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Pang L, Weeks SD, Van Aerschot A. Aminoacyl-tRNA Synthetases as Valuable Targets for Antimicrobial Drug Discovery. Int J Mol Sci 2021; 22:1750. [PMID: 33578647 PMCID: PMC7916415 DOI: 10.3390/ijms22041750] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/04/2021] [Accepted: 02/06/2021] [Indexed: 12/20/2022] Open
Abstract
Aminoacyl-tRNA synthetases (aaRSs) catalyze the esterification of tRNA with a cognate amino acid and are essential enzymes in all three kingdoms of life. Due to their important role in the translation of the genetic code, aaRSs have been recognized as suitable targets for the development of small molecule anti-infectives. In this review, following a concise discussion of aaRS catalytic and proof-reading activities, the various inhibitory mechanisms of reported natural and synthetic aaRS inhibitors are discussed. Using the expanding repository of ligand-bound X-ray crystal structures, we classified these compounds based on their binding sites, focusing on their ability to compete with the association of one, or more of the canonical aaRS substrates. In parallel, we examined the determinants of species-selectivity and discuss potential resistance mechanisms of some of the inhibitor classes. Combined, this structural perspective highlights the opportunities for further exploration of the aaRS enzyme family as antimicrobial targets.
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Affiliation(s)
- Luping Pang
- KU Leuven, Rega Institute for Medical Research, Medicinal Chemistry, Herestraat 49–box 1041, 3000 Leuven, Belgium;
- KU Leuven, Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, Herestraat 49–box 822, 3000 Leuven, Belgium
| | | | - Arthur Van Aerschot
- KU Leuven, Rega Institute for Medical Research, Medicinal Chemistry, Herestraat 49–box 1041, 3000 Leuven, Belgium;
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Synthesis and Biological Evaluation of Lipophilic Nucleoside Analogues as Inhibitors of Aminoacyl-tRNA Synthetases. Antibiotics (Basel) 2019; 8:antibiotics8040180. [PMID: 31600972 PMCID: PMC6963541 DOI: 10.3390/antibiotics8040180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 10/02/2019] [Accepted: 10/04/2019] [Indexed: 11/16/2022] Open
Abstract
Emerging antibiotic resistance in pathogenic bacteria and reduction of compounds in the existing antibiotics discovery pipeline is the most critical concern for healthcare professionals. A potential solution aims to explore new or existing targets/compounds. Inhibition of bacterial aminoacyl-tRNA synthetase (aaRSs) could be one such target for the development of antibiotics. The aaRSs are a group of enzymes that catalyze the transfer of an amino acid to their cognate tRNA and therefore play a pivotal role in translation. Thus, selective inhibition of these enzymes could be detrimental to microbes. The 5′-O-(N-(L-aminoacyl)) sulfamoyladenosines (aaSAs) are potent inhibitors of the respective aaRSs, however due to their polarity and charged nature they cannot cross the bacterial membranes. In this work, we increased the lipophilicity of these existing aaSAs in an effort to promote their penetration through the bacterial membrane. Two strategies were followed, either attaching a (permanent) alkyl moiety at the adenine ring via alkylation of the N6-position or introducing a lipophilic biodegradable prodrug moiety at the alpha-terminal amine, totaling eight new aaSA analogues. All synthesized compounds were evaluated in vitro using either a purified Escherichiacoli aaRS enzyme or in presence of total cellular extract obtained from E. coli. The prodrugs showed comparable inhibitory activity to the parent aaSA analogues, indicating metabolic activation in cellular extracts, but had little effect on bacteria. During evaluation of the N6-alkylated compounds against different microbes, the N6-octyl containing congener 6b showed minimum inhibitory concentration (MIC) of 12.5 µM against Sarcina lutea while the dodecyl analogue 6c displayed MIC of 6.25 µM against Candidaalbicans.
