1
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Toews S, Wacker A, Faison EM, Duchardt-Ferner E, Richter C, Mathieu D, Bottaro S, Zhang Q, Schwalbe H. The 5'-terminal stem-loop RNA element of SARS-CoV-2 features highly dynamic structural elements that are sensitive to differences in cellular pH. Nucleic Acids Res 2024; 52:7971-7986. [PMID: 38842942 PMCID: PMC11260494 DOI: 10.1093/nar/gkae477] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 05/16/2024] [Accepted: 05/22/2024] [Indexed: 07/23/2024] Open
Abstract
We present the nuclear magnetic resonance spectroscopy (NMR) solution structure of the 5'-terminal stem loop 5_SL1 (SL1) of the SARS-CoV-2 genome. SL1 contains two A-form helical elements and two regions with non-canonical structure, namely an apical pyrimidine-rich loop and an asymmetric internal loop with one and two nucleotides at the 5'- and 3'-terminal part of the sequence, respectively. The conformational ensemble representing the averaged solution structure of SL1 was validated using NMR residual dipolar coupling (RDC) and small-angle X-ray scattering (SAXS) data. We show that the internal loop is the major binding site for fragments of low molecular weight. This internal loop of SL1 can be stabilized by an A12-C28 interaction that promotes the transient formation of an A+•C base pair. As a consequence, the pKa of the internal loop adenosine A12 is shifted to 5.8, compared to a pKa of 3.63 of free adenosine. Furthermore, applying a recently developed pH-differential mutational profiling (PD-MaP) approach, we not only recapitulated our NMR findings of SL1 but also unveiled multiple sites potentially sensitive to pH across the 5'-UTR of SARS-CoV-2.
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Affiliation(s)
- Sabrina Toews
- Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
- Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
| | - Anna Wacker
- Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
- Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
| | - Edgar M Faison
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC27599, USA
| | - Elke Duchardt-Ferner
- Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
- Institute of Molecular Biosciences, Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
| | - Christian Richter
- Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
- Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
| | - Daniel Mathieu
- Bruker BioSpin GmbH, Ettlingen, Baden-Württemberg 76275, Germany
| | - Sandro Bottaro
- Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen 2200, Denmark
| | - Qi Zhang
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC27599, USA
| | - Harald Schwalbe
- Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
- Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
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2
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Chyży P, Kulik M, Shinobu A, Re S, Sugita Y, Trylska J. Molecular dynamics in multidimensional space explains how mutations affect the association path of neomycin to a riboswitch. Proc Natl Acad Sci U S A 2024; 121:e2317197121. [PMID: 38579011 PMCID: PMC11009640 DOI: 10.1073/pnas.2317197121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Accepted: 02/15/2024] [Indexed: 04/07/2024] Open
Abstract
Riboswitches are messenger RNA (mRNA) fragments binding specific small molecules to regulate gene expression. A synthetic N1 riboswitch, inserted into yeast mRNA controls the translation of a reporter gene in response to neomycin. However, its regulatory activity is sensitive to single-point RNA mutations, even those distant from the neomycin binding site. While the association paths of neomycin to N1 and its variants remain unknown, recent fluorescence kinetic experiments indicate a two-step process driven by conformational selection. This raises the question of which step is affected by mutations. To address this, we performed all-atom two-dimensional replica-exchange molecular dynamics simulations for N1 and U14C, U14C[Formula: see text], U15A, and A17G mutants, ensuring extensive conformational sampling of both RNA and neomycin. The obtained neomycin association and binding paths, along with multidimensional free-energy profiles, revealed a two-step binding mechanism, consisting of conformational selection and induced fit. Neomycin binds to a preformed N1 conformation upon identifying a stable upper stem and U-turn motif in the riboswitch hairpin. However, the positioning of neomycin in the binding site occurs at different RNA-neomycin distances for each mutant, which may explain their different regulatory activities. The subsequent induced fit arises from the interactions of the neomycin's N3 amino group with RNA, causing the G9 backbone to rearrange. In the A17G mutant, the critical C6-A17/G17 stacking forms at a closer RNA-neomycin distance compared to N1. These findings together with estimated binding free energies coincide with experiments and elucidate why the A17G mutation decreases and U15A enhances N1 activity in response to neomycin.
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Affiliation(s)
- Piotr Chyży
- Centre of New Technologies, University of Warsaw, 02-097Warsaw, Poland
| | - Marta Kulik
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, 02-093Warsaw, Poland
| | - Ai Shinobu
- Laboratory for Biomolecular Function Simulation, RIKEN Center for Biosystems Dynamics Research, 650-0047Kobe, Japan
| | - Suyong Re
- Laboratory for Biomolecular Function Simulation, RIKEN Center for Biosystems Dynamics Research, 650-0047Kobe, Japan
- Artificial Intelligence Center for Health and Biomedical Research, National Institutes of Biomedical Innovation, Health, and Nutrition, 567-0085Ibaraki, Japan
| | - Yuji Sugita
- Laboratory for Biomolecular Function Simulation, RIKEN Center for Biosystems Dynamics Research, 650-0047Kobe, Japan
- Theoretical Molecular Science Laboratory, RIKEN Cluster for Pioneering Research, 351-0198Wako, Japan
- RIKEN Center for Computational Science, 650-0047Kobe, Japan
| | - Joanna Trylska
- Centre of New Technologies, University of Warsaw, 02-097Warsaw, Poland
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3
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Vögele J, Duchardt-Ferner E, Kruse H, Zhang Z, Sponer J, Krepl M, Wöhnert J. Structural and dynamic effects of pseudouridine modifications on noncanonical interactions in RNA. RNA (NEW YORK, N.Y.) 2023; 29:790-807. [PMID: 36868785 PMCID: PMC10187676 DOI: 10.1261/rna.079506.122] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 02/10/2023] [Indexed: 05/18/2023]
Abstract
Pseudouridine is the most frequently naturally occurring RNA modification, found in all classes of biologically functional RNAs. Compared to uridine, pseudouridine contains an additional hydrogen bond donor group and is therefore widely regarded as a structure stabilizing modification. However, the effects of pseudouridine modifications on the structure and dynamics of RNAs have so far only been investigated in a limited number of different structural contexts. Here, we introduced pseudouridine modifications into the U-turn motif and the adjacent U:U closing base pair of the neomycin-sensing riboswitch (NSR)-an extensively characterized model system for RNA structure, ligand binding, and dynamics. We show that the effects of replacing specific uridines with pseudouridines on RNA dynamics crucially depend on the exact location of the replacement site and can range from destabilizing to locally or even globally stabilizing. By using a combination of NMR spectroscopy, MD simulations and QM calculations, we rationalize the observed effects on a structural and dynamical level. Our results will help to better understand and predict the consequences of pseudouridine modifications on the structure and function of biologically important RNAs.
