1
|
Lokanathan Balaji S, De Bragança S, Balaguer-Pérez F, Northall S, Wilkinson OJ, Aicart-Ramos C, Seetaloo N, Sobott F, Moreno-Herrero F, Dillingham MS. DNA binding and bridging by human CtIP in the healthy and diseased states. Nucleic Acids Res 2024; 52:8303-8319. [PMID: 38922686 DOI: 10.1093/nar/gkae538] [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: 01/10/2024] [Revised: 06/05/2024] [Accepted: 06/13/2024] [Indexed: 06/28/2024] Open
Abstract
The human DNA repair factor CtIP helps to initiate the resection of double-stranded DNA breaks for repair by homologous recombination, in part through its ability to bind and bridge DNA molecules. However, CtIP is a natively disordered protein that bears no apparent similarity to other DNA-binding proteins and so the structural basis for these activities remains unclear. In this work, we have used bulk DNA binding, single molecule tracking, and DNA bridging assays to study wild-type and variant CtIP proteins to better define the DNA binding domains and the effects of mutations associated with inherited human disease. Our work identifies a monomeric DNA-binding domain in the C-terminal region of CtIP. CtIP binds non-specifically to DNA and can diffuse over thousands of nucleotides. CtIP-mediated bridging of distant DNA segments is observed in single-molecule magnetic tweezers experiments. However, we show that binding alone is insufficient for DNA bridging, which also requires tetramerization via the N-terminal domain. Variant CtIP proteins associated with Seckel and Jawad syndromes display impaired DNA binding and bridging activities. The significance of these findings in the context of facilitating DNA break repair is discussed.
Collapse
Affiliation(s)
- Shreya Lokanathan Balaji
- DNA:Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Sara De Bragança
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049, Spain
| | - Francisco Balaguer-Pérez
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049, Spain
| | - Sarah Northall
- DNA:Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Oliver John Wilkinson
- DNA:Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Clara Aicart-Ramos
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049, Spain
| | - Neeleema Seetaloo
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Frank Sobott
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Fernando Moreno-Herrero
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049, Spain
| | - Mark Simon Dillingham
- DNA:Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| |
Collapse
|
2
|
Shepherd JW, Guilbaud S, Zhou Z, Howard JAL, Burman M, Schaefer C, Kerrigan A, Steele-King C, Noy A, Leake MC. Correlating fluorescence microscopy, optical and magnetic tweezers to study single chiral biopolymers such as DNA. Nat Commun 2024; 15:2748. [PMID: 38553446 PMCID: PMC10980717 DOI: 10.1038/s41467-024-47126-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 03/21/2024] [Indexed: 04/02/2024] Open
Abstract
Biopolymer topology is critical for determining interactions inside cell environments, exemplified by DNA where its response to mechanical perturbation is as important as biochemical properties to its cellular roles. The dynamic structures of chiral biopolymers exhibit complex dependence with extension and torsion, however the physical mechanisms underpinning the emergence of structural motifs upon physiological twisting and stretching are poorly understood due to technological limitations in correlating force, torque and spatial localization information. We present COMBI-Tweez (Combined Optical and Magnetic BIomolecule TWEEZers), a transformative tool that overcomes these challenges by integrating optical trapping, time-resolved electromagnetic tweezers, and fluorescence microscopy, demonstrated on single DNA molecules, that can controllably form and visualise higher order structural motifs including plectonemes. This technology combined with cutting-edge MD simulations provides quantitative insight into complex dynamic structures relevant to DNA cellular processes and can be adapted to study a range of filamentous biopolymers.
Collapse
Affiliation(s)
- Jack W Shepherd
- School of Physics, Engineering and Technology, University of York, York, YO10 5DD, England
- Department of Biology, University of York, York, YO10 5DD, England
| | - Sebastien Guilbaud
- School of Physics, Engineering and Technology, University of York, York, YO10 5DD, England
| | - Zhaokun Zhou
- Guangdong Provincial Key Lab of Robotics and Intelligent System, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Jamieson A L Howard
- School of Physics, Engineering and Technology, University of York, York, YO10 5DD, England
| | - Matthew Burman
- School of Physics, Engineering and Technology, University of York, York, YO10 5DD, England
| | - Charley Schaefer
- School of Physics, Engineering and Technology, University of York, York, YO10 5DD, England
| | - Adam Kerrigan
- The York-JEOL Nanocentre, University of York, York, YO10 5BR, England
| | - Clare Steele-King
- Bioscience Technology Facility, University of York, York, YO10 5DD, England
| | - Agnes Noy
- School of Physics, Engineering and Technology, University of York, York, YO10 5DD, England
| | - Mark C Leake
- School of Physics, Engineering and Technology, University of York, York, YO10 5DD, England.
- Department of Biology, University of York, York, YO10 5DD, England.
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
Mierke CT. Magnetic tweezers in cell mechanics. Methods Enzymol 2024; 694:321-354. [PMID: 38492957 DOI: 10.1016/bs.mie.2023.12.007] [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 chapter provides an overview of the applications of magnetic tweezers in living cells. It discusses the advantages and disadvantages of magnetic tweezers technology with a focus on individual magnetic tweezers configurations, such as electromagnetic tweezers. Solutions to the disadvantages identified are also outlined. The specific role of magnetic tweezers in the field of mechanobiology, such as mechanosensitivity, mechano-allostery and mechanotransduction are also emphasized. The specific usage of magnetic tweezers in mechanically probing cells via specific cell surface receptors, such as mechanosensitive channels is discussed and why mechanical probing has revealed the opening and closing of the channels. Finally, the future direction of magnetic tweezers is presented.
Collapse
Affiliation(s)
- Claudia Tanja Mierke
- Faculty of Physics and Earth System Sciences, Peter Debye Institute for Soft Matter Physics, Biological Physics Division, Leipzig University, Leipzig, Germany.
| |
Collapse
|
5
|
Yang H, Shi X. The Free Energy of Nucleosomal DNA Based on the Landau Model and Topology. Biomolecules 2023; 13:1686. [PMID: 38136559 PMCID: PMC10741420 DOI: 10.3390/biom13121686] [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: 09/10/2023] [Revised: 10/30/2023] [Accepted: 11/09/2023] [Indexed: 12/24/2023] Open
Abstract
The free energy of nucleosomal DNA plays a key role in the formation of nucleosomes in eukaryotes. Some work on the free energy of nucleosomal DNA have been carried out in experiments. However, the relationships between the free energy of nucleosomal DNA and its conformation, especially its topology, remain unclear in theory. By combining the Landau theory, the Hopfion model and experimental data, we find that the free energy of nucleosomal DNA is at the lower level. With the help of the energy minimum principle, we conclude that nucleosomal DNA stays in a stable state. Moreover, we discover that small perturbations on nucleosomal DNA have little effect on its free energy. This implies that nucleosomal DNA has a certain redundancy in order to stay stable. This explains why nucleosomal DNA will not change significantly due to small perturbations.
Collapse
Affiliation(s)
| | - Xuguang Shi
- College of Science, Beijing Forestry University, Beijing 100083, China;
| |
Collapse
|
6
|
Zhou Y, Tang Q, Zhao X, Zeng X, Chong C, Yan J. A novel design for magnetic tweezers with wide-range temperature control. Biophys J 2023; 122:3860-3868. [PMID: 37563833 PMCID: PMC10560670 DOI: 10.1016/j.bpj.2023.08.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 06/19/2023] [Accepted: 08/07/2023] [Indexed: 08/12/2023] Open
Abstract
Single-molecule manipulation technologies have proven to be powerful tools for studying the molecular mechanisms and physical principles underlying many essential biological processes. However, achieving wide-range temperature control has been challenging due to thermal drift that undermines the stability of the instrument. This limitation has made it difficult to study biomolecules from thermophiles at their physiologically relevant temperatures and has also hindered the convenient measurement of temperature-sensitive biomolecular interactions and the fundamental thermodynamic properties of biomolecules. In this work, we present a novel design of magnetic tweezers that uses a reflective coverslip and dry objective lens to insulate the heat conductance between the sample and the objective lens, enabling stable temperature changes from ambient up to 70°C during experiments without significant thermal drift of the instrument. The performance of the technology is demonstrated through the quantification of the free energy change of a DNA hairpin over a temperature range of 22°C-72°C, from which the entropy and enthalpy changes are determined.
Collapse
Affiliation(s)
- Yu Zhou
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | - Qingnan Tang
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Xiaodan Zhao
- Department of Physics, National University of Singapore, Singapore, Singapore; Centre for Bioimaging Sciences, National University of Singapore, Singapore, Singapore
| | - Xiangjun Zeng
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Clarence Chong
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Jie Yan
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore; Department of Physics, National University of Singapore, Singapore, Singapore; Centre for Bioimaging Sciences, National University of Singapore, Singapore, Singapore; Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou, China.
| |
Collapse
|
7
|
Yang ZY, Jiang WY, Ran SY. Reductant-dependent DNA-templated silver nanoparticle formation kinetics. Phys Chem Chem Phys 2023; 25:23197-23206. [PMID: 37605826 DOI: 10.1039/d3cp02623j] [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: 08/23/2023]
Abstract
DNA molecules have been demonstrated to be good templates for producing silver nanoparticles (AgNPs), with the advantages of well-controlled sizes, shapes, and properties. Revealing the formation kinetics of DNA-templated AgNPs is crucial for their efficient synthesis. Herein, using magnetic tweezers, we studied the reduction kinetics of the Ag+-DNA structure and the subsequent nucleation kinetics by adding NaBH4, L-ascorbic acid, and sodium citrate solutions. At [Ag+] = 0.01 mM, the addition of NaBH4 solution with the same concentration resulted in the restoration of DNA. In contrast, by increasing the [NaBH4]/[Ag+] ratio (r) to 10 and 100, the DNA extension initially decreased rapidly and then increased, indicating nucleation-dissolution kinetics. With AgNO3 solutions of higher concentrations (0.1 mM and 1 mM), direct particle nucleation and growth kinetics were observed by adding a tenfold (r = 10) or a hundredfold (r = 100) amount of NaBH4, which were evidenced by a significant reduction in DNA extension. The reductant dependence of the kinetics was further investigated. Addition of L-ascorbic acid to the DNA-Ag+ solution yielded an increase-decrease kinetics that was different from that caused by NaBH4, suggesting that nucleation was not initially favored due to the lack of sufficient Ag atoms; while sodium citrate showed a weak nucleation-promoting ability to form AgNPs. We discussed the findings within the framework of classical nucleation theory, in which the supersaturation of the Ag atom is strongly influenced by multiple factors (including the reducing ability of the reductant), resulting in different kinetics.
