1
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Kolesnikov ES, Xiong Y, Onufriev AV. Implicit Solvent with Explicit Ions Generalized Born Model in Molecular Dynamics: Application to DNA. J Chem Theory Comput 2024. [PMID: 39283928 DOI: 10.1021/acs.jctc.4c00833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2024]
Abstract
The ion atmosphere surrounding highly charged biomolecules, such as nucleic acids, is crucial for their dynamics, structure, and interactions. Here, we develop an approach for the explicit treatment of ions within an implicit solvent framework suitable for atomistic simulations of biomolecules. The proposed implicit solvent/explicit ions model, GBION, is based on a modified generalized Born (GB) model; it includes separate, modified GB terms for solute-ion and ion-ion interactions. The model is implemented in the AMBER package (version 24), and its performance is thoroughly investigated in atomistic molecular dynamics (MD) simulations of double-stranded DNA on a microsecond time scale. The aggregate characteristics of monovalent (Na+ and K+) and trivalent (Cobalt Hexammine, CoHex3+) counterion distributions around double-stranded DNA predicted by the model are in reasonable agreement with the experiment (where available), all-atom explicit water MD simulations, and the expectation from the Manning condensation theory. The radial distributions of monovalent cations around DNA are reasonably close to the ones obtained using the explicit water model: expressed in units of energy, the maximum deviations of local ion concentrations from the explicit solvent reference are within 1 kBT, comparable to the corresponding deviations expected between different established explicit water models. The proposed GBION model is able to simulate DNA fragments in a large volume of solvent with explicit ions with little additional computational overhead compared with the fully implicit GB treatment of ions. Ions simulated using the developed model explore conformational space at least 2 orders of magnitude faster than in the explicit solvent. These advantages allowed us to observe and explore an unexpected "stacking" mode of DNA condensation in the presence of trivalent counterions (CoHex3+) that was revealed by recent experiments.
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Affiliation(s)
- Egor S Kolesnikov
- Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Yeyue Xiong
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Alexey V Onufriev
- Departments of Computer Science and Physics, Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, Virginia 24061, United States
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2
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Zheng CC, Chen YL, Dong HL, Zhang XH, Tan ZJ. Effect of ethanol on the elasticities of double-stranded RNA and DNA revealed by magnetic tweezers and simulations. J Chem Phys 2024; 161:075101. [PMID: 39145565 DOI: 10.1063/5.0211869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 07/29/2024] [Indexed: 08/16/2024] Open
Abstract
The elasticities of double-stranded (ds) DNA and RNA, which are critical to their biological functions and applications in materials science, can be significantly modulated by solution conditions such as ions and temperature. However, there is still a lack of a comprehensive understanding of the role of solvents in the elasticities of dsRNA and dsDNA in a comparative way. In this work, we explored the effect of ethanol solvent on the elasticities of dsRNA and dsDNA by magnetic tweezers and all-atom molecular dynamics simulations. We found that the bending persistence lengths and contour lengths of dsRNA and dsDNA decrease monotonically with the increase in ethanol concentration. Furthermore, the addition of ethanol weakens the positive twist-stretch coupling of dsRNA, while promotes the negative twist-stretch coupling of dsDNA. Counter-intuitively, the lower dielectric environment of ethanol causes a significant re-distribution of counterions and enhanced ion neutralization, which overwhelms the enhanced repulsion along dsRNA/dsDNA, ultimately leading to the softening in bending for dsRNA and dsDNA. Moreover, for dsRNA, ethanol causes slight ion-clamping across the major groove, which weakens the major groove-mediated twist-stretch coupling, while for dsDNA, ethanol promotes the stretch-radius correlation due to enhanced ion binding and consequently enhances the helical radius-mediated twist-stretch coupling.
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Affiliation(s)
- Chen-Chen Zheng
- School of Physics and Technology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Yun-Long Chen
- School of Physics and Technology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Hai-Long Dong
- School of Physics and Technology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xing-Hua Zhang
- School of Physics and Technology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Zhi-Jie Tan
- School of Physics and Technology, College of Life Sciences, Wuhan University, Wuhan 430072, China
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3
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Kretzer B, Herényi L, Csík G, Supala E, Orosz Á, Tordai H, Kiss B, Kellermayer M. TMPyP binding evokes a complex, tunable nanomechanical response in DNA. Nucleic Acids Res 2024; 52:8399-8418. [PMID: 38943349 PMCID: PMC11317170 DOI: 10.1093/nar/gkae560] [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: 10/17/2023] [Revised: 06/06/2024] [Accepted: 06/17/2024] [Indexed: 07/01/2024] Open
Abstract
TMPyP is a porphyrin capable of DNA binding and used in photodynamic therapy and G-quadruplex stabilization. Despite its broad applications, TMPyP's effect on DNA nanomechanics is unknown. Here we investigated, by manipulating λ-phage DNA with optical tweezers combined with microfluidics in equilibrium and perturbation kinetic experiments, how TMPyP influences DNA nanomechanics across wide ranges of TMPyP concentration (5-5120 nM), mechanical force (0-100 pN), NaCl concentration (0.01-1 M) and pulling rate (0.2-20 μm/s). Complex responses were recorded, for the analysis of which we introduced a simple mathematical model. TMPyP binding, which is a highly dynamic process, leads to dsDNA lengthening and softening. dsDNA stability increased at low (<10 nM) TMPyP concentrations, then decreased progressively upon increasing TMPyP concentration. Overstretch cooperativity decreased, due most likely to mechanical roadblocks of ssDNA-bound TMPyP. TMPyP binding increased ssDNA's contour length. The addition of NaCl at high (1 M) concentration competed with the TMPyP-evoked nanomechanical changes. Because the largest amplitude of the changes is induced by the pharmacologically relevant TMPyP concentration range, this porphyrin derivative may be used to tune DNA's structure and properties, hence control the wide array of biomolecular DNA-dependent processes including replication, transcription, condensation and repair.
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Affiliation(s)
- Balázs Kretzer
- Department of Biophysics and Radiation Biology, Semmelweis University, Tűzoltó Str. 37-47, H1094 Budapest, Hungary
- HUNREN-SE Biophysical Virology Group, Tűzoltó Str. 37-47, H1094 Budapest, Hungary
| | - Levente Herényi
- Department of Biophysics and Radiation Biology, Semmelweis University, Tűzoltó Str. 37-47, H1094 Budapest, Hungary
| | - Gabriella Csík
- Department of Biophysics and Radiation Biology, Semmelweis University, Tűzoltó Str. 37-47, H1094 Budapest, Hungary
| | - Eszter Supala
- Department of Biophysics and Radiation Biology, Semmelweis University, Tűzoltó Str. 37-47, H1094 Budapest, Hungary
| | - Ádám Orosz
- Department of Biophysics and Radiation Biology, Semmelweis University, Tűzoltó Str. 37-47, H1094 Budapest, Hungary
| | - Hedvig Tordai
- Department of Biophysics and Radiation Biology, Semmelweis University, Tűzoltó Str. 37-47, H1094 Budapest, Hungary
| | - Bálint Kiss
- Department of Biophysics and Radiation Biology, Semmelweis University, Tűzoltó Str. 37-47, H1094 Budapest, Hungary
- HUNREN-SE Biophysical Virology Group, Tűzoltó Str. 37-47, H1094 Budapest, Hungary
| | - Miklós Kellermayer
- Department of Biophysics and Radiation Biology, Semmelweis University, Tűzoltó Str. 37-47, H1094 Budapest, Hungary
- HUNREN-SE Biophysical Virology Group, Tűzoltó Str. 37-47, H1094 Budapest, Hungary
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4
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Yang H, Shi X. Torsion affects the calculation of DNA twisting number. Biochem Biophys Res Commun 2024; 710:149856. [PMID: 38583234 DOI: 10.1016/j.bbrc.2024.149856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 03/27/2024] [Indexed: 04/09/2024]
Abstract
The topological properties of DNA have long been a focal point in biophysics. In the 1970s, White proposed that the topology of closed DNA double helix follows White's formula: Lk=Wr+Tw. However, there has been controversy in the calculation of DNA twisting number, partly due to discrepancies in the definition of torsion in differential geometry. In this paper, we delved into a detailed study of torsion, revealing that the calculation of DNA twisting number should use the curve's geodesic torsion. Furthermore, we found that the discrepancy in DNA twisting numbers calculated using different torsion is N. This study elucidated the impact of torsion on the calculation of DNA twisting numbers, aiming to resolve controversies in the calculation of DNA topology and provided accurate computational methods and theoretical foundations for related research.
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Affiliation(s)
- Huimin Yang
- College of Science, Beijing Forestry University, Beijing, 100083, China
| | - Xuguang Shi
- College of Science, Beijing Forestry University, Beijing, 100083, China.
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5
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van der Sleen L, Stevens JA, Marrink SJ, Poolman B, Tych K. Probing the stability and interdomain interactions in the ABC transporter OpuA using single-molecule optical tweezers. Cell Rep 2024; 43:114110. [PMID: 38607912 DOI: 10.1016/j.celrep.2024.114110] [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: 09/01/2023] [Revised: 12/11/2023] [Accepted: 03/28/2024] [Indexed: 04/14/2024] Open
Abstract
Transmembrane transporter proteins are essential for maintaining cellular homeostasis and, as such, are key drug targets. Many transmembrane transporter proteins are known to undergo large structural rearrangements during their functional cycles. Despite the wealth of detailed structural and functional data available for these systems, our understanding of their dynamics and, consequently, how they function is generally limited. We introduce an innovative approach that enables us to directly measure the dynamics and stability of interdomain interactions of transmembrane proteins using optical tweezers. Focusing on the osmoregulatory ATP-binding cassette transporter OpuA from Lactococcus lactis, we examine the mechanical properties and potential interactions of its substrate-binding domains. Our measurements are performed in lipid nanodiscs, providing a native-mimicking environment for the transmembrane protein. The technique provides high spatial and temporal resolution and allows us to study the functionally relevant motions and interdomain interactions of individual transmembrane transporter proteins in real time in a lipid bilayer.
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Affiliation(s)
- Lyan van der Sleen
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| | - Jan A Stevens
- Molecular Dynamics Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands
| | - Siewert J Marrink
- Molecular Dynamics Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands
| | - Bert Poolman
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands.
| | - Kasia Tych
- Chemical Biology Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands.
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6
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Roldán-Piñero C, Luengo-Márquez J, Assenza S, Pérez R. Systematic Comparison of Atomistic Force Fields for the Mechanical Properties of Double-Stranded DNA. J Chem Theory Comput 2024; 20:2261-2272. [PMID: 38411091 PMCID: PMC10938644 DOI: 10.1021/acs.jctc.3c01089] [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: 10/02/2023] [Revised: 02/14/2024] [Accepted: 02/14/2024] [Indexed: 02/28/2024]
Abstract
The response of double-stranded DNA to external mechanical stress plays a central role in its interactions with the protein machinery in the cell. Modern atomistic force fields have been shown to provide highly accurate predictions for the fine structural features of the duplex. In contrast, and despite their pivotal function, less attention has been devoted to the accuracy of the prediction of the elastic parameters. Several reports have addressed the flexibility of double-stranded DNA via all-atom molecular dynamics, yet the collected information is insufficient to have a clear understanding of the relative performance of the various force fields. In this work, we fill this gap by performing a systematic study in which several systems, characterized by different sequence contexts, are simulated with the most popular force fields within the AMBER family, bcs1 and OL15, as well as with CHARMM36. Analysis of our results, together with their comparison with previous work focused on bsc0, allows us to unveil the differences in the predicted rigidity between the newest force fields and suggests a roadmap to test their performance against experiments. In the case of the stretch modulus, we reconcile these differences, showing that a single mapping between sequence-dependent conformation and elasticity via the crookedness parameter captures simultaneously the results of all force fields, supporting the key role of crookedness in the mechanical response of double-stranded DNA.
