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Strzelecki P, Shpiruk A, Cech GM, Kloska A, Hébraud P, Beyer N, Busi F, Grange W. Robust, high-yield, rapid fabrication of DNA constructs for Magnetic Tweezers. Biochem Biophys Res Commun 2024; 731:150370. [PMID: 39047619 DOI: 10.1016/j.bbrc.2024.150370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2024] [Accepted: 07/05/2024] [Indexed: 07/27/2024]
Abstract
Single-molecule techniques are highly sensitive tools that can reveal reaction intermediates often obscured in experiments involving large ensembles of molecules. Therefore, they provide unprecedented information on the mechanisms that control biomolecular reactions. Currently, one of the most significant single-molecule assays is Magnetic Tweezers (MT), which probes enzymatic reactions at high spatio-temporal resolutions on tens, if not hundreds, of molecules simultaneously. For high-resolution MT experiments, a short double-stranded DNA molecule (less than 2000 base pairs) is typically attached between a micron-sized superparamagnetic bead and a surface. The fabrication of such a substrate is key for successful single-molecule assays, and several papers have discussed the possibility of improving the fabrication of short DNA constructs. However, reported yields are usually low and require additional time-consuming purification steps (e.g., gel purification). In this paper, we propose the use of a Golden Gate Assembly assay that allows for the production of DNA constructs within minutes (starting from PCR products). We discuss how relevant parameters may affect the yield and offer single-molecule experimentalists a simple yet robust approach to fabricate DNA constructs.
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Affiliation(s)
- Patryk Strzelecki
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, F-6700, Strasbourg, France; Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland
| | - Anastasiia Shpiruk
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, F-6700, Strasbourg, France
| | - Grzegorz M Cech
- Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland
| | - Anna Kloska
- Department of Medical Biology and Genetics, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland
| | - Pascal Hébraud
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, F-6700, Strasbourg, France
| | - Nicolas Beyer
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, F-6700, Strasbourg, France
| | - Florent Busi
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, UMR 8251, F-75013, Paris, France; Université Paris Cité, UFR Sciences du vivant, F-75013, Paris, France.
| | - Wilfried Grange
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, F-6700, Strasbourg, France; Université Paris Cité, UFR Sciences du vivant, F-75013, Paris, France.
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2
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Dohnalová H, Seifert M, Matoušková E, Klein M, Papini FS, Lipfert J, Dulin D, Lankaš F. Temperature-Dependent Twist of Double-Stranded RNA Probed by Magnetic Tweezer Experiments and Molecular Dynamics Simulations. J Phys Chem B 2024; 128:664-675. [PMID: 38197365 PMCID: PMC10823466 DOI: 10.1021/acs.jpcb.3c06280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 12/19/2023] [Accepted: 12/20/2023] [Indexed: 01/11/2024]
Abstract
RNA plays critical roles in the transmission and regulation of genetic information and is increasingly used in biomedical and biotechnological applications. Functional RNAs contain extended double-stranded regions, and the structure of double-stranded RNA (dsRNA) has been revealed at high resolution. However, the dependence of the properties of the RNA double helix on environmental effects, notably temperature, is still poorly understood. Here, we use single-molecule magnetic tweezer measurements to determine the dependence of the dsRNA twist on temperature. We find that dsRNA unwinds with increasing temperature, even more than DNA, with ΔTwRNA = -14.4 ± 0.7°/(°C·kbp), compared to ΔTwDNA = -11.0 ± 1.2°/(°C·kbp). All-atom molecular dynamics (MD) simulations using a range of nucleic acid force fields, ion parameters, and water models correctly predict that dsRNA unwinds with rising temperature but significantly underestimate the magnitude of the effect. These MD data, together with additional MD simulations involving DNA and DNA-RNA hybrid duplexes, reveal a linear correlation between the twist temperature decrease and the helical rise, in line with DNA but at variance with RNA experimental data. We speculate that this discrepancy might be caused by some unknown bias in the RNA force fields tested or by as yet undiscovered transient alternative structures in the RNA duplex. Our results provide a baseline to model more complex RNA assemblies and to test and develop new parametrizations for RNA simulations. They may also inspire physical models of the temperature-dependent dsRNA structure.
