1
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Kodikara S, Gyawali P, Gleeson JT, Jákli A, Sprunt S, Balci H. Impact of Divalent Cations on In-Layer Positional Order of DNA-Based Liquid Crystals: Implications for DNA Condensation. Biomacromolecules 2024; 25:1009-1017. [PMID: 38166360 PMCID: PMC10866144 DOI: 10.1021/acs.biomac.3c01086] [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: 10/10/2023] [Revised: 12/12/2023] [Accepted: 12/12/2023] [Indexed: 01/04/2024]
Abstract
The layered liquid crystalline phases formed by DNA molecules, which include rigid and flexible segments ("gapped DNA"), enable the study of both end-to-end stacking and side-to-side (helix-to-helix) lateral interactions, forming a model system to study such interactions at physiologically relevant DNA and ion concentrations. The observed layer structure exhibits long-range interlayer and in-layer positional correlations. In particular, the in-layer order has implications for DNA condensation, as it reflects whether these normally repulsive interactions become attractive under certain ionic conditions. Using synchrotron small-angle X-ray scattering measurements, we investigate the impact of divalent Mg2+ cations (in addition to a constant 150 mM Na+) on the stability of the inter- and in-layer DNA ordering as a function of temperature between 5 and 65 °C. DNA constructs with different terminal base pairings were created to mediate the strength of the attractive end-to-end stacking interactions between the blunt ends of the gapped DNA constructs. We demonstrate that the stabilities at a fixed DNA concentration of both interlayer and in-layer order are significantly enhanced even at a few mM Mg2+ concentration. The stabilities are even higher at 30 mM Mg2+; however, a marked decrease is observed at 100 mM Mg2+, suggesting a change in the nature of side-by-side interactions within this Mg2+ concentration range. We discuss the implications of these results in terms of counterion-mediated DNA-DNA attraction and DNA condensation.
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Affiliation(s)
- Sineth
G. Kodikara
- Department
of Physics, Kent State University, Kent, Ohio 44242, United States
| | - Prabesh Gyawali
- Department
of Physics, Kent State University, Kent, Ohio 44242, United States
| | - James T. Gleeson
- Department
of Physics, Kent State University, Kent, Ohio 44242, United States
| | - Antal Jákli
- Department
of Physics, Kent State University, Kent, Ohio 44242, United States
- Advanced
Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242, United States
| | - Samuel Sprunt
- Department
of Physics, Kent State University, Kent, Ohio 44242, United States
- Advanced
Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242, United States
| | - Hamza Balci
- Department
of Physics, Kent State University, Kent, Ohio 44242, United States
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2
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Coste A, Slejko E, Zavadlav J, Praprotnik M. Developing an Implicit Solvation Machine Learning Model for Molecular Simulations of Ionic Media. J Chem Theory Comput 2024; 20:411-420. [PMID: 38118122 PMCID: PMC10782447 DOI: 10.1021/acs.jctc.3c00984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 12/04/2023] [Accepted: 12/04/2023] [Indexed: 12/22/2023]
Abstract
Molecular dynamics (MD) simulations of biophysical systems require accurate modeling of their native environment, i.e., aqueous ionic solution, as it critically impacts the structure and function of biomolecules. On the other hand, the models should be computationally efficient to enable simulations of large spatiotemporal scales. Here, we present the deep implicit solvation model for sodium chloride solutions that satisfies both requirements. Owing to the use of the neural network potential, the model can capture the many-body potential of mean force, while the implicit water treatment renders the model inexpensive. We demonstrate our approach first for pure ionic solutions with concentrations ranging from physiological to 2 M. We then extend the model to capture the effective ion interactions in the vicinity and far away from a DNA molecule. In both cases, the structural properties are in good agreement with all-atom MD, showcasing a general methodology for the efficient and accurate modeling of ionic media.
