1
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Cowan JA. Understanding the Thermodynamics of Magnesium Binding to RNA Structural Motifs. Life (Basel) 2024; 14:765. [PMID: 38929748 PMCID: PMC11205036 DOI: 10.3390/life14060765] [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: 04/19/2024] [Revised: 06/05/2024] [Accepted: 06/12/2024] [Indexed: 06/28/2024] Open
Abstract
Divalent magnesium ions (Mg2+) serve a vital role in defining the structural and catalytic chemistry of a wide array of RNA molecules. The body of structural information on RNA motifs continues to expand and, in turn, the functional importance of Mg2+ is revealed. A combination of prior work on the structural characterization of magnesium binding ligands with inner- and outer-sphere coordination modes, with recorded experimental binding energies for inner- and outer-sphere contacts, demonstrates the relative affinity and thermodynamic hierarchy for these sites. In turn, these can be correlated with cellular concentrations of free available magnesium ions, allowing the prioritization of populating important functional sites and a correlation with physiological function. This paper summarizes some of the key results of that analysis and provides predictive rules for the affinity and role of newly identified Mg binding sites on complex RNA structures. The influence of crystal packing on magnesium binding to RNA motifs, relative to their solution form, is addressed and caveats made.
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Affiliation(s)
- J A Cowan
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
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2
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Hertz LM, White EN, Kuznedelov K, Cheng L, Yu AM, Kakkaramadam R, Severinov K, Chen A, Lucks J. The effect of pseudoknot base pairing on cotranscriptional structural switching of the fluoride riboswitch. Nucleic Acids Res 2024; 52:4466-4482. [PMID: 38567721 PMCID: PMC11077080 DOI: 10.1093/nar/gkae231] [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: 12/04/2023] [Revised: 02/17/2024] [Accepted: 03/20/2024] [Indexed: 04/16/2024] Open
Abstract
A central question in biology is how RNA sequence changes influence dynamic conformational changes during cotranscriptional folding. Here we investigated this question through the study of transcriptional fluoride riboswitches, non-coding RNAs that sense the fluoride anion through the coordinated folding and rearrangement of a pseudoknotted aptamer domain and a downstream intrinsic terminator expression platform. Using a combination of Escherichia coli RNA polymerase in vitro transcription and cellular gene expression assays, we characterized the function of mesophilic and thermophilic fluoride riboswitch variants. We showed that only variants containing the mesophilic pseudoknot function at 37°C. We next systematically varied the pseudoknot sequence and found that a single wobble base pair is critical for function. Characterizing thermophilic variants at 65°C through Thermus aquaticus RNA polymerase in vitro transcription showed the importance of this wobble pair for function even at elevated temperatures. Finally, we performed all-atom molecular dynamics simulations which supported the experimental findings, visualized the RNA structure switching process, and provided insight into the important role of magnesium ions. Together these studies provide deeper insights into the role of riboswitch sequence in influencing folding and function that will be important for understanding of RNA-based gene regulation and for synthetic biology applications.
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Affiliation(s)
- Laura M Hertz
- Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, IL 60208, USA
| | - Elise N White
- Department of Chemistry and the RNA Institute, University at Albany, Albany, NY 12222, USA
| | | | - Luyi Cheng
- Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, IL 60208, USA
| | - Angela M Yu
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA 98195, USA
| | - Rivaan Kakkaramadam
- Department of Chemistry and the RNA Institute, University at Albany, Albany, NY 12222, USA
| | - Konstantin Severinov
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854, USA
| | - Alan Chen
- Department of Chemistry and the RNA Institute, University at Albany, Albany, NY 12222, USA
| | - Julius B Lucks
- Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, IL 60208, USA
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208, USA
- Center for Synthetic Biology, Northwestern University, Evanston, IL 60208, USA
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3
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Fang Z, Pazienza LT, Zhang J, Tam CP, Szostak JW. Catalytic Metal Ion-Substrate Coordination during Nonenzymatic RNA Primer Extension. J Am Chem Soc 2024; 146:10632-10639. [PMID: 38579124 PMCID: PMC11027144 DOI: 10.1021/jacs.4c00323] [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: 01/08/2024] [Revised: 02/22/2024] [Accepted: 03/22/2024] [Indexed: 04/07/2024]
Abstract
Nonenzymatic template-directed RNA copying requires catalysis by divalent metal ions. The primer extension reaction involves the attack of the primer 3'-hydroxyl on the adjacent phosphate of a 5'-5'-imidazolium-bridged dinucleotide substrate. However, the nature of the interaction of the catalytic metal ion with the reaction center remains unclear. To explore the coordination of the catalytic metal ion with the imidazolium-bridged dinucleotide substrate, we examined catalysis by oxophilic and thiophilic metal ions with both diastereomers of phosphorothioate-modified substrates. We show that Mg2+ and Cd2+ exhibit opposite preferences for the two phosphorothioate substrate diastereomers, indicating a stereospecific interaction of the divalent cation with one of the nonbridging phosphorus substituents. High-resolution X-ray crystal structures of the products of primer extension with phosphorothioate substrates reveal the absolute stereochemistry of this interaction and indicate that catalysis by Mg2+ involves inner-sphere coordination with the nonbridging phosphate oxygen in the pro-SP position, while thiophilic cadmium ions interact with sulfur in the same position, as in one of the two phosphorothioate substrates. These results collectively suggest that during nonenzymatic RNA primer extension with a 5'-5'-imidazolium-bridged dinucleotide substrate the interaction of the catalytic Mg2+ ion with the pro-SP oxygen of the reactive phosphate plays a crucial role in the metal-catalyzed SN2(P) reaction.
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Affiliation(s)
- Ziyuan Fang
- Department
of Chemistry, Howard Hughes Medical Institute,
The University of Chicago, Chicago, Illinois 60637, United States
| | - Lydia T. Pazienza
- Department
of Chemistry and Chemical Biology, Harvard
University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
- Department
of Molecular Biology and Center for Computational and Integrative
Biology, Howard Hughes Medical Institute,
Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, United States
| | - Jian Zhang
- Department
of Chemistry, Howard Hughes Medical Institute,
The University of Chicago, Chicago, Illinois 60637, United States
| | - Chun Pong Tam
- Department
of Chemistry and Chemical Biology, Harvard
University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
- Department
of Molecular Biology and Center for Computational and Integrative
Biology, Howard Hughes Medical Institute,
Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, United States
| | - Jack W. Szostak
- Department
of Chemistry, Howard Hughes Medical Institute,
The University of Chicago, Chicago, Illinois 60637, United States
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4
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Sodnikar K, Kaegi R, Christl I, Schroth MH, Sander M. Transport of double-stranded ribonucleic acids (dsRNA) and deoxyribonucleic acids (DNA) in sand and iron oxide-coated sand columns under varying solution chemistries. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2023; 25:2067-2080. [PMID: 37870439 DOI: 10.1039/d3em00294b] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2023]
Abstract
Assessing ecological risks associated with the use of genetically modified RNA interference crops demands an understanding of the fate of crop-released insecticidal double-stranded RNA (dsRNA) molecules in soils. We studied the adsorption of one dsRNA and two double-stranded DNA as model nucleic acids (NAs) during transport through sand- and iron oxide-coated sand (IOCS)-filled columns over a range of solution pH and ionic compositions. Consistent with NA-sand electrostatic repulsion, we observed only slight retention of NAs in sand columns. Conversely, pronounced NA retention in IOCS columns is consistent with strong and irreversible NA adsorption involving electrostatic attraction to and inner-sphere complex formation of NAs with iron oxide coatings. Adsorption of NAs to iron oxides revealed a fast and a slow kinetic adsorption regime, possibly caused by the excluded-area effect. Adsorption of NAs to sand and IOCS increased in the presence of dissolved Mg2+ and with increasing ionic strength, reflecting cation-bridging and screening of repulsive electrostatics, respectively. The co-solute phosphate and a pre-adsorbed dissolved organic matter isolate competitively suppressed dsRNA adsorption to IOCS. Similar adsorption characteristics of dsRNA and similarly sized DNA suggest that existing information on DNA adsorption to soil particles helps in predicting adsorption and fate of dsRNA molecules in soils.
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Affiliation(s)
- Katharina Sodnikar
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zurich, Switzerland.
| | - Ralf Kaegi
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - Iso Christl
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zurich, Switzerland.
| | - Martin Herbert Schroth
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zurich, Switzerland.
| | - Michael Sander
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zurich, Switzerland.
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5
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Hertz LM, White EN, Kuznedelov K, Cheng L, Yu AM, Kakkaramadam R, Severinov K, Chen A, Lucks JB. The Effect of Pseudoknot Base Pairing on Cotranscriptional Structural Switching of the Fluoride Riboswitch. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.05.570056. [PMID: 38106011 PMCID: PMC10723315 DOI: 10.1101/2023.12.05.570056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
A central question in biology is how RNA sequence changes influence dynamic conformational changes during cotranscriptional folding. Here we investigated this question through the study of transcriptional fluoride riboswitches, non-coding RNAs that sense the fluoride anion through the coordinated folding and rearrangement of a pseudoknotted aptamer domain and a downstream intrinsic terminator expression platform. Using a combination of E. coli RNA polymerase in vitro transcription and cellular gene expression assays, we characterized the function of mesophilic and thermophilic fluoride riboswitch variants. We showed that only variants containing the mesophilic pseudoknot function at 37 °C. We next systematically varied the pseudoknot sequence and found that a single wobble base pair is critical for function. Characterizing thermophilic variants at 65 °C through Thermus aquaticus RNA polymerase in vitro transcription showed the importance of this wobble pair for function even at elevated temperatures. Finally, we performed all-atom molecular dynamics simulations which supported the experimental findings, visualized the RNA structure switching process, and provided insight into the important role of magnesium ions. Together these studies provide deeper insights into the role of riboswitch sequence in influencing folding and function that will be important for understanding of RNA-based gene regulation and for synthetic biology applications.
