1
|
Laeremans W, Segers M, Voorspoels A, Carlon E, Hooyberghs J. Insights into elastic properties of coarse-grained DNA models: q-stiffness of cgDNA vs cgDNA. J Chem Phys 2024; 160:144105. [PMID: 38591677 DOI: 10.1063/5.0197053] [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: 01/11/2024] [Accepted: 03/19/2024] [Indexed: 04/10/2024] Open
Abstract
Coarse-grained models have emerged as valuable tools to simulate long DNA molecules while maintaining computational efficiency. These models aim at preserving interactions among coarse-grained variables in a manner that mirrors the underlying atomistic description. We explore here a method for testing coarse-grained vs all-atom models using stiffness matrices in Fourier space (q-stiffnesses), which are particularly suited to probe DNA elasticity at different length scales. We focus on a class of coarse-grained rigid base DNA models known as cgDNA and its most recent version, cgDNA+. Our analysis shows that while cgDNA+ closely follows the q-stiffnesses of the all-atom model, the original cgDNA shows some deviations for twist and bending variables, which are rather strong in the q → 0 (long length scale) limit. The consequence is that while both cgDNA and cgDNA+ give a suitable description of local elastic behavior, the former misses some effects that manifest themselves at longer length scales. In particular, cgDNA performs poorly on twist stiffness, with a value much lower than expected for long DNA molecules. Conversely, the all-atom and cgDNA+ twist are strongly length scale dependent: DNA is torsionally soft at a few base pair distances but becomes more rigid at distances of a few dozen base pairs. Our analysis shows that the bending persistence length in all-atom and cgDNA+ is somewhat overestimated.
Collapse
Affiliation(s)
- Wout Laeremans
- Soft Matter and Biological Physics, Department of Applied Physics, and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, Netherlands
- Soft Matter and Biophysics Unit, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
- UHasselt, Faculty of Sciences, Data Science Institute, Theory Lab, Agoralaan, 3590 Diepenbeek, Belgium
| | - 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
| | - Enrico Carlon
- Soft Matter and Biophysics Unit, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - Jef Hooyberghs
- UHasselt, Faculty of Sciences, Data Science Institute, Theory Lab, Agoralaan, 3590 Diepenbeek, Belgium
| |
Collapse
|
2
|
Luengo-Márquez J, Zalvide-Pombo J, Pérez R, Assenza S. Force-dependent elasticity of nucleic acids. NANOSCALE 2023; 15:6738-6744. [PMID: 36942727 DOI: 10.1039/d2nr06324g] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The functioning of double-stranded (ds) nucleic acids (NAs) in cellular processes is strongly mediated by their elastic response. These processes involve proteins that interact with dsDNA or dsRNA and distort their structures. The perturbation of the elasticity of NAs arising from these deformations is not properly considered by most theoretical frameworks. In this work, we introduce a novel method to assess the impact of mechanical stress on the elastic response of dsDNA and dsRNA through the analysis of the fluctuations of the double helix. Application of this approach to atomistic simulations reveals qualitative differences in the force dependence of the mechanical properties of dsDNA with respect to those of dsRNA, which we relate to structural features of these molecules by means of physically-sound minimalistic models.
Collapse
Affiliation(s)
- Juan Luengo-Márquez
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
- Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Juan Zalvide-Pombo
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
| | - Rubén Pérez
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid, Spain.
| | - Salvatore Assenza
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid, Spain.
- Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| |
Collapse
|
3
|
Rissanou AN, Karatasos K. Effects of the structure of lipid-based agents in their complexation with a single stranded mRNA fragment: a computational study. SOFT MATTER 2022; 18:6229-6245. [PMID: 35904818 DOI: 10.1039/d2sm00403h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In this work we employed fully atomistic molecular dynamics simulations, aiming towards a better understanding of the mechanisms associated with the formation and the stability of lipid-based RNA nanoassemblies, in an aqueous environment. We examined two groups of lipid-based complexation agents, differing in the degree of hydrophobicity and in the overall charge. The first group was comprised of cationic ionizable agents while the second included electrically neutral amphoteric phosphatidylcholine lipids. It was found that the overall charge of the complexation agents played the most decisive role in the energetics of the lipid/RNA association, while their degree of hydrophobicity affected their self-assembly and their complexation kinetics. The latter also affected the structural stability of the formed complexes since the water entrapped within the clusters of the less hydrophobic agents appeared to reduce the coherence of the lipid-RNA nanoassemblies. The combined effects of the aforementioned attributes dictated also the RNA conformation after complexation. The results from the present study provide thus new insight towards controlling the morphology, the energetic stability and the structural integrity of the formed complexes.