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Affiliation(s)
- Carlos Roldán-Piñero
- Departamento
de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Juan Luengo-Márquez
- Departamento
de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto
Nicolás Cabrera, Universidad Autónoma
de Madrid, E-28049 Madrid, Spain
| | - Salvatore Assenza
- Departamento
de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto
Nicolás Cabrera, Universidad Autónoma
de Madrid, E-28049 Madrid, Spain
- Condensed
Matter Physics Center (IFIMAC), Universidad
Autónoma de Madrid, E-28049 Madrid, Spain
| | - Rubén Pérez
- Departamento
de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed
Matter Physics Center (IFIMAC), Universidad
Autónoma de Madrid, E-28049 Madrid, Spain
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7
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Zhang Z, Mou X, Zhang Y, He L, Li S. Influence of temperature on bend, twist and twist-bend coupling of dsDNA. Phys Chem Chem Phys 2024; 26:8077-8088. [PMID: 38224130 DOI: 10.1039/d3cp04932a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
The temperature-dependent bend and twist elasticities of dsDNA, as well as their couplings, were explored through all-atom molecular dynamics simulations. Three rotational parameters, tilt, roll, and twist, were employed to assess the bend and twist elasticities through their stiffness matrix. Our analysis indicates that the bend and twist stiffnesses decrease as the temperature rises, primarily owing to entropic influences stemming from thermodynamic fluctuations. Furthermore, the couplings between these rotational parameters also exhibit a decline with increasing temperature, although the roll-twist coupling displays greater strength than the tilt-roll and tilt-twist couplings, attributed to its more robust correction component. We elucidated the influence of temperature on bend and twist elasticities based on the comparisons between various models and existing data.
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Affiliation(s)
- Zihao Zhang
- Department of Physics, Wenzhou University, Wenzhou, 325035, China.
| | - Xuankang Mou
- Department of Physics, Wenzhou University, Wenzhou, 325035, China.
| | - Yahong Zhang
- Department of Physics, Wenzhou University, Wenzhou, 325035, China.
| | - Linli He
- Department of Physics, Wenzhou University, Wenzhou, 325035, China.
| | - Shiben Li
- Department of Physics, Wenzhou University, Wenzhou, 325035, China.
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8
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Bethur E, Guha R, Zhao Z, Katz BB, Ashby PD, Zeng H, Copp SM. Formation and Nanomechanical Properties of Silver-Mediated Guanine DNA Duplexes in Aqueous Solution. ACS NANO 2024; 18:3002-3010. [PMID: 38227309 PMCID: PMC10832345 DOI: 10.1021/acsnano.3c08008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 01/04/2024] [Accepted: 01/10/2024] [Indexed: 01/17/2024]
Abstract
Silver cations can mediate base pairing of guanine (G) DNA oligomers, yielding linear parallel G-Ag+-G duplexes with enhanced stabilities compared to those of canonical DNA duplexes. To enable their use in programmable DNA nanotechnologies, it is critical to understand solution-state formation and the nanomechanical stiffness of G-Ag+-G duplexes. Using temperature-controlled circular dichroism (CD) spectroscopy, we find that heating mixtures of G oligomers and silver salt above 50 °C fully destabilizes G-quadruplex structures and converts oligomers to G-Ag+-G duplexes. Electrospray ionization mass spectrometry supports that G-Ag+-G duplexes form at stoichiometries of 1 Ag+ per base pair, and CD spectroscopy suggests that as the Ag+/base stoichiometry increases further, G-Ag+-G duplexes undergo additional morphological changes. Using liquid-phase atomic force microscopy, we find that this excess Ag+ enables assembly of long fiberlike structures with ∼2.5 nm heights equivalent to a single DNA duplex but with lengths that far exceed a single duplex. Finally, using the conditions established to form single G-Ag+-G duplexes, we use a surface forces apparatus (SFA) to compare the solution-phase stiffness of single G-Ag+-G duplexes with dG-dC Watson-Crick-Franklin duplexes. SFA shows that G-Ag+-G duplexes are 1.3 times stiffer than dG-dC duplexes, confirming gas-phase ion mobility spectrometry measurements and computational predictions. These findings may guide the development of structural DNA nanotechnologies that rely on silver-mediated base pairing.
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Affiliation(s)
- Eshana Bethur
- Department
of Materials Science and Engineering, University
of California, Irvine, California 92697, United States
| | - Rweetuparna Guha
- Department
of Materials Science and Engineering, University
of California, Irvine, California 92697, United States
| | - Ziqian Zhao
- Department
of Chemical and Materials Engineering, University
of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Benjamin B. Katz
- Department
of Chemistry, University of California, Irvine, California 92697, United States
| | - Paul D. Ashby
- Molecular
Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Hongbo Zeng
- Department
of Chemical and Materials Engineering, University
of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Stacy M. Copp
- Department
of Materials Science and Engineering, University
of California, Irvine, California 92697, United States
- Department
of Physics and Astronomy, University of
California, Irvine, California 92697, United States
- Department
of Chemical and Biomolecular Engineering, University of California, Irvine, California 92697, United States
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9
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McCauley MJ, Joshi J, Becker N, Hu Q, Botuyan MV, Rouzina I, Mer G, James Maher L, Williams MC. Quantifying ATP-Independent Nucleosome Chaperone Activity with Single-Molecule Methods. Methods Mol Biol 2024; 2694:29-55. [PMID: 37823998 DOI: 10.1007/978-1-0716-3377-9_2] [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: 10/13/2023]
Abstract
The dynamics of histone-DNA interactions govern chromosome organization and regulates the processes of transcription, replication, and repair. Accurate measurements of the energies and the kinetics of DNA binding to component histones of the nucleosome under a variety of conditions are essential to understand these processes at the molecular level. To accomplish this, we employ three specific single-molecule techniques: force disruption (FD) with optical tweezers, confocal imaging (CI) in a combined fluorescence plus optical trap, and survival probability (SP) measurements of disrupted and reformed nucleosomes. Short arrays of positioned nucleosomes serve as a template for study, facilitating rapid quantification of kinetic parameters. These arrays are then exposed to FACT (FAcilitates Chromatin Transcription), a non-ATP-driven heterodimeric nuclear chaperone known to both disrupt and tether histones during transcription. FACT binding drives off the outer wrap of DNA and destabilizes the histone-DNA interactions of the inner wrap as well. This reorganization is driven by two key domains with distinct function. FD experiments show the SPT16 MD domain stabilizes DNA-histone contacts, while the HMGB box of SSRP1 binds DNA, destabilizing the nucleosome. Surprisingly, CI experiments do not show tethering of disrupted histones, but increased rates of histone release from the DNA. SI experiments resolve this, showing that the two active domains of FACT combine to chaperone nucleosome reassembly after the timely release of force. These combinations of single-molecule approaches show FACT is a true nucleosome catalyst, lowering the barrier to both disruption and reformation.
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Affiliation(s)
| | - Joha Joshi
- Department of Physics, Northeastern University, Boston, MA, USA
| | - Nicole Becker
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
| | - Qi Hu
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
| | - Maria Victoria Botuyan
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
| | - Ioulia Rouzina
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH, USA
| | - Georges Mer
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
| | - L James Maher
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
| | - Mark C Williams
- Department of Physics, Northeastern University, Boston, MA, USA.
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10
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Basov A, Dorohova A, Malyshko V, Moiseev A, Svidlov A, Bezhenar M, Nechipurenko Y, Dzhimak S. Influence of a Single Deuterium Substitution for Protium on the Frequency Generation of Different-Size Bubbles in IFNA17. Int J Mol Sci 2023; 24:12137. [PMID: 37569512 PMCID: PMC10418495 DOI: 10.3390/ijms241512137] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/21/2023] [Accepted: 07/23/2023] [Indexed: 08/13/2023] Open
Abstract
The influence of a single 2H/1H replacement on the frequency generation of different-size bubbles in the human interferon alpha-17 gene (IFNA17) under various energies was studied by a developed algorithm and mathematical modeling without simplifications or averaging. This new approach showed the efficacy of researching DNA bubbles and open states both when all hydrogen bonds in nitrogenous base pairs are protium and after an 2H-substitution. After a single deuterium substitution under specific energies, it was demonstrated that the non-coding region of IFNA17 had a more significant regulatory role in bubble generation in the whole gene than the promoter had. It was revealed that a single deuterium substitution for protium has an influence on the frequency generation of DNA bubbles, which also depends on their size and is always higher for the smaller bubbles under the largest number of the studied energies. Wherein, compared to the natural condition under the same critical value of energy, the bigger raises of the bubble frequency occurrence (maximums) were found for 11-30 base pair (bp) bubbles (higher by 319%), 2-4 bp bubbles (higher by 300%), and 31 bp and over ones (higher by 220%); whereas the most significant reductions of the indicators (minimums) were observed for 11-30 bp bubbles (lower by 43%) and bubbles size over 30 bp (lower by 82%). In this study, we also analyzed the impact of several circumstances on the AT/GC ratio in the formation of DNA bubbles, both under natural conditions and after a single hydrogen isotope exchange. Moreover, based on the obtained data, substantial positive and inverse correlations were revealed between the AT/GC ratio and some factors (energy values, size of DNA bubbles). So, this modeling and variant of the modified algorithm, adapted for researching DNA bubbles, can be useful to study the regulation of replication and transcription in the genes under different isotopic substitutions in the nucleobases.
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Affiliation(s)
- Alexandr Basov
- Department of Fundamental and Clinical Biochemistry, Kuban State Medical University, Krasnodar 350063, Russia; (A.B.); (V.M.)
- Department of Radiophysics and Nanotechnology, Kuban State University, Krasnodar 350040, Russia; (A.D.); (A.S.); (S.D.)
| | - Anna Dorohova
- Department of Radiophysics and Nanotechnology, Kuban State University, Krasnodar 350040, Russia; (A.D.); (A.S.); (S.D.)
- Laboratory of Problems of Stable Isotope Spreading in Living Systems, Federal Research Center of the Southern Scientific Center of the Russian Academy of Sciences, Rostov-on-Don 344006, Russia
| | - Vadim Malyshko
- Department of Fundamental and Clinical Biochemistry, Kuban State Medical University, Krasnodar 350063, Russia; (A.B.); (V.M.)
- Laboratory of Problems of Stable Isotope Spreading in Living Systems, Federal Research Center of the Southern Scientific Center of the Russian Academy of Sciences, Rostov-on-Don 344006, Russia
| | - Arkadii Moiseev
- Scientific Department, Kuban State Agrarian University, Krasnodar 350004, Russia;
| | - Alexandr Svidlov
- Department of Radiophysics and Nanotechnology, Kuban State University, Krasnodar 350040, Russia; (A.D.); (A.S.); (S.D.)
- Laboratory of Problems of Stable Isotope Spreading in Living Systems, Federal Research Center of the Southern Scientific Center of the Russian Academy of Sciences, Rostov-on-Don 344006, Russia
| | - Maria Bezhenar
- Department of Function Theory, Kuban State University, Krasnodar 350040, Russia;
| | - Yury Nechipurenko
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia
| | - Stepan Dzhimak
- Department of Radiophysics and Nanotechnology, Kuban State University, Krasnodar 350040, Russia; (A.D.); (A.S.); (S.D.)
