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Nüesch MF, Pietrek L, Holmstrom ED, Nettels D, von Roten V, Kronenberg-Tenga R, Medalia O, Hummer G, Schuler B. Nanosecond chain dynamics of single-stranded nucleic acids. Nat Commun 2024; 15:6010. [PMID: 39019880 PMCID: PMC11255343 DOI: 10.1038/s41467-024-50092-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 07/01/2024] [Indexed: 07/19/2024] Open
Abstract
The conformational dynamics of single-stranded nucleic acids are fundamental for nucleic acid folding and function. However, their elementary chain dynamics have been difficult to resolve experimentally. Here we employ a combination of single-molecule Förster resonance energy transfer, nanosecond fluorescence correlation spectroscopy, and nanophotonic enhancement to determine the conformational ensembles and rapid chain dynamics of short single-stranded nucleic acids in solution. To interpret the experimental results in terms of end-to-end distance dynamics, we utilize the hierarchical chain growth approach, simple polymer models, and refinement with Bayesian inference to generate structural ensembles that closely align with the experimental data. The resulting chain reconfiguration times are exceedingly rapid, in the 10-ns range. Solvent viscosity-dependent measurements indicate that these dynamics of single-stranded nucleic acids exhibit negligible internal friction and are thus dominated by solvent friction. Our results provide a detailed view of the conformational distributions and rapid dynamics of single-stranded nucleic acids.
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Affiliation(s)
- Mark F Nüesch
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Lisa Pietrek
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438, Frankfurt am Main, Germany
| | - Erik D Holmstrom
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
- Department of Chemistry, University of Kansas, Lawrence, KS, USA.
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, USA.
| | - Daniel Nettels
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Valentin von Roten
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Rafael Kronenberg-Tenga
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438, Frankfurt am Main, Germany.
- Institute for Biophysics, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany.
| | - Benjamin Schuler
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
- Department of Physics, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
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2
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Imamoto JM, Zauhar RJ, Bruist MF. Sarcin/Ricin Domain RNA Retains Its Structure Better Than A-RNA in Adaptively Biased Molecular Dynamics Simulations. J Phys Chem B 2022; 126:10018-10033. [PMID: 36417896 DOI: 10.1021/acs.jpcb.2c05859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Less than one in thirty of the RNA sequences transcribed in humans are translated into protein. The noncoding RNA (ncRNA) functions in catalysis, structure, regulation, and more. However, for the most part, these functions are poorly characterized. RNA is modular and described by motifs that include helical A-RNA with canonical Watson-Crick base-pairing as well as structures with only noncanonical base pairs. Understanding the structure and dynamics of motifs will aid in deciphering functions of specific ncRNAs. We present computational studies on a standard sarcin/ricin domain (SRD), citrus bark cracking viroid SRD, as well as A-RNA. We have applied enhanced molecular dynamics techniques that construct an inverse free-energy surface (iFES) determined by collective variables that monitor base-pairing and backbone conformation. Each SRD RNA is flanked on each side by A-RNA, allowing comparison of the behavior of these motifs in the same molecule. The RNA iFESs have single peaks, indicating that the combined motifs should denature as a single cohesive unit, rather than by regional melting. Local root-mean-square deviation (RMSD) analysis and communication propensity (CProp, variance in distances between residue pairs) reveal distinct motif properties. Our analysis indicates that the standard SRD is more stable than the viroid SRD, which is more stable than A-RNA. Base pairs at SRD to A-RNA transitions have limited flexibility. Application of CProp reveals extraordinary stiffness of the SRD, allowing residues on opposite sides of the motif to sense each other's motions.
