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Chubarov AS, Endeward B, Kanarskaya MA, Polienko YF, Prisner TF, Lomzov AA. Pulsed Dipolar EPR for Self-Limited Complexes of Oligonucleotides Studies. Biomolecules 2024; 14:887. [PMID: 39199275 DOI: 10.3390/biom14080887] [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: 05/31/2024] [Revised: 07/16/2024] [Accepted: 07/18/2024] [Indexed: 09/01/2024] Open
Abstract
Pulsed electron-electron double resonance (PELDOR) spectroscopy is a powerful method for determining nucleic acid (NA) structure and conformational dynamics. PELDOR with molecular dynamics (MD) simulations opens up unique possibilities for defining the conformational ensembles of flexible, three-dimensional, self-assembled complexes of NA. Understanding the diversity and structure of these complexes is vital for uncovering matrix and regulative biological processes in the human body and artificially influencing them for therapeutic purposes. To explore the reliability of PELDOR and MD simulations, we site-specifically attached nitroxide spin labels to oligonucleotides, which form self-assembled complexes between NA chains and exhibit significant conformational flexibility. The DNA complexes assembled from a pair of oligonucleotides with different linker sizes showed excellent agreement between the distance distributions obtained from PELDOR and calculated from MD simulations, both for the mean inter-spin distance and the distance distribution width. These results prove that PELDOR with MD simulations has significant potential for studying the structure and dynamics of conformational flexible complexes of NA.
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Affiliation(s)
- Alexey S Chubarov
- Institute of Chemical Biology and Fundamental Medicine SB RAS, 630090 Novosibirsk, Russia
| | - Burkhard Endeward
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt am Main, Germany
| | - Maria A Kanarskaya
- Institute of Chemical Biology and Fundamental Medicine SB RAS, 630090 Novosibirsk, Russia
| | - Yuliya F Polienko
- N.N. Vorozhtsov Institute of Organic Chemistry SB RAS, 630090 Novosibirsk, Russia
| | - Thomas F Prisner
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt am Main, Germany
| | - Alexander A Lomzov
- Institute of Chemical Biology and Fundamental Medicine SB RAS, 630090 Novosibirsk, Russia
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2
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Kuzin S, Stolba D, Wu X, Syryamina VN, Boulos S, Jeschke G, Nyström L, Yulikov M. Quantification of Distributions of Local Proton Concentrations in Heterogeneous Soft Matter and Non-Anfinsen Biomacromolecules. J Phys Chem Lett 2024; 15:5625-5632. [PMID: 38758534 PMCID: PMC11145652 DOI: 10.1021/acs.jpclett.4c00825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 05/13/2024] [Accepted: 05/15/2024] [Indexed: 05/18/2024]
Abstract
A new method to quantitatively analyze heterogeneous distributions of local proton densities around paramagnetic centers in unstructured and weakly structured biomacromolecules and soft matter is introduced, and its feasibility is demonstrated on aqueous solutions of stochastically spin-labeled polysaccharides. This method is based on the pulse EPR experiment ih-RIDME (intermolecular hyperfine relaxation-induced dipolar modulation enhancement). Global analysis of a series of RIDME traces allows for a mathematically stable transformation of the time-domain data to the distribution of local proton concentrations. Two pulse sequences are proposed and tested, which combine the ih-RIDME block and the double-electron-electron resonance (DEER) experiment. Such experiments can be potentially used to correlate the local proton concentration with the macromolecular chain conformation. We anticipate an application of this approach in studies of intrinsically disordered proteins, biomolecular aggregates, and biomolecular condensates.
