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Bursik B, Eller J, Gross J. Predicting Solvation Free Energies from the Minnesota Solvation Database Using Classical Density Functional Theory Based on the PC-SAFT Equation of State. J Phys Chem B 2024; 128:3677-3688. [PMID: 38579126 DOI: 10.1021/acs.jpcb.3c07447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2024]
Abstract
We critically assess the capabilities of classical density functional theory (DFT) based on the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state to predict the solvation free energies of small molecules in various hydrocarbon solvents. We compare DFT results with experimental data from the Minnesota solvation database and utilize statistical methods to analyze the accuracy of our approach, as well as its weaknesses. The mean absolute error of the solvation free energies is 3.7 kJ mol-1 for n-alkane solvents, ranging from pentane to hexadecane, with 473 solute-solvent systems. For solvents consisting of cyclic hydrocarbons (cyclohexane, benzene, toluene, and ethylbenzene) with 245 solute-solvent systems, we report a slightly larger mean absolute error of 4.2 kJ mol-1. We identify three possible sources of errors: (i) the neglect of solute-solvent and solvent-solvent Coulomb interactions, which limits the applicability of PC-SAFT DFT to nonpolar and weakly polar molecules; (ii) the solute's Lennard-Jones parameters supplied by the general AMBER force field, which are not parametrized toward solvation free energies; and (iii) the application of the Lorentz-Berthelot combining rules to the dispersive interactions between a segment of the PC-SAFT solvent and a Lennard-Jones interaction site of the solute. The approach is more accurate than standard implementations of phenomenological models in common chemistry software packages, which exhibit mean absolute errors larger than 9.12 kJ mol-1, even though newer phenomenological models achieve a mean absolute error of about 2 kJ mol-1. PC-SAFT DFT is more computationally efficient than state of the art explicit molecular simulations in combination with free energy perturbation methods. It is predictive with respect to solvation free energies, i.e., the input for the model is the (element-specific) molecular force field, the solute configuration from molecular dynamics simulations, and the (substance-specific) PC-SAFT parameters. The PC-SAFT parametrization uses pure-component data and does not require experimental solvation free energies. The PC-SAFT equation of state, without applying a DFT formalism, can also be used to calculate solvation free energies, provided that the PC-SAFT parameters for the solute are available. A large number of substances was recently parametrized by members of our group (Esper, T.; Bauer, G.; Rehner, P.; Gross, J. Ind. Eng. Chem. Res. 2023, 62), which enables a comparison to the DFT approach for 103 substances. Accurate results are obtained from the PC-SAFT equation of state with an MAE below 2.51 kJ mol-1. The DFT approach does not require PC-SAFT parameters for the solute and can be applied to all solutes that can be represented by the molecular force field.
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Affiliation(s)
- Benjamin Bursik
- Institute of Thermodynamics and Thermal Process Engineering, University of Stuttgart, Stuttgart 70569, Germany
| | - Johannes Eller
- Institute of Thermodynamics and Thermal Process Engineering, University of Stuttgart, Stuttgart 70569, Germany
| | - Joachim Gross
- Institute of Thermodynamics and Thermal Process Engineering, University of Stuttgart, Stuttgart 70569, Germany
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2
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Taylor A, Zhang S, Johannissen LO, Sakuma M, Phillips RS, Green AP, Hay S, Heyes DJ, Scrutton NS. Mechanistic implications of the ternary complex structural models for the photoenzyme protochlorophyllide oxidoreductase. FEBS J 2024; 291:1404-1421. [PMID: 38060334 DOI: 10.1111/febs.17025] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/13/2023] [Accepted: 12/05/2023] [Indexed: 04/04/2024]
Abstract
The photoenzyme protochlorophyllide oxidoreductase (POR) is an important enzyme for understanding biological H-transfer mechanisms. It uses light to catalyse the reduction of protochlorophyllide to chlorophyllide, a key step in chlorophyll biosynthesis. Although a wealth of spectroscopic data have provided crucial mechanistic insight, a structural rationale for POR photocatalysis has proved challenging and remains hotly debated. Recent structural models of the ternary enzyme-substrate complex, derived from crystal and electron microscopy data, show differences in the orientation of the protochlorophyllide substrate and the architecture of the POR active site, with significant implications for the catalytic mechanism. Here, we use a combination of computational and experimental approaches to investigate the compatibility of each structural model with the hypothesised reaction mechanisms and propose an alternative structural model for the cyanobacterial POR ternary complex. We show that a strictly conserved tyrosine, previously proposed to act as the proton donor in POR photocatalysis, is unlikely to be involved in this step of the reaction but is crucial for Pchlide binding. Instead, an active site cysteine is important for both hydride and proton transfer reactions in POR and is proposed to act as the proton donor, either directly or through a water-mediated network. Moreover, a conserved glutamine is important for Pchlide binding and ensuring efficient photochemistry by tuning its electronic properties, likely by interacting with the central Mg atom of the substrate. This optimal 'binding pose' for the POR ternary enzyme-substrate complex illustrates how light energy can be harnessed to facilitate enzyme catalysis by this unique enzyme.
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Affiliation(s)
- Aoife Taylor
- Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, UK
| | - Shaowei Zhang
- Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, UK
| | - Linus O Johannissen
- Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, UK
| | - Michiyo Sakuma
- Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, UK
| | - Robert S Phillips
- Departments of Chemistry and Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
| | - Anthony P Green
- Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, UK
| | - Sam Hay
- Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, UK
| | - Derren J Heyes
- Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, UK
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, UK
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3
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Xiao T, Zhou Y, Li B. Energy-Scaled Debye-Hückel Theory for the Electrostatic Solvation Free Energy in Size-Asymmetric Electrolyte Solutions. J Phys Chem B 2024; 128:1029-1039. [PMID: 38235680 DOI: 10.1021/acs.jpcb.3c07233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
In this report, an energy-scaled Debye-Hückel theory is developed for fast and accurate evaluation of the electrostatic solvation free energy in size-asymmetric electrolyte solutions. A size-asymmetric electrolyte solution is mapped to a dielectric continuum medium with Debye-Hückel-like response. Based on the scaling relation of the electrostatic energy of a spherical ion in the small and large size limits, a Padé polynomial is used to interpolate the electrostatic energy at finite size. The Padé polynomial is further interpreted as the electrostatic energy of an effective Debye-Hückel mean field model, depicted by a modified Debye parameter and a surface charge density due to the size asymmetry of the solvent ions. This theory can distinguish the electrostatic energies and the electrostatic solvation free energies of solutes with the same size but opposite charges. Application to charged hard and charged soft spheres demonstrates the accuracy of our approach.
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Affiliation(s)
- Tiejun Xiao
- Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Synergetic Innovation Center of Scientific Big Data for Advanced Manufacturing Technology, Guizhou Education University, Guiyang 550018, People's Republic of China
| | - Yun Zhou
- Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Synergetic Innovation Center of Scientific Big Data for Advanced Manufacturing Technology, Guizhou Education University, Guiyang 550018, People's Republic of China
| | - Bo Li
- Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Synergetic Innovation Center of Scientific Big Data for Advanced Manufacturing Technology, Guizhou Education University, Guiyang 550018, People's Republic of China
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4
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Zhao Z, Ma Y, Xie Z, Wu F, Fan J, Kou J. Molecular Mechanisms of the Generation and Accumulation of Gas at the Interface. Langmuir 2024. [PMID: 38293869 DOI: 10.1021/acs.langmuir.3c02701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Gas-evolving reactions are widespread in chemical and energy fields. However, the generated gas will accumulate at the interface, which reduces the rate of gas generation. Understanding the microscopic processes of the generation and accumulation of gas at the interface is crucial for improving the efficiency of gas generation. Here, we develop an algorithm to reproduce the process of catalytic gas generation at the molecular scale based on the all-atom molecular dynamics simulations and obtain the quantitative evolution of the gas generation, which agrees well with the experimental results. In addition, we demonstrate that under an external electric field, the generated gas molecules do not accumulate at the electrode surface, which implies that the electric field can significantly increase the rate of the gas generation. The results suggest that the external electric field changes the structure of the water molecules near the electrode surface, making it difficult for gas molecules to accumulate on the electrode surface. Furthermore, it is found that gas desorption from the electrode surface is an entropy-driven process, and its accumulation at the electrode surface depends mainly on the competition between the entropy and the enthalpy of the water molecules under the influence of the electric field. These results provide deep insight into gas generation and inhibition of gas accumulation.
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Affiliation(s)
- Zhigao Zhao
- Institute of Condensed Matter Physics, Zhejiang Institute of Photoelectronics & Zhejiang Institute for Advanced Light Source, Zhejiang Normal University, Jinhua 321004, China
| | - Yunqiu Ma
- Institute of Condensed Matter Physics, Zhejiang Institute of Photoelectronics & Zhejiang Institute for Advanced Light Source, Zhejiang Normal University, Jinhua 321004, China
| | - Zhang Xie
- Institute of Condensed Matter Physics, Zhejiang Institute of Photoelectronics & Zhejiang Institute for Advanced Light Source, Zhejiang Normal University, Jinhua 321004, China
| | - Fengmin Wu
- Institute of Condensed Matter Physics, Zhejiang Institute of Photoelectronics & Zhejiang Institute for Advanced Light Source, Zhejiang Normal University, Jinhua 321004, China
| | - Jintu Fan
- Institute of Textiles and Clothing, The Hong Kong Polytechnic University Hung Hom, Kowloon, Hong Kong 999077, China
- Department of Fiber Science and Apparel Design, Cornell University, Ithaca, New York 14853-4401, United States
| | - Jianlong Kou
- Institute of Condensed Matter Physics, Zhejiang Institute of Photoelectronics & Zhejiang Institute for Advanced Light Source, Zhejiang Normal University, Jinhua 321004, China
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Kabedev A, Bergström CAS, Larsson P. Molecular dynamics study on micelle-small molecule interactions: developing a strategy for an extensive comparison. J Comput Aided Mol Des 2023; 38:5. [PMID: 38103089 PMCID: PMC10725378 DOI: 10.1007/s10822-023-00541-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 10/31/2023] [Indexed: 12/17/2023]
Abstract
Theoretical predictions of the solubilizing capacity of micelles and vesicles present in intestinal fluid are important for the development of new delivery techniques and bioavailability improvement. A balance between accuracy and computational cost is a key factor for an extensive study of numerous compounds in diverse environments. In this study, we aimed to determine an optimal molecular dynamics (MD) protocol to evaluate small-molecule interactions with micelles composed of bile salts and phospholipids. MD simulations were used to produce free energy profiles for three drug molecules (danazol, probucol, and prednisolone) and one surfactant molecule (sodium caprate) as a function of the distance from the colloid center of mass. To address the challenges associated with such tasks, we compared different simulation setups, including freely assembled colloids versus pre-organized spherical micelles, full free energy profiles versus only a few points of interest, and a coarse-grained model versus an all-atom model. Our findings demonstrate that combining these techniques is advantageous for achieving optimal performance and accuracy when evaluating the solubilization capacity of micelles. All-atom (AA) and coarse-grained (CG) umbrella sampling (US) simulations and point-wise free energy (FE) calculations were compared to their efficiency to computationally analyze the solubilization of active pharmaceutical ingredients in intestinal fluid colloids.