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Affiliation(s)
- Jennifer Vögele
- Institute of Molecular Biosciences and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-University Frankfurt, 60438 Frankfurt, Germany
| | - Elke Duchardt-Ferner
- Institute of Molecular Biosciences and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-University Frankfurt, 60438 Frankfurt, Germany
| | - Holger Kruse
- Institute of Biophysics of the Czech Academy of Sciences, 612 65 Brno, Czech Republic
| | - Zhengyue Zhang
- Institute of Biophysics of the Czech Academy of Sciences, 612 65 Brno, Czech Republic
- CEITEC-Central European Institute of Technology, Masaryk University, 625 00 Brno, Czech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, 625 00 Brno, Czech Republic
| | - Jiri Sponer
- Institute of Biophysics of the Czech Academy of Sciences, 612 65 Brno, Czech Republic
| | - Miroslav Krepl
- Institute of Biophysics of the Czech Academy of Sciences, 612 65 Brno, Czech Republic
| | - Jens Wöhnert
- Institute of Molecular Biosciences and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-University Frankfurt, 60438 Frankfurt, Germany
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4
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Mráziková K, Kruse H, Mlýnský V, Auffinger P, Šponer J. Multiscale Modeling of Phosphate···π Contacts in RNA U-Turns Exposes Differences between Quantum-Chemical and AMBER Force Field Descriptions. J Chem Inf Model 2022; 62:6182-6200. [PMID: 36454943 DOI: 10.1021/acs.jcim.2c01064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Phosphate···π, also called anion···π, contacts occur between nucleobases and anionic phosphate oxygens (OP2) in r(GNRA) and r(UNNN) U-turn motifs (N = A,G,C,U; R = A,G). These contacts were investigated using state-of-the-art quantum-chemical methods (QM) to characterize their physicochemical properties and to serve as a reference to evaluate AMBER force field (AFF) performance. We found that phosphate···π interaction energies calculated with the AFF for dimethyl phosphate···nucleobase model systems are less stabilizing in comparison with double-hybrid DFT and that minimum contact distances are larger for all nucleobases. These distance stretches are also observed in large-scale AFF vs QM/MM computations and classical molecular dynamics (MD) simulations on several r(gcGNRAgc) tetraloop hairpins when compared to experimental data extracted from X-ray/cryo-EM structures (res. ≤ 2.5 Å) using the WebFR3D bioinformatic tool. MD simulations further revealed shifted OP2/nucleobase positions. We propose that discrepancies between the QM and AFF result from a combination of missing polarization in the AFF combined with too large AFF Lennard-Jones (LJ) radii of nucleobase carbon atoms in addition to an exaggerated short-range repulsion of the r-12 LJ repulsive term. We compared these results with earlier data gathered on lone pair···π contacts in CpG Z-steps occurring in r(UNCG) tetraloops. In both instances, charge transfer calculations do not support any significant n → π* donation effects. We also investigated thiophosphate···π contacts that showed reduced stabilizing interaction energies when compared to phosphate···π contacts. Thus, we challenge suggestions that the experimentally observed enhanced thermodynamic stability of phosphorothioated r(GNRA) tetraloops can be explained by larger London dispersion.
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Affiliation(s)
- Klaudia Mráziková
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65Brno, Czech Republic.,National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 625 00Brno, Czech Republic
| | - Holger Kruse
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65Brno, Czech Republic
| | - Vojtěch Mlýnský
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65Brno, Czech Republic
| | - Pascal Auffinger
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg67084, France
| | - Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65Brno, Czech Republic
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5
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Mair S, Erharter K, Renard E, Brillet K, Brunner M, Lusser A, Kreutz C, Ennifar E, Micura R. Towards a comprehensive understanding of RNA deamination: synthesis and properties of xanthosine-modified RNA. Nucleic Acids Res 2022; 50:6038-6051. [PMID: 35687141 PMCID: PMC9226506 DOI: 10.1093/nar/gkac477] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 04/28/2022] [Accepted: 05/20/2022] [Indexed: 12/25/2022] Open
Abstract
Nucleobase deamination, such as A-to-I editing, represents an important posttranscriptional modification of RNA. When deamination affects guanosines, a xanthosine (X) containing RNA is generated. However, the biological significance and chemical consequences on RNA are poorly understood. We present a comprehensive study on the preparation and biophysical properties of X-modified RNA. Thermodynamic analyses revealed that base pairing strength is reduced to a level similar to that observed for a G•U replacement. Applying NMR spectroscopy and X-ray crystallography, we demonstrate that X can form distinct wobble geometries with uridine depending on the sequence context. In contrast, X pairing with cytidine occurs either through wobble geometry involving protonated C or in Watson–Crick-like arrangement. This indicates that the different pairing modes are of comparable stability separated by low energetic barriers for switching. Furthermore, we demonstrate that the flexible pairing properties directly affect the recognition of X-modified RNA by reverse transcription enzymes. Primer extension assays and PCR-based sequencing analysis reveal that X is preferentially read as G or A and that the ratio depends on the type of reverse transcriptase. Taken together, our results elucidate important properties of X-modified RNA paving the way for future studies on its biological significance.