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Affiliation(s)
- Hana Dohnalová
- Department
of Informatics and Chemistry, University
of Chemistry and Technology Prague, Technická 5, 166 28 Praha
6, Czech Republic
| | - Mona Seifert
- Junior
Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich-Alexander-University Erlangen-Nürnberg, Cauerstr. 3, Erlangen 91058, Germany
| | - Eva Matoušková
- Department
of Informatics and Chemistry, University
of Chemistry and Technology Prague, Technická 5, 166 28 Praha
6, Czech Republic
| | - Misha Klein
- Department
of Physics and Astronomy and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, Amsterdam 1081 HV, The Netherlands
| | - Flávia S. Papini
- Junior
Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich-Alexander-University Erlangen-Nürnberg, Cauerstr. 3, Erlangen 91058, Germany
| | - Jan Lipfert
- Soft
Condensed Matter and Biophysics, Department of Physics and Debye Institute, Utrecht University, Utrecht 3584 CC, The Netherlands
| | - David Dulin
- Junior
Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich-Alexander-University Erlangen-Nürnberg, Cauerstr. 3, Erlangen 91058, Germany
- Department
of Physics and Astronomy and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, Amsterdam 1081 HV, The Netherlands
| | - Filip Lankaš
- Department
of Informatics and Chemistry, University
of Chemistry and Technology Prague, Technická 5, 166 28 Praha
6, Czech Republic
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3
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Valle-Orero J, Rieu M, Allemand JF, Bujaa D, Joubert A, Tran PLT, Croquette V, Boulé JB. Observing G4 formation and its resolution by Pif1 in real time by manipulation under magnetic tweezers. Methods Enzymol 2024; 695:119-158. [PMID: 38521583 DOI: 10.1016/bs.mie.2023.12.012] [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: 03/25/2024]
Abstract
G-quadruplexes (G4s) are nucleic acids secondary structures that may form in guanine-rich sequences, either intra or inter-molecularly. Ability of a primary sequence to form a G4 can be predicted computationally with an improving accuracy as well as tested in bulk using biophysical measurements. As a result, G4 density maps have been devised for a large number of genomes from all life kingdoms. Experimental validation of the formation of G4s in vivo however remains indirect and relies on their stabilization with small molecules, antibodies or proteins, or mutational studies, in order to measure downstream effects on gene expression or genome stability for example. Although numerous techniques exist to observe spontaneous formation of G4s in single-stranded DNA, observing G4 formation in double-stranded DNA (dsDNA) is more challenging. However, it is particularly relevant to understand if a given G4 sequence forms stably in a dsDNA context, if it is stable enough to dock proteins or pose a challenge to molecular motors such as helicases or polymerases. In essence, G4s can be a threat to genomic stability but carry as well as the potential to be elements of a structural language in the non-replicating genome. To study quantitatively the formation dynamics and stability of single intramolecular G4s embedded in dsDNA, we have adapted techniques of DNA manipulation under magnetic tweezers. This technique also allows to study encounters of molecular motors with G4 at a single molecule resolution, in order to gain insight into the specificity of G4 resolution by molecular motors, and its efficiency. The procedures described here include the design of the G4 substrate, the study of G4 formation probability and lifetime in dsDNA, as well as procedures to characterize the encounter between the Pif1 helicase and a G4 until G4 resolution. The procedures that we described here can easily be extended to the study of other G4s or molecular motors.
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Affiliation(s)
- Jessica Valle-Orero
- Physics Laboratory of the École Normale Supérieure, CNRS, ENS, PSL University, Sorbonne University, Paris-Cité University, Paris, France; Biology Institute of the École Normale Supérieure (IBENS), ENS, CNRS, INSERM, PSL University, Paris, France; Department of Computer Science, Mathematics and Environmental Sciences, The American University of Paris, Paris, France.
