1
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Parmar S, Bume DD, Conelly C, Boer R, Prestwood PR, Wang Z, Labuhn H, Sinnadurai K, Feri A, Ouellet J, Homan P, Numata T, Schneekloth JS. Mechanistic Analysis of Riboswitch Ligand Interactions Provides Insights into Pharmacological Control over Gene Expression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.23.581746. [PMID: 38903087 PMCID: PMC11188086 DOI: 10.1101/2024.02.23.581746] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
Riboswitches are structured RNA elements that regulate gene expression upon binding to small molecule ligands. Understanding the mechanisms by which small molecules impact riboswitch activity is key to developing potent, selective ligands for these and other RNA targets. We report the structure-informed design of chemically diverse synthetic ligands for PreQ 1 riboswitches. Multiple X-ray co-crystal structures of synthetic ligands with the Thermoanaerobacter tengcongensis ( Tte )-PreQ 1 riboswitch confirm a common binding site with the cognate ligand, despite considerable chemical differences among the ligands. Structure probing assays demonstrate that one ligand causes conformational changes similar to PreQ 1 in six structurally and mechanistically diverse PreQ 1 riboswitch aptamers. Single-molecule force spectroscopy is used to demonstrate differential modes of riboswitch stabilization by the ligands. Binding of the natural ligand brings about the formation of a persistent, folded pseudoknot structure, whereas a synthetic ligand decreases the rate of unfolding through a kinetic mechanism. Single round transcription termination assays show the biochemical activity of the ligands, while a GFP reporter system reveals compound activity in regulating gene expression in live cells without toxicity. Taken together, this study reveals that diverse small molecules can impact gene expression in live cells by altering conformational changes in RNA structures through distinct mechanisms.
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2
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Lou Y, Woodson SA. Co-transcriptional folding of the glmS ribozyme enables a rapid response to metabolite. Nucleic Acids Res 2024; 52:872-884. [PMID: 38000388 PMCID: PMC10810187 DOI: 10.1093/nar/gkad1120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 10/24/2023] [Accepted: 11/07/2023] [Indexed: 11/26/2023] Open
Abstract
The glmS ribozyme riboswitch, located in the 5' untranslated region of the Bacillus subtilis glmS messenger RNA (mRNA), regulates cell wall biosynthesis through ligand-induced self-cleavage and decay of the glmS mRNA. Although self-cleavage of the refolded glmS ribozyme has been studied extensively, it is not known how early the ribozyme folds and self-cleaves during transcription. Here, we combine single-molecule fluorescence with kinetic modeling to show that self-cleavage can occur during transcription before the ribozyme is fully synthesized. Moreover, co-transcriptional folding of the RNA at a physiological elongation rate allows the ribozyme catalytic core to react without the downstream peripheral stability domain. Dimethyl sulfate footprinting further revealed how slow sequential folding favors formation of the native core structure through fraying of misfolded helices and nucleation of a native pseudoknot. Ribozyme self-cleavage at an early stage of transcription may benefit glmS regulation in B. subtilis, as it exposes the mRNA to exoribonuclease before translation of the open reading frame can begin. Our results emphasize the importance of co-transcriptional folding of RNA tertiary structure for cis-regulation of mRNA stability.