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Affiliation(s)
| | - Christel A S Bergström
- Department of Pharmacy, Uppsala University, Uppsala, Sweden
- Swedish Drug Delivery Center, Uppsala University, Uppsala, Sweden
| | - Per Larsson
- Department of Pharmacy, Uppsala University, Uppsala, Sweden.
- Swedish Drug Delivery Center, Uppsala University, Uppsala, Sweden.
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6
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Ganjali Koli M, Fogolari F. Exploring the role of cyclodextrins as a cholesterol scavenger: a molecular dynamics investigation of conformational changes and thermodynamics. Sci Rep 2023; 13:21765. [PMID: 38066228 PMCID: PMC10709460 DOI: 10.1038/s41598-023-49217-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Accepted: 12/05/2023] [Indexed: 12/18/2023] Open
Abstract
This study presents a comprehensive analysis of the cholesterol binding mechanism and conformational changes in cyclodextrin (CD) carriers, namely βCD, 2HPβCD, and MβCD. The results revealed that the binding of cholesterol to CDs was spontaneous and thermodynamically favorable, with van der Waals interactions playing a dominant role, while Coulombic interactions have a negligible contribution. The solubility of cholesterol/βCD and cholesterol/MβCD complexes was lower compared to cholesterol/2HPβCD complex due to stronger vdW and Coulombic repulsion between water and CDs. Hydrogen bonding was found to have a minor role in the binding process. The investigation of mechanisms and kinetics of binding demonstrated that cholesterol permeates into the CD cavities completely. Replicas consideration indicated that while the binding to 2HPβCD occurred perpendicularly and solely through positioning cholesterol's oxygen toward the primary hydroxyl rim (PHR), the mechanism of cholesterol binding to βCD and MβCD could take place with the orientation of oxygen towards both rims. Functionalization resulted in decreased cavity polarity, increased constriction tendency, and altered solubility and configuration of the carrier. Upon cholesterol binding, the CDs expanded, increasing the cavity volume in cholesterol-containing systems. The effects of cholesterol on the relative shape anisotropy (κ2) and asphericity parameter (b) in cyclodextrins were investigated. βCD exhibited a spherical structure regardless of cholesterol presence, while 2HPβCD and MβCD displayed more pronounced non-sphericity in the absence of cholesterol. Loading cholesterol transformed 2HPβCD and MβCD into more spherical shapes, with increased probabilities of higher κ2. MβCD showed a higher maximum peak of κ2 compared to 2HPβCD after cholesterol loading, while 2HPβCD maintained a significant maximum peak at 0.2 for b.
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Affiliation(s)
- Mokhtar Ganjali Koli
- Department of Chemistry, University of Kurdistan, Sanandaj, Iran.
- Computational Chemistry Laboratory, Kask Afrand Exire Ltd., Sanandaj, Iran.
| | - Federico Fogolari
- Dipartimento di Scienze Matematiche Informatiche e Fisiche (DMIF), University of Udine, Via delle Scienze 206, 33100, Udine, Italy
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7
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Lin Q, Zhan Q, Wu Y, Wang J, Li L, Peng F, Xu F, Ren J. Molecular scale behavior of xylan during solvent-controlled extraction and precipitation. Phys Chem Chem Phys 2023; 25:28078-28085. [PMID: 37622227 DOI: 10.1039/d3cp01385e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
Abstract
Solvent-controlled extraction and precipitation are the most fundamental methods for obtaining hemicellulose from lignocellulosic biomass and purification processes. However, the dissolution and precipitation mechanisms involved have scarcely been mentioned. In this study, the molecular scale behavior of xylan-type hemicellulose during solvent-controlled extraction and precipitation is investigated using molecular dynamics (MD) simulations and density functional theory (DFT) calculations. To bring the model closer to the real extracted xylan, a high degree of polymerization (DP100) of xylan is established, and hemicelluloses with low DP (DP15 and DP50) are also investigated. Four phenomena are explained at the molecular level, including the influence of the polymerization degree and side chain on the solubility of xylan in water, the improvement of the xylan's solubility in NaOH, the precipitation of xylan in ethanol, and the acetyl group preservation of xylan in DMSO. This study contributes to an increased understanding of the dissolution and precipitation mechanisms of hemicellulose and provides a resource for the simulation of high DP hemicellulose, which gives a theoretical basis for the efficient extraction of high-purity hemicellulose as well as economic biorefining.
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Affiliation(s)
- Qixuan Lin
- State Key Laboratory of Pulp and Paper Engineering, School of Light Industry and Engineering, South China University of Technology, Guangzhou 510640, China.
| | - Qiwen Zhan
- State Key Laboratory of Pulp and Paper Engineering, School of Light Industry and Engineering, South China University of Technology, Guangzhou 510640, China.
| | - Yue Wu
- State Key Laboratory of Pulp and Paper Engineering, School of Light Industry and Engineering, South China University of Technology, Guangzhou 510640, China.
| | - Jianlin Wang
- State Key Laboratory of Pulp and Paper Engineering, School of Light Industry and Engineering, South China University of Technology, Guangzhou 510640, China.
| | - Libo Li
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
| | - Feng Peng
- Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, 100083, China
| | - Feng Xu
- Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, 100083, China
| | - Junli Ren
- State Key Laboratory of Pulp and Paper Engineering, School of Light Industry and Engineering, South China University of Technology, Guangzhou 510640, China.
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Sun B, Paraskevopoulos G, Min J, Rossdeutcher R, Ghosh S, Quinn B, Lin M, Sarkar D, Sukumaran D, Wang Y, Vávrová K, Lovell JF, Zhang Y. Topical Drug Delivery of Concentrated Cabazitaxel in an α-Tocopherol and DMSO Solution. Adv Sci (Weinh) 2023; 10:e2302658. [PMID: 37555802 PMCID: PMC10582425 DOI: 10.1002/advs.202302658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 07/03/2023] [Indexed: 08/10/2023]
Abstract
Topical chemotherapy approaches are relevant for certain skin cancer treatments. This study observes that cabazitaxel (CTX), a broad-spectrum second-generation taxane cytotoxic agent, can be dissolved in α-tocopherol at high concentrations exceeding 100 mg mL-1 . 2D nuclear magnetic resonance (NMR) analysis and molecular dynamics (MD) are used to study this phenomenon. The addition of 30% dimethyl sulfoxide (DMSO) to the α-tocopherol/CTX solution improves its working viscosity and enhances CTX permeation through human skin in vitro (over 5 µg cm-2 within 24 h), while no detectable drug permeates when CTX is dissolved in α-tocopherol alone. In a transepidermal water loss assay, the barrier impairment induced by CTX in 30% DMSO in α-tocopherol, but not in pure DMSO, is reversible 8 h after the formulation removal from the skin surface. Antitumor efficacy of the topical CTX formulation is evaluated in nude mice bearing A431 human squamous carcinoma skin cancer xenografts. With topical application of concentrated CTX solutions (75 mg mL-1 ), tumor growth is significantly suppressed compared to lower concentration groups (0, 25, or 50 mg mL-1 CTX). Taken together, these findings show that topical delivery of CTX using a DMSO and α-tocopherol solvent warrants further study as a treatment for skin malignancies.
