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  1. Book: Computational Modeling and Simulations of Biomolecular Systems

    Benoît Roux

    2021  

    Keywords Molecular Dynamics ; brownian dynamics ; Transition Rate
    Language English
    Size 210 p.
    Publisher WSPC
    Document type Book
    Note PDA Manuell_12
    Format 157 x 235 x 16
    ISBN 9789811232756 ; 981123275X
    Database PDA

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  2. Article ; Online: Transition rate theory, spectral analysis, and reactive paths.

    Roux, Benoît

    The Journal of chemical physics

    2022  Volume 156, Issue 13, Page(s) 134111

    Abstract: The kinetics of a dynamical system dominated by two metastable states is examined from the perspective of the activated-dynamics reactive flux formalism, Markov state eigenvalue spectral decomposition, and committor-based transition path theory. Analysis ...

    Abstract The kinetics of a dynamical system dominated by two metastable states is examined from the perspective of the activated-dynamics reactive flux formalism, Markov state eigenvalue spectral decomposition, and committor-based transition path theory. Analysis shows that the different theoretical formulations are consistent, clarifying the significance of the inherent microscopic lag-times that are implicated, and that the most meaningful one-dimensional reaction coordinate in the region of the transition state is along the gradient of the committor in the multidimensional subspace of collective variables. It is shown that the familiar reactive flux activated dynamics formalism provides an effective route to calculate the transition rate in the case of a narrow sharp barrier but much less so in the case of a broad flat barrier. In this case, the standard reactive flux correlation function decays very slowly to the plateau value that corresponds to the transmission coefficient. Treating the committor function as a reaction coordinate does not alleviate all issues caused by the slow relaxation of the reactive flux correlation function. A more efficient activated dynamics simulation algorithm may be achieved from a modified reactive flux weighted by the committor. Simulation results on simple systems are used to illustrate the various conceptual points.
    MeSH term(s) Algorithms ; Computer Simulation ; Kinetics
    Language English
    Publishing date 2022-04-08
    Publishing country United States
    Document type Journal Article
    ZDB-ID 3113-6
    ISSN 1089-7690 ; 0021-9606
    ISSN (online) 1089-7690
    ISSN 0021-9606
    DOI 10.1063/5.0084209
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  3. Article ; Online: Virtual Issue on Ion Channels and Ion Permeation.

    Roux, Benoît

    The journal of physical chemistry. B

    2021  Volume 125, Issue 28, Page(s) 7575–7577

    MeSH term(s) Ion Channel Gating ; Ion Channels
    Chemical Substances Ion Channels
    Language English
    Publishing date 2021-08-21
    Publishing country United States
    Document type Editorial
    ISSN 1520-5207
    ISSN (online) 1520-5207
    DOI 10.1021/acs.jpcb.1c05166
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: String Method with Swarms-of-Trajectories, Mean Drifts, Lag Time, and Committor.

    Roux, Benoît

    The journal of physical chemistry. A

    2021  Volume 125, Issue 34, Page(s) 7558–7571

    Abstract: The kinetics of a dynamical system comprising two metastable states is formulated in terms of a finite-time propagator in phase space (position and velocity) adapted to the underdamped Langevin equation. Dimensionality reduction to a subspace of ... ...

    Abstract The kinetics of a dynamical system comprising two metastable states is formulated in terms of a finite-time propagator in phase space (position and velocity) adapted to the underdamped Langevin equation. Dimensionality reduction to a subspace of collective variables yields familiar expressions for the propagator, committor, and steady-state flux. A quadratic expression for the steady-state flux between the two metastable states can serve as a robust variational principle to determine an optimal approximate committor expressed in terms of a set of collective variables. The theoretical formulation is exploited to clarify the foundation of the string method with swarms-of-trajectories, which relies on the mean drift of short trajectories to determine the optimal transition pathway. It is argued that the conditions for Markovity within a subspace of collective variables may not be satisfied with an arbitrary short time-step and that proper kinetic behaviors appear only when considering the effective propagator for longer lag times. The effective propagator with finite lag time is amenable to an eigenvalue-eigenvector spectral analysis, as elaborated previously in the context of position-based Markov models. The time-correlation functions calculated by swarms-of-trajectories along the string pathway constitutes a natural extension of these developments. The present formulation provides a powerful theoretical framework to characterize the optimal pathway between two metastable states of a system.
    Language English
    Publishing date 2021-08-18
    Publishing country United States
    Document type Journal Article
    ISSN 1520-5215
    ISSN (online) 1520-5215
    DOI 10.1021/acs.jpca.1c04110
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  5. Article ; Online: Continuum Electrostatic Behavior of a 3D-RISM Theory.

