1
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Gauger M, Heinz M, Halbritter ALJ, Stelzl LS, Erlenbach N, Hummer G, Sigurdsson ST, Prisner TF. Structure and Internal Dynamics of Short RNA Duplexes Determined by a Combination of Pulsed EPR Methods and MD Simulations. Angew Chem Int Ed Engl 2024; 63:e202402498. [PMID: 38530284 DOI: 10.1002/anie.202402498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 03/24/2024] [Accepted: 03/25/2024] [Indexed: 03/27/2024]
Abstract
We used EPR spectroscopy to characterize the structure of RNA duplexes and their internal twist, stretch and bending motions. We prepared eight 20-base-pair-long RNA duplexes containing the rigid spin-label Çm, a cytidine analogue, at two positions and acquired orientation-selective PELDOR/DEER data. By using different frequency bands (X-, Q-, G-band), detailed information about the distance and orientation of the labels was obtained and provided insights into the global conformational dynamics of the RNA duplex. We used 19F Mims ENDOR experiments on three singly Çm- and singly fluorine-labeled RNA duplexes to determine the exact position of the Çm spin label in the helix. In a quantitative comparison to MD simulations of RNA with and without Çm spin labels, we found that state-of-the-art force fields with explicit parameterization of the spin label were able to describe the conformational ensemble present in our experiments. The MD simulations further confirmed that the Çm spin labels are excellent mimics of cytidine inducing only small local changes in the RNA structure. Çm spin labels are thus ideally suited for high-precision EPR experiments to probe the structure and, in conjunction with MD simulations, motions of RNA.
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Affiliation(s)
- Maximilian Gauger
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue Str. 7, 60438, Frankfurt am Main, Germany
| | - Marcel Heinz
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue Str. 3, 60438, Frankfurt am Main, Germany
| | | | - Lukas S Stelzl
- Faculty of Biology, Johannes Gutenberg University, 55128, Mainz, Germany
- KOMET 1, Institute of Physics, Johannes Gutenberg University, Staudingerweg 9, 55128, Mainz, Germany
- Institute of Quantitative and Computational Bioscience (IQCB), Johannes Gutenberg University Mainz, 55128, Mainz, Germany
- Institute of Molecular Biology (IMB), 55128, Mainz, Germany
| | - Nicole Erlenbach
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue Str. 7, 60438, Frankfurt am Main, Germany
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue Str. 3, 60438, Frankfurt am Main, Germany
- Institute of Biophysics, Goethe University Frankfurt, Max-von-Laue Str. 1, 60438, Frankfurt am Main, Germany
| | | | - Thomas F Prisner
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue Str. 7, 60438, Frankfurt am Main, Germany
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2
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Huang K, Fang X. A review on recent advances in methods for site-directed spin labeling of long RNAs. Int J Biol Macromol 2023; 239:124244. [PMID: 37001783 DOI: 10.1016/j.ijbiomac.2023.124244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 01/12/2023] [Accepted: 03/15/2023] [Indexed: 03/31/2023]
Abstract
RNAs are important biomolecules that play essential roles in various cellular processes and are crucially linked with many human diseases. The key to elucidate the mechanisms underlying their biological functions and develop RNA-based therapeutics is to investigate RNA structure and dynamics and their connections to function in detail using a variety of approaches. Magnetic resonance techniques including paramagnetic nuclear magnetic resonance (NMR) and electron magnetic resonance (EPR) spectroscopies have proved to be powerful tools to gain insights into such properties. The prerequisites for paramagnetic NMR and EPR studies on RNAs are to achieve site-specific spin labeling of the intrinsically diamagnetic RNAs, which however is not trivial, especially for long ones. In this review, we present some covalent labeling strategies that allow site-specific introduction of electron spins to long RNAs. Generally, these strategies include assembly of long RNAs via enzymatic ligation of short oligonucleotides, co- and post-transcriptional site-specific labeling empowered with the unnatural base pair system, and direct enzymatic functionalization of natural RNAs. We introduce a few case studies to discuss the advantages and limitations of each strategy, and to provide a vision for the future development.
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3
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Miao Q, Nitsche C, Orton H, Overhand M, Otting G, Ubbink M. Paramagnetic Chemical Probes for Studying Biological Macromolecules. Chem Rev 2022; 122:9571-9642. [PMID: 35084831 PMCID: PMC9136935 DOI: 10.1021/acs.chemrev.1c00708] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Indexed: 12/11/2022]
Abstract
Paramagnetic chemical probes have been used in electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopy for more than four decades. Recent years witnessed a great increase in the variety of probes for the study of biological macromolecules (proteins, nucleic acids, and oligosaccharides). This Review aims to provide a comprehensive overview of the existing paramagnetic chemical probes, including chemical synthetic approaches, functional properties, and selected applications. Recent developments have seen, in particular, a rapid expansion of the range of lanthanoid probes with anisotropic magnetic susceptibilities for the generation of structural restraints based on residual dipolar couplings and pseudocontact shifts in solution and solid state NMR spectroscopy, mostly for protein studies. Also many new isotropic paramagnetic probes, suitable for NMR measurements of paramagnetic relaxation enhancements, as well as EPR spectroscopic studies (in particular double resonance techniques) have been developed and employed to investigate biological macromolecules. Notwithstanding the large number of reported probes, only few have found broad application and further development of probes for dedicated applications is foreseen.
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Affiliation(s)
- Qing Miao
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
- School
of Chemistry &Chemical Engineering, Shaanxi University of Science & Technology, Xi’an710021, China
| | - Christoph Nitsche
- Research
School of Chemistry, The Australian National
University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
| | - Henry Orton
- Research
School of Chemistry, The Australian National
University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
- ARC
Centre of Excellence for Innovations in Peptide & Protein Science,
Research School of Chemistry, Australian
National University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
| | - Mark Overhand
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
| | - Gottfried Otting
- Research
School of Chemistry, The Australian National
University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
- ARC
Centre of Excellence for Innovations in Peptide & Protein Science,
Research School of Chemistry, Australian
National University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
| | - Marcellus Ubbink
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
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4
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Vicino MF, Wuebben C, Kerzhner M, Famulok M, Schiemann O. Spin Labeling of Long RNAs Via Click Reaction and Enzymatic Ligation. Methods Mol Biol 2022; 2439:205-221. [PMID: 35226324 DOI: 10.1007/978-1-0716-2047-2_14] [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
Electron paramagnetic resonance (EPR) is a spectroscopic method for investigating structures, conformational changes, and dynamics of biomacromolecules, for example, oligonucleotides. In order to be applicable, the oligonucleotide has to be labeled site-specifically with paramagnetic tags, the so-called spin labels. Here, we provide a protocol for spin labeling of long oligonucleotides with nitroxides. In the first step, a short and commercially available RNA strand is labeled with a nitroxide via a copper-(I)-catalyzed azide-alkyne cycloaddition (CuAAC), also referred to as "click" reaction. In the second step, the labeled RNA strand is fused to another RNA sequence by means of enzymatic ligation to obtain the labeled full-length construct. The protocol is robust and has been shown experimentally to deliver high yields for RNA sequences up to 81 nucleotides, but longer strands are in principle also feasible. Moreover, it sets the path to label, for example, long riboswitches, ribozymes, and DNAzymes for coarse-grained structure determination and enables to investigate mechanistical features of these systems.
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Affiliation(s)
- Maria Francesca Vicino
- Institute of Physical and Theoretical Chemistry, Rheinische Friedrich Wilhelms University, Bonn, Germany
| | - Christine Wuebben
- Institute of Physical and Theoretical Chemistry, Rheinische Friedrich Wilhelms University, Bonn, Germany
| | - Mark Kerzhner
- Life & Medical Sciences Institute (LIMES), Chemische Biologie, c/o Kekulé-Institut für organische Chemie, Bonn, Germany
| | - Michael Famulok
- Life & Medical Sciences Institute (LIMES), Chemische Biologie, c/o Kekulé-Institut für organische Chemie, Bonn, Germany
| | - Olav Schiemann
- Institute of Physical and Theoretical Chemistry, Rheinische Friedrich Wilhelms University, Bonn, Germany.