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Affiliation(s)
- Boyang Sun
- School of Chemical Engineering and TechnologyKey Laboratory of Systems Bioengineering (Ministry of Education)Frontiers Science Center for Synthetic Biology (Ministry of Education)State Key Laboratory of Chemical EngineeringTianjin UniversityTianjin300350P. R. China
| | - Georgios Paraskevopoulos
- Skin Barrier Research GroupFaculty of PharmacyCharles UniversityAkademika Heyrovského 1203Hradec Králové50005Czech Republic
| | - Jiwei Min
- School of Chemical Engineering and TechnologyKey Laboratory of Systems Bioengineering (Ministry of Education)Frontiers Science Center for Synthetic Biology (Ministry of Education)State Key Laboratory of Chemical EngineeringTianjin UniversityTianjin300350P. R. China
| | - Robert Rossdeutcher
- Department of ChemistryState University of New York at BuffaloBuffaloNY14260USA
| | - Sanjana Ghosh
- Department of Biomedical EngineeringState University of New York at BuffaloBuffaloNY14260USA
| | - Breandan Quinn
- Department of Biomedical EngineeringState University of New York at BuffaloBuffaloNY14260USA
| | - Meng‐Hsuan Lin
- Department of Biomedical EngineeringState University of New York at BuffaloBuffaloNY14260USA
| | - Debanjan Sarkar
- Department of Biomedical EngineeringState University of New York at BuffaloBuffaloNY14260USA
| | - Dinesh Sukumaran
- Department of ChemistryState University of New York at BuffaloBuffaloNY14260USA
| | - Yuefei Wang
- School of Chemical Engineering and TechnologyKey Laboratory of Systems Bioengineering (Ministry of Education)Frontiers Science Center for Synthetic Biology (Ministry of Education)State Key Laboratory of Chemical EngineeringTianjin UniversityTianjin300350P. R. China
| | - Kateřina Vávrová
- Skin Barrier Research GroupFaculty of PharmacyCharles UniversityAkademika Heyrovského 1203Hradec Králové50005Czech Republic
| | - Jonathan F. Lovell
- Department of Biomedical EngineeringState University of New York at BuffaloBuffaloNY14260USA
| | - Yumiao Zhang
- School of Chemical Engineering and TechnologyKey Laboratory of Systems Bioengineering (Ministry of Education)Frontiers Science Center for Synthetic Biology (Ministry of Education)State Key Laboratory of Chemical EngineeringTianjin UniversityTianjin300350P. R. China
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9
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Lundborg M, Lidmar J, Hess B. On the Path to Optimal Alchemistry. Protein J 2023; 42:477-489. [PMID: 37651042 PMCID: PMC10480267 DOI: 10.1007/s10930-023-10137-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/04/2023] [Indexed: 09/01/2023]
Abstract
Alchemical free energy calculations have become a standard and widely used tool, in particular for calculating and comparing binding affinities of drugs. Although methods to compute such free energies have improved significantly over the last decades, the choice of path between the end states of interest is usually still the same as two decades ago. We will show that there is a fundamentally arbitrary, implicit choice of parametrization of this path. To address this, the notion of the length of a path or a metric is required. A metric recently introduced in the context of the accelerated weight histogram method also proves to be very useful here. We demonstrate that this metric can not only improve the efficiency of sampling along a given path, but that it can also be used to improve the actual choice of path. For a set of relevant use cases, the combination of these improvements can increase the efficiency of alchemical free energy calculations by up to a factor 16.
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Affiliation(s)
| | - Jack Lidmar
- Department of Physics, KTH Royal Institute of Technology, 10691, Stockholm, Sweden
| | - Berk Hess
- Department of Applied Physics, KTH Royal Institute of Technology, 10691, Stockholm, Science for Life Laboratory, Solna, Sweden.
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10
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Karwounopoulos J, Kaupang Å, Wieder M, Boresch S. Calculations of Absolute Solvation Free Energies with Transformato─Application to the FreeSolv Database Using the CGenFF Force Field. J Chem Theory Comput 2023; 19:5988-5998. [PMID: 37616333 PMCID: PMC10500982 DOI: 10.1021/acs.jctc.3c00691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Indexed: 08/26/2023]
Abstract
We recently introduced transformato, an open-source Python package for the automated setup of large-scale calculations of relative solvation and binding free energy differences. Here, we extend the capabilities of transformato to the calculation of absolute solvation free energy differences. After careful validation against the literature results and reference calculations with the PERT module of CHARMM, we used transformato to compute absolute solvation free energies for most molecules in the FreeSolv database (621 out of 642). The force field parameters were obtained with the program cgenff (v2.5.1), which derives missing parameters from the CHARMM general force field (CGenFF v4.6). A long-range correction for the Lennard-Jones interactions was added to all computed solvation free energies. The mean absolute error compared to the experimental data is 1.12 kcal/mol. Our results allow a detailed comparison between the AMBER and CHARMM general force fields and provide a more in-depth understanding of the capabilities and limitations of the CGenFF small molecule parameters.
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Affiliation(s)
- Johannes Karwounopoulos
- Faculty
of Chemistry, Institute of Computational Biological Chemistry, University of Vienna, Währingerstr. 17, 1090 Vienna, Austria
- Vienna
Doctoral School of Chemistry (DoSChem), University of Vienna, Währingerstr. 42, 1090 Vienna, Austria
| | - Åsmund Kaupang
- Department
of Pharmacy, Section for Pharmaceutical Chemistry, University of Oslo, 0316 Oslo, Norway
| | - Marcus Wieder
- Department
of Pharmaceutical Sciences, Pharmaceutical Chemistry Division, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Stefan Boresch
- Faculty
of Chemistry, Institute of Computational Biological Chemistry, University of Vienna, Währingerstr. 17, 1090 Vienna, Austria
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11
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Azizi K, Laio A, Hassanali A. Solvation thermodynamics from cavity shapes of amino acids. PNAS Nexus 2023; 2:pgad239. [PMID: 37545648 PMCID: PMC10400782 DOI: 10.1093/pnasnexus/pgad239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 07/07/2023] [Accepted: 07/17/2023] [Indexed: 08/08/2023]
Abstract
According to common physical chemistry wisdom, the solvent cavities hosting a solute are tightly sewn around it, practically coinciding with its van der Waals surface. Solvation entropy is primarily determined by the surface and the volume of the cavity while enthalpy is determined by the solute-solvent interaction. In this work, we challenge this picture, demonstrating by molecular dynamics simulations that the cavities surrounding the 20 amino acids deviate significantly from the molecular surface. Strikingly, the shape of the cavity alone can be used to predict the solvation free energy, entropy, enthalpy, and hydrophobicity. Solute-solvent interactions involving the different chemical moieties of the amino acid, determine indirectly the cavity shape, and the properties of the branches but do not have to be taken explicitly into account in the prediction model.
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Affiliation(s)
- Khatereh Azizi
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
| | - Alessandro Laio
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
- SISSA, Via Bonomea 265, I-34136 Trieste, Italy
| | - Ali Hassanali
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
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12
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Hu H, Yang W, Liu S. Efficient Computation of the Electrostatic Component of Solvation Free Energy via a Two-Point Padé Approximation. J Chem Theory Comput 2023. [PMID: 37438260 DOI: 10.1021/acs.jctc.3c00468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
We develop an efficient method to compute the electrostatic component of the solvation free energy via the two-point Padé approximation. The Padé approximant uses four parameters to describe the electrostatic free energy change of the solvation process, which could be readily determined from four thermodynamic properties obtained in two simulations, namely, the first- and second-order free energy gradients of any two states. Therefore, instead of sampling at multiple intermediate states, only two states, e.g., electrostatically fully solvated and desolvated, are needed to determine the Padé approximant and compute the corresponding free energy contribution. Applications to several model systems, including both neutral and charged species, show that the method can accurately produce electrostatic solvation free energy. The method would be very useful to save computational cost in applications in which accurate but expensive energy functions like quantum mechanics are used.
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Affiliation(s)
- Hao Hu
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Polaris Quantum Biotech Inc., Suite 205, 201 W Main St., Durham, North Carolina 27701, United States
| | - Weitao Yang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Shubin Liu
- Research Computing Center, University of North Carolina, Chapel Hill, North Carolina 27599-3420, United States
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
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Wang Y, Yang F, Yan D, Zeng Y, Wei B, Chen J, He W. Identification Mechanism of BACE1 on Inhibitors Probed by Using Multiple Separate Molecular Dynamics Simulations and Comparative Calculations of Binding Free Energies. Molecules 2023; 28:4773. [PMID: 37375328 DOI: 10.3390/molecules28124773] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 06/12/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023] Open
Abstract
β-amyloid cleaving enzyme 1 (BACE1) is regarded as an important target of drug design toward the treatment of Alzheimer's disease (AD). In this study, three separate molecular dynamics (MD) simulations and calculations of binding free energies were carried out to comparatively determine the identification mechanism of BACE1 for three inhibitors, 60W, 954 and 60X. The analyses of MD trajectories indicated that the presence of three inhibitors influences the structural stability, flexibility and internal dynamics of BACE1. Binding free energies calculated by using solvated interaction energy (SIE) and molecular mechanics generalized Born surface area (MM-GBSA) methods reveal that the hydrophobic interactions provide decisive forces for inhibitor-BACE1 binding. The calculations of residue-based free energy decomposition suggest that the sidechains of residues L91, D93, S96, V130, Q134, W137, F169 and I179 play key roles in inhibitor-BACE1 binding, which provides a direction for future drug design toward the treatment of AD.
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Affiliation(s)
- Yiwen Wang
- School of Information Science and Electrical Engineering, Shandong Jiaotong University, Jinan 250357, China
- School of Aeronautics, Shandong Jiaotong University, Jinan 250357, China
| | - Fen Yang
- School of Information Science and Electrical Engineering, Shandong Jiaotong University, Jinan 250357, China
| | - Dongliang Yan
- School of Information Science and Electrical Engineering, Shandong Jiaotong University, Jinan 250357, China
- School of Science, Shandong Jiaotong University, Jinan 250357, China
| | - Yalin Zeng
- School of Information Science and Electrical Engineering, Shandong Jiaotong University, Jinan 250357, China
| | - Benzheng Wei
- Center for Medical Artificial Intelligence, Shandong University of Traditional Chinese Medicine, Qingdao 266112, China
| | - Jianzhong Chen
- School of Information Science and Electrical Engineering, Shandong Jiaotong University, Jinan 250357, China
- School of Science, Shandong Jiaotong University, Jinan 250357, China
| | - Weikai He
- School of Information Science and Electrical Engineering, Shandong Jiaotong University, Jinan 250357, China
- School of Aeronautics, Shandong Jiaotong University, Jinan 250357, China
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14
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Wang N, DeFever RS, Maginn EJ. Alchemical Free Energy and Hamiltonian Replica Exchange Molecular Dynamics to Compute Hydrofluorocarbon Isotherms in Imidazolium-Based Ionic Liquids. J Chem Theory Comput 2023. [PMID: 37195874 DOI: 10.1021/acs.jctc.3c00206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Ionic liquids (ILs) have shown promise for applications that leverage differential gas solubility in an IL solvent, e.g., gas separations. Although most available literature provides Henry's law constants, the ability to efficiently estimate full isotherms is important for engineering design calculations. Molecular simulation can be used as a tool to predict full isotherms of gas in ILs. However, particle insertions or deletions in a charge-dense IL medium and the sluggish conformational dynamics of ILs present two sampling challenges for these systems. We therefore devised a method that uses Hamiltonian replica exchange (HREX) molecular dynamics (MD) combined with alchemical free energy calculations to compute full solubility isotherms of two different hydrofluorocarbons (HFCs) in imidazolium-based IL binary mixtures. This workflow is significantly faster than the Gibbs ensemble Monte Carlo (GEMC) simulations which fail to deal with the slow conformational relaxation caused by the sluggish dynamics of ILs. Multiple free energy estimators, including thermodynamic integration, free energy perturbation, and multistate Bennett acceptance ratio method, provided consistent results. Overall, the simulated Henry's law constant, isotherm curvature, and solubility trends match experimental results reasonably well. We close by calculating the full solubility isotherms of two HFCs in IL mixtures that have not been reported in the literature, demonstrating the potential of this method to be used for solubility prediction and setting the stage for future computational screening studies that search for the "best" IL to separate azeotropic HFC mixtures.
