1
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Hetzke T, Vogel M, Halbritter ALJ, Saha S, Suess B, Sigurdsson ST, Prisner TF. Simultaneous Localization of Two High Affinity Divalent Metal Ion Binding Sites in the Tetracycline RNA Aptamer with Mn 2+-Based Pulsed Dipolar EPR Spectroscopy. J Phys Chem Lett 2023; 14:11421-11428. [PMID: 38084602 DOI: 10.1021/acs.jpclett.3c02566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Mg2+ ions play an essential part in stabilizing the tertiary structure of nucleic acids. While the importance of these ions is well documented, their localization and elucidation of their role in the structure and dynamics of nucleic acids are often challenging. In this work, pulsed electron-electron double resonance spectroscopy (PELDOR, also known as DEER) was used to localize two high affinity divalent metal ion binding sites in the tetracycline RNA aptamer with high accuracy. For this purpose, the aptamer was labeled at different positions with a semirigid nitroxide spin label and diamagnetic Mg2+ was replaced with paramagnetic Mn2+, which did not alter the folding process or ligand binding. Out of the several divalent metal ion binding sites that are known from the crystal structure, two binding sites with high affinity were detected: one that is located at the ligand binding center and another at the J1/2 junction of the RNA.
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Affiliation(s)
- Thilo Hetzke
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Marc Vogel
- Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | | | - Subham Saha
- Department of Chemistry, Science Institute, University of Iceland, 107 Reykjavik, Iceland
| | - Beatrix Suess
- Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Snorri Th Sigurdsson
- Department of Chemistry, Science Institute, University of Iceland, 107 Reykjavik, Iceland
| | - Thomas F Prisner
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
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2
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Dörrenhaus R, Wagner PK, Kath-Schorr S. Two are not enough: synthetic strategies and applications of unnatural base pairs. Biol Chem 2023; 404:883-896. [PMID: 37354104 DOI: 10.1515/hsz-2023-0169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 06/05/2023] [Indexed: 06/26/2023]
Abstract
Nucleic acid chemistry is a rapidly evolving field, and the need for novel nucleotide modifications and artificial nucleotide building blocks for diagnostic and therapeutic use, material science or for studying cellular processes continues unabated. This review focusses on the development and application of unnatural base pairs as part of an expanded genetic alphabet. Not only recent developments in "nature-like" artificial base pairs are presented, but also current synthetic methods to get access to C-glycosidic nucleotides. Wide-ranging viability in synthesis is a prerequisite for the successful use of unnatural base pairs in a broader spectrum and will be discussed.
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3
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Giannoulis A, Ackermann K, Bogdanov A, Cordes DB, Higgins C, Ward J, Slawin AMZ, Taylor JE, Bode BE. Synthesis of mono-nitroxides and of bis-nitroxides with varying electronic through-bond communication. Org Biomol Chem 2023; 21:375-385. [PMID: 36524609 PMCID: PMC9811921 DOI: 10.1039/d2ob01863b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Nitroxides are a unique class of persistent radicals finding a wide range of applications, from spin probes to polarizing agents, and recently bis-nitroxides have been used as proof-of-concept molecules for quantum information processing. Here we present the syntheses of pyrroline-based nitroxide (NO) radicals and give a comparision of two possible synthetic routes to form two key intermediates, namely 2,2,5,5-tetramethylpyrroline-1-oxyl-3-acetylene (TPA) and 1-oxyl-2,2,5,5-tetramethylpyrroline-3-carboxylic acid (TPC). TPC and TPA were then used as precursors for the synthesis of three model compounds featuring two distant NO groups with a variable degree of conjugation and thus electronic communication between them. Using relatively facile synthetic routes, we produced a number of mono- and bis-nitroxides with the structures of multiple compounds unambiguously characterized by X-ray crystallography, while Continuous Wave Electron Paramagnetic Resonance (CW-EPR) allowed us to quantify the electronic communication in the bis-nitroxides. Our study expands the repertoire of mono- and bis-nitroxides with possibilities of exploiting them for studying quantum coherence effects and as polarizing agents.
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Affiliation(s)
- Angeliki Giannoulis
- Department of Chemical and Biological Physics, Weizmann Institute of ScienceRehovot76100Israel,EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St AndrewsNorth HaughSt AndrewsKY16 9STUK
| | - Katrin Ackermann
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St AndrewsNorth HaughSt AndrewsKY16 9STUK
| | - Alexey Bogdanov
- Department of Chemical and Biological Physics, Weizmann Institute of ScienceRehovot76100Israel
| | - David B. Cordes
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St AndrewsNorth HaughSt AndrewsKY16 9STUK
| | - Catherine Higgins
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St AndrewsNorth HaughSt AndrewsKY16 9STUK
| | - Joshua Ward
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St AndrewsNorth HaughSt AndrewsKY16 9STUK
| | - Alexandra M. Z. Slawin
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St AndrewsNorth HaughSt AndrewsKY16 9STUK
| | - James E. Taylor
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St AndrewsNorth HaughSt AndrewsKY16 9STUK,Department of Chemistry, University of BathClaverton DownBathBA2 7AYUK
| | - Bela E. Bode
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St AndrewsNorth HaughSt AndrewsKY16 9STUK
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4
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Kaiser F, Endeward B, Collauto A, Scheffer U, Prisner TF, Göbel MW. Spin-Labeled Riboswitch Synthesized from a Protected TPA Phosphoramidite Building Block. Chemistry 2022; 28:e202201822. [PMID: 35903916 PMCID: PMC9804336 DOI: 10.1002/chem.202201822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Indexed: 01/05/2023]
Abstract
The nitroxide TPA (2,2,5,5-tetramethyl-pyrrolin-1-oxyl-3-acetylene) is an excellent spin label for EPR studies of RNA. Previous synthetic methods, however, are complicated and require special equipment. Herein, we describe a uridine derived phosphoramidite with a photocaged TPA unit attached. The light sensitive 2-nitrobenzyloxymethyl group can be removed in high yield by short irradiation at 365 nm. Based on this approach, a doubly spin-labeled 27mer neomycin sensing riboswitch was synthesized and studied by PELDOR. The overall thermal stability of the fold is not much reduced by TPA. In-line probing nevertheless detected changes in local mobility.
