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Dayie TK, Olenginski LT, Taiwo KM. Isotope Labels Combined with Solution NMR Spectroscopy Make Visible the Invisible Conformations of Small-to-Large RNAs. Chem Rev 2022; 122:9357-9394. [PMID: 35442658 PMCID: PMC9136934 DOI: 10.1021/acs.chemrev.1c00845] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Indexed: 02/07/2023]
Abstract
RNA is central to the proper function of cellular processes important for life on earth and implicated in various medical dysfunctions. Yet, RNA structural biology lags significantly behind that of proteins, limiting mechanistic understanding of RNA chemical biology. Fortunately, solution NMR spectroscopy can probe the structural dynamics of RNA in solution at atomic resolution, opening the door to their functional understanding. However, NMR analysis of RNA, with only four unique ribonucleotide building blocks, suffers from spectral crowding and broad linewidths, especially as RNAs grow in size. One effective strategy to overcome these challenges is to introduce NMR-active stable isotopes into RNA. However, traditional uniform labeling methods introduce scalar and dipolar couplings that complicate the implementation and analysis of NMR measurements. This challenge can be circumvented with selective isotope labeling. In this review, we outline the development of labeling technologies and their application to study biologically relevant RNAs and their complexes ranging in size from 5 to 300 kDa by NMR spectroscopy.
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Affiliation(s)
- Theodore K. Dayie
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Lukasz T. Olenginski
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Kehinde M. Taiwo
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
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2
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Synthesis of atom-specific nucleobase and ribose labeled uridine phosphoramidite for NMR analysis of large RNAs. MONATSHEFTE FUR CHEMIE 2021. [DOI: 10.1007/s00706-021-02851-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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3
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Olenginski LT, Taiwo KM, LeBlanc RM, Dayie TK. Isotope-Labeled RNA Building Blocks for NMR Structure and Dynamics Studies. Molecules 2021; 26:5581. [PMID: 34577051 PMCID: PMC8466439 DOI: 10.3390/molecules26185581] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 09/05/2021] [Accepted: 09/07/2021] [Indexed: 01/19/2023] Open
Abstract
RNA structural research lags behind that of proteins, preventing a robust understanding of RNA functions. NMR spectroscopy is an apt technique for probing the structures and dynamics of RNA molecules in solution at atomic resolution. Still, RNA analysis by NMR suffers from spectral overlap and line broadening, both of which worsen for larger RNAs. Incorporation of stable isotope labels into RNA has provided several solutions to these challenges. In this review, we summarize the benefits and limitations of various methods used to obtain isotope-labeled RNA building blocks and how they are used to prepare isotope-labeled RNA for NMR structure and dynamics studies.
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Affiliation(s)
- Lukasz T. Olenginski
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA; (L.T.O.); (K.M.T.); (R.M.L.)
| | - Kehinde M. Taiwo
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA; (L.T.O.); (K.M.T.); (R.M.L.)
| | - Regan M. LeBlanc
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA; (L.T.O.); (K.M.T.); (R.M.L.)
- Vertex Pharmaceuticals, 50 Northern Avenue, Boston, MA 02210, USA
| | - Theodore K. Dayie
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA; (L.T.O.); (K.M.T.); (R.M.L.)
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4
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Chemo-enzymatic synthesis of [2-13C, 7-15 N]-ATP for facile NMR analysis of RNA. MONATSHEFTE FUR CHEMIE 2020. [DOI: 10.1007/s00706-020-02667-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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5
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Asadi-Atoi P, Barraud P, Tisne C, Kellner S. Benefits of stable isotope labeling in RNA analysis. Biol Chem 2020; 400:847-865. [PMID: 30893050 DOI: 10.1515/hsz-2018-0447] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 03/11/2019] [Indexed: 02/07/2023]
Abstract
RNAs are key players in life as they connect the genetic code (DNA) with all cellular processes dominated by proteins. They contain a variety of chemical modifications and many RNAs fold into complex structures. Here, we review recent progress in the analysis of RNA modification and structure on the basis of stable isotope labeling techniques. Mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy are the key tools and many breakthrough developments were made possible by the analysis of stable isotope labeled RNA. Therefore, we discuss current stable isotope labeling techniques such as metabolic labeling, enzymatic labeling and chemical synthesis. RNA structure analysis by NMR is challenging due to two major problems that become even more salient when the size of the RNA increases, namely chemical shift overlaps and line broadening leading to complete signal loss. Several isotope labeling strategies have been developed to provide solutions to these major issues, such as deuteration, segmental isotope labeling or site-specific labeling. Quantification of modified nucleosides in RNA by MS is only possible through the application of stable isotope labeled internal standards. With nucleic acid isotope labeling coupled mass spectrometry (NAIL-MS), it is now possible to analyze the dynamic processes of post-transcriptional RNA modification and demodification. The trend, in both NMR and MS RNA analytics, is without doubt shifting from the analysis of snapshot moments towards the development and application of tools capable of analyzing the dynamics of RNA structure and modification profiles.