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Affiliation(s)
- Jason M Imamoto
- Department of Chemistry and Biochemistry, St. Joseph's University, Philadelphia, Pennsylvania19131, United States
| | - Randy J Zauhar
- Department of Chemistry and Biochemistry, St. Joseph's University, Philadelphia, Pennsylvania19131, United States
| | - Michael F Bruist
- Department of Chemistry and Biochemistry, St. Joseph's University, Philadelphia, Pennsylvania19131, United States
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3
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Chowdhury S, Bhuiya S, Haque L, Das S. Influence of position of hydroxyl group of flavonoids on their binding with single stranded polyriboadenylic acid: A spectroscopic evaluation. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 246:119008. [PMID: 33038855 DOI: 10.1016/j.saa.2020.119008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 09/19/2020] [Accepted: 09/22/2020] [Indexed: 06/11/2023]
Abstract
Single stranded polyriboadenylic acid [poly (rA)] has been accepted widely as a suitable drug target owing to its vital role in the development of cancer since it controls gene expression during cell growth and differentiation. The biological properties of poly (rA) depend on its structural morphology. Pharmacologically active flavonoids can act as suitable binders to poly (rA) and significantly change its biophysical properties. Different factors favour flavonoid-poly (rA) binding. In our present work we have explored the role played by the position of hydroxyl groups in the flavonoids namely 3, 5, 6 and 7 hydroxyflavones in their course of interaction with poly (rA). A range of spectroscopic experiments reveal that 3HF binds best to poly (rA) among the four chosen flavonoids. This is probably due to the presence of a hydroxyl group in '3' position that enables it to exhibit ESIPT phenomenon which is missing for the other used flavonoids.
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Affiliation(s)
- Susmita Chowdhury
- Biophysical Chemistry Laboratory, Physical Chemistry Section, Department of Chemistry, Jadavpur University, 188 Raja S. C. Mallick Road, Kolkata 700032, India
| | - Sutanwi Bhuiya
- Biophysical Chemistry Laboratory, Physical Chemistry Section, Department of Chemistry, Jadavpur University, 188 Raja S. C. Mallick Road, Kolkata 700032, India
| | - Lucy Haque
- Biophysical Chemistry Laboratory, Physical Chemistry Section, Department of Chemistry, Jadavpur University, 188 Raja S. C. Mallick Road, Kolkata 700032, India
| | - Suman Das
- Biophysical Chemistry Laboratory, Physical Chemistry Section, Department of Chemistry, Jadavpur University, 188 Raja S. C. Mallick Road, Kolkata 700032, India.
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4
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Advanced approaches for elucidating structures of large RNAs using NMR spectroscopy and complementary methods. Methods 2020; 183:93-107. [DOI: 10.1016/j.ymeth.2020.01.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 11/11/2019] [Accepted: 01/16/2020] [Indexed: 11/23/2022] Open
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5
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Kladwang W, Topkar VV, Liu B, Rangan R, Hodges TL, Keane SC, Al-Hashimi H, Das R. Anomalous Reverse Transcription through Chemical Modifications in Polyadenosine Stretches. Biochemistry 2020; 59:2154-2170. [PMID: 32407625 DOI: 10.1021/acs.biochem.0c00020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Thermostable reverse transcriptases are workhorse enzymes underlying nearly all modern techniques for RNA structure mapping and for the transcriptome-wide discovery of RNA chemical modifications. Despite their wide use, these enzymes' behaviors at chemical modified nucleotides remain poorly understood. Wellington-Oguri et al. recently reported an apparent loss of chemical modification within putatively unstructured polyadenosine stretches modified by dimethyl sulfate or 2' hydroxyl acylation, as probed by reverse transcription. Here, reanalysis of these and other publicly available data, capillary electrophoresis experiments on chemically modified RNAs, and nuclear magnetic resonance spectroscopy on (A)12 and variants show that this effect is unlikely to arise from an unusual structure of polyadenosine. Instead, tests of different reverse transcriptases on chemically modified RNAs and molecules synthesized with single 1-methyladenosines implicate a previously uncharacterized reverse transcriptase behavior: near-quantitative bypass through chemical modifications within polyadenosine stretches. All tested natural and engineered reverse transcriptases (MMLV; SuperScript II, III, and IV; TGIRT-III; and MarathonRT) exhibit this anomalous bypass behavior. Accurate DMS-guided structure modeling of the polyadenylated HIV-1 3' untranslated region requires taking into account this anomaly. Our results suggest that poly(rA-dT) hybrid duplexes can trigger an unexpectedly effective reverse transcriptase bypass and that chemical modifications in mRNA poly(A) tails may be generally undercounted.
