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Zhan X, Wilson TJ, Li Z, Zhang J, Yang Y, Lilley DMJ, Liu Y. The structure and catalytic mechanism of a pseudoknot-containing hammerhead ribozyme. Nat Commun 2024; 15:6628. [PMID: 39103372 DOI: 10.1038/s41467-024-50892-y] [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: 03/10/2024] [Accepted: 07/22/2024] [Indexed: 08/07/2024] Open
Abstract
We have determined the crystal structure of a pseudoknot (PK)-containing hammerhead ribozyme that closely resembles the pistol ribozyme, with essentially identical secondary structure and connectivity. The activity is more sensitive to deletion of the G8 2'OH than to the absence of magnesium ions, indicating that the catalytic mechanism is the same as the extended hammerhead, and distinct from the pistol ribozyme. Here we show that nucleophilic attack is almost perfectly in-line, and the G8 2'OH is well positioned to act as general acid, being directed towards the O5' leaving group, and 2.9 Å away from it. Despite the similarity in overall structure to the pistol ribozyme, the local structure close to the cleavage site differs, and the PK hammerhead retains its unique mechanistic identity and demonstrates enhanced activity over other hammerhead ribozymes under standard conditions.
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Affiliation(s)
- Xuelin Zhan
- State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for Cell Responses, Nankai University, Tianjin, China
- College of Pharmacy, Nankai University, Tianjin, China
- China Regional Research Centre, International Centre of Genetic Engineering and Biotechnology, Taizhou, P. R. China
| | - Timothy J Wilson
- Division of Molecular, Cellular and Developmental Biology, The University of Dundee, Dundee, UK
| | - Zhenzhen Li
- State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for Cell Responses, Nankai University, Tianjin, China
- College of Pharmacy, Nankai University, Tianjin, China
| | - Jingjing Zhang
- State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for Cell Responses, Nankai University, Tianjin, China
- College of Pharmacy, Nankai University, Tianjin, China
| | - Yili Yang
- China Regional Research Centre, International Centre of Genetic Engineering and Biotechnology, Taizhou, P. R. China
| | - David M J Lilley
- Division of Molecular, Cellular and Developmental Biology, The University of Dundee, Dundee, UK.
- Visiting Professor, Nankai University, Tianjin, China.
| | - Yijin Liu
- State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for Cell Responses, Nankai University, Tianjin, China.
- College of Pharmacy, Nankai University, Tianjin, China.
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2
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Wieruszewska J, Pawłowicz A, Połomska E, Pasternak K, Gdaniec Z, Andrałojć W. The 8-17 DNAzyme can operate in a single active structure regardless of metal ion cofactor. Nat Commun 2024; 15:4218. [PMID: 38760331 PMCID: PMC11101458 DOI: 10.1038/s41467-024-48638-x] [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: 04/13/2023] [Accepted: 05/09/2024] [Indexed: 05/19/2024] Open
Abstract
DNAzymes - synthetic enzymes made of DNA - have long attracted attention as RNA-targeting therapeutic agents. Yet, as of now, no DNAzyme-based drug has been approved, partially due to our lacking understanding of their molecular mode of action. In this work we report the solution structure of 8-17 DNAzyme bound to a Zn2+ ion solved through NMR spectroscopy. Surprisingly, it turned out to be very similar to the previously solved Pb2+-bound form (catalytic domain RMSD = 1.28 Å), despite a long-standing literature consensus that Pb2+ recruits a different DNAzyme fold than other metal ion cofactors. Our follow-up NMR investigations in the presence of other ions - Mg2+, Na+, and Pb2+ - suggest that at DNAzyme concentrations used in NMR all these ions induce a similar tertiary fold. Based on these findings, we propose a model for 8-17 DNAzyme interactions with metal ions postulating the existence of only a single catalytically-active structure, yet populated to a different extent depending on the metal ion cofactor. Our results provide structural information on the 8-17 DNAzyme in presence of non-Pb2+ cofactors, including the biologically relevant Mg2+ ion.
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Affiliation(s)
- Julia Wieruszewska
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704, Poznań, Noskowskiego, 12/14, Poland
| | - Aleksandra Pawłowicz
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704, Poznań, Noskowskiego, 12/14, Poland
| | - Ewa Połomska
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704, Poznań, Noskowskiego, 12/14, Poland
| | - Karol Pasternak
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704, Poznań, Noskowskiego, 12/14, Poland
| | - Zofia Gdaniec
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704, Poznań, Noskowskiego, 12/14, Poland
| | - Witold Andrałojć
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704, Poznań, Noskowskiego, 12/14, Poland.
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3
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Zhang Y, Zhang J, Wan H, Wu Z, Xu H, Zhang Z, Wang Y, Wang J. New Insights into the Dependence of CPEB3 Ribozyme Cleavage on Mn 2+ and Mg 2. J Phys Chem Lett 2024; 15:2708-2714. [PMID: 38427973 DOI: 10.1021/acs.jpclett.3c03221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2024]
Abstract
CPEB3 ribozyme is a self-cleaving RNA that occurs naturally in mammals and requires divalent metal ions for efficient activity. Ribozymes exhibit preferences for specific metal ions, but the exact differences in the catalytic mechanisms of various metal ions on the CPEB3 ribozyme remain unclear. Our findings reveal that Mn2+ functions as a more effective cofactor for CPEB3 ribozyme catalysis compared to Mg2+, as confirmed by its stronger binding affinity to CPEB3 by EPR. Cleavage assays of CPEB3 mutants and molecular docking analyses further showed that excessive Mn2+ ions can bind to a second binding site near the catalytic site, hindering CPEB3 catalytic efficiency and contributing to the Mn2+ bell-shaped curve. These results implicate a pivotal role for the local nucleobase-Mn2+ interactions in facilitating RNA folding and modulating the directed attack of nucleophilic reagents. Our study provides new insights and experimental evidence for exploring the divalent cation dependent cleavage mechanism of the CPEB3 ribozyme.
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Affiliation(s)
- Yaoyao Zhang
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jing Zhang
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Hengjia Wan
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ziwei Wu
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Huangtao Xu
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Zhe Zhang
- Institute for Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen 518055, China
| | - Yujuan Wang
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- International Magnetobiology Frontier Research Center (iMFRC), Science Island, Hefei 230031, China
| | - Junfeng Wang
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- University of Science and Technology of China, Hefei, Anhui 230026, China
- School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui 230032, China
- International Magnetobiology Frontier Research Center (iMFRC), Science Island, Hefei 230031, China
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4
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Schneider B, Sweeney BA, Bateman A, Cerny J, Zok T, Szachniuk M. When will RNA get its AlphaFold moment? Nucleic Acids Res 2023; 51:9522-9532. [PMID: 37702120 PMCID: PMC10570031 DOI: 10.1093/nar/gkad726] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 08/13/2023] [Accepted: 08/22/2023] [Indexed: 09/14/2023] Open
Abstract
The protein structure prediction problem has been solved for many types of proteins by AlphaFold. Recently, there has been considerable excitement to build off the success of AlphaFold and predict the 3D structures of RNAs. RNA prediction methods use a variety of techniques, from physics-based to machine learning approaches. We believe that there are challenges preventing the successful development of deep learning-based methods like AlphaFold for RNA in the short term. Broadly speaking, the challenges are the limited number of structures and alignments making data-hungry deep learning methods unlikely to succeed. Additionally, there are several issues with the existing structure and sequence data, as they are often of insufficient quality, highly biased and missing key information. Here, we discuss these challenges in detail and suggest some steps to remedy the situation. We believe that it is possible to create an accurate RNA structure prediction method, but it will require solving several data quality and volume issues, usage of data beyond simple sequence alignments, or the development of new less data-hungry machine learning methods.
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Affiliation(s)
- Bohdan Schneider
- Institute of Biotechnology of the Czech Academy of Sciences, Prumyslova 595, CZ-252 50 Vestec, Czech Republic
| | - Blake Alexander Sweeney
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, CB10 1SD, UK
| | - Alex Bateman
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, CB10 1SD, UK
| | - Jiri Cerny
- Institute of Biotechnology of the Czech Academy of Sciences, Prumyslova 595, CZ-252 50 Vestec, Czech Republic
| | - Tomasz Zok
- Institute of Computing Science and European Centre for Bioinformatics and Genomics, Poznan University of Technology, Piotrowo 2, 60-965 Poznan, Poland
| | - Marta Szachniuk
- Institute of Computing Science and European Centre for Bioinformatics and Genomics, Poznan University of Technology, Piotrowo 2, 60-965 Poznan, Poland
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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5
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Yoon S, Ollie E, York DM, Piccirilli JA, Harris ME. Rapid Kinetics of Pistol Ribozyme: Insights into Limits to RNA Catalysis. Biochemistry 2023. [PMID: 37294744 DOI: 10.1021/acs.biochem.3c00160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Pistol ribozyme (Psr) is a distinct class of small endonucleolytic ribozymes, which are important experimental systems for defining fundamental principles of RNA catalysis and designing valuable tools in biotechnology. High-resolution structures of Psr, extensive structure-function studies, and computation support a mechanism involving one or more catalytic guanosine nucleobases acting as a general base and divalent metal ion-bound water acting as an acid to catalyze RNA 2'-O-transphosphorylation. Yet, for a wide range of pH and metal ion concentrations, the rate of Psr catalysis is too fast to measure manually and the reaction steps that limit catalysis are not well understood. Here, we use stopped-flow fluorescence spectroscopy to evaluate Psr temperature dependence, solvent H/D isotope effects, and divalent metal ion affinity and specificity unconstrained by limitations due to fast kinetics. The results show that Psr catalysis is characterized by small apparent activation enthalpy and entropy changes and minimal transition state H/D fractionation, suggesting that one or more pre-equilibrium steps rather than chemistry is rate limiting. Quantitative analyses of divalent ion dependence confirm that metal aquo ion pKa correlates with higher rates of catalysis independent of differences in ion binding affinity. However, ambiguity regarding the rate-limiting step and similar correlation with related attributes such as ionic radius and hydration free energy complicate a definitive mechanistic interpretation. These new data provide a framework for further interrogation of Psr transition state stabilization and show how thermal instability, metal ion insolubility at optimal pH, and pre-equilibrium steps such as ion binding and folding limit the catalytic power of Psr suggesting potential strategies for further optimization.
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Affiliation(s)
- Suhyun Yoon
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - Edward Ollie
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - Darrin M York
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Joseph A Piccirilli
- Department of Chemistry and Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637, United States
| | - Michael E Harris
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
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6
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Assmann SM, Chou HL, Bevilacqua PC. Rock, scissors, paper: How RNA structure informs function. THE PLANT CELL 2023; 35:1671-1707. [PMID: 36747354 DOI: 10.1093/plcell/koad026] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 01/05/2023] [Accepted: 01/30/2023] [Indexed: 05/30/2023]
Abstract
RNA can fold back on itself to adopt a wide range of structures. These range from relatively simple hairpins to intricate 3D folds and can be accompanied by regulatory interactions with both metabolites and macromolecules. The last 50 yr have witnessed elucidation of an astonishing array of RNA structures including transfer RNAs, ribozymes, riboswitches, the ribosome, the spliceosome, and most recently entire RNA structuromes. These advances in RNA structural biology have deepened insight into fundamental biological processes including gene editing, transcription, translation, and structure-based detection and response to temperature and other environmental signals. These discoveries reveal that RNA can be relatively static, like a rock; that it can have catalytic functions of cutting bonds, like scissors; and that it can adopt myriad functional shapes, like paper. We relate these extraordinary discoveries in the biology of RNA structure to the plant way of life. We trace plant-specific discovery of ribozymes and riboswitches, alternative splicing, organellar ribosomes, thermometers, whole-transcriptome structuromes and pan-structuromes, and conclude that plants have a special set of RNA structures that confer unique types of gene regulation. We finish with a consideration of future directions for the RNA structure-function field.
