. J Mol Model 2008; 15:665-72. [DOI: 10.1007/s00894-008-0421-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Accepted: 11/07/2008] [Indexed: 11/30/2022]
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32
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Critchley IA, Ochsner UA. Recent advances in the preclinical evaluation of the topical antibacterial agent REP8839. Curr Opin Chem Biol 2008; 12:409-17. [PMID: 18620074 DOI: 10.1016/j.cbpa.2008.06.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Revised: 06/09/2008] [Accepted: 06/16/2008] [Indexed: 10/21/2022]
Abstract
REP8839 is a synthetic fluorovinylthiophene-containing diaryldiamine that inhibits bacterial methionyl tRNA synthetase (MetRS) and is a new chemical entity that represents a novel pharmacological class. The compound has potent in vitro antibacterial activity against many clinically important Gram-positive bacteria including the major skin pathogens Staphylococcus aureus and Streptococcus pyogenes. In light of the emergence of methicillin-resistant S. aureus in the community and increasing resistance to mupirocin, REP8839 is being evaluated as a topical agent for the treatment of superficial skin infections. REP8839 was active against resistant phenotypes of S. aureus and can be formulated at high concentrations to minimize the development of resistance. A formulation of REP8839 has demonstrated efficacy in a porcine partial thickness wound infection model against mupirocin-resistant S. aureus.
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Affiliation(s)
- Ian A Critchley
- Microbiology Research, Replidyne, Inc., 1450 Infinite Drive, Louisville, CO 80027, USA.
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33
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Ruggeri SG, Vanderplas BC, Anderson BG, Breitenbach R, Urban FJ, Stewart, III AM, Young GR. Regioselective Addition of Mesitol to a 2,4-Dichloropyridine. Org Process Res Dev 2008. [DOI: 10.1021/op800004q] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sally Gut Ruggeri
- Chemical Research and Development, Pfizer Global Research and Development, Pfizer Inc, Eastern Point Road, Groton, Connecticut 06340, U.S.A
| | - Brian C. Vanderplas
- Chemical Research and Development, Pfizer Global Research and Development, Pfizer Inc, Eastern Point Road, Groton, Connecticut 06340, U.S.A
| | - Bruce G. Anderson
- Chemical Research and Development, Pfizer Global Research and Development, Pfizer Inc, Eastern Point Road, Groton, Connecticut 06340, U.S.A
| | - Ralph Breitenbach
- Chemical Research and Development, Pfizer Global Research and Development, Pfizer Inc, Eastern Point Road, Groton, Connecticut 06340, U.S.A
| | - Frank J. Urban
- Chemical Research and Development, Pfizer Global Research and Development, Pfizer Inc, Eastern Point Road, Groton, Connecticut 06340, U.S.A
| | - A. Morgan Stewart, III
- Chemical Research and Development, Pfizer Global Research and Development, Pfizer Inc, Eastern Point Road, Groton, Connecticut 06340, U.S.A
| | - Gregory R. Young
- Chemical Research and Development, Pfizer Global Research and Development, Pfizer Inc, Eastern Point Road, Groton, Connecticut 06340, U.S.A
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Synthesis, IR-, NMR-, DFT and X-ray study of ferrocenyl heterocycles from thiosemicarbazones. Part 21: Study on ferrocenes. J Organomet Chem 2007. [DOI: 10.1016/j.jorganchem.2007.09.017] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Torchala M, Hoffmann M. IA, database of known ligands of aminoacyl-tRNA synthetases. J Comput Aided Mol Des 2007; 21:523-5. [PMID: 17882381 DOI: 10.1007/s10822-007-9135-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Accepted: 09/03/2007] [Indexed: 10/22/2022]
Abstract
The IA database contains 240 structures of known inhibitors of aminoacyl-tRNA synthetases. Structures can be downloaded in different file formats (mol, sdf, smile, png). The search engine offers possibility of searching for the ligands with a given functional group. Additionally, one can search for ligands that act on selected synthetases and from particular references. The data include information which synthetase a given ligand inhibits together with the inhibition constant (IC50) if known.