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Affiliation(s)
- Sergei Kuzin
- Department
of Chemistry and Applied Biosciences, ETH
Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Dario Stolba
- Department
of Chemistry and Applied Biosciences, ETH
Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Xiaowen Wu
- Department
of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092 Zurich, Switzerland
- Max
Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
| | - Victoria N. Syryamina
- Department
of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092 Zurich, Switzerland
- Voevodsky
Institute of Chemical Kinetics and Combustion, Novosibirsk 630090, Russia
| | - Samy Boulos
- Department
of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092 Zurich, Switzerland
| | - Gunnar Jeschke
- Department
of Chemistry and Applied Biosciences, ETH
Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Laura Nyström
- Department
of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092 Zurich, Switzerland
| | - Maxim Yulikov
- Department
of Chemistry and Applied Biosciences, ETH
Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
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3
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Jaufer AM, Bouhadana A, Kharrazizadeh A, Zhou M, Colina CM, Fanucci GE. Designing surface exposed sites on Bacillus subtilis lipase A for spin-labeling and hydration studies. Biophys Chem 2024; 308:107203. [PMID: 38382282 DOI: 10.1016/j.bpc.2024.107203] [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: 01/19/2024] [Revised: 02/09/2024] [Accepted: 02/15/2024] [Indexed: 02/23/2024]
Abstract
Spin-labeling with electron paramagnetic resonance spectroscopy (EPR) is a facile method for interrogating macromolecular flexibility, conformational changes, accessibility, and hydration. Within we present a computationally based approach for the rational selection of reporter sites in Bacillus subtilis lipase A (BSLA) for substitution to cysteine residues with subsequent modification with a spin-label that are expected to not significantly perturb the wild-type structure, dynamics, or enzymatic function. Experimental circular dichroism spectroscopy, Michaelis-Menten kinetic parameters and EPR spectroscopy data validate the success of this approach to computationally select reporter sites for future magnetic resonance investigations of hydration and hydration changes induced by polymer conjugation, tethering, immobilization, or amino acid substitution in BSLA. Analysis of molecular dynamic simulations of the impact of substitutions on the secondary structure agree well with experimental findings. We propose that this computationally guided approach for choosing spin-labeled EPR reporter sites, which evaluates relative surface accessibility coupled with hydrogen bonding occupancy of amino acids to the catalytic pocket via atomistic simulations, should be readily transferable to other macromolecular systems of interest including selecting sites for paramagnetic relaxation enhancement NMR studies, other spin-labeling EPR studies or any method requiring a tagging method where it is desirable to not alter enzyme stability or activity.
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Affiliation(s)
- Afnan M Jaufer
- Department of Chemistry, University of Florida, PO BOX 117200, Gainesville, FL 32611, USA; George and Josephine Butler Polymer Research Laboratory, University of Florida, Gainesville, FL 32611, USA.
| | - Adam Bouhadana
- Department of Chemistry, University of Florida, PO BOX 117200, Gainesville, FL 32611, USA.
| | - Amir Kharrazizadeh
- Department of Chemistry, University of Florida, PO BOX 117200, Gainesville, FL 32611, USA.
| | - Mingwei Zhou
- Department of Chemistry, University of Florida, PO BOX 117200, Gainesville, FL 32611, USA.
| | - Coray M Colina
- Department of Chemistry, University of Florida, PO BOX 117200, Gainesville, FL 32611, USA; George and Josephine Butler Polymer Research Laboratory, University of Florida, Gainesville, FL 32611, USA; Department of Materials Science and Engineering, University of Florida, PO BOX 117200, Gainesville, FL 32611, USA.
| | - Gail E Fanucci
- Department of Chemistry, University of Florida, PO BOX 117200, Gainesville, FL 32611, USA.
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4
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Awad SI, Smadi OA, Tomeh MF, Alzghoul SM. A guideline for the distance measurement plans of site-directed spin labels for structural prediction of nucleic acids. J Mol Model 2023; 30:16. [PMID: 38157075 DOI: 10.1007/s00894-023-05808-w] [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: 06/12/2023] [Accepted: 12/11/2023] [Indexed: 01/03/2024]
Abstract
CONTEXT AND RESULTS Site-directed spin labeling (SDSL) combined with electron paramagnetic resonance spectroscopy methods has been successfully used to predict the structures of nucleic acids. These methods measure the distances between spin labels yielding distance equations that are solved using numerical algorithms to provide one or several structural predictions. In this work, the minimum number of SDSL distance measurements and distance measurement types required to predict a unique nucleic acid structure were investigated. Our results indicate that at least six distance measurements should be obtained given that the distance measurements do not connect one SDSL on one arm with more than three SDSLs on the other arm. Moreover, there may be a preference for 1-to-1 SLs distance measurements rather than 1-to-many SLs as the latter was linked to undefined structures discussed in this study. METHODS Pairs of double-helical arms of nucleic acid were simulated using the finite element software Pro/ENGINEER (PTC Inc., Boston, MA). In each simulation, a specific SDSL distance measurement plan was adopted and the resulting structure was tested for movability. Immovable structures indicate that this plan will potentially result in a unique structural prediction of the nucleic acid. All the possible plans for SDSL distance measurements were investigated either by direct measurement or by extrapolation.