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Affiliation(s)
- Ning Wang
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Ryan S DeFever
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Edward J Maginn
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
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Abstract
A formula for cavity formation energy of a hard sphere in restricted primitive electrolyte solutions is derived based on the integral equation theory. Specifically, the contact values of radial distribution functions between the hard sphere and the ionic species, determined analytically from the first-order mean spherical approximation theory, are used to evaluate the cavity formation energy. In the large solute-size limit, the scaling relation of the cavity formation energy further leads to an analytical expression for the surface tension of the electrolyte solution near a curved interface. Our theory is applied to hard spheres immersed in restricted primitive electrolyte solutions, where the good agreement of the cavity formation energy with the hyper-netted chain theory demonstrates the accuracy of our theory.
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Affiliation(s)
- Tiejun Xiao
- Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Synergetic Innovation Center of Scientific Big Data for Advanced Manufacturing Technology, Guizhou Education University, Guiyang 550018, People's Republic of China.
| | - Yun Zhou
- Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Synergetic Innovation Center of Scientific Big Data for Advanced Manufacturing Technology, Guizhou Education University, Guiyang 550018, People's Republic of China.
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Martins GF, Nascimento C, Galamba N. Mechanistic Insights into Polyphenols' Aggregation Inhibition of α-Synuclein and Related Peptides. ACS Chem Neurosci 2023; 14:1905-1920. [PMID: 37125909 DOI: 10.1021/acschemneuro.3c00162] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
While several polyphenols were found to either inhibit or modulate the aggregation of proteins implicated in neurodegenerative diseases, such as Parkinson's disease (PD), discrepant action mechanisms have been reported. This, in addition to some polyphenols' pan-assay interference compounds' reputation, casts some doubts concerning their therapeutic relevance. Here, we studied, through molecular dynamics and enhanced sampling methods, the aggregation of 11-mer peptides from the non-amyloid-β component, an aggregation-prone domain of α-synuclein (α-syn) implicated in PD and other synucleinopathies, in neat water and aqueous solutions of resveratrol (RSV) and gallic acid (GA). Further, simulations of the complete protein were carried out in aqueous urea, RSV, and GA solutions. Our results show that peptide aggregation is not disrupted by either phenolic compound. Thus, instead, intrusion of RSV and GA in the inter-peptide region induces a peptide-peptide re-orientation, favoring terminal interactions that manifest in the formation of barrierless solvent-separated configurations. Moreover, although the (poly)phenols induce a pronounced peptide dewetting at high concentrations, β-sheet-rich regions, a hallmark of α-syn aggregation, are not disrupted. Thus, our results indicate that, if anything, RSV and GA delay or modulate peptide aggregation at high concentrations via the stabilization of solvent-separated conformations as opposed to aggregation inhibition. Structural analysis of the full protein, however, shows that the (poly)phenols induce more extended conformations of α-syn, similar to urea, possibly also influencing its aggregation propensity. However, opposite to urea, the (poly)phenols reduce α-syn's conformational space, likely due to steric effects and a slowdown of the solvent dynamics. These effects are concentration-dependent and possibly unattainable at therapeutic-relevant concentrations. These results suggest that the aggregation inhibition activity of RSV and GA in vitro should involve, instead, either the non-covalent binding to oligomeric intermediates or the stabilization of the monomer and/or oligomers through the formation of covalent bonds of the respective quinones with α-syn. In addition, the enhanced aggregation tendency of the peptides observed here could be associated with the formation of non-toxic oligomers, reported for some polyphenols.
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Affiliation(s)
- G F Martins
- BioISI─Biosystems and Integrative Sciences Institute, Faculty of Sciences of the University of Lisbon, C8, Campo Grande, Lisbon 1749-016, Portugal
| | - C Nascimento
- BioISI─Biosystems and Integrative Sciences Institute, Faculty of Sciences of the University of Lisbon, C8, Campo Grande, Lisbon 1749-016, Portugal
| | - N Galamba
- BioISI─Biosystems and Integrative Sciences Institute, Faculty of Sciences of the University of Lisbon, C8, Campo Grande, Lisbon 1749-016, Portugal
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Wang L, Wang Y, Yu Y, Liu D, Zhao J, Zhang L. Deciphering Selectivity Mechanism of BRD9 and TAF1(2) toward Inhibitors Based on Multiple Short Molecular Dynamics Simulations and MM-GBSA Calculations. Molecules 2023; 28:molecules28062583. [PMID: 36985555 PMCID: PMC10052767 DOI: 10.3390/molecules28062583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/06/2023] [Accepted: 03/09/2023] [Indexed: 03/14/2023] Open
Abstract
BRD9 and TAF1(2) have been regarded as significant targets of drug design for clinically treating acute myeloid leukemia, malignancies, and inflammatory diseases. In this study, multiple short molecular dynamics simulations combined with the molecular mechanics generalized Born surface area method were employed to investigate the binding selectivity of three ligands, 67B, 67C, and 69G, to BRD9/TAF1(2) with IC50 values of 230/59 nM, 1400/46 nM, and 160/410 nM, respectively. The computed binding free energies from the MM-GBSA method displayed good correlations with that provided by the experimental data. The results indicate that the enthalpic contributions played a critical factor in the selectivity recognition of inhibitors toward BRD9 and TAF1(2), indicating that 67B and 67C could more favorably bind to TAF1(2) than BRD9, while 69G had better selectivity toward BRD9 over TAF1(2). In addition, the residue-based free energy decomposition approach was adopted to calculate the inhibitor–residue interaction spectrum, and the results determined the gatekeeper (Y106 in BRD9 and Y1589 in TAF1(2)) and lipophilic shelf (G43, F44, and F45 in BRD9 and W1526, P1527, and F1528 in TAF1(2)), which could be identified as hotspots for designing efficient selective inhibitors toward BRD9 and TAF1(2). This work is also expected to provide significant theoretical guidance and insightful molecular mechanisms for the rational designs of efficient selective inhibitors targeting BRD9 and TAF1(2).
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Ling H, Wang L, Lin Q, Huang Q, Zhang X, Ren J, Li N, Zhou C, Lin Z, Zhou J, Wei W, Wang X. Antimicrobial cellulose paper tuned with chitosan fibers for high-flux oil/water separation. Carbohydr Polym 2023; 312:120794. [PMID: 37059534 DOI: 10.1016/j.carbpol.2023.120794] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/02/2023] [Accepted: 03/05/2023] [Indexed: 03/11/2023]
Abstract
Separating films with both high efficiency and large flux are desperately needed to meet the rising demand for the treatment of oily wastewater, while traditional oil/water separation papers with high separation efficiency usually suffered from low flux due to the unsuitable size of filtration pores. Herein, we report a bio-based porous, superhydrophobic, and antimicrobial hybrid cellulose paper with tunable porous structures for high flux oil/water separation. The size of pores in the hybrid paper can be tuned by both physical supports provided by the chitosan fibers and the chemical shielding supplied by the hydrophobic modification. The hybrid paper with increased porosity (20.73 μm; 35.15 %) and excellent antibacterial properties can efficiently separate a wide range of oil/water mixtures, solely by gravity, with outstanding flux (maximum of 23,692.69 L m-2 h-1), tiny oil interception, and high efficiency of over 99 %. This work provides new sights in the development of durable and low-cost functional papers for rapid and efficient oil/water separation.
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Liu Q, Perez A. Assessing a computational pipeline to identify binding motifs to the α2 β1 integrin. Front Chem 2023; 11:1107400. [PMID: 36860646 PMCID: PMC9968975 DOI: 10.3389/fchem.2023.1107400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/27/2023] [Indexed: 02/16/2023] Open
Abstract
Integrins in the cell surface interact with functional motifs found in the extracellular matrix (ECM) that queue the cell for biological actions such as migration, adhesion, or growth. Multiple fibrous proteins such as collagen or fibronectin compose the ECM. The field of biomechanical engineering often deals with the design of biomaterials compatible with the ECM that will trigger cellular response (e.g., in tissue regeneration). However, there are a relative few number of known integrin binding motifs compared to all the possible peptide epitope sequences available. Computational tools could help identify novel motifs, but have been limited by the challenges in modeling the binding to integrin domains. We revisit a series of traditional and novel computational tools to assess their performance in identifying novel binding motifs for the I-domain of the α2β1 integrin.
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Affiliation(s)
- Qianchen Liu
- Department of Chemistry and Quantum Theory Project, University of Florida, Gainesville, FL, United States
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20
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Dongmo Foumthuim CJ, Giacometti A. Solvent quality and solvent polarity in polypeptides. Phys Chem Chem Phys 2023; 25:4839-4853. [PMID: 36692363 DOI: 10.1039/d2cp05214h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Using molecular dynamics and thermodynamic integration, we report on the solvation process of seven polypeptides (GLY, ALA, ILE, ASN, LYS, ARG, GLU) in water and in cyclohexane. The polypeptides are selected to cover the full hydrophobic scale while varying their chain length from tri- to undeca-homopeptides, providing indications on possible non-additivity effects as well as the role of the peptide backbone in the overall stability of the polypeptides. The use of different solvents and different polypeptides allows us to investigate the relation between solvent quality - the capacity of a given solvent to fold/unfold a given biopolymer often described on a scale ranging from "good" to "poor"; and solvent polarity - related to the specific interactions of any solvent with respect to a reference solvent. Undeca-glycine is found to be the only polypeptide to have a stable collapse in water (polar solvent), with the other hydrophobic polypeptides displaying repeated folding and unfolding events in water, with polar polypeptides presenting even more complex behavior. By contrast, all polypeptides are found to keep an extended conformation in cyclohexane, irrespective of their polarity. All considered polypeptides are also found to have favorable solvation free energy independent of the solvent polarity and their intrinsic hydrophobicity, clearly highlighting the prominent stabilizing role of the peptide backbone - with the solvation process largely enthalpically dominated in polar polypeptides and partially entropically driven for hydrophobic polypeptides. Our study thus reveals the complexity of the solvation process of polypeptides defying the common view "like dissolves like", with the solute polarity playing the most prominent role. The absence of mirror symmetry upon the inversion of polarities of both the solvent and the polypeptides is confirmed.