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Ochsner UA, Sun X, Jarvis T, Critchley I, Janjic N. Aminoacyl-tRNA synthetases: essential and still promising targets for new anti-infective agents. Expert Opin Investig Drugs 2007; 16:573-93. [PMID: 17461733 DOI: 10.1517/13543784.16.5.573] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The emergence of resistance to existing antibiotics demands the development of novel antimicrobial agents directed against novel targets. Historically, bacterial cell wall synthesis, protein, and DNA and RNA synthesis have been major targets of very successful classes of antibiotics such as beta-lactams, glycopeptides, macrolides, aminoglycosides, tetracyclines, rifampicins and quinolones. Recently, efforts have been made to develop novel agents against validated targets in these pathways but also against new, previously unexploited targets. The era of genomics has provided insights into novel targets in microbial pathogens. Among the less exploited--but still promising--targets is the family of 20 aminoacyl-tRNA synthetases (aaRSs), which are essential for protein synthesis. These targets have been validated in nature as aaRS inhibition has been shown as the specific mode of action for many natural antimicrobial agents synthesized by bacteria and fungi. Therefore, aaRSs have the potential to be targeted by novel agents either from synthetic or natural sources to yield specific and selective anti-infectives. Numerous high-throughput screening programs aimed at identifying aaRS inhibitors have been performed over the last 20 years. A large number of promising lead compounds have been identified but only a few agents have moved forward into clinical development. This review provides an update on the present strategies to develop novel aaRS inhibitors as anti-infective drugs.
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Affiliation(s)
- Urs A Ochsner
- Replidyne, Inc., 1450 Infinite Dr, Louisville, CO 80027, USA.
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Kedar GC, Brown-Driver V, Reyes DR, Hilgers MT, Stidham MA, Shaw KJ, Finn J, Haselbeck RJ. Evaluation of the metS and murB loci for antibiotic discovery using targeted antisense RNA expression analysis in Bacillus anthracis. Antimicrob Agents Chemother 2007; 51:1708-18. [PMID: 17339372 PMCID: PMC1855544 DOI: 10.1128/aac.01180-06] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The biowarfare-relevant bacterial pathogen Bacillus anthracis contains two paralogs each of the metS and murB genes, which encode the important antibiotic target functions methionyl-tRNA synthetase and UDP-N-acetylenolpyruvoylglucosamine reductase, respectively. Empirical screens were conducted to detect and characterize gene fragments of each of these four genes that could cause growth reduction of B. anthracis when inducibly expressed from a plasmid-borne promoter. Numerous such gene fragments that were overwhelmingly in the antisense orientation were identified for the metS1 and murB2 alleles, while no such orientation bias was seen for the metS2 and murB1 alleles. Gene replacement mutagenesis was used to confirm the essentiality of the metS1 and murB2 alleles, and the nonessentiality of the metS2 and murB1 alleles, for vegetative growth. Induced transcription of RNA from metS1 and murB2 antisense-oriented gene fragments resulted in specific reduction of mRNA of their cognate genes. Attenuation of MetS1 enzyme expression hypersensitized B. anthracis cells to a MetS-specific antimicrobial compound but not to other antibiotics that affect cell wall assembly, fatty acid biosynthesis, protein translation, or DNA replication. Antisense-dependent reduction of MurB2 enzyme expression caused hypersensitivity to beta-lactam antibiotics, a synergistic response that has also been noted for the MurA-specific antibiotic fosfomycin. These experiments form the basis of mode-of-action detection assays that can be used in the discovery of novel MetS- or MurB-specific antibiotic drugs that are effective against B. anthracis or other gram-positive bacterial pathogens.