Collapse
Affiliation(s)
- Anastassia N Rissanou
- Department of Chemical Engineering, University of Thessaloniki, P.O. BOX 420, 54124 Thessaloniki, Greece.
- Department of Mathematics and Applied Mathematics, University of Crete, GR-71409, Heraklion, Crete, Greece.
| | - Kostas Karatasos
- Department of Chemical Engineering, University of Thessaloniki, P.O. BOX 420, 54124 Thessaloniki, Greece.
| |
Collapse
|
4
|
Al Qanobi A, Marenduzzo D, Ali I. Simulations of DNA denaturation dynamics under constrained conditions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:295101. [PMID: 35512678 DOI: 10.1088/1361-648x/ac6d39] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 05/05/2022] [Indexed: 06/14/2023]
Abstract
We study the dynamics of double-stranded DNA (dsDNA) denaturation using Brownian dynamics simulations. We use a coarse-grained single nucleotide model for dsDNA which considers the helix structure. We compare the melting dynamics for free DNA of length 300 base pairs with that of a DNA of the same length but fixed from one end-mimicking DNA tethered to a substrate. We find that free DNA melts at faster rate because the entropic gain associated with denaturation is larger. Additionally, we insert the DNA in nanochannels of different widths to study the influence of the confinement on the melting dynamics. Our results suggest that there is no significant difference in the critical temperature or rate of melting when the channel width⩾Rg/2, whereRgis the radius of gyration of DNA. Instead, at channel width ofRg/4 we only see partial denaturation at the free DNA melting temperature. Surprisingly, this trend is reversed at higher temperature, and we find that at 110 °C tight confinement results in faster melting. This is due to the fact that confinement promotes segregation of the single-stranded segment, thereby acting as an effective entropic force aiding denaturation.
Collapse
Affiliation(s)
- A Al Qanobi
- Department of Physics, College of Science, Sultan Qaboos University, PO Box 36, Al-Khod 123, Oman
| | - D Marenduzzo
- SUPA, School of Physics and Astronomy, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom
| | - I Ali
- Department of Physics, College of Science, Sultan Qaboos University, PO Box 36, Al-Khod 123, Oman
| |
Collapse
|
5
|
Chiang M, Brackley CA, Marenduzzo D, Gilbert N. Predicting genome organisation and function with mechanistic modelling. Trends Genet 2021; 38:364-378. [PMID: 34857425 DOI: 10.1016/j.tig.2021.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/11/2021] [Accepted: 11/01/2021] [Indexed: 12/14/2022]
Abstract
Fitting-free mechanistic models based on polymer simulations predict chromatin folding in 3D by focussing on the underlying biophysical mechanisms. This class of models has been increasingly used in conjunction with experiments to study the spatial organisation of eukaryotic chromosomes. Feedback from experiments to models leads to successive model refinement and has previously led to the discovery of new principles for genome organisation. Here, we review the basis of mechanistic polymer simulations, explain some of the more recent approaches and the contexts in which they have been useful to explain chromosome biology, and speculate on how they might be used in the future.
Collapse
Affiliation(s)
- Michael Chiang
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, UK
| | - Chris A Brackley
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, UK
| | - Davide Marenduzzo
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, UK
| | - Nick Gilbert
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Crewe Road South, Edinburgh, EH4 2XU, UK.
| |
Collapse
|
6
|
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
| |
Collapse
|
7
|
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.
Collapse
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
| |
Collapse
|
8
|
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.