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5
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Qureshi NS, Matzel T, Cetiner EC, Schnieders R, Jonker HRA, Schwalbe H, Fürtig B. NMR structure of the Vibrio vulnificus ribosomal protein S1 domains D3 and D4 provides insights into molecular recognition of single-stranded RNAs. Nucleic Acids Res 2021; 49:7753-7764. [PMID: 34223902 PMCID: PMC8287937 DOI: 10.1093/nar/gkab562] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 06/09/2021] [Accepted: 06/14/2021] [Indexed: 01/14/2023] Open
Abstract
The ribosomal S1 protein (rS1) is indispensable for translation initiation in Gram-negative bacteria. rS1 is a multidomain protein that acts as an RNA chaperone and ensures that mRNAs can bind the ribosome in a single-stranded conformation, which could be related to fast recognition. Although many ribosome structures were solved in recent years, a high-resolution structure of a two-domain mRNA-binding competent rS1 construct is not yet available. Here, we present the NMR solution structure of the minimal mRNA-binding fragment of Vibrio Vulnificus rS1 containing the domains D3 and D4. Both domains are homologues and adapt an oligonucleotide-binding fold (OB fold) motif. NMR titration experiments reveal that recognition of miscellaneous mRNAs occurs via a continuous interaction surface to one side of these structurally linked domains. Using a novel paramagnetic relaxation enhancement (PRE) approach and exploring different spin-labeling positions within RNA, we were able to track the location and determine the orientation of the RNA in the rS1-D34 bound form. Our investigations show that paramagnetically labeled RNAs, spiked into unmodified RNA, can be used as a molecular ruler to provide structural information on protein-RNA complexes. The dynamic interaction occurs on a defined binding groove spanning both domains with identical β2-β3-β5 interfaces. Evidently, the 3'-ends of the cis-acting RNAs are positioned in the direction of the N-terminus of the rS1 protein, thus towards the 30S binding site and adopt a conformation required for translation initiation.
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Affiliation(s)
- Nusrat Shahin Qureshi
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, Frankfurt am Main, Hesse 60438, Germany
| | - Tobias Matzel
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, Frankfurt am Main, Hesse 60438, Germany
| | - Erhan Can Cetiner
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, Frankfurt am Main, Hesse 60438, Germany
| | - Robbin Schnieders
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, Frankfurt am Main, Hesse 60438, Germany
| | - Hendrik R A Jonker
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, Frankfurt am Main, Hesse 60438, Germany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, Frankfurt am Main, Hesse 60438, Germany
| | - Boris Fürtig
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, Frankfurt am Main, Hesse 60438, Germany
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6
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Wuebben C, Vicino MF, Mueller M, Schiemann O. Do the P1 and P2 hairpins of the Guanidine-II riboswitch interact? Nucleic Acids Res 2020; 48:10518-10526. [PMID: 32857846 PMCID: PMC7544219 DOI: 10.1093/nar/gkaa703] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 08/08/2020] [Accepted: 08/12/2020] [Indexed: 01/09/2023] Open
Abstract
Riboswitches regulate genes by adopting different structures in responds to metabolite binding. The guanidine-II riboswitch is the smallest representative of the ykkC class with the mechanism of its function being centred on the idea that its two stem loops P1 and P2 form a kissing hairpin interaction upon binding of guanidinium (Gdm+). This mechanism is based on in-line probing experiments with the full-length riboswitch and crystal structures of the truncated stem loops P1 and P2. However, the crystal structures reveal only the formation of the homodimers P1 | P1 and P2 | P2 but not of the proposed heterodimer P1 | P2. Here, site-directed spin labeling (SDSL) in combination with Pulsed Electron–Electron Double Resonance (PELDOR or DEER) is used to study their structures in solution and how they change upon binding of Gdm+. It is found that both hairpins adopt different structures in solution and that binding of Gdm+ does indeed lead to the formation of the heterodimer but alongside the homodimers in a statistical 1:2:1 fashion. These results do thus support the proposed switching mechanism.
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Affiliation(s)
- Christine Wuebben
- Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstr. 12, 53115 Bonn, Germany
| | - Maria F Vicino
- Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstr. 12, 53115 Bonn, Germany
| | - Marcel Mueller
- Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstr. 12, 53115 Bonn, Germany
| | - Olav Schiemann
- Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstr. 12, 53115 Bonn, Germany
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7
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Cetiner EC, Jonker HRA, Helmling C, Gophane DB, Grünewald C, Sigurdsson ST, Schwalbe H. Paramagnetic-iterative relaxation matrix approach: extracting PRE-restraints from NOESY spectra for 3D structure elucidation of biomolecules. JOURNAL OF BIOMOLECULAR NMR 2019; 73:699-712. [PMID: 31606877 DOI: 10.1007/s10858-019-00282-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 09/27/2019] [Indexed: 06/10/2023]
Abstract
Paramagnetic relaxation enhancement (PRE) can be used to determine long-range distance restraints in biomolecules. The PREs are typically determined by analysis of intensity differences in HSQC experiments of paramagnetic and diamagnetic spin labels. However, this approach requires both isotope- and spin-labelling. Herein, we report a novel method to evaluate NOESY intensities in the presence of a paramagnetic moiety to determine PRE restraints. The advantage of our approach over HSQC-based approaches is the increased number of available signals without the need for isotope labelling. NOESY intensities affected by a paramagnetic center were evaluated during a structure calculation within the paramagnetic iterative relaxation matrix approach (P-IRMA). We applied P-IRMA to a 14-mer RNA with a known NMR solution structure, which allowed us to assess the quality of the PRE restraints. To this end, three different spin labels have been attached at different positions of the 14-mer to test the influence of flexibility on the structure calculation. Structural disturbances introduced by the spin label have been evaluated by chemical shift analysis. Furthermore, the impact of P-IRMA on the quality of the structure bundles were tested by intentionally leaving out available diamagnetic restraints. Our analyses show that P-IRMA is a powerful tool to refine RNA structures for systems that are insufficiently described by using only diamagnetic restraints.
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Affiliation(s)
- E C Cetiner
- Institut für Organische Chemie und Chemische Biologie, Zentrum für Biomolekulare Magnetische Resonanz, Goethe Universität Frankfurt am Main, Max-von-Laue Straße 7, 60438, Frankfurt am Main, Germany
| | - H R A Jonker
- Institut für Organische Chemie und Chemische Biologie, Zentrum für Biomolekulare Magnetische Resonanz, Goethe Universität Frankfurt am Main, Max-von-Laue Straße 7, 60438, Frankfurt am Main, Germany
| | - C Helmling
- Institut für Organische Chemie und Chemische Biologie, Zentrum für Biomolekulare Magnetische Resonanz, Goethe Universität Frankfurt am Main, Max-von-Laue Straße 7, 60438, Frankfurt am Main, Germany
| | - D B Gophane
- Department of Chemistry Science Institute, University of Iceland, Dunhaga 3, 107, Reykjavik, Iceland
| | - C Grünewald
- Institut für Organische Chemie und Chemische Biologie, Zentrum für Biomolekulare Magnetische Resonanz, Goethe Universität Frankfurt am Main, Max-von-Laue Straße 7, 60438, Frankfurt am Main, Germany
| | - S Th Sigurdsson
- Department of Chemistry Science Institute, University of Iceland, Dunhaga 3, 107, Reykjavik, Iceland
| | - H Schwalbe
- Institut für Organische Chemie und Chemische Biologie, Zentrum für Biomolekulare Magnetische Resonanz, Goethe Universität Frankfurt am Main, Max-von-Laue Straße 7, 60438, Frankfurt am Main, Germany.