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Affiliation(s)
- Amaury Coste
- Laboratory
for Molecular Modeling, National Institute of Chemistry, Ljubljana SI-1001, Slovenia
| | - Ema Slejko
- Laboratory
for Molecular Modeling, National Institute of Chemistry, Ljubljana SI-1001, Slovenia
- Department
of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana SI-1000, Slovenia
| | - Julija Zavadlav
- Professorship
of Multiscale Modeling of Fluid Materials, TUM School of Engineering
and Design, Technical University of Munich, Garching Near Munich DE-85748, Germany
| | - Matej Praprotnik
- Laboratory
for Molecular Modeling, National Institute of Chemistry, Ljubljana SI-1001, Slovenia
- Department
of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana SI-1000, Slovenia
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3
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Papadopoulou E, Zavadlav J, Podgornik R, Praprotnik M, Koumoutsakos P. Tuning the Dielectric Response of Water in Nanoconfinement through Surface Wettability. ACS NANO 2021; 15:20311-20318. [PMID: 34813279 DOI: 10.1021/acsnano.1c08512] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The tunable polarity of water can be exploited in emerging technologies including catalysis, gas storage, and green chemistry. Recent experimental and theoretical studies have shown that water can be rendered into an effectively apolar solvent under nanoconfinement. We furthermore demonstrate, through molecular simulations, that the static dielectric constant of water can be modified by changing the wettability of the confining material. We find the out-of-plane dielectric response to be highly sensitive to the level of confinement and can be reduced up to 40× , in accordance with experimental data. By altering the surface wettability from superhydrophilic to superhydrophobic, we observe a 36% increase for the out-of-plane and a 31% decrease for the in-plane dielectric constants. Our findings demonstrate the feasibility of tunable water polarity, a phenomenon with great potential for scientific and technological impact.
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Affiliation(s)
- Ermioni Papadopoulou
- Computational Science and Engineering Laboratory, ETH-Zurich, Clausiusstrasse 33, CH-8092 Zurich, Switzerland
| | - Julija Zavadlav
- Professorship of Multiscale Modeling of Fluid Materials, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstrasse 15, DE-85748 Garching near Munich, Germany
| | - Rudolf Podgornik
- School of Physical Sciences and Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana, Slovenia
- CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Wenzhou Institute of the University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325000, China
| | - Matej Praprotnik
- Laboratory for Molecular Modeling, National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia
- Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana, Slovenia
| | - Petros Koumoutsakos
- Computational Science and Engineering Laboratory, ETH-Zurich, Clausiusstrasse 33, CH-8092 Zurich, Switzerland
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
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4
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Cortes-Huerto R, Praprotnik M, Kremer K, Delle Site L. From adaptive resolution to molecular dynamics of open systems. THE EUROPEAN PHYSICAL JOURNAL. B 2021; 94:189. [PMID: 34720711 PMCID: PMC8547219 DOI: 10.1140/epjb/s10051-021-00193-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 08/31/2021] [Indexed: 05/14/2023]
Abstract
ABSTRACT We provide an overview of the Adaptive Resolution Simulation method (AdResS) based on discussing its basic principles and presenting its current numerical and theoretical developments. Examples of applications to systems of interest to soft matter, chemical physics, and condensed matter illustrate the method's advantages and limitations in its practical use and thus settle the challenge for further future numerical and theoretical developments.
