1
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Wang X, Huang T, Li L, Xu Y. Effect of temperature on anisotropic bending elasticity of dsRNA: an all-atom molecular dynamics simulation. RSC Adv 2024; 14:17170-17177. [PMID: 38808231 PMCID: PMC11130765 DOI: 10.1039/d4ra02354d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 05/17/2024] [Indexed: 05/30/2024] Open
Abstract
Employing all-atom molecular dynamics simulations, we examined the temperature-dependent behavior of bending elasticity in double-stranded RNA (dsRNA). Specifically, we focused on the bending persistence length and its constituent components, namely, the tilt and roll stiffness. Our results revealed a near-linear decrease in these stiffness components as a function of temperature, thereby highlighting the increased flexibility of dsRNA at elevated temperatures. Furthermore, our data revealed a significant anisotropy in dsRNA bending elasticity, which diminished with increasing temperature, attributable to marked disparities in tilt and roll stiffness components. We delineated the underlying biophysical mechanisms and corroborated our findings with extant literature. These observations offer salient implications for advancing our understanding of nucleic acid elasticity, and are pertinent to potential medical applications.
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Affiliation(s)
- Xianghong Wang
- School of Sino-German Engineering, Shanghai Technical Institute of Electronics and Information Shanghai 201411 China
| | - Tingting Huang
- School of Sino-German Engineering, Shanghai Technical Institute of Electronics and Information Shanghai 201411 China
| | - Liyun Li
- Department of Physics, Wenzhou University Wenzhou 325035 China
| | - Yanliang Xu
- School of Sino-German Engineering, Shanghai Technical Institute of Electronics and Information Shanghai 201411 China
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2
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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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3
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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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4
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Dohnalová H, Matoušková E, Lankaš F. Temperature-dependent elasticity of DNA, RNA, and hybrid double helices. Biophys J 2024; 123:572-583. [PMID: 38340722 PMCID: PMC10938081 DOI: 10.1016/j.bpj.2024.01.032] [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: 10/08/2023] [Revised: 12/19/2023] [Accepted: 01/26/2024] [Indexed: 02/12/2024] Open
Abstract
Nucleic acid double helices in their DNA, RNA, and DNA-RNA hybrid form play a fundamental role in biology and are main building blocks of artificial nanostructures, but how their properties depend on temperature remains poorly understood. Here, we report thermal dependence of dynamic bending persistence length, twist rigidity, stretch modulus, and twist-stretch coupling for DNA, RNA, and hybrid duplexes between 7°C and 47°C. The results are based on all-atom molecular dynamics simulations using different force field parameterizations. We first demonstrate that unrestrained molecular dynamics can reproduce experimentally known mechanical properties of the duplexes at room temperature. Beyond experimentally known features, we also infer the twist rigidity and twist-stretch coupling of the hybrid duplex. As for the temperature dependence, we found that increasing temperature softens all the duplexes with respect to bending, twisting, and stretching. The relative decrease of the stretch moduli is 0.003-0.004/°C, similar for all the duplex variants despite their very different stretching stiffness, whereas RNA twist stiffness decreases by 0.003/°C, and smaller values are found for the other elastic moduli. The twist-stretch couplings are nearly unaffected by temperature. The stretching, bending, and twisting stiffness all include an important entropic component. Relation of our results to the two-state model of DNA flexibility is discussed. Our work provides temperature-dependent elasticity of nucleic acid duplexes at the microsecond scale relevant for initial stages of protein binding.
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Affiliation(s)
- Hana Dohnalová
- Department of Informatics and Chemistry, University of Chemistry and Technology Prague, Praha 6, Czech Republic
| | - Eva Matoušková
- Department of Informatics and Chemistry, University of Chemistry and Technology Prague, Praha 6, Czech Republic
| | - Filip Lankaš
- Department of Informatics and Chemistry, University of Chemistry and Technology Prague, Praha 6, Czech Republic.
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5
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Chandrasekhar S, Swope TP, Fadaei F, Hollis DR, Bricker R, Houser D, Portman J, Schmidt TL. Bending Unwinds DNA. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.14.579968. [PMID: 38405957 PMCID: PMC10888926 DOI: 10.1101/2024.02.14.579968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
In biology, DNA is often tightly bent to small radii. Solely based on the groove asymmetry, a 30-year-old theoretical paper predicted that such bending should unwind DNA, but this effect has not been directly experimentally quantified so far. We developed a ligation-based assay with nicked DNA circles of variable length, thereby decoupling the twist-dependent ligation efficiency from the large bending strain which dominates conventional circularization assays. We demonstrate that tightly bent DNA indeed unwinds to over 11 base pairs/turn, exactly as predicted. Our discovery requires reassessing the molecular mechanisms and energetics of all processes where DNA is tightly bent or relaxed again, including DNA packaging, gene regulation and expression.
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Affiliation(s)
- Soumya Chandrasekhar
- Department of Physics, Kent State University, Kent, OH, 44242, USA
- Contributed equally
| | - Thomas P. Swope
- Department of Physics, Kent State University, Kent, OH, 44242, USA
- Contributed equally
| | - Fatemeh Fadaei
- Department of Physics, Kent State University, Kent, OH, 44242, USA
| | - Daniel R. Hollis
- Department of Physics, Kent State University, Kent, OH, 44242, USA
| | - Rachel Bricker
- Department of Physics, Kent State University, Kent, OH, 44242, USA
| | - Draven Houser
- Department of Physics, Kent State University, Kent, OH, 44242, USA
| | - John Portman
- Department of Physics, Kent State University, Kent, OH, 44242, USA
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6
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Cleri F, Giordano S, Blossey R. Nucleosome Array Deformation in Chromatin is Sustained by Bending, Twisting and Kinking of Linker DNA. J Mol Biol 2023; 435:168263. [PMID: 37678705 DOI: 10.1016/j.jmb.2023.168263] [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: 07/08/2023] [Revised: 08/21/2023] [Accepted: 08/30/2023] [Indexed: 09/09/2023]
Abstract
Chromatin in the nucleus undergoes mechanical stresses from different sources during the various stages of cell life. Here a trinucleosome array is used as the minimal model to study the mechanical response to applied stress at the molecular level. By using large-scale, all-atom steered-molecular dynamics simulations, we show that the largest part of mechanical stress in compression is accommodated by the DNA linkers joining pairs of nucleosomes, which store the elastic energy accumulated by the applied force. Different mechanical instabilities (Euler bending, Brazier kinking, twist-bending) can deform the DNA canonical structure, as a function of the increasing force load. An important role of the histone tails in assisting the DNA deformation is highlighted. The overall response of the smallest chromatin fragment to compressive stress leaves the nucleosome assembly with a substantial plastic deformation and localised defects, which can have a potential impact on DNA transcription, downstream signaling pathways, the regulation of gene expression, and DNA repair.
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Affiliation(s)
- Fabrizio Cleri
- Université de Lille, Institut d'Electronique Microelectronique et Nanotechnologie (IEMN CNRS UMR8520) and Département de Physique, 59652 Villeneuve d'Ascq, France.
| | - Stefano Giordano
- University of Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, UMR 8520 - IEMN - Institut d'Électronique de Microélectronique et de Nanotechnologie, F-59000 Lille, France
| | - Ralf Blossey
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France
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7
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Madrid I, Zheng Z, Gerbelot C, Fujiwara A, Li S, Grall S, Nishiguchi K, Kim SH, Chovin A, Demaille C, Clement N. Ballistic Brownian Motion of Nanoconfined DNA. ACS NANO 2023; 17:17031-17040. [PMID: 37700490 DOI: 10.1021/acsnano.3c04349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/14/2023]
Abstract
Theoretical treatments of polymer dynamics in liquid generally start with the basic assumption that motion at the smallest scale is heavily overdamped; therefore, inertia can be neglected. We report on the Brownian motion of tethered DNA under nanoconfinement, which was analyzed by molecular dynamics simulation and nanoelectrochemistry-based single-electron shuttle experiments. Our results show a transition into the ballistic Brownian motion regime for short DNA in sub-5 nm gaps, with quality coefficients as high as 2 for double-stranded DNA, an effect mainly attributed to a drastic increase in stiffness. The possibility for DNA to enter the underdamped regime could have profound implications on our understanding of the energetics of biomolecular engines such as the replication machinery, which operates in nanocavities that are a few nanometers wide.