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Affiliation(s)
- Cedrix J Dongmo Foumthuim
- Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari di Venezia, Campus Scientifico, Edificio Alfa, via Torino 155, 30172 Venezia Mestre, Italy.
| | - Achille Giacometti
- Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari di Venezia, Campus Scientifico, Edificio Alfa, via Torino 155, 30172 Venezia Mestre, Italy. .,European Centre for Living Technology (ECLT) Ca Bottacin, Dorsoduro 3911, Calle Crosera 30123 Venice, Italy
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Bhatta T, Khanal P, Khanal SP, Adhikari NP. Thermodynamics and Transport Properties of Valine and Cysteine Peptides in Water. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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22
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Wang L, Lu D, Wang Y, Xu X, Zhong P, Yang Z. Binding selectivity-dependent molecular mechanism of inhibitors towards CDK2 and CDK6 investigated by multiple short molecular dynamics and free energy landscapes. J Enzyme Inhib Med Chem 2023; 38:84-99. [DOI: 10.1080/14756366.2022.2135511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Lifei Wang
- School of Science, Shandong Jiaotong University, Jinan, PR China
| | - Dan Lu
- Department of Physics, Jiangxi Agricultural University, Nanchang, PR China
| | - Yan Wang
- School of Science, Shandong Jiaotong University, Jinan, PR China
| | - Xiaoyan Xu
- School of Science, Shandong Jiaotong University, Jinan, PR China
| | - Peihua Zhong
- College of Computer Information and Engineering, Jiangxi Agriculture University, Nanchang, PR China
| | - Zhiyong Yang
- Department of Physics, Jiangxi Agricultural University, Nanchang, PR China
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23
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Pal P, Chakraborty S, Jana B. Number of Hydrogen Bonds per Unit Solvent Accessible Surface Area: A Descriptor of Functional States of Proteins. J Phys Chem B 2022; 126:10822-10833. [PMID: 36524238 DOI: 10.1021/acs.jpcb.2c05367] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Proteins function close to native and near-native conformations. These states are evolutionarily selected to ensure the effect of mutations is minimized. The structural organization of a protein is hierarchical and modular, which reduces the dimensionality of the configurational space of the native states. Thus, finding appropriate descriptors that define the native state among all possible states of a protein is a problem of immense interest. The present study explores the correlation between solvent accessible surface areas (SASAs) and different intraprotein as well as protein-water hydrogen bonds of 55 single-chain globular proteins from four different structural classes (all α, all β, α+β, and α/β), 16 multichain proteins, and 4 macromolecular complexes. A systematic analysis of the solvent accessible surface area and intraprotein and protein-water hydrogen bonds suggests a linear relationship between SASAs and hydrogen bonds. The number of protein-water hydrogen bonds per unit SASA ranges from 3 to 4 for all the different structural protein classes. In contrast, the number of intramolecular hydrogen bonds per unit SASA, including the mainchain-mainchain, mainchain-sidechain, and sidechain-sidechain, varies between 0.75 to 2. The solvation free energy of a protein linearly decreases with SASA. Our study also shows that the solvation free energy/SASA varies from -75 to -105 kJ mol-1 nm-2 across all the native states studied here. The number conservancy of intraprotein hydrogen bonds per unit SASA possibly imparts structural stability to the native structure. On the other hand, 3-4 protein-water hydrogen bonds per unit SASA are possibly required to maintain a balance between the solubility and functionality of the native states. This study provides a basis for synthetic biologists to design new folds with improved functionality.
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Affiliation(s)
- Prasun Pal
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Sandipan Chakraborty
- Center for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad 500046, India
| | - Biman Jana
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
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Abstract
Human familial prion diseases are known to be associated with different single-point mutants of the gene coding for prion protein with a primary focus at several locations of the globular domain. We have identified 12 different single-point pathogenic mutants of human prion protein (HuPrP) with the help of extensive perturbations/mutation technique at multiple locations of HuPrP sequence related to potentiality towards conformational disorders. Among these, some of the mutants include pathogenic variants that corroborate well with the literature reported proteins while majority include some unique single-point mutants that are either not explicitly studied early or studied for variants with different residues at the specific position. Primarily, our study sheds light on the unfolding mechanism of the above mentioned mutants in depth. Besides, we could identify some mutants under investigation that demonstrates not only unfolding of the helical structures but also extension and generation of the β-sheet structures and or simultaneously have highly exposed hydrophobic surface which is assumed to be linked with the production of aggregate/fibril structures of the prion protein. Among the identified mutants, Q212E needs special attention due to its maximum exposure of hydrophobic core towards solvent and E200Q is found to be important due to its maximum extent of β-content. We are also able to identify different respective structural conformations of the proteins according to their degree of structural unfolding and those conformations can be extracted and further studied in detail. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Puspita Halder
- Department of Computer Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, India
| | - Pralay Mitra
- Department of Computer Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, India
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Paul SK, Saddam M, Rahaman KA, Choi J, Lee S, Hasan M. Molecular modeling, molecular dynamics simulation, and essential dynamics analysis of grancalcin: An upregulated biomarker in experimental autoimmune encephalomyelitis mice. Heliyon 2022; 8:e11232. [PMID: 36340004 PMCID: PMC9626934 DOI: 10.1016/j.heliyon.2022.e11232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 05/30/2022] [Accepted: 10/20/2022] [Indexed: 11/06/2022] Open
Abstract
The experimental autoimmune encephalomyelitis mouse model is the most commonly used animal model, and it best represents multiple sclerosis. Grancalcin (GCA) was discovered to be upregulated in EAE mice. GCA comprises 220 amino acids that have been assigned the UniprotKB ID Q8VC88. It is a calcium-binding protein that helps neutrophils adhere to fibronectin and the formation of focal adhesions. However, the protein data bank does not contain the crystal structure of mouse GCA. The current study aims to analyze the structural and physicochemical properties of GCA. Mouse GCA showed a high percentage identity (87%) with the crystal structure of des (1–52) grancalcin with bound calcium (chain A) from Homo sapiens identified by its PDB id 1k94_A. Using the SWISS-MODEL server, we used 1k94_A as a template protein to model the mouse GCA protein. Compared to the template structure 1K94, three potential binding sites for calcium-binding have been proposed, ranging from 13 to 20, 80 to 91, and 109 to 120 amino acids. On an i5 personal computer with 8GB of RAM, GROMACS 2020.1 was utilized to run a 100 ns molecular dynamics (MD) simulation. RMSD, Rg, and RMSF analysis of an MD simulation trajectory indicate a stable and compact state throughout the simulation period of modeled proteins. We found that GCA is primarily alpha helical (Class 1), with eight alpha helices. The essential dynamics analysis captures PCA and SASA, culminating in the biological motions that correspond to the last 1000 frames. These findings will aid the development of potential inhibitors as well as the determination of binding pockets and residues for drug-like molecules.
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Yu YX, Wang W, Sun HB, Zhang LL, Wang LF, Yin YY. Decoding drug resistant mechanism of V32I, I50V and I84V mutations of HIV-1 protease on amprenavir binding by using molecular dynamics simulations and MM-GBSA calculations. SAR QSAR Environ Res 2022; 33:805-831. [PMID: 36322686 DOI: 10.1080/1062936x.2022.2140708] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 10/20/2022] [Indexed: 06/16/2023]
Abstract
Mutations V32I, I50V and I84V in the HIV-1 protease (PR) induce drug resistance towards drug amprenavir (APV). Multiple short molecular dynamics (MSMD) simulations and molecular mechanics generalized Born surface area (MM-GBSA) method were utilized to investigate drug-resistant mechanism of V32I, I50V and I84V towards APV. Dynamic information arising from MSMD simulations suggest that V32I, I50V and I84V highly affect structural flexibility, motion modes and conformational behaviours of two flaps in the PR. Binding free energies calculated by MM-GBSA method suggest that the decrease in binding enthalpy and the increase in binding entropy induced by mutations V32I, I50V and I84V are responsible for drug resistance of the mutated PRs on APV. The energetic contributions of separate residues on binding of APV to the PR show that V32I, I50V and I84V highly disturb the interactions of two flaps with APV and mostly drive the decrease in binding ability of APV to the PR. Thus, the conformational changes of two flaps in the PR caused by V32I, I50V and I84V play key roles in drug resistance of three mutated PR towards APV. This study can provide useful dynamics information for the design of potent inhibitors relieving drug resistance.
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Affiliation(s)
- Y X Yu
- School of Science, Shandong Jiaotong University, Jinan, China
| | - W Wang
- School of Science, Shandong Jiaotong University, Jinan, China
| | - H B Sun
- School of Science, Shandong Jiaotong University, Jinan, China
| | - L L Zhang
- School of Science, Shandong Jiaotong University, Jinan, China
| | - L F Wang
- School of Science, Shandong Jiaotong University, Jinan, China
| | - Y Y Yin
- School of Science, Shandong Jiaotong University, Jinan, China
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Yagasaki T, Matubayasi N. Molecular dynamics study of the interactions between a hydrophilic polymer brush on graphene and amino acid side chain analogues in water. Phys Chem Chem Phys 2022; 24:22877-22888. [PMID: 36124732 DOI: 10.1039/d2cp03112d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We perform all-atom molecular dynamics simulations of poly(2-hydroxyethyl methacrylate) (PHEMA) brushes in aqueous solutions of isobutane, propionamide, and sodium propionate. These solutes are side chain analogues to leucine, glutamine, and glutamic acid, respectively. We compute the Gibbs energy profile of the solute's adsorption to the polymer brush and decompose it into the contributions from the steric repulsion, van der Waals interaction, and Coulomb interaction to reveal the energetic origin of repulsion or attraction of the solute by the polymer brush. The Henry adsorption constant is the amount of adsorption normalized by the concentration in aqueous solution. We examine the dependence of this quantity on the grafting density and chain length. Our results suggest that the concurrent primary and ternary adsorption mechanism may be more important than previously expected when the solute is hydrophobic.