- Laboratory of Problems of Stable Isotope Spreading in Living Systems, Federal Research Center of the Southern Scientific Center of the Russian Academy of Sciences, Rostov-on-Don 344006, Russia
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11
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Magazzù A, Marcuello C. Investigation of Soft Matter Nanomechanics by Atomic Force Microscopy and Optical Tweezers: A Comprehensive Review. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:963. [PMID: 36985857 PMCID: PMC10053849 DOI: 10.3390/nano13060963] [Citation(s) in RCA: 43] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 02/28/2023] [Accepted: 03/02/2023] [Indexed: 05/17/2023]
Abstract
Soft matter exhibits a multitude of intrinsic physico-chemical attributes. Their mechanical properties are crucial characteristics to define their performance. In this context, the rigidity of these systems under exerted load forces is covered by the field of biomechanics. Moreover, cellular transduction processes which are involved in health and disease conditions are significantly affected by exogenous biomechanical actions. In this framework, atomic force microscopy (AFM) and optical tweezers (OT) can play an important role to determine the biomechanical parameters of the investigated systems at the single-molecule level. This review aims to fully comprehend the interplay between mechanical forces and soft matter systems. In particular, we outline the capabilities of AFM and OT compared to other classical bulk techniques to determine nanomechanical parameters such as Young's modulus. We also provide some recent examples of nanomechanical measurements performed using AFM and OT in hydrogels, biopolymers and cellular systems, among others. We expect the present manuscript will aid potential readers and stakeholders to fully understand the potential applications of AFM and OT to soft matter systems.
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Affiliation(s)
- Alessandro Magazzù
- CNR-IPCF, Istituto per i Processi Chimico-Fisici, 98158 Mesina, Italy
- NLHT-Lab, Department of Physics, University of Calabria, 87036 Rende, Italy
| | - Carlos Marcuello
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
- Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza, Spain
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12
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Zhang Y, He L, Li S. Temperature dependence of DNA elasticity: An all-atom molecular dynamics simulation study. J Chem Phys 2023; 158:094902. [PMID: 36889965 DOI: 10.1063/5.0138940] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
We used all-atom molecular dynamics simulation to investigate the elastic properties of double-stranded DNA (dsDNA). We focused on the influences of temperature on the stretch, bend, and twist elasticities, as well as the twist-stretch coupling, of the dsDNA over a wide range of temperature. The results showed that the bending and twist persistence lengths, together with the stretch and twist moduli, decrease linearly with temperature. However, the twist-stretch coupling behaves in a positive correction and enhances as the temperature increases. The potential mechanisms of how temperature affects dsDNA elasticity and coupling were investigated by using the trajectories from atomistic simulation, in which thermal fluctuations in structural parameters were analyzed in detail. We analyzed the simulation results by comparing them with previous simulation and experimental data, which are in good agreement. The prediction about the temperature dependence of dsDNA elastic properties provides a deeper understanding of DNA elasticities in biological environments and potentially helps in the further development of DNA nanotechnology.
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Affiliation(s)
- Yahong Zhang
- Department of Physics, Wenzhou University, Wenzhou, Zhejiang 325035, China
| | - Linli He
- Department of Physics, Wenzhou University, Wenzhou, Zhejiang 325035, China
| | - Shiben Li
- Department of Physics, Wenzhou University, Wenzhou, Zhejiang 325035, China
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13
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Liu J, Le S, Yao M, Huang W, Tio Z, Zhou Y, Yan J. Tension Gauge Tethers as Tension Threshold and Duration Sensors. ACS Sens 2023; 8:704-711. [PMID: 36731861 PMCID: PMC9973368 DOI: 10.1021/acssensors.2c02218] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 01/26/2023] [Indexed: 02/04/2023]
Abstract
Mechanotransduction, the process by which cells respond to tension transmitted through various supramolecular linkages, is important for understanding cellular behavior. Tension gauge tethers (TGTs), short fragments of double-stranded DNA that irreversibly break under shear-stretch conditions, have been used in live cell experiments to study mechanotransduction. However, our current understanding of TGTs' mechanical responses is limited, which limits the information that can be gleaned from experimental observations. In this study, we quantified the tension-dependent lifetime of TGTs to better understand their mechanical stability under various physiologically relevant stretching conditions. This work has broad applications for using TGTs as tension threshold and duration sensors and also suggests the need to revisit previous interpretations of experimental observations.
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Affiliation(s)
- Jingzhun Liu
- Mechanobiology
Institute, National University of Singapore, 117411Singapore
| | - Shimin Le
- Department
of Physics, Xiamen University, Xiamen361005, People’s Repbulic of China
| | - Mingxi Yao
- Department
of Biomedical Engineering, Southern University
of Science and Technology, Shenzhen518055, People’s Repbulic of China
| | - Wenmao Huang
- Department
of Physics, National University of Singapore, 117546Singapore
| | - Zhikai Tio
- Department
of Chemical and Biomolecular Engineering, National University of Singapore, 117585Singapore
| | - Yu Zhou
- Mechanobiology
Institute, National University of Singapore, 117411Singapore
| | - Jie Yan
- Mechanobiology
Institute, National University of Singapore, 117411Singapore
- Department
of Physics, National University of Singapore, 117546Singapore
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14
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Florio G, Puglisi G. A predictive model for the thermomechanical melting transition of double stranded DNA. Acta Biomater 2023; 157:225-235. [PMID: 36450304 DOI: 10.1016/j.actbio.2022.11.046] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 10/24/2022] [Accepted: 11/21/2022] [Indexed: 11/30/2022]
Abstract
By extending the classical Peyrard-Bishop model, we are able to obtain a fully analytical description for the mechanical response of DNA under stretching at variable values of temperature, number of base pairs and intrachains and interchains bonds stiffness. In order to compare elasticity and temperature effects, we first analyze the system in the zero temperature mechanical limit, important to describe several experimental effects including possible hysteresis. We then analyze temperature effects in the framework of equilibrium Statistical Mechanics. In particular, we obtain an analytical expression for the temperature-dependent melting force and unzipping assigned displacement in the thermodynamical limit, also depending on the relative stability of intra vs. inter molecular bonds. Such results coincide with the purely mechanical model in the limit of zero temperature and with the denaturation temperature that we obtain with the classical transfer integral method. Based on our analytical results, we obtain explicitly phase diagrams and cooperativity parameters, where also discreteness effect can be accounted for. The obtained results are successfully applied in reproducing the thermomechanical experimental melting of DNA and the response of DNA hairpins. Due to the generality of the model, exemplified in the proposed analysis of both overstretching and unzipping experiments, we argue that the proposed approach can be extended to other thermomechanically induced molecular melting phenomena. STATEMENT OF SIGNIFICANCE: We obtain a fully analytical description of the complex wiggly energy landscape of two stranded macromolecules under unzipping loading. Based on Equilibrium Statistical Mechanics, we describe the combined thermomechanical effects and the melting transition of double stranded molecules such as nucleic acids. This is proved by quantitatively predicting the experimental behavior of both melting of DNA and DNA hairpins opening. While analytical results have been previously attained under special conditions on the relative stiffness of the covalent vs. non-covalent bonds of the base pairs, our model is completely general in this respect, thus representing a tool in the perspective of the design at the molecular scale. We show that the obtained model can be fully inscribed in the theory of phase transitions giving a new interpretation of the thermomechanical behavior of double stranded molecules.
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Affiliation(s)
- Giuseppe Florio
- Politecnico di Bari, Dipartimento di Ing. Civile, Ambientale, del Territorio, Edile e di Chimica, Via Re David 200, Bari 70126, Italy; INFN, Sezione di Bari, I-70126, Italy.
| | - Giuseppe Puglisi
- Politecnico di Bari, Dipartimento di Ing. Civile, Ambientale, del Territorio, Edile e di Chimica, Via Re David 200, Bari 70126, Italy.
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15
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McCauley MJ, Morse M, Becker N, Hu Q, Botuyan MV, Navarrete E, Huo R, Muthurajan UM, Rouzina I, Luger K, Mer G, Maher LJ, Williams MC. Human FACT subunits coordinate to catalyze both disassembly and reassembly of nucleosomes. Cell Rep 2022; 41:111858. [PMID: 36577379 PMCID: PMC9807050 DOI: 10.1016/j.celrep.2022.111858] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 10/06/2022] [Accepted: 11/30/2022] [Indexed: 12/28/2022] Open
Abstract
The histone chaperone FACT (facilitates chromatin transcription) enhances transcription in eukaryotic cells, targeting DNA-protein interactions. FACT, a heterodimer in humans, comprises SPT16 and SSRP1 subunits. We measure nucleosome stability and dynamics in the presence of FACT and critical component domains. Optical tweezers quantify FACT/subdomain binding to nucleosomes, displacing the outer wrap of DNA, disrupting direct DNA-histone (core site) interactions, altering the energy landscape of unwrapping, and increasing the kinetics of DNA-histone disruption. Atomic force microscopy reveals nucleosome remodeling, while single-molecule fluorescence quantifies kinetics of histone loss for disrupted nucleosomes, a process accelerated by FACT. Furthermore, two isolated domains exhibit contradictory functions; while the SSRP1 HMGB domain displaces DNA, SPT16 MD/CTD stabilizes DNA-H2A/H2B dimer interactions. However, only intact FACT tethers disrupted DNA to the histones and supports rapid nucleosome reformation over several cycles of force disruption/release. These results demonstrate that key FACT domains combine to catalyze both nucleosome disassembly and reassembly.
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Affiliation(s)
| | - Michael Morse
- Department of Physics, Northeastern University, Boston, MA, USA
| | - Nicole Becker
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
| | - Qi Hu
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
| | - Maria Victoria Botuyan
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
| | - Emily Navarrete
- Department of Physics, Northeastern University, Boston, MA, USA
| | - Ran Huo
- Department of Physics, Northeastern University, Boston, MA, USA
| | - Uma M. Muthurajan
- Department of Biochemistry, University of Colorado, Boulder, CO, USA
| | - Ioulia Rouzina
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH 43210, USA
| | - Karolin Luger
- Department of Biochemistry, University of Colorado, Boulder, CO, USA,Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Georges Mer
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
| | - L. James Maher
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
| | - Mark C. Williams
- Department of Physics, Northeastern University, Boston, MA, USA,Lead contact,Correspondence:
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16
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Singh A, Maity A, Singh N. Structure and Dynamics of dsDNA in Cell-like Environments. ENTROPY (BASEL, SWITZERLAND) 2022; 24:1587. [PMID: 36359677 PMCID: PMC9689892 DOI: 10.3390/e24111587] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 10/28/2022] [Accepted: 10/31/2022] [Indexed: 06/01/2023]
Abstract
Deoxyribonucleic acid (DNA) is a fundamental biomolecule for correct cellular functioning and regulation of biological processes. DNA's structure is dynamic and has the ability to adopt a variety of structural conformations in addition to its most widely known double-stranded DNA (dsDNA) helix structure. Stability and structural dynamics of dsDNA play an important role in molecular biology. In vivo, DNA molecules are folded in a tightly confined space, such as a cell chamber or a channel, and are highly dense in solution; their conformational properties are restricted, which affects their thermodynamics and mechanical properties. There are also many technical medical purposes for which DNA is placed in a confined space, such as gene therapy, DNA encapsulation, DNA mapping, etc. Physiological conditions and the nature of confined spaces have a significant influence on the opening or denaturation of DNA base pairs. In this review, we summarize the progress of research on the stability and dynamics of dsDNA in cell-like environments and discuss current challenges and future directions. We include studies on various thermal and mechanical properties of dsDNA in ionic solutions, molecular crowded environments, and confined spaces. By providing a better understanding of melting and unzipping of dsDNA in different environments, this review provides valuable guidelines for predicting DNA thermodynamic quantities and for designing DNA/RNA nanostructures.