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Affiliation(s)
- Ignacio Madrid
- IIS, LIMMS CNRS-IIS UMI2820, The University of Tokyo, 4-6-1 Komaba, Meguro-ku Tokyo 153-8505, Japan
| | - Zhiyong Zheng
- Laboratoire d'Electrochimie Moléculaire, UMR 7591 CNRS, Université Paris Cité, 15 rue Jean-Antoine de Baïf, F-75205 Paris Cedex 13, France
| | - Cedric Gerbelot
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi-shi 243-0198, Japan
| | - Akira Fujiwara
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi-shi 243-0198, Japan
| | - Shuo Li
- IIS, LIMMS CNRS-IIS UMI2820, The University of Tokyo, 4-6-1 Komaba, Meguro-ku Tokyo 153-8505, Japan
| | - Simon Grall
- IIS, LIMMS CNRS-IIS UMI2820, The University of Tokyo, 4-6-1 Komaba, Meguro-ku Tokyo 153-8505, Japan
| | - Katsuhiko Nishiguchi
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi-shi 243-0198, Japan
| | - Soo Hyeon Kim
- IIS, LIMMS CNRS-IIS UMI2820, The University of Tokyo, 4-6-1 Komaba, Meguro-ku Tokyo 153-8505, Japan
| | - Arnaud Chovin
- Laboratoire d'Electrochimie Moléculaire, UMR 7591 CNRS, Université Paris Cité, 15 rue Jean-Antoine de Baïf, F-75205 Paris Cedex 13, France
| | - Christophe Demaille
- Laboratoire d'Electrochimie Moléculaire, UMR 7591 CNRS, Université Paris Cité, 15 rue Jean-Antoine de Baïf, F-75205 Paris Cedex 13, France
| | - Nicolas Clement
- IIS, LIMMS CNRS-IIS UMI2820, The University of Tokyo, 4-6-1 Komaba, Meguro-ku Tokyo 153-8505, Japan
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi-shi 243-0198, Japan
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8
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Mu ZC, Tan YL, Liu J, Zhang BG, Shi YZ. Computational Modeling of DNA 3D Structures: From Dynamics and Mechanics to Folding. Molecules 2023; 28:4833. [PMID: 37375388 DOI: 10.3390/molecules28124833] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 06/11/2023] [Accepted: 06/14/2023] [Indexed: 06/29/2023] Open
Abstract
DNA carries the genetic information required for the synthesis of RNA and proteins and plays an important role in many processes of biological development. Understanding the three-dimensional (3D) structures and dynamics of DNA is crucial for understanding their biological functions and guiding the development of novel materials. In this review, we discuss the recent advancements in computer methods for studying DNA 3D structures. This includes molecular dynamics simulations to analyze DNA dynamics, flexibility, and ion binding. We also explore various coarse-grained models used for DNA structure prediction or folding, along with fragment assembly methods for constructing DNA 3D structures. Furthermore, we also discuss the advantages and disadvantages of these methods and highlight their differences.
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Affiliation(s)
- Zi-Chun Mu
- Research Center of Nonlinear Science, School of Mathematical & Physical Sciences, Wuhan Textile University, Wuhan 430073, China
- School of Computer Science and Artificial Intelligence, Wuhan Textile University, Wuhan 430073, China
| | - Ya-Lan Tan
- Research Center of Nonlinear Science, School of Mathematical & Physical Sciences, Wuhan Textile University, Wuhan 430073, China
| | - Jie Liu
- Research Center of Nonlinear Science, School of Mathematical & Physical Sciences, Wuhan Textile University, Wuhan 430073, China
| | - Ben-Gong Zhang
- Research Center of Nonlinear Science, School of Mathematical & Physical Sciences, Wuhan Textile University, Wuhan 430073, China
| | - Ya-Zhou Shi
- Research Center of Nonlinear Science, School of Mathematical & Physical Sciences, Wuhan Textile University, Wuhan 430073, China
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9
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Nguyen NTT, Ngo AT, Hoang TX. Energetic preference and topological constraint effects on the formation of DNA twisted toroidal bundles. J Chem Phys 2023; 158:114904. [PMID: 36948817 DOI: 10.1063/5.0134710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023] Open
Abstract
DNA toroids are compact torus-shaped bundles formed by one or multiple DNA molecules being condensed from the solution due to various condensing agents. It has been shown that the DNA toroidal bundles are twisted. However, the global conformations of DNA inside these bundles are still not well understood. In this study, we investigate this issue by solving different models for the toroidal bundles and performing replica-exchange molecular dynamics (REMD) simulations for self-attractive stiff polymers of various chain lengths. We find that a moderate degree of twisting is energetically favorable for toroidal bundles, yielding optimal configurations of lower energies than for other bundles corresponding to spool-like and constant radius of curvature arrangements. The REMD simulations show that the ground states of the stiff polymers are twisted toroidal bundles with the average twist degrees close to those predicted by the theoretical model. Constant-temperature simulations show that twisted toroidal bundles can be formed through successive processes of nucleation, growth, quick tightening, and slow tightening of the toroid, with the two last processes facilitating the polymer threading through the toroid's hole. A relatively long chain of 512 beads has an increased dynamical difficulty to access the twisted bundle states due to the polymer's topological constraint. Interestingly, we also observed significantly twisted toroidal bundles with a sharp U-shaped region in the polymer conformation. It is suggested that this U-shaped region makes the formation of twisted bundles easier by effectively reducing the polymer length. This effect can be equivalent to having multiple chains in the toroid.
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Affiliation(s)
- Nhung T T Nguyen
- Institute of Physics, Vietnam Academy of Science and Technology, 10 Dao Tan, Ba Dinh, Hanoi 11108, Vietnam
| | - Anh T Ngo
- Chemical Engineering Department, University of Illinois at Chicago, Chicago, Illinois 60608, USA
| | - Trinh X Hoang
- Institute of Physics, Vietnam Academy of Science and Technology, 10 Dao Tan, Ba Dinh, Hanoi 11108, Vietnam
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10
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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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11
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Gutiérrez Fosado YA, Landuzzi F, Sakaue T. Coarse Graining DNA: Symmetry, Nonlocal Elasticity, and Persistence Length. PHYSICAL REVIEW LETTERS 2023; 130:058402. [PMID: 36800451 DOI: 10.1103/physrevlett.130.058402] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 01/06/2023] [Indexed: 06/18/2023]
Abstract
While the behavior of double-stranded DNA at mesoscopic scales is fairly well understood, less is known about its relation to the rich mechanical properties in the base-pair scale, which is crucial, for instance, to understand DNA-protein interactions and the nucleosome diffusion mechanism. Here, by employing the rigid base-pair model, we connect its microscopic parameters to the persistence length. Combined with all-atom molecular dynamic simulations, our scheme identifies relevant couplings between different degrees of freedom at each coarse-graining step. This allows us to clarify how the scale dependence of the elastic moduli is determined in a systematic way encompassing the role of previously unnoticed off-site couplings between deformations with different parity.
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Affiliation(s)
- Yair Augusto Gutiérrez Fosado
- School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, United Kingdom
| | - Fabio Landuzzi
- Centro CMP3VdA, Istituto Italiano di Tecnologia, via Lavoratori Vittime del Col du Mont 28, 11100, Aosta, Italy
| | - Takahiro Sakaue
- Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara-shi, Kanagawa 252-5258, Japan
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12
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Mu ZC, Tan YL, Zhang BG, Liu J, Shi YZ. Ab initio predictions for 3D structure and stability of single- and double-stranded DNAs in ion solutions. PLoS Comput Biol 2022; 18:e1010501. [PMID: 36260618 PMCID: PMC9621594 DOI: 10.1371/journal.pcbi.1010501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/31/2022] [Accepted: 09/27/2022] [Indexed: 11/07/2022] Open
Abstract
The three-dimensional (3D) structure and stability of DNA are essential to understand/control their biological functions and aid the development of novel materials. In this work, we present a coarse-grained (CG) model for DNA based on the RNA CG model proposed by us, to predict 3D structures and stability for both dsDNA and ssDNA from the sequence. Combined with a Monte Carlo simulated annealing algorithm and CG force fields involving the sequence-dependent base-pairing/stacking interactions and an implicit electrostatic potential, the present model successfully folds 20 dsDNAs (≤52nt) and 20 ssDNAs (≤74nt) into the corresponding native-like structures just from their sequences, with an overall mean RMSD of 3.4Å from the experimental structures. For DNAs with various lengths and sequences, the present model can make reliable predictions on stability, e.g., for 27 dsDNAs with/without bulge/internal loops and 24 ssDNAs including pseudoknot, the mean deviation of predicted melting temperatures from the corresponding experimental data is only ~2.0°C. Furthermore, the model also quantificationally predicts the effects of monovalent or divalent ions on the structure stability of ssDNAs/dsDNAs. To determine 3D structures and quantify stability of single- (ss) and double-stranded (ds) DNAs is essential to unveil the mechanisms of their functions and to further guide the production and development of novel materials. Although many DNA models have been proposed to reproduce the basic structural, mechanical, or thermodynamic properties of dsDNAs based on the secondary structure information or preset constraints, there are very few models can be used to investigate the ssDNA folding or dsDNA assembly from the sequence. Furthermore, due to the polyanionic nature of DNAs, metal ions (e.g., Na+ and Mg2+) in solutions can play an essential role in DNA folding and dynamics. Nevertheless, ab initio predictions for DNA folding in ion solutions are still an unresolved problem. In this work, we developed a novel coarse-grained model to predict 3D structures and thermodynamic stabilities for both ssDNAs and dsDNAs in monovalent/divalent ion solutions from their sequences. As compared with the extensive experimental data and available existing models, we showed that the present model can successfully fold simple DNAs into their native-like structures, and can also accurately reproduce the effects of sequence and monovalent/divalent ions on structure stability for ssDNAs including pseudoknot and dsDNAs with/without bulge/internal loops.