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Affiliation(s)
| | - Matej Praprotnik
- Laboratory for Molecular Modeling, National Institute of Chemistry, Ljubljana, Slovenia and Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia
| | - Kurt Kremer
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Luigi Delle Site
- Department of Mathematics and Computer Science, Institute for Mathematics, Freie Universität Berlin, Berlin, Germany
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5
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Liu X, Korotkin I, Rao Z, Karabasov S. A Thermostat‐Consistent Fully Coupled Molecular Dynamics—Generalized Fluctuating Hydrodynamics Model. ADVANCED THEORY AND SIMULATIONS 2020. [DOI: 10.1002/adts.202000209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Xinjian Liu
- School of Electrical and Power Engineering China University of Mining and Technology Xuzhou 221116 China
- The School of Engineering and Materials Science Queen Mary University of London Mile End Road London E1 4NS UK
| | - Ivan Korotkin
- Mathematical Sciences University of Southampton University Rd. Southampton SO17 1BJ UK
| | - Zhonghao Rao
- School of Electrical and Power Engineering China University of Mining and Technology Xuzhou 221116 China
| | - Sergey Karabasov
- The School of Engineering and Materials Science Queen Mary University of London Mile End Road London E1 4NS UK
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6
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Meng W, Timsina R, Bull A, Andresen K, Qiu X. Additive Modulation of DNA-DNA Interactions by Interstitial Ions. Biophys J 2020; 118:3019-3025. [PMID: 32470322 DOI: 10.1016/j.bpj.2020.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 04/04/2020] [Accepted: 04/28/2020] [Indexed: 11/26/2022] Open
Abstract
Quantitative understanding of biomolecular electrostatics, particularly involving multivalent ions and highly charged surfaces, remains lacking. Ion-modulated interactions between nucleic acids provide a model system in which electrostatics plays a dominant role. Using ordered DNA arrays neutralized by spherical cobalt3+ hexammine and Mg2+ ions, we investigate how the interstitial ions modulate DNA-DNA interactions. Using methods of ion counting, osmotic stress, and x-ray diffraction, we systematically determine thermodynamic quantities, including ion chemical potentials, ion partition, DNA osmotic pressure and force, and DNA-DNA spacing. Analyses of the multidimensional data provide quantitative insights into their interdependencies. The key finding of this study is that DNA-DNA forces are observed to linearly depend on the partition of interstitial ions, suggesting the dominant role of ion-DNA coupling. Further implications are discussed in light of physical theories of electrostatic interactions and like-charge attraction.
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Affiliation(s)
- Wei Meng
- Key Lab of Biofabrication of Anhui Higher Education Institution Centre for Advanced Biofabrication, Hefei University, Hefei, Anhui, China; Department of Physics, George Washington University, Washington, District of Columbia
| | - Raju Timsina
- Department of Physics, George Washington University, Washington, District of Columbia
| | - Abby Bull
- Department of Physics, Gettysburg College, Gettysburg, Pennsylvania
| | - Kurt Andresen
- Department of Physics, Gettysburg College, Gettysburg, Pennsylvania.
| | - Xiangyun Qiu
- Department of Physics, George Washington University, Washington, District of Columbia.
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7
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Delle Site L, Praprotnik M, Bell JB, Klein R. Particle–Continuum Coupling and its Scaling Regimes: Theory and Applications. ADVANCED THEORY AND SIMULATIONS 2020. [DOI: 10.1002/adts.201900232] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Luigi Delle Site
- Freie Universität Berlin Institute of Mathematics Arnimallee 6, 14195 Berlin Germany
| | - Matej Praprotnik
- Laboratory for Molecular Modeling National Institute of Chemistry SI‐1001 Ljubljana, Slovenia & Department of Physics Faculty of Mathematics and Physics University of Ljubljana SI‐1000 Ljubljana Slovenia
| | - John B. Bell
- Lawrence Berkeley National Lab 1 Cyclotron Rd. Berkeley CA 94720 USA
| | - Rupert Klein
- Freie Universität Berlin Institute of Mathematics Arnimallee 6, 14195 Berlin Germany
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8
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Naskar S, Saurabh S, Jang YH, Lansac Y, Maiti PK. Liquid crystal ordering of nucleic acids. SOFT MATTER 2020; 16:634-641. [PMID: 31840704 DOI: 10.1039/c9sm01816f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Several analytical calculations and computer simulations propose that cylindrical monodispersive rods having an aspect ratio (ratio of length to diameter) greater than 4 can exhibit liquid crystal (LC) ordering. But, recent experiments demonstrated the signature of LC ordering in systems of 4- to 20-base pair (bp) long nucleic acids (NAs) that do not satisfy the shape anisotropy criterion. Mechanisms of end-to-end adhesion and stacking have been proposed to explain this phenomenon. In this study, using all-atom molecular dynamics (MD) simulation, we explicitly verify the end-to-end stacking of double-stranded RNA (dsRNA) and demonstrate the LC ordering at the microscopic level. Using umbrella sampling (US) calculation, we quantify the potential of mean force (PMF) between two dsRNAs for various reaction coordinates (RCs) and compare our results with previously reported PMFs for double-stranded DNA (dsDNA). The PMF profiles demonstrate the anisotropic nature of inter-NA interaction. We find that, like dsDNA, dsRNA also prefers to stack on top of each other while repelling sideways, leading to the formation of supra-molecular-columns that undergo LC ordering at high NA volume fraction (φ). We also demonstrate and quantify the nematic ordering of the RNAs using several hundred nanosecond-long MD simulations that remain almost invariant for different initial configurations and under different external physiological conditions.