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17
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Rico-Pasto M, Ritort F. Temperature-dependent elastic properties of DNA. BIOPHYSICAL REPORTS 2022; 2:100067. [PMID: 36425333 PMCID: PMC9680767 DOI: 10.1016/j.bpr.2022.100067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 07/20/2022] [Indexed: 06/02/2023]
Abstract
Knowledge of the elastic properties, e.g., the persistence length or interphosphate distance, of single-stranded (ss) and double-stranded (ds) DNA under different experimental conditions is critical to characterizing molecular reactions studied with single-molecule techniques. While previous experiments have addressed the dependence of the elastic parameters upon varying ionic strength and contour length, temperature-dependent effects are less studied. Here, we examine the temperature-dependent elasticity of ssDNA and dsDNA in the range 5°C-50°C using a temperature-jump optical trap. We find a temperature softening for dsDNA and a temperature stiffening for ssDNA. Our results highlight the need for a general theory explaining the phenomenology observed.
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Affiliation(s)
- Marc Rico-Pasto
- Small Biosystems Lab, Condensed Matter Physics Department, University of Barcelona, Barcelona, Spain
| | - Felix Ritort
- Small Biosystems Lab, Condensed Matter Physics Department, University of Barcelona, Barcelona, Spain
- Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, Barcelona, Spain
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18
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Zhang Y, Yan M, Huang T, Wang X. Understanding the Structural Elasticity of RNA and DNA: All‐Atom Molecular Dynamics. ADVANCED THEORY AND SIMULATIONS 2022. [DOI: 10.1002/adts.202200534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Yingtong Zhang
- Department of Physics Wenzhou University Wenzhou 325035 China
| | - Miao Yan
- Department of Physics Wenzhou University Wenzhou 325035 China
| | - Tingting Huang
- Department of Mechanical Engineering Shanghai Techanical Institute of Electronics and Information Shanghai 201411 China
| | - Xianghong Wang
- Department of Physics Wenzhou University Wenzhou 325035 China
- Department of Mechanical Engineering Shanghai Techanical Institute of Electronics and Information Shanghai 201411 China
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19
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Cruz-León S, Vanderlinden W, Müller P, Forster T, Staudt G, Lin YY, Lipfert J, Schwierz N. Twisting DNA by salt. Nucleic Acids Res 2022; 50:5726-5738. [PMID: 35640616 PMCID: PMC9177979 DOI: 10.1093/nar/gkac445] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 05/06/2022] [Accepted: 05/10/2022] [Indexed: 12/11/2022] Open
Abstract
The structure and properties of DNA depend on the environment, in particular the ion atmosphere. Here, we investigate how DNA twist -one of the central properties of DNA- changes with concentration and identity of the surrounding ions. To resolve how cations influence the twist, we combine single-molecule magnetic tweezer experiments and extensive all-atom molecular dynamics simulations. Two interconnected trends are observed for monovalent alkali and divalent alkaline earth cations. First, DNA twist increases monotonously with increasing concentration for all ions investigated. Second, for a given salt concentration, DNA twist strongly depends on cation identity. At 100 mM concentration, DNA twist increases as Na+ < K+ < Rb+ < Ba2+ < Li+ ≈ Cs+ < Sr2+ < Mg2+ < Ca2+. Our molecular dynamics simulations reveal that preferential binding of the cations to the DNA backbone or the nucleobases has opposing effects on DNA twist and provides the microscopic explanation of the observed ion specificity. However, the simulations also reveal shortcomings of existing force field parameters for Cs+ and Sr2+. The comprehensive view gained from our combined approach provides a foundation for understanding and predicting cation-induced structural changes both in nature and in DNA nanotechnology.
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Affiliation(s)
- Sergio Cruz-León
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt am Main, Germany
| | - Willem Vanderlinden
- Department of Physics and Center for Nanoscience (CeNS), LMU Munich, Amalienstr. 54, 80799 Munich, Germany
| | - Peter Müller
- Department of Physics and Center for Nanoscience (CeNS), LMU Munich, Amalienstr. 54, 80799 Munich, Germany
| | - Tobias Forster
- Department of Physics and Center for Nanoscience (CeNS), LMU Munich, Amalienstr. 54, 80799 Munich, Germany
| | - Georgina Staudt
- Department of Physics and Center for Nanoscience (CeNS), LMU Munich, Amalienstr. 54, 80799 Munich, Germany
| | - Yi-Yun Lin
- Department of Physics and Center for Nanoscience (CeNS), LMU Munich, Amalienstr. 54, 80799 Munich, Germany
| | - Jan Lipfert
- Department of Physics and Center for Nanoscience (CeNS), LMU Munich, Amalienstr. 54, 80799 Munich, Germany
| | - Nadine Schwierz
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt am Main, Germany
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20
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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.
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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
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21
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Assenza S, Pérez R. Accurate Sequence-Dependent Coarse-Grained Model for Conformational and Elastic Properties of Double-Stranded DNA. J Chem Theory Comput 2022; 18:3239-3256. [PMID: 35394775 PMCID: PMC9097290 DOI: 10.1021/acs.jctc.2c00138] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
![]()
We introduce MADna,
a sequence-dependent coarse-grained model of
double-stranded DNA (dsDNA), where each nucleotide is described by
three beads localized at the sugar, at the base moiety, and at the
phosphate group, respectively. The sequence dependence is included
by considering a step-dependent parametrization of the bonded interactions,
which are tuned in order to reproduce the values of key observables
obtained from exhaustive atomistic simulations from the literature.
The predictions of the model are benchmarked against an independent
set of all-atom simulations, showing that it captures with high fidelity
the sequence dependence of conformational and elastic features beyond
the single step considered in its formulation. A remarkably good agreement
with experiments is found for both sequence-averaged and sequence-dependent
conformational and elastic features, including the stretching and
torsion moduli, the twist–stretch and twist–bend couplings,
the persistence length, and the helical pitch. Overall, for the inspected
quantities, the model has a precision comparable to atomistic simulations,
hence providing a reliable coarse-grained description for the rationalization
of single-molecule experiments and the study of cellular processes
involving dsDNA. Owing to the simplicity of its formulation, MADna
can be straightforwardly included in common simulation engines. Particularly,
an implementation of the model in LAMMPS is made available on an online
repository to ease its usage within the DNA research community.
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22
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Zhang C, Tian F, Lu Y, Yuan B, Tan ZJ, Zhang XH, Dai L. Twist-diameter coupling drives DNA twist changes with salt and temperature. SCIENCE ADVANCES 2022; 8:eabn1384. [PMID: 35319990 PMCID: PMC8942373 DOI: 10.1126/sciadv.abn1384] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/31/2022] [Indexed: 06/14/2023]
Abstract
DNA deformations upon environmental changes, e.g., salt and temperature, play crucial roles in many biological processes and material applications. Here, our magnetic tweezers experiments observed that the increase in NaCl, KCl, or RbCl concentration leads to substantial DNA overwinding. Our simulations and theoretical calculation quantitatively explain the salt-induced twist change through the mechanism: More salt enhances the screening of interstrand electrostatic repulsion and hence reduces DNA diameter, which is transduced to twist increase through twist-diameter coupling. We determined that the coupling constant is 4.5 ± 0.8 kBT/(degrees∙nm) for one base pair. The coupling comes from the restraint of the contour length of DNA backbone. On the basis of this coupling constant and diameter-dependent DNA conformational entropy, we predict the temperature dependence of DNA twist Δωbp/ΔT ≈ -0.01 degree/°C, which agrees with our and previous experimental results. Our analysis suggests that twist-diameter coupling is a common driving force for salt- and temperature-induced DNA twist changes.
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Affiliation(s)
- Chen Zhang
- College of Life Sciences, The Institute for Advanced Studies, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, Wuhan University, Wuhan 430072, China
| | - Fujia Tian
- Department of Physics, City University of Hong Kong, Hong Kong 999077, China
| | - Ying Lu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Bing Yuan
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Zhi-Jie Tan
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Xing-Hua Zhang
- College of Life Sciences, The Institute for Advanced Studies, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, Wuhan University, Wuhan 430072, China
| | - Liang Dai
- Department of Physics, City University of Hong Kong, Hong Kong 999077, China
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China
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23
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Moon HM, Park JS, Lee IB, Kang YI, Jung HJ, An D, Shin Y, Kim MJ, Kim HI, Song JJ, Kim J, Lee NK, Hong SC. Cisplatin fastens chromatin irreversibly even at a high chloride concentration. Nucleic Acids Res 2021; 49:12035-12047. [PMID: 34865121 PMCID: PMC8643659 DOI: 10.1093/nar/gkab922] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 09/12/2021] [Accepted: 09/28/2021] [Indexed: 12/17/2022] Open
Abstract
Cisplatin is one of the most potent anti-cancer drugs developed so far. Recent studies highlighted several intriguing roles of histones in cisplatin's anti-cancer effect. Thus, the effect of nucleosome formation should be considered to give a better account of the anti-cancer effect of cisplatin. Here we investigated this important issue via single-molecule measurements. Surprisingly, the reduced activity of cisplatin under [NaCl] = 180 mM, corresponding to the total concentration of cellular ionic species, is still sufficient to impair the integrity of a nucleosome by retaining its condensed structure firmly, even against severe mechanical and chemical disturbances. Our finding suggests that such cisplatin-induced fastening of chromatin can inhibit nucleosome remodelling required for normal biological functions. The in vitro chromatin transcription assay indeed revealed that the transcription activity was effectively suppressed in the presence of cisplatin. Our direct physical measurements on cisplatin-nucleosome adducts suggest that the formation of such adducts be the key to the anti-cancer effect by cisplatin.
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Affiliation(s)
- Hyeon-Min Moon
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, Seoul 02841, Korea.,Department of Physics, Korea University, Seoul 02841, Korea
| | - Jin-Sung Park
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, Seoul 02841, Korea
| | - Il-Buem Lee
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, Seoul 02841, Korea.,Department of Physics, Korea University, Seoul 02841, Korea
| | - Young-Im Kang
- Department of Physics, Korea University, Seoul 02841, Korea
| | - Hae Jun Jung
- Department of Physics, Korea University, Seoul 02841, Korea
| | - Dongju An
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Yumi Shin
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Min Ji Kim
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Hugh I Kim
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Ji-Joon Song
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Jaehoon Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Nam-Kyung Lee
- Department of Physics, Sejong University, Seoul 05006, Korea
| | - Seok-Cheol Hong
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, Seoul 02841, Korea.,Department of Physics, Korea University, Seoul 02841, Korea
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24
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Kolesnikov ES, Gushchin IY, Zhilyaev PA, Onufriev AV. Similarities and Differences between Na + and K + Distributions around DNA Obtained with Three Popular Water Models. J Chem Theory Comput 2021; 17:7246-7259. [PMID: 34633813 DOI: 10.1021/acs.jctc.1c00332] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have compared distributions of sodium and potassium ions around double-stranded DNA, simulated using fixed charge SPC/E, TIP3P, and OPC water models and the Joung/Cheatham (J/C) ion parameter set, as well as the Li/Merz HFE 6-12 (L/M HFE) ion parameters for OPC water. In all the simulations, the ion distributions are in qualitative agreement with Manning's condensation theory and the Debye-Hückel theory, where expected. In agreement with experiment, binding affinity of monovalent ions to DNA does not depend on ion type in every solvent model. However, behavior of deeply bound ions, including ions bound to specific sites, depends strongly on the solvent model. In particular, the number of potassium ions in the minor groove of AT-tracts differs at least 3-fold between the solvent models tested. The number of sodium ions associated with the DNA agrees quantitatively with the experiment for the OPC water model, followed closely by TIP3P+J/C; the largest deviation from the experiment, ∼10%, is seen for SPC/E+J/C. On the other hand, SPC/E+J/C model is most consistent (67%) with the experimental potassium binding sites, followed by OPC+J/C (60%), TIP3P+J/C (53%), and OPC+L/M HFE (27%). The use of NBFIX correction with TIP3P+J/C improves its consistency with the experiment. In summary, the choice of the solvent model matters little for simulating the diffuse atmosphere of sodium and potassium ions around DNA, but ion distributions become increasingly sensitive to the solvent model near the helical axis. We offer an explanation for these trends. There is no single gold standard solvent model, although OPC water with J/C ions or TIP3P with J/C + NBFIX may offer an imperfect compromise for practical simulations of ionic atmospheres around DNA.