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Affiliation(s)
- Paria Asadi-Atoi
- Department of Chemistry, Ludwig-Maximilians-University Munich, Butenandtstr. 5-13, D-81377 Munich, Germany
| | - Pierre Barraud
- Institut de Biologie Physico-Chimique (IBPC), UMR 8261, CNRS, Université Paris Diderot, 13 rue Pierre et Marie Curie, F-75005 Paris, France
| | - Carine Tisne
- Institut de Biologie Physico-Chimique (IBPC), UMR 8261, CNRS, Université Paris Diderot, 13 rue Pierre et Marie Curie, F-75005 Paris, France
| | - Stefanie Kellner
- Department of Chemistry, Ludwig-Maximilians-University Munich, Butenandtstr. 5-13, D-81377 Munich, Germany
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6
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Keyhani S, Goldau T, Blümler A, Heckel A, Schwalbe H. Chemo-Enzymatic Synthesis of Position-Specifically Modified RNA for Biophysical Studies including Light Control and NMR Spectroscopy. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201807125] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Sara Keyhani
- Institute for Organic Chemistry and Chemical Biology; Center for Biomolecular Magnetic Resonance; Goethe University Frankfurt am Main; Max-von-Laue-Strasse 7 60438 Frankfurt/Main Germany
- Institute for Organic Chemistry and Chemical Biology; Goethe University Frankfurt am Main; Max-von-Laue-Strasse 7 60438 Frankfurt/Main Germany
| | - Thomas Goldau
- Institute for Organic Chemistry and Chemical Biology; Goethe University Frankfurt am Main; Max-von-Laue-Strasse 7 60438 Frankfurt/Main Germany
| | - Anja Blümler
- Institute for Organic Chemistry and Chemical Biology; Goethe University Frankfurt am Main; Max-von-Laue-Strasse 7 60438 Frankfurt/Main Germany
| | - Alexander Heckel
- Institute for Organic Chemistry and Chemical Biology; Goethe University Frankfurt am Main; Max-von-Laue-Strasse 7 60438 Frankfurt/Main Germany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology; Center for Biomolecular Magnetic Resonance; Goethe University Frankfurt am Main; Max-von-Laue-Strasse 7 60438 Frankfurt/Main Germany
- Institute for Organic Chemistry and Chemical Biology; Goethe University Frankfurt am Main; Max-von-Laue-Strasse 7 60438 Frankfurt/Main Germany
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7
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Keyhani S, Goldau T, Blümler A, Heckel A, Schwalbe H. Chemo-Enzymatic Synthesis of Position-Specifically Modified RNA for Biophysical Studies including Light Control and NMR Spectroscopy. Angew Chem Int Ed Engl 2018; 57:12017-12021. [PMID: 30007102 DOI: 10.1002/anie.201807125] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Indexed: 02/04/2023]
Abstract
The investigation of non-coding RNAs requires RNAs containing modifications at every possible position within the oligonucleotide. Here, we present the chemo-enzymatic RNA synthesis containing photoactivatable or 13 C,15 N-labelled nucleosides. All four ribonucleotides containing ortho-nitrophenylethyl (NPE) photocages, photoswitchable azobenzene C-nucleotides and 13 C,15 N-labelled nucleotides were incorporated position-specifically in high yields. We applied this approach for the synthesis of light-inducible 2'dG-sensing riboswitch variants and detected ligand-induced structural reorganization upon irradiation by NMR spectroscopy. This chemo-enzymatic method opens the possibility to incorporate a wide range of modifications at any desired position of RNAs of any lengths beyond the limits of solid-phase synthesis.
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Affiliation(s)
- Sara Keyhani
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Max-von-Laue-Strasse 7, 60438, Frankfurt/Main, Germany.,Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Max-von-Laue-Strasse 7, 60438, Frankfurt/Main, Germany
| | - Thomas Goldau
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Max-von-Laue-Strasse 7, 60438, Frankfurt/Main, Germany
| | - Anja Blümler
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Max-von-Laue-Strasse 7, 60438, Frankfurt/Main, Germany
| | - Alexander Heckel
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Max-von-Laue-Strasse 7, 60438, Frankfurt/Main, Germany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Max-von-Laue-Strasse 7, 60438, Frankfurt/Main, Germany.,Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Max-von-Laue-Strasse 7, 60438, Frankfurt/Main, Germany
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8
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Marchanka A, Kreutz C, Carlomagno T. Isotope labeling for studying RNA by solid-state NMR spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2018; 71:151-164. [PMID: 29651587 DOI: 10.1007/s10858-018-0180-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 04/07/2018] [Indexed: 06/08/2023]
Abstract
Nucleic acids play key roles in most biological processes, either in isolation or in complex with proteins. Often they are difficult targets for structural studies, due to their dynamic behavior and high molecular weight. Solid-state nuclear magnetic resonance spectroscopy (ssNMR) provides a unique opportunity to study large biomolecules in a non-crystalline state at atomic resolution. Application of ssNMR to RNA, however, is still at an early stage of development and presents considerable challenges due to broad resonances and poor dispersion. Isotope labeling, either as nucleotide-specific, atom-specific or segmental labeling, can resolve resonance overlaps and reduce the line width, thus allowing ssNMR studies of RNA domains as part of large biomolecules or complexes. In this review we discuss the methods for RNA production and purification as well as numerous approaches for isotope labeling of RNA. Furthermore, we give a few examples that emphasize the instrumental role of isotope labeling and ssNMR for studying RNA as part of large ribonucleoprotein complexes.
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Affiliation(s)
- Alexander Marchanka
- Centre for Biomolecular Drug Research (BMWZ) and Institute of Organic Chemistry, Leibniz University Hannover, Schneiderberg 38, 30167, Hanover, Germany
| | - Christoph Kreutz
- Organic Chemistry, University of Innsbruck (CCB), Innrain 80/82, 6020, Innsbruck, Austria
| | - Teresa Carlomagno
- Centre for Biomolecular Drug Research (BMWZ) and Institute of Organic Chemistry, Leibniz University Hannover, Schneiderberg 38, 30167, Hanover, Germany.
- Helmholtz Centre for Infection Research, Group of NMR-based Structural Chemistry, Inhoffenstraße 7, 38124, Brunswick, Germany.