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Affiliation(s)
- Wipapat Kladwang
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Ved V Topkar
- Biophysics Program, Stanford University, Stanford, California 94305, United States
| | - Bei Liu
- Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710, United States
| | - Ramya Rangan
- Biophysics Program, Stanford University, Stanford, California 94305, United States
| | - Tracy L Hodges
- Biophysics Program, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Sarah C Keane
- Biophysics Program, University of Michigan, Ann Arbor, Michigan 48109, United States.,Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Hashim Al-Hashimi
- Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710, United States.,Department of Chemistry, Duke University School of Medicine, Durham, North Carolina 27710, United States
| | - Rhiju Das
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305, United States.,Biophysics Program, Stanford University, Stanford, California 94305, United States.,Department of Physics, Stanford University, Stanford, California 94305, United States
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6
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Plumridge A, Andresen K, Pollack L. Visualizing Disordered Single-Stranded RNA: Connecting Sequence, Structure, and Electrostatics. J Am Chem Soc 2019; 142:109-119. [PMID: 31804813 DOI: 10.1021/jacs.9b04461] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Disordered homopolymeric regions of single-stranded RNA, such as U or A tracts, are found within functional RNAs where they play distinct roles in defining molecular structure and facilitating recognition by partners. Despite this prominence, details of conformational and biophysical properties of these regions have not yet been resolved. We apply a number of experimental techniques to investigate the conformations of these biologically important motifs and provide quantitative measurements of their ion atmospheres. Single strands of RNA display pronounced sequence-dependent conformations that relate to the unique ion atmospheres each attracts. Chains of rU bases are relatively unstructured under all conditions, while chains of rA bases display distinct ordering through stacking or clustering motifs, depending on the composition of the surrounding solution. These dramatic structural differences are consistent with the measured disparity in ion composition and atmospheres around each homopolymer, revealing a complex interplay of base, ion, and single-strand ordering. The unique structural and ionic signatures of homopolymer ssRNAs explains their role(s) in folding structured RNAs and may explain their distinct recognition by protein partners.
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Affiliation(s)
- Alex Plumridge
- School of Applied and Engineering Physics , Cornell University , Ithaca , New York 14853 , United States
| | - Kurt Andresen
- Department of Physics , Gettysburg College , Gettysburg , Pennsylvania 17325 , United States
| | - Lois Pollack
- School of Applied and Engineering Physics , Cornell University , Ithaca , New York 14853 , United States
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7
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Marušič M, Schlagnitweit J, Petzold K. RNA Dynamics by NMR Spectroscopy. Chembiochem 2019; 20:2685-2710. [PMID: 30997719 PMCID: PMC6899578 DOI: 10.1002/cbic.201900072] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 04/12/2019] [Indexed: 12/22/2022]
Abstract
An ever-increasing number of functional RNAs require a mechanistic understanding. RNA function relies on changes in its structure, so-called dynamics. To reveal dynamic processes and higher energy structures, new NMR methods have been developed to elucidate these dynamics in RNA with atomic resolution. In this Review, we provide an introduction to dynamics novices and an overview of methods that access most dynamic timescales, from picoseconds to hours. Examples are provided as well as insight into theory, data acquisition and analysis for these different methods. Using this broad spectrum of methodology, unprecedented detail and invisible structures have been obtained and are reviewed here. RNA, though often more complicated and therefore neglected, also provides a great system to study structural changes, as these RNA structural changes are more easily defined-Lego like-than in proteins, hence the numerous revelations of RNA excited states.