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Affiliation(s)
- Supriyo Naskar
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India.
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9
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Chen X, Chen EQ, Yang S. Multivalent counterions induced attraction between DNA polyelectrolytes. RSC Adv 2020; 10:1890-1900. [PMID: 35494593 PMCID: PMC9048762 DOI: 10.1039/c9ra09694a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 12/30/2019] [Indexed: 12/26/2022] Open
Abstract
In this paper we study the electrostatic attraction between two parallel rodlike DNA polyelectrolytes induced by neutralizing multivalent counterions at the zero temperature limit. The counterions crystallize on the charged surfaces of DNA so that we can handle the system by using the Wigner crystal lattice model. We derived the 3D ground state configuration of counterions with minimized energy by use of the gradient descent method, and calculated the interaction between two DNA cylinders with divalent or trivalent counterions when they approach. The results show that the complex ground state configuration of counterions plays a key role in determining the caused attraction. The counterions form three-dimensional Wigner crystals on each cylinder at large separation. When the cylinders are brought together, some counterion lines will move towards the inner region and lead to strong attraction. The calculated interaction from our model is in good agreement with the simulation result, however, the single particle approximation considerably overestimates the attraction. Counterions in the ground state partially condense in the intervening region of two approaching DNA cylinders and result in attraction.![]()
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Affiliation(s)
- Xu Chen
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Mater Science and Engineering, College of Chemistry and Molecular Engineering, Peking University Beijing 100871 China
| | - Er-Qiang Chen
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Mater Science and Engineering, College of Chemistry and Molecular Engineering, Peking University Beijing 100871 China
| | - Shuang Yang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Mater Science and Engineering, College of Chemistry and Molecular Engineering, Peking University Beijing 100871 China
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10
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Dos Santos MAF, Habitzreuter MA, Schwade MH, Borrasca R, Antonacci M, Gonzatti GK, Netz PA, Barbosa MC. Dynamical aspects of supercooled TIP3P-water in the grooves of DNA. J Chem Phys 2019; 150:235101. [PMID: 31228916 DOI: 10.1063/1.5100601] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
We investigate by molecular dynamics simulations the mobility of the water located at the DNA minor and major grooves. We employ the TIP3P water model, and our system is analyzed for a range of temperatures 190-300 K. For high temperatures, the water at the grooves shows an Arrhenius behavior similar to that observed in the bulk water. At lower temperatures, a departure from the bulk behavior is observed. This slowing down in the dynamics is compared with the dynamics of the hydrogen of the DNA at the grooves and with the autocorrelation functions of the water hydrogen bonds. Our results indicate that the hydrogen bonds of the water at the minor grooves are highly correlated, which suggests that this is the mechanism for the slow dynamics at this high confinement.