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Affiliation(s)
- Zi-Chun Mu
- Research Center of Nonlinear Science, School of Mathematical & Physical Sciences, Wuhan Textile University, Wuhan, China
- School of Computer Science and Artificial Intelligence, Wuhan Textile University, Wuhan, China
| | - Ya-Lan Tan
- Research Center of Nonlinear Science, School of Mathematical & Physical Sciences, Wuhan Textile University, Wuhan, China
| | - Ben-Gong Zhang
- Research Center of Nonlinear Science, School of Mathematical & Physical Sciences, Wuhan Textile University, Wuhan, China
| | - Jie Liu
- Research Center of Nonlinear Science, School of Mathematical & Physical Sciences, Wuhan Textile University, Wuhan, China
| | - Ya-Zhou Shi
- Research Center of Nonlinear Science, School of Mathematical & Physical Sciences, Wuhan Textile University, Wuhan, China
- * E-mail:
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13
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Huisjes NM, Retzer TM, Scherr MJ, Agarwal R, Rajappa L, Safaric B, Minnen A, Duderstadt KE. Mars, a molecule archive suite for reproducible analysis and reporting of single-molecule properties from bioimages. eLife 2022; 11:75899. [PMID: 36098381 PMCID: PMC9470159 DOI: 10.7554/elife.75899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 08/19/2022] [Indexed: 11/16/2022] Open
Abstract
The rapid development of new imaging approaches is generating larger and more complex datasets, revealing the time evolution of individual cells and biomolecules. Single-molecule techniques, in particular, provide access to rare intermediates in complex, multistage molecular pathways. However, few standards exist for processing these information-rich datasets, posing challenges for wider dissemination. Here, we present Mars, an open-source platform for storing and processing image-derived properties of biomolecules. Mars provides Fiji/ImageJ2 commands written in Java for common single-molecule analysis tasks using a Molecule Archive architecture that is easily adapted to complex, multistep analysis workflows. Three diverse workflows involving molecule tracking, multichannel fluorescence imaging, and force spectroscopy, demonstrate the range of analysis applications. A comprehensive graphical user interface written in JavaFX enhances biomolecule feature exploration by providing charting, tagging, region highlighting, scriptable dashboards, and interactive image views. The interoperability of ImageJ2 ensures Molecule Archives can easily be opened in multiple environments, including those written in Python using PyImageJ, for interactive scripting and visualization. Mars provides a flexible solution for reproducible analysis of image-derived properties, facilitating the discovery and quantitative classification of new biological phenomena with an open data format accessible to everyone.
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Affiliation(s)
- Nadia M Huisjes
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Thomas M Retzer
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Martinsried, Germany.,Physik Department, Technische Universität München, Garching, Germany
| | - Matthias J Scherr
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Rohit Agarwal
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Martinsried, Germany.,Physik Department, Technische Universität München, Garching, Germany
| | - Lional Rajappa
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Barbara Safaric
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Anita Minnen
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Karl E Duderstadt
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Martinsried, Germany.,Physik Department, Technische Universität München, Garching, Germany
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14
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Segers M, Voorspoels A, Sakaue T, Carlon E. Mechanical properties of nucleic acids and the non-local twistable wormlike chain model. J Chem Phys 2022; 156:234105. [PMID: 35732531 DOI: 10.1063/5.0089166] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Mechanical properties of nucleic acids play an important role in many biological processes that often involve physical deformations of these molecules. At sufficiently long length scales (say, above ∼20-30 base pairs), the mechanics of DNA and RNA double helices is described by a homogeneous Twistable Wormlike Chain (TWLC), a semiflexible polymer model characterized by twist and bending stiffnesses. At shorter scales, this model breaks down for two reasons: the elastic properties become sequence-dependent and the mechanical deformations at distal sites get coupled. We discuss in this paper the origin of the latter effect using the framework of a non-local Twistable Wormlike Chain (nlTWLC). We show, by comparing all-atom simulations data for DNA and RNA double helices, that the non-local couplings are of very similar nature in these two molecules: couplings between distal sites are strong for tilt and twist degrees of freedom and weak for roll. We introduce and analyze a simple double-stranded polymer model that clarifies the origin of this universal distal couplings behavior. In this model, referred to as the ladder model, a nlTWLC description emerges from the coarsening of local (atomic) degrees of freedom into angular variables that describe the twist and bending of the molecule. Different from its local counterpart, the nlTWLC is characterized by a length-scale-dependent elasticity. Our analysis predicts that nucleic acids are mechanically softer at the scale of a few base pairs and are asymptotically stiffer at longer length scales, a behavior that matches experimental data.
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Affiliation(s)
- Midas Segers
- Soft Matter and Biophysics Unit, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - Aderik Voorspoels
- Soft Matter and Biophysics Unit, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - Takahiro Sakaue
- Department of Physical Sciences, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara 252-5258, Kanagawa, Japan
| | - Enrico Carlon
- Soft Matter and Biophysics Unit, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
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15
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Nord AL, Biquet-Bisquert A, Abkarian M, Pigaglio T, Seduk F, Magalon A, Pedaci F. Dynamic stiffening of the flagellar hook. Nat Commun 2022; 13:2925. [PMID: 35614041 PMCID: PMC9133114 DOI: 10.1038/s41467-022-30295-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 04/22/2022] [Indexed: 11/09/2022] Open
Abstract
For many bacteria, motility stems from one or more flagella, each rotated by the bacterial flagellar motor, a powerful rotary molecular machine. The hook, a soft polymer at the base of each flagellum, acts as a universal joint, coupling rotation between the rigid membrane-spanning rotor and rigid flagellum. In multi-flagellated species, where thrust arises from a hydrodynamically coordinated flagellar bundle, hook flexibility is crucial, as flagella rotate significantly off-axis. However, consequently, the thrust applies a significant bending moment. Therefore, the hook must simultaneously be compliant to enable bundle formation yet rigid to withstand large hydrodynamical forces. Here, via high-resolution measurements and analysis of hook fluctuations under dynamical conditions, we elucidate how it fulfills this double functionality: the hook shows a dynamic increase in bending stiffness under increasing torsional stress. Such strain-stiffening allows the system to be flexible when needed yet reduce deformation under high loads, enabling high speed motility. Bacterial motility relies on the mechanics of the “hook” the 60 nm biopolymer at the base of rotating flagella. Here, authors observe the hook stiffening as it is twisted by the rotation of the flagellum, a mechanical feat evolved for its function.
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Affiliation(s)
- Ashley L Nord
- Centre de Biologie Structurale, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Anaïs Biquet-Bisquert
- Centre de Biologie Structurale, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Manouk Abkarian
- Centre de Biologie Structurale, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Théo Pigaglio
- Aix Marseille Université, CNRS, Laboratoire de Chimie Bactérienne (UMR7283), IMM, IM2B, 13402, Marseille, France
| | - Farida Seduk
- Aix Marseille Université, CNRS, Laboratoire de Chimie Bactérienne (UMR7283), IMM, IM2B, 13402, Marseille, France
| | - Axel Magalon
- Aix Marseille Université, CNRS, Laboratoire de Chimie Bactérienne (UMR7283), IMM, IM2B, 13402, Marseille, France
| | - Francesco Pedaci
- Centre de Biologie Structurale, Univ. Montpellier, CNRS, INSERM, Montpellier, France.