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8
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Refining RNA solution structures with the integrative use of label-free paramagnetic relaxation enhancement NMR. BIOPHYSICS REPORTS 2019. [DOI: 10.1007/s41048-019-00099-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
AbstractNMR structure calculation is inherently integrative, and can incorporate new experimental data as restraints. As RNAs have lower proton densities and are more conformational heterogenous than proteins, the refinement of RNA structures can benefit from additional types of restraints. Paramagnetic relaxation enhancement (PRE) provides distance information between a paramagnetic probe and protein or RNA nuclei. However, covalent conjugation of a paramagnetic probe is difficult for RNAs, thus limiting the use of PRE NMR for RNA structure characterization. Here, we show that the solvent PRE can be accurately measured for RNA labile imino protons, simply with the addition of an inert paramagnetic cosolute. Demonstrated on three RNAs that have increasingly complex topologies, we show that the incorporation of the solvent PRE restraints can significantly improve the precision and accuracy of RNA structures. Importantly, the solvent PRE data can be collected for RNAs without isotope enrichment. Thus, the solvent PRE method can work integratively with other biophysical techniques for better characterization of RNA structures.
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9
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Gophane DB, Endeward B, Prisner TF, Sigurdsson ST. A semi-rigid isoindoline-derived nitroxide spin label for RNA. Org Biomol Chem 2019; 16:816-824. [PMID: 29326999 DOI: 10.1039/c7ob02870a] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A new isoindoline-derived benzimidazole nitroxide spin label, ImUm, was synthesized and incorporated into RNA oligoribonucleotides. ImUm is the first example of a conformationally unambiguous spin label for RNA, in which the nitroxide N-O bond lies on the same axis as the single bond used to attach the rigid isoindoline-based spin label to a uridine base. This results in minimal displacement of the nitroxide upon rotation of this single bond, which is a useful property for a label to be used for distance measurements. Continuous-wave (CW) EPR measurements of RNA duplexes containing ImUm indicate a restricted rotation around this single bond, presumably due to an intramolecular hydrogen bond between the benzimidazole N-H and O4 of the uracil. Orientation-selective pulsed electron-electron double resonance (PELDOR, also called double electron-electron resonance, or DEER) distance measurements between two spin labels in two RNA duplexes showed in one case a strong orientation dependence, further confirming the restricted motion of the spin labels in RNA duplexes.
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Affiliation(s)
- Dnyaneshwar B Gophane
- University of Iceland, Department of Chemistry, Science Institute, Dunhaga 3, 107 Reykjavik, Iceland.
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10
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Hatano A, Terado N, Kanno Y, Nakamura T, Kawai G. Synthesis of a protected ribonucleoside phosphoramidite-linked spin label via an alkynyl chain at the 5′ position of uridine. SYNTHETIC COMMUN 2019. [DOI: 10.1080/00397911.2018.1545033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Akihiko Hatano
- Department of Chemistry, Faculty of Engineering , Shibaura Institute of Technology , Saitama , Japan
| | - Nanae Terado
- Department of Chemistry, Faculty of Engineering , Shibaura Institute of Technology , Saitama , Japan
| | - Yuichi Kanno
- Department of Chemistry, Faculty of Engineering , Shibaura Institute of Technology , Saitama , Japan
| | - Toshikazu Nakamura
- Department of Materials Molecular Science, Institute for Molecular Science , Okazaki , Japan
| | - Gota Kawai
- Department of Life and Environmental Sciences, Faculty of Engineering, Chiba Institute of Technology , Chiba , Japan
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11
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Kuzhelev AA, Krumkacheva OA, Shevelev GY, Yulikov M, Fedin MV, Bagryanskaya EG. Room-temperature distance measurements using RIDME and the orthogonal spin labels trityl/nitroxide. Phys Chem Chem Phys 2018; 20:10224-10230. [PMID: 29594278 DOI: 10.1039/c8cp01093e] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron paramagnetic resonance (EPR) based nanometer distance measurements at ambient temperatures are of particular interest for structural biology applications. The nitroxide spin labels commonly used in EPR reveal relatively short transverse relaxation under these conditions, which limits their use for detecting static dipolar interactions. At the same time, the longitudinal relaxation of nitroxide spin labels is still long enough to allow using them as 'pumped' species in the relaxation induced dipolar modulation enhancement (RIDME) experiment where the detection is carried out on the slower relaxing triarylmethyl (TAM) spin labels. In the present study, we report the first demonstration of room-temperature RIDME distance measurements in nucleic acids using TAM as the slow-relaxing detected species and traditional nitroxide as the fast-relaxing partner spin. Two types of immobilizers, glassy trehalose and the modified silica gel Nucleosil, were used for immobilization of the spin-labeled biomolecules. The room-temperature RIDME-based distance distributions are in good agreement with those measured at 80 K by other techniques. Room-temperature RIDME on the spin pairs trityl/nitroxide may become a useful method for the structural characterization of biomacromolecules and biomolecular complexes at near physiological temperatures.
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Affiliation(s)
- Andrey A Kuzhelev
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Novosibirsk 630090, Russia.
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12
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Weinrich T, Jaumann EA, Scheffer U, Prisner TF, Göbel MW. A Cytidine Phosphoramidite with Protected Nitroxide Spin Label: Synthesis of a Full-Length TAR RNA and Investigation by In-Line Probing and EPR Spectroscopy. Chemistry 2018; 24:6202-6207. [PMID: 29485736 DOI: 10.1002/chem.201800167] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 02/23/2018] [Indexed: 01/20/2023]
Abstract
EPR studies on RNA are complicated by three major obstacles related to the chemical nature of nitroxide spin labels: Decomposition while oligonucleotides are chemically synthesized, further decay during enzymatic strand ligation, and undetected changes in conformational equilibria due to the steric demand of the label. Herein possible solutions for all three problems are presented: A 2-nitrobenzyloxymethyl protective group for nitroxides that is stable under all conditions of chemical RNA synthesis and can be removed photochemically. By careful selection of ligation sites and splint oligonucleotides, high yields were achieved in the assembly of a full-length HIV-1 TAR RNA labeled with two protected nitroxide groups. PELDOR measurements on spin-labeled TAR in the absence and presence of arginine amide indicated arrest of interhelical motions on ligand binding. Finally, even minor changes in conformation due to the presence of spin labels are detected with high sensitivity by in-line probing.
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Affiliation(s)
- Timo Weinrich
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt am Main, Germany
| | - Eva A Jaumann
- Institute for Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt am Main, Germany
| | - Ute Scheffer
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt am Main, Germany
| | - Thomas F Prisner
- Institute for Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt am Main, Germany
| | - Michael W Göbel
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt am Main, Germany
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13
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Kamble NR, Sigurdsson ST. Purine-Derived Nitroxides for Noncovalent Spin-Labeling of Abasic Sites in Duplex Nucleic Acids. Chemistry 2018; 24:4157-4164. [DOI: 10.1002/chem.201705410] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Indexed: 12/27/2022]
Affiliation(s)
- Nilesh R. Kamble
- 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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Schnorr KA, Gophane DB, Helmling C, Cetiner E, Pasemann K, Fürtig B, Wacker A, Qureshi NS, Gränz M, Barthelmes D, Jonker HRA, Stirnal E, Sigurdsson ST, Schwalbe H. Impact of spin label rigidity on extent and accuracy of distance information from PRE data. JOURNAL OF BIOMOLECULAR NMR 2017; 68:53-63. [PMID: 28500543 DOI: 10.1007/s10858-017-0114-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/03/2017] [Indexed: 06/07/2023]
Abstract
Paramagnetic relaxation enhancement (PRE) is a versatile tool for NMR spectroscopic structural and kinetic studies in biological macromolecules. Here, we compare the quality of PRE data derived from two spin labels with markedly different dynamic properties for large RNAs using the I-A riboswitch aptamer domain (78 nt) from Mesoplamsa florum as model system. We designed two I-A aptamer constructs that were spin-labeled by noncovalent hybridization of short spin-labeled oligomer fragments. As an example of a flexible spin label, UreidoU-TEMPO was incorporated into the 3' terminal end of helix P1 while, the recently developed rigid spin-label Çm was incorporated in the 5' terminal end of helix P1. We determined PRE rates obtained from aromatic 13C bound proton intensities and compared these rates to PREs derived from imino proton intensities in this sizeable RNA (~78 nt). PRE restraints derived from both imino and aromatic protons yielded similar data quality, and hence can both be reliably used for PRE determination. For NMR, the data quality derived from the rigid spin label Çm is slightly better than the data quality for the flexible UreidoTEMPO as judged by comparison of the structural agreement with the I-A aptamer crystal structure (3SKI).