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9
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Le MT, Brown RE, Simon AE, Dayie TK. In vivo, large-scale preparation of uniformly (15)N- and site-specifically (13)C-labeled homogeneous, recombinant RNA for NMR studies. Methods Enzymol 2016; 565:495-535. [PMID: 26577743 DOI: 10.1016/bs.mie.2015.07.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Knowledge of how ribonucleic acid (RNA) structures fold to form intricate, three-dimensional structures has provided fundamental insights into understanding the biological functions of RNA. Nuclear magnetic resonance (NMR) spectroscopy is a particularly useful high-resolution technique to investigate the dynamic structure of RNA. Effective study of RNA by NMR requires enrichment with isotopes of (13)C or (15)N or both. Here, we present a method to produce milligram quantities of uniformly (15)N- and site-specifically (13)C-labeled RNAs using wild-type K12 and mutant tktA Escherichia coli in combination with a tRNA-scaffold approach. The method includes a double selection protocol to obtain an E. coli clone with consistently high expression of the recombinant tRNA-scaffold. We also present protocols for the purification of the tRNA-scaffold from a total cellular RNA extract and the excision of the RNA of interest from the tRNA-scaffold using DNAzymes. Finally, we showcase NMR applications to demonstrate the benefit of using in vivo site-specifically (13)C-labeled RNA.
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Affiliation(s)
- My T Le
- Department of Chemistry and Biochemistry,Center for Biomolecular Structure and Organization, University of Maryland, College Park, Maryland, USA
| | - Rachel E Brown
- Department of Chemistry and Biochemistry, Department of Cellular Biology and Molecular Genetics, Center for Biomolecular Structure and Organization, University of Maryland, College Park, Maryland, USA
| | - Anne E Simon
- Department of Chemistry and Biochemistry, Department of Cellular Biology and Molecular Genetics, Center for Biomolecular Structure and Organization, University of Maryland, College Park, Maryland, USA
| | - T Kwaku Dayie
- Department of Chemistry and Biochemistry,Center for Biomolecular Structure and Organization, University of Maryland, College Park, Maryland, USA.
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10
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Nelissen FHT, Tessari M, Wijmenga SS, Heus HA. Stable isotope labeling methods for DNA. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2016; 96:89-108. [PMID: 27573183 DOI: 10.1016/j.pnmrs.2016.06.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/02/2016] [Accepted: 06/02/2016] [Indexed: 06/06/2023]
Abstract
NMR is a powerful method for studying proteins and nucleic acids in solution. The study of nucleic acids by NMR is far more challenging than for proteins, which is mainly due to the limited number of building blocks and unfavorable spectral properties. For NMR studies of DNA molecules, (site specific) isotope enrichment is required to facilitate specific NMR experiments and applications. Here, we provide a comprehensive review of isotope-labeling strategies for obtaining stable isotope labeled DNA as well as specifically stable isotope labeled building blocks required for enzymatic DNA synthesis.
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Affiliation(s)
- Frank H T Nelissen
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, The Netherlands.
| | - Marco Tessari
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, The Netherlands.
| | - Sybren S Wijmenga
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, The Netherlands.
| | - Hans A Heus
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, The Netherlands.
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11
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Alvarado LJ, Longhini AP, LeBlanc RM, Chen B, Kreutz C, Dayie TK. Chemo-enzymatic synthesis of selectively ¹³C/¹⁵N-labeled RNA for NMR structural and dynamics studies. Methods Enzymol 2015; 549:133-62. [PMID: 25432748 DOI: 10.1016/b978-0-12-801122-5.00007-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
RNAs are an important class of cellular regulatory elements, and they are well characterized by X-ray crystallography and nuclear magnetic resonance (NMR) spectroscopy in their folded or bound states. However, the apo or unfolded states are more difficult to characterize by either method. Particularly, effective NMR spectroscopy studies of RNAs in the past were hampered by chemical shift overlap of resonances and associated rapid signal loss due to line broadening for RNAs larger than the median size found in the PDB (~25 nt); most functional riboswitches are bigger than this median size. Incorporation of selective site-specific (13)C/(15)N-labeled nucleotides into RNAs promises to overcome this NMR size limitation. Unlike previous isotopic enrichment methods such as phosphoramidite, de novo, uniform-labeling, and selective-biomass approaches, this newer chemical-enzymatic selective method presents a number of advantages for producing labeled nucleotides over these other methods. For example, total chemical synthesis of nucleotides, followed by solid-phase synthesis of RNA using phosphoramidite chemistry, while versatile in incorporating isotope labels into RNA at any desired position, faces problems of low yields (<10%) that drop precipitously for oligonucleotides larger than 50 nt. The alternative method of de novo pyrimidine biosynthesis of NTPs is also a robust technique, with modest yields of up to 45%, but it comes at the cost of using 16 enzymes, expensive substrates, and difficulty in making some needed labeling patterns such as selective labeling of the ribose C1' and C5' and the pyrimidine nucleobase C2, C4, C5, or C6. Biomass-produced, uniformly or selectively labeled NTPs offer a third method, but suffer from low overall yield per labeled input metabolite and isotopic scrambling with only modest suppression of (13)C-(13)C couplings. In contrast to these four methods, our current chemo-enzymatic approach overcomes most of these shortcomings and allows for the synthesis of gram quantities of nucleotides with >80% yields while using a limited number of enzymes, six at most. The unavailability of selectively labeled ribose and base precursors had prevented the effective use of this versatile method until now. Recently, we combined an improved organic synthetic approach that selectively places (13)C/(15)N labels in the pyrimidine nucleobase (either (15)N1, (15)N3, (13)C2, (13)C4, (13)C5, or (13)C6 or any combination) with a very efficient enzymatic method to couple ribose with uracil to produce previously unattainable labeling patterns (Alvarado et al., 2014). Herein we provide detailed steps of both our chemo-enzymatic synthesis of custom nucleotides and their incorporation into RNAs with sizes ranging from 29 to 155 nt and showcase the dramatic improvement in spectral quality of reduced crowding and narrow linewidths. Applications of this selective labeling technology should prove valuable in overcoming two major obstacles, chemical shift overlap of resonances and associated rapid signal loss due to line broadening, that have impeded studying the structure and dynamics of large RNAs such as full-length riboswitches larger than the ~25 nt median size of RNA NMR structures found in the PDB.