| | - Martin Rieu
- Physics Laboratory of the École Normale Supérieure, CNRS, ENS, PSL University, Sorbonne University, Paris-Cité University, Paris, France; Biology Institute of the École Normale Supérieure (IBENS), ENS, CNRS, INSERM, PSL University, Paris, France; Department of Physics, University of Oxford, Oxford, United Kingdom
| | - Jean-François Allemand
- Physics Laboratory of the École Normale Supérieure, CNRS, ENS, PSL University, Sorbonne University, Paris-Cité University, Paris, France; Biology Institute of the École Normale Supérieure (IBENS), ENS, CNRS, INSERM, PSL University, Paris, France
| | - Dulamkhuu Bujaa
- Physics Laboratory of the École Normale Supérieure, CNRS, ENS, PSL University, Sorbonne University, Paris-Cité University, Paris, France; Biology Institute of the École Normale Supérieure (IBENS), ENS, CNRS, INSERM, PSL University, Paris, France
| | - Alexandra Joubert
- Genome Structure and Instability Laboratory, National Museum of Natural History, CNRS, INSERM, Sorbonne University Alliance, Paris, France
| | - Phong Lan Thao Tran
- Genome Structure and Instability Laboratory, National Museum of Natural History, CNRS, INSERM, Sorbonne University Alliance, Paris, France; Depixus SAS, 3-5 impasse Reille, Paris, France
| | - Vincent Croquette
- Physics Laboratory of the École Normale Supérieure, CNRS, ENS, PSL University, Sorbonne University, Paris-Cité University, Paris, France; Biology Institute of the École Normale Supérieure (IBENS), ENS, CNRS, INSERM, PSL University, Paris, France; ESPCI Paris, PSL University, Paris, France.
| | - Jean-Baptiste Boulé
- Genome Structure and Instability Laboratory, National Museum of Natural History, CNRS, INSERM, Sorbonne University Alliance, Paris, France.
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4
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Dulin D. An Introduction to Magnetic Tweezers. Methods Mol Biol 2024; 2694:375-401. [PMID: 37824014 DOI: 10.1007/978-1-0716-3377-9_18] [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: 10/13/2023]
Abstract
Magnetic tweezers are a single-molecule force and torque spectroscopy technique that enable the mechanical interrogation in vitro of biomolecules, such as nucleic acids and proteins. They use a magnetic field originating from either permanent magnets or electromagnets to attract a magnetic particle, thus stretching the tethering biomolecule. They nicely complement other force spectroscopy techniques such as optical tweezers and atomic force microscopy (AFM) as they operate as a very stable force clamp, enabling long-duration experiments over a very broad range of forces spanning from 10 fN to 1 nN, with 1-10 milliseconds time and sub-nanometer spatial resolution. Their simplicity, robustness, and versatility have made magnetic tweezers a key technique within the field of single-molecule biophysics, being broadly applied to study the mechanical properties of, e.g., nucleic acids, genome processing molecular motors, protein folding, and nucleoprotein filaments. Furthermore, magnetic tweezers allow for high-throughput single-molecule measurements by tracking hundreds of biomolecules simultaneously both in real-time and at high spatiotemporal resolution. Magnetic tweezers naturally combine with surface-based fluorescence spectroscopy techniques, such as total internal reflection fluorescence microscopy, enabling correlative fluorescence and force/torque spectroscopy on biomolecules. This chapter presents an introduction to magnetic tweezers including a description of the hardware, the theory behind force calibration, its spatiotemporal resolution, combining it with other techniques, and a (non-exhaustive) overview of biological applications.
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Affiliation(s)
- David Dulin
- LaserLaB Amsterdam and Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.
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5
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Lin YY, Brouns T, Kolbeck PJ, Vanderlinden W, Lipfert J. High-yield ligation-free assembly of DNA constructs with nucleosome positioning sequence repeats for single-molecule manipulation assays. J Biol Chem 2023; 299:104874. [PMID: 37257819 PMCID: PMC10404619 DOI: 10.1016/j.jbc.2023.104874] [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: 03/27/2023] [Revised: 05/08/2023] [Accepted: 05/16/2023] [Indexed: 06/02/2023] Open
Abstract
Force and torque spectroscopy have provided unprecedented insights into the mechanical properties, conformational transitions, and dynamics of DNA and DNA-protein complexes, notably nucleosomes. Reliable single-molecule manipulation measurements require, however, specific and stable attachment chemistries to tether the molecules of interest. Here, we present a functionalization strategy for DNA that enables high-yield production of constructs for torsionally constrained and very stable attachment. The method is based on two subsequent PCRs: first ∼380 bp long DNA strands are generated that contain multiple labels, which are used as "megaprimers" in a second PCR to generate ∼kbp long double-stranded DNA constructs with multiple labels at the respective ends. To achieve high-force stability, we use dibenzocyclooctyne-based click chemistry for covalent attachment to the surface and biotin-streptavidin coupling to the bead. The resulting tethers are torsionally constrained and extremely stable under load, with an average lifetime of 70 ± 3 h at 45 pN. The high yield of the approach enables nucleosome reconstitution by salt dialysis on the functionalized DNA, and we demonstrate proof-of-concept measurements on nucleosome assembly statistics and inner turn unwrapping under force. We anticipate that our approach will facilitate a range of studies of DNA interactions and nucleoprotein complexes under forces and torques.