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Affiliation(s)
- Samer I Awad
- Department of Biomedical Engineering, Faculty of Engineering, The Hashemite University, P.O. Box 330127, Zarqa, 13133, Jordan.
| | - Othman A Smadi
- Department of Biomedical Engineering, Faculty of Engineering, The Hashemite University, P.O. Box 330127, Zarqa, 13133, Jordan
| | - Mohammed F Tomeh
- Department of Industrial Engineering, Faculty of Engineering, The Hashemite University, P.O. Box 330127, Zarqa, 13133, Jordan
| | - Salah M Alzghoul
- Department of Biomedical Engineering, Faculty of Engineering, The Hashemite University, P.O. Box 330127, Zarqa, 13133, Jordan
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5
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Bertran A, Morbiato L, Sawyer J, Dalla Torre C, Heyes DJ, Hay S, Timmel CR, Di Valentin M, De Zotti M, Bowen AM. Direct Comparison between Förster Resonance Energy Transfer and Light-Induced Triplet-Triplet Electron Resonance Spectroscopy. J Am Chem Soc 2023; 145:22859-22865. [PMID: 37839071 PMCID: PMC10603778 DOI: 10.1021/jacs.3c04685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Indexed: 10/17/2023]
Abstract
To carry out reliable and comprehensive structural investigations, the exploitation of different complementary techniques is required. Here, we report that dual triplet-spin/fluorescent labels enable the first parallel distance measurements by electron spin resonance (ESR) and Förster resonance energy transfer (FRET) on exactly the same molecules with orthogonal chromophores, allowing for direct comparison. An improved light-induced triplet-triplet electron resonance method with 2-color excitation is used, improving the signal-to-noise ratio of the data and yielding a distance distribution that provides greater insight than the single distance resulting from FRET.
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Affiliation(s)
- Arnau Bertran
- Centre
for Advanced Electron Spin Resonance and Inorganic Chemistry Laboratory,
Department of Chemistry, University of Oxford, Oxford OX1 3QR, United Kingdom
| | - Laura Morbiato
- Department
of Chemical Sciences, University of Padova, 35131 Padova, Italy
| | - Jack Sawyer
- The
National Research Facility for Electron Paramagnetic Resonance, Department
of Chemistry, Manchester Institute of Biotechnology and Photon Science
Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Chiara Dalla Torre
- Department
of Chemical Sciences, University of Padova, 35131 Padova, Italy
| | - Derren J. Heyes
- The
National Research Facility for Electron Paramagnetic Resonance, Department
of Chemistry, Manchester Institute of Biotechnology and Photon Science
Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Sam Hay
- The
National Research Facility for Electron Paramagnetic Resonance, Department
of Chemistry, Manchester Institute of Biotechnology and Photon Science
Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Christiane R. Timmel
- Centre
for Advanced Electron Spin Resonance and Inorganic Chemistry Laboratory,
Department of Chemistry, University of Oxford, Oxford OX1 3QR, United Kingdom
| | - Marilena Di Valentin
- Department
of Chemical Sciences, University of Padova, 35131 Padova, Italy
- Centro
Interdipartimentale di Ricerca “Centro Studi di Economia e
Tecnica dell’energia Giorgio Levi Cases”, 35131 Padova, Italy
| | - Marta De Zotti
- Department
of Chemical Sciences, University of Padova, 35131 Padova, Italy
- Centro
Interdipartimentale di Ricerca “Centro Studi di Economia e
Tecnica dell’energia Giorgio Levi Cases”, 35131 Padova, Italy
| | - Alice M. Bowen
- The
National Research Facility for Electron Paramagnetic Resonance, Department
of Chemistry, Manchester Institute of Biotechnology and Photon Science
Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
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6
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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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7
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Sannikova NE, Kolokolov MI, Khlynova TA, Chubarov AS, Polienko YF, Fedin MV, Krumkacheva OA. Revealing light-induced structural shifts in G-quadruplex-porphyrin complexes: a pulsed dipolar EPR study. Phys Chem Chem Phys 2023; 25:22455-22466. [PMID: 37581249 DOI: 10.1039/d3cp01775c] [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: 08/16/2023]
Abstract
The binding of G-quadruplex structures (G4s) with photosensitizers is of considerable importance in medicinal chemistry and drug discovery due to their promising potential in photodynamic therapy applications. G4s can experience structural changes as a result of ligand interactions and light exposure. Understanding these modifications is essential to uncover the fundamental biological roles of the complexes and optimize their therapeutic potential. The structural diversity of G4s makes it challenging to study their complexes with ligands, necessitating the use of various complementary methods to fully understand these interactions. In this study, we introduce, for the first time, the application of laser-induced dipolar EPR as a method to characterize G-quadruplex DNA complexes containing photosensitizers and to investigate light-induced structural modifications in these systems. To demonstrate the feasibility of this approach, we studied complexes of the human telomeric G-quadruplex (HTel-22) with cationic 5,10,15,20-tetrakis(1-methyl-4-pyridinio) porphyrin tetra(p-toluenesulfonate) (TMPyP4). In addition to showcasing a new methodology, we also aimed to provide insights into the mechanisms underlying photoinduced HTel-22/TMPyP4 structural changes, thereby aiding in the advancement of approaches targeting G4s in photodynamic therapy. EPR revealed G-quadruplex unfolding and dimer formation upon light exposure. Our findings demonstrate the potential of EPR spectroscopy for examining G4 complexes with photosensitizers and contribute to a better understanding of G4s' interactions with ligands under light.