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Affiliation(s)
- M A F Dos Santos
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS, Brazil
| | - M A Habitzreuter
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS, Brazil
| | - M H Schwade
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS, Brazil
| | - R Borrasca
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS, Brazil
| | - M Antonacci
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS, Brazil
| | - G K Gonzatti
- Instituto de Química, Universidade Federal do Rio Grande do Sul, CEP 91501-970, Porto Alegre, RS, Brazil
| | - P A Netz
- Instituto de Química, Universidade Federal do Rio Grande do Sul, CEP 91501-970, Porto Alegre, RS, Brazil
| | - M C Barbosa
- Instituto de Física, Departamento de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS, Brazil
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11
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Zavadlav J, Marrink SJ, Praprotnik M. SWINGER: a clustering algorithm for concurrent coupling of atomistic and supramolecular liquids. Interface Focus 2019; 9:20180075. [PMID: 31065343 PMCID: PMC6501350 DOI: 10.1098/rsfs.2018.0075] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/01/2019] [Indexed: 12/11/2022] Open
Abstract
In this contribution, we review recent developments and applications of a dynamic clustering algorithm SWINGER tailored for the multiscale molecular simulations of biomolecular systems. The algorithm on-the-fly redistributes solvent molecules among supramolecular clusters. In particular, we focus on its applications in combination with the adaptive resolution scheme, which concurrently couples atomistic and coarse-grained molecular representations. We showcase the versatility of our multiscale approach on a few applications to biomolecular systems coupling atomistic and supramolecular water models such as the well-established MARTINI and dissipative particle dynamics models and provide an outlook for future work.
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Affiliation(s)
- Julija Zavadlav
- Computational Science and Engineering Laboratory, ETH-Zurich, Clausiusstrasse 33, 8092 Zurich, Switzerland
| | - Siewert J. Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 7, 9747, AG Groningen, The Netherlands
| | - Matej Praprotnik
- Laboratory for Molecular Modeling, National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana, Slovenia
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12
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Popadić A, Svenšek D, Podgornik R, Praprotnik M. Density–Nematic Coupling in Isotropic Linear Polymers: Acoustic and Osmotic Birefringence. ADVANCED THEORY AND SIMULATIONS 2019. [DOI: 10.1002/adts.201900019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Aleksandar Popadić
- Laboratory for Molecular ModelingNational Institute of ChemistrySI‐1001 Ljubljana Slovenia
| | - Daniel Svenšek
- Department of Physics, Faculty of Mathematics and PhysicsUniversity of LjubljanaSI‐1000 Ljubljana Slovenia
| | - Rudolf Podgornik
- Department of Physics, Faculty of Mathematics and PhysicsUniversity of LjubljanaSI‐1000 Ljubljana Slovenia
- Department of Theoretical PhysicsJ. Stefan InstituteSI‐1000 Ljubljana Slovenia
- School of Physical Sciences and Kavli Institute for Theoretical SciencesUniversity of Chinese Academy of SciencesBeijing 100049 China
- CAS Key Laboratory of Soft Matter Physics, Institute of PhysicsChinese Academy of SciencesBeijing 100190 China
| | - Matej Praprotnik
- Laboratory for Molecular ModelingNational Institute of ChemistrySI‐1001 Ljubljana Slovenia
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13
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Delle Site L, Krekeler C, Whittaker J, Agarwal A, Klein R, Höfling F. Molecular Dynamics of Open Systems: Construction of a Mean‐Field Particle Reservoir. ADVANCED THEORY AND SIMULATIONS 2019. [DOI: 10.1002/adts.201900014] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Luigi Delle Site
- Freie Universität BerlinInstitute of MathematicsArnimallee 6 14195 Berlin Germany
| | - Christian Krekeler
- Freie Universität BerlinInstitute of MathematicsArnimallee 6 14195 Berlin Germany
| | - John Whittaker
- Freie Universität BerlinInstitute of MathematicsArnimallee 6 14195 Berlin Germany
| | - Animesh Agarwal
- Freie Universität BerlinInstitute of MathematicsArnimallee 6 14195 Berlin Germany
- Theoretical Biology and Biophysics GroupLos Alamos National LaboratoryLos Alamos NM 87545 USA
| | - Rupert Klein
- Freie Universität BerlinInstitute of MathematicsArnimallee 6 14195 Berlin Germany
| | - Felix Höfling
- Freie Universität BerlinInstitute of MathematicsArnimallee 6 14195 Berlin Germany
- Zuse Institute BerlinTakustr. 7 14195 Berlin Germany
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14
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Ciccotti G, Delle Site L. The physics of open systems for the simulation of complex molecular environments in soft matter. SOFT MATTER 2019; 15:2114-2124. [PMID: 30761396 DOI: 10.1039/c8sm02523a] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Molecular dynamics (MD) has become one of the most powerful tools of investigation in soft matter. Despite such success, simulations of large molecular environments are mostly run using the approximation of closed systems without the possibility of exchange of matter. Due to the molecular complexity of soft matter systems, an optimal simulation strategy would require the application of concurrent multiscale resolution approaches such that each part of a large system can be considered as an open subsystem at a high resolution embedded in a large coarser reservoir of energy and particles. This paper discusses the current capability and the future perspectives of multiscale adaptive resolution MD methods to satisfy the conceptual principles of open systems and to perform simulations of complex molecular environments in soft matter.