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Affiliation(s)
- Takuma Yagasaki
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan.
| | - Nobuyuki Matubayasi
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan.
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Matsubara D, Kasahara K, Dokainish HM, Oshima H, Sugita Y. Modified Protein-Water Interactions in CHARMM36m for Thermodynamics and Kinetics of Proteins in Dilute and Crowded Solutions. Molecules 2022; 27:molecules27175726. [PMID: 36080494 PMCID: PMC9457699 DOI: 10.3390/molecules27175726] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/30/2022] [Accepted: 08/30/2022] [Indexed: 11/16/2022] Open
Abstract
Proper balance between protein-protein and protein-water interactions is vital for atomistic molecular dynamics (MD) simulations of globular proteins as well as intrinsically disordered proteins (IDPs). The overestimation of protein-protein interactions tends to make IDPs more compact than those in experiments. Likewise, multiple proteins in crowded solutions are aggregated with each other too strongly. To optimize the balance, Lennard-Jones (LJ) interactions between protein and water are often increased about 10% (with a scaling parameter, λ = 1.1) from the existing force fields. Here, we explore the optimal scaling parameter of protein-water LJ interactions for CHARMM36m in conjunction with the modified TIP3P water model, by performing enhanced sampling MD simulations of several peptides in dilute solutions and conventional MD simulations of globular proteins in dilute and crowded solutions. In our simulations, 10% increase of protein-water LJ interaction for the CHARMM36m cannot maintain stability of a small helical peptide, (AAQAA)3 in a dilute solution and only a small modification of protein-water LJ interaction up to the 3% increase (λ = 1.03) is allowed. The modified protein-water interactions are applicable to other peptides and globular proteins in dilute solutions without changing thermodynamic properties from the original CHARMM36m. However, it has a great impact on the diffusive properties of proteins in crowded solutions, avoiding the formation of too sticky protein-protein interactions.
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Affiliation(s)
- Daiki Matsubara
- Laboratory for Biomolecular Function Simulation, RIKEN Center for Biosystems Dynamics Research, Kobe 650-0047, Hyogo, Japan
| | - Kento Kasahara
- Laboratory for Biomolecular Function Simulation, RIKEN Center for Biosystems Dynamics Research, Kobe 650-0047, Hyogo, Japan
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Osaka, Japan
| | - Hisham M. Dokainish
- Theoretical Molecular Science Laboratory, RIKEN Cluster for Pioneering Research, Wako 351-0198, Saitama, Japan
| | - Hiraku Oshima
- Laboratory for Biomolecular Function Simulation, RIKEN Center for Biosystems Dynamics Research, Kobe 650-0047, Hyogo, Japan
| | - Yuji Sugita
- Laboratory for Biomolecular Function Simulation, RIKEN Center for Biosystems Dynamics Research, Kobe 650-0047, Hyogo, Japan
- Theoretical Molecular Science Laboratory, RIKEN Cluster for Pioneering Research, Wako 351-0198, Saitama, Japan
- Computational Biophysics Research Team, RIKEN Center for Computational Science, Kobe 650-0047, Hyogo, Japan
- Correspondence: ; Tel.: +81-48-462-1407
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Chang M, Liu X, Lin Q, Li W, Wang X, Ren J. A highly stretchable, UV resistant and underwater adhesive hydrogel based on xylan derivative for sensing. Int J Biol Macromol 2022; 220:1084-94. [PMID: 35985397 DOI: 10.1016/j.ijbiomac.2022.08.077] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 07/31/2022] [Accepted: 08/11/2022] [Indexed: 11/22/2022]
Abstract
Hydrogels with fascinating adhesion have been demonstrated great potential in various applications. However, most hydrogels lose their adhesion in wet or underwater environments due to the influence of interfacial water. Inspired by mussel, an underwater adhesive hydrogel was facilely fabricated by introducing electrostatic interactions, which consisted of poly (acrylic acid) (PAA), quaternized xylan (QAX) and tannic acid (TA). In this hydrogel, -COO- from PAA, -N+(CH3)3 from QAX and catechol group from TA resembled amino acids with negative and positive charges and 3,4-dihydroxyphenylalanine units in mussel, which endowed the hydrogels with great underwater adhesion through multiple interactions. Notably, acrylic acid (AA) played a key role in the dispersion of the system. QAX, a biomass derived from plants with excellent properties, worked with PAA to construct hydrogel networks. The resultant hydrogels exhibited excellent mechanical properties including remarkable stretchability (>4000 %) and compressibility. Moreover, the hydrogels had superior UV-blocking (~99.96 %), and showed good adhesion both in air and underwater. The hydrogels can be exploited as a wearable sensor to monitor human motions and even subtle motions, which have the potential to be explored in human health monitoring.
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Oshima H, Sugita Y. Modified Hamiltonian in FEP Calculations for Reducing the Computational Cost of Electrostatic Interactions. J Chem Inf Model 2022; 62:2846-2856. [PMID: 35639709 DOI: 10.1021/acs.jcim.1c01532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The free-energy perturbation (FEP) method predicts relative and absolute free-energy changes of biomolecules in solvation and binding with other molecules. FEP is, therefore, one of the most essential tools in in silico drug design. In conventional FEP, to smoothly connect two thermodynamic states, the potential energy is modified as a linear combination of the end-state potential energies by introducing scaling factors. When the particle mesh Ewald is used for electrostatic calculations, conventional FEP requires two reciprocal-space calculations per time step, which largely decreases the computational performance. To overcome this problem, we propose a new FEP scheme by introducing a modified Hamiltonian instead of interpolation of the end-state potential energies. The scheme introduces nonuniform scaling into the electrostatic potential as used in Replica Exchange with Solute Tempering 2 (REST2) and does not require additional reciprocal-space calculations. We tested this modified Hamiltonian in FEP calculations in several biomolecular systems. In all cases, the calculated free-energy changes with the current scheme are in good agreement with those from conventional FEP. The modified Hamiltonian in FEP greatly improves the computational performance, which is particularly marked for large biomolecular systems whose reciprocal-space calculations are the major bottleneck of total computational time.
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Affiliation(s)
- Hiraku Oshima
- Laboratory for Biomolecular Function Simulation, RIKEN Center for Biosystems Dynamics Research, Integrated Innovation Building 7F, 6-7-1 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Yuji Sugita
- Laboratory for Biomolecular Function Simulation, RIKEN Center for Biosystems Dynamics Research, Integrated Innovation Building 7F, 6-7-1 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.,Theoretical Molecular Science Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.,Computational Biophysics Research Team, RIKEN Center for Computational Science, Integrated Innovation Building 7F, 6-7-1 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
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Yasoshima N, Ishiyama T, Matubayasi N. Adsorption Energetics of Amino Acid Analogs on Polymer/Water Interfaces Studied by All-Atom Molecular Dynamics Simulation and a Theory of Solutions. J Phys Chem B 2022; 126:4389-4400. [PMID: 35653506 DOI: 10.1021/acs.jpcb.2c01297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Energetics of adsorption was addressed with all-atom molecular dynamics simulation on the interfaces of poly(2-methoxyethyl acrylate) (PMEA), poly(methyl methacrylate) (PMMA), and poly(butyl acrylate) (PBA) with water. A wide variety of adsorbate solutes were examined, and the free energy of adsorption was computed with the method of energy representation. It was found that the adsorption free energy was favorable (negative) for all the combinations of solute and polymer, and among PMEA, PMMA, and PBA, the strongest adsorption was observed on PMMA for the hydrophobic solutes and on PMEA for the hydrophilic ones. According to the decomposition of the adsorption free energy into the contributions from polymer and water, it was seen that the polymer contribution is larger in magnitude with the solute size. The total free energy of adsorption was correlated well with the solvation free energy in bulk water only for hydrophobic solutes. The roles of the intermolecular interaction components such as electrostatic, van der Waals, and excluded-volume were further studied, and the electrostatic component was influential only in determining the polymer dependences of the adsorption propensities of hydrophilic solutes. The extent of adsorption was shown to be ranked by the van der Waals component in the solute-polymer interaction separately over the hydrophilic and hydrophobic solutes, with the excluded-volume effect from water pointed out to also drive the adsorption.
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Affiliation(s)
- Nobuhiro Yasoshima
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Tatsuya Ishiyama
- Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan
| | - Nobuyuki Matubayasi
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
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32
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Galamba N. Aggregation of a Parkinson's Disease-Related Peptide: When Does Urea Weaken Hydrophobic Interactions? ACS Chem Neurosci 2022; 13:1769-1781. [PMID: 35616516 PMCID: PMC9775218 DOI: 10.1021/acschemneuro.2c00169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
While the exact cause of neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease is not completely understood, compelling evidence implicates the aggregation of specific proteins and peptides. Co-solvents can provide molecular insight into protein aggregation mechanisms and the chemical nature of potential aggregation inhibitors. Here, we study, through molecular simulations, the hydration and binding free energies of an amphiphilic peptide from the nonamyloid-β component (NAC), a key aggregation-prone domain of α-synuclein, in water and an 8 M aqueous urea solution. Isoleucine, glycine, and serine peptides of the same length are also studied to unravel the role of urea in the hydration and aggregation of hydrophobic and hydrophilic domains. A strong impact of urea in hindering the aggregation of the NAC subdomain is observed. A slightly weaker aggregation inhibition is observed for the Gly and Ser peptides, whereas a much lower aggregation inhibitory activity is found for the Ile peptide, seemingly contrasting with urea's protein unfolding mechanism. This behavior is shown to derive from a lower profusion of urea next to the hydrophobic side chains and the backbone of the Ile's peptide in the dimeric form. As a consequence, β-sheets, formed upon aggregation, remain nearly intact. Hydrophilic neighbor groups in the amphiphilic NAC subdomain, however, are shown to anchor enough urea to weaken hydrophobic interactions and disrupt β-sheet structures. Our results indicate that urea's activity is potentiated in amphiphilic domains and that potential drugs could disrupt hydrophobic β-sheet-rich regions while not binding primarily to hydrophobic amino acids.
