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Stransky F, Kostrz D, Follenfant M, Pomplun S, Meyners C, Strick T, Hausch F, Gosse C. Use of DNA forceps to measure receptor-ligand dissociation equilibrium constants in a single-molecule competition assay. Methods Enzymol 2024; 694:51-82. [PMID: 38492958 DOI: 10.1016/bs.mie.2024.01.010] [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: 03/18/2024]
Abstract
The ability of biophysicists to decipher the behavior of individual biomolecules has steadily improved over the past thirty years. However, it still remains unclear how an ensemble of data acquired at the single-molecule level compares with the data acquired on an ensemble of the same molecules. We here propose an assay to tackle this question in the context of dissociation equilibrium constant measurements. A sensor is built by engrafting a receptor and a ligand onto a flexible dsDNA scaffold and mounting this assembly on magnetic tweezers. This way, looking at the position of the magnetic bead enables one to determine in real-time if the two molecular partners are associated or not. Next, to quantify the affinity of the scrutinized single-receptor for a given competitor, various amounts of the latter molecule are introduced in solution and the equilibrium response of the sensor is monitored throughout the titration protocol. Proofs of concept are established for the binding of three rapamycin analogs to the FKBP12 cis-trans prolyl isomerase. For each of these drugs the mean affinity constant obtained on a ten of individual receptors agrees with the one previously determined in a bulk assay. Furthermore, experimental contingencies are sufficient to explain the dispersion observed over the single-molecule values.
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Affiliation(s)
- François Stransky
- Institut de Biologie de l'Ecole Normale Supérieure, ENS, CNRS, INSERM, PSL Research University, Paris, France
| | - Dorota Kostrz
- Institut de Biologie de l'Ecole Normale Supérieure, ENS, CNRS, INSERM, PSL Research University, Paris, France
| | - Maryne Follenfant
- Institut de Biologie de l'Ecole Normale Supérieure, ENS, CNRS, INSERM, PSL Research University, Paris, France
| | - Sebastian Pomplun
- Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Christian Meyners
- Department of Chemistry and Biochemistry, Technical University Darmstadt, Darmstadt, Germany
| | - Terence Strick
- Institut de Biologie de l'Ecole Normale Supérieure, ENS, CNRS, INSERM, PSL Research University, Paris, France
| | - Felix Hausch
- Department of Chemistry and Biochemistry, Technical University Darmstadt, Darmstadt, Germany; Centre for Synthetic Biology, Technical University Darmstadt, Darmstadt, Germany
| | - Charlie Gosse
- Institut de Biologie de l'Ecole Normale Supérieure, ENS, CNRS, INSERM, PSL Research University, Paris, France.
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Croquette V, Orero JV, Rieu M, Allemand JF. Magnetic tweezers principles and promises. Methods Enzymol 2024; 694:1-49. [PMID: 38492947 DOI: 10.1016/bs.mie.2024.01.026] [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: 03/18/2024]
Abstract
Magnetic tweezers have become popular with the outbreak of single molecule micromanipulation: catching a single molecule of DNA, RNA or a single protein and applying mechanical constrains using micron-size magnetic beads and magnets turn out to be easy. Various factors have made this possible: the fact that manufacturers have been preparing these beads to catch various biological entities-the ease of use provided by magnets which apply a force or a torque at a distance thus inside a flow cell-some chance: since the forces so generated are in the right range to stretch a single molecule. This is a little less true for torque. Finally, one feature which also appears very important is the simplicity of their calibration using Brownian motion. Here we start by describing magnetic tweezers used routinely in our laboratory where we have tried to develop a device as simple as possible so that the experimentalist can really focus on the biological aspect of the biomolecules that he/she is interested in. We discuss the implications of the various components and their important features. Next, we summarize what is easy to achieve and what is less easy. Then we refer to contributions by other groups who have brought valuable insights to improve magnetic tweezers.
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Affiliation(s)
- Vincent Croquette
- Laboratoire de Physique de l'École normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France; ESPCI Paris, Université PSL, Paris, France.