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Affiliation(s)
- Giovanni Ciccotti
- Instituto per le Applicazioni del Calcolo, Consiglio Nazionale delle Ricerche, and Universita' La Sapienza, Rome, Italy.
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15
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Friedman R. Simulations of Biomolecules in Electrolyte Solutions. ADVANCED THEORY AND SIMULATIONS 2019. [DOI: 10.1002/adts.201800163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Ran Friedman
- Department of Chemistry and Biomedical SciencesLinnæus UniversityKalmar SE‐391 82 Sweden
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16
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Sticking and stacking: Persistent ordering of fragmented DNA analogs. Proc Natl Acad Sci U S A 2018; 115:8652-8654. [PMID: 30093389 DOI: 10.1073/pnas.1810662115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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17
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Popadić A, Svenšek D, Podgornik R, Daoulas KC, Praprotnik M. Splay-density coupling in semiflexible main-chain nematic polymers with hairpins. SOFT MATTER 2018; 14:5898-5905. [PMID: 29972386 DOI: 10.1039/c8sm00835c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A main-chain nematic polymer melt/solution exhibits macroscopic orientational order of main polymer chains, i.e., a preferred (nematic) direction. It has long been known that in such polymeric liquid crystals spatial density/concentration variations and distortions of the nematic direction are coupled, obeying a vectorial continuity constraint whose rigidity increases with chain length. Its vectorial nature precludes the application to flexible chains, where backfolds (hairpins) are present and apolar nematic symmetry is manifest, which has been its puzzling feature from the beginning. We now establish a description of the splay-density coupling in the case of arbitrary backfolding, devising a continuity constraint for the "recovered" polar order of the chain tangents and introducing hairpins as its new type of sources. Performing detailed Monte Carlo simulations of nematic monodomain melts of "soft" worm-like chains with variable length and flexibility, we show via their structure factors that the weakening of the coupling due to the backfolding can be consistently quantified on the macroscopic level.
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Affiliation(s)
- Aleksandar Popadić
- Laboratory for Molecular Modeling, National Institute of Chemistry, SI-1001 Ljubljana, Slovenia
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18
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Krekeler C, Agarwal A, Junghans C, Praprotnik M, Delle Site L. Adaptive resolution molecular dynamics technique: Down to the essential. J Chem Phys 2018; 149:024104. [PMID: 30007373 DOI: 10.1063/1.5031206] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
We investigate the role of the thermodynamic (TD) force as an essential and sufficient technical ingredient for an efficient and accurate adaptive resolution algorithm. Such a force applied in the coupling region of an adaptive resolution molecular dynamics setup assures thermodynamic equilibrium between atomistically resolved and coarse-grained regions, allowing the proper exchange of molecules. We numerically prove that indeed for systems as relevant as liquid water and 1,3-dimethylimidazolium chloride ionic liquid, the combined action of the TD force and thermostat allows for computationally efficient and numerically accurate simulations, beyond the current capabilities of adaptive resolution setups, which employ switching functions in the coupling region.