Collapse
Affiliation(s)
- Zi-Yang Yang
- Department of Physics, Wenzhou University, Wenzhou 325035, China.
| | - Wen-Yan Jiang
- Department of Physics, Wenzhou University, Wenzhou 325035, China.
| | - Shi-Yong Ran
- Department of Physics, Wenzhou University, Wenzhou 325035, China.
| |
Collapse
|
8
|
Lostao A, Lim K, Pallarés MC, Ptak A, Marcuello C. Recent advances in sensing the inter-biomolecular interactions at the nanoscale - A comprehensive review of AFM-based force spectroscopy. Int J Biol Macromol 2023; 238:124089. [PMID: 36948336 DOI: 10.1016/j.ijbiomac.2023.124089] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/13/2023] [Accepted: 03/15/2023] [Indexed: 03/24/2023]
Abstract
Biomolecular interactions underpin most processes inside the cell. Hence, a precise and quantitative understanding of molecular association and dissociation events is crucial, not only from a fundamental perspective, but also for the rational design of biomolecular platforms for state-of-the-art biomedical and industrial applications. In this context, atomic force microscopy (AFM) appears as an invaluable experimental technique, allowing the measurement of the mechanical strength of biomolecular complexes to provide a quantitative characterization of their interaction properties from a single molecule perspective. In the present review, the most recent methodological advances in this field are presented with special focus on bioconjugation, immobilization and AFM tip functionalization, dynamic force spectroscopy measurements, molecular recognition imaging and theoretical modeling. We expect this work to significantly aid in grasping the principles of AFM-based force spectroscopy (AFM-FS) technique and provide the necessary tools to acquaint the type of data that can be achieved from this type of experiments. Furthermore, a critical assessment is done with other nanotechnology techniques to better visualize the future prospects of AFM-FS.
Collapse
Affiliation(s)
- Anabel Lostao
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza 50009, Spain; Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, Zaragoza 50018, Spain; Fundación ARAID, Aragón, Spain.
| | - KeeSiang Lim
- WPI-Nano Life Science Institute, Kanazawa University, Ishikawa 920-1192, Japan
| | - María Carmen Pallarés
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza 50009, Spain; Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, Zaragoza 50018, Spain
| | - Arkadiusz Ptak
- Institute of Physics, Faculty of Materials Engineering and Technical Physics, Poznan University of Technology, Poznan 60-925, Poland
| | - Carlos Marcuello
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza 50009, Spain; Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, Zaragoza 50018, Spain.
| |
Collapse
|
9
|
De Bragança S, Aicart-Ramos C, Arribas-Bosacoma R, Rivera-Calzada A, Unfried JP, Prats-Mari L, Marin-Baquero M, Fortes P, Llorca O, Moreno-Herrero F. APLF and long non-coding RNA NIHCOLE promote stable DNA synapsis in non-homologous end joining. Cell Rep 2023; 42:111917. [PMID: 36640344 DOI: 10.1016/j.celrep.2022.111917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 10/26/2022] [Accepted: 12/13/2022] [Indexed: 01/01/2023] Open
Abstract
The synapsis of DNA ends is a critical step for the repair of double-strand breaks by non-homologous end joining (NHEJ). This is performed by a multicomponent protein complex assembled around Ku70-Ku80 heterodimers and regulated by accessory factors, including long non-coding RNAs, through poorly understood mechanisms. Here, we use magnetic tweezers to investigate the contributions of core NHEJ proteins and APLF and lncRNA NIHCOLE to DNA synapsis. APLF stabilizes DNA end bridging and, together with Ku70-Ku80, establishes a minimal complex that supports DNA synapsis for several minutes under piconewton forces. We find the C-terminal acidic region of APLF to be critical for bridging. NIHCOLE increases the dwell time of the synapses by Ku70-Ku80 and APLF. This effect is further enhanced by a small and structured RNA domain within NIHCOLE. We propose a model where Ku70-Ku80 can simultaneously bind DNA, APLF, and structured RNAs to promote the stable joining of DNA ends.
Collapse
Affiliation(s)
- Sara De Bragança
- Department of Macromolecular Structures, Centro Nacional de Biotecnología (CNB), CSIC, Madrid, Spain
| | - Clara Aicart-Ramos
- Department of Macromolecular Structures, Centro Nacional de Biotecnología (CNB), CSIC, Madrid, Spain
| | - Raquel Arribas-Bosacoma
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Angel Rivera-Calzada
- Structural Biology Programme, Spanish National Cancer Research Center (CNIO), Madrid, Spain
| | - Juan Pablo Unfried
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel; Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of Navarra (UNAV), Pamplona, Spain
| | - Laura Prats-Mari
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of Navarra (UNAV), Pamplona, Spain
| | - Mikel Marin-Baquero
- Department of Macromolecular Structures, Centro Nacional de Biotecnología (CNB), CSIC, Madrid, Spain
| | - Puri Fortes
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of Navarra (UNAV), Pamplona, Spain; Navarra Institute for Health Research (IdiSNA), Pamplona, Spain; Liver and Digestive Diseases Networking Biomedical Research Centre (CIBERehd), Spanish Network for Advanced Therapies (TERAV ISCIII), Madrid, Spain
| | - Oscar Llorca
- Structural Biology Programme, Spanish National Cancer Research Center (CNIO), Madrid, Spain.
| | - Fernando Moreno-Herrero
- Department of Macromolecular Structures, Centro Nacional de Biotecnología (CNB), CSIC, Madrid, Spain.
| |
Collapse
|
10
|
Xiong Q, Lee OS, Mirkin CA, Schatz G. Ethanol-Induced Condensation and Decondensation in DNA-Linked Nanoparticles: A Nucleosome-like Model for the Condensed State. J Am Chem Soc 2023; 145:706-716. [PMID: 36573457 DOI: 10.1021/jacs.2c11834] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Inspired by the conventional use of ethanol to induce DNA precipitation, ethanol condensation has been applied as a routine method to dynamically tune "bond" lengths (i.e., the surface-to-surface distances between adjacent nanoparticles that are linked by DNA) and thermal stabilities of colloidal crystals involving DNA-linked nanoparticles. However, the underlying mechanism of how the DNA bond that links gold nanoparticles changes in this class of colloidal crystals in response to ethanol remains unclear. Here, we conducted a series of all-atom molecular dynamic (MD) simulations to explore the free energy landscape for DNA condensation and decondensation. Our simulations confirm that DNA condensation is energetically much more favorable under 80% ethanol conditions than in pure water, as a result of ethanol's role in enhancing electrostatic interactions between oppositely charged species. Moreover, the condensed DNA adopts B-form in pure water and A-form in 80% ethanol, which indicates that the higher-order transition does not affect DNA's conformational preferences. We further propose a nucleosome-like supercoiled model for the DNA condensed state, and we show that the DNA end-to-end distance derived from this model matches the experimentally measured DNA bond length of about 3 nm in the fully condensed state for DNA where the measured length is 16 nm in water. Overall, this study provides an atomistic understanding of the mechanism underlying ethanol-induced condensation and water-induced decondensation, while our proposed nucleosome-like model allows the design of new strategies for interpreting experimental studies of DNA condensation.
Collapse
Affiliation(s)
- Qinsi Xiong
- Department of Chemistry, Northwestern University, Evanston, Illinois60208-3113, United States
| | - One-Sun Lee
- Department of Chemistry, Northwestern University, Evanston, Illinois60208-3113, United States
| | - Chad A Mirkin
- Department of Chemistry, Northwestern University, Evanston, Illinois60208-3113, United States.,Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois60208, United States.,International Institute for Nanotechnology, Northwestern University, Evanston, Illinois60208, United States
| | - George Schatz
- Department of Chemistry, Northwestern University, Evanston, Illinois60208-3113, United States
| |
Collapse
|
11
|
Coloma J, Gonzalez-Rodriguez N, Balaguer FA, Gmurczyk K, Aicart-Ramos C, Nuero ÓM, Luque-Ortega JR, Calugaru K, Lue NF, Moreno-Herrero F, Llorca O. Molecular architecture and oligomerization of Candida glabrata Cdc13 underpin its telomeric DNA-binding and unfolding activity. Nucleic Acids Res 2023; 51:668-686. [PMID: 36629261 PMCID: PMC9881146 DOI: 10.1093/nar/gkac1261] [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: 05/27/2022] [Revised: 12/14/2022] [Accepted: 12/19/2022] [Indexed: 01/12/2023] Open
Abstract
The CST complex is a key player in telomere replication and stability, which in yeast comprises Cdc13, Stn1 and Ten1. While Stn1 and Ten1 are very well conserved across species, Cdc13 does not resemble its mammalian counterpart CTC1 either in sequence or domain organization, and Cdc13 but not CTC1 displays functions independently of the rest of CST. Whereas the structures of human CTC1 and CST have been determined, the molecular organization of Cdc13 remains poorly understood. Here, we dissect the molecular architecture of Candida glabrata Cdc13 and show how it regulates binding to telomeric sequences. Cdc13 forms dimers through the interaction between OB-fold 2 (OB2) domains. Dimerization stimulates binding of OB3 to telomeric sequences, resulting in the unfolding of ssDNA secondary structure. Once bound to DNA, Cdc13 prevents the refolding of ssDNA by mechanisms involving all domains. OB1 also oligomerizes, inducing higher-order complexes of Cdc13 in vitro. OB1 truncation disrupts these complexes, affects ssDNA unfolding and reduces telomere length in C. glabrata. Together, our results reveal the molecular organization of C. glabrata Cdc13 and how this regulates the binding and the structure of DNA, and suggest that yeast species evolved distinct architectures of Cdc13 that share some common principles.
Collapse
Affiliation(s)
- Javier Coloma
- Correspondence may also be addressed to Javier Coloma. Tel: +34 91 732 8000 (Ext 3033);
| | | | - Francisco A Balaguer
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Karolina Gmurczyk
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Clara Aicart-Ramos
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Óscar M Nuero
- Molecular Interactions Facility, Centro de Investigaciones Biológicas Margarita Salas (CSIC), Madrid, Spain
| | - Juan Román Luque-Ortega
- Molecular Interactions Facility, Centro de Investigaciones Biológicas Margarita Salas (CSIC), Madrid, Spain
| | - Kimberly Calugaru
- Department of Microbiology and Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, New York, NY, USA
| | - Neal F Lue
- Department of Microbiology and Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, New York, NY, USA
| | | | - Oscar Llorca
- To whom correspondence should be addressed. Tel: +34 91 732 8000 (Ext 3000);
| |
Collapse
|
12
|
Akbari E, Shahhosseini M, Robbins A, Poirier MG, Song JW, Castro CE. Low cost and massively parallel force spectroscopy with fluid loading on a chip. Nat Commun 2022; 13:6800. [PMID: 36357383 PMCID: PMC9649742 DOI: 10.1038/s41467-022-34212-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 10/18/2022] [Indexed: 11/12/2022] Open
Abstract
Current approaches for single molecule force spectroscopy are typically constrained by low throughput and high instrumentation cost. Herein, a low-cost, high throughput technique is demonstrated using microfluidics for multiplexed mechanical manipulation of up to ~4000 individual molecules via molecular fluid loading on-a-chip (FLO-Chip). The FLO-Chip consists of serially connected microchannels with varying width, allowing for simultaneous testing at multiple loading rates. Molecular force measurements are demonstrated by dissociating Biotin-Streptavidin and Digoxigenin-AntiDigoxigenin interactions along with unzipping of double stranded DNA of varying sequence under different dynamic loading rates and solution conditions. Rupture force results under varying loading rates and solution conditions are in good agreement with prior studies, verifying a versatile approach for single molecule biophysics and molecular mechanobiology. FLO-Chip enables straightforward, rapid, low-cost, and portable mechanical testing of single molecules that can be implemented on a wide range of microscopes to broaden access and may enable new applications of molecular force spectroscopy.