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Affiliation(s)
- G C Kedar
- Trius Therapeutics Inc, San Diego, CA 92121, USA
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Bharatham N, Bharatham K, Lee KW. Pharmacophore identification and virtual screening for methionyl-tRNA synthetase inhibitors. J Mol Graph Model 2007; 25:813-23. [PMID: 16996282 DOI: 10.1016/j.jmgm.2006.08.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2006] [Revised: 08/03/2006] [Accepted: 08/03/2006] [Indexed: 11/16/2022]
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are essential enzymes involved in protein biosynthesis in all living organisms and are an unexploited antibacterial targets, as many strains of bacteria have become resistant to all established classes of antibiotics. Therefore, the main aim of this study is to discover new lead molecules which would be useful as anti-bacterial compounds. Pharmacophore models were developed by using CATALYST HypoGen with a training set of 29 diverse methionyl-tRNA synthetase (MetRS) inhibitors. The best quantitative pharmacophore hypothesis (Hypo1) obtained a correlation coefficient of 0.975, root mean square deviation (RMSD) of 0.55 and cost difference (null cost-total cost) of 70.32. This Hypo1 was validated by two methods, first by using 104 test set molecules which resulted a correlation of 0.926 between HypoGen estimated activities versus experimental activities and secondly by Cat-Scramble validation method. This validated pharmacophore model was further used for screening databases for discovery of new MetRS inhibitors. The new lead compounds were further analyzed for drug-like properties. Homology modeled structure of Staphylococcus aureus MetRS was built and molecular docking studies were performed with many inhibitors using the newly built protein structure. Finally, it was found that the new leads exhibited good estimated inhibitory activity, calculated binding properties similar to experimentally proven compounds and also favorable drug-like properties.
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Affiliation(s)
- Nagakumar Bharatham
- Department of Biochemistry, Division of Applied Life Science, Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701, Republic of Korea
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Janin YL. Antituberculosis drugs: ten years of research. Bioorg Med Chem 2007; 15:2479-513. [PMID: 17291770 DOI: 10.1016/j.bmc.2007.01.030] [Citation(s) in RCA: 335] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Revised: 12/26/2006] [Accepted: 01/17/2007] [Indexed: 02/03/2023]
Abstract
Tuberculosis is today amongst the worldwide health threats. As resistant strains of Mycobacterium tuberculosis have slowly emerged, treatment failure is too often a fact, especially in countries lacking the necessary health care organisation to provide the long and costly treatment adapted to patients. Because of lack of treatment or lack of adapted treatment, at least two million people will die of tuberculosis this year. Due to this concern, this infectious disease was the focus of renewed scientific interest in the last decade. Regimens were optimized and much was learnt on the mechanisms of action of the antituberculosis drugs used. Moreover, the quest for original drugs overcoming some of the problems of current regimens also became the focus of research programmes and many new series of M. tuberculosis growth inhibitors were reported. This review presents the drugs currently used in antituberculosis treatments and the most advanced compounds undergoing clinical trials. We then provide a description of their mechanism of action along with other series of inhibitors known to act on related biochemical targets. This is followed by other inhibitors of M. tuberculosis growth, including recently reported compounds devoid of a reported mechanism of action.
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Affiliation(s)
- Yves L Janin
- URA 2128 CNRS-Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France.
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Bryskier A. Anti-MRSA agents: under investigation, in the exploratory phase and clinically available. Expert Rev Anti Infect Ther 2007; 3:505-53. [PMID: 16107196 DOI: 10.1586/14787210.3.4.505] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Staphylococcal infections are difficult to treat due to the rapid emergence of methicillin-resistant staphylococci and, unfortunately, vancomycin-intermediate or -resistant staphylococci. Numerous alternative treatments are urgently required. In this special report, intensive research of new molecules is highlighted--in known antibacterial families and new medicinal chemical entities.
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Affiliation(s)
- André Bryskier
- Aventis Pharma, Infectious Disease Group-Clinical Pharmacology, 102, Route de Noisy, 93230 Romaiville, Cedex, France.
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Kim SY, Yoon EJ, Choi EC, Kim S, Kang T, Samrin F, Puri S, Lee J. Design and synthesis of quinolinones as methionyl-tRNA synthetase inhibitors. Bioorg Med Chem 2006; 14:7154-9. [PMID: 16854585 DOI: 10.1016/j.bmc.2006.06.062] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Revised: 06/26/2006] [Accepted: 06/28/2006] [Indexed: 10/24/2022]
Abstract
Five new structural analogues of substituted-1H-quinolinones (19, 20, 23, 24, and 26) have been synthesized and evaluated for Staphylococcus aureus methionyl-tRNA synthetase enzyme inhibitory activity. These compounds were also tested against pathogens of six S. aureus, two Enterococcus faecalis, and one Enterococcus faecium. Among all the synthesized quinolinones, compound 20 displayed significant inhibitory activities in the strains of E. faecalis and E. faecium.