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Affiliation(s)
- Frank Kaiser
- Institute for Organic Chemistry and Chemical BiologyGoethe University FrankfurtMax-von-Laue-Strasse 760438Frankfurt am MainGermany
| | - Burkhard Endeward
- Institute for Physical and Theoretical ChemistryGoethe University FrankfurtMax-von-Laue-Strasse 760438Frankfurt am MainGermany
| | - Alberto Collauto
- Institute for Physical and Theoretical ChemistryGoethe University FrankfurtMax-von-Laue-Strasse 760438Frankfurt am MainGermany
| | - Ute Scheffer
- Institute for Organic Chemistry and Chemical BiologyGoethe University FrankfurtMax-von-Laue-Strasse 760438Frankfurt am MainGermany
| | - Thomas F. Prisner
- Institute for Physical and Theoretical ChemistryGoethe University FrankfurtMax-von-Laue-Strasse 760438Frankfurt am MainGermany
| | - Michael W. Göbel
- Institute for Organic Chemistry and Chemical BiologyGoethe University FrankfurtMax-von-Laue-Strasse 760438Frankfurt am MainGermany
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5
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Bornewasser L, Kath-Schorr S. Preparation of Site-Specifically Spin-Labeled RNA by in Vitro Transcription Using an Expanded Genetic Alphabet. Methods Mol Biol 2022; 2439:223-240. [PMID: 35226325 DOI: 10.1007/978-1-0716-2047-2_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Recent advances in pulsed electron paramagnetic resonance (EPR) spectroscopy enable studying structure and folding of nucleic acids. An efficient introduction of spin labels at specific positions within the oligonucleotide sequence is a prerequisite. We here present a step-by-step guide to synthesize long RNA oligonucleotides bearing spin labels at specific positions within the sequence. RNA preparation is achieved enzymatically via in vitro transcription using an expanded genetic alphabet. Highly structured, several hundred nucleotides long RNAs with two nitroxide spin labels at specific positions can be prepared by this method.
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6
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Bartosik K, Debiec K, Czarnecka A, Sochacka E, Leszczynska G. Synthesis of Nucleobase-Modified RNA Oligonucleotides by Post-Synthetic Approach. Molecules 2020; 25:E3344. [PMID: 32717917 PMCID: PMC7436257 DOI: 10.3390/molecules25153344] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 07/15/2020] [Accepted: 07/20/2020] [Indexed: 12/12/2022] Open
Abstract
The chemical synthesis of modified oligoribonucleotides represents a powerful approach to study the structure, stability, and biological activity of RNAs. Selected RNA modifications have been proven to enhance the drug-like properties of RNA oligomers providing the oligonucleotide-based therapeutic agents in the antisense and siRNA technologies. The important sites of RNA modification/functionalization are the nucleobase residues. Standard phosphoramidite RNA chemistry allows the site-specific incorporation of a large number of functional groups to the nucleobase structure if the building blocks are synthetically obtainable and stable under the conditions of oligonucleotide chemistry and work-up. Otherwise, the chemically modified RNAs are produced by post-synthetic oligoribonucleotide functionalization. This review highlights the post-synthetic RNA modification approach as a convenient and valuable method to introduce a wide variety of nucleobase modifications, including recently discovered native hypermodified functional groups, fluorescent dyes, photoreactive groups, disulfide crosslinks, and nitroxide spin labels.
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Affiliation(s)
| | | | | | | | - Grazyna Leszczynska
- Institute of Organic Chemistry, Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland; (K.B.); (K.D.); (A.C.); (E.S.)
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7
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Domnick C, Eggert F, Wuebben C, Bornewasser L, Hagelueken G, Schiemann O, Kath‐Schorr S. EPR Distance Measurements on Long Non-coding RNAs Empowered by Genetic Alphabet Expansion Transcription. Angew Chem Int Ed Engl 2020; 59:7891-7896. [PMID: 31981397 PMCID: PMC7318606 DOI: 10.1002/anie.201916447] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 01/22/2020] [Indexed: 11/26/2022]
Abstract
We present herein a novel nitroxide spin label-containing RNA triphosphate TPT3NO and its application for site-specific spin-labeling of RNA through in vitro transcription using an expanded genetic alphabet. Our strategy allows the facile preparation of spin-labeled RNAs with sizes ranging from short RNA oligonucleotides to large, complex RNA molecules with over 370 nucleotides by standard in vitro transcription. As a proof of concept, inter-spin distance distributions are measured by pulsed electron paramagnetic resonance (EPR) spectroscopy in short self-complementary RNA sequences and in a well-studied 185 nucleotide non-coding RNA, the B. subtilis glmS ribozyme. The approach is then applied to probe for the first time the folding of the 377 nucleotide A-region of the long non-coding RNA Xist, by PELDOR.
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Affiliation(s)
- Christof Domnick
- Life & Medical Sciences InstituteChemical Biology & Medicinal Chemistry UnitUniversity of BonnGerhard-Domagk-Str. 153121BonnGermany
| | - Frank Eggert
- Life & Medical Sciences InstituteChemical Biology & Medicinal Chemistry UnitUniversity of BonnGerhard-Domagk-Str. 153121BonnGermany
| | - Christine Wuebben
- Institute for Physical and Theoretical ChemistryUniversity of BonnWegelerstr. 1253115BonnGermany
| | - Lisa Bornewasser
- Life & Medical Sciences InstituteChemical Biology & Medicinal Chemistry UnitUniversity of BonnGerhard-Domagk-Str. 153121BonnGermany
| | - Gregor Hagelueken
- Institute for Physical and Theoretical ChemistryUniversity of BonnWegelerstr. 1253115BonnGermany
| | - Olav Schiemann
- Institute for Physical and Theoretical ChemistryUniversity of BonnWegelerstr. 1253115BonnGermany
| | - Stephanie Kath‐Schorr
- Life & Medical Sciences InstituteChemical Biology & Medicinal Chemistry UnitUniversity of BonnGerhard-Domagk-Str. 153121BonnGermany
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8
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Domnick C, Eggert F, Wuebben C, Bornewasser L, Hagelueken G, Schiemann O, Kath‐Schorr S. EPR Distance Measurements on Long Non‐coding RNAs Empowered by Genetic Alphabet Expansion Transcription. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201916447] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Christof Domnick
- Life & Medical Sciences Institute Chemical Biology & Medicinal Chemistry Unit University of Bonn Gerhard-Domagk-Str. 1 53121 Bonn Germany
| | - Frank Eggert
- Life & Medical Sciences Institute Chemical Biology & Medicinal Chemistry Unit University of Bonn Gerhard-Domagk-Str. 1 53121 Bonn Germany
| | - Christine Wuebben
- Institute for Physical and Theoretical Chemistry University of Bonn Wegelerstr. 12 53115 Bonn Germany
| | - Lisa Bornewasser
- Life & Medical Sciences Institute Chemical Biology & Medicinal Chemistry Unit University of Bonn Gerhard-Domagk-Str. 1 53121 Bonn Germany
| | - Gregor Hagelueken
- Institute for Physical and Theoretical Chemistry University of Bonn Wegelerstr. 12 53115 Bonn Germany
| | - Olav Schiemann
- Institute for Physical and Theoretical Chemistry University of Bonn Wegelerstr. 12 53115 Bonn Germany
| | - Stephanie Kath‐Schorr
- Life & Medical Sciences Institute Chemical Biology & Medicinal Chemistry Unit University of Bonn Gerhard-Domagk-Str. 1 53121 Bonn Germany
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9
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Domnick C, Hagelueken G, Eggert F, Schiemann O, Kath-Schorr S. Posttranscriptional spin labeling of RNA by tetrazine-based cycloaddition. Org Biomol Chem 2019; 17:1805-1808. [DOI: 10.1039/c8ob02597e] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Spin labeling of in vitro transcribed RNA by iEDDA click chemistry is demonstrated. This allows the determination of distance distributions between two nitroxide spin labels by PELDOR in a self-complementary RNA duplex.