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Affiliation(s)
- Sarah M Assmann
- Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
- Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Hong-Li Chou
- Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Philip C Bevilacqua
- Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
- Department of Chemistry, Pennsylvania State University, University Park, PA 16802, USA
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
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7
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Czapik T, Piasecka J, Kierzek R, Kierzek E. Structural variants and modifications of hammerhead ribozymes targeting influenza A virus conserved structural motifs. MOLECULAR THERAPY - NUCLEIC ACIDS 2022; 29:64-74. [PMID: 35784013 PMCID: PMC9217987 DOI: 10.1016/j.omtn.2022.05.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 05/26/2022] [Indexed: 11/16/2022]
Abstract
The naturally occurring structure and biological functions of RNA are correlated, which includes hammerhead ribozymes. We proposed new variants of hammerhead ribozymes targeting conserved structural motifs of segment 5 of influenza A virus (IAV) (+)RNA. The variants carry structural and chemical modifications aiming to improve the RNA cleavage activity of ribozymes. We introduced an additional hairpin motif and attempted to select ribozyme-target pairs with sequence features that enable the potential formation of the trans-Hoogsteen interactions that are present in full-length, highly active hammerhead ribozymes. We placed structurally defined guanosine analogs into the ribozyme catalytic core. Herein, the significantly improved synthesis of 2′-deoxy-2′-fluoroarabinoguanosine derivatives is described. The most potent hammerhead ribozymes were applied to chimeric short hairpin RNA (shRNA)-ribozyme plasmid constructs to improve the antiviral activity of the two components. The modified hammerhead ribozymes showed moderate cleavage activity. Treatment of IAV-infected Madin-Darby canine kidney (MDCK) cells with the plasmid constructs resulted in significant inhibition of virus replication. Real-time PCR analysis revealed a significant (80%–88%) reduction in viral RNA when plasmids carriers were used. A focus formation assay (FFA) for chimeric plasmids showed inhibition of virus replication by 1.6–1.7 log10 units, whereas the use of plasmids carrying ribozymes or shRNAs alone resulted in lower inhibition.
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8
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Ekesan Ş, McCarthy E, Case DA, York DM. RNA Electrostatics: How Ribozymes Engineer Active Sites to Enable Catalysis. J Phys Chem B 2022; 126:5982-5990. [PMID: 35862934 PMCID: PMC9496635 DOI: 10.1021/acs.jpcb.2c03727] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Electrostatic interactions are fundamental to RNA structure and function, and intimately influenced by solvation and the ion atmosphere. RNA enzymes, or ribozymes, are catalytic RNAs that are able to enhance reaction rates over a million-fold, despite having only a limited repertoire of building blocks and available set of chemical functional groups. Ribozyme active sites usually occur at junctions where negatively charged helices come together, and in many cases leverage this strained electrostatic environment to recruit metal ions in solution that can assist in catalysis. Similar strategies have been implicated in related artificially engineered DNA enzymes. Herein, we apply Poisson-Boltzmann, 3D-RISM, and molecular simulations to study a set of metal-dependent small self-cleaving ribozymes (hammerhead, pistol, and Varkud satellite) as well as an artificially engineered DNAzyme (8-17) to examine electrostatic features and their relation to the recruitment of monovalent and divalent metal ions important for activity. We examine several fundamental roles for these ions that include: (1) structural integrity of the catalytically active state, (2) pKa tuning of residues involved in acid-base catalysis, and (3) direct electrostatic stabilization of the transition state via Lewis acid catalysis. Taken together, these examples demonstrate how RNA electrostatics orchestrates the site-specific and territorial binding of metal ions to play important roles in catalysis.
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Affiliation(s)
- Şölen Ekesan
- Laboratory for Biomolecular Simulation Research, Institute for Quantitative Biomedicine and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Erika McCarthy
- Laboratory for Biomolecular Simulation Research, Institute for Quantitative Biomedicine and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - David A. Case
- Laboratory for Biomolecular Simulation Research, Institute for Quantitative Biomedicine and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Darrin M. York
- Laboratory for Biomolecular Simulation Research, Institute for Quantitative Biomedicine and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
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9
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Ekesan Ş, York DM. Who stole the proton? Suspect general base guanine found with a smoking gun in the pistol ribozyme. Org Biomol Chem 2022; 20:6219-6230. [PMID: 35452066 PMCID: PMC9378597 DOI: 10.1039/d2ob00234e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The pistol ribozyme (Psr) is one among the most recently discovered classes of small nucleolytic ribozymes that catalyze site-specific RNA self-cleavage through 2'-O-transphosphorylation. The Psr contains a conserved guanine (G40) that in crystal structures is in a position suggesting it plays the role of the general base to abstract a proton from the nucleophile to activate the reaction. Although some functional data is consistent with this mechanistic role, a notable exception is 2-aminopurine (2AP) substitution which has no effect on the rate, unlike similar substitutions across other so-called "G + M" and "G + A" ribozyme classes. Herein we postulate that an alternate conserved guanine, G42, is the primary general base, and provide evidence from molecular simulations that the active site of Psr can undergo local refolding into a structure that is consistent with the common "L-platform/L-scaffold" architecture identified in G + M and G + A ribozyme classes with Psr currently the notable exception. We summarize the key currently available experimental data and present new classical and combined quantum mechanical/molecular mechanical simulation results that collectively suggest a new hypothesis. We hypothesize that there are two available catalytic pathways supported by different conformational states connected by a local refolding of the active site: (1) a primary pathway with an active site architecture aligned with the L-platform/L-scaffold framework where G42 acts as a general base, and (2) a secondary pathway with the crystallographic active site architecture where G40 acts as a general base. We go on to make several experimentally testable predictions, and suggest specific experiments that would ultimately bring closure to the mystery as to "who stole the proton in the pistol ribozyme?".
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Affiliation(s)
- Şölen Ekesan
- Laboratory for Biomolecular Simulation Research, Institute for Quantitative Biomedicine and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA.
| | - Darrin M York
- Laboratory for Biomolecular Simulation Research, Institute for Quantitative Biomedicine and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA.
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10
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Parra-Meneses V, Rojas-Hernández F, Cepeda-Plaza M. The role of Na + in catalysis by the 8-17 DNAzyme. Org Biomol Chem 2022; 20:6356-6362. [PMID: 35856910 DOI: 10.1039/d2ob01075e] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The 8-17 DNAzyme is the most studied deoxyribozyme in terms of its molecular mechanism; hence it has become a model system to understand the basis behind DNA catalysis. New functional studies and the recent attainment of high-resolution X-ray structures, in addition to theoretical calculations have offered a great opportunity to gain a broader comprehension of its mechanism; however many aspects are unclear yet, especially regarding the precise role of metal ions in catalysis. Recently, molecular dynamics simulations have suggested for the first time a specific and dynamical participation of Na+ in the mechanism through the reaction pathway, besides the roles proposed for divalent metal cofactors. Herein, we present experimental evidence of a cooperative role of the monovalent cation Na+ in catalysis that is in line with these theoretical suggestions. Our findings show a clear influence of the concentration of Na+ on the activity of the 8-17 DNAzyme when Pb2+ is used as the cofactor. Interestingly, this effect is not noticed with Mg2+, indicating a particular contribution of the monovalent ion to catalysis that would operate preferentially with Pb2+. We have also found that Na+ affects the pKa of the general base and the general acid, indicating its influence on general acid-base catalysis, already identified as part of the mechanism of the 8-17 DNAzyme. Finally, our results emphasize the need to consider Na+ carefully in the design and analysis of functional studies of catalytic DNAs and its possible specific role in their mechanisms.
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11
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Lönnberg H. Structural modifications as tools in mechanistic studies of the cleavage of RNA phosphodiester linkages. CHEM REC 2022; 22:e202200141. [PMID: 35832010 DOI: 10.1002/tcr.202200141] [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: 05/16/2022] [Revised: 06/28/2022] [Indexed: 11/06/2022]
Abstract
The cleavage of RNA phosphodiester bonds by RNase A and hammerhead ribozyme at neutral pH fundamentally differs from the spontaneous reactions of these bonds under the same conditions. While the predominant spontaneous reaction is isomerization of the 3',5'-phosphodiester linkages to their 2',5'-counterparts, this reaction has never been reported to compete with the enzymatic cleavage reaction, not even as a minor side reaction. Comparative kinetic measurements with structurally modified di-nucleoside monophosphates and oligomeric phosphodiesters have played an important role in clarification of mechanistic details of the buffer-independent and buffer-catalyzed reactions. More recently, heavy atom isotope effects and theoretical calculations have refined the picture. The primary aim of all these studies has been to form a solid basis for mechanistic analyses of the action of more complicated catalytic machineries. In other words, to contribute to conception of a plausible unified picture of RNA cleavage by biocatalysts, such as RNAse A, hammerhead ribozyme and DNAzymes. In addition, structurally modified trinucleoside monophosphates as transition state models for Group I and II introns have clarified some features of the action of large ribozymes.
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Affiliation(s)
- Harri Lönnberg
- Department of Chemistry, University of Turku, FI-20014 University of, Turku
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12
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Hunsicker-Wang LM, Vogt MJ, Hoogstraten CG, Cosper NJ, Davenport AM, Hendon CH, Scott RA, Britt RD, DeRose VJ. Spectroscopic characterization of Mn2+ and Cd2+ coordination to phosphorothioates in the conserved A9 metal site of the hammerhead ribozyme. J Inorg Biochem 2022; 230:111754. [DOI: 10.1016/j.jinorgbio.2022.111754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 01/28/2022] [Accepted: 02/04/2022] [Indexed: 11/25/2022]
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13
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Peng H, Latifi B, Müller S, Lupták A, Chen IA. Self-cleaving ribozymes: substrate specificity and synthetic biology applications. RSC Chem Biol 2021; 2:1370-1383. [PMID: 34704043 PMCID: PMC8495972 DOI: 10.1039/d0cb00207k] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 06/14/2021] [Indexed: 12/22/2022] Open
Abstract
Various self-cleaving ribozymes appearing in nature catalyze the sequence-specific intramolecular cleavage of RNA and can be engineered to catalyze cleavage of appropriate substrates in an intermolecular fashion, thus acting as true catalysts. The mechanisms of the small, self-cleaving ribozymes have been extensively studied and reviewed previously. Self-cleaving ribozymes can possess high catalytic activity and high substrate specificity; however, substrate specificity is also engineerable within the constraints of the ribozyme structure. While these ribozymes share a common fundamental catalytic mechanism, each ribozyme family has a unique overall architecture and active site organization, indicating that several distinct structures yield this chemical activity. The multitude of catalytic structures, combined with some flexibility in substrate specificity within each family, suggests that such catalytic RNAs, taken together, could access a wide variety of substrates. Here, we give an overview of 10 classes of self-cleaving ribozymes and capture what is understood about their substrate specificity and synthetic applications. Evolution of these ribozymes in an RNA world might be characterized by the emergence of a new ribozyme family followed by rapid adaptation or diversification for specific substrates. Self-cleaving ribozymes have become important tools of synthetic biology. Here we summarize the substrate specificity and applications of the main classes of these ribozymes.![]()
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Affiliation(s)
- Huan Peng
- Department of Chemical and Biomolecular Engineering, University of California Los Angeles CA 90095 USA
| | - Brandon Latifi
- Department of Pharmaceutical Sciences, University of California Irvine CA 92697 USA
| | - Sabine Müller
- Institute for Biochemistry, University Greifswald 17487 Greifswald Germany
| | - Andrej Lupták
- Department of Pharmaceutical Sciences, University of California Irvine CA 92697 USA
| | - Irene A Chen
- Department of Chemical and Biomolecular Engineering, University of California Los Angeles CA 90095 USA
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14
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Abstract
AbstractRibozymes are huge complex biological catalysts composed of a combination of RNA and proteins. Nevertheless, there is a reduced number of small ribozymes, the self-cleavage ribozymes, that are formed just by RNA and, apparently, they existed in cells of primitive biological systems. Unveiling the details of these “fossils” enzymes can contribute not only to the understanding of the origins of life but also to the development of new simplified artificial enzymes. A computational study of the reactivity of the pistol ribozyme carried out by means of classical MD simulations and QM/MM hybrid calculations is herein presented to clarify its catalytic mechanism. Analysis of the geometries along independent MD simulations with different protonation states of the active site basic species reveals that only the canonical system, with no additional protonation changes, renders reactive conformations. A change in the coordination sphere of the Mg2+ ion has been observed during the simulations, which allows proposing a mechanism to explain the unique mode of action of the pistol ribozyme by comparison with other ribozymes. The present results are at the center of the debate originated from recent experimental and theoretical studies on pistol ribozyme.