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Ochsner UA, Young CL, Stone KC, Dean FB, Janjic N, Critchley IA. Mode of action and biochemical characterization of REP8839, a novel inhibitor of methionyl-tRNA synthetase. Antimicrob Agents Chemother 2006; 49:4253-62. [PMID: 16189106 PMCID: PMC1251548 DOI: 10.1128/aac.49.10.4253-4262.2005] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aminoacyl-tRNA synthetases have attracted interest as essential and novel targets involved in bacterial protein synthesis. REP8839 is a potent inhibitor of MetS, the methionyl-tRNA synthetase in Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), and in Streptococcus pyogenes. The biochemical activity of REP8839 was shown by specific inhibition of purified S. aureus MetS (50% inhibitory concentration, <1.9 nM). Target specificity was confirmed by overexpression of the metS gene in S. aureus, resulting in an eightfold increase in the MIC for REP8839. Macromolecular synthesis assays in the presence of REP8839 demonstrated a dose-dependent inhibition of protein synthesis and RNA synthesis in S. pneumoniae R6, but only protein synthesis was affected in an isogenic rel mutant deficient in the stringent response. Strains with reduced susceptibility to REP8839 were generated by selection of strains with spontaneous mutations and through serial passages. Point mutations within the metS gene were mapped, leading to a total of 23 different amino acid substitutions within MetS that were located around the modeled active site. The most frequent MetS mutations were I57N, leading to a shift in the MIC from 0.06 microg/ml to 4 microg/ml, and G54S, resulting in a MIC of 32 microg/ml that was associated with a reduced growth rate. The mutation prevention concentration was 32 microg/ml in four S. aureus strains (methicillin-sensitive S. aureus and MRSA), which is well below the drug concentration of 2% (20,000 microg/ml) in a topical formulation. In conclusion, we demonstrate by biochemical, physiologic, and genetic mode-of-action studies that REP8839 exerts its antibacterial activity through specific inhibition of MetS, a novel target.
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Critchley IA, Young CL, Stone KC, Ochsner UA, Guiles J, Tarasow T, Janjic N. Antibacterial activity of REP8839, a new antibiotic for topical use. Antimicrob Agents Chemother 2005; 49:4247-52. [PMID: 16189105 PMCID: PMC1251549 DOI: 10.1128/aac.49.10.4247-4252.2005] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2005] [Revised: 06/14/2005] [Accepted: 07/07/2005] [Indexed: 11/20/2022] Open
Abstract
REP8839 is a novel methionyl-tRNA synthetase (MetS) inhibitor with potent antibacterial activity against clinical isolates of Staphylococcus aureus, Streptococcus pyogenes, and other clinically important gram-positive bacteria but little activity against gram-negative bacteria. All isolates of S. aureus, including strains resistant to methicillin, mupirocin, vancomycin, and linezolid were susceptible to REP8839 at concentrations of < or =0.5 microg/ml. REP8839 was also active against Staphylococcus epidermidis, including multiply resistant strains (MIC, < or =0.25 microg/ml). All S. pyogenes isolates were susceptible to REP8839 at concentrations of < or =0.25 microg/ml, suggesting that MetS2, a second enzyme previously identified in Streptococcus pneumoniae, was not present in this organism. REP8839 was highly bound to the protein of human serum, and activity was not greatly influenced by inoculum size but was affected by pH, exhibiting optimal antibacterial activity in a neutral medium rather than a weak acidic medium. Like mupirocin, REP8839 exhibited bacteriostatic activity against key pathogens. The emergence of mupirocin resistance in S. aureus highlights the need for a new topical antibiotic with the ability to inhibit high-level mupirocin-resistant strains and other emerging phenotypes, such as vancomycin-resistant and community-acquired methicillin-resistant isolates.
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