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Affiliation(s)
- Stefan Mair
- Institute of Organic Chemistry, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Kevin Erharter
- Institute of Organic Chemistry, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Eva Renard
- Architecture et Réactivité de l'ARN - CNRS UPR 9002, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, 67000 Strasbourg, France
| | - Karl Brillet
- Architecture et Réactivité de l'ARN - CNRS UPR 9002, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, 67000 Strasbourg, France
| | - Melanie Brunner
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Alexandra Lusser
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Christoph Kreutz
- Institute of Organic Chemistry, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Eric Ennifar
- Architecture et Réactivité de l'ARN - CNRS UPR 9002, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, 67000 Strasbourg, France
| | - Ronald Micura
- Institute of Organic Chemistry, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
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6
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Chyży P, Kulik M, Re S, Sugita Y, Trylska J. Mutations of N1 Riboswitch Affect its Dynamics and Recognition by Neomycin Through Conformational Selection. Front Mol Biosci 2021; 8:633130. [PMID: 33708793 PMCID: PMC7942488 DOI: 10.3389/fmolb.2021.633130] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/07/2021] [Indexed: 11/13/2022] Open
Abstract
Short, structured fragments of non-coding mRNA may act as molecular switches upon binding specific ligands, regulating the translation of proteins encoded downstream this mRNA sequence. One switch, called riboswitch N1, is regulated by aminoglycosides such as neomycin. Nucleobase mutations in the apical loop, although distant from the binding pocket, significantly affect neomycin affinity and riboswitch regulatory efficiency. To explain this influence, we conducted molecular dynamics simulations using generalized replica exchange with solute tempering (gREST). Translation assay of a reporter protein in a yeast system shows that mutating A17 to G in the riboswitch apical loop reduces 6-fold the translation regulation efficiency of the mutant. Indeed, simulations of the unbound riboswitch show that G17 frequently stacks with base 7, while base 8 is stabilized towards the binding site in a way that it may interfere with the conformational selection mechanism and decrease riboswitch regulatory activity. In the riboswitch complexes, this single-point A to G mutation disrupts a strong hydrogen bond between nucleotides 5 and 17 and, instead, a new hydrogen bond between residue 17 and neomycin is created. This change forces neomycin to occupy a slightly shifted position in the binding pocket, which increases neomycin flexibility. Our simulations of the U14C mutation suggest that the riboswitch complex with neomycin is more stable if cytosine 14 is protonated. A hydrogen bond between the RNA phosphate and protonated cytosine appears as the stabilizing factor. Also, based on the cell-free translation assay and isothermal titration calorimetry experiments, mutations of nucleotides 14 and 15 affect only slightly the riboswitch ability to bind the ligand and its activity. Indeed, the simulation of the unbound U15A mutant suggests conformations preformed for ligand binding, which may explain slightly higher regulatory activity of this mutant. Overall, our results corroborate the in vivo and in vitro experiments on the N1 riboswitch-neomycin system, detail the relationship between nucleobase mutations and RNA dynamics, and reveal the conformations playing the major role in the conformational selection mechanism.
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Affiliation(s)
- Piotr Chyży
- Centre of New Technologies, University of Warsaw, Warsaw, Poland.,Faculty of Physics, University of Warsaw, Warsaw, Poland
| | - Marta Kulik
- Centre of New Technologies, University of Warsaw, Warsaw, Poland.,Department of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
| | - Suyong Re
- RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan.,National Institutes of Biomedical Innovation, Health and Nutrition, Ibaraki, Japan
| | - Yuji Sugita
- RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan.,RIKEN Cluster for Pioneering Research (CPR), Wako, Japan.,RIKEN Center for Computational Science, Kobe, Japan
| | - Joanna Trylska
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
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7
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Zhang Z, Vögele J, Mráziková K, Kruse H, Cang X, Wöhnert J, Krepl M, Šponer J. Phosphorothioate Substitutions in RNA Structure Studied by Molecular Dynamics Simulations, QM/MM Calculations, and NMR Experiments. J Phys Chem B 2021; 125:825-840. [PMID: 33467852 DOI: 10.1021/acs.jpcb.0c10192] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Phosphorothioates (PTs) are important chemical modifications of the RNA backbone where a single nonbridging oxygen of the phosphate is replaced with a sulfur atom. PT can stabilize RNAs by protecting them from hydrolysis and is commonly used as a tool to explore their function. It is, however, unclear what basic physical effects PT has on RNA stability and electronic structure. Here, we present molecular dynamics (MD) simulations, quantum mechanical (QM) calculations, and NMR spectroscopy measurements, exploring the effects of PT modifications in the structural context of the neomycin-sensing riboswitch (NSR). The NSR is the smallest biologically functional riboswitch with a well-defined structure stabilized by a U-turn motif. Three of the signature interactions of the U-turn: an H-bond, an anion-π interaction, and a potassium binding site; are formed by RNA phosphates, making the NSR an ideal model for studying how PT affects RNA structure and dynamics. By comparing with high-level QM calculations, we reveal the distinct physical properties of the individual interactions facilitated by the PT. The sulfur substitution, besides weakening the direct H-bond interaction, reduces the directionality of H-bonding while increasing its dispersion and induction components. It also reduces the induction and increases the dispersion component of the anion-π stacking. The sulfur force-field parameters commonly employed in the literature do not reflect these distinctions, leading to the unsatisfactory description of PT in simulations of the NSR. We show that it is not possible to accurately describe the PT interactions using one universal set of van der Waals sulfur parameters and provide suggestions for improving the force-field performance.