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15
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Cortés-Guajardo C, Rojas-Hernández F, Paillao-Bustos R, Cepeda-Plaza M. Hydrated metal ion as a general acid in the catalytic mechanism of the 8-17 DNAzyme. Org Biomol Chem 2021; 19:5395-5402. [PMID: 34047747 DOI: 10.1039/d1ob00366f] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The RNA-cleaving 8-17 DNAzyme, which is a metalloenzyme that depends on divalent metal ions for its function, is the most studied catalytic DNA in terms of its mechanism. By the end of 2017, a report of the crystal structure of the enzyme-substrate complex in the presence of Pb2+ probed some of the previous findings and opened new questions, especially around the participation of the metal ion in the catalytic mechanism and the promiscuity exhibited by the enzyme in terms of the metal cofactor required for catalysis. In this article we explore the role of the divalent metal ion in the mechanism of the 8-17 DNAzyme as a general acid, by measuring the influence of pH over the activity of a slower variant of the enzyme in the presence of Pb2+. We replaced G14, which has been identified as a general base in the mechanism of the enzyme, by the unnatural analog 2-aminopurine, with a lower pKa value of the N1 group. With this approach, we obtained a bell-shaped pH-rate profile with experimental pKa values of 5.4 and 7.0. Comparing these results with previous pH-rate profiles in the presence of Mg2+, our findings suggest the stabilization of the 5'-O leaving group by the hydrated metal ion acting as a general acid, in addition to the activation of the 2'-OH nucleophile by the general base G14.
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16
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Moon WJ, Huang PJJ, Liu J. Probing Metal-Dependent Phosphate Binding for the Catalysis of the 17E DNAzyme. Biochemistry 2021; 60:1909-1918. [PMID: 34106684 DOI: 10.1021/acs.biochem.1c00091] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The RNA-cleaving 17E DNAzyme exhibits different levels of cleavage activity in the presence of various divalent metal ions, with Pb2+ giving the fastest cleavage. In this study, the metal-phosphate interaction is probed to understand the trend of activity with different metal ions. For the first-row transition metals, the lowest activity shown by Ni2+ correlates with the inhibition by the inorganic phosphate and its water ligand exchange rate, suggesting inner-sphere metal coordination. Cleavage activity with the two stereoisomers of the phosphorothioate-modified substrates, Rp and Sp, indicated that Mg2+, Mn2+, Fe2+, and Co2+ had the highest Sp:Rp activity ratio of >900. Comparatively, the activity was much less affected using the thiophilic metals, including Pb2+, suggesting inner-sphere coordination. The pH-rate profiles showed that Pb2+ was different than the rest of the metal ions in having a smaller slope and a similar fitted apparent pKa and the pKa of metal-bound water. Combining previous reports and our current results, we propose that Pb2+ most likely plays the role of a general acid while the other metal ions are Lewis acid catalysts interacting with the scissile phosphate.
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Affiliation(s)
- Woohyun J Moon
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Po-Jung Jimmy Huang
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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17
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DasGupta S, Piccirilli JA. The Varkud Satellite Ribozyme: A Thirty-Year Journey through Biochemistry, Crystallography, and Computation. Acc Chem Res 2021; 54:2591-2602. [PMID: 33974386 DOI: 10.1021/acs.accounts.1c00052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The discovery of catalytic RNAs or ribozymes introduced a new class of enzymes to biology. In addition to their increasingly important roles in modern life, ribozymes are key players in the RNA World hypothesis, which posits that life started or flourished with RNA supporting both genetic and enzymatic functions. Therefore, investigations into the mechanisms of ribozyme function provide an exciting opportunity to examine the foundational principles of biological catalysis. Ribozymes are also attractive model systems to investigate the relationship between structure and function in RNA. Endonucleolytic ribozymes represent the largest class of catalytic RNA, of which the Varkud satellite (VS) ribozyme is structurally the most complex. The last ribozyme to be discovered by accident, the VS ribozyme had eluded structural determination for over two decades. When we solved the first crystal structures of the VS ribozyme, an extensive body of biochemical and biophysical data had accumulated over the years with which we could evaluate the functional relevance of the structure. Conversely, the structures provided a new perspective from which to reexamine the functional data and test new hypotheses. The VS ribozyme is organized in a modular fashion where independently folding domains assemble into the active conformation of the ribozyme via three-way junctions. Structures of the VS ribozyme in complex with its substrate at different stages of activation enabled us to map the structural reorganization of the substrate that must precede catalysis. In addition to defining the global architecture of the RNA, the essential interactions between the substrate and catalytic domains, and the rearrangements in the substrate prior to catalysis, these structures provided detailed snapshots of the ribozyme active site, revealing potential catalytic interactions. High resolution structures of the active site bolstered the view that the catalytic mechanism involved nucleobase-mediated general acid-base catalysis and uncovered additional catalytic interactions between the cleavage site and catalytic residues. Informed by the crystal structures of the VS ribozyme, an integrated experimental and computational approach identified the key players and essential interactions that define the active site of the ribozyme. This confluence of biochemical, structural, and computational studies revealed the catalytic mechanism of the ribozyme at unprecedented detail. Additionally, comparative analyses of the active site structures of the VS ribozyme and other nucleic acid-based endoribonucleases revealed common architectural motifs and strikingly similar catalytic strategies. In this Account, we document the progress of VS ribozyme research starting from its discovery and extending to the elucidation of its detailed catalytic mechanism 30 years later.
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Affiliation(s)
- Saurja DasGupta
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, Massachusetts 02114, United States
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States
- Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, United States
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18
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Abstract
RNA enzymes or ribozymes catalyze some of the most important reactions in biology and are thought to have played a central role in the origin and evolution of life on earth. Catalytic function in RNA has evolved in crowded cellular environments that are different from dilute solutions in which most in vitro assays are performed. The presence of molecules such as amino acids, polypeptides, alcohols, and sugars in the cell introduces forces that modify the kinetics and thermodynamics of ribozyme-catalyzed reactions. Synthetic molecules are routinely used in in vitro studies to better approximate the properties of biomolecules under in vivo conditions. This review discusses the various forces that operate within simulated crowded solutions in the context of RNA structure, folding, and catalysis. It also explores ideas about how crowding could have been beneficial to the evolution of functional RNAs and the development of primitive cellular systems in a prebiotic milieu.
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Affiliation(s)
- Saurja DasGupta
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
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19
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Micura R, Höbartner C. Fundamental studies of functional nucleic acids: aptamers, riboswitches, ribozymes and DNAzymes. Chem Soc Rev 2020; 49:7331-7353. [PMID: 32944725 DOI: 10.1039/d0cs00617c] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
This review aims at juxtaposing common versus distinct structural and functional strategies that are applied by aptamers, riboswitches, and ribozymes/DNAzymes. Focusing on recently discovered systems, we begin our analysis with small-molecule binding aptamers, with emphasis on in vitro-selected fluorogenic RNA aptamers and their different modes of ligand binding and fluorescence activation. Fundamental insights are much needed to advance RNA imaging probes for detection of exo- and endogenous RNA and for RNA process tracking. Secondly, we discuss the latest gene expression-regulating mRNA riboswitches that respond to the alarmone ppGpp, to PRPP, to NAD+, to adenosine and cytidine diphosphates, and to precursors of thiamine biosynthesis (HMP-PP), and we outline new subclasses of SAM and tetrahydrofolate-binding RNA regulators. Many riboswitches bind protein enzyme cofactors that, in principle, can catalyse a chemical reaction. For RNA, however, only one system (glmS ribozyme) has been identified in Nature thus far that utilizes a small molecule - glucosamine-6-phosphate - to participate directly in reaction catalysis (phosphodiester cleavage). We wonder why that is the case and what is to be done to reveal such likely existing cellular activities that could be more diverse than currently imagined. Thirdly, this brings us to the four latest small nucleolytic ribozymes termed twister, twister-sister, pistol, and hatchet as well as to in vitro selected DNA and RNA enzymes that promote new chemistry, mainly by exploiting their ability for RNA labelling and nucleoside modification recognition. Enormous progress in understanding the strategies of nucleic acids catalysts has been made by providing thorough structural fundaments (e.g. first structure of a DNAzyme, structures of ribozyme transition state mimics) in combination with functional assays and atomic mutagenesis.
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Affiliation(s)
- Ronald Micura
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck CMBI, Leopold-Franzens University Innsbruck, Innsbruck, Austria.
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20
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Watkins AM, Rangan R, Das R. FARFAR2: Improved De Novo Rosetta Prediction of Complex Global RNA Folds. Structure 2020; 28:963-976.e6. [PMID: 32531203 PMCID: PMC7415647 DOI: 10.1016/j.str.2020.05.011] [Citation(s) in RCA: 106] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 04/27/2020] [Accepted: 05/20/2020] [Indexed: 01/01/2023]
Abstract
Predicting RNA three-dimensional structures from sequence could accelerate understanding of the growing number of RNA molecules being discovered across biology. Rosetta's Fragment Assembly of RNA with Full-Atom Refinement (FARFAR) has shown promise in community-wide blind RNA-Puzzle trials, but lack of a systematic and automated benchmark has left unclear what limits FARFAR performance. Here, we benchmark FARFAR2, an algorithm integrating RNA-Puzzle-inspired innovations with updated fragment libraries and helix modeling. In 16 of 21 RNA-Puzzles revisited without experimental data or expert intervention, FARFAR2 recovers native-like structures more accurate than models submitted during the RNA-Puzzles trials. Remaining bottlenecks include conformational sampling for >80-nucleotide problems and scoring function limitations more generally. Supporting these conclusions, preregistered blind models for adenovirus VA-I RNA and five riboswitch complexes predicted native-like folds with 3- to 14 Å root-mean-square deviation accuracies. We present a FARFAR2 webserver and three large model archives (FARFAR2-Classics, FARFAR2-Motifs, and FARFAR2-Puzzles) to guide future applications and advances.
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Affiliation(s)
- Andrew Martin Watkins
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ramya Rangan
- Biophysics Program, Stanford University, Stanford, CA 94305, USA
| | - Rhiju Das
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA; Biophysics Program, Stanford University, Stanford, CA 94305, USA.