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Affiliation(s)
- Yuan Lou
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
| | - Sarah A Woodson
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
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3
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Pavlova N, Traykovska M, Penchovsky R. Targeting FMN, TPP, SAM-I, and glmS Riboswitches with Chimeric Antisense Oligonucleotides for Completely Rational Antibacterial Drug Development. Antibiotics (Basel) 2023; 12:1607. [PMID: 37998809 PMCID: PMC10668854 DOI: 10.3390/antibiotics12111607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/05/2023] [Accepted: 11/07/2023] [Indexed: 11/25/2023] Open
Abstract
Antimicrobial drug resistance has emerged as a significant challenge in contemporary medicine due to the proliferation of numerous bacterial strains resistant to all existing antibiotics. Meanwhile, riboswitches have emerged as promising targets for discovering antibacterial drugs. Riboswitches are regulatory elements in certain bacterial mRNAs that can bind to specific molecules and control gene expression via transcriptional termination, prevention of translation, or mRNA destabilization. By targeting riboswitches, we aim to develop innovative strategies to combat antibiotic-resistant bacteria and enhance the efficacy of antibacterial treatments. This convergence of challenges and opportunities underscores the ongoing quest to revolutionize medical approaches against evolving bacterial threats. For the first time, this innovative review describes the rational design and applications of chimeric antisense oligonucleotides as antibacterial agents targeting four riboswitches selected based on genome-wide bioinformatic analyses. The antisense oligonucleotides are coupled with the cell-penetrating oligopeptide pVEC, which penetrates Gram-positive and Gram-negative bacteria and specifically targets glmS, FMN, TPP, and SAM-I riboswitches in Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli. The average antibiotic dosage of antisense oligonucleotides that inhibits 80% of bacterial growth is around 700 nM (4.5 μg/mL). Antisense oligonucleotides do not exhibit toxicity in human cell lines at this concentration. The results demonstrate that these riboswitches are suitable targets for antibacterial drug development using antisense oligonucleotide technology. The approach is fully rational because selecting suitable riboswitch targets and designing ASOs that target them are based on predefined criteria. The approach can be used to develop narrow or broad-spectrum antibiotics against multidrug-resistant bacterial strains for a short time. The approach is easily adaptive to new resistance using targeting NGS technology.
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Affiliation(s)
| | | | - Robert Penchovsky
- Laboratory of Synthetic Biology and Bioinformatics, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 8 Dragan Tzankov Blvd., 1164 Sofia, Bulgaria
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4
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Silkenath B, Kläge D, Altwein H, Schmidhäuser N, Mayer G, Hartig JS, Wittmann V. Phosphonate and Thiasugar Analogues of Glucosamine-6-phosphate: Activation of the glmS Riboswitch and Antibiotic Activity. ACS Chem Biol 2023; 18:2324-2334. [PMID: 37793187 PMCID: PMC10594590 DOI: 10.1021/acschembio.3c00452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 09/19/2023] [Indexed: 10/06/2023]
Abstract
The glmS riboswitch is a motif found in 5'-untranslated regions of bacterial mRNA that controls the synthesis of glucosamine-6-phosphate (GlcN6P), an essential building block for the bacterial cell wall, by a feedback mechanism. Activation of the glmS riboswitch by GlcN6P mimics interferes with the ability of bacteria to synthesize its cell wall. Accordingly, GlcN6P mimics acting as glmS activators are promising candidates for future antibiotic drugs that may overcome emerging bacterial resistance against established antibiotics. We describe the synthesis of a series of phosphonate mimics of GlcN6P as well as the thiasugar analogue of GlcN6P. The phosphonate mimics differ in their pKa value to answer the question of whether derivatives with a pKa matching that of GlcN6P would be efficient glmS activators. We found that all derivatives activate the riboswitch, however, less efficiently than GlcN6P. This observation can be explained by the missing hydrogen bonds in the case of phosphonates and is valuable information for the design of future GlcN6P mimics. The thiasugar analogue of GlcN6P on the other hand turned out to be a glmS riboswitch activator with the same activity as the natural metabolite GlcN6P. The nonphosphorylated thiasugar displayed antimicrobial activity against certain bacilli. Therefore, the compound is a promising lead structure for the development of future antibiotics with a potentially novel mode of action.