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Affiliation(s)
- Zhengyue Zhang
- CEITEC-Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.,Faculty of Science, Masaryk University, Kotlarska 2, 602 00 Brno, Czech Republic
| | - Jennifer Vögele
- Institute of Molecular Biosciences and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-University Frankfurt, Max-von-Laue-Straße 9, 60438 Frankfurt, Germany
| | - Klaudia Mráziková
- Faculty of Science, Masaryk University, Kotlarska 2, 602 00 Brno, Czech Republic.,Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, 612 65 Brno, Czech Republic
| | - Holger Kruse
- Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, 612 65 Brno, Czech Republic
| | - Xiaohui Cang
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Jens Wöhnert
- Institute of Molecular Biosciences and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-University Frankfurt, Max-von-Laue-Straße 9, 60438 Frankfurt, Germany
| | - Miroslav Krepl
- Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, 612 65 Brno, Czech Republic
| | - Jiří Šponer
- CEITEC-Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.,Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, 612 65 Brno, Czech Republic
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8
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Kulik M, Mori T, Sugita Y, Trylska J. Molecular mechanisms for dynamic regulation of N1 riboswitch by aminoglycosides. Nucleic Acids Res 2019; 46:9960-9970. [PMID: 30239867 PMCID: PMC6212780 DOI: 10.1093/nar/gky833] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 09/07/2018] [Indexed: 01/14/2023] Open
Abstract
A synthetic riboswitch N1, inserted into the 5'-untranslated mRNA region of yeast, regulates gene expression upon binding ribostamycin and neomycin. Interestingly, a similar aminoglycoside, paromomycin, differing from neomycin by only one substituent (amino versus hydroxyl), also binds to the N1 riboswitch, but without affecting gene expression, despite NMR evidence that the N1 riboswitch binds all aminoglycosides in a similar way. Here, to explore the details of structural dynamics of the aminoglycoside-N1 riboswitch complexes, we applied all-atom molecular dynamics (MD) and temperature replica-exchange MD simulations in explicit solvent. Indeed, we found that ribostamycin and neomycin affect riboswitch dynamics similarly but paromomycin allows for more flexibility because its complex lacks the contact between the distinctive 6' hydroxyl group and the G9 phosphate. Instead, a transient hydrogen bond of 6'-OH with A17 is formed, which partially diminishes interactions between the bulge and apical loop of the riboswitch, likely contributing to riboswitch inactivity. In many ways, the paromomycin complex mimics the conformations, interactions, and Na+ distribution of the free riboswitch. The MD-derived interaction network helps understand why riboswitch activity depends on aminoglycoside type, whereas for another aminoglycoside-binding site, aminoacyl-tRNA site in 16S rRNA, activity is not discriminatory.
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Affiliation(s)
- Marta Kulik
- RIKEN, Hirosawa, Wako City, Saitama 351-0198, Japan.,Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | | | - Yuji Sugita
- RIKEN, Hirosawa, Wako City, Saitama 351-0198, Japan
| | - Joanna Trylska
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
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9
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Pasquali S, Frezza E, Barroso da Silva FL. Coarse-grained dynamic RNA titration simulations. Interface Focus 2019; 9:20180066. [PMID: 31065339 DOI: 10.1098/rsfs.2018.0066] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/13/2019] [Indexed: 12/11/2022] Open
Abstract
Electrostatic interactions play a pivotal role in many biomolecular processes. The molecular organization and function in biological systems are largely determined by these interactions. Owing to the highly negative charge of RNA, the effect is expected to be more pronounced in this system. Moreover, RNA base pairing is dependent on the charge of the base, giving rise to alternative secondary and tertiary structures. The equilibrium between uncharged and charged bases is regulated by the solution pH, which is therefore a key environmental condition influencing the molecule's structure and behaviour. By means of constant-pH Monte Carlo simulations based on a fast proton titration scheme, coupled with the coarse-grained model HiRE-RNA, molecular dynamic simulations of RNA molecules at constant pH enable us to explore the RNA conformational plasticity at different pH values as well as to compute electrostatic properties as local pK a values for each nucleotide.
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Affiliation(s)
- S Pasquali
- Laboratoire de Cristallographie et RMN Biologiques, CNRS UMR 8015, Université Paris Descartes, Paris 75006, France
| | - E Frezza
- Laboratoire de Cristallographie et RMN Biologiques, CNRS UMR 8015, Université Paris Descartes, Paris 75006, France
| | - F L Barroso da Silva
- Departamento de Física e Química, Faculdade de Ciência s Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do café, s/no, Ribeirão Preto, SP BR-14040-903, Brazil.,Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA
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10
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Keller H, Weickhmann AK, Bock T, Wöhnert J. Adenine protonation enables cyclic-di-GMP binding to cyclic-GAMP sensing riboswitches. RNA (NEW YORK, N.Y.) 2018; 24:1390-1402. [PMID: 30006500 PMCID: PMC6140456 DOI: 10.1261/rna.067470.118] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Accepted: 07/09/2018] [Indexed: 05/22/2023]
Abstract
In certain structural or functional contexts, RNA structures can contain protonated nucleotides. However, a direct role for stably protonated nucleotides in ligand binding and ligand recognition has not yet been demonstrated unambiguously. Previous X-ray structures of c-GAMP binding riboswitch aptamer domains in complex with their near-cognate ligand c-di-GMP suggest that an adenine of the riboswitch either forms two hydrogen bonds to a G nucleotide of the ligand in the unusual enol tautomeric form or that the adenine in its N1 protonated form binds the G nucleotide of the ligand in its canonical keto tautomeric state. By using NMR spectroscopy we demonstrate that the c-GAMP riboswitches bind c-di-GMP using a stably protonated adenine in the ligand binding pocket. Thereby, we provide novel insights into the putative biological functions of protonated nucleotides in RNA, which in this case influence the ligand selectivity in a riboswitch.