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Affiliation(s)
- Laura M Hertz
- Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, IL 60208, USA
| | - Elise N White
- Department of Chemistry and the RNA Institute, University at Albany, Albany, NY 12222, USA
| | | | - Luyi Cheng
- Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, IL 60208, USA
| | - Angela M Yu
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA 98195, USA
| | - Rivaan Kakkaramadam
- Department of Chemistry and the RNA Institute, University at Albany, Albany, NY 12222, USA
| | - Konstantin Severinov
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854, USA
| | - Alan Chen
- Department of Chemistry and the RNA Institute, University at Albany, Albany, NY 12222, USA
| | - Julius B Lucks
- Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, IL 60208, USA
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208, USA
- Center for Synthetic Biology, Northwestern University, Evanston, IL 60208, USA
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6
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Grille L, Gallego D, Darré L, da Rosa G, Battistini F, Orozco M, Dans PD. The pseudotorsional space of RNA. RNA (NEW YORK, N.Y.) 2023; 29:1896-1909. [PMID: 37793790 PMCID: PMC10653382 DOI: 10.1261/rna.079821.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 09/01/2023] [Indexed: 10/06/2023]
Abstract
The characterization of the conformational landscape of the RNA backbone is rather complex due to the ability of RNA to assume a large variety of conformations. These backbone conformations can be depicted by pseudotorsional angles linking RNA backbone atoms, from which Ramachandran-like plots can be built. We explore here different definitions of these pseudotorsional angles, finding that the most accurate ones are the traditional η (eta) and θ (theta) angles, which represent the relative position of RNA backbone atoms P and C4'. We explore the distribution of η - θ in known experimental structures, comparing the pseudotorsional space generated with structures determined exclusively by one experimental technique. We found that the complete picture only appears when combining data from different sources. The maps provide a quite comprehensive representation of the RNA accessible space, which can be used in RNA-structural predictions. Finally, our results highlight that protein interactions lead to significant changes in the population of the η - θ space, pointing toward the role of induced-fit mechanisms in protein-RNA recognition.
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Affiliation(s)
- Leandro Grille
- Computational Biophysics Group, Department of Biological Sciences, CENUR Litoral Norte, Universidad de la República, 50000 Salto, Uruguay
- Bioinformatics Unit, Institute Pasteur of Montevideo, 11400 Montevideo, Uruguay
| | - Diego Gallego
- Molecular Modelling and Bioinformatics Group, Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Leonardo Darré
- Bioinformatics Unit, Institute Pasteur of Montevideo, 11400 Montevideo, Uruguay
- Molecular Modelling and Bioinformatics Group, Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
| | - Gabriela da Rosa
- Computational Biophysics Group, Department of Biological Sciences, CENUR Litoral Norte, Universidad de la República, 50000 Salto, Uruguay
- Bioinformatics Unit, Institute Pasteur of Montevideo, 11400 Montevideo, Uruguay
| | - Federica Battistini
- Molecular Modelling and Bioinformatics Group, Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Modesto Orozco
- Molecular Modelling and Bioinformatics Group, Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Pablo D Dans
- Computational Biophysics Group, Department of Biological Sciences, CENUR Litoral Norte, Universidad de la República, 50000 Salto, Uruguay
- Bioinformatics Unit, Institute Pasteur of Montevideo, 11400 Montevideo, Uruguay
- Molecular Modelling and Bioinformatics Group, Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
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7
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Vilcapoma J, Aliyeva A, Hayden A, Chandrasekaran AR, Zhou L, Punnoose JA, Yang D, Hansen C, Shiu SCC, Russell A, George KS, Wong WP, Halvorsen K. A non-enzymatic test for SARS-CoV-2 RNA using DNA nanoswitches. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.05.31.23290613. [PMID: 37398235 PMCID: PMC10312858 DOI: 10.1101/2023.05.31.23290613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
The emergence of a highly contagious novel coronavirus in 2019 led to an unprecedented need for large scale diagnostic testing. The associated challenges including reagent shortages, cost, deployment delays, and turnaround time have all highlighted the need for an alternative suite of low-cost tests. Here, we demonstrate a diagnostic test for SARS-CoV-2 RNA that provides direct detection of viral RNA and eliminates the need for costly enzymes. We employ DNA nanoswitches that respond to segments of the viral RNA by a change in shape that is readable by gel electrophoresis. A new multi-targeting approach samples 120 different viral regions to improve the limit of detection and provide robust detection of viral variants. We apply our approach to a cohort of clinical samples, positively identifying a subset of samples with high viral loads. Since our method directly detects multiple regions of viral RNA without amplification, it eliminates the risk of amplicon contamination and renders the method less susceptible to false positives. This new tool can benefit the COVID-19 pandemic and future emerging outbreaks, providing a third option between amplification-based RNA detection and protein antigen detection. Ultimately, we believe this tool can be adapted both for low-resource onsite testing as well as for monitoring viral loads in recovering patients.
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Affiliation(s)
- Javier Vilcapoma
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222
| | - Asmer Aliyeva
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222
| | - Andrew Hayden
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222
| | | | - Lifeng Zhou
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222
| | | | - Darren Yang
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115
| | - Clinton Hansen
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115
| | - Simon Chi-Chin Shiu
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222
| | - Alexis Russell
- Laboratory of Viral Diseases, Wadsworth Center, New York State Department of Health, Albany, NY 12208
| | - Kirsten St. George
- Laboratory of Viral Diseases, Wadsworth Center, New York State Department of Health, Albany, NY 12208
- Department of Biomedical Science, University at Albany, State University of New York, Albany, NY 12208
| | - Wesley P. Wong
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115
| | - Ken Halvorsen
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222
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8
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Lauman R, Kim HJ, Pino LK, Scacchetti A, Xie Y, Robison F, Sidoli S, Bonasio R, Garcia BA. Expanding the Epitranscriptomic RNA Sequencing and Modification Mapping Mass Spectrometry Toolbox with Field Asymmetric Waveform Ion Mobility and Electrochemical Elution Liquid Chromatography. Anal Chem 2023; 95:5187-5195. [PMID: 36916610 PMCID: PMC10190205 DOI: 10.1021/acs.analchem.2c04114] [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] [Indexed: 03/15/2023]
Abstract
Post-transcriptional modifications of RNA strongly influence the RNA structure and function. Recent advances in RNA sequencing and mass spectrometry (MS) methods have identified over 140 of these modifications on a wide variety of RNA species. Most next-generation sequencing approaches can only map one RNA modification at a time, and while MS can assign multiple modifications simultaneously in an unbiased manner, MS cannot accurately catalog and assign RNA modifications in complex biological samples due to limitations in the fragment length and coverage depth. Thus, a facile method to identify novel RNA modifications while simultaneously locating them in the context of their RNA sequences is still lacking. We combined two orthogonal modes of RNA ion separation before MS identification: high-field asymmetric ion mobility separation (FAIMS) and electrochemically modulated liquid chromatography (EMLC). FAIMS RNA MS increases both coverage and throughput, while EMLC LC-MS orthogonally separates RNA molecules of different lengths and charges. The combination of the two methods offers a broadly applicable platform to improve the length and depth of MS-based RNA sequencing while providing contextual access to the analysis of RNA modifications.
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Affiliation(s)
- Richard Lauman
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, USA
- Epigenetic Institute and Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Hee Jong Kim
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, USA
| | - Lindsay K. Pino
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, USA
| | - Alessandro Scacchetti
- Epigenetic Institute and Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Yixuan Xie
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Faith Robison
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Simone Sidoli
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Roberto Bonasio
- Epigenetic Institute and Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Benjamin A. Garcia
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
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9
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Arteaga SJ, Adams MS, Meyer NL, Richardson KE, Hoener S, Znosko BM. Thermodynamic determination of RNA duplex stability in magnesium solutions. Biophys J 2023; 122:565-576. [PMID: 36540026 PMCID: PMC9941723 DOI: 10.1016/j.bpj.2022.12.025] [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: 08/08/2022] [Revised: 12/05/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
The prediction of RNA secondary structure and thermodynamics from sequence relies on free energy minimization and nearest neighbor parameters. Currently, algorithms used to make these predictions are based on parameters from optical melting studies performed in 1 M NaCl. However, many physiological and biochemical buffers containing RNA include much lower concentrations of monovalent cations and the presence of divalent cations. In order to improve these algorithms, thermodynamic data was previously collected for RNA duplexes in solutions containing 71, 121, 221, and 621 mM Na+. From this data, correction factors for free energy (ΔG°37) and melting temperature (Tm) were derived. Despite these newly derived correction factors for sodium, the stabilizing effects of magnesium have been ignored. Here, the same RNA duplexes were melted in solutions containing 0.5, 1.5, 3.0, and 10.0 mM Mg2+ in the absence of monovalent cations. Correction factors for Tm and ΔG°37 were derived to scale the current parameters to a range of magnesium concentrations. The Tm correction factor predicts the melting temperature within 1.2°C, and the ΔG°37 correction factor predicts the free energy within 0.30 kcalmol. These newly derived magnesium correction factors can be incorporated into algorithms that predict RNA secondary structure and stability from sequence.
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Affiliation(s)
| | - Miranda S Adams
- Department of Chemistry, Saint Louis University, Saint Louis, Missouri
| | - Nicole L Meyer
- Department of Chemistry, Saint Louis University, Saint Louis, Missouri
| | | | - Scott Hoener
- Department of Chemistry, Saint Louis University, Saint Louis, Missouri
| | - Brent M Znosko
- Department of Chemistry, Saint Louis University, Saint Louis, Missouri.
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10
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Ali Z, Goyal A, Jhunjhunwala A, Mitra A, Trant JF, Sharma P. Structural and Energetic Features of Base-Base Stacking Contacts in RNA. J Chem Inf Model 2023; 63:655-669. [PMID: 36635230 DOI: 10.1021/acs.jcim.2c01116] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Nucleobase π-π stacking is one of the crucial organizing interactions within three-dimensional (3D) RNA architectures. Characterizing the structural variability of these contacts in RNA crystal structures will help delineate their subtleties and their role in determining function. This analysis of different stacking geometries found in RNA X-ray crystal structures is the largest such survey to date; coupled with quantum-mechanical calculations on typical representatives of each possible stacking arrangement, we determined the distribution of stacking interaction energies. A total of 1,735,481 stacking contacts, spanning 359 of the 384 theoretically possible distinct stacking geometries, were identified. Our analysis reveals preferential occurrences of specific consecutive stacking arrangements in certain regions of RNA architectures. Quantum chemical calculations suggest that 88 of the 359 contacts possess intrinsically stable stacking geometries, whereas the remaining stacks require the RNA backbone or surrounding macromolecular environment to force their formation and maintain their stability. Our systematic analysis of π-π stacks in RNA highlights trends in the occurrence and localization of these noncovalent interactions and may help better understand the structural intricacies of functional RNA-based molecular architectures.