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Affiliation(s)
- Yi-Yun Lin
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Munich, Germany; Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands
| | - Tine Brouns
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Munich, Germany; Division of Molecular Imaging and Photonics, KU Leuven, Leuven, Belgium
| | - Pauline J Kolbeck
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Munich, Germany; Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands
| | - Willem Vanderlinden
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Munich, Germany; Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands.
| | - Jan Lipfert
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Munich, Germany; Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands.
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6
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Ruiz-Gutierrez N, Rieu M, Ouellet J, Allemand JF, Croquette V, Le Hir H. Novel approaches to study helicases using magnetic tweezers. Methods Enzymol 2022; 673:359-403. [PMID: 35965012 DOI: 10.1016/bs.mie.2022.03.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Helicases form a universal family of molecular motors that bind and translocate onto nucleic acids. They are involved in essentially every aspect of nucleic acid metabolism: from DNA replication to RNA decay, and thus ensure a large spectrum of functions in the cell, making their study essential. The development of micromanipulation techniques such as magnetic tweezers for the mechanistic study of these enzymes has provided new insights into their behavior and their regulation that were previously unrevealed by bulk assays. These experiments allowed very precise measures of their translocation speed, processivity and polarity. Here, we detail our newest technological advances in magnetic tweezers protocols for high-quality measurements and we describe the new procedures we developed to get a more profound understanding of helicase dynamics, such as their translocation in a force independent manner, their nucleic acid binding kinetics and their interaction with roadblocks.
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Affiliation(s)
- Nadia Ruiz-Gutierrez
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, PSL Research University, Paris, France
| | - Martin Rieu
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, PSL Research University, Paris, France; Laboratoire de Physique de L'Ecole Normale Supérieure de Paris, CNRS, ENS, Université PSL, Sorbonne Université, Université de Paris, Paris, France
| | | | - Jean-François Allemand
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, PSL Research University, Paris, France; Laboratoire de Physique de L'Ecole Normale Supérieure de Paris, CNRS, ENS, Université PSL, Sorbonne Université, Université de Paris, Paris, France
| | - Vincent Croquette
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, PSL Research University, Paris, France; Laboratoire de Physique de L'Ecole Normale Supérieure de Paris, CNRS, ENS, Université PSL, Sorbonne Université, Université de Paris, Paris, France; ESPCI Paris, Université PSL, Paris, France.
| | - Hervé Le Hir
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, PSL Research University, Paris, France.
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Henning-Knechtel A, Thirumalai D, Kirmizialtin S. Differences in ion-RNA binding modes due to charge density variations explain the stability of RNA in monovalent salts. SCIENCE ADVANCES 2022; 8:eabo1190. [PMID: 35857829 PMCID: PMC9299541 DOI: 10.1126/sciadv.abo1190] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The stability of RNA increases as the charge density of the alkali metal cations increases. The molecular mechanism for this phenomenon remains elusive. To fill this gap, we performed all-atom molecular dynamics pulling simulations of HIV-1 trans-activation response RNA. We first established that the free energy landscape obtained in the simulations is in excellent agreement with the single-molecule optical tweezer experiments. The origin of the stronger stability in sodium compared to potassium is found to be due to the differences in the charge density-related binding modes. The smaller hydrated sodium ion preferentially binds to the highly charged phosphates that have high surface area. In contrast, the larger potassium ions interact with the major grooves. As a result, more cations condense around phosphate groups in the case of sodium ions, leading to the reduction of electrostatic repulsion. Because the proposed mechanism is generic, we predict that the same conclusions are valid for divalent alkaline earth metal cations.