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Affiliation(s)
- Egor S Kolesnikov
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny 141700, Russia
| | - Ivan Yu Gushchin
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny 141700, Russia
| | - Petr A Zhilyaev
- Center for Design, Manufacturing and Materials, Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, bld. 1, Moscow 121205, Russia
| | - Alexey V Onufriev
- Department of Computer Science, Virginia Tech, Blacksburg 24061-0131, United States.,Department of Physics, Virginia Tech, Blacksburg 24061-0131, United States.,Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg 24061-0131, United States
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25
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Abstract
DNA dynamics can only be understood by taking into account its complex mechanical behavior at different length scales. At the micrometer level, the mechanical properties of single DNA molecules have been well-characterized by polymer models and are commonly quantified by a persistence length of 50 nm (~150 bp). However, at the base pair level (~3.4 Å), the dynamics of DNA involves complex molecular mechanisms that are still being deciphered. Here, we review recent single-molecule experiments and molecular dynamics simulations that are providing novel insights into DNA mechanics from such a molecular perspective. We first discuss recent findings on sequence-dependent DNA mechanical properties, including sequences that resist mechanical stress and sequences that can accommodate strong deformations. We then comment on the intricate effects of cytosine methylation and DNA mismatches on DNA mechanics. Finally, we review recently reported differences in the mechanical properties of DNA and double-stranded RNA, the other double-helical carrier of genetic information. A thorough examination of the recent single-molecule literature permits establishing a set of general 'rules' that reasonably explain the mechanics of nucleic acids at the base pair level. These simple rules offer an improved description of certain biological systems and might serve as valuable guidelines for future design of DNA and RNA nanostructures.
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Corsetti S, Dholakia K. Optical manipulation: advances for biophotonics in the 21st century. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210127-PER. [PMID: 34235899 PMCID: PMC8262092 DOI: 10.1117/1.jbo.26.7.070602] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 06/17/2021] [Indexed: 05/10/2023]
Abstract
SIGNIFICANCE Optical trapping is a technique capable of applying minute forces that has been applied to studies spanning single molecules up to microorganisms. AIM The goal of this perspective is to highlight some of the main advances in the last decade in this field that are pertinent for a biomedical audience. APPROACH First, the direct determination of forces in optical tweezers and the combination of optical and acoustic traps, which allows studies across different length scales, are discussed. Then, a review of the progress made in the direct trapping of both single-molecules, and even single-viruses, and single cells with optical forces is outlined. Lastly, future directions for this methodology in biophotonics are discussed. RESULTS In the 21st century, optical manipulation has expanded its unique capabilities, enabling not only a more detailed study of single molecules and single cells but also of more complex living systems, giving us further insights into important biological activities. CONCLUSIONS Optical forces have played a large role in the biomedical landscape leading to exceptional new biological breakthroughs. The continuous advances in the world of optical trapping will certainly lead to further exploitation, including exciting in-vivo experiments.
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Affiliation(s)
- Stella Corsetti
- University of St Andrews, SUPA, School of Physics and Astronomy, St. Andrews, United Kingdom
- Address all correspondence to Stella Corsetti,
| | - Kishan Dholakia
- University of St Andrews, SUPA, School of Physics and Astronomy, St. Andrews, United Kingdom
- University of Adelaide, School of Biological Sciences, Adelaide, South Australia, Australia
- Yonsei University, College of Science, Department of Physics, Seoul, Republic of Korea
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27
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Naskar S, Maiti PK. Mechanical properties of DNA and DNA nanostructures: comparison of atomistic, Martini and oxDNA models. J Mater Chem B 2021; 9:5102-5113. [PMID: 34127998 DOI: 10.1039/d0tb02970j] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The flexibility and stiffness of small DNA molecules play a fundamental role ranging from several biophysical processes to nano-technological applications. Here, we estimate the mechanical properties of short double-stranded DNA (dsDNA) with lengths ranging from 12 base-pairs (bp) to 56 bp, paranemic crossover (PX) DNA and hexagonal DNA nanotubes (DNTs) using two widely used coarse-grained models - Martini and oxDNA. To calculate the persistence length (Lp) and the stretch modulus (γ) of the dsDNA, we incorporate the worm-like chain and elastic rod model, while for the DNTs, we implement our previously developed theoretical framework. We compare and contrast all of the results with previously reported all-atom molecular dynamics (MD) simulations and experimental results. The mechanical properties of dsDNA (Lp ∼ 50 nm, γ ∼ 800-1500 pN), PX DNA (γ ∼ 1600-2000 pN) and DNTs (Lp ∼ 1-10 μm, γ ∼ 6000-8000 pN) estimated using the Martini soft elastic network and oxDNA are in very good agreement with the all-atom MD and experimental values, while the stiff elastic network Martini reproduces values of Lp and γ which are an order of magnitude higher. The high flexibility of small dsDNA is also depicted in our calculations. However, Martini models proved inadequate to capture the salt concentration effects on the mechanical properties with increasing salt molarity. oxDNA captures the salt concentration effect on the small dsDNA mechanics. But it is found to be ineffective for reproducing the salt-dependent mechanical properties of DNTs. Also, unlike Martini, the time evolved PX DNA and DNT structures from the oxDNA models are comparable to the all-atom MD simulated structures. Our findings provide a route to study the mechanical properties of DNA and DNA based nanostructures with increased time and length scales and has a remarkable implication in the context of DNA nanotechnology.
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Affiliation(s)
- Supriyo Naskar
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore, 560012, India.
| | - Prabal K Maiti
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore, 560012, India.
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28
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Majumdar D. Elasticity of a DNA chain dotted with bubbles under force. Phys Rev E 2021; 103:052412. [PMID: 34134228 DOI: 10.1103/physreve.103.052412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 05/04/2021] [Indexed: 11/07/2022]
Abstract
The flexibility and the extension along the direction of the force are shown to be related to the bubble number fluctuation and the average number of bubbles, respectively, when the strands of the DNA are subjected to a force along the same direction, here called a stretching force. The force-temperature phase diagram shows the existence of a tricritical point, where the first-order force-induced zipping transition becomes continuous. On the other hand, when the forces are being applied in opposite directions, here called an unzipping force, the transition remains first order, with the possibility of vanishing of the low-temperature reentrant phase for a semiflexible DNA. Moreover, we found that the bulk elasticity changes only if an external force penetrates the bound phase and affects the bubble states.
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Affiliation(s)
- Debjyoti Majumdar
- Institute of Physics, Bhubaneswar, Odisha 751005, India and Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
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Mo Y, Fizari M, Koharchik K, Smith DE. Determining Trap Compliances, Microsphere Size Variations, and Response Linearities in Single DNA Molecule Elasticity Measurements with Optical Tweezers. Front Mol Biosci 2021; 8:605102. [PMID: 33829038 PMCID: PMC8019724 DOI: 10.3389/fmolb.2021.605102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 02/05/2021] [Indexed: 11/25/2022] Open
Abstract
We previously introduced the use of DNA molecules for calibration of biophysical force and displacement measurements with optical tweezers. Force and length scale factors can be determined from measurements of DNA stretching. Trap compliance can be determined by fitting the data to a nonlinear DNA elasticity model, however, noise/drift/offsets in the measurement can affect the reliability of this determination. Here we demonstrate a more robust method that uses a linear approximation for DNA elasticity applied to high force range (25-45 pN) data. We show that this method can be used to assess how small variations in microsphere sizes affect DNA length measurements and demonstrate methods for correcting for these errors. We further show that these measurements can be used to check assumed linearities of system responses. Finally, we demonstrate methods combining microsphere imaging and DNA stretching to check the compliance and positioning of individual traps.
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Affiliation(s)
| | | | | | - Douglas E. Smith
- Department of Physics, University of California San Diego, La Jolla, CA, United States
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30
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Direct unfolding of RuvA-HJ complex at the single-molecule level. Biophys J 2021; 120:1894-1902. [PMID: 33737156 DOI: 10.1016/j.bpj.2021.03.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 03/03/2021] [Accepted: 03/09/2021] [Indexed: 11/20/2022] Open
Abstract
The repair of double-stranded DNA breaks via homologous recombination involves a four-way cross-strand intermediate known as Holliday junction (HJ), which is recognized, processed, and resolved by a specific set of proteins. RuvA, a prokaryotic HJ-binding protein, is known to stabilize the square-planar conformation of the HJ, which is otherwise a short-lived intermediate. Despite much progress being made regarding the molecular mechanism of RuvA-HJ interactions, the mechanochemical aspect of this protein-HJ complex is yet to be investigated. Here, we employed an optical-tweezers-based, single-molecule manipulation assay to detect the formation of RuvA-HJ complex and determined its mechanical and thermodynamic properties in a manner that would be impossible with traditional ensemble techniques. We found that the binding of RuvA increases the unfolding force (Funfold) of the HJ by ∼2-fold. Compared with the ΔGunfold of the HJ alone (54 ± 13 kcal/mol), the increased free energy of the RuvA-HJ complex (101 ± 20 kcal/mol) demonstrates that the RuvA protein stabilizes HJs. Interestingly, the protein remains bound to the mechanically melted HJ, facilitating its refolding at an unusually high force when the stretched DNA molecule is relaxed. These results suggest that the RuvA protein not only stabilizes the HJs but also induces refolding of the HJs. The single-molecule platform that we employed here for studying the RuvA-HJ interaction is broadly applicable to study other HJ-binding proteins involved in the critical DNA repair process.
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31
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Vishnubhotla R, Montgomery CB, Steffens KL, Semancik S. Conformational Changes of Immobilized Polythymine due to External Stressors Studied with Temperature-Controlled Electrochemical Microdevices. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:2607-2618. [PMID: 33595321 PMCID: PMC9278808 DOI: 10.1021/acs.langmuir.0c03219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Conformational changes of single-stranded DNA (ssDNA) play an important role in a DNA strand's ability to bind to target ligands. A variety of factors can influence conformation, including temperature, ionic strength, pH, buffer cation valency, strand length, and sequence. To better understand the effects of these factors on immobilized DNA structures, we employ temperature-controlled electrochemical microsensors to study the effects of salt concentration and temperature variation on the conformation and motion of polythymine (polyT) strands of varying lengths (10, 20, 50 nucleotides). PolyT strands were tethered to a gold working electrode at the proximal end through a thiol linker via covalent bonding between the Au electrode and sulfur link, which can tend to decompose between a temperature range of 60 and 90 °C. The strands were also modified with an electrochemically active methylene blue (MB) moiety at the distal end. Electron transfer (eT) was measured by square wave voltammetry (SWV) and used to infer information pertaining to the average distance between the MB and the working electrode. We observe changes in DNA flexibility due to varying ionic strength, while the effects of increased DNA thermal motion are tracked for elevated temperatures. This work elucidates the behavior of ssDNA in the presence of a phosphate-buffered saline at NaCl concentrations ranging from 20 to 1000 mmol/L through a temperature range of 10-50 °C in 1° increments, well below the decomposition temperature range. The results lay the groundwork for studies on more complex DNA strands in conjunction with different chemical and physical conditions.