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Quiroz-Hernández B, Castillo-Tejas J, Manero O. Free energy calculations in associative polymers using molecular dynamics. Molecular Simulation 2022. [DOI: 10.1080/08927022.2022.2063283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- B. Quiroz-Hernández
- Facultad de Ciencias Básicas, Ingeniería y Tecnología, Universidad Autónoma de Tlaxcala, Apizaco, Mexico
| | - J. Castillo-Tejas
- Facultad de Ciencias Básicas, Ingeniería y Tecnología, Universidad Autónoma de Tlaxcala, Apizaco, Mexico
| | - O. Manero
- Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Mexico
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34
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Barbosa GD, Bara JE, Weinman ST, Turner CH. Molecular aspects of temperature swing solvent extraction for brine desalination using imidazole-based solvents. Chem Eng Sci 2022. [DOI: 10.1016/j.ces.2021.116866] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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35
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Caceres-Delpiano J, Wang LP, Essex JW. The automated optimisation of a coarse-grained force field using free energy data. Phys Chem Chem Phys 2021; 23:24842-24851. [PMID: 34723311 PMCID: PMC8579472 DOI: 10.1039/d0cp05041e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 10/18/2021] [Indexed: 11/21/2022]
Abstract
Atomistic models provide a detailed representation of molecular systems, but are sometimes inadequate for simulations of large systems over long timescales. Coarse-grained models enable accelerated simulations by reducing the number of degrees of freedom, at the cost of reduced accuracy. New optimisation processes to parameterise these models could improve their quality and range of applicability. We present an automated approach for the optimisation of coarse-grained force fields, by reproducing free energy data derived from atomistic molecular simulations. To illustrate the approach, we implemented hydration free energy gradients as a new target for force field optimisation in ForceBalance and applied it successfully to optimise the un-charged side-chains and the protein backbone in the SIRAH protein coarse-grain force field. The optimised parameters closely reproduced hydration free energies of atomistic models and gave improved agreement with experiment.
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Affiliation(s)
| | - Lee-Ping Wang
- Department of Chemistry, University of California, Davis, California 95616, USA.
| | - Jonathan W Essex
- School of Chemistry, University of Southampton, Southapton, S017 1BJ, UK.
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36
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Li M, Cong Y, Qi Y, Zhang JZH. Computational Insights into the Binding Mechanism of OxyS sRNA with Chaperone Protein Hfq. Biomolecules 2021; 11:biom11111653. [PMID: 34827651 PMCID: PMC8615722 DOI: 10.3390/biom11111653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 10/16/2021] [Accepted: 10/27/2021] [Indexed: 11/16/2022] Open
Abstract
Under the oxidative stress condition, the small RNA (sRNA) OxyS that acts as essential post-transcriptional regulators of gene expression is produced and plays a regulatory function with the assistance of the RNA chaperone Hfq protein. Interestingly, experimental studies found that the N48A mutation of Hfq protein could enhance the binding affinity with OxyS while resulting in the defection of gene regulation. However, how the Hfq protein interacts with sRNA OxyS and the origin of the stronger affinity of N48A mutation are both unclear. In this paper, molecular dynamics (MD) simulations were performed on the complex structure of Hfq and OxyS to explore their binding mechanism. The molecular mechanics generalized born surface area (MM/GBSA) and interaction entropy (IE) method were combined to calculate the binding free energy between Hfq and OxyS sRNA, and the computational result was correlated with the experimental result. Per-residue decomposition of the binding free energy revealed that the enhanced binding ability of the N48A mutation mainly came from the increased van der Waals interactions (vdW). This research explored the binding mechanism between Oxys and chaperone protein Hfq and revealed the origin of the strong binding affinity of N48A mutation. The results provided important insights into the mechanism of gene expression regulation affected by protein mutations.
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Affiliation(s)
- Mengxin Li
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, Shanghai Key Laboratory of Green Chemistry & Chemical Process, School of Chemistry and Molecular Engineering, East China Normal University at Shanghai, Shanghai 200062, China; (M.L.); (Y.C.); (Y.Q.)
| | - Yalong Cong
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, Shanghai Key Laboratory of Green Chemistry & Chemical Process, School of Chemistry and Molecular Engineering, East China Normal University at Shanghai, Shanghai 200062, China; (M.L.); (Y.C.); (Y.Q.)
| | - Yifei Qi
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, Shanghai Key Laboratory of Green Chemistry & Chemical Process, School of Chemistry and Molecular Engineering, East China Normal University at Shanghai, Shanghai 200062, China; (M.L.); (Y.C.); (Y.Q.)
- Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518000, China
| | - John Z. H. Zhang
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, Shanghai Key Laboratory of Green Chemistry & Chemical Process, School of Chemistry and Molecular Engineering, East China Normal University at Shanghai, Shanghai 200062, China; (M.L.); (Y.C.); (Y.Q.)
- Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518000, China
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai 200062, China
- Department of Chemistry, New York University, New York, NY 10003, USA
- Correspondence:
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Yu YX, Liu WT, Li HY, Wang W, Sun HB, Zhang LL, Wu SL. Decoding molecular mechanism underlying binding of drugs to HIV-1 protease with molecular dynamics simulations and MM-GBSA calculations. SAR QSAR Environ Res 2021; 32:889-915. [PMID: 34551634 DOI: 10.1080/1062936x.2021.1979647] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 09/08/2021] [Indexed: 06/13/2023]
Abstract
HIV-1 protease (PR) is thought to be efficient targets of anti-AIDS drug design. Molecular dynamics (MD) simulations and multiple post-processing analysis technologies were applied to decipher molecular mechanism underlying binding of three drugs Lopinavir (LPV), Nelfinavir (NFV) and Atazanavir (ATV) to the PR. Binding free energies calculated by molecular mechanics generalized Born surface area (MM-GBSA) suggest that compensation between binding enthalpy and entropy plays a vital role in binding of drugs to PR. Dynamics analyses show that binding of LPV, NFV and ATV highly affects structural flexibility, motion modes and dynamics behaviour of the PR, especially for two flaps. Computational alanine scanning and interaction network analysis verify that although three drugs have structural difference, they share similar binding modes to the PR and common interaction clusters with the PR. The current findings also confirm that residues located interaction clusters, such as Asp25/Asp25', Gly27/Gly27', Ala28/Ala28', Asp29, Ile47/Ile47', Gly49/Gly49', Ile50/Ile50', Val82/Val82' and Ile84/Ile84, can be used as efficient targets of clinically available inhibitors towards the PR.
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Affiliation(s)
- Y X Yu
- School of Science, Shandong Jiaotong University, Jinan, China
| | - W T Liu
- Shuifa Qilu Cultural Tourism Development Co., Ltd, Shuifa Ecological Industry Group, Jinan, China
| | - H Y Li
- School of Science, Shandong Jiaotong University, Jinan, China
| | - W Wang
- School of Science, Shandong Jiaotong University, Jinan, China
| | - H B Sun
- School of Science, Shandong Jiaotong University, Jinan, China
| | - L L Zhang
- School of Science, Shandong Jiaotong University, Jinan, China
| | - S L Wu
- School of Science, Shandong Jiaotong University, Jinan, China
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Barbosa GD, Liu X, Bara JE, Weinman ST, Turner CH. High-salinity brine desalination with amine-based temperature swing solvent extraction: A molecular dynamics study. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.117359] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Abstract
Molecular self-assembly is a ubiquitous phenomenon in which individual atoms or molecules set up an ordered structure. It is of high interest for understanding the biology and a variety of diseases at the molecular level. In this work, we studied the self-assembly of tyrosine molecules via extensive molecular dynamics simulations. The formation of structures by self-assembly was systematically studied at various concentrations, from very low to very high. The temperature was kept constant, at which, in our former studies, we have already observed well-formed self-assembled structures. Depending on the concentration, the system displays a wide range of different structures, ranging from freely scattered monomers to very well formed four-fold structures. Different regimes of concentration dependence are observed. The results are proved by calculating the moments of inertia of the structures and the number of hydrogen bonds formed. Free energy landscapes calculated for the number of hydrogen bonds versus the number of contacts within a criterion provide insights into the structures observed.
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Affiliation(s)
- Hajar Nili Ahmadabadi
- Department of Physics, Faculty of Physics and Chemistry, Alzahra University, Tehran, Iran.
| | - Amir Ali Masoudi
- Department of Physics, Faculty of Physics and Chemistry, Alzahra University, Tehran, Iran.
| | - Sahin Uyaver
- Department of Energy Science and Technologies, Turkish-German University, Sahinkaya Cad 106 34820 Beykoz, Istanbul, Turkey.