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Affiliation(s)
- Luigi J Alvarado
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, College Park, Maryland, USA
| | - Andrew P Longhini
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, College Park, Maryland, USA
| | - Regan M LeBlanc
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, College Park, Maryland, USA
| | - Bin Chen
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, College Park, Maryland, USA
| | - Christoph Kreutz
- Institute of Organic Chemistry and Center for Molecular Biosciences (CMBI), University of Innsbruck, Innrain, Innsbruck, Austria
| | - T Kwaku Dayie
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, College Park, Maryland, USA.
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12
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Alvarado LJ, LeBlanc RM, Longhini AP, Keane SC, Jain N, Yildiz ZF, Tolbert BS, D'Souza VM, Summers MF, Kreutz C, Dayie TK. Regio-selective chemical-enzymatic synthesis of pyrimidine nucleotides facilitates RNA structure and dynamics studies. Chembiochem 2014; 15:1573-7. [PMID: 24954297 DOI: 10.1002/cbic.201402130] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Indexed: 12/16/2022]
Abstract
Isotope labeling has revolutionized NMR studies of small nucleic acids, but to extend this technology to larger RNAs, site-specific labeling tools to expedite NMR structural and dynamics studies are required. Using enzymes from the pentose phosphate pathway, we coupled chemically synthesized uracil nucleobase with specifically (13) C-labeled ribose to synthesize both UTP and CTP in nearly quantitative yields. This chemoenzymatic method affords a cost-effective preparation of labels that are unattainable by current methods. The methodology generates versatile (13) C and (15) N labeling patterns which, when employed with relaxation-optimized NMR spectroscopy, effectively mitigate problems of rapid relaxation that result in low resolution and sensitivity. The methodology is demonstrated with RNAs of various sizes, complexity, and function: the exon splicing silencer 3 (27 nt), iron responsive element (29 nt), Pro-tRNA (76 nt), and HIV-1 core encapsidation signal (155 nt).
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Affiliation(s)
- Luigi J Alvarado
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, 1115 Biomolecular Sciences Building, College Park, MD 20782 (USA)
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13
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Biosynthetic preparation of 13C/15N-labeled rNTPs for high-resolution NMR studies of RNAs. Methods Mol Biol 2013; 941:227-45. [PMID: 23065565 DOI: 10.1007/978-1-62703-113-4_17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
High-resolution investigations of the structure and dynamics of RNA molecules by nuclear magnetic resonance (NMR) methodologies require the production of (13)C/(15)N-isotopically labeled samples. A common strategy entails the preparation of (13)C/(15)N-enriched ribonucleoside 5'-triphosphates (rNTPs) to be incorporated into RNA oligomers by in vitro transcription. Here, we describe the methods to obtain isotopically labeled rNTP in a uniform or selective fashion from bacterial cultures, using common and versatile E. coli strains. This chapter also covers procedures for extraction and digestion of the total RNA from bacterial cells, purification of the ribonucleoside 5'-monophosphates and their enzymatic phosphorylation to rNTPs.
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14
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Auclair J, Lépine F, Villemur R. A liquid chromatography - mass spectrometry method to measure ¹³C-isotope enrichment for DNA stable-isotope probing. Can J Microbiol 2012; 58:287-92. [PMID: 22356592 DOI: 10.1139/w11-133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
DNA stable-isotope probing (DNA-SIP) is a cultivation-independent technique that makes it possible to associate metabolic function and taxonomic identity in a wide range of terrestrial and aquatic environments. In DNA-SIP, DNA is labeled via the assimilation of a labeled growth substrate that is subsequently used to identify microorganisms involved in assimilation of the substrate. However, the labeling time has to be sufficient to obtain labeled DNA but not so long such that cross-feeding of ¹³C-labeled metabolites from the primary consumers to nontarget species can occur. Confirmation that the DNA is isotopically labeled in DNA-SIP assays can be achieved using an isotope ratio mass spectrometer. In this study, we describe the development of a method using liquid chromatography (HPLC) coupled to a quadrupole mass spectrometer (QMS) to measure the ¹³C enrichment of thymine incorporated into DNA in Escherichia coli cultures fed with [¹³C]acetate. The method involved the hydrolysis of DNA extracted from the cultures that released the nucleotides, followed by the separation of the thymine by HPLC on a reverse-phase C₈ column in isocratic elution mode and the detection and quantification of ¹³C-labeled thymine by QMS. To mimic a DNA-SIP assay, a DNA mixture was made using ¹³C-labeled E. coli DNA with DNA extracted from five bacterial species. The HPLC-MS method was able to measure the correct proportion of ¹³C-DNA in the mix. This method can then be used as an alternative to the use of isotope ratio mass spectrometry in DNA-SIP assays.