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Affiliation(s)
- Christof Domnick
- Life & Medical Sciences Institute
- Chemical Biology & Medicinal Chemistry Unit
- University of Bonn
- 53121 Bonn
- Germany
| | - Gregor Hagelueken
- Institute for Physical and Theoretical Chemistry
- University of Bonn
- 53115 Bonn
- Germany
| | - Frank Eggert
- Life & Medical Sciences Institute
- Chemical Biology & Medicinal Chemistry Unit
- University of Bonn
- 53121 Bonn
- Germany
| | - Olav Schiemann
- Institute for Physical and Theoretical Chemistry
- University of Bonn
- 53115 Bonn
- Germany
| | - Stephanie Kath-Schorr
- Life & Medical Sciences Institute
- Chemical Biology & Medicinal Chemistry Unit
- University of Bonn
- 53121 Bonn
- Germany
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10
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Gmeiner C, Dorn G, Allain FHT, Jeschke G, Yulikov M. Spin labelling for integrative structure modelling: a case study of the polypyrimidine-tract binding protein 1 domains in complexes with short RNAs. Phys Chem Chem Phys 2018; 19:28360-28380. [PMID: 29034946 DOI: 10.1039/c7cp05822e] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A combined method, employing NMR and EPR spectroscopies, has demonstrated its strength in solving structures of protein/RNA and other types of biomolecular complexes. This method works particularly well when the large biomolecular complex consists of a limited number of rigid building blocks, such as RNA-binding protein domains (RBDs). A variety of spin labels is available for such studies, allowing for conventional as well as spectroscopically orthogonal double electron-electron resonance (DEER) measurements in EPR. In this work, we compare different types of nitroxide-based and Gd(iii)-based spin labels attached to isolated RBDs of the polypyrimidine-tract binding protein 1 (PTBP1) and to short RNA fragments. In particular, we demonstrate experiments on spectroscopically orthogonal labelled RBD/RNA complexes. For all experiments we analyse spin labelling, DEER method performance, resulting distance distributions, and their consistency with the predictions from the spin label rotamers analysis. This work provides a set of intra-domain calibration DEER data, which can serve as a basis to start structure determination of the full length PTBP1 complex with an RNA derived from encephalomycarditis virus (EMCV) internal ribosomal entry site (IRES). For a series of tested labelling sites, we discuss their particular advantages and drawbacks in such a structure determination approach.
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Affiliation(s)
- Christoph Gmeiner
- Laboratory of Physical Chemistry, ETH Zurich, Zurich, 8093, Switzerland.
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11
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Kath-Schorr S. Cycloadditions for Studying Nucleic Acids. Top Curr Chem (Cham) 2015; 374:4. [PMID: 27572987 DOI: 10.1007/s41061-015-0004-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 11/30/2015] [Indexed: 12/13/2022]
Abstract
Cycloaddition reactions for site-specific or global modification of nucleic acids have enabled the preparation of a plethora of previously inaccessible DNA and RNA constructs for structural and functional studies on naturally occurring nucleic acids, the assembly of nucleic acid nanostructures, therapeutic applications, and recently, the development of novel aptamers. In this chapter, recent progress in nucleic acid functionalization via a range of different cycloaddition (click) chemistries is presented. At first, cycloaddition/click chemistries already used for modifying nucleic acids are summarized, ranging from the well-established copper(I)-catalyzed alkyne-azide cycloaddition reaction to copper free methods, such as the strain-promoted azide-alkyne cycloaddition, tetrazole-based photoclick chemistry and the inverse electron demand Diels-Alder cycloaddition reaction between strained alkenes and tetrazine derivatives. The subsequent sections contain selected applications of nucleic acid functionalization via click chemistry; in particular, site-specific enzymatic labeling in vitro, either via DNA and RNA recognizing enzymes or by introducing unnatural base pairs modified for click reactions. Further sections report recent progress in metabolic labeling and fluorescent detection of DNA and RNA synthesis in vivo, click nucleic acid ligation, click chemistry in nanostructure assembly and click-SELEX as a novel method for the selection of aptamers.
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Affiliation(s)
- Stephanie Kath-Schorr
- LIMES Institute, Chemical Biology and Medicinal Chemistry Unit, University of Bonn, Bonn, Germany.
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12
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Endeward B, Marko A, Denysenkov VP, Sigurdsson ST, Prisner TF. Advanced EPR Methods for Studying Conformational Dynamics of Nucleic Acids. Methods Enzymol 2015; 564:403-25. [PMID: 26477259 DOI: 10.1016/bs.mie.2015.06.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Pulsed electron paramagnetic resonance (EPR) spectroscopy has become an important tool for structural characterization of biomolecules allowing measurement of the distances between two paramagnetic spin labels attached to a biomolecule in the 2-8 nm range. In this chapter, we will focus on applications of this approach to investigate tertiary structure elements as well as conformational dynamics of nucleic acid molecules. Both aspects take advantage of using specific spin labels that are rigidly attached to the nucleobases, as they allow obtaining not only the distance but also the relative orientation between both nitroxide moieties with high accuracy. Thus, not only the distance but additionally the three Euler angles between both the nitroxide axis systems and the two polar angles of the interconnecting vector with respect to the nitroxide axis systems can be extracted from a single pair of spin labels. To extract all these parameters independently and unambiguously, a set of multifrequency/multifield pulsed EPR experiments have to be performed. We will describe the experimental procedure as well as newly developed spin labels, which are helpful to disentangle all these parameters, and tools which we have developed to analyze such data sets. The procedures and analyses will be illustrated by examples from our laboratory.