Collapse
Affiliation(s)
- Ehsan Akbari
- Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH, 43210, USA
- Department of Physics, The Ohio State University, Columbus, OH, 43210, USA
| | - Melika Shahhosseini
- Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Ariel Robbins
- Department of Physics, The Ohio State University, Columbus, OH, 43210, USA
- Biophysics Graduate Program, The Ohio State University, Columbus, OH, 43210, USA
| | - Michael G Poirier
- Department of Physics, The Ohio State University, Columbus, OH, 43210, USA
- Biophysics Graduate Program, The Ohio State University, Columbus, OH, 43210, USA
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, USA
| | - Jonathan W Song
- Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH, 43210, USA
- Comprehensive Cancer Center, The Ohio State University, Columbus, OH, 43210, USA
| | - Carlos E Castro
- Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH, 43210, USA.
- Biophysics Graduate Program, The Ohio State University, Columbus, OH, 43210, USA.
| |
Collapse
|
13
|
Huisjes NM, Retzer TM, Scherr MJ, Agarwal R, Rajappa L, Safaric B, Minnen A, Duderstadt KE. Mars, a molecule archive suite for reproducible analysis and reporting of single-molecule properties from bioimages. eLife 2022; 11:e75899. [PMID: 36098381 PMCID: PMC9470159 DOI: 10.7554/elife.75899] [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: 11/26/2021] [Accepted: 08/19/2022] [Indexed: 11/16/2022] Open
Abstract
The rapid development of new imaging approaches is generating larger and more complex datasets, revealing the time evolution of individual cells and biomolecules. Single-molecule techniques, in particular, provide access to rare intermediates in complex, multistage molecular pathways. However, few standards exist for processing these information-rich datasets, posing challenges for wider dissemination. Here, we present Mars, an open-source platform for storing and processing image-derived properties of biomolecules. Mars provides Fiji/ImageJ2 commands written in Java for common single-molecule analysis tasks using a Molecule Archive architecture that is easily adapted to complex, multistep analysis workflows. Three diverse workflows involving molecule tracking, multichannel fluorescence imaging, and force spectroscopy, demonstrate the range of analysis applications. A comprehensive graphical user interface written in JavaFX enhances biomolecule feature exploration by providing charting, tagging, region highlighting, scriptable dashboards, and interactive image views. The interoperability of ImageJ2 ensures Molecule Archives can easily be opened in multiple environments, including those written in Python using PyImageJ, for interactive scripting and visualization. Mars provides a flexible solution for reproducible analysis of image-derived properties, facilitating the discovery and quantitative classification of new biological phenomena with an open data format accessible to everyone.
Collapse
Affiliation(s)
- Nadia M Huisjes
- Structure and Dynamics of Molecular Machines, Max Planck Institute of BiochemistryMartinsriedGermany
| | - Thomas M Retzer
- Structure and Dynamics of Molecular Machines, Max Planck Institute of BiochemistryMartinsriedGermany
- Physik Department, Technische Universität MünchenGarchingGermany
| | - Matthias J Scherr
- Structure and Dynamics of Molecular Machines, Max Planck Institute of BiochemistryMartinsriedGermany
| | - Rohit Agarwal
- Structure and Dynamics of Molecular Machines, Max Planck Institute of BiochemistryMartinsriedGermany
- Physik Department, Technische Universität MünchenGarchingGermany
| | - Lional Rajappa
- Structure and Dynamics of Molecular Machines, Max Planck Institute of BiochemistryMartinsriedGermany
| | - Barbara Safaric
- Structure and Dynamics of Molecular Machines, Max Planck Institute of BiochemistryMartinsriedGermany
| | - Anita Minnen
- Structure and Dynamics of Molecular Machines, Max Planck Institute of BiochemistryMartinsriedGermany
| | - Karl E Duderstadt
- Structure and Dynamics of Molecular Machines, Max Planck Institute of BiochemistryMartinsriedGermany
- Physik Department, Technische Universität MünchenGarchingGermany
| |
Collapse
|
14
|
Berezney JP, Valentine MT. A compact rotary magnetic tweezers device for dynamic material analysis. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:093701. [PMID: 36182480 DOI: 10.1063/5.0090199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 07/18/2022] [Indexed: 06/16/2023]
Abstract
Here we present a new, compact magnetic tweezers design that enables precise application of a wide range of dynamic forces to soft materials without the need to raise or lower the magnet height above the sample. This is achieved through the controlled rotation of the permanent magnet array with respect to the fixed symmetry axis defined by a custom-built iron yoke. These design improvements increase the portability of the device and can be implemented within existing microscope setups without the need for extensive modification of the sample holders or light path. This device is particularly well-suited to active microrheology measurements using either creep analysis, in which a step force is applied to a micron-sized magnetic particle that is embedded in a complex fluid, or oscillatory microrheology, in which the particle is driven with a periodic waveform of controlled amplitude and frequency. In both cases, the motions of the particle are measured and analyzed to determine the local dynamic mechanical properties of the material.
Collapse
Affiliation(s)
- John P Berezney
- Mechanical Engineering Department, University of California, Santa Barbara, California 93106, USA
| | - Megan T Valentine
- Mechanical Engineering Department, University of California, Santa Barbara, California 93106, USA
| |
Collapse
|
15
|
Tan BG, Mutti CD, Shi Y, Xie X, Zhu X, Silva-Pinheiro P, Menger KE, Díaz-Maldonado H, Wei W, Nicholls TJ, Chinnery PF, Minczuk M, Falkenberg M, Gustafsson CM. The human mitochondrial genome contains a second light strand promoter. Mol Cell 2022; 82:3646-3660.e9. [PMID: 36044900 DOI: 10.1016/j.molcel.2022.08.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 07/21/2022] [Accepted: 08/07/2022] [Indexed: 11/30/2022]
Abstract
The human mitochondrial genome must be replicated and expressed in a timely manner to maintain energy metabolism and supply cells with adequate levels of adenosine triphosphate. Central to this process is the idea that replication primers and gene products both arise via transcription from a single light strand promoter (LSP) such that primer formation can influence gene expression, with no consensus as to how this is regulated. Here, we report the discovery of a second light strand promoter (LSP2) in humans, with features characteristic of a bona fide mitochondrial promoter. We propose that the position of LSP2 on the mitochondrial genome allows replication and gene expression to be orchestrated from two distinct sites, which expands our long-held understanding of mitochondrial gene expression in humans.
Collapse
Affiliation(s)
- Benedict G Tan
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg 405 30, Sweden
| | - Christian D Mutti
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Yonghong Shi
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg 405 30, Sweden
| | - Xie Xie
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg 405 30, Sweden
| | - Xuefeng Zhu
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg 405 30, Sweden
| | - Pedro Silva-Pinheiro
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Katja E Menger
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Héctor Díaz-Maldonado
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg 405 30, Sweden
| | - Wei Wei
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK; Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Thomas J Nicholls
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Patrick F Chinnery
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK; Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Michal Minczuk
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK.
| | - Maria Falkenberg
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg 405 30, Sweden.
| | - Claes M Gustafsson
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg 405 30, Sweden.
| |
Collapse
|
16
|
Pokhrel P, Hu C, Mao H. Ensemble Force Spectroscopy by Shear Forces. J Vis Exp 2022:10.3791/63741. [PMID: 35969056 PMCID: PMC10373445 DOI: 10.3791/63741] [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] [Indexed: 07/29/2023] Open
Abstract
Single-molecule techniques based on fluorescence and mechanochemical principles provide superior sensitivity in biological sensing. However, due to the lack of high throughput capabilities, the application of these techniques is limited in biophysics. Ensemble force spectroscopy (EFS) has demonstrated high throughput in the investigation of a massive set of molecular structures by converting mechanochemical studies of individual molecules into those of molecular ensembles. In this protocol, the DNA secondary structures (i-motifs) were unfolded in the shear flow between the rotor and stator of a homogenizer tip at shear rates up to 77796/s. The effects of flow rates and molecular sizes on the shear forces experienced by the i-motif were demonstrated. The EFS technique also revealed the binding affinity between DNA i-motifs and ligands. Furthermore, we have demonstrated a click chemistry reaction that can be actuated by shear force (i.e., mechano-click chemistry). These results establish the effectiveness of using shear force to control the conformation of molecular structures.
Collapse
Affiliation(s)
- Pravin Pokhrel
- Department of Chemistry & Biochemistry, Kent State University
| | - Changpeng Hu
- Department of Chemistry & Biochemistry, Kent State University
| | - Hanbin Mao
- Department of Chemistry & Biochemistry, Kent State University;
| |
Collapse
|
17
|
Chang TR, Long X, Shastry S, Parks JW, Stone MD. Single-Molecule Mechanical Analysis of Strand Invasion in Human Telomere DNA. Biochemistry 2022; 61:1554-1560. [PMID: 35852986 PMCID: PMC9352315 DOI: 10.1021/acs.biochem.1c00448] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Telomeres are essential
chromosome end capping structures that
safeguard the genome from dangerous DNA processing events. DNA strand
invasion occurs during vital transactions at telomeres, including
telomere length maintenance by the alternative lengthening of telomeres
(ALT) pathway. During telomeric strand invasion, a single-stranded
guanine-rich (G-rich) DNA invades at a complementary duplex telomere
repeat sequence, forming a displacement loop (D-loop) in which the
displaced DNA consists of the same G-rich sequence as the invading
single-stranded DNA. Single-stranded G-rich telomeric DNA readily
folds into stable, compact, structures called G-quadruplexes (GQs)
in vitro and is anticipated to form within the context of a D-loop;
however, evidence supporting this hypothesis is lacking. Here, we
report a magnetic tweezers assay that permits the controlled formation
of telomeric D-loops (TDLs) within uninterrupted duplex human telomere
DNA molecules of physiologically relevant lengths. Our results are
consistent with a model wherein the displaced single-stranded DNA
of a TDL fold into a GQ. This study provides new insight into telomere
structure and establishes a framework for the development of novel
therapeutics designed to target GQs at telomeres in cancer cells.
Collapse
Affiliation(s)
- Terren R. Chang
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High St, Santa Cruz, California 95064, United States
| | - Xi Long
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High St, Santa Cruz, California 95064, United States
| | - Shankar Shastry
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High St, Santa Cruz, California 95064, United States
- 10X Genomics, 6230 Stoneridge Mall Rd, Pleasanton, California 94588, United States
| | - Joseph W. Parks
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High St, Santa Cruz, California 95064, United States
- Invitae, 1400 16th St, San Francisco, California 94103, United States
| | - Michael D. Stone
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High St, Santa Cruz, California 95064, United States
| |
Collapse
|
18
|
Meyer AC, Karbach M, Lu P, Müller G. Mechanical response to tension and torque of molecular chains via statistically interacting particles associated with extension, contraction, twist, and supercoiling. Phys Rev E 2022; 105:064502. [PMID: 35854540 DOI: 10.1103/physreve.105.064502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 05/16/2022] [Indexed: 06/15/2023]
Abstract
A methodology for the statistical mechanical analysis of polymeric chains under tension introduced previously is extended to include torque. The response of individual bonds between monomers or of entire groups of monomers to a combination of tension and torque involves, in the framework of this method of analysis, the (thermal or mechanical) activation of a specific mix of statistically interacting particles carrying quanta of extension or contraction and quanta of twist or supercoiling. The methodology, which is elucidated in applications of increasing complexity, is capable of describing the conversion between twist chirality and plectonemic chirality in quasistatic processes. The control variables are force or extension and torque or linkage (a combination of twist and writhe). The versatility of this approach is demonstrated in two applications relevant and promising for double-stranded DNA under controlled tension and torque. One application describes conformational transformations between (native) B-DNA, (underwound) S-DNA, and (overwound) P-DNA in accord with experimental data. The other application describes how the conversion between a twisted chain and a supercoiled chain accommodates variations of linkage and excess length in a buckling transition.