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Affiliation(s)
- Heiko Keller
- Institute for Molecular Biosciences and Center of Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - A Katharina Weickhmann
- Institute for Molecular Biosciences and Center of Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Thomas Bock
- Institute for Molecular Biosciences and Center of Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Jens Wöhnert
- Institute for Molecular Biosciences and Center of Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
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11
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Krepl M, Vögele J, Kruse H, Duchardt-Ferner E, Wöhnert J, Sponer J. An intricate balance of hydrogen bonding, ion atmosphere and dynamics facilitates a seamless uracil to cytosine substitution in the U-turn of the neomycin-sensing riboswitch. Nucleic Acids Res 2018; 46:6528-6543. [PMID: 29893898 PMCID: PMC6061696 DOI: 10.1093/nar/gky490] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 05/23/2018] [Indexed: 01/04/2023] Open
Abstract
The neomycin sensing riboswitch is the smallest biologically functional RNA riboswitch, forming a hairpin capped with a U-turn loop-a well-known RNA motif containing a conserved uracil. It was shown previously that a U→C substitution of the eponymous conserved uracil does not alter the riboswitch structure due to C protonation at N3. Furthermore, cytosine is evolutionary permitted to replace uracil in other U-turns. Here, we use molecular dynamics simulations to study the molecular basis of this substitution in the neomycin sensing riboswitch and show that a structure-stabilizing monovalent cation-binding site in the wild-type RNA is the main reason for its negligible structural effect. We then use NMR spectroscopy to confirm the existence of this cation-binding site and to demonstrate its effects on RNA stability. Lastly, using quantum chemical calculations, we show that the cation-binding site is altering the electronic environment of the wild-type U-turn so that it is more similar to the cytosine mutant. The study reveals an amazingly complex and delicate interplay between various energy contributions shaping up the 3D structure and evolution of nucleic acids.
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Affiliation(s)
- Miroslav Krepl
- Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, 612 65 Brno, Czech Republic
| | - Jennifer Vögele
- Institute of Molecular Biosciences and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Holger Kruse
- Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, 612 65 Brno, Czech Republic
| | - Elke Duchardt-Ferner
- Institute of Molecular Biosciences and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Jens Wöhnert
- Institute of Molecular Biosciences and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Jiri Sponer
- Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, 612 65 Brno, Czech Republic
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University Olomouc, 17. listopadu 12, 771 46 Olomouc, Czech Republic
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12
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Frankel EA, Bevilacqua PC. Complexity in pH-Dependent Ribozyme Kinetics: Dark pK a Shifts and Wavy Rate-pH Profiles. Biochemistry 2017; 57:483-488. [PMID: 29271644 DOI: 10.1021/acs.biochem.7b00784] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Charged bases occur in RNA enzymes, or ribozymes, where they play key roles in catalysis. Cationic bases donate protons and perform electrostatic catalysis, while anionic bases accept protons. We previously published simulations of rate-pH profiles for ribozymes in terms of species plots for the general acid and general base that have been useful for understanding how ribozymes respond to pH. In that study, we did not consider interaction between the general acid and general base or interaction with other species on the RNA. Since that report, diverse small ribozyme classes have been discovered, many of which have charged nucleobases or metal ions in the active site that can either directly interact and participate in catalysis or indirectly interact as "influencers". Herein, we simulate experimental rate-pH profiles in terms of species plots in which reverse protonated charged nucleobases interact. These analyses uncover two surprising features of pH-dependent enzyme kinetics. (1) Cooperativity between the general acid and general base enhances population of the functional forms of a ribozyme and manifests itself as hidden or "dark" pKa shifts, real pKa shifts that accelerate the reaction but are not readily observed by standard experimental approaches, and (2) influencers favorably shift the pKas of proton-transferring nucleobases and manifest themselves as "wavy" rate-pH profiles. We identify parallels with the protein enzyme literature, including reverse protonation and wavelike behavior, while pointing out that RNA is more prone to reverse protonation. The complexities uncovered, which arise from simple pairwise interactions, should aid deconvolution of complex rate-pH profiles for RNA and protein enzymes and suggest veiled catalytic devices for promoting catalysis that can be tested by experiment and calculation.
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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
| | - 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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13
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Duchardt-Ferner E, Wöhnert J. NMR experiments for the rapid identification of P=O···H-X type hydrogen bonds in nucleic acids. JOURNAL OF BIOMOLECULAR NMR 2017; 69:101-110. [PMID: 29032519 DOI: 10.1007/s10858-017-0140-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 10/05/2017] [Indexed: 05/24/2023]
Abstract
Hydrogen bonds involving the backbone phosphate groups occur with high frequency in functional RNA molecules. They are often found in well-characterized tertiary structural motifs presenting powerful probes for the rapid identification of these motifs for structure elucidation purposes. We have shown recently that stable hydrogen bonds to the phosphate backbone can in principle be detected by relatively simple NMR-experiments, providing the identity of both the donor hydrogen and the acceptor phosphorous within the same experiment (Duchardt-Ferner et al., Angew Chem Int Ed Engl 50:7927-7930, 2011). However, for imino and hydroxyl hydrogen bond donor groups rapidly exchanging with the solvent as well as amino groups broadened by conformational exchange experimental sensitivity is severely hampered by extensive line broadening. Here, we present improved methods for the rapid identification of hydrogen bonds to phosphate groups in nucleic acids by NMR. The introduction of the SOFAST technique into 1H,31P-correlation experiments as well as a BEST-HNP experiment exploiting 3hJN,P rather than 2hJH,P coupling constants enables the rapid and sensitive identification of these hydrogen bonds in RNA. The experiments are applicable for larger RNAs (up to ~ 100-nt), for donor groups influenced by conformational exchange processes such as amino groups and for hydrogen bonds with rather labile hydrogens such as 2'-OH groups as well as for moderate sample concentrations. Interestingly, the size of the through-hydrogen bond scalar coupling constants depends not only on the type of the donor group but also on the structural context. The largest coupling constants were measured for hydrogen bonds involving the imino groups of protonated cytosine nucleotides as donors.