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Affiliation(s)
- Bjarne Silkenath
- Department
of Chemistry, University of Konstanz, 78457 Konstanz, Germany
| | - Dennis Kläge
- Department
of Chemistry, University of Konstanz, 78457 Konstanz, Germany
| | - Hanna Altwein
- Department
of Chemistry, University of Konstanz, 78457 Konstanz, Germany
| | - Nina Schmidhäuser
- Department
of Chemistry, University of Konstanz, 78457 Konstanz, Germany
| | - Günter Mayer
- LIMES
Institute, Center for Aptamer Research & Development, University of Bonn, 53121 Bonn, Germany
| | - Jörg S. Hartig
- Department
of Chemistry, University of Konstanz, 78457 Konstanz, Germany
| | - Valentin Wittmann
- Department
of Chemistry, University of Konstanz, 78457 Konstanz, Germany
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5
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Stängle D, Silkenath B, Gehle P, Esser A, Mayer G, Wittmann V. Carba-Sugar Analogs of Glucosamine-6-Phosphate: New Activators for the glmS Riboswitch. Chemistry 2023; 29:e202202378. [PMID: 36326082 PMCID: PMC10099210 DOI: 10.1002/chem.202202378] [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: 07/30/2022] [Indexed: 11/06/2022]
Abstract
Riboswitches are 5'-untranslated mRNA regions mostly found in bacteria. They are promising drug targets to overcome emerging bacterial resistance against commonly used antibiotics. The glmS riboswitch is unique among the family of riboswitches as it is a ribozyme that undergoes self-cleavage upon binding to glucosamine-6-phosphate (GlcN6P). Previously, we showed that carba glucosamine-6-phosphate (carba-GlcN6P) induces self-cleavage of the riboswitch with a potency similar to that of GlcN6P. Here, we report a synthetic approach to a new class of carba-GlcN6P derivatives with an alkoxy substituent in the carba position. Key features of the synthesis are a ring closing metathesis followed by a hydroboration. The strategy gives access to libraries of carba-GlcN6P derivatives. Ribozyme cleavage assays unraveled new activators for the glmS riboswitch from Listeria monocytogenes and Clostridium difficile.
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Affiliation(s)
- David Stängle
- Department of Chemistry, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany
| | - Bjarne Silkenath
- Department of Chemistry, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany
| | - Paul Gehle
- LIMES Institute, Center for Aptamer Research & Development, University of Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Anna Esser
- LIMES Institute, Center for Aptamer Research & Development, University of Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Günter Mayer
- LIMES Institute, Center for Aptamer Research & Development, University of Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Valentin Wittmann
- Department of Chemistry, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany
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6
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Esser A, Mayer G. Characterization of the glmS Ribozymes from Listeria Monocytogenes and Clostridium Difficile. Chemistry 2023; 29:e202202376. [PMID: 36194523 PMCID: PMC10099748 DOI: 10.1002/chem.202202376] [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: 07/30/2022] [Indexed: 11/23/2022]
Abstract
The glmS ribozyme regulates the expression of the essential GlmS enzyme being involved in cell wall biosynthesis. While >450 variants of the glmS ribozyme were identified by in silico approaches and homology searches, only a few have yet been experimentally investigated. Herein, we validate and characterize the glmS ribozymes of the human pathogens Clostridium difficile and Listeria monocytogenes. Both ribozymes, as their previous characterized homologs rely on glucosamine-6-phosphate as co-factor and the presence of divalent cations for exerting the cleavage reaction. The observed EC50 values in turn were found to be in the submicromolar range, at least an order of magnitude lower than observed for glmS ribozymes from other bacteria. The glmS ribozyme of L. monocytogenes was further shown to bear unique properties. It discriminates between co-factors very stringently and other than the glmS ribozyme of C. difficile retains activity at low temperatures. This finding illustrates that albeit being highly conserved, glmS ribozymes have unique characteristics.