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Affiliation(s)
| | - D. Thirumalai
- Department of Chemistry, University of Texas, Austin, TX 78712, USA
- Corresponding author. (D.T.); (S.K.)
| | - Serdal Kirmizialtin
- Chemistry Program, Math and Sciences, New York University Abu Dhabi, Abu Dhabi, UAE
- Corresponding author. (D.T.); (S.K.)
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8
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Bera SC, America PPB, Maatsola S, Seifert M, Ostrofet E, Cnossen J, Spermann M, Papini FS, Depken M, Malinen AM, Dulin D. Quantitative parameters of bacterial RNA polymerase open-complex formation, stabilization and disruption on a consensus promoter. Nucleic Acids Res 2022; 50:7511-7528. [PMID: 35819191 PMCID: PMC9303404 DOI: 10.1093/nar/gkac560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 06/04/2022] [Accepted: 06/21/2022] [Indexed: 11/29/2022] Open
Abstract
Transcription initiation is the first step in gene expression, and is therefore strongly regulated in all domains of life. The RNA polymerase (RNAP) first associates with the initiation factor \documentclass[12pt]{minimal}
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}{}$\sigma$\end{document} to form a holoenzyme, which binds, bends and opens the promoter in a succession of reversible states. These states are critical for transcription regulation, but remain poorly understood. Here, we addressed the mechanism of open complex formation by monitoring its assembly/disassembly kinetics on individual consensus lacUV5 promoters using high-throughput single-molecule magnetic tweezers. We probed the key protein–DNA interactions governing the open-complex formation and dissociation pathway by modulating the dynamics at different concentrations of monovalent salts and varying temperatures. Consistent with ensemble studies, we observed that RNAP-promoter open (RPO) complex is a stable, slowly reversible state that is preceded by a kinetically significant open intermediate (RPI), from which the holoenzyme dissociates. A strong anion concentration and type dependence indicates that the RPO stabilization may involve sequence-independent interactions between the DNA and the holoenzyme, driven by a non-Coulombic effect consistent with the non-template DNA strand interacting with \documentclass[12pt]{minimal}
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}{}$\sigma$\end{document} and the RNAP \documentclass[12pt]{minimal}
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}{}$\beta$\end{document} subunit. The temperature dependence provides the energy scale of open-complex formation and further supports the existence of additional intermediates.
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Affiliation(s)
- Subhas C Bera
- Junior Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich Alexander University Erlangen-Nürnberg (FAU), Cauerstr. 3, 91058 Erlangen, Germany
| | - Pim P B America
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Santeri Maatsola
- Department of Life Technologies, University of Turku, Tykistökatu 6A, 6th floor, 20520 Turku, Finland
| | - Mona Seifert
- Junior Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich Alexander University Erlangen-Nürnberg (FAU), Cauerstr. 3, 91058 Erlangen, Germany
| | - Eugeniu Ostrofet
- Junior Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich Alexander University Erlangen-Nürnberg (FAU), Cauerstr. 3, 91058 Erlangen, Germany
| | - Jelmer Cnossen
- Delft Center for Systems and Control, Delft University of Technology, Delft, the Netherlands
| | - Monika Spermann
- Junior Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich Alexander University Erlangen-Nürnberg (FAU), Cauerstr. 3, 91058 Erlangen, Germany
| | - Flávia S Papini
- Junior Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich Alexander University Erlangen-Nürnberg (FAU), Cauerstr. 3, 91058 Erlangen, Germany
| | - Martin Depken
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Anssi M Malinen
- Department of Life Technologies, University of Turku, Tykistökatu 6A, 6th floor, 20520 Turku, Finland
| | - David Dulin
- Junior Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich Alexander University Erlangen-Nürnberg (FAU), Cauerstr. 3, 91058 Erlangen, Germany.,Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
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9
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Bell NAW, Molloy JE. Efficient golden gate assembly of DNA constructs for single molecule force spectroscopy and imaging. Nucleic Acids Res 2022; 50:e77. [PMID: 35489063 PMCID: PMC9303394 DOI: 10.1093/nar/gkac300] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 03/18/2022] [Accepted: 04/13/2022] [Indexed: 01/01/2023] Open
Abstract
Single-molecule techniques such as optical tweezers and fluorescence imaging are powerful tools for probing the biophysics of DNA and DNA-protein interactions. The application of these methods requires efficient approaches for creating designed DNA structures with labels for binding to a surface or microscopic beads. In this paper, we develop a simple and fast technique for making a diverse range of such DNA constructs by combining PCR amplicons and synthetic oligonucleotides using golden gate assembly rules. We demonstrate high yield fabrication of torsionally-constrained duplex DNA up to 10 kbp in length and a variety of DNA hairpin structures. We also show how tethering to a cross-linked antibody substrate significantly enhances measurement lifetime under high force. This rapid and adaptable fabrication method streamlines the assembly of DNA constructs for single molecule biophysics.