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Francklyn CS, Mullen P. Progress and challenges in aminoacyl-tRNA synthetase-based therapeutics. J Biol Chem 2019; 294:5365-5385. [PMID: 30670594 DOI: 10.1074/jbc.rev118.002956] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Aminoacyl-tRNA synthetases (ARSs) are universal enzymes that catalyze the attachment of amino acids to the 3' ends of their cognate tRNAs. The resulting aminoacylated tRNAs are escorted to the ribosome where they enter protein synthesis. By specifically matching amino acids to defined anticodon sequences in tRNAs, ARSs are essential to the physical interpretation of the genetic code. In addition to their canonical role in protein synthesis, ARSs are also involved in RNA splicing, transcriptional regulation, translation, and other aspects of cellular homeostasis. Likewise, aminoacylated tRNAs serve as amino acid donors for biosynthetic processes distinct from protein synthesis, including lipid modification and antibiotic biosynthesis. Thanks to the wealth of details on ARS structures and functions and the growing appreciation of their additional roles regulating cellular homeostasis, opportunities for the development of clinically useful ARS inhibitors are emerging to manage microbial and parasite infections. Exploitation of these opportunities has been stimulated by the discovery of new inhibitor frameworks, the use of semi-synthetic approaches combining chemistry and genome engineering, and more powerful techniques for identifying leads from the screening of large chemical libraries. Here, we review the inhibition of ARSs by small molecules, including the various families of natural products, as well as inhibitors developed by either rational design or high-throughput screening as antibiotics and anti-parasitic therapeutics.
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Affiliation(s)
- Christopher S Francklyn
- From the Department of Biochemistry, College of Medicine, University of Vermont, Burlington, Vermont 05405
| | - Patrick Mullen
- From the Department of Biochemistry, College of Medicine, University of Vermont, Burlington, Vermont 05405
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Kong J, Fang P, Madoux F, Spicer TP, Scampavia L, Kim S, Guo M. High-Throughput Screening for Protein Synthesis Inhibitors Targeting Aminoacyl-tRNA Synthetases. SLAS DISCOVERY 2017; 23:174-182. [PMID: 29020503 DOI: 10.1177/2472555217734128] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Aminoacylation has been implicated in a wide variety of cancers. Aminoacyl-tRNA synthetases (ARSs) exist in large excess in tumor cells due to their increased demand for translation, whereas most other protein-synthesis apparatuses are quantitatively limited. Among other components that constitute the translation machinery-namely, tRNA, amino acid, ATP, and ARS-ARS is the only target that can be blocked by small molecules. No constitutively active ARSs have been reported, and mutations of ARS can cause inaccurate substrate recognition and malformation of the multi-ARS complex (MSC). Hence, interference of the activity is expected to be independent of genotype without developing resistance. Here, we report a high-throughput screening (HTS) system to find mammalian ARS inhibitors. The rabbit-reticulocyte lysate we used closely resembles both the individual and complexed structures of human ARSs, and it may predispose active compounds that are readily applicable for humankind. This assay was further validated because it identified familiar translational inhibitors from a pilot screen, such as emetine, proving its suitability for our purpose. The assay demonstrated excellent quality control (QC) parameters and reproducibility, and is proven ready for further HTS campaigns with large chemical libraries.
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Affiliation(s)
- Jiwon Kong
- 1 Medicinal Bioconvergence Research Center, College of Pharmacy, Seoul National University, Seoul, Korea
| | - Pengfei Fang
- 2 Department of Cancer Biology, Scripps Research Institute, Scripps Florida, Jupiter, FL, USA.,3 State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
| | - Franck Madoux
- 4 Department of Molecular Medicine, Scripps Research Institute, Scripps Florida, Jupiter, FL, USA.,5 Discovery Technologies, Amgen, Thousand Oaks, CA, USA
| | - Timothy P Spicer
- 4 Department of Molecular Medicine, Scripps Research Institute, Scripps Florida, Jupiter, FL, USA
| | - Louis Scampavia
- 4 Department of Molecular Medicine, Scripps Research Institute, Scripps Florida, Jupiter, FL, USA
| | - Sunghoon Kim
- 1 Medicinal Bioconvergence Research Center, College of Pharmacy, Seoul National University, Seoul, Korea.,6 Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Korea
| | - Min Guo
- 2 Department of Cancer Biology, Scripps Research Institute, Scripps Florida, Jupiter, FL, USA
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Serpi M, Ferrari V, Pertusati F. Nucleoside Derived Antibiotics to Fight Microbial Drug Resistance: New Utilities for an Established Class of Drugs? J Med Chem 2016; 59:10343-10382. [PMID: 27607900 DOI: 10.1021/acs.jmedchem.6b00325] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Novel antibiotics are urgently needed to combat the rise of infections due to drug-resistant microorganisms. Numerous natural nucleosides and their synthetically modified analogues have been reported to have moderate to good antibiotic activity against different bacterial and fungal strains. Nucleoside-based compounds target several crucial processes of bacterial and fungal cells such as nucleoside metabolism and cell wall, nucleic acid, and protein biosynthesis. Nucleoside analogues have also been shown to target many other bacterial and fungal cellular processes although these are not well characterized and may therefore represent opportunities to discover new drugs with unique mechanisms of action. In this Perspective, we demonstrate that nucleoside analogues, cornerstones of anticancer and antiviral treatments, also have great potential to be repurposed as antibiotics so that an old drug can learn new tricks.