Collapse
Affiliation(s)
- Aaron C Meyer
- Department of Physics, University of Rhode Island, Kingston Rhode Island 02881, USA
| | - Michael Karbach
- Fachgruppe Physik, Bergische Universität Wuppertal, D-42097 Wuppertal, Germany
| | - Ping Lu
- Department of Physics, Stetson University, DeLand, Florida 32723, USA
| | - Gerhard Müller
- Department of Physics, University of Rhode Island, Kingston Rhode Island 02881, USA
| |
Collapse
|
19
|
Stahlberger M, Steinlein O, Adam CR, Rotter M, Hohmann J, Nieger M, Köberle B, Bräse S. Fluorescent annulated imidazo[4,5- c]isoquinolines via a GBB-3CR/imidoylation sequence - DNA-interactions in pUC-19 gel electrophoresis mobility shift assay. Org Biomol Chem 2022; 20:3598-3604. [PMID: 35420107 DOI: 10.1039/d2ob00372d] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein we report the development of a sequential synthesis route towards annulated imidazo[4,5-c]isoquinolines comprising a GBB-3CR, followed by an intramolecular imidoylative cyclisation. X-Ray crystallography revealed a flat 3D structure of the obtained polyheterocycles. Thus, we evaluated their interactions with double-stranded DNA by establishing a pUC-19 plasmid-based gel electrophoresis mobility shift assay, revealing a stabilising effect on ds-DNA against strand-break inducing conditions.
Collapse
Affiliation(s)
- M Stahlberger
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany.
| | - O Steinlein
- Institute of Applied Biosciences, Department of Food Chemistry and Toxicology, Karlsruhe Institute of Technology (KIT), Adenauerring 20, 76131 Karlsruhe, Germany
| | - C R Adam
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany.
| | - M Rotter
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany.
| | - J Hohmann
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany.
| | - M Nieger
- Department of Chemistry, University of Helsinki, P.O. Box 55 (A. I. Virtasen aukio 1), 00014, Finland
| | - B Köberle
- Institute of Applied Biosciences, Department of Food Chemistry and Toxicology, Karlsruhe Institute of Technology (KIT), Adenauerring 20, 76131 Karlsruhe, Germany
| | - S Bräse
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany. .,Institute of Biological and Chemical Systems - IBCS-FMS, Karlsruhe Institute of Technology (KIT), Herman-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| |
Collapse
|
20
|
Ru XM, Yang ZY, Ran SY. Lanthanide ions induce DNA compaction with ionic specificity. Int J Biol Macromol 2022; 210:292-299. [DOI: 10.1016/j.ijbiomac.2022.04.182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/24/2022] [Accepted: 04/25/2022] [Indexed: 11/05/2022]
|
21
|
Boi L. A reappraisal of the form: function problem-theory and phenomenology. Theory Biosci 2022; 141:73-103. [PMID: 35471494 DOI: 10.1007/s12064-022-00368-8] [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: 08/03/2021] [Accepted: 03/11/2022] [Indexed: 11/26/2022]
Abstract
This paper is aimed at demonstrating that some geometrical and topological transformations and operations serve not only as promoters of many specific genetic and cellular events in multicellular living organisms, but also as initiators of the organization and regulation of their functions. Thus, changes in the form and structure of macromolecular and cellular systems must be directly associated to their functions. There are specific classes of enzymes that manipulate the geometry and topology of complex DNA-protein structures, and thereby they perform many important cellular processes, including segregation of daughter chromosomes, gene regulation, and DNA repair. We argue that form has an organizing power, hence a causal action, in the sense that it enables to induce functional events during different biological processes, at the supramolecular, cellular, and organismal levels of organization. Clearly, topological forms must be matched with specific kinetic and dynamical parameters to have a functional effectiveness in living systems. This effectiveness is remarkably apparent, to give an example, in the regulation of the genome functions and in cell activity. In more general terms, we try to show that the conformational plasticity of biological systems depends on different kinds of topological manipulations performed by specific families of enzymes. In doing so, they catalyze all those spatial and dynamical changes of biological structures that are suitable for the functions to be acted by the organism.
Collapse
Affiliation(s)
- Luciano Boi
- École des Hautes Études en Sciences Sociales, Centre de Mathématiques (CAMS), 54, bd Raspail, 75006, Paris, France.
| |
Collapse
|
22
|
Hormeno S, Wilkinson OJ, Aicart-Ramos C, Kuppa S, Antony E, Dillingham MS, Moreno-Herrero F. Human HELB is a processive motor protein that catalyzes RPA clearance from single-stranded DNA. Proc Natl Acad Sci U S A 2022; 119:e2112376119. [PMID: 35385349 PMCID: PMC9169624 DOI: 10.1073/pnas.2112376119] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 03/01/2022] [Indexed: 01/17/2023] Open
Abstract
Human DNA helicase B (HELB) is a poorly characterized helicase suggested to play both positive and negative regulatory roles in DNA replication and recombination. In this work, we used bulk and single-molecule approaches to characterize the biochemical activities of HELB protein with a particular focus on its interactions with Replication Protein A (RPA) and RPA–single-stranded DNA (ssDNA) filaments. HELB is a monomeric protein that binds tightly to ssDNA with a site size of ∼20 nucleotides. It couples ATP hydrolysis to translocation along ssDNA in the 5′ to 3′ direction accompanied by the formation of DNA loops. HELB also displays classical helicase activity, but this is very weak in the absence of an assisting force. HELB binds specifically to human RPA, which enhances its ATPase and ssDNA translocase activities but inhibits DNA unwinding. Direct observation of HELB on RPA nucleoprotein filaments shows that translocating HELB concomitantly clears RPA from ssDNA. This activity, which can allow other proteins access to ssDNA intermediates despite their shielding by RPA, may underpin the diverse roles of HELB in cellular DNA transactions.
Collapse
Affiliation(s)
- Silvia Hormeno
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
| | - Oliver J. Wilkinson
- DNA:Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Clara Aicart-Ramos
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
| | - Sahiti Kuppa
- Department of Biochemistry, Saint Louis University, St. Louis, MO 63104
| | - Edwin Antony
- Department of Biochemistry, Saint Louis University, St. Louis, MO 63104
| | - Mark S. Dillingham
- DNA:Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Fernando Moreno-Herrero
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
| |
Collapse
|
23
|
Raudsepp A, Williams MA, Jameson GB. Modeling multiple duplex DNA attachments in a force-extension experiment. BIOPHYSICAL REPORTS 2022; 2:100045. [PMID: 36425083 PMCID: PMC9680770 DOI: 10.1016/j.bpr.2022.100045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/20/2021] [Accepted: 01/28/2022] [Indexed: 11/30/2022]
Abstract
Optical tweezers-based DNA stretching often relies on tethering a single end-activated DNA molecule between optically manipulated end-binding beads. Measurement success can depend on DNA concentration. At lower DNA concentrations tethering is less common, and many trials may be required to observe a single-molecule stretch. At higher DNA concentrations tethering is more common; however, the resulting force-extensions observed are more complex and may vary from measurement to measurement. Typically these more complex results are attributed to the formation of multiple tethers between the beads; however, to date there does not appear to have been a critical examination of this hypothesis or the potential usefulness of such data. Here we examine stretches at a higher DNA concentration and use analysis and simulation to show how the more complex force-extensions observed can be understood in terms of multiple DNA attachments.
Collapse
|
24
|
Hu SQ, Ran SY. Single Molecular Chelation Dynamics Reveals That DNA Has a Stronger Affinity toward Lead(II) than Cadmium(II). J Phys Chem B 2022; 126:1876-1884. [PMID: 35196016 DOI: 10.1021/acs.jpcb.1c10487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Lead ions can bind to DNA via nonelectrostatic interactions and hence alter its structure, which may be related to their adverse effects. The dynamics of Pb2+-DNA interaction has not been well understood. In this study, we report the monomolecular dynamics of the Pb2+-DNA interaction using a magnetic tweezers (MT) setup. We found that lead cations could induce DNA compaction at ionic strengths above 1 μM, which was also confirmed by morphology characterization. The chelation behavior of the Pb2+-DNA and the Cd2+-DNA complex solutions after adding EDTA were compared. The results showed that EDTA chelated with the bound metal ions on DNA and consequently led to restoring the DNA to its original length but with different restoration speeds for the two solutions. The fast binding dynamics and the slower chelation dynamics of the Pb2+ scenario compared to that of Cd2+ suggested that Pb2+ was more capable to induce DNA conformational change and that the Pb2+-DNA complex was more stable than the Cd2+-DNA complex. The stronger affinities for DNA bases and the inner binding of lead cations were two possible causes of the dynamics differences. Three agents, including EDTA, sodium gluconate, and SDBS, were used to remove the bound lead ions on DNA. It was shown that EDTA was the most efficient, and sodium gluconate could not fully restore DNA from its compact state. We concluded that both EDTA and SDBS were good candidates to restore the Pb2+-bound DNA to its original state.
Collapse
Affiliation(s)
- Shu-Qian Hu
- Department of Physics, Wenzhou University, Wenzhou 325035, China
| | - Shi-Yong Ran
- Department of Physics, Wenzhou University, Wenzhou 325035, China
| |
Collapse
|
25
|
Shaali R, Doroodmand MM, Moazeni M. Helminth Eggs as a Magnetic Biomaterial: Introducing a Recognition Probe. Front Vet Sci 2022; 9:797304. [PMID: 35280143 PMCID: PMC8904871 DOI: 10.3389/fvets.2022.797304] [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: 10/18/2021] [Accepted: 01/06/2022] [Indexed: 11/13/2022] Open
Abstract
Parasitic helminths, despite their known negative impact (biomaterial) on human health and animal production, have fascinating features. In this study, we find fantastic magnetic properties in several forms: inductor [between 20.10 and 58.85 (±2.50) H], source of detectable electrical voltage [from +0.5 to 7.3 (±0.1) V, vs. the ground, GND, measured by an AVO meter] and different inductor magnitude [between 3.33 and 41.23 (±0.76)] μH, detected by electrochemical impedance spectroscopy as well as frequency scannable electromagnetic wave horn) in several frequencies (including 100, 120, Hz, and 1, 10, 100 kHz) in “Fasciola hepatica”, “Parascaris equorum” (with and without larvae), “Dicrocoelium dendriticum,” “Taenia multiceps”, and “Moniezia expansa” eggs. This claim is attributed to some surprising characteristics, including superior inductance and intrinsic magnetic susceptibility. This feature along with a close relationship to helminth egg structure, is a novel probe with acceptable reproducibility (RSD > 8.0%) and high enough trustworthiness for adequate differentiation in their magnitudes, relatively. These traits were measured by the “Single Cell Rrecording” methodology using a three-microelectrode system, implanted to each egg at the Giga ohm sealed condition (6.08 ± 0.22 GΩ cm−1, n = 5). The reliability of these results was further confirmed using multiple calibrated instruments such as a high-resolution inductance analyzer, LCR meter, impedance spectrometer, potentiometer, and an anomalous Hall effect (Magnetic field density) sensor. In addition, the critical role played (Synergistic Effect) by water-like molecules as the intermediate medium, besides the partial influence of other compounds such as dissolved oxygen, are investigated qualitatively, and specific relation between these molecules and magnetic field creation in helminth eggs was proved. These intrinsic characteristics would provide novel facilitators for efficient arriving at the researchable bio-based magnetic biomaterials, besides innovative and real-time identification probes in the “Parasitology” fields.