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10
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Electrochemical bioassay coupled to LAMP reaction for determination of high-risk HPV infection in crude lysates. Anal Chim Acta 2021; 1187:339145. [PMID: 34753575 DOI: 10.1016/j.aca.2021.339145] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 09/16/2021] [Accepted: 10/01/2021] [Indexed: 12/29/2022]
Abstract
Electrochemical (EC) detection of DNA biomarkers represents an interesting tool in molecular oncology due to its sensitivity, simplicity, low cost or rapid times of measurement. However, majority of EC assays, same as most optical-based techniques, require preceding DNA extraction step to remove other cellular components, making these assays more laborious and time-consuming. One option to circumvent this is to use LAMP (loop-mediated amplification), an isothermal amplification technique that can amplify DNA directly in crude lysates in a short time at a constant temperature. Here, we coupled the LAMP reaction with EC readout to detect DNA from the two most common oncogenic human papillomavirus (HPV) types that cause cervical cancer in women, i.e. HPV 16 and HPV 18, directly in crude lysates without a need for DNA extraction step. We show that in crude lysates, the LAMP reaction was superior to PCR, with very good selectivity on a panel of cancer cell lines and with high sensitivity, enabling detection of HPV DNA from as few as 10 cells. As a proof of principle, we applied the assay to nineteen clinical samples both from uninfected women and from women suffering from cervical precancerous lesions caused by HPV 16 or HPV 18 genotypes. Clinical samples were simply boiled for 5 min in homogenization buffer without DNA extraction step, and amplified with LAMP. We obtained excellent concordance of our assay with PCR, reaching 100% sensitivity for both genotypes, 81.82% specificity for HPV 16 and 94.12% specificity for HPV 18. Proposed assay could be a straightforward, simple, rapid and sensitive alternative for early diagnostics of precancerous cervical lesions.
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11
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Seifert M, Bera SC, van Nies P, Kirchdoerfer RN, Shannon A, Le TTN, Meng X, Xia H, Wood JM, Harris LD, Papini FS, Arnold JJ, Almo S, Grove TL, Shi PY, Xiang Y, Canard B, Depken M, Cameron CE, Dulin D. Inhibition of SARS-CoV-2 polymerase by nucleotide analogs from a single-molecule perspective. eLife 2021; 10:e70968. [PMID: 34617885 PMCID: PMC8497053 DOI: 10.7554/elife.70968] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 08/24/2021] [Indexed: 12/14/2022] Open
Abstract
The absence of 'shovel-ready' anti-coronavirus drugs during vaccine development has exceedingly worsened the SARS-CoV-2 pandemic. Furthermore, new vaccine-resistant variants and coronavirus outbreaks may occur in the near future, and we must be ready to face this possibility. However, efficient antiviral drugs are still lacking to this day, due to our poor understanding of the mode of incorporation and mechanism of action of nucleotides analogs that target the coronavirus polymerase to impair its essential activity. Here, we characterize the impact of remdesivir (RDV, the only FDA-approved anti-coronavirus drug) and other nucleotide analogs (NAs) on RNA synthesis by the coronavirus polymerase using a high-throughput, single-molecule, magnetic-tweezers platform. We reveal that the location of the modification in the ribose or in the base dictates the catalytic pathway(s) used for its incorporation. We show that RDV incorporation does not terminate viral RNA synthesis, but leads the polymerase into backtrack as far as 30 nt, which may appear as termination in traditional ensemble assays. SARS-CoV-2 is able to evade the endogenously synthesized product of the viperin antiviral protein, ddhCTP, though the polymerase incorporates this NA well. This experimental paradigm is essential to the discovery and development of therapeutics targeting viral polymerases.