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16
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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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17
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Chhetri KB, Sharma A, Naskar S, Maiti PK. Nanoscale structures and mechanics of peptide nucleic acids. NANOSCALE 2022; 14:6620-6635. [PMID: 35421892 DOI: 10.1039/d1nr04239d] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Peptide nucleic acids (PNAs) are charge-neutral polyamide oligomers having extremely favorable thermal stability and high affinity to cell membranes when coupled with cationic cell-penetrating peptides (CPPs), as well as the encouraging antisense and antigene activity in cell-free systems. The study of the mechanical properties of short PNA molecules is rare both in experiments and theoretical calculations. Here, we studied the microscopic structures and elastic properties; namely, persistence length, stretch modulus, twist-stretch coupling, and structural crookedness of double-stranded PNA (dsPNA) and their hybrid derivatives using all-atom MD simulation and compared them with those of double-stranded DNA (dsDNA) and double-stranded RNA (dsRNA). The stretch modulus of the dsPNA is found to be ∼160 pN, an order of magnitude lower than that of dsDNA and smaller than dsRNA, respectively. Similarly, the persistence length of dsPNA is found to be ∼35 nm, significantly smaller than those of dsDNA and dsRNA. The PNA-DNA and PNA-RNA hybrid duplexes have elastic properties lying between that of dsPNA and dsDNA/dsRNA. We argue that the neutral backbones of the PNA make it less stiff than dsDNA and dsRNA molecules. Measurement of structural crookedness and principal component analysis additionally support the bending flexibility of dsPNA. Detailed analysis of the helical-rise coupled to helical-twist indicates that the PNA-DNA hybrid over-winds like dsDNA, while PNA-PNA and PNA-RNA unwind like dsRNA upon stretching. Because of the highly flexible nature of PNA, it can bind other biomolecules by adopting a wide range of conformations and is believed to be crucial for future nanobiotechnology research studies.
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Affiliation(s)
- Khadka B Chhetri
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India.
- Department of Physics, Prithvinarayan Campus, Tribhuvan University, Nepal
| | - Akshara Sharma
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India.
| | - 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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18
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Chhetri KB, Dasgupta C, Maiti PK. Diameter Dependent Melting and Softening of dsDNA Under Cylindrical Confinement. Front Chem 2022; 10:879746. [PMID: 35586267 PMCID: PMC9108266 DOI: 10.3389/fchem.2022.879746] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 04/08/2022] [Indexed: 11/13/2022] Open
Abstract
Carbon nanotubes (CNTs) are considered promising candidates for biomolecular confinement, including DNA encapsulation for gene delivery. Threshold values of diameters have been reported for double-stranded DNA (dsDNA) encapsulation inside CNTs. We have performed all-atom molecular dynamics (MD) simulations of dsDNAs confined inside single-walled CNTs (SWCNTs) at the physiologically relevant temperature of 300 K. We found that the dsDNA can be confined without being denatured only when the diameter of the SWCNT exceeds a threshold value. Below this threshold diameter, the dsDNA gets denatured and melts even at the temperature of 300 K. Our simulations using SWCNTs with chirality indices (20,20) to (30,30) at 300 K found the critical diameter to be 3.25 nm (corresponding to (24,24) chirality). Analyses of the hydrogen bonds (H-bonds), Van der Walls (VdW) energy, and other inter-base interactions show drastic reduction in the number of H-bonds, VdW energy, and electrostatic energies between the bases of dsDNA when it is confined in narrower SWCNTs (up to diameter of 3.12 nm). On the other hand, the higher interaction energy between the dsDNA and the SWCNT surface in narrower SWCNTs assists in the melting of the dsDNA. Electrostatic mapping and hydration status analyses show that the dsDNA is not adequately hydrated and the counter ion distribution is not uniform below the critical diameter of the SWCNT. As properly hydrated counter ions provide stability to the dsDNA, we infer that the inappropriate hydration of counter ions and their non-uniform distribution around the dsDNA cause the melting of the dsDNA inside SWCNTs of diameter below the critical value of 3.25 nm. For confined dsDNAs that do not get denatured, we computed their elastic properties. The persistence length of dsDNA was found to increase by a factor of about two and the torsional stiffness by a factor of 1.5 for confinement inside SWCNTs of diameters up to 3.79 nm, the stretch modulus also following nearly the same trend. Interestingly, for higher diameters of SWCNT, 3.79 nm and above, the dsDNA becomes more flexible, demonstrating that the mechanical properties of the dsDNA under cylindrical confinement depend non-monotonically on the confinement diameter.
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Affiliation(s)
- Khadka B. Chhetri
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore, India
- Department of Physics, Prithvinarayan Campus, Tribhuvan University, Pokhara, Nepal
| | - Chandan Dasgupta
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore, India
| | - Prabal K. Maiti
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore, India
- *Correspondence: Prabal K. Maiti,
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19
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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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20
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Qiang XW, Zhang C, Dong HL, Tian FJ, Fu H, Yang YJ, Dai L, Zhang XH, Tan ZJ. Multivalent Cations Reverse the Twist-Stretch Coupling of RNA. PHYSICAL REVIEW LETTERS 2022; 128:108103. [PMID: 35333091 DOI: 10.1103/physrevlett.128.108103] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 02/10/2022] [Indexed: 06/14/2023]
Abstract
When stretched, both DNA and RNA duplexes change their twist angles through twist-stretch coupling. The coupling is negative for DNA but positive for RNA, which is not yet completely understood. Here, our magnetic tweezers experiments show that the coupling of RNA reverses from positive to negative by multivalent cations. Combining with the previously reported tension-induced negative-to-positive coupling reversal of DNA, we propose a unified mechanism of the couplings of both RNA and DNA based on molecular dynamics simulations. Two deformation pathways are competing when stretched: shrinking the radius causes positive couplings but widening the major groove causes negative couplings. For RNA whose major groove is clamped by multivalent cations and canonical DNA, their radii shrink when stretched, thus exhibiting positive couplings. For elongated DNA whose radius already shrinks to the minimum and canonical RNA, their major grooves are widened when stretched, thus exhibiting negative couplings.
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Affiliation(s)
- Xiao-Wei Qiang
- Department of Physics and Key Laboratory of Artificial Micro & Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - 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
| | - Hai-Long Dong
- Department of Physics and Key Laboratory of Artificial Micro & Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Fu-Jia Tian
- Department of Physics, City University of Hong Kong, Hong Kong 999077, China
| | - Hang Fu
- 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
| | - Ya-Jun Yang
- 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
| | - 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
| | - Zhi-Jie Tan
- Department of Physics and Key Laboratory of Artificial Micro & Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China
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21
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Kim M, Hong CC, Lee S, Kim JS. Dynamics of a
DNA
minicircle: Poloidal rotation and in‐plane circular vibration. B KOREAN CHEM SOC 2022. [DOI: 10.1002/bkcs.12492] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Minjung Kim
- Department of Chemistry and Nanoscience Ewha Womans University Seoul South Korea
| | - Chi Cheng Hong
- Department of Chemistry and Nanoscience Ewha Womans University Seoul South Korea
- School of Chemistry University of Edinburgh Edinburgh UK
| | - Saeyeon Lee
- Department of Chemistry and Nanoscience Ewha Womans University Seoul South Korea
| | - Jun Soo Kim
- Department of Chemistry and Nanoscience Ewha Womans University Seoul South Korea
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22
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Kim M, Bae S, Oh I, Yoo J, Kim JS. Sequence-dependent twist-bend coupling in DNA minicircles. NANOSCALE 2021; 13:20186-20196. [PMID: 34847218 DOI: 10.1039/d1nr04672a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Looping of double-stranded DNA molecules with 100-200 base pairs into minicircles, catenanes, and rotaxanes has been suggested as a potential tool for DNA nanotechnologies. However, sharp DNA bending into a minicircle with a diameter of several to ten nanometers occurs with alterations in the DNA helical structure and may lead to defective kink formation that hampers the use of DNA minicircles, catenanes, and rotaxanes in nanoscale DNA applications. Here, we investigated local variations of a helical twist in sharply bent DNA using microsecond-long all-atom molecular dynamics simulations of six different DNA minicircles, focusing on the sequence dependence of the coupling between DNA bending and its helical twist. Twist angles between consecutive base pairs were analyzed at different locations relative to the direction of DNA bending and, among 10 unique dinucleotide steps, we identified four dinucleotide steps with strong twist-bend coupling, the pyrimidine-purine dinucleotide steps of TA/TA, CG/CG, and CA/TG and the purine-purine dinucleotide step of GA/TC. This work suggests the sequence-dependent structural responses of DNA to strong mechanical deformation, providing new molecular-level insights into the structure and stability of sharply bent DNA minicircles for nanoscale applications.