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Affiliation(s)
- Zakir Ali
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh160014, India
| | - Ambika Goyal
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh160014, India
| | - Ayush Jhunjhunwala
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad, Gachibowli, Hyderabad, Telangana500032, India
| | - Abhijit Mitra
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad, Gachibowli, Hyderabad, Telangana500032, India
| | - John F Trant
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, OntarioN9B 3P4, Canada
- Binary Star Research Services, LaSalle, OntarioN9J 3X8, Canada
| | - Purshotam Sharma
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh160014, India
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, OntarioN9B 3P4, Canada
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11
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Torrez RM, Ohi MD, Garner AL. Structural Insights into the Advances and Mechanistic Understanding of Human Dicer. Biochemistry 2023; 62:1-16. [PMID: 36534787 DOI: 10.1021/acs.biochem.2c00570] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The RNase III endoribonuclease Dicer was discovered to be associated with cleavage of double-stranded RNA in 2001. Since then, many advances in our understanding of Dicer function have revealed that the enzyme plays a major role not only in microRNA biology but also in multiple RNA interference-related pathways. Yet, there is still much to be learned regarding Dicer structure-function in relation to how Dicer and Dicer-like enzymes initiate their cleavage reaction and release the desired RNA product. This Perspective describes the latest advances in Dicer structural studies, expands on what we have learned from this data, and outlines key gaps in knowledge that remain to be addressed. More specifically, we focus on human Dicer and highlight the intermediate processing steps where there is a lack of structural data to understand how the enzyme traverses from pre-cleavage to cleavage-competent states. Understanding these details is necessary to model Dicer's function as well as develop more specific microRNA-targeted therapeutics for the treatment of human diseases.
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Affiliation(s)
- Rachel M Torrez
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109, United States.,Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, United States
| | - Melanie D Ohi
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, United States.,Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, Michigan 48109, United States
| | - Amanda L Garner
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109, United States
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12
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Investigation of the ionic conditions in SiRNA-mediated delivery through its carriers in the cell membrane: a molecular dynamic simulation. Sci Rep 2022; 12:17520. [PMID: 36266467 PMCID: PMC9582388 DOI: 10.1038/s41598-022-22509-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 10/17/2022] [Indexed: 01/12/2023] Open
Abstract
SiRNA is a new generation of drug molecules and a new approach for treating a variety of diseases such as cancer and viral infections. SiRNA delivery to cells and translocation into cytoplasm are the main challenges in the clinical application of siRNA. Lipid carriers are one of the most successful carriers for siRNA delivery. In this study, we investigated the interaction of siRNA with a zwitterionic bilayer and how ion concentration and lipid conjugation can affect it. The divalent cation such as Mg2+ ions could promote the siRNA adsorption on the bilayer surface. The cation ions can bind to the head groups of lipids and the grooves of siRNA molecules and form bridges between the siRNA and bilayer surface. Our findings demonstrated the bridges formed by divalent ions could facilitate the attachment of siRNA to the membrane surface. We showed that the divalent cations can regulate the bridging-driven membrane attachment and it seems the result of this modulation can be used for designing biomimetic devices. In the following, we examined the effect of cations on the interaction between siRNA modified by cholesterol and the membrane surface. Our MD simulations showed that in the presence of Mg2+, the electrostatic and vdW energy between the membrane and siRNA were higher compared to those in the presence of NA+. We showed that the electrostatic interaction between membrane and siRNA cannot be facilitated only by cholesterol conjugated. Indeed, cations are essential to create coulomb repulsion and enable membrane attachment. This study provides important insight into liposome carriers for siRNA delivery and could help us in the development of siRNA-based therapeutics. Due to the coronavirus pandemic outbreak, these results may shed light on the new approach for treating these diseases and their molecular details.
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13
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Martinez-Monge A, Pastor I, Bustamante C, Manosas M, Ritort F. Measurement of the specific and non-specific binding energies of Mg 2+ to RNA. Biophys J 2022; 121:3010-3022. [PMID: 35864738 PMCID: PMC9463699 DOI: 10.1016/j.bpj.2022.07.020] [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] [Indexed: 11/02/2022] Open
Abstract
Determining the non-specific and specific electrostatic contributions of magnesium binding to RNA is a challenging problem. We introduce a single-molecule method based on measuring the folding energy of a native RNA in magnesium and at its equivalent sodium concentration. The latter is defined so that the folding energy in sodium equals the non-specific electrostatic contribution in magnesium. The sodium equivalent can be estimated according to the empirical 100/1 rule (1 M NaCl is equivalent to 10 mM MgCl2), which is a good approximation for most RNAs. The method is applied to an RNA three-way junction (3WJ) that contains specific Mg2+ binding sites and misfolds into a double hairpin structure without binding sites. We mechanically pull the RNA with optical tweezers and use fluctuation theorems to determine the folding energies of the native and misfolded structures in magnesium (10 mM MgCl2) and at the equivalent sodium condition (1 M NaCl). While the free energies of the misfolded structure are equal in magnesium and sodium, they are not for the native structure, the difference being due to the specific binding energy of magnesium to the 3WJ, which equals ΔG≃ 10 kcal/mol. Besides stabilizing the 3WJ, Mg2+ also kinetically rescues it from the misfolded structure over timescales of tens of seconds in a force-dependent manner. The method should generally be applicable to determine the specific binding energies of divalent cations to other tertiary RNAs.
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Affiliation(s)
- A Martinez-Monge
- Small Biosystems Lab, Departament de Física de la Matèria Condensada, Facultat de Física, Universitat de Barcelona, Carrer de Martí i Franquès, 1, 08028 Barcelona, Spain
| | - Isabel Pastor
- Small Biosystems Lab, Departament de Física de la Matèria Condensada, Facultat de Física, Universitat de Barcelona, Carrer de Martí i Franquès, 1, 08028 Barcelona, Spain; Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, 08028 Barcelona, Spain
| | - Carlos Bustamante
- Departments of Chemistry, Physics and Molecular and Cell Biology, University of California Berkeley, Berkeley, California; Howard Hughes Medical Institute University of California Berkeley, Berkeley, California; Kavli Energy Nanosciences Institute, University of California Berkeley, Berkeley, California
| | - Maria Manosas
- Small Biosystems Lab, Departament de Física de la Matèria Condensada, Facultat de Física, Universitat de Barcelona, Carrer de Martí i Franquès, 1, 08028 Barcelona, Spain; Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, 08028 Barcelona, Spain.
| | - Felix Ritort
- Small Biosystems Lab, Departament de Física de la Matèria Condensada, Facultat de Física, Universitat de Barcelona, Carrer de Martí i Franquès, 1, 08028 Barcelona, Spain; Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, 08028 Barcelona, Spain.
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14
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le Goff S, Godin JP, Albalat E, Nieves JMR, Balter V. Magnesium stable isotope composition, but not concentration, responds to obesity and early insulin-resistant conditions in minipig. Sci Rep 2022; 12:10941. [PMID: 35768618 PMCID: PMC9243132 DOI: 10.1038/s41598-022-14825-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 06/13/2022] [Indexed: 11/29/2022] Open
Abstract
Hypomagnesemia is frequently associated with type 2 diabetes and generally correlates with unfavorable disease progression, but the magnesium status in pre-diabetic conditions remains unclear. Here, the magnesium metabolism is scrutinized in a minipig model of obesity and insulin resistance by measuring variations of the metallome—the set of inorganic elements—and the magnesium stable isotope composition in six organs of lean and obese minipigs raised on normal and Western-type diet, respectively. We found that metallomic variations are most generally insensitive to lean or obese phenotypes. The magnesium stable isotope composition of plasma, liver, kidney, and heart in lean minipigs are significantly heavier than in obese minipigs. For both lean and obese minipigs, the magnesium isotope composition of plasma and liver were negatively correlated to clinical phenotypes and plasma lipoproteins concentration as well as positively correlated to hyperinsulinemic-euglycemic clamp output. Because the magnesium isotope composition was not associated to insulin secretion, our results suggest that it is rather sensitive to whole body insulin sensitivity, opening perspectives to better comprehend the onset of insulin-resistant diabetic conditions.
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Affiliation(s)
- Samuel le Goff
- Laboratoire de Géologie de Lyon, ENS de Lyon, Université de Lyon, CNRS, Lyon, France
| | - Jean-Philippe Godin
- Nestlé Research, Institute of Food Safety and Analytical Sciences, Lausanne, Switzerland
| | - Emmanuelle Albalat
- Laboratoire de Géologie de Lyon, ENS de Lyon, Université de Lyon, CNRS, Lyon, France
| | | | - Vincent Balter
- Laboratoire de Géologie de Lyon, ENS de Lyon, Université de Lyon, CNRS, Lyon, France.
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15
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16
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A novel aptamer-based small RNA delivery platform and its application to cancer therapy. Genes Dis 2022. [DOI: 10.1016/j.gendis.2022.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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17
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Kumar S, Reddy G. TPP Riboswitch Populates Holo-Form-like Structure Even in the Absence of Cognate Ligand at High Mg 2+ Concentration. J Phys Chem B 2022; 126:2369-2381. [PMID: 35298161 DOI: 10.1021/acs.jpcb.1c10794] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Riboswitches are noncoding RNA that regulate gene expression by folding into specific three-dimensional structures (holo-form) upon binding by their cognate ligand in the presence of Mg2+. Riboswitch functioning is also hypothesized to be under kinetic control requiring large cognate ligand concentrations. We ask the question under thermodynamic conditions, can the riboswitches populate structures similar to the holo-form only in the presence of Mg2+ and absence of cognate ligand binding. We addressed this question using thiamine pyrophosphate (TPP) riboswitch as a model system and computer simulations using a coarse-grained model for RNA. The folding free energy surface (FES) shows that with the initial increase in Mg2+ concentration ([Mg2+]), the aptamer domain (AD) of TPP riboswitch undergoes a barrierless collapse in its dimensions. On further increase in [Mg2+], intermediates separated by barriers appear on the FES, and one of the intermediates has a TPP ligand-binding competent structure. We show that site-specific binding of the Mg2+ aids in the formation of tertiary contacts. For [Mg2+] greater than physiological concentration, AD folds into a structure similar to the crystal structure of the TPP holo-form even in the absence of the TPP ligand. The folding kinetics shows that TPP AD populates an intermediate due to the misalignment of two arms present in the structure, which acts as a kinetic trap, leading to larger folding timescales. The predictions of the intermediate structures from the simulations are amenable for experimental verification.