Collapse
Affiliation(s)
| | - Mohammad Mahdi Doroodmand
- Department of Chemistry, Shiraz University, Shiraz, Iran
- *Correspondence: Mohammad Mahdi Doroodmand ;
| | - Mohmmad Moazeni
- Department of Pathobiology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| |
Collapse
|
26
|
Wan B, Yu J. Two-phase dynamics of DNA supercoiling based on DNA polymer physics. Biophys J 2022; 121:658-669. [PMID: 35016860 PMCID: PMC8873955 DOI: 10.1016/j.bpj.2022.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 10/11/2021] [Accepted: 01/05/2022] [Indexed: 11/28/2022] Open
Abstract
DNA supercoils are generated in genome regulation processes such as transcription and replication and provide mechanical feedback to such processes. Under tension, a DNA supercoil can present a coexistence state of plectonemic and stretched phases. Experiments have revealed the dynamic behaviors of plectonemes, e.g., diffusion, nucleation, and hopping. To represent these dynamics with conformational changes, we demonstrated first the fast dynamics on the DNA to reach torque equilibrium within the plectonemic and stretched phases, and then identified the two-phase boundaries as collective slow variables to describe the essential dynamics. According to the timescale separation demonstrated here, we developed a two-phase model on the dynamics of DNA supercoiling, which can capture physiologically relevant events across timescales of several orders of magnitudes. In this model, we systematically characterized the slow dynamics between the two phases and compared the numerical results with those from the DNA polymer physics-based worm-like chain model. The supercoiling dynamics, including the nucleation, diffusion, and hopping of plectonemes, have been well represented and reproduced, using the two-phase dynamic model, at trivial computational costs. Our current developments, therefore, can be implemented to explore multiscale physical mechanisms of the DNA supercoiling-dependent physiological processes.
Collapse
Affiliation(s)
- Biao Wan
- Complex Systems Division, Beijing Computational Science Research Center, Beijing, China.
| | - Jin Yu
- Department of Physics and Astronomy, Department of Chemistry, NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, California.
| |
Collapse
|
27
|
Abstract
Single-molecule magnetic tweezers deliver magnetic force and torque to single target molecules, permitting the study of dynamic changes in biomolecular structures and their interactions. Because the magnetic tweezer setups can generate magnetic fields that vary slowly over tens of millimeters-far larger than the nanometer scale of the single molecule events being observed-this technique can maintain essentially constant force levels during biochemical experiments while generating a biologically meaningful force on the order of 1-100 pN. When using bead-tether constructs to pull on single molecules, smaller magnetic beads and shorter submicrometer tethers improve dynamic response times and measurement precision. In addition, employing high-speed cameras, stronger light sources, and a graphics programming unit permits true high-resolution single-molecule magnetic tweezers that can track nanometer changes in target molecules on a millisecond or even submillisecond time scale. The unique force-clamping capacity of the magnetic tweezer technique provides a way to conduct measurements under near-equilibrium conditions and directly map the energy landscapes underlying various molecular phenomena. High-resolution single-molecule magnetic tweezers can thus be used to monitor crucial conformational changes in single-protein molecules, including those involved in mechanotransduction and protein folding. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Collapse
Affiliation(s)
- Hyun-Kyu Choi
- Wallace H. Coulter Department of Biomedical Engineering and Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Hyun Gyu Kim
- School of Biological Sciences and Institute for Molecular Biology and Genetics, Seoul National University, Seoul, South Korea;
| | - Min Ju Shon
- Department of Physics and School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science & Technology (POSTECH), Pohang, South Korea;
| | - Tae-Young Yoon
- School of Biological Sciences and Institute for Molecular Biology and Genetics, Seoul National University, Seoul, South Korea;
| |
Collapse
|
28
|
Magnetic tweezers: development and use in single-molecule research. Biotechniques 2022; 72:65-72. [PMID: 35037472 DOI: 10.2144/btn-2021-0104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The use of magnetic tweezers for single-molecule micromanipulation has evolved rapidly since its introduction approximately 30 years ago. Magnetic tweezers have provided important insights into the dynamic activity of DNA-processing enzymes, as well as detailed, high-resolution information on the mechanical properties of DNA. These successes have been enabled by major advancements in the hardware and software components of these devices. These developments now allow for a much richer mechanistic understanding of the functions and mechanisms of DNA-binding enzymes. In this review, the authors briefly discuss the fundamental principles of magnetic tweezers and describe the advancements that have made it a superlative tool for investigating, at the single-molecule level, DNA and its interactions with DNA-binding proteins.
Collapse
|
29
|
Cross SJ, Brown CE, Baumann CG. Transverse Magnetic Tweezers Allowing Coincident Epi-Fluorescence Microscopy on Horizontally Extended DNA. Methods Mol Biol 2022; 2476:75-93. [PMID: 35635698 DOI: 10.1007/978-1-0716-2221-6_7] [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] [Indexed: 06/15/2023]
Abstract
Longitudinal magnetic tweezers (L-MT) have seen wide-scale adoption as the tool of choice for stretching and twisting a single DNA molecule. They are also used to probe topological changes in DNA as a result of protein binding and enzymatic activity. However, in the longitudinal configuration, the DNA molecule is extended perpendicular to the imaging plane. As a result, it is only possible to infer biological activity from the motion of the tethered paramagnetic microsphere. Described here is a "transverse" magnetic tweezers (T-MT) geometry featuring simultaneous control of DNA extension and spatially coincident video-rate epi-fluorescence imaging. Unlike in L-MT, DNA tethers in T-MT are extended parallel to the imaging plane between two micron-sized spheres, and importantly protein targets on the DNA can be localized using fluorescent nanoparticles. The T-MT can manipulate a long DNA construct at molecular extensions approaching the contour length defined by B-DNA helical geometry, and the measured entropic elasticity agrees with the wormlike chain model (force <35 pN). By incorporating a torsionally constrained DNA tether, the T-MT would allow both the relative extension and twist of the tether to be manipulated, while viewing far-red emitting fluorophore-labeled targets. This T-MT design has the potential to enable the study of DNA binding and remodeling processes under conditions of constant force and defined torsional stress.
Collapse
|
30
|
Aicart-Ramos C, Hormeno S, Wilkinson OJ, Dillingham MS, Moreno-Herrero F. Long DNA constructs to study helicases and nucleic acid translocases using optical tweezers. Methods Enzymol 2022; 673:311-358. [DOI: 10.1016/bs.mie.2022.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
31
|
Shepherd JW, Leake MC. The End Restraint Method for Mechanically Perturbing Nucleic Acids In Silico. Methods Mol Biol 2022; 2476:249-262. [PMID: 35635708 DOI: 10.1007/978-1-0716-2221-6_17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Far from being a passive information store, the genome is a mechanically dynamic and diverse system in which torsion and tension fluctuate and combine to determine structure and help regulate gene expression. Much of this mechanical perturbation is due to molecular machines such as topoisomerases which must stretch and twist DNA as part of various functions including DNA repair and replication. While the broad-scale mechanical response of nucleic acids to tension and torsion is well characterized, detail at the single base pair level is beyond the limits of even super-resolution imaging. Here, we present a straightforward, flexible, and extensible umbrella-sampling protocol to twist and stretch nucleic acids in silico using the popular biomolecular simulation package Amber-though the principles we describe are applicable also to other packages such as GROMACS. We discuss how to set up the simulation system, decide force fields and solvation models, and equilibrate. We then introduce the torsionally constrained stretching protocol, and finally we present some analysis techniques we have used to characterize structural motif formation. Rather than defining forces or fictional pseudoatoms, we instead define a fixed translation of specified atoms between each umbrella-sampling step, which allows comparison with experiment without needing to estimate applied forces by simply using the fractional end-to-end displacement as a comparison metric. We hope that this easy-to-implement solution will be valuable for interrogating optical and magnetic tweezers data on nucleic acids at base pair resolution.
Collapse
Affiliation(s)
| | - Mark C Leake
- Departments of Physics and Biology, University of York, York, UK
| |
Collapse
|
32
|
Salerno D, Marrano CA, Cassina V, Cristofalo M, Shao Q, Finzi L, Mantegazza F, Dunlap D. Nanomechanics of negatively supercoiled diaminopurine-substituted DNA. Nucleic Acids Res 2021; 49:11778-11786. [PMID: 34718727 PMCID: PMC8599871 DOI: 10.1093/nar/gkab982] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 10/05/2021] [Accepted: 10/13/2021] [Indexed: 11/25/2022] Open
Abstract
Single molecule experiments have demonstrated a progressive transition from a B- to an L-form helix as DNA is gently stretched and progressively unwound. The particular sequence of a DNA segment defines both base stacking and hydrogen bonding that affect the partitioning and conformations of the two phases. Naturally or artificially modified bases alter H-bonds and base stacking and DNA with diaminopurine (DAP) replacing adenine was synthesized to produce linear fragments with triply hydrogen-bonded DAP:T base pairs. Both unmodified and DAP-substituted DNA transitioned from a B- to an L-helix under physiological conditions of mild tension and unwinding. This transition avoids writhing and the ease of this transition may prevent cumbersome topological rearrangements in genomic DNA that would require topoisomerase activity to resolve. L-DNA displayed about tenfold lower persistence length than B-DNA. However, left-handed DAP-substituted DNA was twice as stiff as unmodified L-DNA. Unmodified DNA and DAP-substituted DNA have very distinct mechanical characteristics at physiological levels of negative supercoiling and tension.