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21
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Novikov IB, Wilkins AD, Lichtarge O. An Evolutionary Trace method defines functionally important bases and sites common to RNA families. PLoS Comput Biol 2020; 16:e1007583. [PMID: 32208421 PMCID: PMC7092961 DOI: 10.1371/journal.pcbi.1007583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 11/27/2019] [Indexed: 11/18/2022] Open
Abstract
Functional non-coding (fnc)RNAs are nucleotide sequences of varied lengths, structures, and mechanisms that ubiquitously influence gene expression and translation, genome stability and dynamics, and human health and disease. Here, to shed light on their functional determinants, we seek to exploit the evolutionary record of variation and divergence read from sequence comparisons. The approach follows the phylogenetic Evolutionary Trace (ET) paradigm, first developed and extensively validated on proteins. We assigned a relative rank of importance to every base in a study of 1070 functional RNAs, including the ribosome, and observed evolutionary patterns strikingly similar to those seen in proteins, namely, (1) the top-ranked bases clustered in secondary and tertiary structures. (2) In turn, these clusters mapped functional regions for catalysis, binding proteins and drugs, post-transcriptional modification, and deleterious mutations. (3) Moreover, the quantitative quality of these clusters correlated with the identification of functional regions. (4) As a result of this correlation, smoother structural distributions of evolutionary important nucleotides improved functional site predictions. Thus, in practice, phylogenetic analysis can broadly identify functional determinants in RNA sequences and functional sites in RNA structures, and reveal details on the basis of RNA molecular functions. As example of application, we report several previously undocumented and potentially functional ET nucleotide clusters in the ribosome. This work is broadly relevant to studies of structure-function in ribonucleic acids. Additionally, this generalization of ET shows that evolutionary constraints among sequence, structure, and function are similar in structured RNA and proteins. RNA ET is currently available as part of the ET command-line package, and will be available as a web-server. Traditionally, RNA has been delegated to the role of an intermediate between DNA and proteins. However, we now recognize that RNAs are broadly functional beyond their role in translation, and that a number of diverse classes exist. Because functional, non-coding RNAs are prevalent in biology and impact human health, it is important to better understand their functional determinants. However, the classical solution to this problem, targeted mutagenesis, is time-consuming and scales poorly. We propose an alternative computational approach to this problem, the Evolutionary Trace method. Previously developed and validated for proteins, Evolutionary Trace examines evolutionary history of a molecule and predicts evolutionarily important residues in the sequence. We apply Evolutionary Trace to a set of diverse RNAs, and find that the evolutionarily important nucleotides cluster on the three-dimensional structure, and that these clusters closely overlap functional sites. We also find that the clustering property can be used to refine and improve predictions. These findings are in close agreement with our observations of Evolutionary Trace in proteins, and suggest that structured functional RNAs and proteins evolve under similar constraints. In practice, the approach is to be used by RNA researches seeking insight into their molecule of interest, and the Evolutionary Trace program, along with a working example, is available at https://github.com/LichtargeLab/RNA_ET_ms.
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Affiliation(s)
- Ilya B. Novikov
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Angela D. Wilkins
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Olivier Lichtarge
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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22
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Naghdi MR, Boutet E, Mucha C, Ouellet J, Perreault J. Single Mutation in Hammerhead Ribozyme Favors Cleavage Activity with Manganese over Magnesium. Noncoding RNA 2020; 6:E14. [PMID: 32245091 PMCID: PMC7151607 DOI: 10.3390/ncrna6010014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/16/2020] [Accepted: 03/18/2020] [Indexed: 12/11/2022] Open
Abstract
Hammerhead ribozymes are one of the most studied classes of ribozymes so far, from both the structural and biochemical point of views. The activity of most hammerhead ribozymes is cation-dependent. Mg2+ is one of the most abundant divalent cations in the cell and therefore plays a major role in cleavage activity for most hammerhead ribozymes. Besides Mg2+, cleavage can also occur in the presence of other cations such as Mn2+. The catalytic core of hammerhead ribozymes is highly conserved, which could contribute to a preference of hammerhead ribozymes toward certain cations. Here, we show a naturally occurring variation in the catalytic core of hammerhead ribozymes, A6C, that can favor one metallic ion, Mn2+, over several other cations.
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Affiliation(s)
- Mohammad Reza Naghdi
- Institut National de la Recherche Scientifique (INRS), Centre Armand Frappier Santé Biotechnologie, 531 boul. des Prairies, Laval, QB H7V 1B7, Canada; (M.R.N.); (E.B.); (C.M.)
| | - Emilie Boutet
- Institut National de la Recherche Scientifique (INRS), Centre Armand Frappier Santé Biotechnologie, 531 boul. des Prairies, Laval, QB H7V 1B7, Canada; (M.R.N.); (E.B.); (C.M.)
| | - Clarisse Mucha
- Institut National de la Recherche Scientifique (INRS), Centre Armand Frappier Santé Biotechnologie, 531 boul. des Prairies, Laval, QB H7V 1B7, Canada; (M.R.N.); (E.B.); (C.M.)
| | - Jonathan Ouellet
- Department of Chemistry and Physics, Monmouth University, 400 Cedar Avenue, West Long Branch, NJ 07764, USA;
| | - Jonathan Perreault
- Institut National de la Recherche Scientifique (INRS), Centre Armand Frappier Santé Biotechnologie, 531 boul. des Prairies, Laval, QB H7V 1B7, Canada; (M.R.N.); (E.B.); (C.M.)
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23
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Gaines CS, Piccirilli JA, York DM. The L-platform/L-scaffold framework: a blueprint for RNA-cleaving nucleic acid enzyme design. RNA (NEW YORK, N.Y.) 2020; 26:111-125. [PMID: 31776179 PMCID: PMC6961537 DOI: 10.1261/rna.071894.119] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 11/14/2019] [Indexed: 05/13/2023]
Abstract
We develop an L-platform/L-scaffold framework we hypothesize may serve as a blueprint to facilitate site-specific RNA-cleaving nucleic acid enzyme design. Building on the L-platform motif originally described by Suslov and coworkers, we identify new critical scaffolding elements required to anchor a conserved general base guanine ("L-anchor") and bind functionally important metal ions at the active site ("L-pocket"). Molecular simulations, together with a broad range of experimental structural and functional data, connect the L-platform/L-scaffold elements to necessary and sufficient conditions for catalytic activity. We demonstrate that the L-platform/L-scaffold framework is common to five of the nine currently known naturally occurring ribozyme classes (Twr, HPr, VSr, HHr, Psr), and intriguingly from a design perspective, the framework also appears in an artificially engineered DNAzyme (8-17dz). The flexibility of the L-platform/L-scaffold framework is illustrated on these systems, highlighting modularity and trends in the variety of known general acid moieties that are supported. These trends give rise to two distinct catalytic paradigms, building on the classifications proposed by Wilson and coworkers and named for the implicated general base and acid. The "G + A" paradigm (Twr, HPr, VSr) exclusively utilizes nucleobase residues for chemistry, and the "G + M + " paradigm (HHr, 8-17dz, Psr) involves structuring of the "L-pocket" metal ion binding site for recruitment of a divalent metal ion that plays an active role in the chemical steps of the reaction. Finally, the modularity of the L-platform/L-scaffold framework is illustrated in the VS ribozyme where the "L-pocket" assumes the functional role of the "L-anchor" element, highlighting a distinct mechanism, but one that is functionally linked with the hammerhead ribozyme.
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Affiliation(s)
- Colin S Gaines
- Laboratory for Biomolecular Simulation Research, Institute for Quantitative Biomedicine, and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Joseph A Piccirilli
- Department of Biochemistry and Molecular Biology and Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA
| | - Darrin M York
- Laboratory for Biomolecular Simulation Research, Institute for Quantitative Biomedicine, and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, USA
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24
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Confluence of theory and experiment reveals the catalytic mechanism of the Varkud satellite ribozyme. Nat Chem 2020; 12:193-201. [PMID: 31959957 PMCID: PMC7389185 DOI: 10.1038/s41557-019-0391-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 11/13/2019] [Indexed: 11/09/2022]
Abstract
The Varkud satellite ribozyme catalyses site-specific RNA cleavage and ligation, and serves as an important model system to understand RNA catalysis. Here, we combine stereospecific phosphorothioate substitution, precision nucleobase mutation and linear free-energy relationship measurements with molecular dynamics, molecular solvation theory and ab initio quantum mechanical/molecular mechanical free-energy simulations to gain insight into the catalysis. Through this confluence of theory and experiment, we unify the existing body of structural and functional data to unveil the catalytic mechanism in unprecedented detail, including the degree of proton transfer in the transition state. Further, we provide evidence for a critical Mg2+ in the active site that interacts with the scissile phosphate and anchors the general base guanine in position for nucleophile activation. This novel role for Mg2+ adds to the diversity of known catalytic RNA strategies and unifies functional features observed in the Varkud satellite, hairpin and hammerhead ribozyme classes.
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25
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Ma L, Kartik S, Liu B, Liu J. From general base to general acid catalysis in a sodium-specific DNAzyme by a guanine-to-adenine mutation. Nucleic Acids Res 2019; 47:8154-8162. [PMID: 31276580 PMCID: PMC6736077 DOI: 10.1093/nar/gkz578] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 06/20/2019] [Accepted: 06/26/2019] [Indexed: 02/07/2023] Open
Abstract
Recently, a few Na+-specific RNA-cleaving DNAzymes were reported, where nucleobases are likely to play critical roles in catalysis. The NaA43 and NaH1 DNAzymes share the same 16-nt Na+-binding motif, but differ in one or two nucleotides in a small catalytic loop. Nevertheless, they display an opposite pH-dependency, implicating distinct catalytic mechanisms. In this work, rational mutation studies locate a catalytic adenine residue, A22, in NaH1, while previous studies found a guanine (G23) to be important for the catalysis of NaA43. Mutation with pKa-perturbed analogs, such as 2-aminopurine (∼3.8), 2,6-diaminopurine (∼5.6) and hypoxanthine (∼8.7) affected the overall reaction rate. Therefore, we propose that the N1 position of G23 (pKa ∼6.6) in NaA43 functions as a general base, while that of A22 (pKa ∼6.3) in NaH1 as a general acid. Further experiments with base analogs and a phosphorothioate-modified substrate suggest that the exocyclic amine in A22 and both of the non-bridging oxygens at the scissile phosphate are important for catalysis for NaH1. This is an interesting example where single point mutations can change the mechanism of cleavage from general base to general acid, and it can also explain this Na+-dependent DNAzyme scaffold being sensitive to a broad range of metal ions and molecules.
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Affiliation(s)
- Lingzi Ma
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Sanjana Kartik
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Biwu Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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26
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Maurel MC, Leclerc F, Hervé G. Ribozyme Chemistry: To Be or Not To Be under High Pressure. Chem Rev 2019; 120:4898-4918. [DOI: 10.1021/acs.chemrev.9b00457] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marie-Christine Maurel
- Institut de Systématique, Evolution, Biodiversité (ISYEB), CNRS, Sorbonne Université, Muséum National d’Histoire Naturelle, EPHE, F-75005 Paris, France
| | - Fabrice Leclerc
- Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, Université Paris Sud, F-91198 Gif-sur-Yvette, France
| | - Guy Hervé
- Laboratoire BIOSIPE, Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Campus Pierre et Marie Curie, F-75005 Paris, France
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27
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Ekesan Ş, York DM. Dynamical ensemble of the active state and transition state mimic for the RNA-cleaving 8-17 DNAzyme in solution. Nucleic Acids Res 2019; 47:10282-10295. [PMID: 31511899 PMCID: PMC6821293 DOI: 10.1093/nar/gkz773] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/20/2019] [Accepted: 09/03/2019] [Indexed: 02/01/2023] Open
Abstract
We perform molecular dynamics simulations, based on recent crystallographic data, on the 8-17 DNAzyme at four states along the reaction pathway to determine the dynamical ensemble for the active state and transition state mimic in solution. A striking finding is the diverse roles played by Na+ and Pb2+ ions in the electrostatically strained active site that impact all four fundamental catalytic strategies, and share commonality with some features recently inferred for naturally occurring hammerhead and pistol ribozymes. The active site Pb2+ ion helps to stabilize in-line nucleophilic attack, provides direct electrostatic transition state stabilization, and facilitates leaving group departure. A conserved guanine residue is positioned to act as the general base, and is assisted by a bridging Na+ ion that tunes the pKa and facilitates in-line fitness. The present work provides insight into how DNA molecules are able to solve the RNA-cleavage problem, and establishes functional relationships between the mechanism of these engineered DNA enzymes with their naturally evolved RNA counterparts. This adds valuable information to our growing body of knowledge on general mechanisms of phosphoryl transfer reactions catalyzed by RNA, proteins and DNA.