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Affiliation(s)
- Elke Duchardt-Ferner
- Institute for Molecular Biosciences, Goethe-University, Frankfurt/M., Max-von-Laue-Str. 9, 60438, Frankfurt, Germany
- Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-University, Frankfurt/M., Max-von-Laue-Str. 9, 60438, Frankfurt, Germany
| | - Jens Wöhnert
- Institute for Molecular Biosciences, Goethe-University, Frankfurt/M., Max-von-Laue-Str. 9, 60438, Frankfurt, Germany.
- Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-University, Frankfurt/M., Max-von-Laue-Str. 9, 60438, Frankfurt, Germany.
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14
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Barroso da Silva FL, Derreumaux P, Pasquali S. Fast coarse-grained model for RNA titration. J Chem Phys 2017; 146:035101. [PMID: 28109220 DOI: 10.1063/1.4972986] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
A new numerical scheme for RNA (ribonucleic acid) titration based on the Debye-Hückel framework for the salt description is proposed in an effort to reduce the computational costs for further applications to study protein-RNA systems. By means of different sets of Monte Carlo simulations, we demonstrated that this new scheme is able to correctly reproduce the experimental titration behavior and salt pKa shifts. In comparison with other theoretical approaches, similar or even better outcomes are achieved at much lower computational costs. The model was tested on the lead-dependent ribozyme, the branch-point helix, and the domain 5 from Azotobacter vinelandii Intron 5.
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Affiliation(s)
- Fernando Luís Barroso da Silva
- Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ave. do café, s/no, BR-14040-903 Ribeirão Preto, São Paulo, Brazil
| | - Philippe Derreumaux
- Laboratoire de Biochimie Theórique, UPR 9080 CNRS, Institut de Biologie Physico Chimique, Université Paris Diderot - Paris 7 et Université Sorbonne Paris Cité, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Samuela Pasquali
- Laboratoire de Biochimie Theórique, UPR 9080 CNRS, Institut de Biologie Physico Chimique, Université Paris Diderot - Paris 7 et Université Sorbonne Paris Cité, 13 rue Pierre et Marie Curie, 75005 Paris, France
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15
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Martinez-Zapien D, Legrand P, McEwen AG, Proux F, Cragnolini T, Pasquali S, Dock-Bregeon AC. The crystal structure of the 5΄ functional domain of the transcription riboregulator 7SK. Nucleic Acids Res 2017; 45:3568-3579. [PMID: 28082395 PMCID: PMC5389472 DOI: 10.1093/nar/gkw1351] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 01/06/2017] [Indexed: 12/22/2022] Open
Abstract
In vertebrates, the 7SK RNA forms the scaffold of a complex, which regulates transcription pausing of RNA-polymerase II. By binding to the HEXIM protein, the complex comprising proteins LARP7 and MePCE captures the positive transcription elongation factor P-TEFb and prevents phosphorylation of pausing factors. The HEXIM-binding site embedded in the 5΄-hairpin of 7SK (HP1) encompasses a short signature sequence, a GAUC repeat framed by single-stranded uridines. The present crystal structure of HP1 shows a remarkably straight helical stack involving several unexpected triples formed at a central region. Surprisingly, two uridines of the signature sequence make triple interactions in the major groove of the (GAUC)2. The third uridine is turned outwards or inward, wedging between the other uridines, thus filling the major groove. A molecular dynamics simulation indicates that these two conformations of the signature sequence represent stable alternatives. Analyses of the interaction with the HEXIM protein confirm the importance of the triple interactions at the signature sequence. Altogether, the present structural analysis of 7SK HP1 highlights an original mechanism of swapping bases, which could represent a possible ‘7SK signature’ and provides new insight into the functional importance of the plasticity of RNA.