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Affiliation(s)
- Michaela Serpi
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University , Redwood Building, King Edward VII Avenue, CF10 3NB Cardiff, United Kingdom
| | - Valentina Ferrari
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University , Redwood Building, King Edward VII Avenue, CF10 3NB Cardiff, United Kingdom
| | - Fabrizio Pertusati
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University , Redwood Building, King Edward VII Avenue, CF10 3NB Cardiff, United Kingdom
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Abstract
Aminoacyl-tRNA synthetases (aaRSs) are modular enzymes globally conserved in the three kingdoms of life. All catalyze the same two-step reaction, i.e., the attachment of a proteinogenic amino acid on their cognate tRNAs, thereby mediating the correct expression of the genetic code. In addition, some aaRSs acquired other functions beyond this key role in translation. Genomics and X-ray crystallography have revealed great structural diversity in aaRSs (e.g., in oligomery and modularity, in ranking into two distinct groups each subdivided in 3 subgroups, by additional domains appended on the catalytic modules). AaRSs show huge structural plasticity related to function and limited idiosyncrasies that are kingdom or even species specific (e.g., the presence in many Bacteria of non discriminating aaRSs compensating for the absence of one or two specific aaRSs, notably AsnRS and/or GlnRS). Diversity, as well, occurs in the mechanisms of aaRS gene regulation that are not conserved in evolution, notably between distant groups such as Gram-positive and Gram-negative Bacteria. The review focuses on bacterial aaRSs (and their paralogs) and covers their structure, function, regulation, and evolution. Structure/function relationships are emphasized, notably the enzymology of tRNA aminoacylation and the editing mechanisms for correction of activation and charging errors. The huge amount of genomic and structural data that accumulated in last two decades is reviewed, showing how the field moved from essentially reductionist biology towards more global and integrated approaches. Likewise, the alternative functions of aaRSs and those of aaRS paralogs (e.g., during cell wall biogenesis and other metabolic processes in or outside protein synthesis) are reviewed. Since aaRS phylogenies present promiscuous bacterial, archaeal, and eukaryal features, similarities and differences in the properties of aaRSs from the three kingdoms of life are pinpointed throughout the review and distinctive characteristics of bacterium-like synthetases from organelles are outlined.