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Affiliation(s)
- Şölen Ekesan
- Laboratory for Biomolecular Simulation Research, Institute for Quantitative Biomedicine, and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Darrin M York
- Laboratory for Biomolecular Simulation Research, Institute for Quantitative Biomedicine, and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
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28
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Kostenbader K, York DM. Molecular simulations of the pistol ribozyme: unifying the interpretation of experimental data and establishing functional links with the hammerhead ribozyme. RNA (NEW YORK, N.Y.) 2019; 25:1439-1456. [PMID: 31363004 PMCID: PMC6795133 DOI: 10.1261/rna.071944.119] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 07/11/2019] [Indexed: 05/27/2023]
Abstract
The pistol ribozyme (Psr) is among the most recently discovered RNA enzymes and has been the subject of experiments aimed at elucidating the mechanism. Recent biochemical studies have revealed exciting clues about catalytic interactions in the active site not apparent from available crystallographic data. The present work unifies the interpretation of the existing body of structural and functional data on Psr by providing a dynamical model for the catalytically active state in solution from molecular simulation. Our results suggest that a catalytic Mg2+ ion makes inner-sphere contact with G33:N7 and outer-sphere coordination to the pro-RP of the scissile phosphate, promoting electrostatic stabilization of the dianionic transition state and neutralization of the developing charge of the leaving group through a metal-coordinated water molecule that is made more acidic by a hydrogen bond donated from the 2'OH of P32. This model is consistent with experimental activity-pH and mutagenesis data, including sensitivity to G33(7cG) and phosphorothioate substitution/metal ion rescue. The model suggests several experimentally testable predictions, including the response of cleavage activity to mutations at G42 and P32 positions in the ribozyme, and thio substitutions of the substrate in the presence of different divalent metal ions. Further, the model identifies striking similarities of Psr to the hammerhead ribozyme (HHr), including similar global fold, organization of secondary structure around an active site three-way junction, catalytic metal ion binding mode, and guanine general base. However, the specific binding mode and role of the Mg2+ ion, as well as a conserved 2'-OH in the active site, are interrelated but subtly different between the ribozymes.
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Affiliation(s)
- Ken Kostenbader
- Laboratory for Biomolecular Simulation Research, Institute for Quantitative Biomedicine, and Department of Chemistry & Chemical Biology, Rutgers University, Piscataway, New Jersey 08854-8076, USA
| | - Darrin M York
- Laboratory for Biomolecular Simulation Research, Institute for Quantitative Biomedicine, and Department of Chemistry & Chemical Biology, Rutgers University, Piscataway, New Jersey 08854-8076, USA
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Maurel MC, Leclerc F, Vergne J, Zaccai G. RNA Back and Forth: Looking through Ribozyme and Viroid Motifs. Viruses 2019; 11:E283. [PMID: 30901893 PMCID: PMC6466107 DOI: 10.3390/v11030283] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 03/14/2019] [Accepted: 03/18/2019] [Indexed: 12/28/2022] Open
Abstract
Current cellular facts allow us to follow the link from chemical to biochemical metabolites, from the ancient to the modern world. In this context, the "RNA world" hypothesis proposes that early in the evolution of life, the ribozyme was responsible for the storage and transfer of genetic information and for the catalysis of biochemical reactions. Accordingly, the hammerhead ribozyme (HHR) and the hairpin ribozyme belong to a family of endonucleolytic RNAs performing self-cleavage that might occur during replication. Furthermore, regarding the widespread occurrence of HHRs in several genomes of modern organisms (from mammals to small parasites and elsewhere), these small ribozymes have been regarded as living fossils of a primitive RNA world. They fold into 3D structures that generally require long-range intramolecular interactions to adopt the catalytically active conformation under specific physicochemical conditions. By studying viroids as plausible remains of ancient RNA, we recently demonstrated that they replicate in non-specific hosts, emphasizing their adaptability to different environments, which enhanced their survival probability over the ages. All these results exemplify ubiquitous features of life. Those are the structural and functional versatility of small RNAs, ribozymes, and viroids, as well as their diversity and adaptability to various extreme conditions. All these traits must have originated in early life to generate novel RNA populations.
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Affiliation(s)
- Marie-Christine Maurel
- Sorbonne Université, Museum National d'Histoire Naturelle, CNRS MNHN UMR 7205, Institut de Systématique, Evolution, Biodiversité, ISYEB, F-75005 Paris, France.
| | - Fabrice Leclerc
- Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, Université Paris Sud, F-91198 Gif-sur-Yvette, France.
| | - Jacques Vergne
- Sorbonne Université, Museum National d'Histoire Naturelle, CNRS MNHN UMR 7205, Institut de Systématique, Evolution, Biodiversité, ISYEB, F-75005 Paris, France.
| | - Giuseppe Zaccai
- Institut de Biologie Structurale CNRS-CEA-UGA, F-380447 Grenoble, France, and Institut Laue Langevin, 71 Avenue des Martyrs, F-38042 Grenoble, France.
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30
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Ong AAL, Toh DFK, Patil KM, Meng Z, Yuan Z, Krishna MS, Devi G, Haruehanroengra P, Lu Y, Xia K, Okamura K, Sheng J, Chen G. General Recognition of U-G, U-A, and C-G Pairs by Double-Stranded RNA-Binding PNAs Incorporated with an Artificial Nucleobase. Biochemistry 2019; 58:1319-1331. [PMID: 30775913 DOI: 10.1021/acs.biochem.8b01313] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Chemically modified peptide nucleic acids (PNAs) show great promise in the recognition of RNA duplexes by major-groove PNA·RNA-RNA triplex formation. Triplex formation is favored for RNA duplexes with a purine tract within one of the RNA duplex strands, and is severely destabilized if the purine tract is interrupted by pyrimidine residues. Here, we report the synthesis of a PNA monomer incorporated with an artificial nucleobase S, followed by the binding studies of a series of S-modified PNAs. Our data suggest that an S residue incorporated into short 8-mer dsRNA-binding PNAs (dbPNAs) can recognize internal Watson-Crick C-G and U-A, and wobble U-G base pairs (but not G-C, A-U, and G-U pairs) in RNA duplexes. The short S-modified PNAs show no appreciable binding to DNA duplexes or single-stranded RNAs. Interestingly, replacement of the C residue in an S·C-G triple with a 5-methyl C results in the disruption of the triplex, probably due to a steric clash between S and 5-methyl C. Previously reported PNA E base shows recognition of U-A and A-U pairs, but not a U-G pair. Thus, S-modified dbPNAs may be uniquely useful for the general recognition of RNA U-G, U-A, and C-G pairs. Shortening the succinyl linker of our PNA S monomer by one carbon atom to have a malonyl linker causes a severe destabilization of triplex formation. Our experimental and modeling data indicate that part of the succinyl moiety in a PNA S monomer may serve to expand the S base forming stacking interactions with adjacent PNA bases.
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Affiliation(s)
- Alan Ann Lerk Ong
- NTU Institute for Health Technologies (HeathTech NTU), Interdisciplinary Graduate School , Nanyang Technological University , 50 Nanyang Drive , Singapore 637553.,Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , Singapore 637371
| | - Desiree-Faye Kaixin Toh
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , Singapore 637371
| | - Kiran M Patil
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , Singapore 637371
| | - Zhenyu Meng
- Division of Mathematical Sciences, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , Singapore 637371
| | - Zhen Yuan
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , Singapore 637371
| | - Manchugondanahalli S Krishna
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , Singapore 637371
| | - Gitali Devi
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , Singapore 637371
| | - Phensinee Haruehanroengra
- Department of Chemistry and The RNA Institute , University at Albany, State University of New York , 1400 Washington Avenue , Albany , New York 12222 , United States
| | - Yunpeng Lu
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , Singapore 637371
| | - Kelin Xia
- Division of Mathematical Sciences, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , Singapore 637371
| | - Katsutomo Okamura
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore , Singapore , 117604.,School of Biological Sciences , Nanyang Technological University , 60 Nanyang Drive , Singapore , 639798
| | - Jia Sheng
- Department of Chemistry and The RNA Institute , University at Albany, State University of New York , 1400 Washington Avenue , Albany , New York 12222 , United States
| | - Gang Chen
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , Singapore 637371
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31
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O'Rourke SM, Scott WG. Structural Simplicity and Mechanistic Complexity in the Hammerhead Ribozyme. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2018; 159:177-202. [PMID: 30340787 DOI: 10.1016/bs.pmbts.2018.07.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Natural or full-length hammerhead ribozymes are up to 1000-fold more active than their minimal counterparts that lack a complex tertiary interaction that pre-organizes and stabilizes the ribozyme active site, positioning RNA functional groups to facilitate acid-base catalysis. The recent discovery that a single tertiary contact (an AU Hoogsteen pair) between Stems I and II confers essentially all of the enhanced activity greatly simplifies our understanding of the structural requirements for hammerhead ribozyme activity. In contrast, the simplest mechanistic interpretations are challenged with the presentation of more complex alternatives. These alternatives are elucidated and critically analyzed in the context of several of the active hammerhead ribozyme structures now available.
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Affiliation(s)
- Sara M O'Rourke
- The Center for the Molecular Biology of RNA, University of California at Santa Cruz, Santa Cruz, CA, United States
| | - William G Scott
- The Center for the Molecular Biology of RNA, University of California at Santa Cruz, Santa Cruz, CA, United States.
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32
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Šponer J, Bussi G, Krepl M, Banáš P, Bottaro S, Cunha RA, Gil-Ley A, Pinamonti G, Poblete S, Jurečka P, Walter NG, Otyepka M. RNA Structural Dynamics As Captured by Molecular Simulations: A Comprehensive Overview. Chem Rev 2018; 118:4177-4338. [PMID: 29297679 PMCID: PMC5920944 DOI: 10.1021/acs.chemrev.7b00427] [Citation(s) in RCA: 336] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Indexed: 12/14/2022]
Abstract
With both catalytic and genetic functions, ribonucleic acid (RNA) is perhaps the most pluripotent chemical species in molecular biology, and its functions are intimately linked to its structure and dynamics. Computer simulations, and in particular atomistic molecular dynamics (MD), allow structural dynamics of biomolecular systems to be investigated with unprecedented temporal and spatial resolution. We here provide a comprehensive overview of the fast-developing field of MD simulations of RNA molecules. We begin with an in-depth, evaluatory coverage of the most fundamental methodological challenges that set the basis for the future development of the field, in particular, the current developments and inherent physical limitations of the atomistic force fields and the recent advances in a broad spectrum of enhanced sampling methods. We also survey the closely related field of coarse-grained modeling of RNA systems. After dealing with the methodological aspects, we provide an exhaustive overview of the available RNA simulation literature, ranging from studies of the smallest RNA oligonucleotides to investigations of the entire ribosome. Our review encompasses tetranucleotides, tetraloops, a number of small RNA motifs, A-helix RNA, kissing-loop complexes, the TAR RNA element, the decoding center and other important regions of the ribosome, as well as assorted others systems. Extended sections are devoted to RNA-ion interactions, ribozymes, riboswitches, and protein/RNA complexes. Our overview is written for as broad of an audience as possible, aiming to provide a much-needed interdisciplinary bridge between computation and experiment, together with a perspective on the future of the field.
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Affiliation(s)
- Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences , Kralovopolska 135 , Brno 612 65 , Czech Republic
| | - Giovanni Bussi
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Miroslav Krepl
- Institute of Biophysics of the Czech Academy of Sciences , Kralovopolska 135 , Brno 612 65 , Czech Republic
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
| | - Pavel Banáš
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
| | - Sandro Bottaro
- Structural Biology and NMR Laboratory, Department of Biology , University of Copenhagen , Copenhagen 2200 , Denmark
| | - Richard A Cunha
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Alejandro Gil-Ley
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Giovanni Pinamonti
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Simón Poblete
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Petr Jurečka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
| | - Nils G Walter
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
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33
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Seith DD, Bingaman JL, Veenis AJ, Button AC, Bevilacqua PC. Elucidation of Catalytic Strategies of Small Nucleolytic Ribozymes From Comparative Analysis of Active Sites. ACS Catal 2018; 8:314-327. [PMID: 32547833 PMCID: PMC7296830 DOI: 10.1021/acscatal.7b02976] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A number of small, self-cleaving ribozyme classes have been identified including the hammerhead, hairpin, hepatitis delta virus (HDV), Varkud satellite (VS), glmS, twister, hatchet, pistol, and twister sister ribozymes. Within the active sites of these ribozymes, myriad functional groups contribute to catalysis. There has been extensive structure-function analysis of individual ribozymes, but the extent to which catalytic devices are shared across different ribozyme classes is unclear. As such, emergent catalytic principles for ribozymes may await discovery. Identification of conserved catalytic devices can deepen our understanding of RNA catalysis specifically and of enzymic catalysis generally. To probe similarities and differences amongst ribozyme classes, active sites from more than 80 high-resolution crystal structures of self-cleaving ribozymes were compared computationally. We identify commonalities amongst ribozyme classes pertaining to four classic catalytic devices: deprotonation of the 2'OH nucleophile (γ), neutralization of the non-bridging oxygens of the scissile phosphate (β), neutralization of the O5' leaving group (δ), and in-line nucleophilic attack (α). In addition, we uncover conservation of two catalytic devices, each of which centers on the activation of the 2'OH nucleophile by a guanine: one to acidify the 2'OH by hydrogen bond donation to it (γ') and one to acidify the 2'OH by releasing it from non-productive interactions by competitive hydrogen bonding (γ''). Our findings reveal that the amidine functionalities of G, A, and C are especially important for these strategies, and help explain absence of U at ribozyme active sites. The identified γ' and γ'' catalytic strategies help unify the catalytic strategies shared amongst catalytic RNAs and may be important for large ribozymes, as well as protein enzymes that act on nucleic acids.