    Roux, Benoît

    The journal of physical chemistry. B

    2020  Volume 124, Issue 34, Page(s) 7444–7451

    Abstract: The electrostatic response underlying the 3D-RISM theory and its general relationship to models in which the solvent is represented in terms of a dielectric continuum are examined. It is found that the theory provides a coherent picture of solvation, ... ...

    Abstract The electrostatic response underlying the 3D-RISM theory and its general relationship to models in which the solvent is represented in terms of a dielectric continuum are examined. It is found that the theory provides a coherent picture of solvation, although its behavior is not entirely consistent with the trends that are expected in the limit of a large solute. The electrostatic discrepancy is due to the nature of the isotropic pair additive site-site correlation function associated with the susceptibility response of the uniform fluid. The influence of the discrepancy in the magnitude of the solvation free energy is negligible for a solvent with a large dielectric constant.
    Language English
    Publishing date 2020-08-17
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ISSN 1520-5207
    ISSN (online) 1520-5207
    DOI 10.1021/acs.jpcb.0c05519
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  6. Article ; Online: Simulating the Fluorescence of the Locally Excited State of DMABN in Solvents of Different Polarities.

    Youngworth, Rachael / Roux, Benoît

    The journal of physical chemistry. B

    2023  Volume 128, Issue 1, Page(s) 172–183

    Abstract: 4-( ...

    Abstract 4-(
    Language English
    Publishing date 2023-12-19
    Publishing country United States
    Document type Journal Article
    ISSN 1520-5207
    ISSN (online) 1520-5207
    DOI 10.1021/acs.jpcb.3c02975
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  7. Article ; Online: Simulating the Voltage-Dependent Fluorescence of Di-8-ANEPPS in a Lipid Membrane.

    Youngworth, Rachael / Roux, Benoît

    The journal of physical chemistry letters

    2023  Volume 14, Issue 36, Page(s) 8268–8276

    Abstract: Voltage-sensitive fluorescent dyes such as di-8-ANEPPS (di-8-aminonaphthylethylenepyridinium propylsulfonate) are powerful tools to study biological membranes. Its fluorescence is affected by changes in the membrane potential and other factors, requiring ...

    Abstract Voltage-sensitive fluorescent dyes such as di-8-ANEPPS (di-8-aminonaphthylethylenepyridinium propylsulfonate) are powerful tools to study biological membranes. Its fluorescence is affected by changes in the membrane potential and other factors, requiring extensive calibration to extract meaningful quantitative results. The amphiphilic di-8-ANEPPS molecule is expected to bind at the membrane-solution interface. However, atomic-level information is sparse about its position and orientation in the membrane, especially in regards to how the latter dynamically fluctuates to affect the observed fluorescence. In the present work, molecular dynamics simulations of the ground and excited states of di-8-ANEPPS embedded in a DPPC membrane as represented by classical force fields were used to investigate how the fluorescence is affected by externally applied potential. The calculations reproduce the shifts in the wavelength of emission as a function of voltage that are observed experimentally, indicating that the approach can help better understand the various factors that can affect the fluorescence of membrane-bound dyes.
    MeSH term(s) Membranes ; Cell Membrane ; Fluorescent Dyes ; Lipids
    Chemical Substances 1-(3-sulfonatopropyl)-4-(beta-(2-(di-n-octylamino)-6-naphthyl)vinyl)pyridinium betaine ; Fluorescent Dyes ; Lipids
    Language English
    Publishing date 2023-09-07
    Publishing country United States
    Document type Journal Article
    ISSN 1948-7185
    ISSN (online) 1948-7185
    DOI 10.1021/acs.jpclett.3c01257
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  8. Article ; Online: Simulating the Fluorescence of Di-8-ANEPPS in Solvents of Different Polarity.