Collapse
Affiliation(s)
- Domenico Salerno
- School of Medicine and Surgery, BioNanoMedicine Center NANOMIB, Università di Milano-Bicocca, via R. Follereau 3, Vedano al Lambro (MB), Italy
| | - Claudia Adriana Marrano
- School of Medicine and Surgery, BioNanoMedicine Center NANOMIB, Università di Milano-Bicocca, via R. Follereau 3, Vedano al Lambro (MB), Italy
| | - Valeria Cassina
- School of Medicine and Surgery, BioNanoMedicine Center NANOMIB, Università di Milano-Bicocca, via R. Follereau 3, Vedano al Lambro (MB), Italy
| | - Matteo Cristofalo
- School of Medicine and Surgery, BioNanoMedicine Center NANOMIB, Università di Milano-Bicocca, via R. Follereau 3, Vedano al Lambro (MB), Italy
| | - Qing Shao
- Department of Physics, Emory University, Atlanta, GA USA
| | - Laura Finzi
- Department of Physics, Emory University, Atlanta, GA USA
| | - Francesco Mantegazza
- School of Medicine and Surgery, BioNanoMedicine Center NANOMIB, Università di Milano-Bicocca, via R. Follereau 3, Vedano al Lambro (MB), Italy
| | - David Dunlap
- Department of Physics, Emory University, Atlanta, GA USA
| |
Collapse
|
33
|
Dubrovin EV, Klinov DV. Atomic Force Microscopy of Biopolymers on Graphite Surfaces. POLYMER SCIENCE SERIES A 2021. [DOI: 10.1134/s0965545x2106002x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
|
34
|
Piccolo JG, Méndez Harper J, McCalla D, Xu W, Miller S, Doan J, Kovari D, Dunlap D, Finzi L. Force spectroscopy with electromagnetic tweezers. JOURNAL OF APPLIED PHYSICS 2021; 130:134702. [PMID: 38681504 PMCID: PMC11055633 DOI: 10.1063/5.0060276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 09/07/2021] [Indexed: 05/01/2024]
Abstract
Force spectroscopy using magnetic tweezers (MTs) is a powerful method to probe the physical characteristics of single polymers. Typically, molecules are functionalized for specific attachment to a glass surface at one end and a micrometer-scale paramagnetic bead at the other end. By applying an external magnetic field, multiple molecules can be stretched and twisted simultaneously without exposure to potentially damaging radiation. The majority of MTs utilize mobile, permanent magnets to produce forces on the beads (and the molecule under test). However, translating and rotating the permanent magnets may require expensive precision actuators, limit the rate at which force can be changed, and may induce vibrations that disturb tether dynamics and bead tracking. Alternatively, the magnetic field can be produced with an electromagnet, which allows fast force modulation and eliminates motor-associated vibration. Here, we describe a low-cost quadrapolar electromagnetic tweezer design capable of manipulating DNA-tethered MyOne paramagnetic beads with forces as high as 15 pN. The solid-state nature of the generated B-field modulated along two axes is convenient for accessing the range of forces and torques relevant for studying the activity of DNA motor enzymes like polymerases and helicases. Our design specifically leverages technology available at an increasing number of university maker spaces and student-run machine shops. Thus, it is an accessible tool for undergraduate education that is applicable to a wide range of biophysical research questions.
Collapse
Affiliation(s)
- Joseph G. Piccolo
- Department of Physics, Emory University, 400 Dowman Dr., Atlanta, Georgia 30322, USA
| | - Joshua Méndez Harper
- Department of Earth Science, University of Oregon, 1272 University of Oregon, Eugene, Oregon 97403, USA
| | - Derrica McCalla
- Department of Physics, Emory University, 400 Dowman Dr., Atlanta, Georgia 30322, USA
| | - Wenxuan Xu
- Department of Physics, Emory University, 400 Dowman Dr., Atlanta, Georgia 30322, USA
| | - Sam Miller
- Department of Physics, Emory University, 400 Dowman Dr., Atlanta, Georgia 30322, USA
| | - Jessie Doan
- Department of Physics, Emory University, 400 Dowman Dr., Atlanta, Georgia 30322, USA
| | - Dan Kovari
- Department of Physics, Emory University, 400 Dowman Dr., Atlanta, Georgia 30322, USA
| | - David Dunlap
- Department of Physics, Emory University, 400 Dowman Dr., Atlanta, Georgia 30322, USA
| | - Laura Finzi
- Department of Physics, Emory University, 400 Dowman Dr., Atlanta, Georgia 30322, USA
| |
Collapse
|
35
|
Innes-Gold SN, Jacobson DR, Pincus PA, Stevens MJ, Saleh OA. Flexible, charged biopolymers in monovalent and mixed-valence salt: Regimes of anomalous electrostatic stiffening and of salt insensitivity. Phys Rev E 2021; 104:014504. [PMID: 34412211 DOI: 10.1103/physreve.104.014504] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 06/21/2021] [Indexed: 11/07/2022]
Abstract
The conformations of biological polyelectrolytes (PEs), such as polysaccharides, proteins, and nucleic acids, affect how they behave and interact with other biomolecules. Relative to neutral polymers, PEs in solution are more locally rigid due to intrachain electrostatic repulsion, the magnitude of which depends on the concentration of added salt. This is typically quantified using the Odijk-Skolnick-Fixman (OSF) electrostatic-stiffening model, in which salt-dependent Debye-Hückel (DH) screening modulates intrachain repulsion. However, the applicability of this approach to flexible PEs has long been questioned. To investigate this, we use high-precision single-molecule elasticity measurements to infer the scaling with salt of the local stiffness of three flexible biopolymers (hyaluronic acid, single-stranded RNA, and single-stranded DNA) in both monovalent and mixed-valence salt solutions. In monovalent salt, we collapse the data across all three polymers by accounting for charge spacing, and find a common power-law scaling of the electrostatic persistence length with ionic strength with an exponent of 0.66±0.02. This result rules out simple OSF pictures of electrostatic stiffening. It is roughly compatible with a modified OSF picture developed by Netz and Orland; alternatively, we posit the exponent can be explained if the relevant electrostatic screening length is the interion spacing rather than the DH length. In mixed salt solutions, we find a regime where adding monovalent salt, in the presence of multivalent salt, does not affect PE stiffness. Using coarse-grained simulations, and a three-state model of condensed, chain-proximate, and bulk ions, we attribute this regime to a "jacket" of ions surrounding the PE that regulates the chain's effective charge density as ionic strength varies. The size of this jacket in simulations is again consistent with a screening length controlled by interion spacing rather than the DH length. Taken together, our results describe a unified picture of the electrostatic stiffness of polyelectrolytes in the mixed-valence salt conditions of direct relevance to cellular and intercellular biological systems.
Collapse
Affiliation(s)
- Sarah N Innes-Gold
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - David R Jacobson
- Physics Department, University of California, Santa Barbara, California 93106, USA
| | - Philip A Pincus
- Materials Department and Physics Department, University of California, Santa Barbara, California 93106, USA
| | - Mark J Stevens
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Omar A Saleh
- Materials Department and Biomolecular Science and Engineering Program, University of California, Santa Barbara, California 93106, USA
| |
Collapse
|
36
|
Hu C, Jonchhe S, Pokhrel P, Karna D, Mao H. Mechanical unfolding of ensemble biomolecular structures by shear force. Chem Sci 2021; 12:10159-10164. [PMID: 34377405 PMCID: PMC8336480 DOI: 10.1039/d1sc02257a] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 07/11/2021] [Indexed: 01/09/2023] Open
Abstract
Mechanical unfolding of biomolecular structures has been exclusively performed at the single-molecule level by single-molecule force spectroscopy (SMFS) techniques. Here we transformed sophisticated mechanical investigations on individual molecules into a simple platform suitable for molecular ensembles. By using shear flow inside a homogenizer tip, DNA secondary structures such as i-motifs are unfolded by shear force up to 50 pN at a 77 796 s-1 shear rate. We found that the larger the molecules, the higher the exerted shear forces. This shear force approach revealed affinity between ligands and i-motif structures. It also demonstrated a mechano-click reaction in which a Cu(i) catalyzed azide-alkyne cycloaddition was modulated by shear force. We anticipate that this ensemble force spectroscopy method can investigate intra- and inter-molecular interactions with the throughput, accuracy, and robustness unparalleled to those of SMFS methods.
Collapse
Affiliation(s)
- Changpeng Hu
- Department of Chemistry & Biochemistry and School of Biomedical Sciences, Advanced Materials and Liquid Crystal Institute, Kent State University Kent OH 44242 USA
| | - Sagun Jonchhe
- Department of Chemistry & Biochemistry and School of Biomedical Sciences, Advanced Materials and Liquid Crystal Institute, Kent State University Kent OH 44242 USA
| | - Pravin Pokhrel
- Department of Chemistry & Biochemistry and School of Biomedical Sciences, Advanced Materials and Liquid Crystal Institute, Kent State University Kent OH 44242 USA
| | - Deepak Karna
- Department of Chemistry & Biochemistry and School of Biomedical Sciences, Advanced Materials and Liquid Crystal Institute, Kent State University Kent OH 44242 USA
| | - Hanbin Mao
- Department of Chemistry & Biochemistry and School of Biomedical Sciences, Advanced Materials and Liquid Crystal Institute, Kent State University Kent OH 44242 USA
| |
Collapse
|
37
|
Qian J, Xu W, Dunlap D, Finzi L. Single-molecule insights into torsion and roadblocks in bacterial transcript elongation. Transcription 2021; 12:219-231. [PMID: 34719335 PMCID: PMC8632135 DOI: 10.1080/21541264.2021.1997315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 12/12/2022] Open
Abstract
During transcription, RNA polymerase (RNAP) translocates along the helical template DNA while maintaining high transcriptional fidelity. However, all genomes are dynamically twisted, writhed, and decorated by bound proteins and motor enzymes. In prokaryotes, proteins bound to DNA, specifically or not, frequently compact DNA into conformations that may silence genes by obstructing RNAP. Collision of RNAPs with these architectural proteins, may result in RNAP stalling and/or displacement of the protein roadblock. It is important to understand how rapidly transcribing RNAPs operate under different levels of supercoiling or in the presence of roadblocks. Given the broad range of asynchronous dynamics exhibited by transcriptional complexes, single-molecule assays, such as atomic force microscopy, fluorescence detection, optical and magnetic tweezers, etc. are well suited for detecting and quantifying activity with adequate spatial and temporal resolution. Here, we summarize current understanding of the effects of torsion and roadblocks on prokaryotic transcription, with a focus on single-molecule assays that provide real-time detection and readout.
Collapse
Affiliation(s)
- Jin Qian
- Emory University, Atlanta, GA, USA
| | | | | | | |
Collapse
|
38
|
Balaguer FDA, Aicart-Ramos C, Fisher GL, de Bragança S, Martin-Cuevas EM, Pastrana CL, Dillingham MS, Moreno-Herrero F. CTP promotes efficient ParB-dependent DNA condensation by facilitating one-dimensional diffusion from parS. eLife 2021; 10:67554. [PMID: 34250901 PMCID: PMC8299390 DOI: 10.7554/elife.67554] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 07/09/2021] [Indexed: 12/19/2022] Open
Abstract
Faithful segregation of bacterial chromosomes relies on the ParABS partitioning system and the SMC complex. In this work, we used single-molecule techniques to investigate the role of cytidine triphosphate (CTP) binding and hydrolysis in the critical interaction between centromere-like parS DNA sequences and the ParB CTPase. Using a combined optical tweezers confocal microscope, we observe the specific interaction of ParB with parS directly. Binding around parS is enhanced by the presence of CTP or the non-hydrolysable analogue CTPγS. However, ParB proteins are also detected at a lower density in distal non-specific DNA. This requires the presence of a parS loading site and is prevented by protein roadblocks, consistent with one-dimensional diffusion by a sliding clamp. ParB diffusion on non-specific DNA is corroborated by direct visualization and quantification of movement of individual quantum dot labelled ParB. Magnetic tweezers experiments show that the spreading activity, which has an absolute requirement for CTP binding but not hydrolysis, results in the condensation of parS-containing DNA molecules at low nanomolar protein concentrations.