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Affiliation(s)
- Minjung Kim
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul 03760, Republic of Korea.
| | - Sehui Bae
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul 03760, Republic of Korea.
| | - Inrok Oh
- LG Chem Ltd, LG Science Park, Seoul 07796, Republic of Korea
| | - Jejoong Yoo
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jun Soo Kim
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul 03760, Republic of Korea.
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23
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KOH HEEYUEN, LEE JAEGYUNG, LEE JAEYOUNG, KIM RYAN, TABATA OSAMU, JIN-WOO KIM, KIM DONYUN. Design Approaches and Computational Tools for DNA Nanostructures. IEEE OPEN JOURNAL OF NANOTECHNOLOGY 2021; 2:86-100. [PMID: 35756857 PMCID: PMC9232119 DOI: 10.1109/ojnano.2021.3119913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Designing a structure in nanoscale with desired shape and properties has been enabled by structural DNA nanotechnology. Design strategies in this research field have evolved to interpret various aspects of increasingly more complex nanoscale assembly and to realize molecular-level functionality by exploring static to dynamic characteristics of the target structure. Computational tools have naturally been of significant interest as they are essential to achieve a fine control over both shape and physicochemical properties of the structure. Here, we review the basic design principles of structural DNA nanotechnology together with its computational analysis and design tools.
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Affiliation(s)
- HEEYUEN KOH
- Institute of Advanced Machines and Design, Seoul National University, Seoul 08826, Republic of Korea
| | - JAE GYUNG LEE
- Department of Mechanical Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - JAE YOUNG LEE
- Institute of Advanced Machines and Design, Seoul National University, Seoul 08826, Republic of Korea
| | - RYAN KIM
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138 USA
- Bio/Nano Technology Group, Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR 72701 USA
| | - OSAMU TABATA
- Faculty of Engineering, Kyoto University of Advanced Science, Kyoto 621-8555, Japan
| | - KIM JIN-WOO
- Bio/Nano Technology Group, Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR 72701 USA
- Department of Biological and Agricultural Engineering, University of Arkansas, Fayetteville, AR 72701 USA
- Materials Science and Engineering Program, University of Arkansas, Fayetteville, AR 72701 USA
| | - DO-NYUN KIM
- Institute of Advanced Machines and Design, Seoul National University, Seoul 08826, Republic of Korea
- Department of Mechanical Engineering, Seoul National University, Seoul 08826, Republic of Korea
- Institute of Engineering Research, Seoul National University, Seoul 08826, Republic of Korea
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24
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Dohnalová H, Lankaš F. Deciphering the mechanical properties of
B‐DNA
duplex. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2021. [DOI: 10.1002/wcms.1575] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Hana Dohnalová
- Department of Informatics and Chemistry University of Chemistry and Technology Prague Praha 6 Czech Republic
| | - Filip Lankaš
- Department of Informatics and Chemistry University of Chemistry and Technology Prague Praha 6 Czech Republic
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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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26
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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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27
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Xu W, Dunlap D, Finzi L. Energetics of twisted DNA topologies. Biophys J 2021; 120:3242-3252. [PMID: 33974883 DOI: 10.1016/j.bpj.2021.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 03/30/2021] [Accepted: 05/05/2021] [Indexed: 11/30/2022] Open
Abstract
Our goal is to review the main theoretical models used to calculate free energy changes associated with common, torsion-induced conformational changes in DNA and provide the resulting equations hoping to facilitate quantitative analysis of both in vitro and in vivo studies. This review begins with a summary of work regarding the energy change of the negative supercoiling-induced B- to L-DNA transition, followed by a discussion of the energetics associated with the transition to Z-form DNA. Finally, it describes the energy changes associated with the formation of DNA curls and plectonemes, which can regulate DNA-protein interactions and promote cross talk between distant DNA elements, respectively. The salient formulas and parameters for each scenario are summarized in table format to facilitate comparison and provide a concise, user-friendly resource.
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Affiliation(s)
- Wenxuan Xu
- Emory University, Department of Physics, Atlanta, Georgia
| | - David Dunlap
- Emory University, Department of Physics, Atlanta, Georgia
| | - Laura Finzi
- Emory University, Department of Physics, Atlanta, Georgia.
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28
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Skoruppa E, Voorspoels A, Vreede J, Carlon E. Length-scale-dependent elasticity in DNA from coarse-grained and all-atom models. Phys Rev E 2021; 103:042408. [PMID: 34005944 DOI: 10.1103/physreve.103.042408] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 03/25/2021] [Indexed: 12/24/2022]
Abstract
We investigate the influence of nonlocal couplings on the torsional and bending elasticities of DNA. Such couplings have been observed in the past by several simulation studies. Here, we use a description of DNA conformations based on the variables tilt, roll, and twist. Our analysis of both coarse-grained (oxDNA) and all-atom models indicates that these share strikingly similar features: there are strong off-site couplings for tilt-tilt and twist-twist, while they are much weaker in the roll-roll case. By developing an analytical framework to estimate bending and torsional persistence lengths in nonlocal DNA models, we show how off-site interactions generate a length-scale-dependent elasticity. Based on the simulation-generated elasticity data, the theory predicts a significant length-scale-dependent effect on torsional fluctuations but only a modest effect on bending fluctuations. These results are in agreement with experiments probing DNA mechanics from single base pair to kilobase pair scales.
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Affiliation(s)
- Enrico Skoruppa
- Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - Aderik Voorspoels
- Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - Jocelyne Vreede
- Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, the Netherlands
| | - Enrico Carlon
- Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
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29
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A quantitative model of a cooperative two-state equilibrium in DNA: experimental tests, insights, and predictions. Q Rev Biophys 2021; 54:e5. [PMID: 33722316 DOI: 10.1017/s0033583521000032] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Quantitative parameters for a two-state cooperative transition in duplex DNAs were finally obtained during the last 5 years. After a brief discussion of observations pertaining to the existence of the two-state equilibrium per se, the lengths, torsion, and bending elastic constants of the two states involved and the cooperativity parameter of the model are simply stated. Experimental tests of model predictions for the responses of DNA to small applied stretching, twisting, and bending stresses, and changes in temperature, ionic conditions, and sequence are described. The mechanism and significance of the large cooperativity, which enables significant DNA responses to such small perturbations, are also noted. The capacity of the model to resolve a number of long-standing and sometimes interconnected puzzles in the extant literature, including the origin of the broad pre-melting transition studied by numerous workers in the 1960s and 1970s, is demonstrated. Under certain conditions, the model predicts significant long-range attractive or repulsive interactions between hypothetical proteins with strong preferences for one or the other state that are bound to well-separated sites on the same DNA. A scenario is proposed for the activation of the ilvPG promoter on a supercoiled DNA by integration host factor.
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30
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Nonequilibrium dynamics and action at a distance in transcriptionally driven DNA supercoiling. Proc Natl Acad Sci U S A 2021; 118:1905215118. [PMID: 33649196 DOI: 10.1073/pnas.1905215118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
We study the effect of transcription on the kinetics of DNA supercoiling in three dimensions by means of Brownian dynamics simulations of a single-nucleotide-resolution coarse-grained model for double-stranded DNA. By explicitly accounting for the action of a transcribing RNA polymerase (RNAP), we characterize the geometry and nonequilibrium dynamics of the ensuing twin supercoiling domains. Contrary to the typical textbook picture, we find that the generation of twist by RNAP results in the formation of plectonemes (writhed DNA) some distance away. We further demonstrate that this translates into an "action at a distance" on DNA-binding proteins; for instance, positive supercoils downstream of an elongating RNAP destabilize nucleosomes long before the transcriptional machinery reaches the histone octamer. We also analyze the relaxation dynamics of supercoiled double-stranded DNA, and characterize the widely different timescales of twist diffusion, which is a simple and fast process, and writhe relaxation, which is much slower and entails multiple steps.