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Affiliation(s)
- Maja Marušič
- Department of Medical Biochemistry and BiophysicsKarolinska InstitutetSolnavägen 917177StockholmSweden
| | - Judith Schlagnitweit
- Department of Medical Biochemistry and BiophysicsKarolinska InstitutetSolnavägen 917177StockholmSweden
| | - Katja Petzold
- Department of Medical Biochemistry and BiophysicsKarolinska InstitutetSolnavägen 917177StockholmSweden
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8
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Sequence-dependent RNA helix conformational preferences predictably impact tertiary structure formation. Proc Natl Acad Sci U S A 2019; 116:16847-16855. [PMID: 31375637 DOI: 10.1073/pnas.1901530116] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Structured RNAs and RNA complexes underlie biological processes ranging from control of gene expression to protein translation. Approximately 50% of nucleotides within known structured RNAs are folded into Watson-Crick (WC) base pairs, and sequence changes that preserve these pairs are typically assumed to preserve higher-order RNA structure and binding of macromolecule partners. Here, we report that indirect effects of the helix sequence on RNA tertiary stability are, in fact, significant but are nevertheless predictable from a simple computational model called RNAMake-∆∆G. When tested through the RNA on a massively parallel array (RNA-MaP) experimental platform, blind predictions for >1500 variants of the tectoRNA heterodimer model system achieve high accuracy (rmsd 0.34 and 0.77 kcal/mol for sequence and length changes, respectively). Detailed comparison of predictions to experiments support a microscopic picture of how helix sequence changes subtly modulate conformational fluctuations at each base-pair step, which accumulate to impact RNA tertiary structure stability. Our study reveals a previously overlooked phenomenon in RNA structure formation and provides a framework of computation and experiment for understanding helix conformational preferences and their impact across biological RNA and RNA-protein assemblies.
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9
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Giri RS, Mandal B. Unique crystallographic signatures of Boc-Gly-Phe-Phe-OMe and Boc-Gly-Phg-Phe-OMe and their self-association. CrystEngComm 2019. [DOI: 10.1039/c8ce01723a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The crystal structures and morphology of Boc-Gly-Phe-Phe-OMe (1) and Boc-Gly-Phg-Phe-OMe (2) are reported. While 1 forms a rare open turn conformation, 2 forms a β-sheet conformation.
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Affiliation(s)
- Rajat Subhra Giri
- Department of Chemistry
- Laboratory of Peptide and Amyloid Research
- Indian Institute of Technology Guwahati
- India
| | - Bhubaneswar Mandal
- Department of Chemistry
- Laboratory of Peptide and Amyloid Research
- Indian Institute of Technology Guwahati
- India
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10
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Merriman DK, Yuan J, Shi H, Majumdar A, Herschlag D, Al-Hashimi HM. Increasing the length of poly-pyrimidine bulges broadens RNA conformational ensembles with minimal impact on stacking energetics. RNA (NEW YORK, N.Y.) 2018; 24:1363-1376. [PMID: 30012568 PMCID: PMC6140463 DOI: 10.1261/rna.066258.118] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 07/05/2018] [Indexed: 05/03/2023]
Abstract
Helical elements separated by bulges frequently undergo transitions between unstacked and coaxially stacked conformations during the folding and function of noncoding RNAs. Here, we examine the dynamic properties of poly-pyrimidine bulges of varying length (n = 1-4, 7) across a range of Mg2+ concentrations using HIV-1 TAR RNA as a model system and solution NMR spectroscopy. In the absence of Mg2+, helices linked by bulges with n ≥ 3 residues adopt predominantly unstacked conformations (stacked population <15%), whereas one-bulge and two-bulge motifs adopt predominantly stacked conformations (stacked population >74%). In the presence of 3 mM Mg2+, the helices predominantly coaxially stack (stacked population >84%), regardless of bulge length, and the midpoint for the Mg2+-dependent stacking transition is within threefold regardless of bulge length. In the absence of Mg2+, the difference between free energy of interhelical coaxial stacking across the bulge variants is estimated to be ∼2.9 kcal/mol, based on an NMR chemical shift mapping with stacking being more energetically disfavored for the longer bulges. This difference decreases to ∼0.4 kcal/mol in the presence of Mg2+ NMR RDCs and resonance intensity data show increased dynamics in the stacked state with increasing bulge length in the presence of Mg2+ We propose that Mg2+ helps to neutralize the growing electrostatic repulsion in the stacked state with increasing bulge length thereby increasing the number of coaxial conformations that are sampled. Energetically compensated interhelical stacking dynamics may help to maximize the conformational adaptability of RNA and allow a wide range of conformations to be optimally stabilized by proteins and ligands.