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Affiliation(s)
- Denise Martinez-Zapien
- Biotechnologie et signalisation cellulaire, CNRS UMR 7242, Ecole Supérieure de Biotechnologie de Strasbourg, F-67412 Illkirch, France
| | - Pierre Legrand
- Synchrotron SOLEIL, L'Orme des Merisiers, F-91190 Gif-sur-Yvette, France
| | - Alastair G McEwen
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Florence Proux
- Department of functional genomics, CNRS UMR 8197, Institut de Biologie de l΄Ecole Normale Supérieure F-75005 Paris, France.,Department of functional genomics, INSERM-U1024, Institut de Biologie de l΄Ecole Normale Supérieure F-75005 Paris, France
| | | | - Samuela Pasquali
- Laboratoire de Biochimie Théorique, IBPC, CNRS UPR 9080, Université Sorbonne Paris Cite, Paris Diderot, 75005 Paris, France
| | - Anne-Catherine Dock-Bregeon
- Department of functional genomics, CNRS UMR 8197, Institut de Biologie de l΄Ecole Normale Supérieure F-75005 Paris, France.,Department of functional genomics, INSERM-U1024, Institut de Biologie de l΄Ecole Normale Supérieure F-75005 Paris, France.,Sorbonne Universités UPMC, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff cedex, France.,CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff cedex, France
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16
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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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17
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D'Ascenzo L, Leonarski F, Vicens Q, Auffinger P. Revisiting GNRA and UNCG folds: U-turns versus Z-turns in RNA hairpin loops. RNA (NEW YORK, N.Y.) 2017; 23:259-269. [PMID: 27999116 PMCID: PMC5311481 DOI: 10.1261/rna.059097.116] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 11/29/2016] [Indexed: 06/06/2023]
Abstract
When thinking about RNA three-dimensional structures, coming across GNRA and UNCG tetraloops is perceived as a boon since their folds have been extensively described. Nevertheless, analyzing loop conformations within RNA and RNP structures led us to uncover several instances of GNRA and UNCG loops that do not fold as expected. We noticed that when a GNRA does not assume its "natural" fold, it adopts the one we typically associate with a UNCG sequence. The same folding interconversion may occur for loops with UNCG sequences, for instance within tRNA anticodon loops. Hence, we show that some structured tetranucleotide sequences starting with G or U can adopt either of these folds. The underlying structural basis that defines these two fold types is the mutually exclusive stacking of a backbone oxygen on either the first (in GNRA) or the last nucleobase (in UNCG), generating an oxygen-π contact. We thereby propose to refrain from using sequences to distinguish between loop conformations. Instead, we suggest using descriptors such as U-turn (for "GNRA-type" folds) and a newly described Z-turn (for "UNCG-type" folds). Because tetraloops adopt for the largest part only two (inter)convertible turns, we are better able to interpret from a structural perspective loop interchangeability occurring in ribosomes and viral RNA. In this respect, we propose a general view on the inclination for a given sequence to adopt (or not) a specific fold. We also suggest how long-noncoding RNAs may adopt discrete but transient structures, which are therefore hard to predict.
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Affiliation(s)
- Luigi D'Ascenzo
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, F-67000 Strasbourg, France
| | - Filip Leonarski
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, F-67000 Strasbourg, France
- Faculty of Chemistry, University of Warsaw, 02-093 Warsaw, Poland
| | - Quentin Vicens
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, F-67000 Strasbourg, France
| | - Pascal Auffinger
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, F-67000 Strasbourg, France
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18
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Wolter AC, Weickhmann AK, Nasiri AH, Hantke K, Ohlenschläger O, Wunderlich CH, Kreutz C, Duchardt‐Ferner E, Wöhnert J. Ein stabil protoniertes Adenin‐Nukleotid mit einem extrem verschobenen p
K
a
‐Wert stabilisiert die Tertiärstruktur eines GTP‐bindenden RNA‐Aptamers. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201609184] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Antje C. Wolter
- Institut für Molekulare Biowissenschaften und Zentrum für Biomolekulare Magnetische Resonanz (BMRZ) Goethe-Universität Frankfurt Max-von-Laue-Straße 9 60438 Frankfurt/Main Deutschland
| | - A. Katharina Weickhmann
- Institut für Molekulare Biowissenschaften und Zentrum für Biomolekulare Magnetische Resonanz (BMRZ) Goethe-Universität Frankfurt Max-von-Laue-Straße 9 60438 Frankfurt/Main Deutschland
| | - Amir H. Nasiri
- Institut für Molekulare Biowissenschaften und Zentrum für Biomolekulare Magnetische Resonanz (BMRZ) Goethe-Universität Frankfurt Max-von-Laue-Straße 9 60438 Frankfurt/Main Deutschland
| | - Katharina Hantke
- Institut für Molekulare Biowissenschaften und Zentrum für Biomolekulare Magnetische Resonanz (BMRZ) Goethe-Universität Frankfurt Max-von-Laue-Straße 9 60438 Frankfurt/Main Deutschland
| | - Oliver Ohlenschläger
- Leibniz Institut für Alternsforschung (Fritz-Lipmann-Institut) Beutenbergstraße 11 07745 Jena Deutschland
| | - Christoph H. Wunderlich
- Institut für Organische Chemie Centre for Molecular Biosciences (CMBI) Universität Innsbruck Innrain 80/82 6020 Innsbruck Österreich
| | - Christoph Kreutz
- Institut für Organische Chemie Centre for Molecular Biosciences (CMBI) Universität Innsbruck Innrain 80/82 6020 Innsbruck Österreich
| | - Elke Duchardt‐Ferner
- Institut für Molekulare Biowissenschaften und Zentrum für Biomolekulare Magnetische Resonanz (BMRZ) Goethe-Universität Frankfurt Max-von-Laue-Straße 9 60438 Frankfurt/Main Deutschland
| | - Jens Wöhnert
- Institut für Molekulare Biowissenschaften und Zentrum für Biomolekulare Magnetische Resonanz (BMRZ) Goethe-Universität Frankfurt Max-von-Laue-Straße 9 60438 Frankfurt/Main Deutschland
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19
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Wolter AC, Weickhmann AK, Nasiri AH, Hantke K, Ohlenschläger O, Wunderlich CH, Kreutz C, Duchardt-Ferner E, Wöhnert J. A Stably Protonated Adenine Nucleotide with a Highly Shifted pK a Value Stabilizes the Tertiary Structure of a GTP-Binding RNA Aptamer. Angew Chem Int Ed Engl 2016; 56:401-404. [PMID: 27885761 DOI: 10.1002/anie.201609184] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 11/01/2016] [Indexed: 12/23/2022]
Abstract
RNA tertiary structure motifs are stabilized by a wide variety of hydrogen-bonding interactions. Protonated A and C nucleotides are normally not considered to be suitable building blocks for such motifs since their pKa values are far from physiological pH. Here, we report the NMR solution structure of an in vitro selected GTP-binding RNA aptamer bound to GTP with an intricate tertiary structure. It contains a novel kind of base quartet stabilized by a protonated A residue. Owing to its unique structural environment in the base quartet, the pKa value for the protonation of this A residue in the complex is shifted by more than 5 pH units compared to the pKa for A nucleotides in single-stranded RNA. This is the largest pKa shift for an A residue in structured nucleic acids reported so far, and similar in size to the largest pKa shifts observed for amino acid side chains in proteins. Both RNA pre-folding and ligand binding contribute to the pKa shift.