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Affiliation(s)
- B Endeward
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - A Marko
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - V P Denysenkov
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - S Th Sigurdsson
- Department of Chemistry, Science Institute, University of Iceland, Reykjavık, Iceland
| | - T F Prisner
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Frankfurt am Main, Germany.
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13
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Gophane DB, Sigurdsson ST. TEMPO-derived spin labels linked to the nucleobases adenine and cytosine for probing local structural perturbations in DNA by EPR spectroscopy. Beilstein J Org Chem 2015; 11:219-27. [PMID: 25815073 PMCID: PMC4362019 DOI: 10.3762/bjoc.11.24] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 01/15/2015] [Indexed: 02/04/2023] Open
Abstract
Three 2´-deoxynucleosides containing semi-flexible spin labels, namely (T)A, (U)A and (U)C, were prepared and incorporated into deoxyoligonucleotides using the phosphoramidite method. All three nucleosides contain 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) connected to the exocyclic amino group; (T)A directly and (U)A as well as (U)C through a urea linkage. (T)A and (U)C showed a minor destabilization of a DNA duplex, as registered by a small decrease in the melting temperature, while (U)A destabilized the duplex by more than 10 °C. Circular dichroism (CD) measurements indicated that all three labels were accommodated in B-DNA duplex. The mobility of the spin label (T)A varied with different base-pairing partners in duplex DNA, with the (T)A•T pair being the least mobile. Furthermore, (T)A showed decreased mobility under acidic conditions for the sequences (T)A•C and (T)A•G, to the extent that the EPR spectrum of the latter became nearly superimposable to that of (T)A•T. The reduced mobility of the (T)A•C and (T)A•G mismatches at pH 5 is consistent with the formation of (T)AH(+)•C and (T)AH(+)•G, in which protonation of N1 of A allows the formation of an additional hydrogen bond to N3 of C and N7 of G, respectively, with G in a syn-conformation. The urea-based spin labels (U)A and (U)C were more mobile than (T)A, but still showed a minor variation in their EPR spectra when paired with A, G, C or T in a DNA duplex. (U)A and (U)C had similar mobility order for the different base pairs, with the lowest mobility when paired with C and the highest when paired with T.
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Affiliation(s)
- Dnyaneshwar B Gophane
- University of Iceland, Department of Chemistry, Science Institute, Dunhaga 3, 107 Reykjavik, Iceland
| | - Snorri Th Sigurdsson
- University of Iceland, Department of Chemistry, Science Institute, Dunhaga 3, 107 Reykjavik, Iceland
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14
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Wicke L, Engels JW. An unexpected methyl group migration during on-column Stille derivatization of RNA. Tetrahedron 2014. [DOI: 10.1016/j.tet.2013.11.061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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15
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Romainczyk O, Elduque X, Engels JW. Attachment of Nitroxide Spin Labels to Nucleic Acids for EPR. ACTA ACUST UNITED AC 2012; Chapter 7:Unit7.17. [DOI: 10.1002/0471142700.nc0717s49] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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16
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Abstract
Stille Coupling is a versatile C-C bond forming reaction with high functional group tolerance under mild conditions. Our on column synthesis concept for RNA modification is based on the incorporation of iodo substituted nucleotide precursors to RNA during automated standard solid phase synthesis via TBDMS-, TC-, and ACE- protecting group strategies. Subsequently, the RNA, still bound on solid support, is ready for orthogonal postsynthetic functionalization via Stille cross-couplings utilizing the advantages of solid phase synthesis. Several monomer test reactions were employed with 2-iodo adenosine and 5-iodo uridine and organostannanes as coupling partners under different conditions, changing the catalyst/ligand system, temperature, and reaction time as well as conventional heating and microwave irradiation. Finally, Stille cross-couplings under optimized conditions were transferred to fully protected 5-mer and 12-mer RNA oligonucleotides on-column. Deprotection and cleavage from solid support resulted in site-specifically labeled oligonucleotides. Derivatizations via Stille cross-couplings were performed initially with vinyltributylstannane as well as later with 2-furanyl-, 2-thiophene-, and benzothiophene-2-tributylstannanes yielding fluorescently functionalized RNA.
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Affiliation(s)
- Lena Wicke
- Institute for Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe University, Max-von-Laue Strasse 7, 60438 Frankfurt am Main, Germany
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17
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Studying biomolecular complexes with pulsed electron–electron double resonance spectroscopy. Biochem Soc Trans 2011; 39:128-39. [DOI: 10.1042/bst0390128] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The function of biomolecules is intrinsically linked to their structure and the complexes they form during function. Techniques for the determination of structures and dynamics of these nanometre assemblies are therefore important for an understanding on the molecular level. PELDOR (pulsed electron–electron double resonance) is a pulsed EPR method that can be used to reliably and precisely measure distances in the range 1.5–8 nm, to unravel orientations and to determine the number of monomers in complexes. In conjunction with site-directed spin labelling, it can be applied to biomolecules of all sizes in aqueous solutions or membranes. PELDOR is therefore complementary to the methods of X-ray crystallography, NMR and FRET (fluorescence resonance energy transfer) and is becoming a powerful method for structural determination of biomolecules. In the present review, the methods of PELDOR are discussed and examples where PELDOR has been used to obtain structural information on biomolecules are summarized.
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18
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Krstić I, Endeward B, Margraf D, Marko A, Prisner TF. Structure and dynamics of nucleic acids. Top Curr Chem (Cham) 2011; 321:159-98. [PMID: 22160388 DOI: 10.1007/128_2011_300] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In this chapter we describe the application of CW and pulsed EPR methods for the investigation of structural and dynamical properties of RNA and DNA molecules and their interaction with small molecules and proteins. Special emphasis will be given to recent applications of dipolar spectroscopy on nucleic acids.