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Affiliation(s)
- K A Schnorr
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-Universität, Max-von-Laue Strasse 7, 60438, Frankfurt am Main, Germany
| | - D B Gophane
- Department of Chemistry, Science Institute, University of Iceland, Dunhaga 3, 107, Reykjavik, Iceland
| | - C Helmling
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-Universität, Max-von-Laue Strasse 7, 60438, Frankfurt am Main, Germany
| | - E Cetiner
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-Universität, Max-von-Laue Strasse 7, 60438, Frankfurt am Main, Germany
| | - K Pasemann
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-Universität, Max-von-Laue Strasse 7, 60438, Frankfurt am Main, Germany
| | - B Fürtig
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-Universität, Max-von-Laue Strasse 7, 60438, Frankfurt am Main, Germany
| | - A Wacker
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-Universität, Max-von-Laue Strasse 7, 60438, Frankfurt am Main, Germany
| | - N S Qureshi
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-Universität, Max-von-Laue Strasse 7, 60438, Frankfurt am Main, Germany
| | - M Gränz
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Physical and Theoretical Chemistry, Johann Wolfgang Goethe-Universität, Max-von-Laue Strasse 7, 60438, Frankfurt am Main, Germany
| | - D Barthelmes
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-Universität, Max-von-Laue Strasse 7, 60438, Frankfurt am Main, Germany
| | - H R A Jonker
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-Universität, Max-von-Laue Strasse 7, 60438, Frankfurt am Main, Germany
| | - E Stirnal
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-Universität, Max-von-Laue Strasse 7, 60438, Frankfurt am Main, Germany
| | - S Th Sigurdsson
- Department of Chemistry, Science Institute, University of Iceland, Dunhaga 3, 107, Reykjavik, Iceland
| | - H Schwalbe
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-Universität, Max-von-Laue Strasse 7, 60438, Frankfurt am Main, Germany.
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15
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Weinrich T, Gränz M, Grünewald C, Prisner TF, Göbel MW. Synthesis of a Cytidine Phosphoramidite with Protected Nitroxide Spin Label for EPR Experiments with RNA. European J Org Chem 2016. [DOI: 10.1002/ejoc.201601174] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Timo Weinrich
- Institute of Organic Chemistry and Chemical Biology; Goethe-University Frankfurt; Max-von-Laue-Str. 7 60438 Frankfurt am Main Germany
| | - Markus Gränz
- Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance; Goethe-University Frankfurt; Max-von-Laue-Str. 7 60438 Frankfurt am Main Germany
| | - Christian Grünewald
- Institute of Organic Chemistry and Chemical Biology; Goethe-University Frankfurt; Max-von-Laue-Str. 7 60438 Frankfurt am Main Germany
| | - Thomas F. Prisner
- Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance; Goethe-University Frankfurt; Max-von-Laue-Str. 7 60438 Frankfurt am Main Germany
| | - Michael W. Göbel
- Institute of Organic Chemistry and Chemical Biology; Goethe-University Frankfurt; Max-von-Laue-Str. 7 60438 Frankfurt am Main Germany
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16
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Esquiaqui JM, Sherman EM, Ye JD, Fanucci GE. Conformational Flexibility and Dynamics of the Internal Loop and Helical Regions of the Kink–Turn Motif in the Glycine Riboswitch by Site-Directed Spin-Labeling. Biochemistry 2016; 55:4295-305. [DOI: 10.1021/acs.biochem.6b00287] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jackie M. Esquiaqui
- Department
of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Eileen M. Sherman
- Department
of Chemistry, University of Central Florida, 4000 Central Florida Boulevard, Orlando, Florida 32816, United States
| | - Jing-Dong Ye
- Department
of Chemistry, University of Central Florida, 4000 Central Florida Boulevard, Orlando, Florida 32816, United States
| | - Gail E. Fanucci
- Department
of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
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17
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Kerzhner M, Abdullin D, Więcek J, Matsuoka H, Hagelueken G, Schiemann O, Famulok M. Post-synthetic Spin-Labeling of RNA through Click Chemistry for PELDOR Measurements. Chemistry 2016; 22:12113-21. [PMID: 27412453 DOI: 10.1002/chem.201601897] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Indexed: 01/24/2023]
Abstract
Site-directed spin labeling of RNA based on click chemistry is used in combination with pulsed electron-electron double resonance (PELDOR) to benchmark a nitroxide spin label, called here dŲ. We compare this approach with another established method that employs the rigid spin label Çm for RNA labeling. By using CD spectroscopy, thermal denaturation measurements, CW-EPR as well as PELDOR we analyzed and compared the influence of dŲ and Çm on a self-complementary RNA duplex. Our results demonstrate that the conformational diversity of dŲ is significantly reduced near the freezing temperature of a phosphate buffer, resulting in strongly orientation-selective PELDOR time traces of the dŲ-labeled RNA duplex.
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Affiliation(s)
- Mark Kerzhner
- Life & Medical Sciences Institute, Chemical Biology & Medicinal Chemistry Unit c/o Kekulé-Institut für Organische Chemie und Biochemie, University of Bonn, Gerhard-Domagk-Str. 1, 53121, Bonn, Germany
| | - Dinar Abdullin
- Institute for Physical and Theoretical Chemistry, University of Bonn, Wegelerstr. 12, 53115, Bonn, Germany
| | - Jennifer Więcek
- Institute for Physical and Theoretical Chemistry, University of Bonn, Wegelerstr. 12, 53115, Bonn, Germany
| | - Hideto Matsuoka
- Institute for Physical and Theoretical Chemistry, University of Bonn, Wegelerstr. 12, 53115, 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.
| | - Michael Famulok
- Life & Medical Sciences Institute, Chemical Biology & Medicinal Chemistry Unit c/o Kekulé-Institut für Organische Chemie und Biochemie, University of Bonn, Gerhard-Domagk-Str. 1, 53121, Bonn, Germany. .,Max-Planck Fellow Group Chemical Biology, Center of Advanced European Studies and Research, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany.
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18
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Halbmair K, Seikowski J, Tkach I, Höbartner C, Sezer D, Bennati M. High-resolution measurement of long-range distances in RNA: pulse EPR spectroscopy with TEMPO-labeled nucleotides. Chem Sci 2016; 7:3172-3180. [PMID: 29997809 PMCID: PMC6005265 DOI: 10.1039/c5sc04631a] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 02/01/2016] [Indexed: 01/02/2023] Open
Abstract
Distance measurements in RNAs by pulse EPR with TEMPO-labeled nucleotides allow for model free conversion of distances into base-pair separation.
Structural information at atomic resolution of biomolecular assemblies, such as RNA and RNA protein complexes, is fundamental to comprehend biological function. Modern spectroscopic methods offer exceptional opportunities in this direction. Here we present the capability of pulse EPR to report high-resolution long-range distances in RNAs by means of a recently developed spin labeled nucleotide, which carries the TEMPO group directly attached to the nucleobase and preserves Watson–Crick base-pairing. In a representative RNA duplex with spin-label separations up to 28 base pairs (≈8 nm) we demonstrate that the label allows for a model-free conversion of inter-spin distances into base-pair separation (Δbp) if broad-band pulse excitation at Q band frequencies (34 GHz) is applied. The observed distance distribution increases from ±0.2 nm for Δbp = 10 to only ±0.5 nm for Δbp = 28, consistent with only small deviations from the “ideal” A-form RNA structure. Molecular dynamics (MD) simulations conducted at 20 °C show restricted conformational freedom of the label. MD-generated structural deviations from an “ideal” A-RNA geometry help disentangle the contributions of local flexibility of the label and its neighboring nucleobases and global deformations of the RNA double helix to the experimental distance distributions. The study demonstrates that our simple but strategic spin labeling procedure can access detailed structural information on RNAs at atomic resolution over distances that match the size of macromolecular RNA complexes.