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Affiliation(s)
- Anna Esser
- Life & Medical Sciences Institute, University of Bonn, Gerhard-Domagk-Str. 1, 53121, Bonn, Germany
| | - Günter Mayer
- Life & Medical Sciences Institute, University of Bonn, Gerhard-Domagk-Str. 1, 53121, Bonn, Germany.,Center of Aptamer Research & Development, University of Bonn, Gerhard-Domagk-Str. 1, 53121, Bonn, Germany
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7
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Di Gioacchino A, Procyk J, Molari M, Schreck JS, Zhou Y, Liu Y, Monasson R, Cocco S, Šulc P. Generative and interpretable machine learning for aptamer design and analysis of in vitro sequence selection. PLoS Comput Biol 2022; 18:e1010561. [PMID: 36174101 PMCID: PMC9553063 DOI: 10.1371/journal.pcbi.1010561] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 10/11/2022] [Accepted: 09/12/2022] [Indexed: 12/03/2022] Open
Abstract
Selection protocols such as SELEX, where molecules are selected over multiple rounds for their ability to bind to a target of interest, are popular methods for obtaining binders for diagnostic and therapeutic purposes. We show that Restricted Boltzmann Machines (RBMs), an unsupervised two-layer neural network architecture, can successfully be trained on sequence ensembles from single rounds of SELEX experiments for thrombin aptamers. RBMs assign scores to sequences that can be directly related to their fitnesses estimated through experimental enrichment ratios. Hence, RBMs trained from sequence data at a given round can be used to predict the effects of selection at later rounds. Moreover, the parameters of the trained RBMs are interpretable and identify functional features contributing most to sequence fitness. To exploit the generative capabilities of RBMs, we introduce two different training protocols: one taking into account sequence counts, capable of identifying the few best binders, and another based on unique sequences only, generating more diverse binders. We then use RBMs model to generate novel aptamers with putative disruptive mutations or good binding properties, and validate the generated sequences with gel shift assay experiments. Finally, we compare the RBM’s performance with different supervised learning approaches that include random forests and several deep neural network architectures. We show that two-layer neural networks, Restricted Boltzmann Machines (RBM), can be successfully trained on sequence ensemble datasets from selection-amplification experiments. We train the RBM using datasets from aptamer selection experiments on thrombin protein, and show that the model can successfully generalize to the test set to predict binders and non-binders. The log-likelihood assigned to a sequence by the RBM is correlated with the sequence fitness as quantified by the amplification between different rounds of selection. We further show that that the model is interpretable and by inspecting the weights of the model, we can identify structural motifs that are characteristic of the good binders. We explore the usage of the RBMs to identify which of the possible protein exosites the aptamers bind to. We show that the RBM can also be used for unsupervised clustering. Finally, we use RBMs to generate novel aptamers, and we experimentally verify predicted binding and non-binding sequences generated from the RBM.
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Affiliation(s)
- Andrea Di Gioacchino
- Laboratoire de Physique de l’Ecole Normale Supérieure, PSL & CNRS UMR8063, Sorbonne Université, Université de Paris, Paris, France
| | - Jonah Procyk
- School of Molecular Sciences and Center for Molecular Design and Biomimetics, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Marco Molari
- Laboratoire de Physique de l’Ecole Normale Supérieure, PSL & CNRS UMR8063, Sorbonne Université, Université de Paris, Paris, France
- Biozentrum, University of Basel, Basel, Switzerland
- Swiss Institute of Bioinformatics, Basel, Switzerland
| | - John S. Schreck
- National Center for Atmospheric Research, Computational and Information Systems Laboratory, Boulder, Colorado, United States of America
| | - Yu Zhou
- School of Molecular Sciences and Center for Molecular Design and Biomimetics, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Yan Liu
- School of Molecular Sciences and Center for Molecular Design and Biomimetics, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Rémi Monasson
