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Yang R, Bernardino K, Xiao X, Gomes WR, Mattoso DA, Kotov NA, Bogdan P, de Moura AF. Graph Theoretical Description of Phase Transitions in Complex Multiscale Phases with Supramolecular Assemblies. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2402464. [PMID: 38952077 DOI: 10.1002/advs.202402464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 05/15/2024] [Indexed: 07/03/2024]
Abstract
Phase transitions are typically quantified using order parameters, such as crystal lattice distances and radial distribution functions, which can identify subtle changes in crystalline materials or high-contrast phases with large structural differences. However, the identification of phases with high complexity, multiscale organization and of complex patterns during the structural fluctuations preceding phase transitions, which are essential for understanding the system pathways between phases, is challenging for those traditional analyses. Here, it is shown that for two model systems- thermotropic liquid crystals and a lyotropic water/surfactant mixtures-graph theoretical (GT) descriptors can successfully identify complex phases combining molecular and nanoscale levels of organization that are hard to characterize with traditional methodologies. Furthermore, the GT descriptors also reveal the pathways between the different phases. Specifically, centrality parameters and node-based fractal dimension quantify the system behavior preceding the transitions, capturing fluctuation-induced breakup of aggregates and their long-range cooperative interactions. GT parameterization can be generalized for a wide range of chemical systems and be instrumental for the growth mechanisms of complex nanostructures.
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Affiliation(s)
- Ruochen Yang
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA, 90089, USA
- Center of Complex Particle Systems (COMPASS), Ann Arbor, MI, 48109-2102, USA
| | - Kalil Bernardino
- Department of Chemistry, Federal University of São Carlos, São Carlos, SP, 13565-905, Brazil
| | - Xiongye Xiao
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA, 90089, USA
- Center of Complex Particle Systems (COMPASS), Ann Arbor, MI, 48109-2102, USA
| | - Weverson R Gomes
- Department of Chemistry, Federal University of São Carlos, São Carlos, SP, 13565-905, Brazil
| | - Davi A Mattoso
- Department of Chemistry, Federal University of São Carlos, São Carlos, SP, 13565-905, Brazil
| | - Nicholas A Kotov
- Center of Complex Particle Systems (COMPASS), Ann Arbor, MI, 48109-2102, USA
- Department of Chemical Engineering, Department of Materials Science and Engineering, Biointerfaces Institute, University of Michigan, Ann Arbor, MI, 48109-2102, USA
| | - Paul Bogdan
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA, 90089, USA
- Center of Complex Particle Systems (COMPASS), Ann Arbor, MI, 48109-2102, USA
| | - André F de Moura
- Department of Chemistry, Federal University of São Carlos, São Carlos, SP, 13565-905, Brazil
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Eliasquevici R, Bernardino K. Counter-ion adsorption and electrostatic potential in sodium and choline dodecyl sulfate micelles - a molecular dynamics simulation study. J Mol Model 2024; 30:101. [PMID: 38467947 DOI: 10.1007/s00894-024-05897-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 03/03/2024] [Indexed: 03/13/2024]
Abstract
CONTEXT Choline-based surfactants are interesting both from the practical point of view to obtaining environmental-friendly surfactants as well as from the theoretical side since the interactions between the choline and surfactants can help to understand self-assembly phenomena in deep eutectic solvents. Although no significant change was noticed in the micelle size and shape due to the exchange of the sodium counter-ion by choline in our simulations, the adsorption of the choline cation over the micelle surface is stronger than the adsorption of the sodium, which leads to a reduction of the exposed surface area of the micelle and remarkable effects over the electrostatic potential. The choline neutralizes the surface charge of the surfactant better than sodium; however, this is partially compensated by a stronger water orientation around the SDS micelle. The balance between the contributions from the surfactant, the counter-ion, and water to the electrostatic potential leads to a complex pattern with alternate regions of positive and negative potential at the micelle/water interface which can be important to the incorporation of other charged species at the micelle surface as well as for the interaction between micelles in solution. METHODS To evaluate the effects of the counter-ion substitution, micelles of sodium dodecyl sulfate (SDS) and choline dodecyl sulfate (ChDS) were studied and compared by means of molecular dynamics simulations in aqueous solution. In both cases, the simulations started from pre-assembled micelles with 60 dodecyl sulfate ions and 240-ns simulations were performed at NPT ensemble at T = 323.15 K and P = 1 bar using the Gromacs software with the OPLS-AA force field to describe dodecyl sulfate and choline, Åqvist parameters for sodium, and SPC model for water molecules.
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Affiliation(s)
- Rafaela Eliasquevici
- Laboratório de Química Computacional, Departamento de Química, Universidade Federal de São Carlos, Rod. Washington Luiz S/N, São Carlos, 13565-905, Brazil
| | - Kalil Bernardino
- Laboratório de Química Computacional, Departamento de Química, Universidade Federal de São Carlos, Rod. Washington Luiz S/N, São Carlos, 13565-905, Brazil.
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Tamucci JD, Alder NN, May ER. Peptide Power: Mechanistic Insights into the Effect of Mitochondria-Targeted Tetrapeptides on Membrane Electrostatics from Molecular Simulations. Mol Pharm 2023; 20:6114-6129. [PMID: 37904323 PMCID: PMC10841697 DOI: 10.1021/acs.molpharmaceut.3c00480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2023]
Abstract
Mitochondrial dysfunction is implicated in nine of the ten leading causes of death in the US, yet there are no FDA-approved therapeutics to treat it. Synthetic mitochondria-targeted peptides (MTPs), including the lead compound SS-31, offer promise, as they have been shown to restore healthy mitochondrial function and treat a variety of common diseases. At the cellular level, research has shown that MTPs accumulate strongly at the inner mitochondrial membrane (IMM), slow energy sinks (e.g., proton leaks), and improve ATP production. Modulation of electrostatic fields around the IMM has been implicated as a key aspect in the mechanism of action (MoA) of these peptides; however, molecular and mechanistic details have remained elusive. In this study, we employed all-atom molecular dynamics simulations (MD) to investigate the interactions of four MTPs with lipid bilayers and calculate their effect on structural and electrostatic properties. In agreement with previous experimental findings, we observed the modulation of the membrane surface and dipole potentials by MTPs. The simulations reveal that the MTPs achieve a reduction in the dipole potential by acting to disorder both lipid head groups and water layers proximal to the bilayer surface. We also find that MTPs decrease the bilayer thickness and increase the membrane's capacitance. These changes suggest that MTPs may enhance how much potential energy can be stored across the IMM at a given transmembrane potential difference. The MTPs also displace cations away from the bilayer surface, modulating the surface potential and offering an alternative mechanism for how these MTPs reduce mitochondrial energy sinks like proton leaks and mitigate Ca2+ accumulation stress. In conclusion, this study highlights the therapeutic potential of MTPs and underlines how interactions of MTPs with lipid bilayers serve as a fundamental component of their MoA.
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Affiliation(s)
- Jeffrey D Tamucci
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Nathan N Alder
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Eric R May
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269, United States
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Su L, Sun J, Ding F, Gao X, Zheng L. Effect of molecular structure on synergism in mixed zwitterionic/anionic surfactant system: An experimental and simulation study. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.114933] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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