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Affiliation(s)
- Mona Seifert
- Junior Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich-Alexander-University Erlangen-Nürnberg (FAU)ErlangenGermany
| | - Subhas C Bera
- Junior Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich-Alexander-University Erlangen-Nürnberg (FAU)ErlangenGermany
| | - Pauline van Nies
- Junior Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich-Alexander-University Erlangen-Nürnberg (FAU)ErlangenGermany
| | - Robert N Kirchdoerfer
- Department of Biochemistry and Institute of Molecular Virology, University of Wisconsin-MadisonMadisonUnited States
| | - Ashleigh Shannon
- Architecture et Fonction des Macromolécules Biologiques, CNRS and Aix-Marseille UniversitéMarseilleFrance
| | - Thi-Tuyet-Nhung Le
- Architecture et Fonction des Macromolécules Biologiques, CNRS and Aix-Marseille UniversitéMarseilleFrance
| | - Xiangzhi Meng
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center at San AntonioSan AntonioUnited States
| | - Hongjie Xia
- Department of Biochemistry and Molecular Biology, University of Texas Medical BranchGalvestonUnited States
| | - James M Wood
- The Ferrier Research Institute, Victoria University of WellingtonWellingtonNew Zealand
| | - Lawrence D Harris
- The Ferrier Research Institute, Victoria University of WellingtonWellingtonNew Zealand
| | - Flavia S Papini
- Junior Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich-Alexander-University Erlangen-Nürnberg (FAU)ErlangenGermany
| | - Jamie J Arnold
- Department of Microbiology and Immunology, University of North Carolina School of MedicineChapel HillUnited States
| | - Steven Almo
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, Institute for Protein InnovationBostonUnited States
| | - Tyler L Grove
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, Institute for Protein InnovationBostonUnited States
| | - Pei-Yong Shi
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Institute for Human Infections and Immunity, University of Texas Medical Branch, Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Sealy Center for Structural Biology & Molecular Biophysics, University of Texas Medical BranchGalvestonUnited States
| | - Yan Xiang
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center at San AntonioSan AntonioUnited States
| | - Bruno Canard
- Architecture et Fonction des Macromolécules Biologiques, CNRS and Aix-Marseille UniversitéMarseilleFrance
| | - Martin Depken
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of TechnologyDelftNetherlands
| | - Craig E Cameron
- Department of Microbiology and Immunology, University of North Carolina School of MedicineChapel HillUnited States
| | - David Dulin
- Junior Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich-Alexander-University Erlangen-Nürnberg (FAU)ErlangenGermany
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit AmsterdamAmsterdamNetherlands
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12
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The nucleotide addition cycle of the SARS-CoV-2 polymerase. Cell Rep 2021; 36:109650. [PMID: 34433083 PMCID: PMC8367775 DOI: 10.1016/j.celrep.2021.109650] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 07/10/2021] [Accepted: 08/11/2021] [Indexed: 12/29/2022] Open
Abstract
Coronaviruses have evolved elaborate multisubunit machines to replicate and transcribe their genomes. Central to these machines are the RNA-dependent RNA polymerase subunit (nsp12) and its intimately associated cofactors (nsp7 and nsp8). We use a high-throughput magnetic-tweezers approach to develop a mechanochemical description of this core polymerase. The core polymerase exists in at least three catalytically distinct conformations, one being kinetically consistent with incorporation of incorrect nucleotides. We provide evidence that the RNA-dependent RNA polymerase (RdRp) uses a thermal ratchet instead of a power stroke to transition from the pre- to post-translocated state. Ultra-stable magnetic tweezers enable the direct observation of coronavirus polymerase deep and long-lived backtracking that is strongly stimulated by secondary structures in the template. The framework we present here elucidates one of the most important structure-dynamics-function relationships in human health today and will form the grounds for understanding the regulation of this complex.