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Affiliation(s)
- Ivan Krstić
- Goethe University Frankfurt, Frankfurt am Main, Germany
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Kuznetsov NA, Milov AD, Isaev NP, Vorobjev YN, Koval VV, Dzuba SA, Fedorova OS, Tsvetkov YD. PELDOR analysis of enzyme-induced structural changes in damaged DNA duplexes. MOLECULAR BIOSYSTEMS 2011; 7:2670-80. [DOI: 10.1039/c1mb05189j] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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20
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Wunnicke D, Strohbach D, Weigand JE, Appel B, Feresin E, Suess B, Müller S, Steinhoff HJ. Ligand-induced conformational capture of a synthetic tetracycline riboswitch revealed by pulse EPR. RNA (NEW YORK, N.Y.) 2011; 17:182-8. [PMID: 21097555 PMCID: PMC3004059 DOI: 10.1261/rna.2222811] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 10/27/2010] [Indexed: 05/22/2023]
Abstract
RNA aptamers are in vitro-selected binding domains that recognize their respective ligand with high affinity and specificity. They are characterized by complex three-dimensional conformations providing preformed binding pockets that undergo conformational changes upon ligand binding. Small molecule-binding aptamers have been exploited as synthetic riboswitches for conditional gene expression in various organisms. In the present study, double electron-electron resonance (DEER) spectroscopy combined with site-directed spin labeling was used to elucidate the conformational transition of a tetracycline aptamer upon ligand binding. Different sites were selected for post-synthetic introduction of either the (1-oxyl-2,2,5,5-tetramethylpyrroline-3-methyl) methanethiosulfonate by reaction with a 4-thiouridine modified RNA or of 4-isocyanato-2,6-tetramethylpiperidyl-N-oxid spin label by reaction with 2'-aminouridine modified RNA. The results of the DEER experiments indicate the presence of a thermodynamic equilibrium between two aptamer conformations in the free state and capture of one conformation upon tetracycline binding.
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Affiliation(s)
- Dorith Wunnicke
- Fachbereich Physik, Universität Osnabrück, 49069 Osnabrück, Germany
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21
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Wachowius F, Höbartner C. Chemical RNA modifications for studies of RNA structure and dynamics. Chembiochem 2010; 11:469-80. [PMID: 20135663 DOI: 10.1002/cbic.200900697] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Falk Wachowius
- Research Group Nucleic Acid Chemistry, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
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22
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Klare JP, Steinhoff HJ. Spin labeling EPR. PHOTOSYNTHESIS RESEARCH 2009; 102:377-390. [PMID: 19728138 DOI: 10.1007/s11120-009-9490-7] [Citation(s) in RCA: 169] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2008] [Accepted: 08/14/2009] [Indexed: 05/28/2023]
Abstract
Site-directed spin labeling in combination with electron paramagnetic resonance spectroscopy has emerged as an efficient tool to elucidate the structure and conformational dynamics of biomolecules under native-like conditions. This article summarizes the basics as well as recent progress of site-directed spin labeling. Continuous wave EPR spectra analyses and pulse EPR techniques are reviewed with special emphasis on applications to the sensory rhodopsin-transducer complex mediating the photophobic response of the halophilic archaeum Natronomonas pharaonis and the photosynthetic reaction center from Rhodobacter sphaeroides R26.
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Affiliation(s)
- Johann P Klare
- Physics Department, University of Osnabrück, Barbarastr. 7, 49076, Osnabrück, Germany
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23
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Kuznetsov NA, Milov AD, Koval VV, Samoilova RI, Grishin YA, Knorre DG, Tsvetkov YD, Fedorova OS, Dzuba SA. PELDOR study of conformations of double-spin-labeled single- and double-stranded DNA with non-nucleotide inserts. Phys Chem Chem Phys 2009; 11:6826-32. [PMID: 19639157 DOI: 10.1039/b904873a] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
DNA fragments were synthesized consisting of 12 nucleotides and containing non-nucleotide inserts of different length in the middle. Two nitroxide spin labels 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl were attached at the two ends of the molecules. Single-stranded DNAs and double-stranded DNAs (DNA duplexes) in frozen at 77 K glassy water/glycerol solutions were studied using pulsed electron-electron double resonance (PELDOR). The distance distributions between two spin labels in molecules were obtained from PELDOR data using Tikhonov regularization algorithm, and were found to be close to the Gaussian functions. Experimental PELDOR data were fitted by adjusting precisely the maximum position and the width of these functions. The obtained results show that duplexes possess a substantially narrower distribution, as compared to the single-stranded DNAs. Introduction of a non-nucleotide insert 2-hydroxymethyl-3-hydroxy-tetrahydrofuran leads to a slight but nevertheless detectable decrease of the mean distance between two spin labels. This decrease may be attributed to bending of the molecule around the insert site, by an angle of approximately 20 degrees . An introduction of a non-nucleotide insert bis-(di-ethyleneglycol)-phosphate results in a remarkable broadening of the distance distribution. The results evidence that PELDOR of spin-labeled DNA molecules may be used as a "molecular ruler" for studying the influence of local damages on the DNA conformations.
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Affiliation(s)
- Nikita A Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, Lavrentyev Ave. 8, 630090, Novosibirsk, Russia
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24
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Obeid S, Yulikov M, Jeschke G, Marx A. Enzymatic synthesis of multiple spin-labeled DNA. Angew Chem Int Ed Engl 2008; 47:6782-5. [PMID: 18671226 DOI: 10.1002/anie.200802314] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Samra Obeid
- Department of Chemistry and Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
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25
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Obeid S, Yulikov M, Jeschke G, Marx A. Enzymatische Synthese mehrfach spinmarkierter DNA. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200802314] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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26
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Frolow O, Bode BE, Engels JW. The synthesis of EPR differentiable spinlabels and their coupling to uridine. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2008; 26:655-9. [PMID: 18066874 DOI: 10.1080/15257770701490522] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
For EPR measurements of RNA, DNA, or proteins, the occurrence of the paramagnetic species is necessary. The aim of this work is to improve the synthesis of two different EPR spinlabels 2,2,6,6-tetra methyl-3,4-dehydro-piperidin-N-oxyl-4-acetylene (TEMPA) 6 and 15N-labeled TEMPA 6* and their coupling to uridine. The yield of the synthesis of TEMPA could be increased to 40% and the second nitroxide 2,2,6,6-tetramethyl-3,4-dehydro-piperidin-15N-oxyl-4-acetylene 6* could be synthesized with a yield of 11%.