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Affiliation(s)
- Sunil Kumar
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Govardhan Reddy
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru, Karnataka 560012, India
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18
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Huang PJJ, Liu J. Sensing Metal Ions with Phosphorothioate-Modified DNAzymes. Methods Mol Biol 2022; 2439:277-289. [PMID: 35226327 DOI: 10.1007/978-1-0716-2047-2_17] [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] [Indexed: 06/14/2023]
Abstract
Phosphorothioate (PS) modification refers to replacing one of the nonbridging oxygen atoms in nucleic acids with sulfur. PS modifications can be easily introduced during solid-phase DNA synthesis. It has been extensively used in ribozyme and DNAzyme research to achieve a bioinorganic understanding of metal binding, bioanalytical applications of metal detection, and chemical biology of DNA modification. It allows for the access of new chemistry, not available to natural DNA. Since each PS modification is accompanied by the production of a chiral phosphorus center, a key technical challenge is to separate the two diastereomers called Rp and Sp. In this chapter, we describe our methods of HPLC-based separation followed by ligation to generate a long and fluorescently modified DNAzyme substrate. Subsequently, the use of the modified substrate for activity assay to understand metal binding and for metal ion detection is also described.
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Affiliation(s)
- Po-Jung Jimmy Huang
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON, Canada
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON, Canada.
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19
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Fang X, Gallego J, Wang YX. Deriving RNA topological structure from SAXS. Methods Enzymol 2022; 677:479-529. [DOI: 10.1016/bs.mie.2022.08.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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20
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Meshkin H, Zhu F. Toward Convergence in Free Energy Calculations for Protein Conformational Changes: A Case Study on the Thin Gate of Mhp1 Transporter. J Chem Theory Comput 2021; 17:6583-6596. [PMID: 34523931 DOI: 10.1021/acs.jctc.1c00585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
It has been challenging to obtain reliable free energies for protein conformational changes from all-atom molecular dynamics simulations, despite the availability of many enhanced sampling techniques. To alleviate the difficulties associated with the enormous complexity of the conformational space, here we propose a few practical strategies for such calculations, including (1) a stringent method to examine convergence by comparing independent simulations starting from different initial coordinates, (2) adoption of multistep schemes in which the complete conformational change consists of multiple transition steps, each sampled using a distinct reaction coordinate, and (3) application of boundary restraints to simplify the conformational space. We demonstrate these strategies on the conformational changes between the outward-facing and outward-occluded states of the Mhp1 membrane transporter, obtaining the equilibrium thermodynamics of the relevant metastable states, the kinetic rates between these states, and the reactive trajectories that reveal the atomic details of spontaneous transitions. Our approaches thus promise convergent and reliable calculations to examine intuition-based hypotheses and to eventually elucidate the underlying molecular mechanisms of reversible conformational changes in complex protein systems.
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Affiliation(s)
- Hamed Meshkin
- Department of Physics, Indiana University Purdue University Indianapolis, 402 N. Blackford Street, Indianapolis, Indiana 46202, United States
| | - Fangqiang Zhu
- Department of Physics, Indiana University Purdue University Indianapolis, 402 N. Blackford Street, Indianapolis, Indiana 46202, United States
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21
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Jahmidi-Azizi N, Gault S, Cockell CS, Oliva R, Winter R. Ions in the Deep Subsurface of Earth, Mars, and Icy Moons: Their Effects in Combination with Temperature and Pressure on tRNA-Ligand Binding. Int J Mol Sci 2021; 22:ijms221910861. [PMID: 34639202 PMCID: PMC8509373 DOI: 10.3390/ijms221910861] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/03/2021] [Accepted: 10/06/2021] [Indexed: 01/12/2023] Open
Abstract
The interactions of ligands with nucleic acids are central to numerous reactions in the biological cell. How such reactions are affected by harsh environmental conditions such as low temperatures, high pressures, and high concentrations of destructive ions is still largely unknown. To elucidate the ions’ role in shaping habitability in extraterrestrial environments and the deep subsurface of Earth with respect to fundamental biochemical processes, we investigated the effect of selected salts (MgCl2, MgSO4, and Mg(ClO4)2) and high hydrostatic pressure (relevant for the subsurface of that planet) on the complex formation between tRNA and the ligand ThT. The results show that Mg2+ salts reduce the binding tendency of ThT to tRNA. This effect is largely due to the interaction of ThT with the salt anions, which leads to a strong decrease in the activity of the ligand. However, at mM concentrations, binding is still favored. The ions alter the thermodynamics of binding, rendering complex formation that is more entropy driven. Remarkably, the pressure favors ligand binding regardless of the type of salt. Although the binding constant is reduced, the harsh conditions in the subsurface of Earth, Mars, and icy moons do not necessarily preclude nucleic acid–ligand interactions of the type studied here.
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Affiliation(s)
- Nisrine Jahmidi-Azizi
- Physical Chemistry I-Biophysical Chemistry, Department of Chemistry and Chemical Biology, TU Dortmund University, 44227 Dortmund, Germany;
| | - Stewart Gault
- UK Centre for Astrobiology, SUPA School of Physics and Astronomy, University of Edinburgh, James Clerk Maxwell Building, Edinburgh EH9 3FD, UK; (S.G.); (C.S.C.)
| | - Charles S. Cockell
- UK Centre for Astrobiology, SUPA School of Physics and Astronomy, University of Edinburgh, James Clerk Maxwell Building, Edinburgh EH9 3FD, UK; (S.G.); (C.S.C.)
| | - Rosario Oliva
- Physical Chemistry I-Biophysical Chemistry, Department of Chemistry and Chemical Biology, TU Dortmund University, 44227 Dortmund, Germany;
- Correspondence: (R.O.); (R.W.)
| | - Roland Winter
- Physical Chemistry I-Biophysical Chemistry, Department of Chemistry and Chemical Biology, TU Dortmund University, 44227 Dortmund, Germany;
- Correspondence: (R.O.); (R.W.)
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22
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Marathe IA, Lai SM, Zahurancik WJ, Poirier MG, Wysocki VH, Gopalan V. Protein cofactors and substrate influence Mg2+-dependent structural changes in the catalytic RNA of archaeal RNase P. Nucleic Acids Res 2021; 49:9444-9458. [PMID: 34387688 PMCID: PMC8450104 DOI: 10.1093/nar/gkab655] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/02/2021] [Accepted: 07/23/2021] [Indexed: 01/07/2023] Open
Abstract
The ribonucleoprotein (RNP) form of archaeal RNase P comprises one catalytic RNA and five protein cofactors. To catalyze Mg2+-dependent cleavage of the 5′ leader from pre-tRNAs, the catalytic (C) and specificity (S) domains of the RNase P RNA (RPR) cooperate to recognize different parts of the pre-tRNA. While ∼250–500 mM Mg2+ renders the archaeal RPR active without RNase P proteins (RPPs), addition of all RPPs lowers the Mg2+ requirement to ∼10–20 mM and improves the rate and fidelity of cleavage. To understand the Mg2+- and RPP-dependent structural changes that increase activity, we used pre-tRNA cleavage and ensemble FRET assays to characterize inter-domain interactions in Pyrococcus furiosus (Pfu) RPR, either alone or with RPPs ± pre-tRNA. Following splint ligation to doubly label the RPR (Cy3-RPRC domain and Cy5-RPRS domain), we used native mass spectrometry to verify the final product. We found that FRET correlates closely with activity, the Pfu RPR and RNase P holoenzyme (RPR + 5 RPPs) traverse different Mg2+-dependent paths to converge on similar functional states, and binding of the pre-tRNA by the holoenzyme influences Mg2+ cooperativity. Our findings highlight how Mg2+ and proteins in multi-subunit RNPs together favor RNA conformations in a dynamic ensemble for functional gains.
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Affiliation(s)
- Ila A Marathe
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Stella M Lai
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Resource for Native Mass Spectrometry-Guided Structural Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Walter J Zahurancik
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Michael G Poirier
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Department of Physics, The Ohio State University, Columbus, OH 43210, USA
| | - Vicki H Wysocki
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Resource for Native Mass Spectrometry-Guided Structural Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Venkat Gopalan
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
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23
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Yong XE, Palur VR, Anand GS, Wohland T, Sharma KK. Dengue virus 2 capsid protein chaperones the strand displacement of 5'-3' cyclization sequences. Nucleic Acids Res 2021; 49:5832-5844. [PMID: 34037793 PMCID: PMC8191770 DOI: 10.1093/nar/gkab379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 04/21/2021] [Accepted: 04/28/2021] [Indexed: 01/02/2023] Open
Abstract
By virtue of its chaperone activity, the capsid protein of dengue virus strain 2 (DENV2C) promotes nucleic acid structural rearrangements. However, the role of DENV2C during the interaction of RNA elements involved in stabilizing the 5′-3′ panhandle structure of DENV RNA is still unclear. Therefore, we determined how DENV2C affects structural functionality of the capsid-coding region hairpin element (cHP) during annealing and strand displacement of the 9-nt cyclization sequence (5CS) and its complementary 3CS. cHP has two distinct functions: a role in translation start codon selection and a role in RNA synthesis. Our results showed that cHP impedes annealing between 5CS and 3CS. Although DENV2C does not modulate structural functionality of cHP, it accelerates annealing and specifically promotes strand displacement of 3CS during 5′-3′ panhandle formation. Furthermore, DENV2C exerts its chaperone activity by favouring one of the active conformations of cHP. Based on our results, we propose mechanisms for annealing and strand displacement involving cHP. Thus, our results provide mechanistic insights into how DENV2C regulates RNA synthesis by modulating essential RNA elements in the capsid-coding region, that in turn allow for DENV replication.