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Affiliation(s)
- Julie Auclair
- INRS-Institut Armand-Frappier, 531 boulevard des Prairies, Laval, QC H7V 1B7, Canada
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15
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Thakur CS, Luo Y, Chen B, Eldho NV, Dayie TK. Biomass production of site selective 13C/15N nucleotides using wild type and a transketolase E. coli mutant for labeling RNA for high resolution NMR. JOURNAL OF BIOMOLECULAR NMR 2012; 52:103-14. [PMID: 22124680 PMCID: PMC3277826 DOI: 10.1007/s10858-011-9586-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 11/06/2011] [Indexed: 05/25/2023]
Abstract
Characterization of the structure and dynamics of nucleic acids by NMR benefits significantly from position specifically labeled nucleotides. Here an E. coli strain deficient in the transketolase gene (tktA) and grown on glucose that is labeled at different carbon sites is shown to facilitate cost-effective and large scale production of useful nucleotides. These nucleotides are site specifically labeled in C1' and C5' with minimal scrambling within the ribose ring. To demonstrate the utility of this labeling approach, the new site-specific labeled and the uniformly labeled nucleotides were used to synthesize a 36-nt RNA containing the catalytically essential domain 5 (D5) of the brown algae group II intron self-splicing ribozyme. The D5 RNA was used in binding and relaxation studies probed by NMR spectroscopy. Key nucleotides in the D5 RNA that are implicated in binding Mg(2+) ions are well resolved. As a result, spectra obtained using selectively labeled nucleotides have higher signal-to-noise ratio compared to those obtained using uniformly labeled nucleotides. Thus, compared to the uniformly (13)C/(15)N-labeled nucleotides, these specifically labeled nucleotides eliminate the extensive (13)C-(13)C coupling within the nitrogenous base and ribose ring, give rise to less crowded and more resolved NMR spectra, and accurate relaxation rates without the need for constant-time or band-selective decoupled NMR experiments. These position selective labeled nucleotides should, therefore, find wide use in NMR analysis of biologically interesting RNA molecules.
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Affiliation(s)
- Chandar S. Thakur
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - Yiling Luo
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - Bin Chen
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - Nadukkudy V. Eldho
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - T. Kwaku Dayie
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
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16
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Thakur CS, Dayie TK. Asymmetry of 13C labeled 3-pyruvate affords improved site specific labeling of RNA for NMR spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2012; 52:65-77. [PMID: 22089526 PMCID: PMC3266500 DOI: 10.1007/s10858-011-9582-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2011] [Accepted: 10/10/2011] [Indexed: 05/07/2023]
Abstract
Selective isotopic labeling provides an unparalleled window within which to study the structure and dynamics of RNAs by high resolution NMR spectroscopy. Unlike commonly used carbon sources, the asymmetry of (13)C-labeled pyruvate provides selective labeling in both the ribose and base moieties of nucleotides using Escherichia coli variants, that until now were not feasible. Here we show that an E. coli mutant strain that lacks succinate and malate dehydrogenases (DL323) and grown on [3-(13)C]-pyruvate affords ribonucleotides with site specific labeling at C5' (~95%) and C1' (~42%) and minimal enrichment elsewhere in the ribose ring. Enrichment is also achieved at purine C2 and C8 (~95%) and pyrimidine C5 (~100%) positions with minimal labeling at pyrimidine C6 and purine C5 positions. These labeling patterns contrast with those obtained with DL323 E. coli grown on [1, 3-(13)C]-glycerol for which the ribose ring is labeled in all but the C4' carbon position, leading to multiplet splitting of the C1', C2' and C3' carbon atoms. The usefulness of these labeling patterns is demonstrated with a 27-nt RNA fragment derived from the 30S ribosomal subunit. Removal of the strong magnetic coupling within the ribose and base leads to increased sensitivity, substantial simplification of NMR spectra, and more precise and accurate dynamic parameters derived from NMR relaxation measurements. Thus these new labels offer valuable probes for characterizing the structure and dynamics of RNA that were previously limited by the constraint of uniformly labeled nucleotides.
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Affiliation(s)
- Chandar S. Thakur
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - T. Kwaku Dayie
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
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Thakur CS, Dayie TK. Asymmetry of (13)C labeled 3-pyruvate affords improved site specific labeling of RNA for NMR spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2011; 51:505-17. [PMID: 22038649 PMCID: PMC3222825 DOI: 10.1007/s10858-011-9581-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Accepted: 10/11/2011] [Indexed: 05/15/2023]
Abstract
Selective isotopic labeling provides an unparalleled window within which to study the structure and dynamics of RNAs by high resolution NMR spectroscopy. Unlike commonly used carbon sources, the asymmetry of (13)C-labeled pyruvate provides selective labeling in both the ribose and base moieties of nucleotides using E. coli variants, that until now were not feasible. Here we show that an E. coli mutant strain that lacks succinate and malate dehydrogenases (DL323) and grown on [3-(13)C]-pyruvate affords ribonucleotides with site specific labeling at C5' (~95%) and C1' (~42%) and minimal enrichment elsewhere in the ribose ring. Enrichment is also achieved at purine C2 and C8 (~95%) and pyrimidine C5 (~100%) positions with minimal labeling at pyrimidine C6 and purine C5 positions. These labeling patterns contrast with those obtained with DL323 E. coli grown on [1, 3-(13)C]-glycerol for which the ribose ring is labeled in all but the C4' carbon position, leading to multiplet splitting of the C1', C2' and C3' carbon atoms. The usefulness of these labeling patterns is demonstrated with a 27-nt RNA fragment derived from the 30S ribosomal subunit. Removal of the strong magnetic coupling within the ribose and base leads to increased sensitivity, substantial simplification of NMR spectra, and more precise and accurate dynamic parameters derived from NMR relaxation measurements. Thus these new labels offer valuable probes for characterizing the structure and dynamics of RNA that were previously limited by the constraint of uniformly labeled nucleotides.