| | - Jessica Valle Orero
- Laboratoire de Physique de l'École normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France; The American University of Paris, Paris, France
| | - Martin Rieu
- Department of Physics, New Biochemistry Building, University of Oxford, South Parks Road, Oxford, United Kingdom
| | - Jean-François Allemand
- Laboratoire de Physique de l'École normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
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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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Ding F, Cocco S, Raj S, Manosas M, Nguyen T, Spiering M, Bensimon D, Allemand JF, Croquette V. Displacement and dissociation of oligonucleotides during DNA hairpin closure under strain. Nucleic Acids Res 2022; 50:12082-12093. [PMID: 36478056 PMCID: PMC9757040 DOI: 10.1093/nar/gkac1113] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 10/19/2022] [Accepted: 11/07/2022] [Indexed: 12/12/2022] Open
Abstract
The hybridization kinetic of an oligonucleotide to its template is a fundamental step in many biological processes such as replication arrest, CRISPR recognition, DNA sequencing, DNA origami, etc. Although single kinetic descriptions exist for special cases of this problem, there are no simple general prediction schemes. In this work, we have measured experimentally, with no fluorescent labelling, the displacement of an oligonucleotide from its substrate in two situations: one corresponding to oligonucleotide binding/unbinding on ssDNA and one in which the oligonucleotide is displaced by the refolding of a dsDNA fork. In this second situation, the fork is expelling the oligonucleotide thus significantly reducing its residence time. To account for our data in these two situations, we have constructed a mathematical model, based on the known nearest neighbour dinucleotide free energies, and provided a good estimate of the residence times of different oligonucleotides (DNA, RNA, LNA) of various lengths in different experimental conditions (force, temperature, buffer conditions, presence of mismatches, etc.). This study provides a foundation for the dynamics of oligonucleotide displacement, a process of importance in numerous biological and bioengineering contexts.
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Affiliation(s)
- Fangyuan Ding
- Department of Biomedical Engineering, University of California, Irvine, CA 92617, USA
- Center for Complex Biological Systems, University of California, Irvine, CA 92697, USA
- Center for Synthetic Biology, Chao Family Comprehensive Cancer Center, Department of Developmental and Cell Biology, and Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697, USA
| | - Simona Cocco
- Laboratoire de Physique de l’Ecole normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
| | - Saurabh Raj
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, 110016, India
| | - Maria Manosas
- Small Biosystems Lab, Departament de Física de la Matèria Condensada, Facultat de Física, Universitat de Barcelona, Carrer de Martí i Franquès, 1, 08028 Barcelona, Spain
- Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, 08028 Barcelona, Spain
| | - Thao Thi Thu Nguyen
- Center for Complex Biological Systems, University of California, Irvine, CA 92697, USA
| | - Michelle M Spiering
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - David Bensimon
- Laboratoire de Physique de l’Ecole normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
- Institut de Biologie de l’École Normale Supérieure (IBENS), CNRS, Inserm, École Normale Supérieure, PSL Research University, F-75005, Paris, France
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Jean-François Allemand
- Laboratoire de Physique de l’Ecole normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
- Institut de Biologie de l’École Normale Supérieure (IBENS), CNRS, Inserm, École Normale Supérieure, PSL Research University, F-75005, Paris, France
| | - Vincent Croquette
- Laboratoire de Physique de l’Ecole normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
- Institut de Biologie de l’École Normale Supérieure (IBENS), CNRS, Inserm, École Normale Supérieure, PSL Research University, F-75005, Paris, France
- ESPCI Paris, Université PSL, Paris, France
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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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Li J, Ma J, Kumar V, Fu H, Xu C, Wang S, Jia Q, Fan Q, Xi X, Li M, Liu H, Lu Y. Identification of flexible Pif1-DNA interactions and their impacts on enzymatic activities. Nucleic Acids Res 2022; 50:7002-7012. [PMID: 35748877 PMCID: PMC9262596 DOI: 10.1093/nar/gkac529] [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: 12/12/2021] [Revised: 05/31/2022] [Accepted: 06/07/2022] [Indexed: 12/24/2022] Open
Abstract
Flexible regions in biomolecular complexes, although crucial to understanding structure-function relationships, are often unclear in high-resolution crystal structures. In this study, we showed that single-molecule techniques, in combination with computational modeling, can characterize dynamic conformations not resolved by high-resolution structure determination methods. Taking two Pif1 helicases (ScPif1 and BsPif1) as model systems, we found that, besides a few tightly bound nucleotides, adjacent solvent-exposed nucleotides interact dynamically with the helicase surfaces. The whole nucleotide segment possessed curved conformations and covered the two RecA-like domains of the helicases, which are essential for the inch-worm mechanism. The synergetic approach reveals that the interactions between the exposed nucleotides and the helicases could be reduced by large stretching forces or electrostatically shielded with high-concentration salt, subsequently resulting in reduced translocation rates of the helicases. The dynamic interactions between the exposed nucleotides and the helicases underlay the force- and salt-dependences of their enzymatic activities. The present single-molecule based approach complements high-resolution structural methods in deciphering the molecular mechanisms of the helicases.
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Affiliation(s)
| | | | | | - Hang Fu
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325011, China,School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chunhua Xu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shuang Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Qi Jia
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China,Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Qinkai Fan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China,School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xuguang Xi
- Laboratoire de Biologie et Pharmacologie Appliquée (LBPA), UMR8113 CNRS, ENS Paris-Saclay, Université Paris-Saclay, Gif-sur-Yvette F-91190, France
| | - Ming Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China,Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China,School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haiguang Liu
- Correspondence may also be addressed to Haiguang Liu. Tel: +86 10 56981816;
| | - Ying Lu
- To whom correspondence should be addressed. Tel: +86 10 82648122;
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