Collapse
Affiliation(s)
- Francisco de Asis Balaguer
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Clara Aicart-Ramos
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Gemma Lm Fisher
- DNA:Protein Interactions Unit, School of Biochemistry, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, United Kingdom
| | - Sara de Bragança
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Eva M Martin-Cuevas
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Cesar L Pastrana
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Mark Simon Dillingham
- DNA:Protein Interactions Unit, School of Biochemistry, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, United Kingdom
| | - Fernando Moreno-Herrero
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| |
Collapse
|
39
|
Spakman D, Bakx JAM, Biebricher AS, Peterman EJG, Wuite GJL, King GA. Unravelling the mechanisms of Type 1A topoisomerases using single-molecule approaches. Nucleic Acids Res 2021; 49:5470-5492. [PMID: 33963870 PMCID: PMC8191776 DOI: 10.1093/nar/gkab239] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 03/19/2021] [Accepted: 05/05/2021] [Indexed: 12/14/2022] Open
Abstract
Topoisomerases are essential enzymes that regulate DNA topology. Type 1A family topoisomerases are found in nearly all living organisms and are unique in that they require single-stranded (ss)DNA for activity. These enzymes are vital for maintaining supercoiling homeostasis and resolving DNA entanglements generated during DNA replication and repair. While the catalytic cycle of Type 1A topoisomerases has been long-known to involve an enzyme-bridged ssDNA gate that allows strand passage, a deeper mechanistic understanding of these enzymes has only recently begun to emerge. This knowledge has been greatly enhanced through the combination of biochemical studies and increasingly sophisticated single-molecule assays based on magnetic tweezers, optical tweezers, atomic force microscopy and Förster resonance energy transfer. In this review, we discuss how single-molecule assays have advanced our understanding of the gate opening dynamics and strand-passage mechanisms of Type 1A topoisomerases, as well as the interplay of Type 1A topoisomerases with partner proteins, such as RecQ-family helicases. We also highlight how these assays have shed new light on the likely functional roles of Type 1A topoisomerases in vivo and discuss recent developments in single-molecule technologies that could be applied to further enhance our understanding of these essential enzymes.
Collapse
Affiliation(s)
- Dian Spakman
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Julia A M Bakx
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Andreas S Biebricher
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Erwin J G Peterman
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Gijs J L Wuite
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Graeme A King
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
| |
Collapse
|
40
|
Xu W, Dunlap D, Finzi L. Energetics of twisted DNA topologies. Biophys J 2021; 120:3242-3252. [PMID: 33974883 DOI: 10.1016/j.bpj.2021.05.002] [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: 11/19/2020] [Revised: 03/30/2021] [Accepted: 05/05/2021] [Indexed: 11/30/2022] Open
Abstract
Our goal is to review the main theoretical models used to calculate free energy changes associated with common, torsion-induced conformational changes in DNA and provide the resulting equations hoping to facilitate quantitative analysis of both in vitro and in vivo studies. This review begins with a summary of work regarding the energy change of the negative supercoiling-induced B- to L-DNA transition, followed by a discussion of the energetics associated with the transition to Z-form DNA. Finally, it describes the energy changes associated with the formation of DNA curls and plectonemes, which can regulate DNA-protein interactions and promote cross talk between distant DNA elements, respectively. The salient formulas and parameters for each scenario are summarized in table format to facilitate comparison and provide a concise, user-friendly resource.
Collapse
Affiliation(s)
- Wenxuan Xu
- Emory University, Department of Physics, Atlanta, Georgia
| | - David Dunlap
- Emory University, Department of Physics, Atlanta, Georgia
| | - Laura Finzi
- Emory University, Department of Physics, Atlanta, Georgia.
| |
Collapse
|
41
|
Urbanska M, Lüdecke A, Walter WJ, van Oijen AM, Duderstadt KE, Diez S. Highly-Parallel Microfluidics-Based Force Spectroscopy on Single Cytoskeletal Motors. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2007388. [PMID: 33759372 DOI: 10.1002/smll.202007388] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/22/2021] [Indexed: 06/12/2023]
Abstract
Cytoskeletal motors transform chemical energy into mechanical work to drive essential cellular functions. Optical trapping experiments have provided crucial insights into the operation of these molecular machines under load. However, the throughput of such force spectroscopy experiments is typically limited to one measurement at a time. Here, a highly-parallel, microfluidics-based method that allows for rapid collection of force-dependent motility parameters of cytoskeletal motors with two orders of magnitude improvement in throughput compared to currently available methods is introduced. Tunable hydrodynamic forces to stepping kinesin-1 motors via DNA-tethered beads and utilize a large field of view to simultaneously track the velocities, run lengths, and interaction times of hundreds of individual kinesin-1 molecules under varying resisting and assisting loads are applied. Importantly, the 16 µm long DNA tethers between the motors and the beads significantly reduces the vertical component of the applied force pulling the motors away from the microtubule. The approach is readily applicable to other molecular systems and constitutes a new methodology for parallelized single-molecule force studies on cytoskeletal motors.
Collapse
Affiliation(s)
- Marta Urbanska
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, 01069, Dresden, Germany
| | - Annemarie Lüdecke
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, 01069, Dresden, Germany
| | - Wilhelm J Walter
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, 01069, Dresden, Germany
| | - Antoine M van Oijen
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, AE, 9700, Netherlands
- Molecular Horizons, University of Wollongong, Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia
| | - Karl E Duderstadt
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, AE, 9700, Netherlands
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
- Physics Department, Technische Universität München, 85748, Garching, Germany
| | - Stefan Diez
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, 01069, Dresden, Germany
- Cluster of Excellence Physics of Life, Technische Universität Dresden, 01062, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany
| |
Collapse
|
42
|
Single-molecule micromanipulation studies of methylated DNA. Biophys J 2021; 120:2148-2155. [PMID: 33838135 DOI: 10.1016/j.bpj.2021.03.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 03/21/2021] [Accepted: 03/23/2021] [Indexed: 12/31/2022] Open
Abstract
Cytosine methylated at the five-carbon position is the most widely studied reversible DNA modification. Prior findings indicate that methylation can alter mechanical properties. However, those findings were qualitative and sometimes contradictory, leaving many aspects unclear. By applying single-molecule magnetic force spectroscopy techniques allowing for direct manipulation and dynamic observation of DNA mechanics and mechanically driven strand separation, we investigated how CpG and non-CpG cytosine methylation affects DNA micromechanical properties. We quantitatively characterized DNA stiffness using persistence length measurements from force-extension curves in the nanoscale length regime and demonstrated that cytosine methylation results in longer contour length and increased DNA flexibility (i.e., decreased persistence length). In addition, we observed the preferential formation of plectonemes over unwound single-stranded "bubbles" of DNA under physiologically relevant stretching forces and supercoiling densities. The flexibility and high structural stability of methylated DNA is likely to have significant consequences on the recruitment of proteins recognizing cytosine methylation and DNA packaging.
Collapse
|
43
|
Abstract
R-loops are nucleic acid hybrids which form when an RNA invades duplex DNA to pair with its template sequence. Although they are implicated in a growing number of gene regulatory processes, their mechanistic origins remain unclear. We here report real-time observations of cotranscriptional R-loop formation at single-molecule resolution and propose a mechanism for their formation. We show that the bacterial Mfd protein can simultaneously interact with both elongating RNA polymerase and upstream DNA, tethering the two together and partitioning the DNA into distinct supercoiled domains. A highly negatively supercoiled domain forms in between Mfd and RNA polymerase, and compensatory positive supercoiling appears in front of the RNA polymerase and behind Mfd. The nascent RNA invades the negatively supercoiled domain and forms a stable R-loop that can drive mutagenesis. This mechanism theoretically enables any protein that simultaneously binds an actively translocating RNA polymerase and upstream DNA to stimulate R-loop formation.
Collapse
|
44
|
Takahashi S, Oshige M, Katsura S. DNA Manipulation and Single-Molecule Imaging. Molecules 2021; 26:1050. [PMID: 33671359 PMCID: PMC7922115 DOI: 10.3390/molecules26041050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 02/12/2021] [Accepted: 02/14/2021] [Indexed: 11/22/2022] Open
Abstract
DNA replication, repair, and recombination in the cell play a significant role in the regulation of the inheritance, maintenance, and transfer of genetic information. To elucidate the biomolecular mechanism in the cell, some molecular models of DNA replication, repair, and recombination have been proposed. These biological studies have been conducted using bulk assays, such as gel electrophoresis. Because in bulk assays, several millions of biomolecules are subjected to analysis, the results of the biological analysis only reveal the average behavior of a large number of biomolecules. Therefore, revealing the elementary biological processes of a protein acting on DNA (e.g., the binding of protein to DNA, DNA synthesis, the pause of DNA synthesis, and the release of protein from DNA) is difficult. Single-molecule imaging allows the analysis of the dynamic behaviors of individual biomolecules that are hidden during bulk experiments. Thus, the methods for single-molecule imaging have provided new insights into almost all of the aspects of the elementary processes of DNA replication, repair, and recombination. However, in an aqueous solution, DNA molecules are in a randomly coiled state. Thus, the manipulation of the physical form of the single DNA molecules is important. In this review, we provide an overview of the unique studies on DNA manipulation and single-molecule imaging to analyze the dynamic interaction between DNA and protein.
Collapse
Affiliation(s)
- Shunsuke Takahashi
- Division of Life Science and Engineering, School of Science and Engineering, Tokyo Denki University, Hatoyama-cho, Hiki-gun, Saitama 350-0394, Japan;
| | - Masahiko Oshige
- Department of Environmental Engineering Science, Graduate School of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan;
- Gunma University Center for Food Science and Wellness (GUCFW), Maebashi, Gunma 371-8510, Japan
| | - Shinji Katsura
- Department of Environmental Engineering Science, Graduate School of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan;
- Gunma University Center for Food Science and Wellness (GUCFW), Maebashi, Gunma 371-8510, Japan
| |
Collapse
|
45
|
Everaers R, Becker NB, Rosa A. Single-molecule stretching experiments of flexible (wormlike) chain molecules in different ensembles: Theory and a potential application of finite chain length effects to nick-counting in DNA. J Chem Phys 2021; 154:024903. [PMID: 33445920 DOI: 10.1063/5.0028777] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We propose a formalism for deriving force-elongation and elongation-force relations for flexible chain molecules from analytical expressions for their radial distribution function, which provides insight into the factors controlling the asymptotic behavior and finite chain length corrections. In particular, we apply this formalism to our previously developed interpolation formula for the wormlike chain end-to-end distance distribution. The resulting expression for the asymptotic limit of infinite chain length is of similar quality to the numerical evaluation of Marko and Siggia's variational theory and considerably more precise than their interpolation formula. A comparison to numerical data suggests that our analytical finite chain length corrections achieve a comparable accuracy. As an application of our results, we discuss the possibility of inferring the time-dependent number of nicks in single-molecule stretching experiments on double-stranded DNA from the accompanying changes in the effective chain length.