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Affiliation(s)
- Olga Frolow
- Johann W. Goethe Universität Frankfurt am Main, Institut für Organische Chemie und Chemische Biologie, Frankfurt am Main, Germany
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27
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Ward R, Keeble DJ, El-Mkami H, Norman DG. Distance determination in heterogeneous DNA model systems by pulsed EPR. Chembiochem 2008; 8:1957-64. [PMID: 17886320 DOI: 10.1002/cbic.200700245] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Many biological systems, especially those based on nucleic acids, are structurally heterogeneous in solution. We demonstrate here the ability to measure multiple distances, of between 2 and 7 nm, from a heterogeneous mixture of double-spin-labeled DNA duplexes. We have constructed a DNA distance ruler based on the attachment of nitroxide spin labels to 2'-amino-modified nucleosides. The distribution of distances between the spin labels was obtained by Tikhonov regularization analysis of the dipolar coupling evolution data measured by using the electron paramagnetic resonance method, pulsed-electron double resonance (PELDOR). Optimization of the conditions and techniques used in the preparation of the samples has allowed us to increase the sensitivity and reduce aggregation artifacts. As a result, we have been able to demonstrate deconvolution of distances from structurally heterogeneous samples and show the limits of the technique by examining data derived from up to five DNA duplexes, in a single mixture, in which the concentration of each species was as low as 5 microM.
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Affiliation(s)
- Richard Ward
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
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28
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Sowa GZ, Qin PZ. Site-directed spin labeling studies on nucleic acid structure and dynamics. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2008; 82:147-97. [PMID: 18929141 DOI: 10.1016/s0079-6603(08)00005-6] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Site-directed spin labeling (SDSL) uses electron paramagnetic resonance (EPR) spectroscopy to monitor the behavior of a stable nitroxide radical attached at specific locations within a macromolecule such as protein, DNA, or RNA. Parameters obtained from EPR measurements, such as internitroxide distances and descriptions of the rotational motion of a nitroxide, provide unique information on features near the labeling site. With recent advances in solid-phase synthesis of nucleic acids and developments in EPR methodologies, particularly pulsed EPR technologies, SDSL has been increasingly used to study the structure and dynamics of DNA and RNA at the level of the individual nucleotides. This chapter summarizes the current SDSL studies on nucleic acids, with discussions focusing on literature from the last decade.
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Affiliation(s)
- Glenna Z Sowa
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
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29
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Yang Z, Becker J, Saxena S. On Cu(II)-Cu(II) distance measurements using pulsed electron electron double resonance. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2007; 188:337-43. [PMID: 17825593 DOI: 10.1016/j.jmr.2007.08.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Revised: 08/10/2007] [Accepted: 08/10/2007] [Indexed: 05/17/2023]
Abstract
The effects of orientational selectivity on the 4-pulse electron electron double resonance (PELDOR) ESR spectra of coupled Cu(II)-Cu(II) spins are presented. The data were collected at four magnetic fields on a poly-proline peptide containing two Cu(II) centers. The Cu(II)-PELDOR spectra of this peptide do not change appreciably with magnetic field at X-band. The data were analyzed by adapting the theory of Maryasov, Tsvetkov, and Raap [A.G. Maryasov, Y.D. Tsvetkov, J. Raap, Weakly coupled radical pairs in solids:ELDOR in ESE structure studies, Appl. Magn. Reson. 14 (1998) 101-113]. Simulations indicate that orientational effects are important for Cu(II)-PELDOR. Based on simulations, the field-independence of the PELDOR data for this peptide is likely due to two effects. First, for this peptide, the Cu(II) g-tensor(s) are in a very specific orientation with respect to the interspin vector. Second, the flexibility of the peptide washes out the orientation effects. These effects reduce the suitability of the poly-proline based peptide as a good model system to experimentally probe orientational effects in such experiments. An average Cu(II)-Cu(II) distance of 2.1-2.2 nm was determined, which is consistent with earlier double quantum coherence ESR results.
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Affiliation(s)
- Zhongyu Yang
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
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30
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Cai Q, Kusnetzow AK, Hideg K, Price EA, Haworth IS, Qin PZ. Nanometer distance measurements in RNA using site-directed spin labeling. Biophys J 2007; 93:2110-7. [PMID: 17526583 PMCID: PMC1959523 DOI: 10.1529/biophysj.107.109439] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Accepted: 05/18/2007] [Indexed: 11/18/2022] Open
Abstract
The method of site-directed spin labeling (SDSL) utilizes a stable nitroxide radical to obtain structural and dynamic information on biomolecules. Measuring dipolar interactions between pairs of nitroxides yields internitroxide distances, from which quantitative structural information can be derived. This study evaluates SDSL distance measurements in RNA using a nitroxide probe, designated as R5, which is attached in an efficient and cost-effective manner to backbone phosphorothioate sites that are chemically substituted in arbitrary sequences. It is shown that R5 does not perturb the global structure of the A-form RNA helix. Six sets of internitroxide distances, ranging from 20 to 50 A, were measured on an RNA duplex with a known X-ray crystal structure. The measured distances strongly correlate (R(2) = 0.97) with those predicted using an efficient algorithm for determining the expected internitroxide distances from the parent RNA structure. The results enable future studies of global RNA structures for which high-resolution structural data are absent.
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Affiliation(s)
- Qi Cai
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089-0744, USA
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31
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Price EA, Sutch BT, Cai Q, Qin PZ, Haworth IS. Computation of nitroxide-nitroxide distances in spin-labeled DNA duplexes. Biopolymers 2007; 87:40-50. [PMID: 17538992 PMCID: PMC2430107 DOI: 10.1002/bip.20769] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Nanometer distances in nucleic acids can be measured by EPR using two 1-oxyl-2,2,5,5-tetramethylpyrroline radicals, with each label attached via a methylene group to a phosphorothioate-substituted backbone position as one of two phosphorothioate diastereomers (R(P) and S(P)). Correlating the internitroxide distance to the geometry of the parent molecule requires computational analysis of the label conformers. Here, we report sixteen 4-ns MD simulations on a DNA duplex d(CTACTGCTTTAG) .d(CTAAAGCAGTAG) with label pairs at C7/C19, T5/A17, and T2/T14, respectively. For each labeled duplex, four simulations were performed with S(P)/S(P), R(P)/R(P), S(P)/R(P), and R(P)/S(P) labels, with initial all trans label conformations. Another set of four simulations was performed for the 7/19-labeled duplex using a different label starting conformation. The average internitroxide distance r(MD) was within 0.2 A for the two sets of simulations for the 7/19-labeled duplex, indicating sufficient sampling of conformational space. For all three labeled duplexes studied, r(MD) agreed with experimental values, as well as with average distances obtained from an efficient conformer search algorithm (NASNOX). The simulations also showed that the labels have conformational preferences determined by the linker chemistry and label-DNA interactions. These results establish computational algorithms that allow use of the 1-oxyl-2,2,5,5-tetramethylpyrroline label for mapping global structures of nucleic acids.