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Affiliation(s)
- Xin Ee Yong
- NUS Graduate School Integrative Sciences and Engineering Programme, National University of Singapore, 21 Lower Kent Ridge Road, Singapore 119077, Singapore.,Centre for Bioimaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117557, Singapore
| | - V Raghuvamsi Palur
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
| | - Ganesh S Anand
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
| | - Thorsten Wohland
- Centre for Bioimaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117557, Singapore.,Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
| | - Kamal K Sharma
- Centre for Bioimaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117557, Singapore.,Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
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24
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Sarkar B, Ishii K, Tahara T. Microsecond Folding of preQ 1 Riboswitch and Its Biological Significance Revealed by Two-Dimensional Fluorescence Lifetime Correlation Spectroscopy. J Am Chem Soc 2021; 143:7968-7978. [PMID: 34013733 DOI: 10.1021/jacs.1c01077] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Riboswitches are regulatory elements of bacterial mRNA which function with conformational switching upon binding of specific cellular metabolites. In particular, transcriptional riboswitches regulate gene expression kinetically through the conformational change of the aptamer domain. In this study, we investigate the conformational dynamics and ligand binding mechanisms of the aptamer domain of a transcriptional prequeuosine (preQ1) riboswitch from Bacillus subtilis using two-dimensional fluorescence lifetime correlation spectroscopy (2D FLCS) with microsecond time resolution. The obtained time-resolved single-molecule data indicate that the aptamer domain undergoes folding/unfolding including three forms, which are attributed to hairpin (O), pseudoknot-like (pF), and H-type pseudoknot (fF) structures. It is found that a cofactor, Mg2+, binds only to the fF form with the conformational selection mechanism. In contrast, it is indicated that the ligand, preQ1, binds to the O form with the induced-fit mechanism and significantly accelerates the microsecond O → pF folding process. It is also shown that the binding with preQ1 substantially stabilizes the fF form that is generated from the pF form with a long time constant (>10 ms). Combining these results with the results of a former smFRET study on the slower time scale, we obtain an overall picture of the folding/unfolding dynamics of the aptamer domain as well as its energy landscape. On the basis of the picture obtained, we discuss the significance of the microsecond folding/unfolding of the aptamer domain for biological function of the riboswitch and propose the molecular mechanism of the gene expression controlled by the structural dynamics of the aptamer domain.
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Affiliation(s)
- Bidyut Sarkar
- Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan
| | - Kunihiko Ishii
- Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan.,Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics (RAP), 2-1 Hirosawa, Wako 351-0198, Japan
| | - Tahei Tahara
- Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan.,Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics (RAP), 2-1 Hirosawa, Wako 351-0198, Japan
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25
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Sodnikar K, Parker KM, Stump SR, ThomasArrigo LK, Sander M. Adsorption of double-stranded ribonucleic acids (dsRNA) to iron (oxyhydr-)oxide surfaces: comparative analysis of model dsRNA molecules and deoxyribonucleic acids (DNA). ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2021; 23:605-620. [PMID: 33723564 DOI: 10.1039/d1em00010a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Double-stranded ribonucleic acid (dsRNA) molecules are novel plant-incorporated protectants expressed in genetically modified RNA interference (RNAi) crops. Ecological risk assessment (ERA) of RNAi crops requires a heretofore-missing detailed understanding of dsRNA adsorption in soils, a key fate process. Herein, we systematically study the adsorption of a model dsRNA molecule and of two double-stranded deoxyribonucleic acid (DNA) molecules of varying lengths to three soil iron (oxyhydr-)oxides - goethite, lepidocrocite, and hematite - over a range of solution pH (4.5-10), ionic strength (I = 10-100 mM NaCl) and composition (0.5, 1, and 3 mM MgCl2) and in the absence and presence of phosphate (0.05-5 mM) as co-adsorbate. We hypothesized comparable adsorption characteristics of dsRNA and DNA based on their structural similarities. Consistently, the three nucleic acids (NAs) showed high adsorption affinities to the iron (oxyhydr-)oxides with decreasing adsorption in the order goethite, lepidocrocite, and hematite, likely reflecting a decrease in the hydroxyl group density and positive charges of the oxide surfaces in the same order. NA adsorption also decreased with increasing solution pH, consistent with weakening of NA electrostatic attraction to and inner-sphere complex formation with the iron (oxyhydr-)oxides surfaces as pH increased. Adsorbed NA concentrations increased with increasing I and in the presence of Mg2+, consistent with adsorbed NA molecules adopting more compact conformations. Strong NA-phosphate adsorption competition demonstrates that co-adsorbates need consideration in assessing dsRNA fate in soils. Comparable adsorption characteristics of dsRNA and DNA molecules to iron (oxyhydr-)oxides imply that information on DNA adsorption to soil particle surfaces can inform dsRNA ERA.
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Affiliation(s)
- Katharina Sodnikar
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, DUSYS, IBP, Universitätsstrasse 16, CHN H50.3, 8092 Zurich, Switzerland.
| | - Kimberly M Parker
- Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, USA
| | - Simona R Stump
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, DUSYS, IBP, Universitätsstrasse 16, CHN H50.3, 8092 Zurich, Switzerland.
| | - Laurel K ThomasArrigo
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, DUSYS, IBP, Universitätsstrasse 16, CHN H50.3, 8092 Zurich, Switzerland.
| | - Michael Sander
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, DUSYS, IBP, Universitätsstrasse 16, CHN H50.3, 8092 Zurich, Switzerland.
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26
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Effects of dietary magnesium supplementation on growth, feed utilization, nucleic acid ratio and antioxidant status of fingerling Heteropneustes fossilis. Anim Feed Sci Technol 2021. [DOI: 10.1016/j.anifeedsci.2021.114819] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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27
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Saran R, Huang Z, Liu J. Phosphorothioate nucleic acids for probing metal binding, biosensing and nanotechnology. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2020.213624] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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28
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Kleczkowski LA, Igamberdiev AU. Magnesium Signaling in Plants. Int J Mol Sci 2021; 22:1159. [PMID: 33503839 PMCID: PMC7865908 DOI: 10.3390/ijms22031159] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 01/16/2021] [Accepted: 01/19/2021] [Indexed: 01/02/2023] Open
Abstract
Free magnesium (Mg2+) is a signal of the adenylate (ATP+ADP+AMP) status in the cells. It results from the equilibrium of adenylate kinase (AK), which uses Mg-chelated and Mg-free adenylates as substrates in both directions of its reaction. The AK-mediated primary control of intracellular [Mg2+] is finely interwoven with the operation of membrane-bound adenylate- and Mg2+-translocators, which in a given compartment control the supply of free adenylates and Mg2+ for the AK-mediated equilibration. As a result, [Mg2+] itself varies both between and within the compartments, depending on their energetic status and environmental clues. Other key nucleotide-utilizing/producing enzymes (e.g., nucleoside diphosphate kinase) may also be involved in fine-tuning of the intracellular [Mg2+]. Changes in [Mg2+] regulate activities of myriads of Mg-utilizing/requiring enzymes, affecting metabolism under both normal and stress conditions, and impacting photosynthetic performance, respiration, phloem loading and other processes. In compartments controlled by AK equilibrium (cytosol, chloroplasts, mitochondria, nucleus), the intracellular [Mg2+] can be calculated from total adenylate contents, based on the dependence of the apparent equilibrium constant of AK on [Mg2+]. Magnesium signaling, reflecting cellular adenylate status, is likely widespread in all eukaryotic and prokaryotic organisms, due simply to the omnipresent nature of AK and to its involvement in adenylate equilibration.
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Affiliation(s)
- Leszek A. Kleczkowski
- Department of Plant Physiology, Umeå Plant Science Centre, University of Umeå, 901 87 Umeå, Sweden
| | - Abir U. Igamberdiev
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL A1B3X9, Canada;
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Daems E, Dewaele D, Barylyuk K, De Wael K, Sobott F. Aptamer-ligand recognition studied by native ion mobility-mass spectrometry. Talanta 2020; 224:121917. [PMID: 33379118 DOI: 10.1016/j.talanta.2020.121917] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 11/19/2020] [Accepted: 11/21/2020] [Indexed: 12/31/2022]
Abstract
The range of applications for aptamers, small oligonucleotide-based receptors binding to their targets with high specificity and affinity, has been steadily expanding. Our understanding of the mechanisms governing aptamer-ligand recognition and binding is however lagging, stymieing the progress in the rational design of new aptamers and optimization of the known ones. Here we demonstrate the capabilities and limitations of native ion mobility-mass spectrometry for the analysis of their higher-order structure and non-covalent interactions. A set of related cocaine-binding aptamers, displaying a range of folding properties and ligand binding affinities, was used as a case study in both positive and negative electrospray ionization modes. Using carefully controlled experimental conditions, we probed their conformational behavior and interactions with the high-affinity ligand quinine as a surrogate for cocaine. The ratios of bound and unbound aptamers in the mass spectra were used to rank them according to their apparent quinine-binding affinity, qualitatively matching the published ranking order. The arrival time differences between the free aptamer and aptamer-quinine complexes were consistent with a small ligand-induced conformational change, and found to inversely correlate with the affinity of binding. This mass spectrometry-based approach provides a fast and convenient way to study the molecular basis of aptamer-ligand recognition.
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Affiliation(s)
- Elise Daems
- BAMS Research Group, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerp, Belgium; AXES Research Group, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerp, Belgium
| | - Debbie Dewaele
- BAMS Research Group, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerp, Belgium
| | - Konstantin Barylyuk
- BAMS Research Group, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerp, Belgium
| | - Karolien De Wael
- AXES Research Group, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerp, Belgium
| | - Frank Sobott
- BAMS Research Group, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerp, Belgium; Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK; School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK.
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30
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Niu X, Liu Q, Xu Z, Chen Z, Xu L, Xu L, Li J, Fang X. Molecular mechanisms underlying the extreme mechanical anisotropy of the flaviviral exoribonuclease-resistant RNAs (xrRNAs). Nat Commun 2020; 11:5496. [PMID: 33127896 PMCID: PMC7603331 DOI: 10.1038/s41467-020-19260-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 10/07/2020] [Indexed: 02/06/2023] Open
Abstract
Mechanical anisotropy is an essential property for many biomolecules to assume their structures, functions and applications, however, the mechanisms for their direction-dependent mechanical responses remain elusive. Herein, by using a single-molecule nanopore sensing technique, we explore the mechanisms of directional mechanical stability of the xrRNA1 RNA from ZIKA virus (ZIKV), which forms a complex ring-like architecture. We reveal extreme mechanical anisotropy in ZIKV xrRNA1 which highly depends on Mg2+ and the key tertiary interactions. The absence of Mg2+ and disruption of the key tertiary interactions strongly affect the structural integrity and attenuate mechanical anisotropy. The significance of ring structures in RNA mechanical anisotropy is further supported by steered molecular dynamics simulations in combination with force distribution analysis. We anticipate the ring structures can be used as key elements to build RNA-based nanostructures with controllable mechanical anisotropy for biomaterial and biomedical applications.