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Affiliation(s)
- Karin Halbmair
- Max Planck Institute for Biophysical Chemistry , 37077 Göttingen , Germany .
| | - Jan Seikowski
- Max Planck Institute for Biophysical Chemistry , 37077 Göttingen , Germany .
| | - Igor Tkach
- Max Planck Institute for Biophysical Chemistry , 37077 Göttingen , Germany .
| | - Claudia Höbartner
- Max Planck Institute for Biophysical Chemistry , 37077 Göttingen , Germany . .,Department of Organic and Biomolecular Chemistry , University of Göttingen , 37077 Göttingen , Germany
| | - Deniz Sezer
- Faculty of Engineering and Natural Sciences , Sabanci University , 34956 Istanbul , Turkey .
| | - Marina Bennati
- Max Planck Institute for Biophysical Chemistry , 37077 Göttingen , Germany . .,Department of Organic and Biomolecular Chemistry , University of Göttingen , 37077 Göttingen , Germany
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19
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20
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Saha S, Jagtap AP, Sigurdsson ST. Site-Directed Spin Labeling of RNA by Postsynthetic Modification of 2'-Amino Groups. Methods Enzymol 2015; 563:397-414. [PMID: 26478493 DOI: 10.1016/bs.mie.2015.07.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
To elucidate mechanisms that govern functions of nucleic acids, it is essential to understand their structure and dynamics. Electron paramagnetic resonance (EPR) spectroscopy is a valuable technique that is routinely used to study those aspects of nucleic acids. A prerequisite for most EPR studies of nucleic acids is incorporation of spin labels at specific sites, known as site-directed spin labeling (SDSL). There are two main strategies for SDSL through formation of covalent bonds, i.e., the phosphoramidite approach and postsynthetic spin-labeling. After describing briefly the advantages and disadvantages of these two strategies, postsynthetic labeling of 2'-amino groups in RNA is delineated. Postsynthetic labeling of 2'-amino groups in RNA using 4-isocyanato-TEMPO has long been established as a useful approach. However, this method has some drawbacks, both with regard to the spin-labeling protocol and the flexibility of the spin label itself. Recently reported isothiocyanate-substituted aromatic isoindoline-derived nitroxides can be used to quantitatively and selectively modify 2'-amino groups in RNA and do not have the drawbacks associated with 4-isocyanato-TEMPO. This chapter provides a detailed description of the postsynthetic spin-labeling methods of 2'-amino groups in RNA with a special focus on using the aromatic isothiocyanate spin labels.
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Affiliation(s)
- Subham Saha
- Department of Chemistry, Science Institute, University of Iceland, Reykjavik, Iceland
| | - Anil P Jagtap
- Department of Chemistry, Science Institute, University of Iceland, Reykjavik, Iceland
| | - Snorri Th Sigurdsson
- Department of Chemistry, Science Institute, University of Iceland, Reykjavik, Iceland.
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21
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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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22
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Saha S, Jagtap AP, Sigurdsson ST. Site-directed spin labeling of 2′-amino groups in RNA with isoindoline nitroxides that are resistant to reduction. Chem Commun (Camb) 2015; 51:13142-5. [DOI: 10.1039/c5cc05014f] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
2'-Amino groups in RNA were selectively spin labeled with reductively stable isoindoline nitroxides through a high-yielding reaction with aromatic isothiocyanates.
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Affiliation(s)
- Subham Saha
- University of Iceland
- Department of Chemistry
- Science Institute
- 107 Reykjavik
- Iceland
| | - Anil P. Jagtap
- University of Iceland
- Department of Chemistry
- Science Institute
- 107 Reykjavik
- Iceland
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23
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New developments in spin labels for pulsed dipolar EPR. Molecules 2014; 19:16998-7025. [PMID: 25342554 PMCID: PMC6271499 DOI: 10.3390/molecules191016998] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/07/2014] [Accepted: 10/13/2014] [Indexed: 11/17/2022] Open
Abstract
Spin labelling is a chemical technique that enables the integration of a molecule containing an unpaired electron into another framework for study. Given the need to understand the structure, dynamics, and conformational changes of biomacromolecules, spin labelling provides a relatively non-intrusive technique and has certain advantages over X-ray crystallography; which requires high quality crystals. The technique relies on the design of binding probes that target a functional group, for example, the thiol group of a cysteine residue within a protein. The unpaired electron is typically supplied through a nitroxide radical and sterically shielded to preserve stability. Pulsed electron paramagnetic resonance (EPR) techniques allow small magnetic couplings to be measured (e.g., <50 MHz) providing information on single label probes or the dipolar coupling between multiple labels. In particular, distances between spin labels pairs can be derived which has led to many protein/enzymes and nucleotides being studied. Here, we summarise recent examples of spin labels used for pulse EPR that serve to illustrate the contribution of chemistry to advancing discoveries in this field.
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24
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Göbl C, Madl T, Simon B, Sattler M. NMR approaches for structural analysis of multidomain proteins and complexes in solution. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2014; 80:26-63. [PMID: 24924266 DOI: 10.1016/j.pnmrs.2014.05.003] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 05/14/2014] [Indexed: 05/22/2023]
Abstract
NMR spectroscopy is a key method for studying the structure and dynamics of (large) multidomain proteins and complexes in solution. It plays a unique role in integrated structural biology approaches as especially information about conformational dynamics can be readily obtained at residue resolution. Here, we review NMR techniques for such studies focusing on state-of-the-art tools and practical aspects. An efficient approach for determining the quaternary structure of multidomain complexes starts from the structures of individual domains or subunits. The arrangement of the domains/subunits within the complex is then defined based on NMR measurements that provide information about the domain interfaces combined with (long-range) distance and orientational restraints. Aspects discussed include sample preparation, specific isotope labeling and spin labeling; determination of binding interfaces and domain/subunit arrangements from chemical shift perturbations (CSP), nuclear Overhauser effects (NOEs), isotope editing/filtering, cross-saturation, and differential line broadening; and based on paramagnetic relaxation enhancements (PRE) using covalent and soluble spin labels. Finally, the utility of complementary methods such as small-angle X-ray or neutron scattering (SAXS, SANS), electron paramagnetic resonance (EPR) or fluorescence spectroscopy techniques is discussed. The applications of NMR techniques are illustrated with studies of challenging (high molecular weight) protein complexes.
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Affiliation(s)
- Christoph Göbl
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technische Universität München, Garching, Germany
| | - Tobias Madl
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technische Universität München, Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany; Institute of Molecular Biology, University of Graz, Graz, Austria.
| | - Bernd Simon
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Michael Sattler
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technische Universität München, Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany.
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25
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Lebars I, Vileno B, Bourbigot S, Turek P, Wolff P, Kieffer B. A fully enzymatic method for site-directed spin labeling of long RNA. Nucleic Acids Res 2014; 42:e117. [PMID: 24981512 PMCID: PMC4150755 DOI: 10.1093/nar/gku553] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Site-directed spin labeling is emerging as an essential tool to investigate the structural and dynamical features of RNA. We propose here an enzymatic method, which allows the insertion of a paramagnetic center at a specific position in an RNA molecule. The technique is based on a segmental approach using a ligation protocol with T4 RNA ligase 2. One transcribed acceptor RNA is ligated to a donor RNA in which a thio-modified nucleotide is introduced at its 5′-end by in vitro transcription with T7 RNA polymerase. The paramagnetic thiol-specific reagent is subsequently attached to the RNA ligation product. This novel strategy is demonstrated by introducing a paramagnetic probe into the 55 nucleotides long RNA corresponding to K-turn and Specifier Loop domains from the Bacillus subtilis tyrS T-Box leader RNA. The efficiency of the coupling reaction and the quality of the resulting spin-labeled RNA were assessed by Mass Spectrometry, Electron Paramagnetic Resonance (EPR) and Nuclear Magnetic Resonance (NMR). This method enables various combinations of isotopic segmental labeling and spin labeling schemes, a strategy that will be of particular interest to investigate the structural and dynamical properties of large RNA complexes by NMR and EPR spectroscopies.