Collapse
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
Rissanou AN, Ouranidis A, Karatasos K. Complexation of single stranded RNA with an ionizable lipid: an all-atom molecular dynamics simulation study. SOFT MATTER 2020; 16:6993-7005. [PMID: 32667026 DOI: 10.1039/d0sm00736f] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Complexation of a lipid-based ionizable cationic molecule (referred to as DML: see main text) with RNA in an aqueous medium was examined in detail by means of fully atomistic molecular dynamics simulations. The different stages of the DML-RNA association process were explored, while the structural characteristics of the final complex were described. The self-assembly process of the DML molecules was examined in the absence and in the presence of nucleotide sequences of different lengths. The formed DML clusters were described in detail in terms of their size and composition and were found to share common features in all the examined systems. Different timescales related to their self-assembly and their association with RNA were identified. It was found that beyond a time period of a few tens of ns, a conformationally stable DML-RNA complex was formed, characterized by DML clusters covering the entire contour of RNA. In a system with a 642-nucleotide sequence, the average size of the complex in the longest dimension was found to be close to 40 nm. The DML clusters were characterized by a rather low surface charge, while a propensity for the formation of larger size clusters close to RNA was noted. Apart from hydrophobic and electrostatic interactions, hydrogen bonding was found to play a key-role in the DML-DML and in the DML-RNA association. The information obtained regarding the structural features of the final complex, the timescales and the driving forces associated with the complexation and the self-assembly processes provide new insight towards a rational design of optimized lipid-based ionizable cationic gene delivery vectors.
Collapse
Affiliation(s)
- Anastassia N Rissanou
- Department of Chemical Engineering, University of Thessaloniki, P.O. BOX 420, 54124 Thessaloniki, Greece.
| | | | | |
Collapse
|
11
|
Brackey CA, Marenduzzo D, Gilbert N. Mechanistic modeling of chromatin folding to understand function. Nat Methods 2020; 17:767-775. [PMID: 32514111 DOI: 10.1038/s41592-020-0852-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Accepted: 04/29/2020] [Indexed: 01/06/2023]
Abstract
Experimental approaches have been applied to address questions in understanding three-dimensional chromatin organization and function. As datasets increase in size and complexity, it becomes a challenge to reach a mechanistic interpretation of experimental results. Polymer simulations and mechanistic modeling have been applied to explain experimental observations and their links to different aspects of genome function. Here we provide a guide for biologists, explaining different simulation approaches and the contexts in which they have been used.
Collapse
Affiliation(s)
- Chris A Brackey
- SUPA School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
| | - Davide Marenduzzo
- SUPA School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK.
| | - Nick Gilbert
- MRC Human Genetics Unit, Institute of Genetics & Molecular Medicine, University of Edinburgh, Edinburgh, UK.
| |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
Xing Z, Ness C, Frenkel D, Eiser E. Structural and Linear Elastic Properties of DNA Hydrogels by Coarse-Grained Simulation. Macromolecules 2019. [DOI: 10.1021/acs.macromol.8b01948] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Zhongyang Xing
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Christopher Ness
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, United Kingdom
| | - Daan Frenkel
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Erika Eiser
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| |
Collapse
|
14
|
Chakraborty D, Hori N, Thirumalai D. Sequence-Dependent Three Interaction Site Model for Single- and Double-Stranded DNA. J Chem Theory Comput 2018; 14:3763-3779. [PMID: 29870236 PMCID: PMC6423546 DOI: 10.1021/acs.jctc.8b00091] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
We develop a robust coarse-grained model for single- and double-stranded DNA by representing each nucleotide by three interaction sites (TIS) located at the centers of mass of sugar, phosphate, and base. The resulting TIS model includes base-stacking, hydrogen bond, and electrostatic interactions as well as bond-stretching and bond angle potentials that account for the polymeric nature of DNA. The choices of force constants for stretching and the bending potentials were guided by a Boltzmann inversion procedure using a large representative set of DNA structures extracted from the Protein Data Bank. Some of the parameters in the stacking interactions were calculated using a learning procedure, which ensured that the experimentally measured melting temperatures of dimers are faithfully reproduced. Without any further adjustments, the calculations based on the TIS model reproduce the experimentally measured salt and sequence-dependence of the size of single-stranded DNA (ssDNA), as well as the persistence lengths of poly(dA) and poly(dT) chains. Interestingly, upon application of mechanical force, the extension of poly(dA) exhibits a plateau, which we trace to the formation of stacked helical domains. In contrast, the force-extension curve (FEC) of poly(dT) is entropic in origin and could be described by a standard polymer model. We also show that the persistence length of double-stranded DNA, formed from two complementary ssDNAs, is consistent with the prediction based on the worm-like chain. The persistence length, which decreases with increasing salt concentration, is in accord with the Odijk-Skolnick-Fixman theory intended for stiff polyelectrolyte chains near the rod limit. Our model predicts the melting temperatures of DNA hairpins with excellent accuracy, and we are able to recover the experimentally known sequence-specific trends. The range of applications, which did not require adjusting any parameter after the initial construction based solely on PDB structures and melting profiles of dimers, attests to the transferability and robustness of the TIS model for ssDNA and dsDNA.