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32
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Marin-Gonzalez A, Pastrana CL, Bocanegra R, Martín-González A, Vilhena JG, Pérez R, Ibarra B, Aicart-Ramos C, Moreno-Herrero F. Understanding the paradoxical mechanical response of in-phase A-tracts at different force regimes. Nucleic Acids Res 2020; 48:5024-5036. [PMID: 32282908 PMCID: PMC7229863 DOI: 10.1093/nar/gkaa225] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/23/2020] [Accepted: 03/25/2020] [Indexed: 12/31/2022] Open
Abstract
A-tracts are A:T rich DNA sequences that exhibit unique structural and mechanical properties associated with several functions in vivo. The crystallographic structure of A-tracts has been well characterized. However, the mechanical properties of these sequences is controversial and their response to force remains unexplored. Here, we rationalize the mechanical properties of in-phase A-tracts present in the Caenorhabditis elegans genome over a wide range of external forces, using single-molecule experiments and theoretical polymer models. Atomic Force Microscopy imaging shows that A-tracts induce long-range (∼200 nm) bending, which originates from an intrinsically bent structure rather than from larger bending flexibility. These data are well described with a theoretical model based on the worm-like chain model that includes intrinsic bending. Magnetic tweezers experiments show that the mechanical response of A-tracts and arbitrary DNA sequences have a similar dependence with monovalent salt supporting that the observed A-tract bend is intrinsic to the sequence. Optical tweezers experiments reveal a high stretch modulus of the A-tract sequences in the enthalpic regime. Our work rationalizes the complex multiscale flexibility of A-tracts, providing a physical basis for the versatile character of these sequences inside the cell.
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Affiliation(s)
- Alberto Marin-Gonzalez
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Cantoblanco, Madrid, Spain
| | - Cesar L Pastrana
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Cantoblanco, Madrid, Spain
| | - Rebeca Bocanegra
- IMDEA Nanociencia, C/Faraday 9, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain
| | - Alejandro Martín-González
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Cantoblanco, Madrid, Spain
| | - J G Vilhena
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.,Department of Physics, University of Basel, Klingelbergstrasse 82, CH 4056 Basel, Switzerland
| | - Rubén Pérez
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.,Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Borja Ibarra
- IMDEA Nanociencia, C/Faraday 9, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain.,Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia) & CNB-CSIC-IMDEA Nanociencia Associated Unit 'Unidad de Nanobiotecnología', 28049 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
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33
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Singh J, Purohit PK. Statistical mechanics of a double-stranded rod model for DNA melting and elasticity. SOFT MATTER 2020; 16:7715-7726. [PMID: 32734998 PMCID: PMC7484343 DOI: 10.1039/d0sm00521e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The double-helical topology of DNA molecules observed at room temperature in the absence of any external loads can be disrupted by increasing the bath temperature or by applying tensile forces, leading to spontaneous strand separation known as DNA melting. Here, continuum mechanics of a 2D birod is combined with statistical mechanics to formulate a unified framework for studying both thermal melting and tensile force induced melting of double-stranded molecules: it predicts the variation of melting temperature with tensile load, provides a mechanics-based understanding of the cooperativity observed in melting transitions, and reveals an interplay between solution electrostatics and micromechanical deformations of DNA which manifests itself as an increase in the melting temperature with increasing ion concentration. This novel predictive framework sheds light on the micromechanical aspects of DNA melting and predicts trends that were observed experimentally or extracted phenomenologically using the Clayperon equation.
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Affiliation(s)
- Jaspreet Singh
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, 19104, USA.
| | - Prashant K Purohit
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, 19104, USA.
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34
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Morgan IL, Avinery R, Rahamim G, Beck R, Saleh OA. Glassy Dynamics and Memory Effects in an Intrinsically Disordered Protein Construct. PHYSICAL REVIEW LETTERS 2020; 125:058001. [PMID: 32794838 DOI: 10.1103/physrevlett.125.058001] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 07/07/2020] [Indexed: 06/11/2023]
Abstract
Glassy, nonexponential relaxations in globular proteins are typically attributed to conformational behaviors that are missing from intrinsically disordered proteins. Yet, we show that single molecules of a disordered-protein construct display two signatures of glassy dynamics, logarithmic relaxations and a Kovacs memory effect, in response to changes in applied tension. We attribute this to the presence of multiple independent local structures in the chain, which we corroborate with a model that correctly predicts the force dependence of the relaxation. The mechanism established here likely applies to other disordered proteins.
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Affiliation(s)
- Ian L Morgan
- BMSE Program, University of California, Santa Barbara, California 93106, USA
| | - Ram Avinery
- The Raymond and Beverly Sackler School of Physics and Astronomy and The Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Gil Rahamim
- The Raymond and Beverly Sackler School of Physics and Astronomy and The Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Roy Beck
- The Raymond and Beverly Sackler School of Physics and Astronomy and The Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Omar A Saleh
- BMSE Program, University of California, Santa Barbara, California 93106, USA
- Materials Department, University of California, Santa Barbara, California 93106, USA
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35
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Nikam R, Xu X, Kanduč M, Dzubiella J. Competitive sorption of monovalent and divalent ions by highly charged globular macromolecules. J Chem Phys 2020; 153:044904. [DOI: 10.1063/5.0018306] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Rohit Nikam
- Research Group for Simulations of Energy Materials, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
- Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489 Berlin, Germany
| | - Xiao Xu
- School of Chemical Engineering, Nanjing University of Science and Technology, 200 Xiao Ling Wei, Nanjing 210094, People’s Republic of China
| | - Matej Kanduč
- Department of Theoretical Physics, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Joachim Dzubiella
- Research Group for Simulations of Energy Materials, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
- Applied Theoretical Physics – Computational Physics, Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg, Germany
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36
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Osada K. Structural Polymorphism of Single pDNA Condensates Elicited by Cationic Block Polyelectrolytes. Polymers (Basel) 2020; 12:polym12071603. [PMID: 32707655 PMCID: PMC7408586 DOI: 10.3390/polym12071603] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/15/2020] [Accepted: 07/16/2020] [Indexed: 12/17/2022] Open
Abstract
DNA folding is a core phenomenon in genome packaging within a nucleus. Such a phenomenon is induced by polyelectrolyte complexation between anionic DNA and cationic proteins of histones. In this regard, complexes formed between DNA and cationic polyelectrolytes have been investigated as models to gain insight into genome packaging. Upon complexation, DNA undergoes folding to reduce its occupied volume, which often results in multi-complex associated aggregates. However, when cationic copolymers comprising a polycation block and a neutral hydrophilic polymer block are used instead, DNA undergoes folding as a single molecule within a spontaneously formed polyplex micelle (PM), thereby allowing the observation of the higher-order structures that DNA forms. The DNA complex forms polymorphic structures, including globular, rod-shaped, and ring-shaped (toroidal) structures. This review focuses on the polymorphism of DNA, particularly, to elucidate when, how, and why DNA organizes into these structures with cationic copolymers. The interactions between DNA and the copolymers, and the specific nature of DNA in rigidity; i.e., rigid but foldable, play significant roles in the observed polymorphism. Moreover, PMs serve as potential gene vectors for systemic application. The significance of the controlled DNA folding for such an application is addressed briefly in the last part.
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Affiliation(s)
- Kensuke Osada
- Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology (QST), Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555, Japan
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37
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Significant Differences in RNA Structure Destabilization by HIV-1 GagDp6 and NCp7 Proteins. Viruses 2020; 12:v12050484. [PMID: 32344834 PMCID: PMC7290599 DOI: 10.3390/v12050484] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/15/2020] [Accepted: 04/21/2020] [Indexed: 01/12/2023] Open
Abstract
Retroviral nucleocapsid (NC) proteins are nucleic acid chaperones that play distinct roles in the viral life cycle. During reverse transcription, HIV-1 NC facilitates the rearrangement of nucleic acid secondary structures, allowing the transactivation response (TAR) RNA hairpin to be transiently destabilized and annealed to a complementary RNA hairpin. In contrast, during viral assembly, NC, as a domain of the group-specific antigen (Gag) polyprotein, binds the genomic RNA and facilitates packaging into new virions. It is not clear how the same protein, alone or as part of Gag, performs such different RNA binding functions in the viral life cycle. By combining single-molecule optical tweezers measurements with a quantitative mfold-based model, we characterize the equilibrium stability and unfolding barrier for TAR RNA. Comparing measured results with a model of discrete protein binding allows us to localize affected binding sites, in addition to quantifying hairpin stability. We find that, while both NCp7 and Gag∆p6 destabilize the TAR hairpin, Gag∆p6 binding is localized to two sites in the stem, while NCp7 targets sites near the top loop. Unlike Gag∆p6, NCp7 destabilizes this loop, shifting the location of the reaction barrier toward the folded state and increasing the natural rate of hairpin opening by ~104. Thus, our results explain why Gag cleavage and NC release is an essential prerequisite for reverse transcription within the virion.
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38
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Ott K, Martini L, Lipfert J, Gerland U. Dynamics of the Buckling Transition in Double-Stranded DNA and RNA. Biophys J 2020; 118:1690-1701. [PMID: 32367807 PMCID: PMC7136337 DOI: 10.1016/j.bpj.2020.01.049] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 12/11/2019] [Accepted: 01/07/2020] [Indexed: 10/24/2022] Open
Abstract
DNA under torsional strain undergoes a buckling transition that is the fundamental step in plectoneme nucleation and supercoil dynamics, which are critical for the processing of genomic information. Despite its importance, quantitative models of the buckling transition, in particular to also explain the surprising two-orders-of-magnitude difference between the buckling times for RNA and DNA revealed by single-molecule tweezers experiments, are currently lacking. Additionally, little is known about the configurations of the DNA during the buckling transition because they are not directly observable experimentally. Here, we use a discrete worm-like chain model and Brownian dynamics to simulate the DNA/RNA buckling transition. Our simulations are in good agreement with experimentally determined parameters of the buckling transition. The simulations show that the buckling time strongly and exponentially depends on the bending stiffness, which accounts for more than half the measured difference between DNA and RNA. Analyzing the microscopic conformations of the chain revealed by our simulations, we find clear evidence for a solenoid-shaped transition state and a curl intermediate. The curl intermediate features a single loop and becomes increasingly populated at low forces. Taken together, the simulations suggest that the worm-like chain model can account semiquantitatively for the buckling dynamics of both DNA and RNA.
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Affiliation(s)
- Katharina Ott
- Physics of Complex Biosystems, Physics Department, Technical University of Munich, Garching, Germany
| | - Linda Martini
- Physics of Complex Biosystems, Physics Department, Technical University of Munich, Garching, Germany
| | - Jan Lipfert
- Department of Physics and Center for NanoScience, LMU Munich, Munich, Germany
| | - Ulrich Gerland
- Physics of Complex Biosystems, Physics Department, Technical University of Munich, Garching, Germany.