Collapse
Affiliation(s)
- Ralf Everaers
- Université Lyon, ENS de Lyon, CNRS, Laboratoire de Physique and Centre Blaise Pascal, F-69342 Lyon, France
| | - Nils B Becker
- German Cancer Research Center, Neuenheimer Feld 580, D-69120 Heidelberg, Germany
| | - Angelo Rosa
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, 34136 Trieste, Italy
| |
Collapse
|
46
|
Gutierrez-Escribano P, Hormeño S, Madariaga-Marcos J, Solé-Soler R, O'Reilly FJ, Morris K, Aicart-Ramos C, Aramayo R, Montoya A, Kramer H, Rappsilber J, Torres-Rosell J, Moreno-Herrero F, Aragon L. Purified Smc5/6 Complex Exhibits DNA Substrate Recognition and Compaction. Mol Cell 2020; 80:1039-1054.e6. [PMID: 33301732 PMCID: PMC7758880 DOI: 10.1016/j.molcel.2020.11.012] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 10/12/2020] [Accepted: 11/04/2020] [Indexed: 02/03/2023]
Abstract
Eukaryotic SMC complexes, cohesin, condensin, and Smc5/6, use ATP hydrolysis to power a plethora of functions requiring organization and restructuring of eukaryotic chromosomes in interphase and during mitosis. The Smc5/6 mechanism of action and its activity on DNA are largely unknown. Here we purified the budding yeast Smc5/6 holocomplex and characterized its core biochemical and biophysical activities. Purified Smc5/6 exhibits DNA-dependent ATP hydrolysis and SUMO E3 ligase activity. We show that Smc5/6 binds DNA topologically with affinity for supercoiled and catenated DNA templates. Employing single-molecule assays to analyze the functional and dynamic characteristics of Smc5/6 bound to DNA, we show that Smc5/6 locks DNA plectonemes and can compact DNA in an ATP-dependent manner. These results demonstrate that the Smc5/6 complex recognizes DNA tertiary structures involving juxtaposed helices and might modulate DNA topology by plectoneme stabilization and local compaction.
Collapse
Affiliation(s)
| | - Silvia Hormeño
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Julene Madariaga-Marcos
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Roger Solé-Soler
- Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Department of Ciències Mèdiques Bàsiques, Universitat de Lleida, Lleida, Spain
| | - Francis J O'Reilly
- Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, 13355 Berlin, Germany; Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Kyle Morris
- Microscopy Facility, MRC London Institute of Medical Sciences (LMS), Du Cane Road, London W12 0NN, UK
| | - Clara Aicart-Ramos
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Ricardo Aramayo
- Microscopy Facility, MRC London Institute of Medical Sciences (LMS), Du Cane Road, London W12 0NN, UK
| | - Alex Montoya
- Biological Mass Spectrometry and Proteomics Facility, MRC London Institute of Medical Sciences (LMS), Du Cane Road, London W12 0NN, UK
| | - Holger Kramer
- Biological Mass Spectrometry and Proteomics Facility, MRC London Institute of Medical Sciences (LMS), Du Cane Road, London W12 0NN, UK
| | - Juri Rappsilber
- Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, 13355 Berlin, Germany; Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Jordi Torres-Rosell
- Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Department of Ciències Mèdiques Bàsiques, Universitat de Lleida, Lleida, Spain
| | - Fernando Moreno-Herrero
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
| | - Luis Aragon
- Cell Cycle Group, MRC London Institute of Medical Sciences (LMS), Du Cane Road, London W12 0NN, UK.
| |
Collapse
|
47
|
Innes-Gold SN, Berezney JP, Saleh OA. Single-Molecule Stretching Shows Glycosylation Sets Tension in the Hyaluronan-Aggrecan Bottlebrush. Biophys J 2020; 119:1351-1358. [PMID: 32918890 DOI: 10.1016/j.bpj.2020.08.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 08/13/2020] [Accepted: 08/17/2020] [Indexed: 11/18/2022] Open
Abstract
Large bottlebrush complexes formed from the polysaccharide hyaluronan (HA) and the proteoglycan aggrecan contribute to cartilage compression resistance and are necessary for healthy joint function. A variety of mechanical forces act on these complexes in the cartilage extracellular matrix, motivating the need for a quantitative description that links their structure and mechanical response. Studies using electron microscopy have imaged the HA-aggrecan brush but require adsorption to a surface, dramatically altering the complex from its native conformation. We use magnetic tweezers force spectroscopy to measure changes in extension and mechanical response of an HA chain as aggrecan monomers bind and form a bottlebrush. This technique directly measures changes undergone by a single complex with time and under varying solution conditions. Upon addition of aggrecan, we find a large swelling effect manifests when the HA chain is under very low external tension (i.e., stretching forces less than ∼1 pN). We use models of force-extension behavior to show that repulsion between the aggrecans induces an internal tension in the HA chain. Through reference to theories of bottlebrush polymer behavior, we demonstrate that the experimental values of internal tension are consistent with a polydisperse aggrecan population, likely caused by varying degrees of glycosylation. By enzymatically deglycosylating the aggrecan, we show that aggrecan glycosylation is the structural feature that causes HA stiffening. We then construct a simple stochastic binding model to show that variable glycosylation leads to a wide distribution of internal tensions in HA, causing variations in the mechanics at much longer length scales. Our results provide a mechanistic picture of how flexibility and size of HA and aggrecan lead to the brush architecture and mechanical properties of this important component of cartilage.
Collapse
Affiliation(s)
- Sarah N Innes-Gold
- Materials Department, University of California, Santa Barbara, Santa Barbara, California
| | - John P Berezney
- Materials Department, University of California, Santa Barbara, Santa Barbara, California
| | - Omar A Saleh
- Materials Department, University of California, Santa Barbara, Santa Barbara, California; Biomolecular Science and Engineering Program, University of California, Santa Barbara, Santa Barbara, California.
| |
Collapse
|
48
|
Liu YF, Ran SY. Divalent metal ions and intermolecular interactions facilitate DNA network formation. Colloids Surf B Biointerfaces 2020; 194:111117. [PMID: 32512310 DOI: 10.1016/j.colsurfb.2020.111117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 04/30/2020] [Accepted: 05/06/2020] [Indexed: 02/08/2023]
Abstract
The interactions between divalent metal ions and DNA are crucial for basic life processes. These interactions are also important in advanced technological products such as DNA-based ion sensors. Current polyelectrolyte theories cannot describe these interactions well and do not consider the corresponding dynamics. In this study, we report the single-molecule dynamics of the binding of divalent metal ions to a single DNA molecule and the morphology characterization of the complex. We found that most of the divalent metal ions (Mn2+, Zn2+, Co2+, Ni2+, and Cd2+), except Mg2+ and Ca2+, could cause monomolecular DNA condensation. For transition metal ions, different ionic strengths were required to induce the compaction, and different shortening speeds were displayed in the dynamics, indicating ionic specificity. Atomic force microscopy revealed that the morphologies of the metal ion-DNA complexes were affected by the ionic strength of the metal ion, DNA chain length, and DNA concentration. At low metal ion concentration, DNA tended to adopt a random coil conformation. Increasing the ionic strength led to network-like condensed structures, suggesting that divalent metal ions can induce attraction between DNA molecules. Furthermore, higher DNA concentration and longer chain length enhanced intermolecular interactions and consequently resulted in network structures with a higher degree of interconnectivity.
Collapse
Affiliation(s)
- Yin-Feng Liu
- Department of Physics, Wenzhou University, Wenzhou 325035, China
| | - Shi-Yong Ran
- Department of Physics, Wenzhou University, Wenzhou 325035, China.
| |
Collapse
|
49
|
Wilkinson OJ, Carrasco C, Aicart-Ramos C, Moreno-Herrero F, Dillingham MS. Bulk and single-molecule analysis of a bacterial DNA2-like helicase-nuclease reveals a single-stranded DNA looping motor. Nucleic Acids Res 2020; 48:7991-8005. [PMID: 32621607 PMCID: PMC7430649 DOI: 10.1093/nar/gkaa562] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 06/12/2020] [Accepted: 06/19/2020] [Indexed: 11/14/2022] Open
Abstract
DNA2 is an essential enzyme involved in DNA replication and repair in eukaryotes. In a search for homologues of this protein, we identified and characterised Geobacillus stearothermophilus Bad, a bacterial DNA helicase-nuclease with similarity to human DNA2. We show that Bad contains an Fe-S cluster and identify four cysteine residues that are likely to co-ordinate the cluster by analogy to DNA2. The purified enzyme specifically recognises ss-dsDNA junctions and possesses ssDNA-dependent ATPase, ssDNA binding, ssDNA endonuclease, 5' to 3' ssDNA translocase and 5' to 3' helicase activity. Single molecule analysis reveals that Bad is a processive DNA motor capable of moving along DNA for distances of >4 kb at a rate of ∼200 bp per second at room temperature. Interestingly, as reported for the homologous human and yeast DNA2 proteins, the DNA unwinding activity of Bad is cryptic and can be unmasked by inactivating the intrinsic nuclease activity. Strikingly, our experiments show that the enzyme loops DNA while translocating, which is an emerging feature of processive DNA unwinding enzymes. The bacterial Bad enzymes will provide an excellent model system for understanding the biochemical properties of DNA2-like helicase-nucleases and DNA looping motor proteins in general.
Collapse
Affiliation(s)
- Oliver J Wilkinson
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Carolina Carrasco
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Cantoblanco, Madrid, Spain
| | - Clara Aicart-Ramos
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Cantoblanco, Madrid, Spain
| | - Fernando Moreno-Herrero
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Cantoblanco, Madrid, Spain
| | - Mark S Dillingham
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| |
Collapse
|
50
|
Agarwal R, Duderstadt KE. Multiplex flow magnetic tweezers reveal rare enzymatic events with single molecule precision. Nat Commun 2020; 11:4714. [PMID: 32948754 PMCID: PMC7501243 DOI: 10.1038/s41467-020-18456-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 08/21/2020] [Indexed: 02/08/2023] Open
Abstract
The application of forces and torques on the single molecule level has transformed our understanding of the dynamic properties of biomolecules, but rare intermediates have remained difficult to characterize due to limited throughput. Here, we describe a method that provides a 100-fold improvement in the throughput of force spectroscopy measurements with topological control, which enables routine imaging of 50,000 single molecules and a 100 million reaction cycles in parallel. This improvement enables detection of rare events in the life cycle of the cell. As a demonstration, we characterize the supercoiling dynamics and drug-induced DNA break intermediates of topoisomerases. To rapidly quantify distinct classes of dynamic behaviors and rare events, we developed a software platform with an automated feature classification pipeline. The method and software can be readily adapted for studies of a broad range of complex, multistep enzymatic pathways in which rare intermediates have escaped classification due to limited throughput.
Collapse
Affiliation(s)
- Rohit Agarwal
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Martinsried, Germany
- Physik Department, Technische Universität München, Garching, Germany
| | - Karl E Duderstadt
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Martinsried, Germany.
- Physik Department, Technische Universität München, Garching, Germany.
| |
Collapse
|