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Affiliation(s)
- Antje C Wolter
- Institut für Molekulare Biowissenschaften and Zentrum für Biomolekulare Magnetische Resonanz (BMRZ), Goethe-Universität Frankfurt, Max-von-Laue Str. 9, 60438, Frankfurt/Main, Germany
| | - A Katharina Weickhmann
- Institut für Molekulare Biowissenschaften and Zentrum für Biomolekulare Magnetische Resonanz (BMRZ), Goethe-Universität Frankfurt, Max-von-Laue Str. 9, 60438, Frankfurt/Main, Germany
| | - Amir H Nasiri
- Institut für Molekulare Biowissenschaften and Zentrum für Biomolekulare Magnetische Resonanz (BMRZ), Goethe-Universität Frankfurt, Max-von-Laue Str. 9, 60438, Frankfurt/Main, Germany
| | - Katharina Hantke
- Institut für Molekulare Biowissenschaften and Zentrum für Biomolekulare Magnetische Resonanz (BMRZ), Goethe-Universität Frankfurt, Max-von-Laue Str. 9, 60438, Frankfurt/Main, Germany
| | - Oliver Ohlenschläger
- Leibniz Institut für Alternsforschung (Fritz-Lipmann-Institut), Beutenbergstrasse 11, 07745, Jena, Germany
| | - Christoph H Wunderlich
- Institute of Organic Chemistry, Centre for Molecular Biosciences (CMBI), University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria
| | - Christoph Kreutz
- Institute of Organic Chemistry, Centre for Molecular Biosciences (CMBI), University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria
| | - Elke Duchardt-Ferner
- Institut für Molekulare Biowissenschaften and Zentrum für Biomolekulare Magnetische Resonanz (BMRZ), Goethe-Universität Frankfurt, Max-von-Laue Str. 9, 60438, Frankfurt/Main, Germany
| | - Jens Wöhnert
- Institut für Molekulare Biowissenschaften and Zentrum für Biomolekulare Magnetische Resonanz (BMRZ), Goethe-Universität Frankfurt, Max-von-Laue Str. 9, 60438, Frankfurt/Main, Germany
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20
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Welty R, Hall KB. Nucleobases Undergo Dynamic Rearrangements during RNA Tertiary Folding. J Mol Biol 2016; 428:4490-4502. [PMID: 27693721 DOI: 10.1016/j.jmb.2016.09.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 08/31/2016] [Accepted: 09/15/2016] [Indexed: 02/07/2023]
Abstract
The tertiary structure of the GTPase center (GAC) of 23S ribosomal RNA (rRNA) as seen in cocrystals is extremely compact. It is stabilized by long-range hydrogen bonds and nucleobase stacking and by a triloop that forms within its three-way junction. Its folding pathway from secondary structure to tertiary structure has not been previously observed, but it was shown to require Mg2+ ions in equilibrium experiments. The fluorescent nucleotide 2-aminopurine was substituted at selected sites within the 60-nt GAC. Fluorescence intensity changes upon addition of MgCl2 were monitored over a time-course from 1ms to 100s as the RNA folds. The folding pathway is revealed here to be hierarchical through several intermediates. Observation of the nucleobases during folding provides a new perspective on the process and the pathway, revealing the dynamics of nucleobase conformational exchange during the folding transitions.
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Affiliation(s)
- Robb Welty
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Kathleen B Hall
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
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21
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Rypniewski W, Banaszak K, Kuliński T, Kiliszek A. Watson-Crick-like pairs in CCUG repeats: evidence for tautomeric shifts or protonation. RNA (NEW YORK, N.Y.) 2016; 22:22-31. [PMID: 26543073 PMCID: PMC4691832 DOI: 10.1261/rna.052399.115] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 09/19/2015] [Indexed: 05/16/2023]
Abstract
RNA transcripts that include expanded CCUG repeats are associated with myotonic dystrophy type 2. Crystal structures of two CCUG-containing oligomers show that the RNA strands associate into slipped duplexes that contain noncanonical C-U pairs that have apparently undergone tautomeric transition or protonation resulting in an unusual Watson-Crick-like pairing. The overhanging ends of the duplexes interact forming U-U pairs, which also show tautomerism. Duplexes consisting of CCUG repeats are thermodynamically less stable than the trinucleotide repeats involved in the TRED genetic disorders, but introducing LNA residues increases their stability and raises the melting temperature of the studied oligomers by ∼10°C, allowing detailed crystallographic studies. Quantum mechanical calculations were performed to test the possibility of the tautomeric transitions or protonation within the noncanonical pairs. The results indicate that tautomeric or ionic shifts of nucleobases can manifest themselves in biological systems, supplementing the canonical "rules of engagement."
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Affiliation(s)
- Wojciech Rypniewski
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704 Poznan, Poland
| | - Katarzyna Banaszak
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704 Poznan, Poland
| | - Tadeusz Kuliński
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704 Poznan, Poland
| | - Agnieszka Kiliszek
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704 Poznan, Poland
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