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Affiliation(s)
- Isabelle Lebars
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Département de Biologie Structurale, Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institut National de la Santé et de la Recherche Médicale (INSERM) U964/Université de Strasbourg, 1 rue Laurent Fries, BP 10142, 67404 Illkirch cedex, France
| | - Bertrand Vileno
- Institut de Chimie, Laboratoire Propriétés Optiques & Magnétiques des Architectures Moléculaires, Université de Strasbourg, UMR 7177 CNRS, 4 rue Blaise Pascal, CS 90032, 67081 Strasbourg Cedex, France
| | - Sarah Bourbigot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Département de Biologie Structurale, Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institut National de la Santé et de la Recherche Médicale (INSERM) U964/Université de Strasbourg, 1 rue Laurent Fries, BP 10142, 67404 Illkirch cedex, France
| | - Philippe Turek
- Institut de Chimie, Laboratoire Propriétés Optiques & Magnétiques des Architectures Moléculaires, Université de Strasbourg, UMR 7177 CNRS, 4 rue Blaise Pascal, CS 90032, 67081 Strasbourg Cedex, France
| | - Philippe Wolff
- Institut de Biologie Moléculaire et Cellulaire, Plateforme Protéomique Strasbourg Esplanade, FRC 1589 CNRS, 15 rue René Descartes, 67084 Strasbourg Cedex, France Institut de Biologie Moléculaire et Cellulaire, Architecture et Réactivité des ARN, Université de Strasbourg, UPR 9002 CNRS, 15 rue René Descartes, 67084 Strasbourg Cedex, France
| | - Bruno Kieffer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Département de Biologie Structurale, Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institut National de la Santé et de la Recherche Médicale (INSERM) U964/Université de Strasbourg, 1 rue Laurent Fries, BP 10142, 67404 Illkirch cedex, France
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26
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Helmling C, Bessi I, Wacker A, Schnorr KA, Jonker HRA, Richter C, Wagner D, Kreibich M, Schwalbe H. Noncovalent spin labeling of riboswitch RNAs to obtain long-range structural NMR restraints. ACS Chem Biol 2014; 9:1330-9. [PMID: 24673892 DOI: 10.1021/cb500050t] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Paramagnetic relaxation enhancement (PRE) NMR is a powerful method to study structure, dynamics and function of proteins. Up to now, the application of PRE NMR on RNAs is a significant challenge due to the limited size of chemically synthesized RNA. Here, we present a noncovalent spin labeling strategy to spin label RNAs in high yields required for NMR studies. The approach requires the presence of a helix segment composed of about 10 nucleotides (nt) but is not restricted by the size of the RNA. We show successful application of this strategy on the 2'dG sensing aptamer domain of Mesoplasma florum (78 nt). The aptamer domain was prepared in two fragments. A larger fragment was obtained by biochemical means, while a short spin labeled fragment was prepared by chemical solid-phase synthesis. The two fragments were annealed noncovalently by hybridization. We performed NMR, cw-EPR experiments and gel shift assays to investigate the stability of the two-fragment complex. NMR analysis in (15)N-TROSY and (1)H,(1)H-NOESY spectra of both unmodified and spin labeled aptamer domain show that the fragmented system forms a stable hybridization product, is in structural agreement with the full length aptamer domain and maintains its function. Together with structure modeling, experimentally determined (1)H-Γ2 rates are in agreement with reported crystal structure data and show that distance restraints up to 25 Å can be obtained from NMR PRE data of RNA.
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Affiliation(s)
- Christina Helmling
- Institute of Organic Chemistry
and Chemical Biology, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt, Germany
| | - Irene Bessi
- Institute of Organic Chemistry
and Chemical Biology, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt, Germany
| | - Anna Wacker
- Institute of Organic Chemistry
and Chemical Biology, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt, Germany
| | - Kai A. Schnorr
- Institute of Organic Chemistry
and Chemical Biology, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt, Germany
| | - Hendrik R. A. Jonker
- Institute of Organic Chemistry
and Chemical Biology, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt, Germany
| | - Christian Richter
- Institute of Organic Chemistry
and Chemical Biology, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt, Germany
| | - Dominic Wagner
- Institute of Organic Chemistry
and Chemical Biology, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt, Germany
| | - Michael Kreibich
- Institute of Organic Chemistry
and Chemical Biology, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt, Germany
| | - Harald Schwalbe
- Institute of Organic Chemistry
and Chemical Biology, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt, Germany
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27
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Deoxyribozyme-Mediated Ligation for Incorporating EPR Spin Labels and Reporter Groups into RNA. Methods Enzymol 2014; 549:85-104. [DOI: 10.1016/b978-0-12-801122-5.00004-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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28
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Esquiaqui JM, Sherman EM, Ye JD, Fanucci GE. Site-directed spin-labeling strategies and electron paramagnetic resonance spectroscopy for large riboswitches. Methods Enzymol 2014; 549:287-311. [PMID: 25432754 DOI: 10.1016/b978-0-12-801122-5.00013-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Genetic regulation effected by RNA riboswitches is governed by ligand-induced structural reorganization with modulation of RNA conformation and dynamics. Characterization of the conformational states of riboswitches in the presence or absence of salts and ligands is important for understanding how interconversion of riboswitch RNA folding states influences function. The methodology of site-directed spin labeling (SDSL) coupled with electron paramagnetic resonance (EPR) spectroscopy is suitable for such studies, wherein site-specific incorporation of a nitroxide radical spin probe allows for local dynamics and conformational changes to be investigated. This chapter reviews a strategy for SDSL-EPR studies of large riboswitches and uses the full length 232 nucleotide (nt) kink-turn motif-containing Vibrio cholerae (VC) glycine riboswitch as an example. Spin-labeling strategies and the challenges of incorporating spin labels into large riboswitches are reviewed and the approach to overcome these challenges is described. Results are subsequently presented illustrating changes in dynamics within the labeled region of the VC glycine riboswitch as observed using SDSL-EPR.
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Affiliation(s)
- Jackie M Esquiaqui
- Department of Chemistry, University of Florida, Gainesville, Florida, USA
| | - Eileen M Sherman
- Department of Chemistry, University of Central Florida, Orlando, Florida, USA
| | - Jing-Dong Ye
- Department of Chemistry, University of Central Florida, Orlando, Florida, USA.
| | - Gail E Fanucci
- Department of Chemistry, University of Florida, Gainesville, Florida, USA.
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Wunderlich C, Huber RG, Spitzer R, Liedl KR, Kloiber K, Kreutz C. A novel paramagnetic relaxation enhancement tag for nucleic acids: a tool to study structure and dynamics of RNA. ACS Chem Biol 2013; 8:2697-706. [PMID: 24053726 PMCID: PMC3870906 DOI: 10.1021/cb400589q] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 09/20/2013] [Indexed: 01/10/2023]
Abstract
In this work, we present a novel 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) radical phosphoramidite building block, which can be attached to the 5'-terminus of nucleic acids. To investigate the paramagnetic relaxation enhancement (PRE) emanating from this radical center, we incorporated the TEMPO label into various types of RNAs. We measured proton PREs for selectively (13)C-isotope labeled nucleotides to derive long-range distance restraints in a short 15 nucleotide stem-loop model system, underscoring the potential of the 5'-TEMPO tag to determine long-range distance restraints for solution structure determination. We subsequently applied the distance-dependent relaxation enhancement induced by the nitroxide radical to discern two folding states in a bistable RNA. Finally, we investigated the fast conformational sampling of the HIV-1 TAR RNA, a paradigm for structural flexibility in nucleic acids. With PRE NMR in combination with molecular dynamics simulations, the structural plasticity of this RNA was analyzed in the absence and presence of the ligand L-argininamide.