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13
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Lu Y, Bianco P. High-yield purification of exceptional-quality, single-molecule DNA substrates. J Biol Methods 2021; 8:e145. [PMID: 33889652 PMCID: PMC8054919 DOI: 10.14440/jbm.2021.350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 12/10/2020] [Accepted: 01/02/2021] [Indexed: 12/13/2022] Open
Abstract
Single-molecule studies involving DNA or RNA, require homogeneous preparations of nucleic acid substrates of exceptional quality. Over the past several years, a variety of methods have been published describing different purification methods but these are frustratingly inconsistent with variable yields even in the hands of experienced bench scientists. To address these issues, we present an optimized and straightforward, column-based approach that is reproducible and produces high yields of substrates or substrate components of exceptional quality. Central to the success of the method presented is the use of a non-porous anion exchange resin. In addition to the use of this resin, we encourage the optimization of each step in the construction of substrates. The fully optimized method produces high yields of a hairpin DNA substrate of exceptional quality. While this substrate is suitable for single-molecule, magnetic tweezer experiments, the described method is readily adaptable to the production of DNA substrates for the majority of single-molecule studies involving nucleic acids ranging in size from 70–15000 bp.
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Affiliation(s)
- Yue Lu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | - Piero Bianco
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA
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14
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Seifert M, Bera SC, van Nies P, Kirchdoerfer RN, Shannon A, Le TTN, Meng X, Xia H, Wood JM, Harris LD, Papini FS, Arnold JJ, Almo SC, Grove TL, Shi PY, Xiang Y, Canard B, Depken M, Cameron CE, Dulin D. Inhibition of SARS-CoV-2 polymerase by nucleotide analogs: a single molecule perspective. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021:2020.08.06.240325. [PMID: 33851161 PMCID: PMC8043451 DOI: 10.1101/2020.08.06.240325] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
The nucleotide analog Remdesivir (RDV) is the only FDA-approved antiviral therapy to treat infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The physical basis for efficient utilization of RDV by SARS-CoV-2 polymerase is unknown. Here, we characterize the impact of RDV and other nucleotide analogs on RNA synthesis by the polymerase using a high-throughput, single-molecule, magnetic-tweezers platform. The location of the modification in the ribose or in the base dictates the catalytic pathway(s) used for its incorporation. We reveal that RDV incorporation does not terminate viral RNA synthesis, but leads the polymerase into deep backtrack, which may appear as termination in traditional ensemble assays. SARS-CoV-2 is able to evade the endogenously synthesized product of the viperin antiviral protein, ddhCTP, though the polymerase incorporates this nucleotide analog well. This experimental paradigm is essential to the discovery and development of therapeutics targeting viral polymerases. TEASER We revise Remdesivir's mechanism of action and reveal SARS-CoV-2 ability to evade interferon-induced antiviral ddhCTP.
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Affiliation(s)
- Mona Seifert
- Junior Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Cauerstr. 3, 91058 Erlangen, Germany
| | - Subhas Chandra Bera
- Junior Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Cauerstr. 3, 91058 Erlangen, Germany
| | - Pauline van Nies
- Junior Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Cauerstr. 3, 91058 Erlangen, Germany
| | - Robert N. Kirchdoerfer
- Department of Biochemistry and Institute of Molecular Virology, University of Wisconsin-Madison, Madison, WI 53706
| | - Ashleigh Shannon
- Architecture et Fonction des Macromolécules Biologiques, CNRS and Aix-Marseille Université, UMR 7257, Polytech Case 925, 13009 Marseille, France
| | - Thi-Tuyet-Nhung Le
- Architecture et Fonction des Macromolécules Biologiques, CNRS and Aix-Marseille Université, UMR 7257, Polytech Case 925, 13009 Marseille, France
| | - Xiangzhi Meng
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Hongjie Xia
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - James M. Wood
- The Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand
| | - Lawrence D. Harris
- The Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand
| | - Flávia S. Papini
- Junior Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Cauerstr. 3, 91058 Erlangen, Germany
| | - Jamie J. Arnold
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, NC 27599 USA
| | - Steven C. Almo
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, USA Institute for Protein Innovation, Boston, MA, USA
| | - Tyler L. Grove
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, USA Institute for Protein Innovation, Boston, MA, USA
| | - Pei-Yong Shi
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA; Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, TX 77555, USA; Sealy Center for Structural Biology & Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Yan Xiang
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Bruno Canard
- Architecture et Fonction des Macromolécules Biologiques, CNRS and Aix-Marseille Université, UMR 7257, Polytech Case 925, 13009 Marseille, France
| | - Martin Depken
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Craig E. Cameron
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, NC 27599 USA
| | - David Dulin
- Junior Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Cauerstr. 3, 91058 Erlangen, Germany
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
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