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Affiliation(s)
| | - Animesh Agarwal
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Christoph Junghans
- Computer, Computational, and Statistical Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Matej Praprotnik
- Laboratory for Molecular Modeling, National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia and Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana, Slovenia
| | - Luigi Delle Site
- Institute for Mathematics, Freie Universität Berlin, Berlin, Germany
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Zavadlav J, Sablić J, Podgornik R, Praprotnik M. Open-Boundary Molecular Dynamics of a DNA Molecule in a Hybrid Explicit/Implicit Salt Solution. Biophys J 2018; 114:2352-2362. [PMID: 29650370 PMCID: PMC6129463 DOI: 10.1016/j.bpj.2018.02.042] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 02/24/2018] [Accepted: 02/28/2018] [Indexed: 12/24/2022] Open
Abstract
The composition and electrolyte concentration of the aqueous bathing environment have important consequences for many biological processes and can profoundly affect the behavior of biomolecules. Nevertheless, because of computational limitations, many molecular simulations of biophysical systems can be performed only at specific ionic conditions: either at nominally zero salt concentration, i.e., including only counterions enforcing the system's electroneutrality, or at excessive salt concentrations. Here, we introduce an efficient molecular dynamics simulation approach for an atomistic DNA molecule at realistic physiological ionic conditions. The simulations are performed by employing the open-boundary molecular dynamics method that allows for simulation of open systems that can exchange mass and linear momentum with the environment. In our open-boundary molecular dynamics approach, the computational burden is drastically alleviated by embedding the DNA molecule in a mixed explicit/implicit salt-bathing solution. In the explicit domain, the water molecules and ions are both overtly present in the system, whereas in the implicit water domain, only the ions are explicitly present and the water is described as a continuous dielectric medium. Water molecules are inserted and deleted into/from the system in the intermediate buffer domain that acts as a water reservoir to the explicit domain, with both water molecules and ions free to enter or leave the explicit domain. Our approach is general and allows for efficient molecular simulations of biomolecules solvated in bathing salt solutions at any ionic strength condition.
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Affiliation(s)
- Julija Zavadlav
- Computational Science & Engineering Laboratory, ETH Zurich, Zurich, Switzerland
| | - Jurij Sablić
- Laboratory for Molecular Modeling, National Institute of Chemistry, Ljubljana, Slovenia
| | - Rudolf Podgornik
- Theoretical Physics Department, J. Stefan Institute, Ljubljana, Slovenia; Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia
| | - Matej Praprotnik
- Laboratory for Molecular Modeling, National Institute of Chemistry, Ljubljana, Slovenia; Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia.
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Zavadlav J, Marrink SJ, Praprotnik M. Multiscale Simulation of Protein Hydration Using the SWINGER Dynamical Clustering Algorithm. J Chem Theory Comput 2018; 14:1754-1761. [PMID: 29439560 DOI: 10.1021/acs.jctc.7b01129] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
To perform computationally efficient concurrent multiscale simulations of biological macromolecules in solution, where the all-atom (AT) models are coupled to supramolecular coarse-grained (SCG) solvent models, previous studies resorted to modified AT water models, such as the bundled-simple point charge (SPC) models, that use semiharmonic springs to restrict the relative movement of water molecules within a cluster. Those models can have a significant impact on the simulated biomolecules and can lead, for example, to a partial unfolding of a protein. In this work, we employ the recently developed alternative approach with a dynamical clustering algorithm, SWINGER, which enables a direct coupling of original unmodified AT and SCG water models. We perform an adaptive resolution molecular dynamics simulation of a Trp-Cage miniprotein in multiscale water, where the standard SPC water model is interfaced with the widely used MARTINI SCG model, and demonstrate that, compared to the corresponding full-blown AT simulations, the structural and dynamic properties of the solvated protein and surrounding solvent are well reproduced by our approach.
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Affiliation(s)
- Julija Zavadlav
- Computational Science & Engineering Laboratory , ETH Zurich , Clausiusstrasse 33 , CH-8092 Zurich , Switzerland
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials , University of Groningen , Nijenborgh 7 , 9747 AG Groningen , The Netherlands
| | - Matej Praprotnik
- Laboratory for Molecular Modeling , National Institute of Chemistry , Hajdrihova 19 , SI-1001 Ljubljana , Slovenia.,Department of Physics, Faculty of Mathematics and Physics , University of Ljubljana , Jadranska 19 , SI-1000 Ljubljana , Slovenia
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