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Affiliation(s)
- Eric A. Price
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089-0744
| | - Brian T. Sutch
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90089-9121
| | - Qi Cai
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089-0744
| | - Peter Z. Qin
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089-0744
| | - Ian S. Haworth
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90089-9121
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32
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Schiemann O, Piton N, Plackmeyer J, Bode BE, Prisner TF, Engels JW. Spin labeling of oligonucleotides with the nitroxide TPA and use of PELDOR, a pulse EPR method, to measure intramolecular distances. Nat Protoc 2007; 2:904-23. [PMID: 17446891 DOI: 10.1038/nprot.2007.97] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In this protocol, we describe the facile synthesis of the nitroxide spin-label 2,2,5,5-tetramethyl-pyrrolin-1-oxyl-3-acetylene (TPA) and then its coupling to DNA/RNA through Sonogashira cross-coupling during automated solid-phase synthesis. Subsequently, we explain how to perform distance measurements between two such spin-labels on RNA/DNA using the pulsed electron paramagnetic resonance method pulsed electron double resonance (PELDOR). This combination of methods can be used to study global structure elements of oligonucleotides in frozen solution at RNA/DNA amounts of approximately 10 nmol. We especially focus on the Sonogashira cross-coupling step, the advantages of the ACE chemistry together with the appropriate parameters for the RNA synthesizer and on the PELDOR data analysis. This procedure is applicable to RNA/DNA strands of up to approximately 80 bases in length and PELDOR yields reliably spin-spin distances up to approximately 6.5 nm. The synthesis of TPA takes approximately 5 days and spin labeling together with purification approximately 4 days. The PELDOR measurements usually take approximately 16 h and data analysis from an hour up to several days depending on the extent of analysis.
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Affiliation(s)
- Olav Schiemann
- Institute of Physical and Theoretical Chemistry, Center for Biomolecular Magnetic Resonance, Frankfurt am Main, Germany.
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33
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Schiemann O, Prisner TF. Long-range distance determinations in biomacromolecules by EPR spectroscopy. Q Rev Biophys 2007; 40:1-53. [PMID: 17565764 DOI: 10.1017/s003358350700460x] [Citation(s) in RCA: 428] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Electron paramagnetic resonance (EPR) spectroscopy provides a variety of tools to study structures and structural changes of large biomolecules or complexes thereof. In order to unravel secondary structure elements, domain arrangements or complex formation, continuous wave and pulsed EPR methods capable of measuring the magnetic dipole coupling between two unpaired electrons can be used to obtain long-range distance constraints on the nanometer scale. Such methods yield reliably and precisely distances of up to 80 A, can be applied to biomolecules in aqueous buffer solutions or membranes, and are not size limited. They can be applied either at cryogenic or physiological temperatures and down to amounts of a few nanomoles. Spin centers may be metal ions, metal clusters, cofactor radicals, amino acid radicals, or spin labels. In this review, we discuss the advantages and limitations of the different EPR spectroscopic methods, briefly describe their theoretical background, and summarize important biological applications. The main focus of this article will be on pulsed EPR methods like pulsed electron-electron double resonance (PELDOR) and their applications to spin-labeled biosystems.
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Affiliation(s)
- Olav Schiemann
- Institute of Physical and Theoretical Chemistry, Center for Biomolecular Magnetic Resonance, J. W. Goethe-University Frankfurt, 60438 Frankfurt am Main, Germany.
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Bode BE, Margraf D, Plackmeyer J, Dürner G, Prisner TF, Schiemann O. Counting the Monomers in Nanometer-Sized Oligomers by Pulsed Electron−Electron Double Resonance. J Am Chem Soc 2007; 129:6736-45. [PMID: 17487970 DOI: 10.1021/ja065787t] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In a lot of cases active biomolecules are complexes of higher order, thus methods capable of counting the number of building blocks and elucidating their geometric arrangement are needed. Therefore, we experimentally validate here spin-counting via 4-pulse electron-electron double resonance (PELDOR) on well-defined test samples. Two biradicals, a symmetric and an asymmetric triradical, and a tetraradical were synthesized in a convergent reaction scheme via palladium-catalyzed cross-coupling reactions. PELDOR was then used to obtain geometric information and the number of spin centers per molecule in a single experiment. The measurement yielded the expected distances (2.2-3.8 nm) and showed that different spin-spin distances in one molecule can be resolved even if the difference amounts to only 5 A. The number of spins n has been determined to be 2.1 in both biradicals, to 3.1 and 3.0 in the symmetric and asymmetric triradicals, respectively, and to 3.9 in the tetraradical. The overall error of PELDOR spin-counting was found to be 5% for up to four spins. Thus, this method is a valuable tool to determine the number of constituting spin-bearing monomers in biologically relevant homo- and heterooligomers and how their oligomerization state and geometric arrangement changes during function.
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Affiliation(s)
- Bela E Bode
- Institute of Physical and Theoretical Chemistry, Center for Biomolecular Magnetic Resonance, J. W. Goethe-University, Frankfurt am Main, Germany
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35
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Piton N, Mu Y, Stock G, Prisner TF, Schiemann O, Engels JW. Base-specific spin-labeling of RNA for structure determination. Nucleic Acids Res 2007; 35:3128-43. [PMID: 17452362 PMCID: PMC1891445 DOI: 10.1093/nar/gkm169] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
To facilitate the measurement of intramolecular distances in solvated RNA systems, a combination of spin-labeling, electron paramagnetic resonance (EPR), and molecular dynamics (MD) simulation is presented. The fairly rigid spin label 2,2,5,5-tetramethyl-pyrrolin-1-yloxyl-3-acetylene (TPA) was base and site specifically introduced into RNA through a Sonogashira palladium catalyzed cross-coupling on column. For this purpose 5-iodo-uridine, 5-iodo-cytidine and 2-iodo-adenosine phosphoramidites were synthesized and incorporated into RNA-sequences. Application of the recently developed ACE chemistry presented the main advantage to limit the reduction of the nitroxide to an amine during the oligonucleotide automated synthesis and thus to increase substantially the reliability of the synthesis and the yield of labeled oligonucleotides. 4-Pulse Electron Double Resonance (PELDOR) was then successfully used to measure the intramolecular spin-spin distances in six doubly labeled RNA-duplexes. Comparison of these results with our previous work on DNA showed that A- and B-Form can be differentiated. Using an all-atom force field with explicit solvent, MD simulations gave results in good agreement with the measured distances and indicated that the RNA A-Form was conserved despite a local destabilization effect of the nitroxide label. The applicability of the method to more complex biological systems is discussed.