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Affiliation(s)
- Christoph
H. Wunderlich
- Institute
of Organic Chemistry and Center for Molecular Biosciences Innsbruck
(CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Roland G. Huber
- Institute
of General, Inorganic and Theoretical Chemistry and Center for Molecular
Biosciences Innsbruck (CMBI), University
of Innsbruck, Innrain
80/82, 6020 Innsbruck, Austria
| | - Romana Spitzer
- Institute
of Organic Chemistry and Center for Molecular Biosciences Innsbruck
(CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Klaus R. Liedl
- Institute
of General, Inorganic and Theoretical Chemistry and Center for Molecular
Biosciences Innsbruck (CMBI), University
of Innsbruck, Innrain
80/82, 6020 Innsbruck, Austria
| | - Karin Kloiber
- Institute
of Organic Chemistry and Center for Molecular Biosciences Innsbruck
(CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Christoph Kreutz
- Institute
of Organic Chemistry and Center for Molecular Biosciences Innsbruck
(CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
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30
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Site-directed spin-labeling of nucleotides and the use of in-cell EPR to determine long-range distances in a biologically relevant environment. Nat Protoc 2012; 8:131-47. [PMID: 23257982 DOI: 10.1038/nprot.2012.136] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Double electron-electron resonance (DEER) is an electron paramagnetic resonance (EPR) technique used to determine distance distributions in the nanometer range between spin labels by measuring their dipole-dipole interactions. Here we describe how in-cell DEER can be applied to spin-labeled DNA sequences to unravel their conformations in living cells by long-range distance measurements in cellula. As EPR detects unpaired electron spins only, diamagnetic molecules provide no background and do not reduce detection sensitivity of the specific signal. Compared with in-cell NMR spectroscopy, low concentrations of spin-labeled molecules can be used owing to the higher sensitivity of EPR per spin. This protocol describes the synthesis of the spin labels, their introduction in DNA strands, the injection of labeled DNA solutions in cells and the performance of in-cell EPR measurements. Completion of the entire protocol takes ~20 d.
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31
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32
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Kaminker I, Yagi H, Huber T, Feintuch A, Otting G, Goldfarb D. Spectroscopic selection of distance measurements in a protein dimer with mixed nitroxide and Gd3+ spin labels. Phys Chem Chem Phys 2012; 14:4355-8. [DOI: 10.1039/c2cp40219j] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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33
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Atsumi H, Maekawa K, Nakazawa S, Shiomi D, Sato K, Kitagawa M, Takui T, Nakatani K. Tandem Arrays of TEMPO and Nitronyl Nitroxide Radicals with Designed Arrangements on DNA. Chemistry 2011; 18:178-83. [DOI: 10.1002/chem.201102693] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Indexed: 12/24/2022]
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34
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Rublack N, Nguyen H, Appel B, Springstubbe D, Strohbach D, Müller S. Synthesis of specifically modified oligonucleotides for application in structural and functional analysis of RNA. J Nucleic Acids 2011; 2011:805253. [PMID: 22013508 PMCID: PMC3195551 DOI: 10.4061/2011/805253] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2011] [Revised: 07/11/2011] [Accepted: 07/21/2011] [Indexed: 01/30/2023] Open
Abstract
Nowadays, RNA synthesis has become an essential tool not only in the field of molecular biology and medicine, but also in areas like molecular diagnostics and material sciences. Beyond synthetic RNAs for antisense, aptamer, ribozyme, and siRNA technologies, oligoribonucleotides carrying site-specific modifications for structure and function studies are needed. This often requires labeling of the RNA with a suitable spectroscopic reporter group. Herein, we describe the synthesis of functionalized monomer building blocks that upon incorporation in RNA allow for selective reaction with a specific reporter or functional entity. In particular, we report on the synthesis of 5′-O-dimethoxytrityl-2′-O-tert-butyldimethylsilyl protected 3′-O-phosphoramidites of nucleosides that carry amino linkers of different lengths and flexibility at the heterocyclic base, their incorporation in a variety of RNAs, and postsynthetic conjugation with fluorescent dyes and nitroxide spin labels. Further, we show the synthesis of a flavine mononucleotide-N-hydroxy-succinimidyl ester and its conjugation to amino functionalized RNA.
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Affiliation(s)
- Nico Rublack
- Ernst-Moritz-Arndt-Universität Greifswald, Institut für Biochemie, Felix-Hausdorff-Stra β e 4, 17487 Greifswald, Germany
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35
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Nguyen P, Qin PZ. RNA dynamics: perspectives from spin labels. WILEY INTERDISCIPLINARY REVIEWS-RNA 2011; 3:62-72. [PMID: 21882345 DOI: 10.1002/wrna.104] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Dynamics are important and indispensible physical attributes that play essential roles in RNA function. RNA dynamics are complex, spanning vast timescales, and encompassing a large number of physical modes. The technique of site-directed spin labeling (SDSL), which derives information on local structural and dynamic features of a macromolecule by monitoring a chemically stable nitroxide radical using electron paramagnetic resonance spectroscopy, has been applied to monitor intrinsic dynamics at defined structural states as well as to probe conformational transition dynamics of RNAs. The current state of SDSL studies of RNA dynamics is summarized here. Further development and application of SDSL promise to open up many more opportunities for probing RNA dynamics and connecting dynamics to structure and function.
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Affiliation(s)
- Phuong Nguyen
- Department of Chemistry, University of Southern California, Los Angeles, CA, USA
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36
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Sezer D, Sigurdsson ST. Simulating electron spin resonance spectra of macromolecules labeled with two dipolar-coupled nitroxide spin labels from trajectories. Phys Chem Chem Phys 2011; 13:12785-97. [PMID: 21691643 DOI: 10.1039/c1cp20430k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An efficient method for simulating continuous-wave electron spin resonance spectra (ESR) of molecules labeled with two dipolar-coupled nitroxides from trajectories of the molecular motion is presented. Two approximate treatments of the dipolar spin evolution, resulting in significantly shorter simulation times, are examined in order to determine their range of applicability. The approach is illustrated in the context of a double-helical B-DNA. ESR spectra for DNA undergoing anisotropic global diffusion and internal stretching dynamics are calculated for three different labeling geometries with the spin labels bracketing, respectively, three, two and one base pairs. While multifrequency spectra of all three labeling schemes are very sensitive to DNA tumbling, the last one is found to be most informative about the local DNA dynamics.
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Affiliation(s)
- Deniz Sezer
- Faculty of Engineering and Natural Sciences, Sabancı University, Orhanlı-Tuzla, 34956 Istanbul, Turkey.
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37
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Krstić I, Hänsel R, Romainczyk O, Engels JW, Dötsch V, Prisner TF. Long-Range Distance Measurements on Nucleic Acids in Cells by Pulsed EPR Spectroscopy. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201100886] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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38
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Krstić I, Hänsel R, Romainczyk O, Engels JW, Dötsch V, Prisner TF. Long-range distance measurements on nucleic acids in cells by pulsed EPR spectroscopy. Angew Chem Int Ed Engl 2011; 50:5070-4. [PMID: 21506223 DOI: 10.1002/anie.201100886] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Indexed: 12/18/2022]
Affiliation(s)
- Ivan Krstić
- Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt am Main, Germany
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39
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Campagne S, Gervais V, Milon A. Nuclear magnetic resonance analysis of protein-DNA interactions. J R Soc Interface 2011; 8:1065-78. [PMID: 21389020 DOI: 10.1098/rsif.2010.0543] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Recent methodological and instrumental advances in solution-state nuclear magnetic resonance have opened up the way to investigating challenging problems in structural biology such as large macromolecular complexes. This review focuses on the experimental strategies currently employed to solve structures of protein-DNA complexes and to analyse their dynamics. It highlights how these approaches can help in understanding detailed molecular mechanisms of target recognition.