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31
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Zhou Z. Bistability induced by a spontaneous twisting rate for a two-dimensional intrinsically curved filament. Phys Rev E 2021; 103:012410. [PMID: 33601634 DOI: 10.1103/physreve.103.012410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 01/06/2021] [Indexed: 11/07/2022]
Abstract
We find that a moderate intrinsic twisting rate (ITR) can induce a bistable state for a force-free two-dimensional intrinsically curved filament. There are two different configurations of equal energy in a bistable state so that the filament is clearly different from its three-dimensional counterpart. The smaller the ITR or the larger the intrinsic curvature (IC), the clearer the distinction between two isoenergetic configurations and the longer the filament. In bistable states, the relationship between length and ITR is approximately a hyperbola and relationship between IC and critical ITR is approximately linear. Thermal fluctuation can result in a shift between two isoenergetic configurations, but large bending and twisting rigidities can prevent the shift and maintain the filament in one of these two configurations. Moreover, a filament can have a metastable state and at a finite temperature such a filament has the similar property as that of a filament with bistable state.
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Affiliation(s)
- Zicong Zhou
- Department of Physics, Tamkang University, New Taipei City, 25137 Taiwan, Republic of China
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32
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Gutiérrez Fosado YA, Landuzzi F, Sakaue T. Twist dynamics and buckling instability of ring DNA: the effect of groove asymmetry and anisotropic bending. SOFT MATTER 2021; 17:1530-1537. [PMID: 33331374 DOI: 10.1039/d0sm01812k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
By combining analytical theory and Molecular Dynamics simulations we study the relaxation dynamics of DNA circular plasmids that initially undergo a local twist perturbation. In this process, the twist-bend coupling arising from the groove asymmetry in the DNA double helix clearly shows up. In the two scenarios explored, with/without this coupling, the initial perturbation relaxes diffusively. However, there are some marked differences in the value of the diffusion coefficient and the dynamics in both cases. These differences can be explained by assuming the existence of three distinctive time scales; a rapid relaxation of local bending, the slow twist spreading, and the buckling transition taking place in a much longer time scale. In particular, the separation of time scales allows deducing an effective diffusion equation in stage , with a diffusion coefficient influenced by the twist-bend coupling. We also discuss the mapping of the realistic DNA model to the simpler isotropic twistable worm-like chain using the renormalized bending and twist moduli; although useful in many cases, it fails to make a quantitative prediction on the instability mode of buckling transition.
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Affiliation(s)
- Yair Augusto Gutiérrez Fosado
- Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara-shi, Kanagawa 252-5258, Japan.
| | - Fabio Landuzzi
- Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara-shi, Kanagawa 252-5258, Japan.
| | - Takahiro Sakaue
- Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara-shi, Kanagawa 252-5258, Japan. and PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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33
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Desai PR, Brahmachari S, Marko JF, Das S, Neuman KC. Coarse-grained modelling of DNA plectoneme pinning in the presence of base-pair mismatches. Nucleic Acids Res 2020; 48:10713-10725. [PMID: 33045724 DOI: 10.1093/nar/gkaa836] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 09/14/2020] [Accepted: 09/18/2020] [Indexed: 12/27/2022] Open
Abstract
Damaged or mismatched DNA bases result in the formation of physical defects in double-stranded DNA. In vivo, defects in DNA must be rapidly and efficiently repaired to maintain cellular function and integrity. Defects can also alter the mechanical response of DNA to bending and twisting constraints, both of which are important in defining the mechanics of DNA supercoiling. Here, we use coarse-grained molecular dynamics (MD) simulation and supporting statistical-mechanical theory to study the effect of mismatched base pairs on DNA supercoiling. Our simulations show that plectoneme pinning at the mismatch site is deterministic under conditions of relatively high force (>2 pN) and high salt concentration (>0.5 M NaCl). Under physiologically relevant conditions of lower force (0.3 pN) and lower salt concentration (0.2 M NaCl), we find that plectoneme pinning becomes probabilistic and the pinning probability increases with the mismatch size. These findings are in line with experimental observations. The simulation framework, validated with experimental results and supported by the theoretical predictions, provides a way to study the effect of defects on DNA supercoiling and the dynamics of supercoiling in molecular detail.
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Affiliation(s)
- Parth Rakesh Desai
- Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA.,Laboratory of Single Molecule Biophysics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | | | - John F Marko
- Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208, USA.,Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Siddhartha Das
- Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA
| | - Keir C Neuman
- Laboratory of Single Molecule Biophysics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
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34
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Chhabra H, Mishra G, Cao Y, Prešern D, Skoruppa E, Tortora MMC, Doye JPK. Computing the Elastic Mechanical Properties of Rodlike DNA Nanostructures. J Chem Theory Comput 2020; 16:7748-7763. [PMID: 33164531 DOI: 10.1021/acs.jctc.0c00661] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
To study the elastic properties of rodlike DNA nanostructures, we perform long simulations of these structures using the oxDNA coarse-grained model. By analyzing the fluctuations in these trajectories, we obtain estimates of the bend and twist persistence lengths and the underlying bend and twist elastic moduli and couplings between them. Only on length scales beyond those associated with the spacings between the interhelix crossovers do the bending fluctuations behave like those of a wormlike chain. The obtained bending persistence lengths are much larger than that for double-stranded DNA and increase nonlinearly with the number of helices, whereas the twist moduli increase approximately linearly. To within the numerical error in our data, the twist-bend coupling constants are of order zero. That the bending persistence lengths that we obtain are generally somewhat higher than in experiment probably reflects both that the simulated origamis have no assembly defects and that the oxDNA extensional modulus for double-stranded DNA is too large.
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Affiliation(s)
- Hemani Chhabra
- Physical & Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Garima Mishra
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Yijing Cao
- Physical & Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Domen Prešern
- Physical & Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Enrico Skoruppa
- Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - Maxime M C Tortora
- Physical & Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom.,Laboratory of Biology and Modeling of the Cell, École Normale Supérieure de Lyon, 46, allée d'Italie, 69364 Lyon Cedex 07, France
| | - Jonathan P K Doye
- Physical & Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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35
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Engel MC, Romano F, Louis AA, Doye JPK. Measuring Internal Forces in Single-Stranded DNA: Application to a DNA Force Clamp. J Chem Theory Comput 2020; 16:7764-7775. [PMID: 33147408 DOI: 10.1021/acs.jctc.0c00286] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We present a new method for calculating internal forces in DNA structures using coarse-grained models and demonstrate its utility with the oxDNA model. The instantaneous forces on individual nucleotides are explored and related to model potentials, and using our framework, internal forces are calculated for two simple DNA systems and for a recently published nanoscopic force clamp. Our results highlight some pitfalls associated with conventional methods for estimating internal forces, which are based on elastic polymer models, and emphasize the importance of carefully considering secondary structure and ionic conditions when modeling the elastic behavior of single-stranded DNA. Beyond its relevance to the DNA nanotechnological community, we expect our approach to be broadly applicable to calculations of internal force in a variety of structures-from DNA to protein-and across other coarse-grained simulation models.
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Affiliation(s)
- Megan C Engel
- School of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, Massachusetts 02138, United States.,Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford, OX1 3NP, U.K
| | - Flavio Romano
- Dipartimento di Scienze Molecolari e Nanosistemi, Universitá Ca Foscari di Venezia, Via Torino 155, 30172, Venezia Mestre, Italy
| | - Ard A Louis
- Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford, OX1 3NP, U.K
| | - Jonathan P K Doye
- Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QZ, U.K
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36
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Chevizovich D, Michieletto D, Mvogo A, Zakiryanov F, Zdravković S. A review on nonlinear DNA physics. ROYAL SOCIETY OPEN SCIENCE 2020; 7:200774. [PMID: 33391787 PMCID: PMC7735367 DOI: 10.1098/rsos.200774] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 10/23/2020] [Indexed: 06/12/2023]
Abstract
The study and the investigation of structural and dynamical properties of complex systems have attracted considerable interest among scientists in general and physicists and biologists in particular. The present review paper represents a broad overview of the research performed over the nonlinear dynamics of DNA, devoted to some different aspects of DNA physics and including analytical, quantum and computational tools to understand nonlinear DNA physics. We review in detail the semi-discrete approximation within helicoidal Peyrard-Bishop model and show that localized modulated solitary waves, usually called breathers, can emerge and move along the DNA. Since living processes occur at submolecular level, we then discuss a quantum treatment to address the problem of how charge and energy are transported on DNA and how they may play an important role for the functioning of living cells. While this problem has attracted the attention of researchers for a long time, it is still poorly understood how charge and energy transport can occur at distances comparable to the size of macromolecules. Here, we review a theory based on the mechanism of 'self-trapping' of electrons due to their interaction with mechanical (thermal) oscillation of the DNA structure. We also describe recent computational models that have been developed to capture nonlinear mechanics of DNA in vitro and in vivo, possibly under topological constraints. Finally, we provide some conjectures on potential future directions for this field.