Collapse
Affiliation(s)
- Debayan Chakraborty
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Naoto Hori
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - D. Thirumalai
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| |
Collapse
|
15
|
Henrich O, Gutiérrez Fosado YA, Curk T, Ouldridge TE. Coarse-grained simulation of DNA using LAMMPS : An implementation of the oxDNA model and its applications. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2018; 41:57. [PMID: 29748779 DOI: 10.1140/epje/i2018-11669-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 04/19/2018] [Indexed: 05/25/2023]
Abstract
During the last decade coarse-grained nucleotide models have emerged that allow us to study DNA and RNA on unprecedented time and length scales. Among them is oxDNA, a coarse-grained, sequence-specific model that captures the hybridisation transition of DNA and many structural properties of single- and double-stranded DNA. oxDNA was previously only available as standalone software, but has now been implemented into the popular LAMMPS molecular dynamics code. This article describes the new implementation and analyses its parallel performance. Practical applications are presented that focus on single-stranded DNA, an area of research which has been so far under-investigated. The LAMMPS implementation of oxDNA lowers the entry barrier for using the oxDNA model significantly, facilitates future code development and interfacing with existing LAMMPS functionality as well as other coarse-grained and atomistic DNA models.
Collapse
Affiliation(s)
- Oliver Henrich
- Department of Physics, SUPA, University of Strathclyde, G4 0NG, Glasgow, Scotland, UK.
| | | | - Tine Curk
- CAS Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- Department of Chemistry, University of Cambridge, CB2 1EW, Cambridge, UK
| | - Thomas E Ouldridge
- Department of Bioengineering, Imperial College London, SW7 2AZ, London, UK
- Centre of Synthetic Biology, Imperial College London, SW7 2AZ, London, UK
| |
Collapse
|
16
|
Fosado YAG, Michieletto D, Marenduzzo D. Dynamical Scaling and Phase Coexistence in Topologically Constrained DNA Melting. PHYSICAL REVIEW LETTERS 2017; 119:118002. [PMID: 28949232 DOI: 10.1103/physrevlett.119.118002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Indexed: 06/07/2023]
Abstract
There is a long-standing experimental observation that the melting of topologically constrained DNA, such as circular closed plasmids, is less abrupt than that of linear molecules. This finding points to an important role of topology in the physics of DNA denaturation, which is, however, poorly understood. Here, we shed light on this issue by combining large-scale Brownian dynamics simulations with an analytically solvable phenomenological Landau mean field theory. We find that the competition between melting and supercoiling leads to phase coexistence of denatured and intact phases at the single-molecule level. This coexistence occurs in a wide temperature range, thereby accounting for the broadening of the transition. Finally, our simulations show an intriguing topology-dependent scaling law governing the growth of denaturation bubbles in supercoiled plasmids, which can be understood within the proposed mean field theory.
Collapse
Affiliation(s)
- Y A G Fosado
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom
| | - D Michieletto
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom
| | - D Marenduzzo
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom
| |
Collapse
|