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Affiliation(s)
- Xiaolin Niu
- Beijing Advanced Innovation Center for Structfural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Qiuhan Liu
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Zhonghe Xu
- Beijing Advanced Innovation Center for Structfural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Zhifeng Chen
- Beijing Advanced Innovation Center for Structfural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Linghui Xu
- Beijing Advanced Innovation Center for Structfural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Lilei Xu
- Beijing Advanced Innovation Center for Structfural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jinghong Li
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, China.
| | - Xianyang Fang
- Beijing Advanced Innovation Center for Structfural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
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García-Castaño A, Madariaga L, Antón-Gamero M, Mejia N, Ponce J, Gómez-Conde S, Pérez de Nanclares G, De la Hoz AB, Martínez R, Saso L, Martínez de LaPiscina I, Urrutia I, Velasco O, Aguayo A, Castaño L, Gaztambide S. Novel variant in the CNNM2 gene associated with dominant hypomagnesemia. PLoS One 2020; 15:e0239965. [PMID: 32997713 PMCID: PMC7527205 DOI: 10.1371/journal.pone.0239965] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 09/16/2020] [Indexed: 12/16/2022] Open
Abstract
The maintenance of magnesium (Mg2+) homeostasis is essential for human life. The Cystathionine-β-synthase (CBS)-pair domain divalent metal cation transport mediators (CNNMs) have been described to be involved in maintaining Mg2+ homeostasis. Among these CNNMs, CNNM2 is expressed in the basolateral membrane of the kidney tubules where it is involved in Mg2+ reabsorption. A total of four patients, two of them with a suspected disorder of calcium metabolism, and two patients with a clinical diagnosis of primary tubulopathy were screened for mutations by Next-Generation Sequencing (NGS). We found one novel likely pathogenic variant in the heterozygous state (c.2384C>A; p.(Ser795*)) in the CNNM2 gene in a family with a suspected disorder of calcium metabolism. In this family, hypomagnesemia was indirectly discovered. Moreover, we observed three novel variants of uncertain significance in heterozygous state in the other three patients (c.557G>C; p.(Ser186Thr), c.778A>T; p.(Ile260Phe), and c.1003G>A; p.(Asp335Asn)). Our study shows the utility of Next-Generation Sequencing in unravelling the genetic origin of rare diseases. In clinical practice, serum Mg2+ should be determined in calcium and PTH-related disorders.
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Affiliation(s)
| | - Leire Madariaga
- Paediatric Nephrology Department, Biocruces Bizkaia Health Research Institute, Hospital Universitario Cruces, CIBERDEM, CIBERER, University of the Basque Country (UPV-EHU), Bizkaia, Spain
| | | | - Natalia Mejia
- Faculty of Medicine, University of Los Andes, Bogotá, Colombia
| | - Jenny Ponce
- Paediatric Department, Hospital Nacional Docente Madre-Niño San Bartolomé, Lima, Peru
| | | | - Gustavo Pérez de Nanclares
- Biocruces Bizkaia Health Research Institute, Hospital Universitario Cruces, CIBERDEM, CIBERER, Bizkaia, Spain
| | | | - Rosa Martínez
- Biocruces Bizkaia Health Research Institute, CIBERDEM, CIBERER, Bizkaia, Spain
| | - Laura Saso
- Biocruces Bizkaia Health Research Institute, Bizkaia, Spain
| | | | - Inés Urrutia
- Biocruces Bizkaia Health Research Institute, CIBERDEM, CIBERER, Bizkaia, Spain
| | - Olaia Velasco
- Biocruces Bizkaia Health Research Institute, Bizkaia, Spain
| | - Aníbal Aguayo
- Biocruces Bizkaia Health Research Institute, Hospital Universitario Cruces, CIBERDEM, CIBERER, Bizkaia, Spain
| | - Luis Castaño
- Endocrinology and Nutrition Department, Biocruces Bizkaia Health Research Institute, Hospital Universitario Cruces, CIBERDEM, CIBERER, University of the Basque Country (UPV-EHU), Bizkaia, Spain
| | - Sonia Gaztambide
- Endocrinology and Nutrition Department, Biocruces Bizkaia Health Research Institute, Hospital Universitario Cruces, CIBERDEM, CIBERER, University of the Basque Country (UPV-EHU), Bizkaia, Spain
- * E-mail:
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Kabir MT, Uddin MS, Zaman S, Begum Y, Ashraf GM, Bin-Jumah MN, Bungau SG, Mousa SA, Abdel-Daim MM. Molecular Mechanisms of Metal Toxicity in the Pathogenesis of Alzheimer’s Disease. Mol Neurobiol 2020; 58:1-20. [DOI: 10.1007/s12035-020-02096-w] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 08/25/2020] [Indexed: 12/24/2022]
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Han H, Xu B, Zeng W, Zhou J. Regulating the biosynthesis of pyridoxal 5'-phosphate with riboswitch to enhance L-DOPA production by Escherichia coli whole-cell biotransformation. J Biotechnol 2020; 321:68-77. [DOI: 10.1016/j.jbiotec.2020.05.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 05/17/2020] [Accepted: 05/18/2020] [Indexed: 02/06/2023]
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Matsarskaia O, Roosen‐Runge F, Schreiber F. Multivalent ions and biomolecules: Attempting a comprehensive perspective. Chemphyschem 2020; 21:1742-1767. [PMID: 32406605 PMCID: PMC7496725 DOI: 10.1002/cphc.202000162] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 05/13/2020] [Indexed: 12/13/2022]
Abstract
Ions are ubiquitous in nature. They play a key role for many biological processes on the molecular scale, from molecular interactions, to mechanical properties, to folding, to self-organisation and assembly, to reaction equilibria, to signalling, to energy and material transport, to recognition etc. Going beyond monovalent ions to multivalent ions, the effects of the ions are frequently not only stronger (due to the obviously higher charge), but qualitatively different. A typical example is the process of binding of multivalent ions, such as Ca2+ , to a macromolecule and the consequences of this ion binding such as compaction, collapse, potential charge inversion and precipitation of the macromolecule. Here we review these effects and phenomena induced by multivalent ions for biological (macro)molecules, from the "atomistic/molecular" local picture of (potentially specific) interactions to the more global picture of phase behaviour including, e. g., crystallisation, phase separation, oligomerisation etc. Rather than attempting an encyclopedic list of systems, we rather aim for an embracing discussion using typical case studies. We try to cover predominantly three main classes: proteins, nucleic acids, and amphiphilic molecules including interface effects. We do not cover in detail, but make some comparisons to, ion channels, colloidal systems, and synthetic polymers. While there are obvious differences in the behaviour of, and the relevance of multivalent ions for, the three main classes of systems, we also point out analogies. Our attempt of a comprehensive discussion is guided by the idea that there are not only important differences and specific phenomena with regard to the effects of multivalent ions on the main systems, but also important similarities. We hope to bridge physico-chemical mechanisms, concepts of soft matter, and biological observations and connect the different communities further.
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Affiliation(s)
| | - Felix Roosen‐Runge
- Department of Biomedical Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Faculty of Health and SocietyMalmö UniversitySweden
- Division of Physical ChemistryLund UniversitySweden
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The Coordination Chemistry of Bio-Relevant Ligands and Their Magnesium Complexes. Molecules 2020; 25:molecules25143172. [PMID: 32664540 PMCID: PMC7397051 DOI: 10.3390/molecules25143172] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/07/2020] [Accepted: 07/08/2020] [Indexed: 12/15/2022] Open
Abstract
The coordination chemistry of magnesium (Mg2+) was extensively explored. More recently; magnesium; which plays a role in over 80% of metabolic functions and governs over 350 enzymatic processes; is becoming increasingly linked to chronic disease—predominantly due to magnesium deficiency (hypomagnesemia). Supplemental dietary magnesium utilizing biorelevant chelate ligands is a proven method for counteracting hypomagnesemia. However, the coordination chemistry of such bio-relevant magnesium complexes is yet to be extensively explored or elucidated. It is the aim of this review to comprehensively describe what is currently known about common bio-relevant magnesium complexes from the perspective of coordination chemistry.
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36
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Sherlock ME, Breaker RR. Former orphan riboswitches reveal unexplored areas of bacterial metabolism, signaling, and gene control processes. RNA (NEW YORK, N.Y.) 2020; 26:675-693. [PMID: 32165489 PMCID: PMC7266159 DOI: 10.1261/rna.074997.120] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Comparative sequence analyses have been used to discover numerous classes of structured noncoding RNAs, some of which are riboswitches that specifically recognize small-molecule or elemental ion ligands and influence expression of adjacent downstream genes. Determining the correct identity of the ligand for a riboswitch candidate typically is aided by an understanding of the genes under its regulatory control. Riboswitches whose ligands were straightforward to identify have largely been associated with well-characterized metabolic pathways, such as coenzyme or amino acid biosynthesis. Riboswitch candidates whose ligands resist identification, collectively known as orphan riboswitches, are often associated with genes coding for proteins of unknown function, or genes for various proteins with no established link to one another. The cognate ligands for 16 former orphan riboswitch motifs have been identified to date. The successful pursuit of the ligands for these classes has provided insight into areas of biology that are not yet fully explored, such as ion homeostasis, signaling networks, and other previously underappreciated biochemical or physiological processes. Herein we discuss the strategies and methods used to match ligands with orphan riboswitch classes, and overview the lessons learned to inform and motivate ongoing efforts to identify ligands for the many remaining candidates.
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Affiliation(s)
- Madeline E Sherlock
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
| | - Ronald R Breaker
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA
- Howard Hughes Medical Institute, Yale University, New Haven, Connecticut 06520, USA
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37
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Jayalath K, Frisbie S, To M, Abeysirigunawardena S. Pseudouridine Synthase RsuA Captures an Assembly Intermediate that Is Stabilized by Ribosomal Protein S17. Biomolecules 2020; 10:biom10060841. [PMID: 32486254 PMCID: PMC7356742 DOI: 10.3390/biom10060841] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/28/2020] [Accepted: 05/28/2020] [Indexed: 01/03/2023] Open
Abstract
The ribosome is a large ribonucleoprotein complex that synthesizes protein in all living organisms. Ribosome biogenesis is a complex process that requires synchronization of various cellular events, including ribosomal RNA (rRNA) transcription, ribosome assembly, and processing and post-transcriptional modification of rRNA. Ribosome biogenesis is fine-tuned with various assembly factors, possibly including nucleotide modification enzymes. Ribosomal small subunit pseudouridine synthase A (RsuA) pseudouridylates U516 of 16S helix 18. Protein RsuA is a multi-domain protein that contains the N-terminal peripheral domain, which is structurally similar to the ribosomal protein S4. Our study shows RsuA preferably binds and pseudouridylates an assembly intermediate that is stabilized by ribosomal protein S17 over the native-like complex. In addition, the N-terminal domain truncated RsuA showed that the presence of the S4-like domain is important for RsuA substrate recognition.