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Affiliation(s)
- Dalibor Chevizovich
- Institut za nuklearne nauke Vinča, Univerzitet u Beogradu, 11001 Beograd, Serbia
| | - Davide Michieletto
- School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK
| | - Alain Mvogo
- Laboratory of Biophysics, Department of Physics, Faculty of Science, University of Yaounde I, PO Box 812, Cameroon
| | - Farit Zakiryanov
- Bashkir State University, 32 Zali Validi Street, 450076 Ufa, Republic of Bashkortostan, Russia
| | - Slobodan Zdravković
- Institut za nuklearne nauke Vinča, Univerzitet u Beogradu, 11001 Beograd, Serbia
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37
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Zhou Z. Crucial role of the intrinsic twist rate for the size of an intrinsically curved semiflexible biopolymer. Phys Rev E 2020; 102:032405. [PMID: 33075885 DOI: 10.1103/physreve.102.032405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/24/2020] [Indexed: 02/03/2023]
Abstract
We study the effects of the intrinsic curvature (IC), intrinsic twist rate (ITR), anisotropic bending rigidities, sequence disorder, and temperature (T) on the persistence length (l_{p}) of a two- or three-dimensional semiflexible biopolymer. We develop some general expressions to evaluate exactly these effects. We find that a moderate IC alone reduces l_{p} considerably. Our results indicate that the centerline of the filament keeps as a helix in a rather large range of T when ITR is small. However, a large ITR can counterbalance the effect of IC and the result is insensitive to the twist rigidity. Moreover, a weak randomness in IC and ITR can result in an "overexpanded" state. Meanwhile, when ITR is small, l_{p} is not a monotonic function of T but can have either minimum or maximum at some T, and in the two-dimensional case the maximum is more obvious than that in the three-dimensional case. These results reveal that to obtain a proper size at a finite T for an intrinsically curved semiflexible biopolymer, proper values of bending rigidities and ITR are necessary but a large twist rigidity may be only a by-product. Our findings are instructive in controlling the size of a semiflexible biopolymer in organic synthesis since the mean end-to-end distance and radius of gyration of a long semiflexible biopolymer are proportional to l_{p}.
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Affiliation(s)
- Zicong Zhou
- Department of Physics, Tamkang University, New Taipei City, 25137 Taiwan, Republic of China
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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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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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40
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Statistical physics and mesoscopic modeling to interpret tethered particle motion experiments. Methods 2019; 169:57-68. [PMID: 31302177 DOI: 10.1016/j.ymeth.2019.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/11/2019] [Accepted: 07/07/2019] [Indexed: 11/22/2022] Open
Abstract
Tethered particle motion experiments are versatile single-molecule techniques enabling one to address in vitro the molecular properties of DNA and its interactions with various partners involved in genetic regulations. These techniques provide raw data such as the tracked particle amplitude of movement, from which relevant information about DNA conformations or states must be recovered. Solving this inverse problem appeals to specific theoretical tools that have been designed in the two last decades, together with the data pre-processing procedures that ought to be implemented to avoid biases inherent to these experimental techniques. These statistical tools and models are reviewed in this paper.
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41
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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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42
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Najafi S. Irreversible topological transition of a stretched superhelix: the interplay of chiralities. SOFT MATTER 2019; 15:6258-6262. [PMID: 31338508 DOI: 10.1039/c9sm01027k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Helical complexes with certain intramolecular constraints on their topological state, exhibit nontrivial conformational changes in response to an external tension. We consider a generic right-handed helix and construct identical right and left-handed superhelixes. By using molecular dynamics simulations, we discover that under an external tension, the interplay between the helix chirality and the chirality of the superhelix leads to a fundamental topology transition of the stretched right-handed superhelix to its left-handed counterpart. We characterize and rationalize this irreversible phenomenon for a wide range of intramolecular angular stiffnesses and determine the associated phase diagram at different external loadings.
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Affiliation(s)
- Saeed Najafi
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
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43
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Temperature-dependence of the bending elastic constant of DNA and extension of the two-state model. Tests and new insights. Biophys Chem 2019; 251:106146. [DOI: 10.1016/j.bpc.2019.106146] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 03/28/2019] [Accepted: 04/01/2019] [Indexed: 12/15/2022]
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44
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Schurr JM. Effects of Sequence Changes on the Torsion Elastic Constant and Persistence Length of DNA. Applications of the Two-State Model. J Phys Chem B 2019; 123:7343-7353. [DOI: 10.1021/acs.jpcb.9b05139] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- J. Michael Schurr
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195, United States
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45
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Nomidis SK, Caraglio M, Laleman M, Phillips K, Skoruppa E, Carlon E. Twist-bend coupling, twist waves, and the shape of DNA loops. Phys Rev E 2019; 100:022402. [PMID: 31574750 DOI: 10.1103/physreve.100.022402] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Indexed: 06/10/2023]
Abstract
By combining analytical and numerical calculations, we investigate the minimal-energy shape of short DNA loops of approximately 100 base pairs (bp). We show that in these loops the excess twist density oscillates as a response to an imposed bending stress, as recently found in DNA minicircles and observed in nucleosomal DNA. These twist oscillations, here referred to as twist waves, are due to the coupling between twist and bending deformations, which in turn originates from the asymmetry between DNA major and minor grooves. We introduce a simple analytical variational shape that reproduces the exact loop energy up to the fourth significant digit and is in very good agreement with shapes obtained from coarse-grained simulations. We, finally, analyze the loop dynamics at room temperature, and show that the twist waves are robust against thermal fluctuations. They perform a normal diffusive motion, whose origin is briefly discussed.
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Affiliation(s)
- S K Nomidis
- Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
- Flemish Institute for Technological Research (VITO), Boeretang 200, B-2400 Mol, Belgium
| | - M Caraglio
- Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
- Institut für Theoretische Physik, Universität Innsbruck, Technikerstraße 21A, A-6020 Innsbruck, Austria
| | - M Laleman
- Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - K Phillips
- Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - E Skoruppa
- Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - E Carlon
- Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
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Kosuri P, Altheimer BD, Dai M, Yin P, Zhuang X. Rotation tracking of genome-processing enzymes using DNA origami rotors. Nature 2019; 572:136-140. [PMID: 31316204 PMCID: PMC7036295 DOI: 10.1038/s41586-019-1397-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 06/17/2019] [Indexed: 11/24/2022]
Abstract
Many genome-processing reactions, such as transcription, replication and repair, generate DNA rotation. Methods that directly measure DNA rotation, including rotor bead tracking1–3, angular optical trap4, and magnetic tweezers5 have helped unravel the action mechanisms of a range of genome-processing enzymes, such as RNA polymerase (RNAP)6, gyrase2, viral DNA packaging motor7, and DNA recombination enzymes8. However, despite the potential of rotation measurements to transform our understanding of genome-processing reactions, measuring DNA rotation remains a difficult task. The time resolution of existing methods is insufficient to track rotation induced by many enzymes under physiological conditions, and the measurement throughput is typically low. Here we introduce Origami-Rotor-Based Imaging and Tracking (ORBIT), a method that uses fluorescently labeled DNA origami rotors to track DNA rotation at the single-molecule level with millisecond time resolution. We used ORBIT to track DNA rotation resulted from unwinding by RecBCD, a helicase involved in DNA repair9, and transcription by RNAP. We characterized a series of events during RecBCD-induced DNA unwinding, including initiation, processive translocation, pausing and backtracking, and revealed an initiation mechanism that involves reversible, ATP-independent DNA unwinding and engagement of the RecB motor. During transcription by RNAP, we directly observed rotational steps corresponding to single-base-pair unwinding. We envision ORBIT will enable studies of a wide range of protein-DNA interactions.
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Affiliation(s)
- Pallav Kosuri
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.,Department of Physics, Harvard University, Cambridge, MA, USA
| | - Benjamin D Altheimer
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.,Department of Physics, Harvard University, Cambridge, MA, USA.,Graduate Program in Biophysics, Harvard University, Cambridge, MA, USA
| | - Mingjie Dai
- Graduate Program in Biophysics, Harvard University, Cambridge, MA, USA.,Wyss Institute for Biologically Inspired Engineering, Harvard Medical School, Boston, MA, USA.,Department of Systems Biology, Harvard Medical School, Boston, MA, USA
| | - Peng Yin
- Wyss Institute for Biologically Inspired Engineering, Harvard Medical School, Boston, MA, USA.,Department of Systems Biology, Harvard Medical School, Boston, MA, USA
| | - Xiaowei Zhuang
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA. .,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA. .,Department of Physics, Harvard University, Cambridge, MA, USA.