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39
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Bao Y, Luo Z, Cui S. Environment-dependent single-chain mechanics of synthetic polymers and biomacromolecules by atomic force microscopy-based single-molecule force spectroscopy and the implications for advanced polymer materials. Chem Soc Rev 2020; 49:2799-2827. [PMID: 32236171 DOI: 10.1039/c9cs00855a] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
"The Tao begets the One. One begets all things of the world." This quote from Tao Te Ching is still inspiring for scientists in chemistry and materials science: The "One" can refer to a single molecule. A macroscopic material is composed of numerous molecules. Although the relationship between the properties of the single molecule and macroscopic material is not well understood yet, it is expected that a deeper understanding of the single-chain mechanics of macromolecules will certainly facilitate the development of materials science. Atomic force microscopy-based single-molecule force spectroscopy (AFM-SMFS) has been exploited extensively as a powerful tool to study the single-chain behaviors of macromolecules. In this review, we summarize the recent advances in the emerging field of environment-dependent single-chain mechanics of synthetic polymers and biomacromolecules by means of AFM-SMFS. First, the single-chain inherent elasticities of several typical linear macromolecules are introduced, which are also confirmed by one of three polymer models with theoretical elasticities of the corresponding macromolecules obtained from quantum mechanical (QM) calculations. Then, the effects of the external environments on the single-chain mechanics of synthetic polymers and biomacromolecules are reviewed. Finally, the impacts of single-chain mechanics of macromolecules on the development of polymer science especially polymer materials are illustrated.
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Affiliation(s)
- Yu Bao
- Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China.
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40
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Shepherd JW, Greenall RJ, Probert M, Noy A, Leake M. The emergence of sequence-dependent structural motifs in stretched, torsionally constrained DNA. Nucleic Acids Res 2020; 48:1748-1763. [PMID: 31930331 PMCID: PMC7038985 DOI: 10.1093/nar/gkz1227] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 12/16/2019] [Accepted: 12/20/2019] [Indexed: 11/26/2022] Open
Abstract
The double-helical structure of DNA results from canonical base pairing and stacking interactions. However, variations from steady-state conformations resulting from mechanical perturbations in cells have physiological relevance but their dependence on sequence remains unclear. Here, we use molecular dynamics simulations showing sequence differences result in markedly different structural motifs upon physiological twisting and stretching. We simulate overextension on different sequences of DNA ((AA)12, (AT)12, (CC)12 and (CG)12) with supercoiling densities at 200 and 50 mM salt concentrations. We find that DNA denatures in the majority of stretching simulations, surprisingly including those with over-twisted DNA. GC-rich sequences are observed to be more stable than AT-rich ones, with the specific response dependent on the base pair order. Furthermore, we find that (AT)12 forms stable periodic structures with non-canonical hydrogen bonds in some regions and non-canonical stacking in others, whereas (CG)12 forms a stacking motif of four base pairs independent of supercoiling density. Our results demonstrate that 20-30% DNA extension is sufficient for breaking B-DNA around and significantly above cellular supercoiling, and that the DNA sequence is crucial for understanding structural changes under mechanical stress. Our findings have important implications for the activities of protein machinery interacting with DNA in all cells.
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Affiliation(s)
- Jack W Shepherd
- Department of Physics, University of York, York YO10 5DD, UK
| | | | | | - Agnes Noy
- Department of Physics, University of York, York YO10 5DD, UK
| | - Mark C Leake
- Department of Physics, University of York, York YO10 5DD, UK
- Department of Biology, University of York, York,YO10 5NG, UK
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41
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McCauley MJ, Rouzina I, Williams MC. Specific Nucleic Acid Chaperone Activity of HIV-1 Nucleocapsid Protein Deduced from Hairpin Unfolding. Methods Mol Biol 2020; 2106:59-88. [PMID: 31889251 DOI: 10.1007/978-1-0716-0231-7_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
RNA and DNA hairpin formation and disruption play key regulatory roles in a variety of cellular processes. The 59-nucleotide transactivation response (TAR) RNA hairpin facilitates the production of full-length transcripts of the HIV-1 genome. Yet the stability of this long, irregular hairpin becomes a liability during reverse transcription as 24 base pairs must be disrupted for strand transfer. Retroviral nucleocapsid (NC) proteins serve as nucleic acid chaperones that have been shown to both destabilize the TAR hairpin and facilitate strand annealing with its complementary DNA sequence. Yet it has remained difficult to elucidate the way NC targets and dramatically destabilizes this hairpin while only weakly affecting the annealed product. In this work, we used optical tweezers to measure the stability of TAR and found that adding NC destabilized the hairpin and simultaneously caused a distinct change in both the height and location of the energy barrier. This data was matched to an energy landscape predicted from a simple theory of definite base pair destabilization. Comparisons revealed the specific binding sites found by NC along the irregular TAR hairpin. Furthermore, specific binding explained both the unusual shift in the transition state and the much weaker effect on the annealed product. These experiments illustrate a general method of energy landscape transformation that exposes important physical insights.
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Affiliation(s)
| | - Ioulia Rouzina
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH, USA
| | - Mark C Williams
- Department of Physics, Northeastern University, Boston, MA, USA.
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42
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Velasco-Berrelleza V, Burman M, Shepherd JW, Leake MC, Golestanian R, Noy A. SerraNA: a program to determine nucleic acids elasticity from simulation data. Phys Chem Chem Phys 2020; 22:19254-19266. [DOI: 10.1039/d0cp02713h] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
AT-rich motifs can generate extreme mechanical properties, which are critical for creating strong global bends when phased properly.
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Affiliation(s)
| | | | | | - Mark C. Leake
- Department of Physics
- University of York
- York
- UK
- Department of Biology
| | - Ramin Golestanian
- Max Planck Institute for Dynamics and Self-Organization (MPIDS)
- Göttingen
- Germany
- Rudolf Peierls Center for Theoretical Physics
- University of Oxford
| | - Agnes Noy
- Department of Physics
- University of York
- York
- UK
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43
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Lu C, Le S, Chen J, Byrd AK, Rhodes D, Raney KD, Yan J. Direct quantification of the translocation activities of Saccharomyces cerevisiae Pif1 helicase. Nucleic Acids Res 2019; 47:7494-7501. [PMID: 31216020 PMCID: PMC6698741 DOI: 10.1093/nar/gkz541] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 05/10/2019] [Accepted: 06/07/2019] [Indexed: 02/04/2023] Open
Abstract
Saccharomyces cerevisiae Pif1 (ScPif1) is known as an ATP-dependent DNA helicase that plays critical roles in a number of important biological processes such as DNA replication, telomere maintenance and genome stability maintenance. Besides its DNA helicase activity, ScPif1 is also known as a single-stranded DNA (ssDNA) translocase, while how ScPif1 translocates on ssDNA is unclear. Here, by measuring the translocation activity of individual ScPif1 molecules on ssDNA extended by mechanical force, we identified two distinct types of ssDNA translocation. In one type, ScPif1 moves along the ssDNA track with a rate of ∼140 nt/s in 100 μM ATP, whereas in the other type, ScPif1 is immobilized to a fixed location of ssDNA and generates ssDNA loops against force. Between the two, the mobile translocation is the major form at nanomolar ScPif1 concentrations although patrolling becomes more frequent at micromolar concentrations. Together, our results suggest that ScPif1 translocates on extended ssDNA in two distinct modes, primarily in a ‘mobile’ manner.
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Affiliation(s)
- Chen Lu
- Mechanobiology Institute, National University of Singapore, Singapore 117411.,Centre for Bioimaging Sciences, National University of Singapore, Singapore 117557
| | - Shimin Le
- Department of Physics, National University of Singapore, Singapore 117542
| | - Jin Chen
- Mechanobiology Institute, National University of Singapore, Singapore 117411
| | - Alicia K Byrd
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Science, Arkansas 72205, USA
| | - Daniela Rhodes
- School of Biological Sciences, Nanyang Technology University, Singapore 637551
| | - Kevin D Raney
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Science, Arkansas 72205, USA
| | - Jie Yan
- Mechanobiology Institute, National University of Singapore, Singapore 117411.,Centre for Bioimaging Sciences, National University of Singapore, Singapore 117557.,Department of Physics, National University of Singapore, Singapore 117542
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44
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Ordu O, Lusser A, Dekker NH. DNA Sequence Is a Major Determinant of Tetrasome Dynamics. Biophys J 2019; 117:2217-2227. [PMID: 31521330 PMCID: PMC6895708 DOI: 10.1016/j.bpj.2019.07.055] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 07/13/2019] [Accepted: 07/30/2019] [Indexed: 10/26/2022] Open
Abstract
Eukaryotic genomes are hierarchically organized into protein-DNA assemblies for compaction into the nucleus. Nucleosomes, with the (H3-H4)2 tetrasome as a likely intermediate, are highly dynamic in nature by way of several different mechanisms. We have recently shown that tetrasomes spontaneously change the direction of their DNA wrapping between left- and right-handed conformations, which may prevent torque buildup in chromatin during active transcription or replication. DNA sequence has been shown to strongly affect nucleosome positioning throughout chromatin. It is not known, however, whether DNA sequence also impacts the dynamic properties of tetrasomes. To address this question, we examined tetrasomes assembled on a high-affinity DNA sequence using freely orbiting magnetic tweezers. In this context, we also studied the effects of mono- and divalent salts on the flipping dynamics. We found that neither DNA sequence nor altered buffer conditions affect overall tetrasome structure. In contrast, tetrasomes bound to high-affinity DNA sequences showed significantly altered flipping kinetics, predominantly via a reduction in the lifetime of the canonical state of left-handed wrapping. Increased mono- and divalent salt concentrations counteracted this behavior. Thus, our study indicates that high-affinity DNA sequences impact not only the positioning of the nucleosome but that they also endow the subnucleosomal tetrasome with enhanced conformational plasticity. This may provide a means to prevent histone loss upon exposure to torsional stress, thereby contributing to the integrity of chromatin at high-affinity sites.
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Affiliation(s)
- Orkide Ordu
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Alexandra Lusser
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Nynke H Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands.
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45
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Xu X, Makaraviciute A, Kumar S, Wen C, Sjödin M, Abdurakhmanov E, Danielson UH, Nyholm L, Zhang Z. Structural Changes of Mercaptohexanol Self-Assembled Monolayers on Gold and Their Influence on Impedimetric Aptamer Sensors. Anal Chem 2019; 91:14697-14704. [PMID: 31650834 DOI: 10.1021/acs.analchem.9b03946] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Despite a large number of publications describing biosensors based on electrochemical impedance spectroscopy (EIS), little attention has been paid to the stability and reproducibility issues of the sensor interfaces. In this work, the stability and reproducibility of faradaic EIS analyses on the aptamer/mercaptohexanol (MCH) self-assembled monolayer (SAM)-functionalized gold surfaces in ferri- and ferrocyanide solution were systematically evaluated prior to and after the aptamer-probe DNA hybridization. It is shown that the EIS data exhibited significant drift, and this significantly affected the reproducibility of the EIS signal of the hybridization. As a result, no significant difference between the charge transfer resistance (RCT) changes induced by the aptamer-target DNA hybridization and that caused by the drift could be identified. A conditioning of the electrode in the measurement solution for more than 12 h was required to reach a stable RCT baseline prior to the aptamer-probe DNA hybridization. The monitored drift in RCT and double layer capacitance during the conditioning suggests that the MCH SAM on the gold surface reorganized to a thinner but more closely packed layer. We also observed that the hot binding buffer used in the following aptamer-probe DNA hybridization process could induce additional MCH and aptamer reorganization, and thus further drift in RCT. As a result, the RCT change caused by the aptamer-probe DNA hybridization was less than that caused by the hot binding buffer (blank control experiment). Therefore, it is suggested that the use of high temperature in the EIS measurement should be carefully evaluated or avoided. This work provides practical guidelines for the EIS measurements. Moreover, because SAM-functionalized gold electrodes are widely used in biosensors, for example, DNA sensors, an improved understanding of the origin of the observed drift is very important for the development of well-functioning and reproducible biosensors.