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Affiliation(s)
- Chandar S. Thakur
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - T. Kwaku Dayie
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
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Thakur CS, Sama JN, Jackson ME, Chen B, Dayie TK. Selective 13C labeling of nucleotides for large RNA NMR spectroscopy using an E. coli strain disabled in the TCA cycle. JOURNAL OF BIOMOLECULAR NMR 2010; 48:179-92. [PMID: 21057854 PMCID: PMC2988204 DOI: 10.1007/s10858-010-9454-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Accepted: 07/28/2010] [Indexed: 05/05/2023]
Abstract
Escherichia coli (E. coli) is an ideal organism to tailor-make labeled nucleotides for biophysical studies of RNA. Recently, we showed that adding labeled formate enhanced the isotopic enrichment at protonated carbon sites in nucleotides. In this paper, we show that growth of a mutant E. coli strain DL323 (lacking succinate and malate dehydrogenases) on (13)C-2-glycerol and (13)C-1,3-glycerol enables selective labeling at many useful sites for RNA NMR spectroscopy. For DL323 E. coli grown in (13)C-2-glycerol without labeled formate, all the ribose carbon atoms are labeled except the C3' and C5' carbon positions. Consequently the C1', C2' and C4' positions remain singlet. In addition, only the pyrimidine base C6 atoms are substantially labeled to ~96% whereas the C2 and C8 atoms of purine are labeled to ~5%. Supplementing the growth media with (13)C-formate increases the labeling at C8 to ~88%, but not C2. Not unexpectedly, addition of exogenous formate is unnecessary for attaining the high enrichment levels of ~88% for the C2 and C8 purine positions in a (13)C-1,3-glycerol based growth. Furthermore, the ribose ring is labeled in all but the C4' carbon position, such that the C2' and C3' positions suffer from multiplet splitting but the C5' position remains singlet and the C1' position shows a small amount of residual C1'-C2' coupling. As expected, all the protonated base atoms, except C6, are labeled to ~90%. In addition, labeling with (13)C-1,3-glycerol affords an isolated methylene ribose with high enrichment at the C5' position (~90%) that makes it particularly attractive for NMR applications involving CH(2)-TROSY modules without the need for decoupling the C4' carbon. To simulate the tumbling of large RNA molecules, perdeuterated glycerol was added to a mixture of the four nucleotides, and the methylene TROSY experiment recorded at various temperatures. Even under conditions of slow tumbling, all the expected carbon correlations were observed, which indicates this approach of using nucleotides obtained from DL323 E. coli will be applicable to high molecular weight RNA systems.
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Affiliation(s)
- Chandar S. Thakur
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - Jacob N. Sama
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - Melantha E. Jackson
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - Bin Chen
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - T. Kwaku Dayie
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
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19
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Thakur CS, Brown ME, Sama JN, Jackson ME, Dayie TK. Growth of wildtype and mutant E. coli strains in minimal media for optimal production of nucleic acids for preparing labeled nucleotides. Appl Microbiol Biotechnol 2010; 88:771-9. [PMID: 20730533 PMCID: PMC2938442 DOI: 10.1007/s00253-010-2813-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2010] [Revised: 07/23/2010] [Accepted: 07/30/2010] [Indexed: 01/27/2023]
Abstract
Since RNAs lie at the center of most cellular processes, there is a need for synthesizing large amounts of RNAs made from stable isotope-labeled nucleotides to advance the study of their structure and dynamics by nuclear magnetic resonance (NMR) spectroscopy. A particularly effective means of obtaining labeled nucleotides is to harvest these nucleotides from bacteria grown in defined minimal media supplemented with 15NH4Cl and various carbon sources. Given the high cost of carbon precursors required for labeling nucleic acids for NMR studies, it becomes important to evaluate the optimal growth for commonly used strains under standard minimal media conditions. Such information is lacking. In this study, we characterize the growth for Escherichia coli strains K12, K10zwf, and DL323 in three minimal media with isotopic-labeled carbon sources of acetate, glycerol, and glycerol combined with formate. Of the three media, the LeMaster-Richards and the Studier media outperform the commonly used M9 media and both support optimal growth of E. coli for the production of nucleotides. However, the growth of all three E. coli strains in acetate is reduced almost twofold compared to growth in glycerol. Analysis of the metabolic pathway and previous gene array studies help to explain this differential growth in glycerol and acetate. These studies should benefit efforts to make selective 13C-15N isotopic-labeled nucleotides for synthesizing biologically important RNAs.
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Affiliation(s)
- Chandar S Thakur
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, 1115 Biomolecular Sciences, Bldg #296, College Park, MD 20742-3360, USA
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20
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Dayie TK, Thakur CS. Site-specific labeling of nucleotides for making RNA for high resolution NMR studies using an E. coli strain disabled in the oxidative pentose phosphate pathway. JOURNAL OF BIOMOLECULAR NMR 2010; 47:19-31. [PMID: 20309608 PMCID: PMC2859161 DOI: 10.1007/s10858-010-9405-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Accepted: 02/26/2010] [Indexed: 05/22/2023]
Abstract
Escherichia coli (E. coli) is a versatile organism for making nucleotides labeled with stable isotopes ((13)C, (15)N, and/or (2)H) for structural and molecular dynamics characterizations. Growth of a mutant E. coli strain deficient in the pentose phosphate pathway enzyme glucose-6-phosphate dehydrogenase (K10-1516) on 2-(13)C-glycerol and (15)N-ammonium sulfate in Studier minimal medium enables labeling at sites useful for NMR spectroscopy. However, (13)C-sodium formate combined with (13)C-2-glycerol in the growth media adds labels to new positions. In the absence of labeled formate, both C5 and C6 positions of the pyrimidine rings are labeled with minimal multiplet splitting due to (1)J(C5C6) scalar coupling. However, the C2/C8 sites within purine rings and the C1'/C3'/C5' positions within the ribose rings have reduced labeling. Addition of (13)C-labeled formate leads to increased labeling at the base C2/C8 and the ribose C1'/C3'/C5' positions; these new specific labels result in two- to three-fold increase in the number of resolved resonances. This use of formate and (15)N-ammonium sulfate promises to extend further the utility of these alternate site specific labels to make labeled RNA for downstream biophysical applications such as structural, dynamics and functional studies of interesting biologically relevant RNAs.