- Laboratoire de Physique de l’Ecole Normale Supérieure, PSL & CNRS UMR8063, Sorbonne Université, Université de Paris, Paris, France
- * E-mail: (RM); (SC); (PŠ)
| | - Simona Cocco
- Laboratoire de Physique de l’Ecole Normale Supérieure, PSL & CNRS UMR8063, Sorbonne Université, Université de Paris, Paris, France
- * E-mail: (RM); (SC); (PŠ)
| | - Petr Šulc
- School of Molecular Sciences and Center for Molecular Design and Biomimetics, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- * E-mail: (RM); (SC); (PŠ)
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8
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Giarimoglou N, Kouvela A, Maniatis A, Papakyriakou A, Zhang J, Stamatopoulou V, Stathopoulos C. A Riboswitch-Driven Era of New Antibacterials. Antibiotics (Basel) 2022; 11:antibiotics11091243. [PMID: 36140022 PMCID: PMC9495366 DOI: 10.3390/antibiotics11091243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/01/2022] [Accepted: 09/08/2022] [Indexed: 11/26/2022] Open
Abstract
Riboswitches are structured non-coding RNAs found in the 5′ UTR of important genes for bacterial metabolism, virulence and survival. Upon the binding of specific ligands that can vary from simple ions to complex molecules such as nucleotides and tRNAs, riboswitches change their local and global mRNA conformations to affect downstream transcription or translation. Due to their dynamic nature and central regulatory role in bacterial metabolism, riboswitches have been exploited as novel RNA-based targets for the development of new generation antibacterials that can overcome drug-resistance problems. During recent years, several important riboswitch structures from many bacterial representatives, including several prominent human pathogens, have shown that riboswitches are ideal RNA targets for new compounds that can interfere with their structure and function, exhibiting much reduced resistance over time. Most interestingly, mainstream antibiotics that target the ribosome have been shown to effectively modulate the regulatory behavior and capacity of several riboswitches, both in vivo and in vitro, emphasizing the need for more in-depth studies and biological evaluation of new antibiotics. Herein, we summarize the currently known compounds that target several main riboswitches and discuss the role of mainstream antibiotics as modulators of T-box riboswitches, in the dawn of an era of novel inhibitors that target important bacterial regulatory RNAs.
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Affiliation(s)
- Nikoleta Giarimoglou
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
| | - Adamantia Kouvela
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
| | - Alexandros Maniatis
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
| | - Athanasios Papakyriakou
- Institute of Biosciences & Applications, National Centre for Scientific Research “Demokritos”, Ag. Paraskevi, 15341 Athens, Greece
| | - Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | | | - Constantinos Stathopoulos
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
- Correspondence: ; Tel.: +30-2610-997932
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9
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Wyllie JA, McKay MV, Barrow AS, Soares da Costa TP. Biosynthesis of uridine diphosphate N-Acetylglucosamine: An underexploited pathway in the search for novel antibiotics? IUBMB Life 2022; 74:1232-1252. [PMID: 35880704 PMCID: PMC10087520 DOI: 10.1002/iub.2664] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 07/04/2022] [Indexed: 11/06/2022]
Abstract
Although the prevalence of antibiotic resistance is increasing at an alarming rate, there are a dwindling number of effective antibiotics available. Thus, the development of novel antibacterial agents should be of utmost importance. Peptidoglycan biosynthesis has been and is still an attractive source for antibiotic targets; however, there are several components that remain underexploited. In this review, we examine the enzymes involved in the biosynthesis of one such component, UDP-N-acetylglucosamine, an essential building block and precursor of bacterial peptidoglycan. Furthermore, given the presence of a similar biosynthesis pathway in eukaryotes, we discuss the current knowledge on the differences and similarities between the bacterial and eukaryotic enzymes. Finally, this review also summarises the recent advances made in the development of inhibitors targeting the bacterial enzymes.