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Affiliation(s)
- Nelly Piton
- Institute of Organic Chemistry and Chemical Biology, J. W. Goethe-University, Max-von-Laue Strasse 7, 60438 Frankfurt am Main, Germany, Institute of Physical and Theoretical Chemistry, J. W. Goethe-University, Max-von-Laue Strasse 7, 60438 Frankfurt am Main, Germany and Center of Biological Magnetic Resonance, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Yuguang Mu
- Institute of Organic Chemistry and Chemical Biology, J. W. Goethe-University, Max-von-Laue Strasse 7, 60438 Frankfurt am Main, Germany, Institute of Physical and Theoretical Chemistry, J. W. Goethe-University, Max-von-Laue Strasse 7, 60438 Frankfurt am Main, Germany and Center of Biological Magnetic Resonance, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Gerhard Stock
- Institute of Organic Chemistry and Chemical Biology, J. W. Goethe-University, Max-von-Laue Strasse 7, 60438 Frankfurt am Main, Germany, Institute of Physical and Theoretical Chemistry, J. W. Goethe-University, Max-von-Laue Strasse 7, 60438 Frankfurt am Main, Germany and Center of Biological Magnetic Resonance, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Thomas F. Prisner
- Institute of Organic Chemistry and Chemical Biology, J. W. Goethe-University, Max-von-Laue Strasse 7, 60438 Frankfurt am Main, Germany, Institute of Physical and Theoretical Chemistry, J. W. Goethe-University, Max-von-Laue Strasse 7, 60438 Frankfurt am Main, Germany and Center of Biological Magnetic Resonance, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Olav Schiemann
- Institute of Organic Chemistry and Chemical Biology, J. W. Goethe-University, Max-von-Laue Strasse 7, 60438 Frankfurt am Main, Germany, Institute of Physical and Theoretical Chemistry, J. W. Goethe-University, Max-von-Laue Strasse 7, 60438 Frankfurt am Main, Germany and Center of Biological Magnetic Resonance, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Joachim W. Engels
- Institute of Organic Chemistry and Chemical Biology, J. W. Goethe-University, Max-von-Laue Strasse 7, 60438 Frankfurt am Main, Germany, Institute of Physical and Theoretical Chemistry, J. W. Goethe-University, Max-von-Laue Strasse 7, 60438 Frankfurt am Main, Germany and Center of Biological Magnetic Resonance, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
- *To whom correspondence should be addressed.+49-69-798-29150+49-69-798-29148 Correspondence may also be addressed to Olav Schiemann. +49-69-798-29786+49-69-798-29404
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36
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Cai Q, Kusnetzow AK, Hubbell WL, Haworth IS, Gacho GPC, Van Eps N, Hideg K, Chambers EJ, Qin PZ. Site-directed spin labeling measurements of nanometer distances in nucleic acids using a sequence-independent nitroxide probe. Nucleic Acids Res 2006; 34:4722-30. [PMID: 16966338 PMCID: PMC1635252 DOI: 10.1093/nar/gkl546] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Revised: 06/30/2006] [Accepted: 07/13/2006] [Indexed: 11/12/2022] Open
Abstract
In site-directed spin labeling (SDSL), local structural and dynamic information is obtained via electron paramagnetic resonance (EPR) spectroscopy of a stable nitroxide radical attached site-specifically to a macromolecule. Analysis of electron spin dipolar interactions between pairs of nitroxides yields the inter-nitroxide distance, which provides quantitative structural information. The development of pulse EPR methods has enabled such distance measurements up to 70 A in bio-molecules, thus opening up the possibility of SDSL global structural mapping. This study evaluates SDSL distance measurement using a nitroxide (designated as R5) that can be attached, in an efficient and cost-effective manner, to a phosphorothioate backbone position at arbitrary DNA or RNA sequences. R5 pairs were attached to selected positions of a dodecamer DNA duplex with a known NMR structure, and eight distances, ranging from 20 to 40 A, were measured using double electron-electron resonance (DEER). The measured distances correlated strongly (R2 = 0.98) with the predicted values calculated based on a search of sterically allowable R5 conformations in the NMR structure, thus demonstrating accurate distance measurements using R5. Furthermore, distance measurement in a 42 kD DNA was demonstrated. The results establish R5 as a sequence-independent probe for global structural mapping of DNA and DNA-protein complexes.
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Affiliation(s)
- Qi Cai
- Department of Chemistry , University of Southern CaliforniaLos Angeles, CA 90089-0744, USA
| | - Ana Karin Kusnetzow
- Jules Stein Eye Institute and Department of Chemistry and Biochemistry, University of CaliforniaLos Angeles, CA 90095, USA
| | - Wayne L. Hubbell
- Jules Stein Eye Institute and Department of Chemistry and Biochemistry, University of CaliforniaLos Angeles, CA 90095, USA
| | - Ian S. Haworth
- Department of Pharmaceutical Sciences, University of Southern CaliforniaLos Angeles, CA 90089, USA
| | - Gian Paola C. Gacho
- Department of Chemistry , University of Southern CaliforniaLos Angeles, CA 90089-0744, USA
| | - Ned Van Eps
- Jules Stein Eye Institute and Department of Chemistry and Biochemistry, University of CaliforniaLos Angeles, CA 90095, USA
| | - Kálmán Hideg
- Institute of Organic and Medical Chemistry, University of PécsH-7643, Pécs, P.O. Box 99, Hungary
| | - Eric J. Chambers
- Department of Pharmaceutical Sciences, University of Southern CaliforniaLos Angeles, CA 90089, USA
| | - Peter Z. Qin
- Department of Chemistry , University of Southern CaliforniaLos Angeles, CA 90089-0744, USA
- Department of Biological Sciences, University of Southern CaliforniaLos Angeles, CA 90089-0744, USA
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