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Affiliation(s)
- Daniel D. Seith
- Department of Chemistry and Center for RNA Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
- These two authors contributed equally to this work
| | - Jamie L. Bingaman
- Department of Chemistry and Center for RNA Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
- These two authors contributed equally to this work
| | - Andrew J. Veenis
- Department of Chemistry and Center for RNA Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Aileen C. Button
- Department of Chemistry and Center for RNA Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
- Department of Biochemistry, The University of Vermont, Burlington, Vermont 05405
| | - Philip C. Bevilacqua
- Department of Chemistry and Center for RNA Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
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34
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Liu X, Chen Y, Fierke CA. Inner-Sphere Coordination of Divalent Metal Ion with Nucleobase in Catalytic RNA. J Am Chem Soc 2017; 139:17457-17463. [PMID: 29116782 PMCID: PMC6020041 DOI: 10.1021/jacs.7b08755] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Identification of the function of metal ions and the RNA moieties, particularly nucleobases, that bind metal ions is important in RNA catalysis. Here we combine single-atom and abasic substitutions to probe functions of conserved nucleobases in ribonuclease P (RNase P). Structural and biophysical studies of bacterial RNase P propose direct coordination of metal ions by the nucleobases of conserved uridine and guanosine in helix P4 of the RNA subunit (P RNA). To biochemically probe the function of metal ion interactions, we substituted the universally conserved bulged uridine (U51) in the P4 helix of circularly permuted Bacillus subtilis P RNA with 4-thiouridine, 4-deoxyuridine, and abasic modifications and G378/379 with 2-aminopurine, N7-deazaguanosine, and 6-thioguanosine. The functional group modifications of U51 decrease RNase P-catalyzed phosphodiester bond cleavage 16- to 23-fold, as measured by the single-turnover cleavage rate constant. The activity of the 4-thiouridine RNase P is partially rescued by addition of Cd(II) or Mn(II) ions. This is the first time a metal-rescue experiment provides evidence for inner-sphere divalent metal ion coordination with a nucleobase. Modifications of G379 modestly decrease the cleavage activity of RNase P, suggesting outer-sphere coordination of O6 on G379 to a metal ion. These data provide biochemical evidence for catalytically important interactions of the P4 helix of P RNA with metal ions, demonstrating that the bulged uridine coordinates at least one catalytic metal ion through an inner-sphere interaction. The combination of single-atom and abasic nucleotide substitutions provides a powerful strategy to probe functions of conserved nucleobases in large RNAs.
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Affiliation(s)
- Xin Liu
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Yu Chen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Carol A. Fierke
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
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35
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Ren A, Micura R, Patel DJ. Structure-based mechanistic insights into catalysis by small self-cleaving ribozymes. Curr Opin Chem Biol 2017; 41:71-83. [PMID: 29107885 PMCID: PMC7955703 DOI: 10.1016/j.cbpa.2017.09.017] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 09/22/2017] [Accepted: 09/29/2017] [Indexed: 01/01/2023]
Abstract
Small self-cleaving ribozymes are widely distributed in nature and are essential for rolling-circle-based replication of satellite and pathogenic RNAs. Earlier structure-function studies on the hammerhead, hairpin, glmS, hepatitis delta virus and Varkud satellite ribozymes have provided insights into their overall architecture, their catalytic active site organization, and the role of nearby nucleobases and hydrated divalent cations in facilitating general acid-base and electrostatic-mediated catalysis. This review focuses on recent structure-function research on active site alignments and catalytic mechanisms of the Rzb hammerhead ribozyme, as well as newly-identified pistol, twister and twister-sister ribozymes. In contrast to an agreed upon mechanistic understanding of self-cleavage by Rzb hammerhead and pistol ribozymes, there exists a divergence of views as to the cleavage site alignments and catalytic mechanisms adopted by twister and twister-sister ribozymes. One approach to resolving this conundrum would be to extend the structural studies from currently available pre-catalytic conformations to their transition state mimic vanadate counterparts for both ribozymes.
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Affiliation(s)
- Aiming Ren
- Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Ronald Micura
- Institute of Organic Chemistry, Leopold Franzens University, Innsbruck A6020, Austria
| | - Dinshaw J Patel
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
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36
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Mlýnský V, Kührová P, Jurečka P, Šponer J, Otyepka M, Banáš P. Mapping the Chemical Space of the RNA Cleavage and Its Implications for Ribozyme Catalysis. J Phys Chem B 2017; 121:10828-10840. [DOI: 10.1021/acs.jpcb.7b09129] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vojtěch Mlýnský
- Regional Centre
of Advanced Technologies and Materials, Department of Physical Chemistry,
Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46 Olomouc, Czech Republic
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), via
Bonomea 265, 34136 Trieste, Italy
| | - Petra Kührová
- Regional Centre
of Advanced Technologies and Materials, Department of Physical Chemistry,
Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46 Olomouc, Czech Republic
| | - Petr Jurečka
- Regional Centre
of Advanced Technologies and Materials, Department of Physical Chemistry,
Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46 Olomouc, Czech Republic
| | - Jiří Šponer
- Regional Centre
of Advanced Technologies and Materials, Department of Physical Chemistry,
Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46 Olomouc, Czech Republic
- Institute of Biophysics of the Czech Academy of Sciences, Kralovopolská 135, 612 65 Brno, Czech Republic
| | - Michal Otyepka
- Regional Centre
of Advanced Technologies and Materials, Department of Physical Chemistry,
Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46 Olomouc, Czech Republic
| | - Pavel Banáš
- Regional Centre
of Advanced Technologies and Materials, Department of Physical Chemistry,
Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46 Olomouc, Czech Republic
- Institute of Biophysics of the Czech Academy of Sciences, Kralovopolská 135, 612 65 Brno, Czech Republic
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37
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Zheng L, Mairhofer E, Teplova M, Zhang Y, Ma J, Patel DJ, Micura R, Ren A. Structure-based insights into self-cleavage by a four-way junctional twister-sister ribozyme. Nat Commun 2017; 8:1180. [PMID: 29081514 PMCID: PMC5660989 DOI: 10.1038/s41467-017-01276-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 09/01/2017] [Indexed: 11/13/2022] Open
Abstract
Here we report on the crystal structure and cleavage assays of a four-way junctional twister-sister self-cleaving ribozyme. Notably, 11 conserved spatially separated loop nucleotides are brought into close proximity at the ribozyme core through long-range interactions mediated by hydrated Mg2+ cations. The C62–A63 step at the cleavage site adopts a splayed-apart orientation, with flexible C62 directed outwards, whereas A63 is directed inwards and anchored by stacking and hydrogen-bonding interactions. Structure-guided studies of key base, sugar, and phosphate mutations in the twister-sister ribozyme, suggest contributions to the cleavage chemistry from interactions between a guanine at the active site and the non-bridging oxygen of the scissile phosphate, a feature found previously also for the related twister ribozyme. Our four-way junctional pre-catalytic structure differs significantly in the alignment at the cleavage step (splayed-apart vs. base-stacked) and surrounding residues and hydrated Mg2+ ions relative to a reported three-way junctional pre-catalytic structure of the twister-sister ribozyme. Twister-sister is a self-cleaving ribozyme. Here, the authors report the 2.0 Å crystal structure of the four-way junctional twister-sister ribozyme in the pre-catalytic state and discuss mechanistic implications based on their mutagenesis experiments and comparisons with other ribozyme structures.
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Affiliation(s)
- Luqian Zheng
- Life Sciences Institute, Zhejiang University, 310058, Hangzhou, China
| | - Elisabeth Mairhofer
- Institute of Organic Chemistry, Leopold Franzens University, A6020, Innsbruck, Austria
| | - Marianna Teplova
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, 10065, USA
| | - Ye Zhang
- Life Sciences Institute, Zhejiang University, 310058, Hangzhou, China
| | - Jinbiao Ma
- Department of Biochemistry, State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, 200438, Shanghai, China.,Collaborative Innovation Centre of Genetics and Development, Fudan University, 200438, Shanghai, China
| | - Dinshaw J Patel
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, 10065, USA
| | - Ronald Micura
- Institute of Organic Chemistry, Leopold Franzens University, A6020, Innsbruck, Austria.
| | - Aiming Ren
- Life Sciences Institute, Zhejiang University, 310058, Hangzhou, China. .,Collaborative Innovation Centre of Genetics and Development, Fudan University, 200438, Shanghai, China.
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38
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Mao J, DeSantis C, Bong D. Small Molecule Recognition Triggers Secondary and Tertiary Interactions in DNA Folding and Hammerhead Ribozyme Catalysis. J Am Chem Soc 2017; 139:9815-9818. [PMID: 28691825 DOI: 10.1021/jacs.7b05448] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We have identified tris(2-aminoethyl)amine (tren)-derived scaffolds with two (t2M) or four (t4M) melamine rings that can target oligo T/U domains in DNA/RNA. Unstructured T-rich DNAs cooperatively fold with the tren derivatives to form hairpin-like structures. Both t2M and t4M act as functional switches in a family of hammerhead ribozymes deactivated by stem or loop replacement with a U-rich sequence. Catalysis of bond scission in these hammerhead ribozymes could be restored by putative t2M/t4M refolding of stem secondary structure or tertiary bridging interactions between loop and stem. The simplicity of the t2M/t4M binding site enables programming of allostery in RNAs, recoding oligo-U domains as potential sites for secondary structure or tertiary contact. In combination with a facile and general method for installation of the t2M motif on primary amines, the method described herein streamlines design of synthetic allosteric riboswitches and small molecule-nucleic acid complexes.
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Affiliation(s)
- Jie Mao
- Department of Chemistry and Biochemistry, The Ohio State University , 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Chris DeSantis
- Department of Chemistry and Biochemistry, The Ohio State University , 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Dennis Bong
- Department of Chemistry and Biochemistry, The Ohio State University , 100 West 18th Avenue, Columbus, Ohio 43210, United States
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39
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Chen H, Giese TJ, Golden BL, York DM. Divalent Metal Ion Activation of a Guanine General Base in the Hammerhead Ribozyme: Insights from Molecular Simulations. Biochemistry 2017; 56:2985-2994. [PMID: 28530384 DOI: 10.1021/acs.biochem.6b01192] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The hammerhead ribozyme is a well-studied nucleolytic ribozyme that catalyzes the self-cleavage of the RNA phosphodiester backbone. Despite experimental and theoretical efforts, key questions remain about details of the mechanism with regard to the activation of the nucleophile by the putative general base guanine (G12). Straightforward interpretation of the measured activity-pH data implies the pKa value of the N1 position in the G12 nucleobase is significantly shifted by the ribozyme environment. Recent crystallographic and biochemical work has identified pH-dependent divalent metal ion binding at the N7/O6 position of G12, leading to the hypothesis that this binding mode could induce a pKa shift of G12 toward neutrality. We present computational results that support this hypothesis and provide a model that unifies the interpretation of available structural and biochemical data and paints a detailed mechanistic picture of the general base step of the reaction. Experimentally testable predictions are made for mutational and rescue effects on G12, which will give further insights into the catalytic mechanism. These results contribute to our growing knowledge of the potential roles of divalent metal ions in RNA catalysis.