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Affiliation(s)
- Jessica A Wyllie
- School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Adelaide, South Australia, Australia
| | - Mirrin V McKay
- School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Adelaide, South Australia, Australia
| | - Andrew S Barrow
- School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Adelaide, South Australia, Australia
| | - Tatiana P Soares da Costa
- School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Adelaide, South Australia, Australia
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10
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Andreasson JOL, Savinov A, Block SM, Greenleaf WJ. Comprehensive sequence-to-function mapping of cofactor-dependent RNA catalysis in the glmS ribozyme. Nat Commun 2020; 11:1663. [PMID: 32245964 PMCID: PMC7125110 DOI: 10.1038/s41467-020-15540-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 03/05/2020] [Indexed: 11/24/2022] Open
Abstract
Massively parallel, quantitative measurements of biomolecular activity across sequence space can greatly expand our understanding of RNA sequence-function relationships. We report the development of an RNA-array assay to perform such measurements and its application to a model RNA: the core glmS ribozyme riboswitch, which performs a ligand-dependent self-cleavage reaction. We measure the cleavage rates for all possible single and double mutants of this ribozyme across a series of ligand concentrations, determining kcat and KM values for active variants. These systematic measurements suggest that evolutionary conservation in the consensus sequence is driven by maintenance of the cleavage rate. Analysis of double-mutant rates and associated mutational interactions produces a structural and functional mapping of the ribozyme sequence, revealing the catalytic consequences of specific tertiary interactions, and allowing us to infer structural rearrangements that permit certain sequence variants to maintain activity.
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Affiliation(s)
- Johan O L Andreasson
- Department of Genetics, Stanford University, Stanford, CA, 94305, USA
- Department of Biochemistry, Stanford University, Stanford, CA, 94305, USA
| | - Andrew Savinov
- Biophysics Program, Stanford University, Stanford, CA, 94305, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, 98195, USA
| | - Steven M Block
- Department of Biology, Stanford University, Stanford, CA, 94305, USA.
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA.
| | - William J Greenleaf
- Department of Genetics, Stanford University, Stanford, CA, 94305, USA.
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
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11
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Tamburrini A, Colombo C, Bernardi A. Design and synthesis of glycomimetics: Recent advances. Med Res Rev 2020; 40:495-531. [DOI: 10.1002/med.21625] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 06/06/2019] [Accepted: 07/09/2019] [Indexed: 12/16/2022]
Affiliation(s)
- Alice Tamburrini
- Dipartimento di ChimicaUniversita’ degli Studi di Milano Milano Italy
| | - Cinzia Colombo
- Dipartimento di ChimicaUniversita’ degli Studi di Milano Milano Italy
| | - Anna Bernardi
- Dipartimento di ChimicaUniversita’ degli Studi di Milano Milano Italy
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12
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Pavlova N, Penchovsky R. Genome-wide bioinformatics analysis of FMN, SAM-I, glmS, TPP, lysine, purine, cobalamin, and SAH riboswitches for their applications as allosteric antibacterial drug targets in human pathogenic bacteria. Expert Opin Ther Targets 2019; 23:631-643. [DOI: 10.1080/14728222.2019.1618274] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Nikolet Pavlova
- Department of Genetics, Faculty of Biology, Sofia University “St. Kliment Ohridski”, Sofia, Bulgaria
| | - Robert Penchovsky
- Department of Genetics, Faculty of Biology, Sofia University “St. Kliment Ohridski”, Sofia, Bulgaria
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13
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Parmeciano Di Noto G, Molina MC, Quiroga C. Insights Into Non-coding RNAs as Novel Antimicrobial Drugs. Front Genet 2019; 10:57. [PMID: 30853970 PMCID: PMC6395445 DOI: 10.3389/fgene.2019.00057] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Accepted: 01/24/2019] [Indexed: 12/21/2022] Open
Abstract
Multidrug resistant bacteria are a serious worldwide problem, especially carbapenem-resistant Enterobacteriaceae (such as Klebsiella pneumoniae and Escherichia coli), Acinetobacter baumannii and Pseudomonas aeruginosa. Since the emergence of extensive and pan-drug resistant bacteria there are few antibiotics left to treat patients, thus novel RNA-based strategies are being considered. Here, we examine the current situation of different non-coding RNAs found in bacteria as well as their function and potential application as antimicrobial agents. Furthermore, we discuss the factors that may contribute in the efficient development of RNA-based drugs, the limitations for their implementation and the use of nanocarriers for delivery.