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Affiliation(s)
| | | | - Shalen Kumar
- School of Biological Sciences , Victoria University of Wellington , Wellington 6140 , New Zealand.,AuramerBio Limited, Callaghan Innovation Quarter , 69 Seaview Road , Gracefield, Lower Hutt 5010 , New Zealand
| | | | | | - Eldar Abdurakhmanov
- Department of Chemistry-BMC and Science for Life Laboratory , Uppsala University , P.O. Box 576, Uppsala SE-751 23 , Sweden
| | - U Helena Danielson
- Department of Chemistry-BMC and Science for Life Laboratory , Uppsala University , P.O. Box 576, Uppsala SE-751 23 , Sweden
| | - Leif Nyholm
- Department of Chemistry, The Ångström Laboratory , Uppsala University , P.O. Box 538, Uppsala SE-751 21 , Sweden
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46
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Moreno-Guerra JA, Romero-Sánchez IC, Martinez-Borquez A, Tassieri M, Stiakakis E, Laurati M. Model-Free Rheo-AFM Probes the Viscoelasticity of Tunable DNA Soft Colloids. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1904136. [PMID: 31460707 DOI: 10.1002/smll.201904136] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Indexed: 05/23/2023]
Abstract
Atomic force microscopy rheological measurements (Rheo-AFM) of the linear viscoelastic properties of single, charged colloids having a star-like architecture with a hard core and an extended, deformable double-stranded DNA (dsDNA) corona dispersed in aqueous saline solutions are reported. This is achieved by analyzing indentation and relaxation experiments performed on individual colloidal particles by means of a novel model-free Fourier transform method that allows a direct evaluation of the frequency-dependent linear viscoelastic moduli of the system under investigation. The method provides results that are consistent with those obtained via a conventional fitting procedure of the force-relaxation curves based on a modified Maxwell model. The outcomes show a pronounced softening of the dsDNA colloids, which is described by an exponential decay of both the Young's and the storage modulus as a function of the salt concentration within the dispersing medium. The strong softening is related to a critical reduction of the size of the dsDNA corona, down to ≈70% of its size in a salt-free solution. This can be correlated to significant topological changes of the dense star-like polyelectrolyte forming the corona, which are induced by variations in the density profile of the counterions. Similarly, a significant reduction of the stiffness is obtained by increasing the length of the dsDNA chains, which we attribute to a reduction of the DNA density in the outer region of the corona.
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Affiliation(s)
- José A Moreno-Guerra
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Lomas del Bosque 103, 37150, León, Mexico
| | - Ivany C Romero-Sánchez
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Lomas del Bosque 103, 37150, León, Mexico
| | - Alejandro Martinez-Borquez
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Lomas del Bosque 103, 37150, León, Mexico
| | - Manlio Tassieri
- Division of Biomedical Engineering, School of Engineering, University of Glasgow, Glasgow, G12 8LT, UK
| | - Emmanuel Stiakakis
- Forschungszentrum Jülich, Institute of Complex Systems 3, Leo-Brandt-Strasse, 52425, Jülich, Germany
| | - Marco Laurati
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Lomas del Bosque 103, 37150, León, Mexico
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47
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Xiao S, Liang H, Wales DJ. The Contribution of Backbone Electrostatic Repulsion to DNA Mechanical Properties is Length-Scale-Dependent. J Phys Chem Lett 2019; 10:4829-4835. [PMID: 31380654 DOI: 10.1021/acs.jpclett.9b01960] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The mechanics of DNA bending is crucially related to many vital biological processes. Recent experiments reported anomalous flexibility for DNA on short length scales, calling into doubt the validity of the harmonic worm-like chain (WLC) model in this region. In the present work, we systematically probed the bending dynamics of DNA at different length scales. In contrast to the remarkable deviation from the WLC description for DNA duplexes of less than three helical turns, our atomistic studies indicate that the neutral "null isomer" behaves in accord with the ideal elastic WLC and exhibits a uniform decay for the directional correlation of local bending. The backbone neutralization weakens the anisotropy in the effective bending preference and the helical periodicity of bend correlation that have previously been observed for normal DNA. The contribution of electrostatic repulsion to stretching cooperativity and the mechanical properties of DNA strands is length-scale-dependent: the phosphate neutralization increases the stiffness of DNA below two helical turns, but it is decreased for longer strands. We find that DNA rigidity is largely determined by base pair stacking, with electrostatic interactions contributing only around 10% of the total persistence length.
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Affiliation(s)
- Shiyan Xiao
- CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Polymer Science and Engineering, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, P.R. China
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Haojun Liang
- CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Polymer Science and Engineering, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, P.R. China
| | - David J Wales
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
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48
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Liu JH, Xi K, Zhang X, Bao L, Zhang X, Tan ZJ. Structural Flexibility of DNA-RNA Hybrid Duplex: Stretching and Twist-Stretch Coupling. Biophys J 2019; 117:74-86. [PMID: 31164196 PMCID: PMC6626833 DOI: 10.1016/j.bpj.2019.05.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 04/25/2019] [Accepted: 05/17/2019] [Indexed: 12/21/2022] Open
Abstract
DNA-RNA hybrid (DRH) duplexes play essential roles during the replication of DNA and the reverse transcription of RNA viruses, and their flexibility is important for their biological functions. Recent experiments indicated that A-form RNA and B-form DNA have a strikingly different flexibility in stretching and twist-stretch coupling, and the structural flexibility of DRH duplex is of great interest, especially in stretching and twist-stretch coupling. In this work, we performed microsecond all-atom molecular dynamics simulations with new AMBER force fields to characterize the structural flexibility of DRH duplex in stretching and twist-stretch coupling. We have calculated all the helical parameters, stretch modulus, and twist-stretch coupling parameters for the DRH duplex. First, our analyses on structure suggest that the DRH duplex exhibits an intermediate conformation between A- and B-forms and closer to A-form, which can be attributed to the stronger rigidity of the RNA strand than the DNA strand. Second, our calculations show that the DRH duplex has the stretch modulus of 834 ± 34 pN and a very weak twist-stretch coupling. Our quantitative analyses indicate that, compared with DNA and RNA duplexes, the different flexibility of the DRH duplex in stretching and twist-stretch coupling is mainly attributed to its apparently different basepair inclination in the helical structure.
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Affiliation(s)
- Ju-Hui Liu
- Center for Theoretical Physics and Key Laboratory of Artificial Micro- & Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan, China
| | - Kun Xi
- Center for Theoretical Physics and Key Laboratory of Artificial Micro- & Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan, China
| | - Xi Zhang
- Center for Theoretical Physics and Key Laboratory of Artificial Micro- & Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan, China
| | - Lei Bao
- Center for Theoretical Physics and Key Laboratory of Artificial Micro- & Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan, China
| | - Xinghua Zhang
- College of Life Science, the Institute for Advanced Studies, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, Wuhan University, Wuhan, China.
| | - Zhi-Jie Tan
- Center for Theoretical Physics and Key Laboratory of Artificial Micro- & Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan, China.
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49
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Marin-Gonzalez A, Vilhena JG, Moreno-Herrero F, Perez R. DNA Crookedness Regulates DNA Mechanical Properties at Short Length Scales. PHYSICAL REVIEW LETTERS 2019; 122:048102. [PMID: 30768347 DOI: 10.1103/physrevlett.122.048102] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Indexed: 05/13/2023]
Abstract
Sequence-dependent DNA conformation and flexibility play a fundamental role in the specificity of DNA-protein interactions. Here we quantify the DNA crookedness: a sequence-dependent deformation of DNA that consists of periodic bends of the base pair centers chain. Using extensive 100 μs-long, all-atom molecular dynamics simulations, we found that DNA crookedness and its associated flexibility are bijective, which unveils a one-to-one relation between DNA structure and dynamics. This allowed us to build a predictive model to compute the stretch moduli of different DNA sequences from solely their structure. Sequences with very little crookedness show extremely high stretching stiffness and have been previously shown to form unstable nucleosomes and promote gene expression. Interestingly, the crookedness can be tailored by epigenetic modifications, known to affect gene expression. Our results rationalize the idea that the DNA sequence is not only a chemical code, but also a physical one that allows finely regulating its mechanical properties and, possibly, its 3D arrangement inside the cell.
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Affiliation(s)
- Alberto Marin-Gonzalez
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Cantoblanco, Madrid, Spain
| | - J G Vilhena
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH 4056 Basel, Switzerland
| | - Fernando Moreno-Herrero
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Cantoblanco, Madrid, Spain
| | - Ruben Perez
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
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50
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Cristofalo M, Kovari D, Corti R, Salerno D, Cassina V, Dunlap D, Mantegazza F. Nanomechanics of Diaminopurine-Substituted DNA. Biophys J 2019; 116:760-771. [PMID: 30795872 DOI: 10.1016/j.bpj.2019.01.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 01/23/2019] [Accepted: 01/24/2019] [Indexed: 10/27/2022] Open
Abstract
2,6-diaminopurine (DAP) is a nucleobase analog of adenine. When incorporated into double-stranded DNA (dsDNA), it forms three hydrogen bonds with thymine. Rare in nature, DAP substitution alters the physical characteristics of a DNA molecule without sacrificing sequence specificity. Here, we show that in addition to stabilizing double-strand hybridization, DAP substitution also changes the mechanical and conformational properties of dsDNA. Thermal melting experiments reveal that DAP substitution raises melting temperatures without diminishing sequence-dependent effects. Using a combination of atomic force microscopy (AFM), magnetic tweezer (MT) nanomechanical assays, and circular dichroism spectroscopy, we demonstrate that DAP substitution increases the flexural rigidity of dsDNA yet also facilitates conformational shifts, which manifest as changes in molecule length. DAP substitution increases both the static and dynamic persistence length of DNA (measured by AFM and MT, respectively). In the static case (AFM), in which tension is not applied to the molecule, the contour length of DAP-DNA appears shorter than wild-type (WT)-DNA; under tension (MT), they have similar dynamic contour lengths. At tensions above 60 pN, WT-DNA undergoes characteristic overstretching because of strand separation (tension-induced melting) and spontaneous adoption of a conformation termed S-DNA. Cyclic overstretching and relaxation of WT-DNA at near-zero loading rates typically yields hysteresis, indicative of tension-induced melting; conversely, cyclic stretching of DAP-DNA showed little or no hysteresis, consistent with the adoption of the S-form, similar to what has been reported for GC-rich sequences. However, DAP-DNA overstretching is distinct from GC-rich overstretching in that it happens at a significantly lower tension. In physiological salt conditions, evenly mixed AT/GC DNA typically overstretches around 60 pN. GC-rich sequences overstretch at similar if not slightly higher tensions. Here, we show that DAP-DNA overstretches at 52 pN. In summary, DAP substitution decreases the overall stability of the B-form double helix, biasing toward non-B-form DNA helix conformations at zero tension and facilitating the B-to-S transition at high tension.
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Affiliation(s)
- Matteo Cristofalo
- School of Medicine and Surgery, Università di Milano-Bicocca, Monza (MB), Italy
| | - Daniel Kovari
- Department of Physics, Emory University, Atlanta, Georgia
| | - Roberta Corti
- School of Medicine and Surgery, Università di Milano-Bicocca, Monza (MB), Italy
| | - Domenico Salerno
- School of Medicine and Surgery, Università di Milano-Bicocca, Monza (MB), Italy.
| | - Valeria Cassina
- School of Medicine and Surgery, Università di Milano-Bicocca, Monza (MB), Italy
| | - David Dunlap
- Department of Physics, Emory University, Atlanta, Georgia.
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