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Affiliation(s)
- S Campagne
- Université de Toulouse, UPS, Department of Structural Biology and Biophysics, F-31077 Toulouse, France
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40
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Dominguez C, Schubert M, Duss O, Ravindranathan S, Allain FHT. Structure determination and dynamics of protein-RNA complexes by NMR spectroscopy. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2011; 58:1-61. [PMID: 21241883 DOI: 10.1016/j.pnmrs.2010.10.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Accepted: 04/24/2010] [Indexed: 05/30/2023]
Affiliation(s)
- Cyril Dominguez
- Institute for Molecular Biology and Biophysics, ETH Zürich, CH-8093 Zürich, Switzerland
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41
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Abstract
RNA requires helical motion to fold and carry out its function. As RNA helical motion occurs on the nanosecond timescale, the timescale probed by fluorescence dyes, fluorescence polarization anisotropy (FPA) is a simple, yet powerful, technique to study helical dynamics in RNA. With the recent development of several fluorescent base analogs that have a nanosecond timescale lifetime in a duplex, FPA has begun to be used for characterizing RNA dynamics. Using the probe 6-methylisoxanthopterin (6-MI) as an example, we describe the procedure for carrying out FPA experiments on model oligonucleotide systems and in a complex RNA, the Tetrahymena group I intron. For smaller RNA systems, isolating the motion of the target helix from the overall tumbling of the whole RNA system is necessary, and nucleic acids binding proteins can be incorporated into the RNA system to increase the overall size of the system, slow the overall tumbling, and thereby reduce the anisotropy contribution from the overall tumbling to negligible. The procedure for incorporating one such protein, the Lac Repressor, is given as an example.
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42
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Edwards TE, Cekan P, Reginsson GW, Shelke SA, Ferré-D'Amaré AR, Schiemann O, Sigurdsson ST. Crystal structure of a DNA containing the planar, phenoxazine-derived bi-functional spectroscopic probe C. Nucleic Acids Res 2011; 39:4419-26. [PMID: 21252294 PMCID: PMC3105401 DOI: 10.1093/nar/gkr015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Previously, we developed the deoxycytosine analog Ç (C-spin) as a bi-functional spectroscopic probe for the study of nucleic acid structure and dynamics using electron paramagnetic resonance (EPR) and fluorescence spectroscopy. To understand the effect of Ç on nucleic acid structure, we undertook a detailed crystallographic analysis. A 1.7 Å resolution crystal structure of Ç within a decamer duplex A-form DNA confirmed that Ç forms a non-perturbing base pair with deoxyguanosine, as designed. In the context of double-stranded DNA Ç adopted a planar conformation. In contrast, a crystal structure of the free spin-labeled base ç displayed a ∼ 20° bend at the oxazine linkage. Density function theory calculations revealed that the bent and planar conformations are close in energy and exhibit the same frequency for bending. These results indicate a small degree of flexibility around the oxazine linkage, which may be a consequence of the antiaromaticity of a 16-π electron ring system. Within DNA, the amplitude of the bending motion is restricted, presumably due to base-stacking interactions. This structural analysis shows that the Ç forms a planar, structurally non-perturbing base pair with G indicating it can be used with high confidence in EPR- or fluorescence-based structural and dynamics studies.
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43
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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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44
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Sicoli G, Wachowius F, Bennati M, Höbartner C. Probing secondary structures of spin-labeled RNA by pulsed EPR spectroscopy. Angew Chem Int Ed Engl 2010; 49:6443-7. [PMID: 20665607 DOI: 10.1002/anie.201000713] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Giuseppe Sicoli
- Research group Electron Paramagnetic Resonance, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
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45
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Kim NK, Bowman MK, DeRose VJ. Precise mapping of RNA tertiary structure via nanometer distance measurements with double electron-electron resonance spectroscopy. J Am Chem Soc 2010; 132:8882-4. [PMID: 20557039 DOI: 10.1021/ja101317g] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Divalent metal (Mg(2+)) ion-dependent folding of the hammerhead ribozyme from Schistosoma mansoni was monitored with double electron-electron resonance (DEER) pulsed electron paramagnetic resonance spectroscopy by measuring nanometer-scale distances between paramagnetic spin-labels attached to the RNA. DEER measurements detect global folding of the ribozyme with excellent agreement between predictions from experimental, modeled, and crystallographic measurements. These measurements demonstrate the use of DEER spectroscopy as a tool for structural analysis of complex RNAs.
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Affiliation(s)
- Nak-Kyoon Kim
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, USA
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46
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Sicoli G, Wachowius F, Bennati M, Höbartner C. Sekundärstrukturanalyse von spinmarkierter RNA mit Puls-EPR-Spektroskopie. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201000713] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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47
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Leeper TC, Qu X, Lu C, Moore C, Varani G. Novel protein-protein contacts facilitate mRNA 3'-processing signal recognition by Rna15 and Hrp1. J Mol Biol 2010; 401:334-49. [PMID: 20600122 DOI: 10.1016/j.jmb.2010.06.032] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 06/10/2010] [Accepted: 06/10/2010] [Indexed: 12/22/2022]
Abstract
Precise 3'-end processing of mRNA is essential for correct gene expression, yet in yeast, 3'-processing signals consist of multiple ambiguous sequence elements. Two neighboring elements upstream of the cleavage site are particularly important for the accuracy (positioning element) and efficiency (efficiency element) of 3'-processing and are recognized by the RNA-binding proteins Rna15 and Hrp1, respectively. In vivo, these interactions are strengthened by the scaffolding protein Rna14 that stabilizes their association. The NMR structure of the 34 -kDa ternary complex of the RNA recognition motif (RRM) domains of Hrp1 and Rna15 bound to this pair of RNA elements was determined by residual dipolar coupling and paramagnetic relaxation experiments. It reveals how each of the proteins binds to RNA and introduces a novel class of protein-protein contact in regions of previously unknown function. These interdomain contacts had previously been overlooked in other multi-RRM structures, although a careful analysis suggests that they may be frequently present. Mutations in the regions of these contacts disrupt 3'-end processing, suggesting that they may structurally organize the ribonucleoprotein complexes responsible for RNA processing.
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Affiliation(s)
- Thomas C Leeper
- Department of Chemistry, University of Washington, Seattle, WA 98195-1700, USA.
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48
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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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49
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Marko A, Margraf D, Cekan P, Sigurdsson ST, Schiemann O, Prisner TF. Analytical method to determine the orientation of rigid spin labels in DNA. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 81:021911. [PMID: 20365599 DOI: 10.1103/physreve.81.021911] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Indexed: 05/29/2023]
Abstract
We demonstrate the ability of pulsed electron double resonance (PELDOR) experiments to determine the orientation of spin labels in biological macromolecules. Thus, the distance information usually obtained from PELDOR data can be complemented by the mutual orientation of macromolecular domains. A method to determine the angle beta between the spin label normal and the interspin axis is proposed and analyzed mathematically. The obtained analytical expression allows extraction of angles beta without a fitting procedure if these angles are equal for both nitroxide of biradical. The method was applied to the experimental data gathered on ten spin-labeled DNA samples. The angles estimated from the PELDOR data are in excellent agreement with literature values.
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Affiliation(s)
- Andriy Marko
- Institute of Physical and Theoretical Chemistry, J. W. Goethe University, Max-von-Laue-Str. 7, D-60438 Frankfurt, Germany.
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50
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Su XC, Otting G. Paramagnetic labelling of proteins and oligonucleotides for NMR. JOURNAL OF BIOMOLECULAR NMR 2010; 46:101-112. [PMID: 19529883 DOI: 10.1007/s10858-009-9331-1] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2009] [Accepted: 05/20/2009] [Indexed: 05/26/2023]
Abstract
Paramagnetic effects offer a rich source of long-range structural restraints. Here we review current methods for site-specific tagging of proteins and oligonucleotides with paramagnetic molecules. The paramagnetic tags include nitroxide radicals and metal chelators. Particular emphasis is placed on tags suitable for site-specific and rigid attachment of lanthanide ions to macromolecules.
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Affiliation(s)
- Xun-Cheng Su
- The Australian National University, Canberra, Australia
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