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Affiliation(s)
- Richard Giegé
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 67084 Strasbourg, France
| | - Mathias Springer
- Université Paris Diderot, Sorbonne Cité, UPR9073 CNRS, IBPC, 75005 Paris, France
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Gadakh B, Smaers S, Rozenski J, Froeyen M, Van Aerschot A. 5'-(N-aminoacyl)-sulfonamido-5'-deoxyadenosine: attempts for a stable alternative for aminoacyl-sulfamoyl adenosines as aaRS inhibitors. Eur J Med Chem 2015; 93:227-36. [PMID: 25686591 DOI: 10.1016/j.ejmech.2015.02.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 02/04/2015] [Accepted: 02/07/2015] [Indexed: 10/24/2022]
Abstract
Synthesis of aminoacyl-sulfamoyl adenosines (aaSAs) and their peptidyl conjugates as aminoacyl tRNA synthetase (aaRS) inhibitors remains problematic due to the low yield of the aminoacylation and the subsequent conjugation reaction causing concomitant formation of a cyclic adenosine derivative. In an effort to reduce this undesirable side reaction, we aimed to prepare the corresponding aminoacyl sulfonamide (aaSoA) analogues as more stable alternatives for aaSA derivatives. Deletion of the 5'-oxygen in aaSA analogues should render the C-5' less electrophilic and therefore improve the stability of the aminoacyl sulfamate analogues. We therefore synthesized six sulfonamides and compared their activity against the respective aaSA analogues. However, except for the aspartyl derivative, the new compounds are not able to inhibit the corresponding aaRS. Possible reasons for this loss of activity are discussed by modeling and comparison of the newly synthesized aaSoA derivatives with their parent aaSA analogues.
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Affiliation(s)
- Bharat Gadakh
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, 3000 Leuven, Belgium
| | - Simon Smaers
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, 3000 Leuven, Belgium
| | - Jef Rozenski
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, 3000 Leuven, Belgium
| | - Mathy Froeyen
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, 3000 Leuven, Belgium
| | - Arthur Van Aerschot
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, 3000 Leuven, Belgium.
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Gurcha SS, Usha V, Cox JAG, Fütterer K, Abrahams KA, Bhatt A, Alderwick LJ, Reynolds RC, Loman NJ, Nataraj V, Alemparte C, Barros D, Lloyd AJ, Ballell L, Hobrath JV, Besra GS. Biochemical and structural characterization of mycobacterial aspartyl-tRNA synthetase AspS, a promising TB drug target. PLoS One 2014; 9:e113568. [PMID: 25409504 PMCID: PMC4237437 DOI: 10.1371/journal.pone.0113568] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 10/13/2014] [Indexed: 11/19/2022] Open
Abstract
The human pathogen Mycobacterium tuberculosis is the causative agent of pulmonary tuberculosis (TB), a disease with high worldwide mortality rates. Current treatment programs are under significant threat from multi-drug and extensively-drug resistant strains of M. tuberculosis, and it is essential to identify new inhibitors and their targets. We generated spontaneous resistant mutants in Mycobacterium bovis BCG in the presence of 10× the minimum inhibitory concentration (MIC) of compound 1, a previously identified potent inhibitor of mycobacterial growth in culture. Whole genome sequencing of two resistant mutants revealed in one case a single nucleotide polymorphism in the gene aspS at 535GAC>535AAC (D179N), while in the second mutant a single nucleotide polymorphism was identified upstream of the aspS promoter region. We probed whole cell target engagement by overexpressing either M. bovis BCG aspS or Mycobacterium smegmatis aspS, which resulted in a ten-fold and greater than ten-fold increase, respectively, of the MIC against compound 1. To analyse the impact of inhibitor 1 on M. tuberculosis AspS (Mt-AspS) activity we over-expressed, purified and characterised the kinetics of this enzyme using a robust tRNA-independent assay adapted to a high-throughput screening format. Finally, to aid hit-to-lead optimization, the crystal structure of apo M. smegmatis AspS was determined to a resolution of 2.4 Å.
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Affiliation(s)
- Sudagar S. Gurcha
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Veeraraghavan Usha
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Jonathan A. G. Cox
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Klaus Fütterer
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Katherine A. Abrahams
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Apoorva Bhatt
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Luke J. Alderwick
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Robert C. Reynolds
- Department of Chemistry, University of Alabama at Birmingham, College of Arts and Sciences, 1530 3rd Avenue South, Birmingham, Alabama, 35294-1240, United States of America
| | - Nicholas J. Loman
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - VijayaShankar Nataraj
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Carlos Alemparte
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - David Barros
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - Adrian J. Lloyd
- Department of Life Sciences, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Lluis Ballell
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - Judith V. Hobrath
- Organic Chemistry Department, Southern Research Institute, Birmingham, Alabama, 35205, United States of America
| | - Gurdyal S. Besra
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
- * E-mail:
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