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Affiliation(s)
- Haoyuan Chen
- Laboratory for Biomolecular Simulation Research, Center for Integrative Proteomics Research, and Department of Chemistry & Chemical Biology, Rutgers University , 174 Frelinghuysen Road, Piscataway, New Jersey 08854-8076, United States
| | - Timothy J Giese
- Laboratory for Biomolecular Simulation Research, Center for Integrative Proteomics Research, and Department of Chemistry & Chemical Biology, Rutgers University , 174 Frelinghuysen Road, Piscataway, New Jersey 08854-8076, United States
| | - Barbara L Golden
- Department of Biochemistry, Purdue University , West Lafayette, Indiana 47907, United States
| | - Darrin M York
- Laboratory for Biomolecular Simulation Research, Center for Integrative Proteomics Research, and Department of Chemistry & Chemical Biology, Rutgers University , 174 Frelinghuysen Road, Piscataway, New Jersey 08854-8076, United States
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40
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Frankel EA, Strulson CA, Keating CD, Bevilacqua PC. Cooperative Interactions in the Hammerhead Ribozyme Drive pK a Shifting of G12 and Its Stacked Base C17. Biochemistry 2017; 56:2537-2548. [PMID: 28485924 DOI: 10.1021/acs.biochem.7b00174] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
General acid-base catalysis is a key mechanistic strategy in protein and RNA enzymes. Ribozymes use hydrated metal ions, nucleobases, and organic cofactors to carry this out. In most small ribozymes, a guanosine is positioned to participate in proton transfer with the nucleophilic 2'-OH. The unshifted pKa values for nucleobases and solvated metal ions are far from neutrality, however, and thus nonideal for general acid-base catalysis. Herein, evidence is provided for cooperative interaction in the hammerhead ribozyme among the guanine that interacts with the nucleophilic 2'-OH, G12, the -1 nucleobase C17, and Mg2+ ions. We introduce global fitting for analyzing ribozyme rate-pH data parametric in Mg2+ concentration and benchmark this method on data from the hepatitis delta virus ribozyme. We then apply global fitting to new rate-pH data for the hammerhead ribozyme using a minimal three-dimensional, four-channel cooperative model. The value for the pKa of G12 that we obtain is channel-dependent and varies from 8.1 to 9.9, shifting closest toward neutrality in the presence of two cationic species: C17H+ and a Mg2+ ion. The value for the pKa of the -1 nucleotide, C17, is increased a remarkable 3.5-5 pKa units toward neutrality. Shifting of the pKa of C17 appears to be driven by an electrostatic sandwich of C17 between carbonyl groups of the 5'-neighboring U and of G12 and involves cation-π interactions. Rate-pH profiles reveal that the major reactive channel under biological Mg2+ and pH involves a cationic C17 rather than a second metal ion. Substitution of a cationic base for a metal underscores the versatility of RNA.
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Affiliation(s)
- Erica A Frankel
- Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States.,Center for RNA Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Christopher A Strulson
- Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States.,Center for RNA Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Christine D Keating
- Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Philip C Bevilacqua
- Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States.,Center for RNA Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States.,Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
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41
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Structural and Biochemical Properties of Novel Self-Cleaving Ribozymes. Molecules 2017; 22:molecules22040678. [PMID: 28441772 PMCID: PMC6154101 DOI: 10.3390/molecules22040678] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 04/07/2017] [Accepted: 04/13/2017] [Indexed: 01/20/2023] Open
Abstract
Fourteen well-defined ribozyme classes have been identified to date, among which nine are site-specific self-cleaving ribozymes. Very recently, small self-cleaving ribozymes have attracted renewed interest in their structure, biochemistry, and biological function since the discovery, during the last three years, of four novel ribozymes, termed twister, twister sister, pistol, and hatchet. In this review, we mainly address the structure, biochemistry, and catalytic mechanism of the novel ribozymes. They are characterized by distinct active site architectures and divergent, but similar, biochemical properties. The cleavage activities of the ribozymes are highly dependent upon divalent cations, pH, and base-specific mutations, which can cause changes in the nucleotide arrangement and/or electrostatic potential around the cleavage site. It is most likely that a guanine and adenine in close proximity of the cleavage site are involved in general acid-base catalysis. In addition, metal ions appear to play a structural rather than catalytic role although some of their crystal structures have shown a direct metal ion coordination to a non-bridging phosphate oxygen at the cleavage site. Collectively, the structural and biochemical data of the four newest ribozymes could contribute to advance our mechanistic understanding of how self-cleaving ribozymes accomplish their efficient site-specific RNA cleavages.
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42
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Poudyal RR, Benslimane M, Lokugamage MP, Callaway MK, Staller S, Burke DH. Selective Inactivation of Functional RNAs by Ribozyme-Catalyzed Covalent Modification. ACS Synth Biol 2017; 6:528-534. [PMID: 28139121 DOI: 10.1021/acssynbio.6b00222] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The diverse functions of RNA provide numerous opportunities for programming biological circuits. We describe a new strategy that uses ribozyme K28min to covalently tag a specific nucleobase within an RNA or DNA target strand to regulate and selectively inactivate those nucleic acids. K28min variants with appropriately reprogrammed internal guide sequences efficiently tagged multiple sites from an mRNA and from aptamer and ribozyme targets. Upon covalent modification by the corresponding K28min variant, an ATP-binding aptamer lost all affinity for ATP, and the fluorogenic Mango aptamer lost its ability to activate fluorescence of its dye ligand. Modifying a hammerhead ribozyme near the catalytic core led to loss of almost all of its substrate-cleaving activity, but modifying the same hammerhead ribozyme within a tertiary stabilizing element that reduces magnesium dependence only impaired substrate cleavage at low magnesium concentration. Thus, ribozyme-mediated covalent modification can be used both to selectively inactivate and to fine-tune the activities of targeted functional RNAs, analogous to the effects of post-translational modifications of proteins. Ribozyme-catalyzed covalent modification could therefore be developed to regulate nucleic acids components of synthetic and natural circuits.
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Affiliation(s)
- Raghav R. Poudyal
- Department of Biochemistry, ‡Genetics Area Program, §Department of Biological
Engineering, ∥Department of Molecular
Microbiology and Immunology, and ⊥Bond Life Sciences Center, University of Missouri Columbia, Coumbia, Missouri, 65211, United States
| | - Malak Benslimane
- Department of Biochemistry, ‡Genetics Area Program, §Department of Biological
Engineering, ∥Department of Molecular
Microbiology and Immunology, and ⊥Bond Life Sciences Center, University of Missouri Columbia, Coumbia, Missouri, 65211, United States
| | - Melissa P. Lokugamage
- Department of Biochemistry, ‡Genetics Area Program, §Department of Biological
Engineering, ∥Department of Molecular
Microbiology and Immunology, and ⊥Bond Life Sciences Center, University of Missouri Columbia, Coumbia, Missouri, 65211, United States
| | - Mackenzie K. Callaway
- Department of Biochemistry, ‡Genetics Area Program, §Department of Biological
Engineering, ∥Department of Molecular
Microbiology and Immunology, and ⊥Bond Life Sciences Center, University of Missouri Columbia, Coumbia, Missouri, 65211, United States
| | - Seth Staller
- Department of Biochemistry, ‡Genetics Area Program, §Department of Biological
Engineering, ∥Department of Molecular
Microbiology and Immunology, and ⊥Bond Life Sciences Center, University of Missouri Columbia, Coumbia, Missouri, 65211, United States
| | - Donald H. Burke
- Department of Biochemistry, ‡Genetics Area Program, §Department of Biological
Engineering, ∥Department of Molecular
Microbiology and Immunology, and ⊥Bond Life Sciences Center, University of Missouri Columbia, Coumbia, Missouri, 65211, United States
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43
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Leonarski F, D'Ascenzo L, Auffinger P. Mg2+ ions: do they bind to nucleobase nitrogens? Nucleic Acids Res 2017; 45:987-1004. [PMID: 27923930 PMCID: PMC5314772 DOI: 10.1093/nar/gkw1175] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Revised: 11/10/2016] [Accepted: 11/14/2016] [Indexed: 01/28/2023] Open
Abstract
Given the many roles proposed for Mg2+ in nucleic acids, it is essential to accurately determine their binding modes. Here, we surveyed the PDB to classify Mg2+ inner-sphere binding patterns to nucleobase imine N1/N3/N7 atoms. Among those, purine N7 atoms are considered to be the best nucleobase binding sites for divalent metals. Further, Mg2+ coordination to N7 has been implied in several ribozyme catalytic mechanisms. We report that Mg2+ assigned near imine nitrogens derive mostly from poor interpretations of electron density patterns and are most often misidentified Na+, K+, NH4+ ions, water molecules or spurious density peaks. Consequently, apart from few documented exceptions, Mg2+ ions do not bind to N7 atoms. Without much of a surprise, Mn2+, Zn2+ and Cd2+, which have a higher affinity for nitrogens, may contact N7 atoms when present in crystallization buffers. In this respect, we describe for the first time a potential Zn2+ ribosomal binding site involving two purine N7 atoms. Further, we provide a set of guidelines to help in the assignment of Mg2+ in crystallographic, cryo-EM, NMR and model building practices and discuss implications of our findings related to ion substitution experiments.
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Affiliation(s)
- Filip Leonarski
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000 Strasbourg, France
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Luigi D'Ascenzo
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000 Strasbourg, France
| | - Pascal Auffinger
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000 Strasbourg, France
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44
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Gebetsberger J, Micura R. Unwinding the twister ribozyme: from structure to mechanism. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 8. [PMID: 27863022 PMCID: PMC5408937 DOI: 10.1002/wrna.1402] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 09/12/2016] [Accepted: 10/10/2016] [Indexed: 11/12/2022]
Abstract
The twister ribozyme motif has been identified by bioinformatic means very recently. Currently, four crystal structures with ordered active sites together with a series of chemical and biochemical data provide insights into how this RNA accomplishes its efficient self‐cleavage. Of particular interest for a mechanistic proposal are structural distinctions observed in the active sites that concern the conformation of the U‐A cleavage site dinucleotide (in‐line alignment of the attacking 2′‐O nucleophile to the to‐be‐cleaved P—O5′ bond versus suboptimal alignments) as well as the presence/absence of Mg2+ ions at the scissile phosphate. All structures support the notion that an active site guanine and the conserved adenine at the cleavage site are important contributors to cleavage chemistry, likely being involved in general acid base catalysis. Evidence for innersphere coordination of a Mg2+ ion to the pro‐S nonbridging oxygen of the scissile phosphate stems from two of the four crystal structures. Together with the finding of thio/rescue effects for phosphorothioate substrates, this suggests the participation of divalent ions in the overall catalytic strategy employed by twister ribozymes. In this context, it is notable that twister retains wild‐type activity when the phylogenetically conserved stem P1 is deleted, able to cleave a single nucleotide only. WIREs RNA 2017, 8:e1402. doi: 10.1002/wrna.1402 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Jennifer Gebetsberger
- Institute of Organic Chemistry, Leopold-Franzens University and Center of Molecular Biosciences Innsbruck CMBI, Innsbruck, Austria
| | - Ronald Micura
- Institute of Organic Chemistry, Leopold-Franzens University and Center of Molecular Biosciences Innsbruck CMBI, Innsbruck, Austria
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45
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Ochieng PO, White NA, Feig M, Hoogstraten CG. Intrinsic Base-Pair Rearrangement in the Hairpin Ribozyme Directs RNA Conformational Sampling and Tertiary Interface Formation. J Phys Chem B 2016; 120:10885-10898. [PMID: 27701852 DOI: 10.1021/acs.jpcb.6b05606] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Dynamic fluctuations in RNA structure enable conformational changes that are required for catalysis and recognition. In the hairpin ribozyme, the catalytically active structure is formed as an intricate tertiary interface between two RNA internal loops. Substantial alterations in the structure of each loop are observed upon interface formation, or docking. The very slow on-rate for this relatively tight interaction has led us to hypothesize a double conformational capture mechanism for RNA-RNA recognition. We used extensive molecular dynamics simulations to assess conformational sampling in the undocked form of the loop domain containing the scissile phosphate (loop A). We observed several major accessible conformations with distinctive patterns of hydrogen bonding and base stacking interactions in the active-site internal loop. Several important conformational features characteristic of the docked state were observed in well-populated substates, consistent with the kinetic sampling of docking-competent states by isolated loop A. Our observations suggest a hybrid or multistage binding mechanism, in which initial conformational selection of a docking-competent state is followed by induced-fit adjustment to an in-line, chemically reactive state only after formation of the initial complex with loop B.