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Affiliation(s)
- Dawn K Merriman
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | - Jiayi Yuan
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
- Department of Biology, Duke University, Durham, North Carolina 27708, USA
| | - Honglue Shi
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | - Ananya Majumdar
- Biomolecular NMR Facility, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Daniel Herschlag
- Department of Biochemistry, Stanford University, Stanford, California 94305, USA
| | - Hashim M Al-Hashimi
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
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11
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Warden MS, Tonelli M, Cornilescu G, Liu D, Hopersberger LJ, Ponniah K, Pascal SM. Structure of RNA Stem Loop B from the Picornavirus Replication Platform. Biochemistry 2017; 56:2549-2557. [PMID: 28459542 DOI: 10.1021/acs.biochem.7b00141] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The presumptive RNA cloverleaf at the start of the 5'-untranslated region of the picornavirus genome is an essential element in replication. Stem loop B (SLB) of the cloverleaf is a recognition site for the host polyC-binding protein, which initiates a switch from translation to replication. Here we present the solution structure of human rhinovirus isotype 14 SLB using nuclear magnetic resonance spectroscopy. SLB adopts a predominantly A-form helical structure. The stem contains five Watson-Crick base pairs and one wobble base pair and is capped by an eight-nucleotide loop. The wobble base pair introduces perturbations into the helical parameters but does not appear to introduce flexibility. However, the helix major groove appears to be accessible. Flexibility is seen throughout the loop and in the terminal nucleotides. The pyrimidine-rich region of the loop, the apparent recognition site for the polyC-binding protein, is the most disordered region of the structure.
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Affiliation(s)
- Meghan S Warden
- Department of Chemistry and Biochemistry, Old Dominion University , Norfolk, Virginia 23529, United States
| | - Marco Tonelli
- National Magnetic Resonance Facility at Madison (NMRFAM), University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Gabriel Cornilescu
- National Magnetic Resonance Facility at Madison (NMRFAM), University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Dong Liu
- Department of Chemistry and Biochemistry, Old Dominion University , Norfolk, Virginia 23529, United States
| | - Lorelei J Hopersberger
- Department of Chemistry and Biochemistry, Old Dominion University , Norfolk, Virginia 23529, United States
| | - Komala Ponniah
- Department of Chemistry and Biochemistry, Old Dominion University , Norfolk, Virginia 23529, United States
| | - Steven M Pascal
- Department of Chemistry and Biochemistry, Old Dominion University , Norfolk, Virginia 23529, United States
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12
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Chalmers G, Glushka JN, Foley BL, Woods RJ, Prestegard JH. Direct NOE simulation from long MD trajectories. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 265:1-9. [PMID: 26826977 PMCID: PMC4818662 DOI: 10.1016/j.jmr.2016.01.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 01/10/2016] [Accepted: 01/12/2016] [Indexed: 05/08/2023]
Abstract
A software package, MD2NOE, is presented which calculates Nuclear Overhauser Effect (NOE) build-up curves directly from molecular dynamics (MD) trajectories. It differs from traditional approaches in that it calculates correlation functions directly from the trajectory instead of extracting inverse sixth power distance terms as an intermediate step in calculating NOEs. This is particularly important for molecules that sample conformational states on a timescale similar to molecular reorientation. The package is tested on sucrose and results are shown to differ in small but significant ways from those calculated using an inverse sixth power assumption. Results are also compared to experiment and found to be in reasonable agreement despite an expected underestimation of water viscosity by the water model selected.
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Affiliation(s)
- G Chalmers
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, United States
| | - J N Glushka
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, United States
| | - B L Foley
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, United States
| | - R J Woods
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, United States
| | - J H Prestegard
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, United States.