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Affiliation(s)
- T Kwaku Dayie
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360, USA.
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21
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Key labeling technologies to tackle sizeable problems in RNA structural biology. Int J Mol Sci 2008; 9:1214-1240. [PMID: 19325801 PMCID: PMC2635727 DOI: 10.3390/ijms9071214] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Revised: 06/06/2008] [Accepted: 07/14/2008] [Indexed: 01/09/2023] Open
Abstract
The ability to adopt complex three-dimensional (3D) structures that can rapidly interconvert between multiple functional states (folding and dynamics) is vital for the proper functioning of RNAs. Consequently, RNA structure and dynamics necessarily determine their biological function. In the post-genomic era, it is clear that RNAs comprise a larger proportion (>50%) of the transcribed genome compared to proteins (< or =2%). Yet the determination of the 3D structures of RNAs lags considerably behind those of proteins and to date there are even fewer investigations of dynamics in RNAs compared to proteins. Site specific incorporation of various structural and dynamic probes into nucleic acids would likely transform RNA structural biology. Therefore, various methods for introducing probes for structural, functional, and biotechnological applications are critically assessed here. These probes include stable isotopes such as (2)H, (13)C, (15)N, and (19)F. Incorporation of these probes using improved RNA ligation strategies promises to change the landscape of structural biology of supramacromolecules probed by biophysical tools such as nuclear magnetic resonance (NMR) spectroscopy, X-ray crystallography and Raman spectroscopy. Finally, some of the structural and dynamic problems that can be addressed using these technological advances are outlined.
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Johnson JE, Julien KR, Hoogstraten CG. Alternate-site isotopic labeling of ribonucleotides for NMR studies of ribose conformational dynamics in RNA. JOURNAL OF BIOMOLECULAR NMR 2006; 35:261-74. [PMID: 16937241 DOI: 10.1007/s10858-006-9041-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2006] [Accepted: 06/02/2006] [Indexed: 05/04/2023]
Abstract
Heteronuclear NMR spin relaxation studies of conformational dynamics are coming into increasing use to help understand the functions of ribozymes and other RNAs. Due to strong 13C-13C magnetic interactions within the ribose ring, however, these studies have thus far largely been limited to (13)C and (15)N resonances on the nucleotide base side chains. We report here the application of the alternate-site (13)C isotopic labeling scheme, pioneered by LeMaster for relaxation studies of amino acid side chains, to nucleic acid systems. We have used different strains of E. coli to prepare mononucleotides containing (13)C label in one of two patterns: Either C1' or C2' in addition to C4', termed (1'/2',4') labeling, or nearly complete labeling at the C2' and C4' sites only, termed (2',4') labeling. These patterns provide isolated 13C-1H spin systems on the labeled carbon atoms and thus allow spin relaxation studies without interference from 13C-13C scalar or dipolar coupling. Using relaxation studies of AMP dissolved in glycerol at varying temperature to produce systems with correlation times characteristic of different size RNAs, we demonstrate the removal of errors due to 13C-13C interaction in T (1) measurements of larger nucleic acids and in T (1rho) measurements in RNA molecules. By extending the applicability of spin relaxation measurements to backbone ribose groups, this technology should greatly improve the flexibility and completeness of NMR analyses of conformational dynamics in RNA.
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Affiliation(s)
- James E Johnson
- Department of Biochemistry & Molecular Biology, Michigan State University, 212 Biochemistry Building, East Lansing, MI, 48824, USA
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23
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Latham MP, Brown DJ, McCallum SA, Pardi A. NMR methods for studying the structure and dynamics of RNA. Chembiochem 2006; 6:1492-505. [PMID: 16138301 DOI: 10.1002/cbic.200500123] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Proper functioning of RNAs requires the formation of complex three-dimensional structures combined with the ability to rapidly interconvert between multiple functional states. This review covers recent advances in isotope-labeling strategies and NMR experimental approaches that have promise for facilitating solution structure determinations and dynamics studies of biologically active RNAs. Improved methods for the production of isotopically labeled RNAs combined with new multidimensional heteronuclear NMR experiments make it possible to dramatically reduce spectral crowding and simplify resonance assignments for RNAs. Several novel applications of experiments that directly detect hydrogen-bonding interactions are discussed. These studies demonstrate how NMR spectroscopy can be used to distinguish between possible secondary structures and identify mechanisms of ligand binding in RNAs. A variety of recently developed methods for measuring base and sugar residual dipolar couplings are described. NMR residual dipolar coupling techniques provide valuable data for determining the long-range structure and orientation of helical regions in RNAs. A number of studies are also presented where residual dipolar coupling constraints are used to determine the global structure and dynamics of RNAs. NMR relaxation data can be used to probe the dynamics of macromolecules in solution. The power dependence of transverse rotating-frame relaxation rates was used here to study dynamics in the minimal hammerhead ribozyme. Improved methods for isotopically labeling RNAs combined with new types of structural data obtained from a growing repertoire of NMR experiments are facilitating structural and dynamic studies of larger RNAs.