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Affiliation(s)
- Patrick O Ochieng
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Neil A White
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Michael Feig
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Charles G Hoogstraten
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
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46
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Leonarski F, D’Ascenzo L, Auffinger P. Binding of metals to purine N7 nitrogen atoms and implications for nucleic acids: A CSD survey. Inorganica Chim Acta 2016. [DOI: 10.1016/j.ica.2016.04.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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47
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Ren A, Vušurović N, Gebetsberger J, Gao P, Juen M, Kreutz C, Micura R, Patel DJ. Pistol ribozyme adopts a pseudoknot fold facilitating site-specific in-line cleavage. Nat Chem Biol 2016; 12:702-8. [PMID: 27398999 PMCID: PMC4990474 DOI: 10.1038/nchembio.2125] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 06/08/2016] [Indexed: 12/20/2022]
Abstract
The field of small self-cleaving nucleolytic ribozymes has been invigorated by the recent discovery of the twister, twister-sister, pistol and hatchet ribozymes. We report the crystal structure of a pistol ribozyme termed env25, which adopts a compact tertiary architecture stabilized by an embedded pseudoknot fold. The G-U cleavage site adopts a splayed-apart conformation with in-line alignment of the modeled 2'-O of G for attack on the adjacent to-be-cleaved P-O5' bond. Highly conserved residues G40 (N1 position) and A32 (N3 and 2'-OH positions) are aligned to act as a general base and a general acid, respectively, to accelerate cleavage chemistry, with their roles confirmed by cleavage assays on variants, and an increased pKa of 4.7 for A32. Our structure of the pistol ribozyme defined how the overall and local topologies dictate the in-line alignment at the G-U cleavage site, with cleavage assays on variants revealing key residues that participate in acid-base-catalyzed cleavage chemistry.
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Affiliation(s)
- Aiming Ren
- Life Sciences Institute, Zhejiang University, Hangzhou, China
- Structural Biology Program, Memorial Sloan-Kettering Cancer, New York, New York, USA
| | - Nikola Vušurović
- Institute of Organic Chemistry, Leopold Franzens University, Innsbruck, Austria
- Center of Molecular Biosciences (CMBI), Innsbruck, Austria
| | - Jennifer Gebetsberger
- Institute of Organic Chemistry, Leopold Franzens University, Innsbruck, Austria
- Center of Molecular Biosciences (CMBI), Innsbruck, Austria
| | - Pu Gao
- Structural Biology Program, Memorial Sloan-Kettering Cancer, New York, New York, USA
| | - Michael Juen
- Institute of Organic Chemistry, Leopold Franzens University, Innsbruck, Austria
- Center of Molecular Biosciences (CMBI), Innsbruck, Austria
| | - Christoph Kreutz
- Institute of Organic Chemistry, Leopold Franzens University, Innsbruck, Austria
- Center of Molecular Biosciences (CMBI), Innsbruck, Austria
| | - Ronald Micura
- Institute of Organic Chemistry, Leopold Franzens University, Innsbruck, Austria
- Center of Molecular Biosciences (CMBI), Innsbruck, Austria
| | - Dinshaw J Patel
- Structural Biology Program, Memorial Sloan-Kettering Cancer, New York, New York, USA
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48
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Leclerc F, Zaccai G, Vergne J, Řìhovà M, Martel A, Maurel MC. Self-assembly Controls Self-cleavage of HHR from ASBVd (-): a Combined SANS and Modeling Study. Sci Rep 2016; 6:30287. [PMID: 27456224 PMCID: PMC4960562 DOI: 10.1038/srep30287] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 06/29/2016] [Indexed: 01/16/2023] Open
Abstract
In the Avocado Sunblotch Viroid (ASBVd: 249-nt) from the Avsunviroidae family, a symmetric rolling-circle replication operates through an autocatalytic mechanism mediated by hammerhead ribozymes (HHR) embedded in both polarity strands. The concatenated multimeric ASBVd (+) and ASBVd (-) RNAs thus generated are processed by cleavage to unit-length where ASBVd (-) self-cleaves with more efficiency. Absolute scale small angle neutron scattering (SANS) revealed a temperature-dependent dimer association in both ASBVd (-) and its derived 79-nt HHR (-). A joint thermodynamic analysis of SANS and catalytic data indicates the rate-determining step corresponds to the dimer/monomer transition. 2D and 3D models of monomeric and dimeric HHR (-) suggest that the inter-molecular contacts stabilizing the dimer (between HI and HII domains) compete with the intra-molecular ones stabilizing the active conformation of the full-length HHR required for an efficient self-cleavage. Similar competing intra- and inter-molecular contacts are proposed in ASBVd (-) though with a remoter region from an extension of the HI domain.
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Affiliation(s)
- Fabrice Leclerc
- Institute for Integrative Biology of the Cell (I2BC), Dept. of Genome Biology, CEA, CNRS, Université Paris Sud, Gif-sur-Yvette, F-91198, France
| | - Giuseppe Zaccai
- Institut Laue Langevin, Grenoble, F-38042, France.,Institut de Biologie Structurale (IBS), CNRS, Grenoble, F-38044, France.,IBS, CEA, Grenoble, F-38044, France.,IBS, Univ Grenoble Alpes, Grenoble, F-38044, France
| | - Jacques Vergne
- Institut de Systématique, Evolution, Biodiversité ISyEB - UMR 7205 - CNRS, MNHN, UPMC, EPHE, UPMC, Sorbonne Universités, 57 rue Cuvier, CP 50 Paris, F-75005, France
| | - Martina Řìhovà
- Institut de Systématique, Evolution, Biodiversité ISyEB - UMR 7205 - CNRS, MNHN, UPMC, EPHE, UPMC, Sorbonne Universités, 57 rue Cuvier, CP 50 Paris, F-75005, France.,Institute of Physics, Charles University, Faculty of Mathematics and Physics, Prague 2, CZ-121 16, Czech Republic
| | - Anne Martel
- Institut Laue Langevin, Grenoble, F-38042, France
| | - Marie-Christine Maurel
- Institut de Systématique, Evolution, Biodiversité ISyEB - UMR 7205 - CNRS, MNHN, UPMC, EPHE, UPMC, Sorbonne Universités, 57 rue Cuvier, CP 50 Paris, F-75005, France
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49
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Mir A, Golden BL. Two Active Site Divalent Ions in the Crystal Structure of the Hammerhead Ribozyme Bound to a Transition State Analogue. Biochemistry 2016; 55:633-6. [PMID: 26551631 DOI: 10.1021/acs.biochem.5b01139] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The crystal structure of the hammerhead ribozyme bound to the pentavalent transition state analogue vanadate reveals significant rearrangements relative to the previously determined structures. The active site contracts, bringing G10.1 closer to the cleavage site and repositioning a divalent metal ion such that it could, ultimately, interact directly with the scissile phosphate. This ion could also position a water molecule to serve as a general acid in the cleavage reaction. A second divalent ion is observed coordinated to O6 of G12. This metal ion is well-placed to help tune the pKA of G12. On the basis of this crystal structure as well as a wealth of biochemical studies, we propose a mechanism in which G12 serves as the general base and a magnesium-bound water serves as a general acid.
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Affiliation(s)
- Aamir Mir
- Department of Biochemistry, Purdue University , West Lafayette, Indiana 47907, United States
| | - Barbara L Golden
- Department of Biochemistry, Purdue University , West Lafayette, Indiana 47907, United States
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50
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Košutić M, Neuner S, Ren A, Flür S, Wunderlich C, Mairhofer E, Vušurović N, Seikowski J, Breuker K, Höbartner C, Patel DJ, Kreutz C, Micura R. A Mini-Twister Variant and Impact of Residues/Cations on the Phosphodiester Cleavage of this Ribozyme Class. Angew Chem Int Ed Engl 2015; 54:15128-15133. [PMID: 26473980 DOI: 10.1002/anie.201506601] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 09/02/2015] [Indexed: 12/16/2022]
Abstract
Nucleolytic ribozymes catalyze site-specific cleavage of their phosphodiester backbones. A minimal version of the twister ribozyme is reported that lacks the phylogenetically conserved stem P1 while retaining wild-type activity. Atomic mutagenesis revealed that nitrogen atoms N1 and N3 of the adenine-6 at the cleavage site are indispensable for cleavage. By NMR spectroscopy, a pKa value of 5.1 was determined for a (13) C2-labeled adenine at this position in the twister ribozyme, which is significantly shifted compared to the pKa of the same adenine in the substrate alone. This finding pinpoints at a potential role for adenine-6 in the catalytic mechanism besides the previously identified invariant guanine-48 and a Mg(2+) ion, both of which are directly coordinated to the non-bridging oxygen atoms of the scissile phosphate; for the latter, additional evidence stems from the observation that Mn(2+) or Cd(2+) accelerated cleavage of phosphorothioate substrates. The relevance of this metal ion binding site is further emphasized by a new 2.6 Å X-ray structure of a 2'-OCH3 -U5 modified twister ribozyme.
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Affiliation(s)
- Marija Košutić
- Institute of Organic Chemistry and Center for Molecular Biosciences CMBI, Leopold-Franzens University, Innrain 80-82, 6020 Innsbruck (Austria)
| | - Sandro Neuner
- Institute of Organic Chemistry and Center for Molecular Biosciences CMBI, Leopold-Franzens University, Innrain 80-82, 6020 Innsbruck (Austria)
| | - Aiming Ren
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, NY, New York 10065 (USA)
| | - Sara Flür
- Institute of Organic Chemistry and Center for Molecular Biosciences CMBI, Leopold-Franzens University, Innrain 80-82, 6020 Innsbruck (Austria)
| | - Christoph Wunderlich
- Institute of Organic Chemistry and Center for Molecular Biosciences CMBI, Leopold-Franzens University, Innrain 80-82, 6020 Innsbruck (Austria)
| | - Elisabeth Mairhofer
- Institute of Organic Chemistry and Center for Molecular Biosciences CMBI, Leopold-Franzens University, Innrain 80-82, 6020 Innsbruck (Austria)
| | - Nikola Vušurović
- Institute of Organic Chemistry and Center for Molecular Biosciences CMBI, Leopold-Franzens University, Innrain 80-82, 6020 Innsbruck (Austria)
| | - Jan Seikowski
- Max Planck Institute of Biophysical Chemistry and Institute of Organic and Biomolecular Chemistry, Georg August University of Göttingen, 37077 Göttingen (Germany)
| | - Kathrin Breuker
- Institute of Organic Chemistry and Center for Molecular Biosciences CMBI, Leopold-Franzens University, Innrain 80-82, 6020 Innsbruck (Austria)
| | - Claudia Höbartner
- Max Planck Institute of Biophysical Chemistry and Institute of Organic and Biomolecular Chemistry, Georg August University of Göttingen, 37077 Göttingen (Germany)
| | - Dinshaw J Patel
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, NY, New York 10065 (USA)
| | - Christoph Kreutz
- Institute of Organic Chemistry and Center for Molecular Biosciences CMBI, Leopold-Franzens University, Innrain 80-82, 6020 Innsbruck (Austria)
| | - Ronald Micura
- Institute of Organic Chemistry and Center for Molecular Biosciences CMBI, Leopold-Franzens University, Innrain 80-82, 6020 Innsbruck (Austria)
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