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Affiliation(s)
- Natalya E Sannikova
- International Tomography Center SB RAS, 630090 Novosibirsk, Russia.
- Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russia
| | - Mikhail I Kolokolov
- International Tomography Center SB RAS, 630090 Novosibirsk, Russia.
- Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russia
| | - Tamara A Khlynova
- International Tomography Center SB RAS, 630090 Novosibirsk, Russia.
- Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russia
| | - Alexey S Chubarov
- Institute of Chemical Biology and Fundamental Medicine SB RAS, Novosibirsk 630090, Russia
- Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russia
| | - Yuliya F Polienko
- N.N. Vorozhtsov Institute of Organic Chemistry SB RAS, 630090 Novosibirsk, Russia
| | - Matvey V Fedin
- International Tomography Center SB RAS, 630090 Novosibirsk, Russia.
- Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russia
| | - Olesya A Krumkacheva
- International Tomography Center SB RAS, 630090 Novosibirsk, Russia.
- Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russia
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8
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Wort JL, Ackermann K, Giannoulis A, Bode BE. Enhanced sensitivity for pulse dipolar EPR spectroscopy using variable-time RIDME. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 352:107460. [PMID: 37167826 DOI: 10.1016/j.jmr.2023.107460] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 04/03/2023] [Accepted: 04/19/2023] [Indexed: 05/13/2023]
Abstract
Pulse dipolar EPR spectroscopy (PDS) measurements are an important complementary tool in structural biology and are increasingly applied to macromolecular assemblies implicated in human health and disease at physiological concentrations. This requires ever higher sensitivity, and recent advances have driven PDS measurements into the mid-nanomolar concentration regime, though optimization and acquisition of such measurements remains experimentally demanding and time expensive. One important consideration is that constant-time acquisition represents a hard limit for measurement sensitivity, depending on the maximum measured distance. Determining this distance a priori has been facilitated by machine-learning structure prediction (AlphaFold2 and RoseTTAFold) but is often confounded by non-representative behaviour in frozen solution that may mandate multiple rounds of optimization and acquisition. Herein, we endeavour to simultaneously enhance sensitivity and streamline PDS measurement optimization to one-step by benchmarking a variable-time acquisition RIDME experiment applied to CuII-nitroxide and CuII-CuII model systems. Results demonstrate marked sensitivity improvements of both 5- and 6-pulse variable-time RIDME of between 2- and 5-fold over the constant-time analogues.
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Affiliation(s)
- Joshua L Wort
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Scotland
| | - Katrin Ackermann
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Scotland
| | - Angeliki Giannoulis
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Scotland
| | - Bela E Bode
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Scotland.
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9
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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: 1] [Impact Index Per Article: 1.0] [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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10
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Pierro A, Drescher M. Dance with spins: site-directed spin labeling coupled to electron paramagnetic resonance spectroscopy directly inside cells. Chem Commun (Camb) 2023; 59:1274-1284. [PMID: 36633152 PMCID: PMC9890500 DOI: 10.1039/d2cc05907j] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 01/04/2023] [Indexed: 01/06/2023]
Abstract
Depicting how biomolecules move and interact within their physiological environment is one of the hottest topics of structural biology. This Feature Article gives an overview of the most recent advances in Site-directed Spin Labeling coupled to Electron Paramagnetic Resonance spectroscopy (SDSL-EPR) to study biomolecules in living cells. The high sensitivity, the virtual absence of background, and the versatility of spin-labeling strategies make this approach one of the most promising techniques for the study of biomolecules in physiologically relevant environments. After presenting the milestones achieved in this field, we present a summary of the future goals and ambitions of this community.
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Affiliation(s)
- Annalisa Pierro
- Department of Chemistry, University of Konstanz, and Konstanz Research School Chemical Biology, Universitätsstraße 10, 78457 Konstanz, Germany.
| | - Malte Drescher
- Department of Chemistry, University of Konstanz, and Konstanz Research School Chemical Biology, Universitätsstraße 10, 78457 Konstanz, Germany.