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47
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Nomidis SK, Skoruppa E, Carlon E, Marko JF. Twist-bend coupling and the statistical mechanics of the twistable wormlike-chain model of DNA: Perturbation theory and beyond. Phys Rev E 2019; 99:032414. [PMID: 30999490 DOI: 10.1103/physreve.99.032414] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Indexed: 12/12/2022]
Abstract
The simplest model of DNA mechanics describes the double helix as a continuous rod with twist and bend elasticity. Recent work has discussed the relevance of a little-studied coupling G between twisting and bending, known to arise from the groove asymmetry of the DNA double helix. Here the effect of G on the statistical mechanics of long DNA molecules subject to applied forces and torques is investigated. We present a perturbative calculation of the effective torsional stiffness C_{eff} for small twist-bend coupling. We find that the "bare" G is "screened" by thermal fluctuations, in the sense that the low-force, long-molecule effective free energy is that of a model with G=0 but with long-wavelength bending and twisting rigidities that are shifted by G-dependent amounts. Using results for torsional and bending rigidities for freely fluctuating DNA, we show how our perturbative results can be extended to a nonperturbative regime. These results are in excellent agreement with numerical calculations for Monte Carlo "triad" and molecular dynamics "oxDNA" models, characterized by different degrees of coarse graining, validating the perturbative and nonperturbative analyses. While our theory is in generally good quantitative agreement with experiment, the predicted torsional stiffness does systematically deviate from experimental data, suggesting that there are as-yet-uncharacterized aspects of DNA twisting-stretching mechanics relevant to low-force, long-molecule mechanical response, which are not captured by widely used coarse-grained models.
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Affiliation(s)
- Stefanos K Nomidis
- KU Leuven, Institute for Theoretical Physics, Celestijnenlaan 200D, 3001 Leuven, Belgium.,Flemish Institute for Technological Research (VITO), Boeretang 200, B-2400 Mol, Belgium
| | - Enrico Skoruppa
- KU Leuven, Institute for Theoretical Physics, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - Enrico Carlon
- KU Leuven, Institute for Theoretical Physics, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - John F Marko
- Department of Physics and Astronomy, and Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA
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48
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Caraglio M, Skoruppa E, Carlon E. Overtwisting induces polygonal shapes in bent DNA. J Chem Phys 2019; 150:135101. [PMID: 30954045 DOI: 10.1063/1.5084950] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
By combining analytical results and simulations of various coarse-grained models, we investigate the minimal energy shape of DNA minicircles which are torsionally constrained by an imposed over or undertwist. We show that twist-bend coupling, a cross interaction term discussed in the recent DNA literature, induces minimal energy shapes with a periodic alternation of parts with high and low curvature resembling rounded polygons. We briefly discuss the possible experimental relevance of these findings. We finally show that the twist and bending energies of minicircles are governed by renormalized stiffness constants, rather than the bare ones. This has important consequences for the analysis of experiments involving circular DNA meant to determine DNA elastic constants.
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Affiliation(s)
- Michele Caraglio
- Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - Enrico Skoruppa
- Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - Enrico Carlon
- Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
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Brouns T, De Keersmaecker H, Konrad SF, Kodera N, Ando T, Lipfert J, De Feyter S, Vanderlinden W. Free Energy Landscape and Dynamics of Supercoiled DNA by High-Speed Atomic Force Microscopy. ACS NANO 2018; 12:11907-11916. [PMID: 30346700 DOI: 10.1021/acsnano.8b06994] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
DNA supercoiling fundamentally constrains and regulates the storage and use of genetic information. While the equilibrium properties of supercoiled DNA are relatively well understood, the dynamics of supercoils are much harder to probe. Here we use atomic force microscopy (AFM) imaging to demonstrate that positively supercoiled DNA plasmids, in contrast to their negatively supercoiled counterparts, preserve their plectonemic geometry upon adsorption under conditions that allow for dynamics and equilibration on the surface. Our results are in quantitative agreement with a physical polymer model for supercoiled plasmids that takes into account the known mechanical properties and torque-induced melting of DNA. We directly probe supercoil dynamics using high-speed AFM imaging with subsecond time and ∼nanometer spatial resolution. From our recordings we quantify self-diffusion, branch point flexibility, and slithering dynamics and demonstrate that reconfiguration of molecular extensions is predominantly governed by the bending flexibility of plectoneme arms. We expect that our methodology can be an asset to probe protein-DNA interactions and topochemical reactions on physiological relevant DNA length and supercoiling scales by high-resolution AFM imaging.
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Affiliation(s)
- Tine Brouns
- KU Leuven, Division of Molecular Imaging and Photonics , Celestijnenlaan 200F , 3001 Leuven , Belgium
| | - Herlinde De Keersmaecker
- KU Leuven, Division of Molecular Imaging and Photonics , Celestijnenlaan 200F , 3001 Leuven , Belgium
| | - Sebastian F Konrad
- Department of Physics , Nanosystems Initiative Munich, and Center for NanoScience , LMU Munich, Amalienstrasse 54 , 80799 Munich , Germany
| | - Noriyuki Kodera
- Nano-Life Science Institute (WPI-NanoLSI) , Kanazawa University , Kakuma-machi , Kanazawa , 920-1192 , Japan
| | - Toshio Ando
- Nano-Life Science Institute (WPI-NanoLSI) , Kanazawa University , Kakuma-machi , Kanazawa , 920-1192 , Japan
| | - Jan Lipfert
- Department of Physics , Nanosystems Initiative Munich, and Center for NanoScience , LMU Munich, Amalienstrasse 54 , 80799 Munich , Germany
| | - Steven De Feyter
- KU Leuven, Division of Molecular Imaging and Photonics , Celestijnenlaan 200F , 3001 Leuven , Belgium
| | - Willem Vanderlinden
- KU Leuven, Division of Molecular Imaging and Photonics , Celestijnenlaan 200F , 3001 Leuven , Belgium
- Department of Physics , Nanosystems Initiative Munich, and Center for NanoScience , LMU Munich, Amalienstrasse 54 , 80799 Munich , Germany
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50
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Rezaei N, Lyons A, Forde NR. Environmentally Controlled Curvature of Single Collagen Proteins. Biophys J 2018; 115:1457-1469. [PMID: 30269884 PMCID: PMC6260212 DOI: 10.1016/j.bpj.2018.09.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 08/02/2018] [Accepted: 09/04/2018] [Indexed: 12/01/2022] Open
Abstract
The predominant structural protein in vertebrates is collagen, which plays a key role in extracellular matrix and connective tissue mechanics. Despite its prevalence and physical importance in biology, the mechanical properties of molecular collagen are far from established. The flexibility of its triple helix is unresolved, with descriptions from different experimental techniques ranging from flexible to semirigid. Furthermore, it is unknown how collagen type (homo- versus heterotrimeric) and source (tissue derived versus recombinant) influence flexibility. Using SmarTrace, a chain-tracing algorithm we devised, we performed statistical analysis of collagen conformations collected with atomic force microscopy to determine the protein's mechanical properties. Our results show that types I, II, and III collagens-the key fibrillar varieties-exhibit similar molecular flexibilities. However, collagen conformations are strongly modulated by salt, transitioning from compact to extended as KCl concentration increases in both neutral and acidic pH. Although analysis with a standard worm-like chain model suggests that the persistence length of collagen can attain a wide range of values within the literature range, closer inspection reveals that this modulation of collagen's conformational behavior is not due to changes in flexibility but rather arises from the induction of curvature (either intrinsic or induced by interactions with the mica surface). By modifying standard polymer theory to include innate curvature, we show that collagen behaves as an equilibrated curved worm-like chain in two dimensions. Analysis within the curved worm-like chain model shows that collagen's curvature depends strongly on pH and salt, whereas its persistence length does not. Thus, we find that triple-helical collagen is well described as semiflexible irrespective of source, type, pH, and salt environment. These results demonstrate that collagen is more flexible than its conventional description as a rigid rod, which may have implications for its cellular processing and secretion.
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Affiliation(s)
- Nagmeh Rezaei
- Department of Physics, Simon Fraser University, Burnaby, Canada
| | - Aaron Lyons
- Department of Physics, Simon Fraser University, Burnaby, Canada
| | - Nancy R Forde
- Department of Physics, Simon Fraser University, Burnaby, Canada.
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