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Affiliation(s)
- Gisela Parmeciano Di Noto
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Tecnológicas, Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPAM), Facultad de Medicina, Buenos Aires, Argentina
| | - María Carolina Molina
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Tecnológicas, Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPAM), Facultad de Medicina, Buenos Aires, Argentina
| | - Cecilia Quiroga
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Tecnológicas, Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPAM), Facultad de Medicina, Buenos Aires, Argentina
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14
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Davies JS, Coombes D, Horne CR, Pearce FG, Friemann R, North RA, Dobson RCJ. Functional and solution structure studies of amino sugar deacetylase and deaminase enzymes from Staphylococcus aureus. FEBS Lett 2018; 593:52-66. [PMID: 30411345 DOI: 10.1002/1873-3468.13289] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 10/25/2018] [Accepted: 10/26/2018] [Indexed: 12/13/2022]
Abstract
N-Acetylglucosamine-6-phosphate deacetylase (NagA) and glucosamine-6-phosphate deaminase (NagB) are branch point enzymes that direct amino sugars into different pathways. For Staphylococcus aureus NagA, analytical ultracentrifugation and small-angle X-ray scattering data demonstrate that it is an asymmetric dimer in solution. Initial rate experiments show hysteresis, which may be related to pathway regulation, and kinetic parameters similar to other bacterial isozymes. The enzyme binds two Zn2+ ions and is not substrate inhibited, unlike the Escherichia coli isozyme. S. aureus NagB adopts a novel dimeric structure in solution and shows kinetic parameters comparable to other Gram-positive isozymes. In summary, these functional data and solution structures are of use for understanding amino sugar metabolism in S. aureus, and will inform the design of inhibitory molecules.
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Affiliation(s)
- James S Davies
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - David Coombes
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Christopher R Horne
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - F Grant Pearce
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Rosmarie Friemann
- Department of Chemistry and Molecular Biology, University of Gothenburg, Sweden.,Centre for Antibiotic Resistance Research (CARe) at University of Gothenburg, Sweden
| | - Rachel A North
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand.,Department of Chemistry and Molecular Biology, University of Gothenburg, Sweden
| | - Renwick C J Dobson
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand.,Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Vic., Australia
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15
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Self-cleavage of the glmS ribozyme core is controlled by a fragile folding element. Proc Natl Acad Sci U S A 2018; 115:11976-11981. [PMID: 30397151 DOI: 10.1073/pnas.1812122115] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Riboswitches modulate gene expression in response to small-molecule ligands. Switching is generally thought to occur via the stabilization of a specific RNA structure conferred by binding the cognate ligand. However, it is unclear whether any such stabilization occurs for riboswitches whose ligands also play functional roles, such as the glmS ribozyme riboswitch, which undergoes self-cleavage using its regulatory ligand, glucosamine 6-phosphate, as a catalytic cofactor. To address this question, it is necessary to determine both the conformational ensemble and its ligand dependence. We used optical tweezers to measure folding dynamics and cleavage rates for the core glmS ribozyme over a range of forces and ligand conditions. We found that the folding of a specific structural element, the P2.2 duplex, controls active-site formation and catalysis. However, the folded state is only weakly stable, regardless of cofactor concentration, supplying a clear exception to the ligand-based stabilization model of riboswitch function.
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16
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Abstract
Riboswitches are cis-acting gene regulatory elements and constitute potential targets for new antibiotics. Recent studies in this field have started to explore these targets for drug discovery. New ligands found by fragment screening, design of analogs of the natural ligands or serendipitously by phenotypic screening have shown antibacterial effects in cell assays against a range of bacteria strains and in animal models. In this review, we highlight the most advanced drug design work of riboswitch ligands and discuss the challenges in the field with respect to the development of antibiotics with a new mechanism of action.