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13
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Efficient large-scale preparation and purification of short single-stranded RNA oligonucleotides. Biotechniques 2016; 60:75-83. [PMID: 26842352 DOI: 10.2144/000114383] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Accepted: 12/12/2015] [Indexed: 11/23/2022] Open
Abstract
Sequence-specific RNA recognition by RNA-binding proteins plays a crucial role in the post-translational regulation of gene expression. Biophysical and biochemical studies help to unravel the principles of sequence-specific RNA recognition, but the methods used require large amounts of single-stranded RNA (ssRNA). Here we present a fast and robust method for large-scale preparation and purification of short ssRNA oligonucleotides for biochemical, biophysical, and structural studies. We designed an efficiently folding, self-cleaving hammerhead (HH) ribozyme to prepare ssRNA oligonucleotides. Hammerhead ribozyme RNAs self-cleave with over 95% efficiency during in vitro transcription as a function of magnesium concentration to produce high yields of the desired ssRNA products. The resulting ssRNAs can be purified from crude transcription reactions by denaturing anion-exchange chromatography and then desalted by weak anion-exchange chromatography using volatile ammonium bicarbonate buffer solutions. The ssRNA oligonucleotides produced this way are homogenous, as judged by mass spectrometry (MS), and are suitable for biochemical and biophysical studies. Moreover, for high-resolution NMR structure determination of RNA-protein complexes, our protocol enables efficient preparation of ssRNA oligonucleotides with various isotope-labeling schemes which are not commercially available.
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14
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Moschen T, Wunderlich CH, Spitzer R, Levic J, Micura R, Tollinger M, Kreutz C. Ligand-detected relaxation dispersion NMR spectroscopy: dynamics of preQ1-RNA binding. Angew Chem Int Ed Engl 2015; 54:560-3. [PMID: 25403518 PMCID: PMC4353840 DOI: 10.1002/anie.201409779] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Indexed: 12/21/2022]
Abstract
An NMR-based approach to characterizing the binding kinetics of ligand molecules to biomolecules, like RNA or proteins, by ligand-detected Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion experiments is described. A (15)N-modified preQ1 ligand is used to acquire relaxation dispersion experiments in the presence of low amounts of the Fsu class I preQ1 aptamer RNA, and increasing ligand concentrations to probe the RNA small molecule interaction. Our experimental data strongly support the conformational selection mechanism postulated. The approach gives direct access to two parameters of a ligand-receptor interaction: the off rate and the population of the small molecule-receptor complex. A detailed description of the kinetics underlying the ligand binding process is of crucial importance to fully understanding a riboswitch's function and to evaluate potential new antibiotics candidates targeting the noncoding RNA species. Ligand-detected NMR relaxation dispersion experiments represent a valuable diagnostic tool for the characterization of binding mechanisms.
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Affiliation(s)
- Thomas Moschen
- Institute of Organic Chemistry, Centre for Molecular Biosciences (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck (Austria)
| | - Christoph Hermann Wunderlich
- Institute of Organic Chemistry, Centre for Molecular Biosciences (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck (Austria)
| | - Romana Spitzer
- Institute of Organic Chemistry, Centre for Molecular Biosciences (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck (Austria)
| | - Jasmin Levic
- Institute of Organic Chemistry, Centre for Molecular Biosciences (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck (Austria)
| | - Ronald Micura
- Institute of Organic Chemistry, Centre for Molecular Biosciences (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck (Austria)
| | - Martin Tollinger
- Institute of Organic Chemistry, Centre for Molecular Biosciences (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck (Austria)
| | - Christoph Kreutz
- Institute of Organic Chemistry, Centre for Molecular Biosciences (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck (Austria)
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15
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Moschen T, Wunderlich CH, Spitzer R, Levic J, Micura R, Tollinger M, Kreutz C. Ligand-Detected Relaxation Dispersion NMR Spectroscopy: Dynamics of preQ1-RNA Binding. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201409779] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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