    Youngworth, Rachael / Roux, Benoît

    The journal of physical chemistry. B

    2023  Volume 128, Issue 1, Page(s) 184–192

    Abstract: Voltage-sensitive fluorescent probes, such as di-8-amino-naphthyl-ethylene-pyridinium-propyl-sulfonate (di-8-ANEPPS), are extremely useful for monitoring the membrane potential in biological and biophysical studies. However, because di-8-ANEPPS is very ... ...

    Abstract Voltage-sensitive fluorescent probes, such as di-8-amino-naphthyl-ethylene-pyridinium-propyl-sulfonate (di-8-ANEPPS), are extremely useful for monitoring the membrane potential in biological and biophysical studies. However, because di-8-ANEPPS is very sensitive to its environment, it can be difficult to distinguish the degree to which a given external factor affects the observed fluorescence. Molecular dynamics simulations based on detailed atomic models make it possible to examine the particular characteristics of the system and predict the effects of the surroundings. Here, the sensitivity of the spectra of di-8-ANEPPS to solvent polarity is investigated by modeling the electronic transition between the ground and excited states using classical molecular mechanical force fields. The absorption and emission of di-8-ANEPPS were simulated in 12 solvents of increasing polarity using nonpolarizable and polarizable force fields. While the computational results and experimental data do not match perfectly, classical Lippert plots of both models show the expected increase of the Stokes shift of di-8-ANEPPS with the orientation polarizability of the surrounding solvent.
    Language English
    Publishing date 2023-12-19
    Publishing country United States
    Document type Journal Article
    ISSN 1520-5207
    ISSN (online) 1520-5207
    DOI 10.1021/acs.jpcb.3c02974
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  9. Article ; Online: Calculating the Effect of Membrane Thickness on the Lifetime of the Gramicidin A Channel: A Landmark.

    Roux, Benoît

    Biophysical journal

    2019  Volume 117, Issue 10, Page(s) 1779–1780

    MeSH term(s) Dimerization ; Gramicidin ; Ion Channels ; Lipid Bilayers
    Chemical Substances Ion Channels ; Lipid Bilayers ; Gramicidin (1405-97-6)
    Language English
    Publishing date 2019-10-10
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Comment
    ZDB-ID 218078-9
    ISSN 1542-0086 ; 0006-3495
    ISSN (online) 1542-0086
    ISSN 0006-3495
    DOI 10.1016/j.bpj.2019.10.005
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  10. Article ; Online: Configurational Sampling of All-Atom Solvated Membranes Using Hybrid Nonequilibrium Molecular Dynamics Monte Carlo Simulations.

    Szczepaniak, Florence / Dehez, François / Roux, Benoît

    The journal of physical chemistry letters

    2024  Volume 15, Issue 14, Page(s) 3796–3804

    Abstract: All-atom simulations are a powerful approach to study the structure and dynamics of biological membranes. However, sampling the atomic configurations of inhomogeneous membranes can be challenging due to the slow lateral diffusion of the various ... ...

    Abstract All-atom simulations are a powerful approach to study the structure and dynamics of biological membranes. However, sampling the atomic configurations of inhomogeneous membranes can be challenging due to the slow lateral diffusion of the various constituents. To address this issue, a hybrid nonequilibrium molecular dynamics Monte Carlo (neMD/MC) simulation method is proposed in which randomly chosen lipid molecules are swapped to generate configurations that are subsequently accepted or rejected according to a Metropolis criterion based on the alchemical work for the attempted swap calculated via a short trajectory. A dual-topology framework constraining the common atoms of the exchanging molecules yields a good acceptance probability using switching trajectories as short as 10 ps. The performance of the hybrid neMD/MC algorithm and its ability to sample the distribution of lipids near a transmembrane helix carrying a net charge are illustrated for a binary mixture of charged and zwitterionic lipids.
    Language English
    Publishing date 2024-04-01
    Publishing country United States
    Document type Journal Article
    ISSN 1948-7185
    ISSN (online) 1948-7185
    DOI 10.1021/acs.jpclett.4c00305
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