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38
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Zou A, Lee S, Li J, Zhou R. Retained Stability of the RNA Structure in DNA Packaging Motor with a Single Mg2+ Ion Bound at the Double Mg-Clamp Structure. J Phys Chem B 2020; 124:701-707. [DOI: 10.1021/acs.jpcb.9b06428] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Aodong Zou
- Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, China
- Institute of Quantitative Biology and Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Sangyun Lee
- Computational Biological Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, United States
| | - Jingyuan Li
- Institute of Quantitative Biology and Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Ruhong Zhou
- Institute of Quantitative Biology and Department of Physics, Zhejiang University, Hangzhou 310027, China
- Computational Biological Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, United States
- Department of Chemistry, Columbia University, New York, New York 10027, United States
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Le Vay K, Salibi E, Song EY, Mutschler H. Nucleic Acid Catalysis under Potential Prebiotic Conditions. Chem Asian J 2020; 15:214-230. [PMID: 31714665 PMCID: PMC7003795 DOI: 10.1002/asia.201901205] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 11/05/2019] [Indexed: 01/25/2023]
Abstract
Catalysis by nucleic acids is indispensable for extant cellular life, and it is widely accepted that nucleic acid enzymes were crucial for the emergence of primitive life 3.5-4 billion years ago. However, geochemical conditions on early Earth must have differed greatly from the constant internal milieus of today's cells. In order to explore plausible scenarios for early molecular evolution, it is therefore essential to understand how different physicochemical parameters, such as temperature, pH, and ionic composition, influence nucleic acid catalysis and to explore to what extent nucleic acid enzymes can adapt to non-physiological conditions. In this article, we give an overview of the research on catalysis of nucleic acids, in particular catalytic RNAs (ribozymes) and DNAs (deoxyribozymes), under extreme and/or unusual conditions that may relate to prebiotic environments.
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Affiliation(s)
- Kristian Le Vay
- Biomimetic SystemsMax Planck Institute of BiochemistryAm Klopferspitz 1882152MartinsriedGermany
| | - Elia Salibi
- Biomimetic SystemsMax Planck Institute of BiochemistryAm Klopferspitz 1882152MartinsriedGermany
| | - Emilie Y. Song
- Biomimetic SystemsMax Planck Institute of BiochemistryAm Klopferspitz 1882152MartinsriedGermany
| | - Hannes Mutschler
- Biomimetic SystemsMax Planck Institute of BiochemistryAm Klopferspitz 1882152MartinsriedGermany
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40
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Pannwitt S, Slama K, Depoix F, Helm M, Schneider D. Against Expectations: Unassisted RNA Adsorption onto Negatively Charged Lipid Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:14704-14711. [PMID: 31626734 DOI: 10.1021/acs.langmuir.9b02830] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The composition and physicochemical properties of biological membranes can be altered by diverse membrane integral and peripheral proteins as well as by small molecules, natural and synthetic. Diverse oligonucleotides have been shown to electrostatically interact with cationic and bivalent ion loaded zwitterionic liposomes, leading to the formation of oligonucleotide-liposome aggregates. However, interaction of RNAs with other membrane surfaces remains ill understood. We used the nonnatural RNA10 to investigate RNA binding to anionic and net-uncharged membrane surfaces. RNA10 had initially been selected in a screen for nonnatural RNA motives that bind to phosphatidylcholine liposomes in the presence of Mg2+. Here we show that interaction of defined RNA molecules with membrane surfaces crucially depends on electrostatic surface properties. Furthermore, RNA10 electrostatically binds to anionic lipid bilayers in the absence of Mg2+ or other bivalent cations, and this interaction leads to measurably changed physicochemical properties of the bilayer and the oligonucleotide. Thus, the structure of polyanionic RNA can be modulated via contact with negatively charged membrane surfaces and vice versa.
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Affiliation(s)
- Stefanie Pannwitt
- Institute of Pharmacy and Biochemistry , Johannes Gutenberg University , Johann-Joachim-Becherweg 30 , 55128 Mainz , Germany
| | - Kaouthar Slama
- Institute of Pharmacy and Biochemistry , Johannes Gutenberg University , Staudinger Weg 5 , 55128 Mainz , Germany
| | - Frank Depoix
- Institute of Molecular Physiology , Johannes Gutenberg University , Johann-Joachim-Becherweg 9-11 , 55128 Mainz , Germany
| | - Mark Helm
- Institute of Pharmacy and Biochemistry , Johannes Gutenberg University , Staudinger Weg 5 , 55128 Mainz , Germany
| | - Dirk Schneider
- Institute of Pharmacy and Biochemistry , Johannes Gutenberg University , Johann-Joachim-Becherweg 30 , 55128 Mainz , Germany
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41
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Roy S, Hennelly SP, Lammert H, Onuchic JN, Sanbonmatsu KY. Magnesium controls aptamer-expression platform switching in the SAM-I riboswitch. Nucleic Acids Res 2019; 47:3158-3170. [PMID: 30605518 PMCID: PMC6451092 DOI: 10.1093/nar/gky1311] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 12/19/2018] [Accepted: 12/28/2018] [Indexed: 12/23/2022] Open
Abstract
Investigations of most riboswitches remain confined to the ligand-binding aptamer domain. However, during the riboswitch mediated transcription regulation process, the aptamer domain and the expression platform compete for a shared strand. If the expression platform dominates, an anti-terminator helix is formed, and the transcription process is active (ON state). When the aptamer dominates, transcription is terminated (OFF state). Here, we use an expression platform switching experimental assay and structure-based electrostatic simulations to investigate this ON-OFF transition of the full length SAM-I riboswitch and its magnesium concentration dependence. Interestingly, we find the ratio of the OFF population to the ON population to vary non-monotonically as magnesium concentration increases. Upon addition of magnesium, the aptamer domain pre-organizes, populating the OFF state, but only up to an intermediate magnesium concentration level. Higher magnesium concentration preferentially stabilizes the anti-terminator helix, populating the ON state, relatively destabilizing the OFF state. Magnesium mediated aptamer-expression platform domain closure explains this relative destabilization of the OFF state at higher magnesium concentration. Our study reveals the functional potential of magnesium in controlling transcription of its downstream genes and underscores the importance of a narrow concentration regime near the physiological magnesium concentration ranges, striking a balance between the OFF and ON states in bacterial gene regulation.
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Affiliation(s)
- Susmita Roy
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, USA
| | - Scott P Hennelly
- Theoretical Biology and Biophysics Group, Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.,New Mexico Consortium, Los Alamos, NM 87544, USA
| | - Heiko Lammert
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, USA
| | - José N Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, USA.,Departments of Physics and Astronomy, Chemistry, and Biosciences, Rice University, Houston, TX 77005, USA
| | - Karissa Y Sanbonmatsu
- Theoretical Biology and Biophysics Group, Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.,New Mexico Consortium, Los Alamos, NM 87544, USA
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42
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Owens MC, Clark SC, Yankey A, Somarowthu S. Identifying Structural Domains and Conserved Regions in the Long Non-Coding RNA lncTCF7. Int J Mol Sci 2019; 20:ijms20194770. [PMID: 31561429 PMCID: PMC6801803 DOI: 10.3390/ijms20194770] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 09/23/2019] [Accepted: 09/24/2019] [Indexed: 12/14/2022] Open
Abstract
Long non-coding RNA (lncRNA) biology is a rapidly growing area of study. Thousands of lncRNAs are implicated as key players in cellular pathways and cancer biology. However, the structure–function relationships of these novel biomolecules are not well understood. Recent structural studies suggest that lncRNAs contain modular structural domains, which play a crucial role in their function. Here, we hypothesized that such structural domains exist in lncTCF7, a conserved lncRNA implicated in the development and progression of several cancers. To understand the structure–function relationship of lncTCF7, we characterized its secondary structure using chemical probing methods. Our model revealed structural domains and conserved regions in lncTCF7. One of the modular domains identified here coincides with a known protein-interacting domain. The model reported herein is, to our knowledge, the first structural model of lncTCF7 and thus will serve to direct future studies that will provide fundamental insights into the function of this lncRNA.
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Affiliation(s)
- Michael C Owens
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19101, USA.
| | - Sean C Clark
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19101, USA.
| | - Allison Yankey
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19101, USA.
| | - Srinivas Somarowthu
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19101, USA.
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Importance of potassium ions for ribosome structure and function revealed by long-wavelength X-ray diffraction. Nat Commun 2019; 10:2519. [PMID: 31175275 PMCID: PMC6555806 DOI: 10.1038/s41467-019-10409-4] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 05/06/2019] [Indexed: 11/08/2022] Open
Abstract
The ribosome, the largest RNA-containing macromolecular machinery in cells, requires metal ions not only to maintain its three-dimensional fold but also to perform protein synthesis. Despite the vast biochemical data regarding the importance of metal ions for efficient protein synthesis and the increasing number of ribosome structures solved by X-ray crystallography or cryo-electron microscopy, the assignment of metal ions within the ribosome remains elusive due to methodological limitations. Here we present extensive experimental data on the potassium composition and environment in two structures of functional ribosome complexes obtained by measurement of the potassium anomalous signal at the K-edge, derived from long-wavelength X-ray diffraction data. We elucidate the role of potassium ions in protein synthesis at the three-dimensional level, most notably, in the environment of the ribosome functional decoding and peptidyl transferase centers. Our data expand the fundamental knowledge of the mechanism of ribosome function and structural integrity.
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44
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Hexahydrated Mg 2+ Binding and Outer-Shell Dehydration on RNA Surface. Biophys J 2019; 114:1274-1284. [PMID: 29590585 DOI: 10.1016/j.bpj.2018.01.040] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 01/30/2018] [Accepted: 01/31/2018] [Indexed: 10/17/2022] Open
Abstract
The interaction between metal ions, especially Mg2+ ions, and RNA plays a critical role in RNA folding. Upon binding to RNA, a metal ion that is fully hydrated in bulk solvent can become dehydrated. Here we use molecular dynamics simulation to investigate the dehydration of bound hexahydrated Mg2+ ions. We find that a hydrated Mg2+ ion in the RNA groove region can involve significant dehydration in the outer hydration shell. The first or innermost hydration shell of the Mg2+ ion, however, is retained during the simulation because of the strong ion-water electrostatic attraction. As a result, water-mediated hydrogen bonding remains an important form for Mg2+-RNA interaction. Analysis for ions at different binding sites shows that the most pronounced water deficiency relative to the fully hydrated state occurs at a radial distance of around 11 Å from the center of the ion. Based on the independent 200 ns molecular dynamics simulations for three different RNA structures (Protein Data Bank: 1TRA, 2TPK, and 437D), we find that Mg2+ ions overwhelmingly dominate over monovalent ions such as Na+ and K+ in ion-RNA binding. Furthermore, application of the free energy perturbation method leads to a quantitative relationship between the Mg2+ dehydration free energy and the local structural environment. We find that ΔΔGhyd, the change of the Mg2+ hydration free energy upon binding to RNA, varies linearly with the inverse distance between the Mg2+ ion and the nearby nonbridging oxygen atoms of the phosphate groups, and ΔΔGhyd can reach -2.0 kcal/mol and -3.0 kcal/mol for an Mg2+ ion bound to the surface and to the groove interior, respectively. In addition, the computation results in an analytical formula for the hydration ratio as a function of the average inverse Mg2+-O distance. The results here might be useful for further quantitative investigations of ion-RNA interactions in RNA folding.