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11
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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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12
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Hofmann L, Mandato A, Saxena S, Ruthstein S. The use of EPR spectroscopy to study transcription mechanisms. Biophys Rev 2022; 14:1141-1159. [PMID: 36345280 PMCID: PMC9636360 DOI: 10.1007/s12551-022-01004-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 09/26/2022] [Indexed: 02/08/2023] Open
Abstract
Electron paramagnetic resonance (EPR) spectroscopy has become a promising structural biology tool to resolve complex and dynamic biological mechanisms in-vitro and in-cell. Here, we focus on the advantages of continuous wave (CW) and pulsed EPR distance measurements to resolve transcription processes and protein-DNA interaction. The wide range of spin-labeling approaches that can be used to follow structural changes in both protein and DNA render EPR a powerful method to study protein-DNA interactions and structure-function relationships in other macromolecular complexes. EPR-derived data goes well beyond static structural information and thus serves as the method of choice if dynamic insight is needed. Herein, we describe the conceptual details of the theory and the methodology and illustrate the use of EPR to study the protein-DNA interaction of the copper-sensitive transcription factor, CueR.
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Affiliation(s)
- L. Hofmann
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat-Gan, Israel
| | - A. Mandato
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA USA
| | - S. Saxena
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA USA
| | - S. Ruthstein
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat-Gan, Israel
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13
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Besaw JE, Reichenwallner J, De Guzman P, Tucs A, Kuo A, Morizumi T, Tsuda K, Sljoka A, Miller RJD, Ernst OP. Low pH structure of heliorhodopsin reveals chloride binding site and intramolecular signaling pathway. Sci Rep 2022; 12:13955. [PMID: 35977989 PMCID: PMC9385722 DOI: 10.1038/s41598-022-17716-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 07/29/2022] [Indexed: 11/11/2022] Open
Abstract
Within the microbial rhodopsin family, heliorhodopsins (HeRs) form a phylogenetically distinct group of light-harvesting retinal proteins with largely unknown functions. We have determined the 1.97 Å resolution X-ray crystal structure of Thermoplasmatales archaeon SG8-52-1 heliorhodopsin (TaHeR) in the presence of NaCl under acidic conditions (pH 4.5), which complements the known 2.4 Å TaHeR structure acquired at pH 8.0. The low pH structure revealed that the hydrophilic Schiff base cavity (SBC) accommodates a chloride anion to stabilize the protonated retinal Schiff base when its primary counterion (Glu-108) is neutralized. Comparison of the two structures at different pH revealed conformational changes connecting the SBC and the extracellular loop linking helices A-B. We corroborated this intramolecular signaling transduction pathway with computational studies, which revealed allosteric network changes propagating from the perturbed SBC to the intracellular and extracellular space, suggesting TaHeR may function as a sensory rhodopsin. This intramolecular signaling mechanism may be conserved among HeRs, as similar changes were observed for HeR 48C12 between its pH 8.8 and pH 4.3 structures. We additionally performed DEER experiments, which suggests that TaHeR forms possible dimer-of-dimer associations which may be integral to its putative functionality as a light sensor in binding a transducer protein.
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Affiliation(s)
- Jessica E Besaw
- Department of Chemistry, University of Toronto, Toronto, ON, M5S 3H6, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Jörg Reichenwallner
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Paolo De Guzman
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
- Department of Laboratory Medicine and Pathology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Andrejs Tucs
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, 277-8561, Japan
| | - Anling Kuo
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Takefumi Morizumi
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Koji Tsuda
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, 277-8561, Japan
- RIKEN Center for Advanced Intelligence Project, RIKEN, 1-4-1 Nihombashi, Chuo-ku, Tokyo, 103-0027, Japan
- Research and Services Division of Materials Data and Integrated System, National Institute for Materials Science, Tsukuba, Ibaraki, 305-0047, Japan
| | - Adnan Sljoka
- RIKEN Center for Advanced Intelligence Project, RIKEN, 1-4-1 Nihombashi, Chuo-ku, Tokyo, 103-0027, Japan.
- Department of Chemistry, York University, Toronto, ON, M3J 1P3, Canada.
| | - R J Dwayne Miller
- Department of Chemistry, University of Toronto, Toronto, ON, M5S 3H6, Canada
- Department of Physics, University of Toronto, Toronto, ON, M5S 3H6, Canada
| | - Oliver P Ernst
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.
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