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17
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Matzner D, Schüller A, Seitz T, Wittmann V, Mayer G. Fluoro-Carba-Sugars are Glycomimetic Activators of the glmS Ribozyme. Chemistry 2017; 23:12604-12612. [PMID: 28661578 DOI: 10.1002/chem.201702371] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Indexed: 11/05/2022]
Abstract
The glmS ribozyme is a bacterial gene-regulating riboswitch that controls cell wall synthesis, depending on glucosamine-6-phosphate as a cofactor. Due to the presence of this ribozyme in several human pathogen bacteria (e.g., MRSA, VRSA), the glmS ribozyme represents an attractive target for the development of artificial cofactors. The substitution of the ring oxygen in carbohydrates by functionalized methylene groups leads to a new generation of glycomimetics that exploits distinct interaction possibilities with their target structure in biological systems. Herein, we describe the synthesis of mono-fluoro-modified carba variants of α-d-glucosamine and β-l-idosamine. (5aR)-Fluoro-carba-α-d-glucosamine-6-phosphate is a synthetic mimic of the natural ligand of the glmS ribozyme and is capable of effectively addressing its unique self-cleavage mechanism. However, in contrast to what was expected, the activity is significantly decreased compared to its non-fluorinated analog. By combining self-cleavage assays with the Bacillus subtilis and Staphylococcus aureus glmS ribozyme and molecular docking studies, we provide a structure-activity relationship for fluorinated carba-sugars.
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Affiliation(s)
- Daniel Matzner
- Life & Medical Sciences Institute, University of Bonn, Gerhard-Domagk-Str. 1, 53121, Bonn, Germany
| | - Anna Schüller
- Life & Medical Sciences Institute, University of Bonn, Gerhard-Domagk-Str. 1, 53121, Bonn, Germany
| | - Torben Seitz
- Department of Chemistry, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany.,Current address: Cilag AG, Schaffhausen, Switzerland
| | - Valentin Wittmann
- Department of Chemistry, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany
| | - Günter Mayer
- Life & Medical Sciences Institute, University of Bonn, Gerhard-Domagk-Str. 1, 53121, Bonn, Germany
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18
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Dersch P, Khan MA, Mühlen S, Görke B. Roles of Regulatory RNAs for Antibiotic Resistance in Bacteria and Their Potential Value as Novel Drug Targets. Front Microbiol 2017; 8:803. [PMID: 28529506 PMCID: PMC5418344 DOI: 10.3389/fmicb.2017.00803] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 04/19/2017] [Indexed: 01/23/2023] Open
Abstract
The emergence of antibiotic resistance mechanisms among bacterial pathogens increases the demand for novel treatment strategies. Lately, the contribution of non-coding RNAs to antibiotic resistance and their potential value as drug targets became evident. RNA attenuator elements in mRNA leader regions couple expression of resistance genes to the presence of the cognate antibiotic. Trans-encoded small RNAs (sRNAs) modulate antibiotic tolerance by base-pairing with mRNAs encoding functions important for resistance such as metabolic enzymes, drug efflux pumps, or transport proteins. Bacteria respond with extensive changes of their sRNA repertoire to antibiotics. Each antibiotic generates a unique sRNA profile possibly causing downstream effects that may help to overcome the antibiotic challenge. In consequence, regulatory RNAs including sRNAs and their protein interaction partners such as Hfq may prove useful as targets for antimicrobial chemotherapy. Indeed, several compounds have been developed that kill bacteria by mimicking ligands for riboswitches controlling essential genes, demonstrating that regulatory RNA elements are druggable targets. Drugs acting on sRNAs are considered for combined therapies to treat infections. In this review, we address how regulatory RNAs respond to and establish resistance to antibiotics in bacteria. Approaches to target RNAs involved in intrinsic antibiotic resistance or virulence for chemotherapy will be discussed.
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Affiliation(s)
- Petra Dersch
- Department of Molecular Infection Biology, Helmholtz Centre for Infection ResearchBraunschweig, Germany
| | - Muna A Khan
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of ViennaVienna, Austria
| | - Sabrina Mühlen
- Department of Molecular Infection Biology, Helmholtz Centre for Infection ResearchBraunschweig, Germany
| | - Boris Görke
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of ViennaVienna, Austria
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