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45
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Sun LZ, Chen SJ. Predicting RNA-Metal Ion Binding with Ion Dehydration Effects. Biophys J 2018; 116:184-195. [PMID: 30612712 DOI: 10.1016/j.bpj.2018.12.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 11/30/2018] [Accepted: 12/07/2018] [Indexed: 01/02/2023] Open
Abstract
Metal ions play essential roles in nucleic acids folding and stability. The interaction between metal ions and nucleic acids can be highly complicated because of the interplay between various effects such as ion correlation, fluctuation, and dehydration. These effects may be particularly important for multivalent ions such as Mg2+ ions. Previous efforts to model ion correlation and fluctuation effects led to the development of the Monte Carlo tightly bound ion model. Here, by incorporating ion hydration/dehydration effects into the Monte Carlo tightly bound ion model, we develop a, to our knowledge, new approach to predict ion binding. The new model enables predictions for not only the number of bound ions but also the three-dimensional spatial distribution of the bound ions. Furthermore, the new model reveals several intriguing features for the bound ions such as the mutual enhancement/inhibition in ion binding between the fully hydrated (diffuse) ions, the outer-shell dehydrated ions, and the inner-shell dehydrated ions and novel features for the monovalent-divalent ion interplay due to the hydration effect.
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Affiliation(s)
- Li-Zhen Sun
- Department of Applied Physics, Zhejiang University of Technology, Hangzhou, China; Department of Physics, Department of Biochemistry, and Informatics Institute, University of Missouri, Columbia, Missouri
| | - Shi-Jie Chen
- Department of Physics, Department of Biochemistry, and Informatics Institute, University of Missouri, Columbia, Missouri.
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46
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Welty R, Pabit SA, Katz AM, Calvey GD, Pollack L, Hall KB. Divalent ions tune the kinetics of a bacterial GTPase center rRNA folding transition from secondary to tertiary structure. RNA (NEW YORK, N.Y.) 2018; 24:1828-1838. [PMID: 30254137 PMCID: PMC6239185 DOI: 10.1261/rna.068361.118] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 09/20/2018] [Indexed: 05/22/2023]
Abstract
Folding of an RNA from secondary to tertiary structure often depends on divalent ions for efficient electrostatic charge screening (nonspecific association) or binding (specific association). To measure how different divalent cations modify folding kinetics of the 60 nucleotide Ecoli rRNA GTPase center, we combined stopped-flow fluorescence in the presence of Mg2+, Ca2+, or Sr2+ together with time-resolved small angle X-ray scattering (SAXS) in the presence of Mg2+ to observe the folding process. Immediately upon addition of each divalent ion, the RNA undergoes a transition from an extended state with secondary structure to a more compact structure. Subsequently, specific divalent ions modulate populations of intermediates in conformational ensembles along the folding pathway with transition times longer than 10 msec. Rate constants for the five folding transitions act on timescales from submillisecond to tens of seconds. The sensitivity of RNA tertiary structure to divalent cation identity affects all but the fastest events in RNA folding, and allowed us to identify those states that prefer Mg2+ The GTPase center RNA appears to have optimized its folding trajectory to specifically utilize this most abundant intracellular divalent ion.
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Affiliation(s)
- Robb Welty
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Suzette A Pabit
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Andrea M Katz
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - George D Calvey
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Kathleen B Hall
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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47
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Templeton C, Elber R. Why Does RNA Collapse? The Importance of Water in a Simulation Study of Helix-Junction-Helix Systems. J Am Chem Soc 2018; 140:16948-16951. [PMID: 30465606 DOI: 10.1021/jacs.8b11111] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Using computer simulations, we consider the balance of thermodynamic forces that collapse RNA. A model helix-junction-helix (HJH) construct is used to investigate the transition from an extended to a collapsed conformation. Conventional Molecular Dynamics and Milestoning Simulations are used to study the free energy profile of the process for two ion concentrations. We illustrate that HJH folds to a collapsed state with two types of counterions (Mg2+ and K+). By dissecting the free energy landscape into energetic and entropic contributions, we illustrate that the electrostatic forces between the RNA and the mobile ions do not drive the RNA to a collapsed state. Instead, entropy gains from water expulsion near the neighborhood of the RNA provide the stabilization free energy that tilt HJH into more compact structures. Further simulations of a three-helix hammerhead ribozyme show a similar behavior and support the idea of collapse due to increased gain in water entropy.
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Affiliation(s)
- Clark Templeton
- Department of Chemical Engineering , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Ron Elber
- Institute for Computational Engineering and Science, Department of Chemistry , University of Texas at Austin , Austin , Texas 78712 , United States
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48
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Bravo JPK, Borodavka A, Barth A, Calabrese AN, Mojzes P, Cockburn JJB, Lamb DC, Tuma R. Stability of local secondary structure determines selectivity of viral RNA chaperones. Nucleic Acids Res 2018; 46:7924-7937. [PMID: 29796667 PMCID: PMC6125681 DOI: 10.1093/nar/gky394] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 04/24/2018] [Accepted: 04/30/2018] [Indexed: 01/02/2023] Open
Abstract
To maintain genome integrity, segmented double-stranded RNA viruses of the Reoviridae family must accurately select and package a complete set of up to a dozen distinct genomic RNAs. It is thought that the high fidelity segmented genome assembly involves multiple sequence-specific RNA-RNA interactions between single-stranded RNA segment precursors. These are mediated by virus-encoded non-structural proteins with RNA chaperone-like activities, such as rotavirus (RV) NSP2 and avian reovirus σNS. Here, we compared the abilities of NSP2 and σNS to mediate sequence-specific interactions between RV genomic segment precursors. Despite their similar activities, NSP2 successfully promotes inter-segment association, while σNS fails to do so. To understand the mechanisms underlying such selectivity in promoting inter-molecular duplex formation, we compared RNA-binding and helix-unwinding activities of both proteins. We demonstrate that octameric NSP2 binds structured RNAs with high affinity, resulting in efficient intramolecular RNA helix disruption. Hexameric σNS oligomerizes into an octamer that binds two RNAs, yet it exhibits only limited RNA-unwinding activity compared to NSP2. Thus, the formation of intersegment RNA-RNA interactions is governed by both helix-unwinding capacity of the chaperones and stability of RNA structure. We propose that this protein-mediated RNA selection mechanism may underpin the high fidelity assembly of multi-segmented RNA genomes in Reoviridae.
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Affiliation(s)
- Jack P K Bravo
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
- School of Molecular and Cellular Biology, University of Leeds, Leeds, UK
| | - Alexander Borodavka
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
- School of Molecular and Cellular Biology, University of Leeds, Leeds, UK
- Department of Chemistry, Center for NanoScience (CeNS), Nanosystems Initiative Munich (NIM) and Centre for Integrated Protein Science Munich (CiPSM), Ludwig Maximilian University of Munich, Munich, Germany
| | - Anders Barth
- Department of Chemistry, Center for NanoScience (CeNS), Nanosystems Initiative Munich (NIM) and Centre for Integrated Protein Science Munich (CiPSM), Ludwig Maximilian University of Munich, Munich, Germany
| | - Antonio N Calabrese
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
- School of Molecular and Cellular Biology, University of Leeds, Leeds, UK
| | - Peter Mojzes
- Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, CZ-12116 Prague 2, Czech Republic
| | - Joseph J B Cockburn
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
- School of Molecular and Cellular Biology, University of Leeds, Leeds, UK
| | - Don C Lamb
- Department of Chemistry, Center for NanoScience (CeNS), Nanosystems Initiative Munich (NIM) and Centre for Integrated Protein Science Munich (CiPSM), Ludwig Maximilian University of Munich, Munich, Germany
| | - Roman Tuma
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
- School of Molecular and Cellular Biology, University of Leeds, Leeds, UK
- Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
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49
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Cellular conditions of weakly chelated magnesium ions strongly promote RNA stability and catalysis. Nat Commun 2018; 9:2149. [PMID: 29858572 PMCID: PMC5984629 DOI: 10.1038/s41467-018-04415-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 04/23/2018] [Indexed: 01/06/2023] Open
Abstract
Most RNA folding studies have been performed under non-physiological conditions of high concentrations (≥10 mM) of Mg2+free, while actual cellular concentrations of Mg2+free are only ~1 mM in a background of greater than 50 mM Mg2+total. To uncover cellular behavior of RNA, we devised cytoplasm mimic systems that include biological concentrations of amino acids, which weakly chelate Mg2+. Amino acid-chelated Mg2+ (aaCM) of ~15 mM dramatically increases RNA folding and prevents RNA degradation. Furthermore, aaCM enhance self-cleavage of several different ribozymes, up to 100,000-fold at Mg2+free of just 0.5 mM, indirectly through RNA compaction. Other metabolites that weakly chelate magnesium offer similar beneficial effects, which implies chelated magnesium may enhance RNA function in the cell in the same way. Overall, these results indicate that the states of Mg2+ should not be limited to free and bound only, as weakly bound Mg2+ strongly promotes RNA function under cellular conditions.
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50
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Cawez F, Duray E, Hu Y, Vandenameele J, Romão E, Vincke C, Dumoulin M, Galleni M, Muyldermans S, Vandevenne M. Combinatorial Design of a Nanobody that Specifically Targets Structured RNAs. J Mol Biol 2018; 430:1652-1670. [PMID: 29654796 DOI: 10.1016/j.jmb.2018.03.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 03/08/2018] [Accepted: 03/27/2018] [Indexed: 10/17/2022]
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