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Affiliation(s)
- Michael P Latham
- Department of Chemistry and Biochemistry, 215 UCB, University of Colorado, Boulder, CO 80309-0215, USA
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Scott LG, Tolbert TJ, Williamson JR. Preparation of specifically 2H- and 13C-labeled ribonucleotides. Methods Enzymol 2000; 317:18-38. [PMID: 10829270 DOI: 10.1016/s0076-6879(00)17004-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- L G Scott
- The Scripps Research Institute, La Jolla, California 92037, USA
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25
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Holland JA, Hansen MR, Du Z, Hoffman DW. An examination of coaxial stacking of helical stems in a pseudoknot motif: the gene 32 messenger RNA pseudoknot of bacteriophage T2. RNA (NEW YORK, N.Y.) 1999; 5:257-271. [PMID: 10024177 PMCID: PMC1369757 DOI: 10.1017/s1355838299981360] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The RNA pseudoknot located at the 5' end of the gene 32 messenger RNA of bacteriophage T2 contains two A-form helical stems connected by two loops, in an H-type pseudoknot topology. A combination of multidimensional NMR methods and isotope labeling were used to investigate the pseudoknot structure, resulting in a more detailed structural model than provided by earlier homonuclear NMR studies. Of particular significance, the interface between the stacked helical stems within the pseudoknot motif is described in detail. The two stems are stacked in a coaxial manner, with an approximately 18 degrees rotation of stem1 relative to stem2 about an axis that is parallel to the helical axis. This rotation serves to relieve what would otherwise be a relatively close phosphate-phosphate contact at the junction of the two stems, while preserving the stabilizing effects of base stacking. The ability of the NMR data to determine pseudoknot bending was critically assessed. The data were found to be a modestly precise indicator of pseudoknot bending, with the angle between the helical axes of stem1 and stem2 being in the range of 15+/-15 degrees. Pseudoknot models with bend angles within this range are equally consistent with the data, since they differ by only small amounts in the relatively short-range interproton distances from which the structure was derived. The gene 32 messenger RNA pseudoknot was compared with other RNA structures with coaxial or near-coaxial stacked helical stems.
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Affiliation(s)
- J A Holland
- Department of Chemistry and Biochemistry, Institute for Cell and Molecular Biology, University of Texas at Austin, 78712, USA
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26
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Smith DE, Su JY, Jucker FM. Efficient enzymatic synthesis of 13C,15N-labeled DNA for NMR studies. JOURNAL OF BIOMOLECULAR NMR 1997; 10:245-253. [PMID: 9390402 DOI: 10.1023/a:1018358602001] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The power of heteronuclear NMR spectroscopy to study macromolecules and their complexes has been amply demonstrated over the last decade. The obstacle to routinely applying these techniques to the study of DNA has been the synthesis of 13C,15N-labeled DNA. Here we present a simple and efficient method to generate isotope-labeled DNA for NMR studies that is as easy as that for isotope labeling of RNA. The method was used to synthesize a uniformly 13C,15N-labeled 32-nucleotide DNA that binds to human basic fibroblast growth factor with high affinity and specificity. Isotope-edited experiments were applied to the 13C,15N-labeled DNA bound to unlabeled protein, and the 13C,15N-labeled DNA was also examined in complex with 15N-labeled protein. The NMR experiments show that the DNA adopts a well-defined stable structure when bound to the protein, and illustrate the potential of 13C,15N-labeled DNA for structural studies of DNA-protein complexes.
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Affiliation(s)
- D E Smith
- NeXstar Pharmaceuticals Inc., Boulder, CO 80301, USA
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27
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Nikonowicz EP, Kalurachchi K, DeJong E. Comparison of H5 and H8 relaxation rates of a 2H/13C/15N labeled RNA oligonucleotide with selective protonation at C5 and C8. FEBS Lett 1997; 415:109-13. [PMID: 9326379 DOI: 10.1016/s0014-5793(97)01034-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Uniformly 13C/15N enriched ribonucleotide monophosphates have been prepared with extensive deuterium enrichment of the non-exchangeable positions. The purine C8 and pyrimidine C5 base positions were selectively protonated prior to incorporation of the individual nucleotide triphosphates into an RNA oligonucleotide. The longitudinal and transverse relaxation rates of the H8 and H5 resonances of this deuterated molecule were compared with the relaxation rates of the corresponding protonated, 13C/15N enriched RNA molecule. Deuteration disrupts the efficiency of 1H-1H dipolar relaxation and reduces the longitudinal and transverse magnetization relaxation rates on average to 25% and 68%, respectively, of the values measured for the non-deuterated RNA molecule. Importantly, the longitudinal relaxation rates remain sufficiently rapid (> 1s[-1]) to permit the use of short recovery delays in multidimensional NMR experiments without significant loss of sensitivity.
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Affiliation(s)
- E P Nikonowicz
- Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA.
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28
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Nikonowicz EP, Michnicka M, Kalurachchi K, DeJong E. Preparation and characterization of a uniformly 2 H/ 15 N-labeled RNA oligonucleotide for NMR studies. Nucleic Acids Res 1997; 25:1390-6. [PMID: 9060434 PMCID: PMC146606 DOI: 10.1093/nar/25.7.1390] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
An RNA oligonucleotide that contains the binding site for Escherichia coli ribosomal protein S8 was prepared with uniform 15N isotopic enrichment and uniform deuterium enrichment at all non-exchangeable sites using enzymatic methods. The RNA binding site, which contains 44 nt, forms a hairpin in solution and requires Mg2+for proper folding. The longitudinal magnetization recovery rates of the exchangeable protons were compared for the [2H,15N]-enriched RNA molecule and for the corresponding fully [2H,15N]-enriched RNA hairpin. It was found that 1H-1H dipolar relaxation significantly contributes to the recovery of exchangeable proton longitudinal magnetization. The exchangeable proton resonance line widths were less affected by deuteration, indicating that chemical exchange with H2O remains the dominant mechanism of transverse magnetization relaxation. Nevertheless, deuteration of this RNA hairpin was found to enhance the sensitivity of NOE-based experiments relative to the fully protonated hairpin and to simplify 2D NMR spectra. The increased signal-to-noise ratio facilitated the assignment of the cytidine amino resonances and several of the purine nucleotide amino resonances and permitted the identification of NOE crosspeaks that could not be observed in spectra of the fully protonated RNA hairpin.
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Affiliation(s)
- E P Nikonowicz
- Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA.
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