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Wang L, O'Mara ML. Effect of the Force Field on Molecular Dynamics Simulations of the Multidrug Efflux Protein P-Glycoprotein. J Chem Theory Comput 2021; 17:6491-6508. [PMID: 34506133 DOI: 10.1021/acs.jctc.1c00414] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Molecular dynamics (MD) simulations have been used extensively to study P-glycoprotein (P-gp), a flexible multidrug transporter that is a key player in the development of multidrug resistance to chemotherapeutics. A substantial body of literature has grown from simulation studies that have employed various simulation conditions and parameters, including AMBER, CHARMM, OPLS, GROMOS, and coarse-grained force fields, drawing conclusions from simulations spanning hundreds of nanoseconds. Each force field is typically parametrized and validated on different data and observables, usually of small molecules and peptides; there have been few comparisons of force field performance on large protein-membrane systems. Here we compare the conformational ensembles of P-gp embedded in a POPC/cholesterol bilayer generated over 500 ns of replicate simulation with five force fields from popular biomolecular families: AMBER 99SB-ILDN, CHARMM 36, OPLS-AA/L, GROMOS 54A7, and MARTINI. We find considerable differences among the ensembles with little conformational overlap, although they correspond to similar extents to structural data obtained from electron paramagnetic resonance and cross-linking studies. Moreover, each trajectory was still sampling new conformations at a high rate after 500 ns of simulation, suggesting the need for more sampling. This work highlights the need to consider known limitations of the force field used (e.g., biases toward certain secondary structures) and the simulation itself (e.g., whether sufficient sampling has been achieved) when interpreting accumulated results of simulation studies of P-gp and other transport proteins.
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Affiliation(s)
- Lily Wang
- Research School of Chemistry, College of Science, Australian National University, Canberra, ACT 2601, Australia
| | - Megan L O'Mara
- Research School of Chemistry, College of Science, Australian National University, Canberra, ACT 2601, Australia
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41
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Iscen A, Forero-Martinez NC, Valsson O, Kremer K. Acrylic Paints: An Atomistic View of Polymer Structure and Effects of Environmental Pollutants. J Phys Chem B 2021; 125:10854-10865. [PMID: 34524824 PMCID: PMC8488938 DOI: 10.1021/acs.jpcb.1c05188] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Most of the artwork
and cultural heritage objects are stored in
museums under conditions that are difficult to monitor. While advanced
technologies aim to control and prevent the degradation of cultural
heritage objects in line with preventive conservation measures, there
is much to be learned in terms of the physical processes that lead
to the degradation of the synthetic polymers that form the basis of
acrylic paints largely used in contemporary art. In museums, stored
objects are often exposed to temperature and relative humidity fluctuations
as well as airborne pollutants such as volatile organic compounds
(VOCs). The glass transition of acrylic paints is below room temperature;
while low temperatures may cause cracking, at high temperatures the
sticky surface of the paint becomes vulnerable to pollutants. Here
we develop fully atomistic models to understand the structure of two
types of acrylic copolymers and their interactions with VOCs and water.
The structure and properties of acrylic copolymers are slighlty modified
by incorporation of a monomer with a longer side chain. With favorable
solvation free energies, once absorbed, VOCs and water interact with
the polymer side chains to form hydrogen bonds. The cagelike structure
of the polymers prevents the VOCs and water to diffuse freely below
the glass transition temperature. In addition, our model forms the
foundation for developing mesoscopic and continuum models that will
allow us to access longer time and length scales to further our understanding
of the degradation of artwork.
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Affiliation(s)
- Aysenur Iscen
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | | | - Omar Valsson
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Kurt Kremer
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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42
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Zhang Y, Jiang Y, Qiu Y, Zhang H. Rational Design of Nonbonded Point Charge Models for Highly Charged Metal Cations with Lennard-Jones 12-6 Potential. J Chem Inf Model 2021; 61:4613-4629. [PMID: 34467756 DOI: 10.1021/acs.jcim.1c00723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Here, we developed nonbonded point charge models using a simple Lennard-Jones (LJ) 12-6 potential for highly charged metal cations (18 trivalent and 6 tetravalent ions) for use with 11 water models of TIP3P, OPC3, SPC/E, SPC/Eb, TIP3P-FB, a99SB-disp, TIP4P-Ew, OPC, TIP4P/2005, TIP4P-D, and TIP4P-FB. The designed models simultaneously reproduce the hydration free energy (HFE) and ion-oxygen distance (IOD) in the first hydration shell with an error within 1 kcal/mol and 0.01 Å on average, respectively, and yield reasonable coordination numbers for most cations. Such performance is equivalent to the previously reported point charge models using a more complex 12-6-4 LJ-type potential, while the LJ R parameters of our models are much close to Shannon's revised effective ion radii than that of the 12-6-4 models. Our designed models overestimate the diffusion constants of several trivalent ions by 5-68%. The performance in predicting osmotic coefficients of trivalent chlorides in aqueous solution depends on the salt type. A calibration of cation-anion interacting LJ parameters reproduces the experimental osmotic coefficients of an AlCl3 solution at 0.2-3.0 mol/L. The effectiveness of our new models is further demonstrated by simulating a metalloprotein system with four force field/water combinations. This work facilitates accurate modeling of metal-containing systems by a variety of force fields and water models in aqueous solution.
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Affiliation(s)
- Yongguang Zhang
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083 Beijing, China
| | - Yang Jiang
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Yejie Qiu
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083 Beijing, China
| | - Haiyang Zhang
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083 Beijing, China
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43
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Kode VR, Hinkle KR, Ao G. Interaction of DNA-Complexed Boron Nitride Nanotubes and Cosolvents Impacts Dispersion and Length Characteristics. Langmuir 2021; 37:10934-10944. [PMID: 34496213 DOI: 10.1021/acs.langmuir.1c01309] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Processing boron nitride nanotubes (BNNTs) for applications ranging from nanomedicine to electronics generally requires dispersions of nanotubes that are stable in various compounds and solvents. We show that alcohol/water cosolvents, particularly isopropyl alcohol (IPA), are essential for the complexation of BNNTs with DNA under mild bath sonication. The resulting DNA-wrapped BNNT complexes are highly stable during purification and solvent exchange from cosolvents to water, providing potential for the versatile liquid-phase processing of BNNTs. Via molecular dynamics simulations, we demonstrate that IPA assists in the solvation of BNNTs due to its pseudosurfactant nature by verifying that water is replaced in the solvation layer as IPA is added. We quantify the solvation free energy of BNNTs in various IPA/water mixtures and observe a nonmonotonic trend, highlighting the importance of utilizing solvent-nanotube interactions in nanomaterial dispersions. Additionally, we show that nanotube lengths can be characterized by rheology measurements via determining the viscosity of dilute dispersions of DNA-BNNTs. This represents the bulk sample property in the liquid state, as compared to conventional imaging techniques that require surface deposition and drying. Our results also demonstrate that BNNT dispersions exhibit the rheological behavior of dilute Brownian rigid rods, which can be further exploited for the controlled processing and property enhancement of BNNT-enabled assemblies such as films and fibers.
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Affiliation(s)
- Venkateswara R Kode
- Department of Chemical and Biomedical Engineering, Washkewicz College of Engineering, Cleveland State University, 2121 Euclid Avenue, Cleveland, Ohio 44115, United States
| | - Kevin R Hinkle
- Department of Chemical and Materials Engineering, University of Dayton, 300 College Park, Dayton, Ohio 45469, United States
| | - Geyou Ao
- Department of Chemical and Biomedical Engineering, Washkewicz College of Engineering, Cleveland State University, 2121 Euclid Avenue, Cleveland, Ohio 44115, United States
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Kele Y, Yuemeng R, Cheng L, Anshan X, Xiaofang L. Methane hydrate formation behaviors in high water-cut oil-in-water systems with hydrate promoters. RSC Adv 2021; 11:30597-30609. [PMID: 35479858 PMCID: PMC9041106 DOI: 10.1039/d1ra03501k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 08/27/2021] [Indexed: 11/21/2022] Open
Abstract
Hydrate slurry transport technology has become a focal point among worldwide researches, due to its high economic efficiency. However, the mechanism and law of hydrate growth kinetics in flow systems were still unclear, especially in high water-cut oil-water systems with hydrate promoters. On this basis, this paper conducted a series of growth kinetic experiments using a high-pressure transparent sapphire cell, and investigated systematically several influencing factors (such as initial pressure, the concentration of emulsifier, hydrate promoter, and the concentration of hydrate promoter) of growth kinetics, and obtained the quantitative relationship between these factors and gas consumption as well as the hydrate growth rate (gas consumption rate). It could be seen from the analysis of these influencing factors that the presence of hydrate promoters can promote hydrate nucleation rapidly and shorten the hydrate induction time, as compared with the (diesel oil + water) system. The concentration of emulsifier is positively correlated with the induction period of hydrate formation, whether it was sodium dodecyl sulfate (SDS) or l-leucine (l-l) systems. The SDS and l-l system could significantly improve the formation kinetics of methane hydrate in the emulsion system, while tetrabutylammonium bromide (TBAB) and polysorbate 80 (Tween80) significantly inhibited the nucleation and growth of methane hydrate in the emulsion. The kinetic curves of hydrate formation showed a trend of first increasing and then gradually decreasing, with the increase of SDS concentrations. However, the hydrate formation kinetics tended to increase gradually and reach equilibrium in the l-l system, with an increase in the concentration of l-l.
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Affiliation(s)
- Yan Kele
- SINOPEC Qingdao Research Institute of Safety Engineering Qingdao China +86-532-83786440.,State Key Laboratory of Safety and Control for Chemicals Qingdao China
| | - Ren Yuemeng
- SINOPEC Qingdao Research Institute of Safety Engineering Qingdao China +86-532-83786440.,State Key Laboratory of Safety and Control for Chemicals Qingdao China
| | - Lv Cheng
- SINOPEC Qingdao Research Institute of Safety Engineering Qingdao China +86-532-83786440.,State Key Laboratory of Safety and Control for Chemicals Qingdao China
| | - Xiao Anshan
- SINOPEC Qingdao Research Institute of Safety Engineering Qingdao China +86-532-83786440.,State Key Laboratory of Safety and Control for Chemicals Qingdao China
| | - Lv Xiaofang
- Jiangsu Key Laboratory of Oil and Gas Storage & Transportation Technology, School of Petroleum Engineering, Changzhou University Changzhou China
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45
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Sabatino SJ, Paluch AS. Predicting octanol/water partition coefficients using molecular simulation for the SAMPL7 challenge: comparing the use of neat and water saturated 1-octanol. J Comput Aided Mol Des 2021; 35:1009-1024. [PMID: 34495430 DOI: 10.1007/s10822-021-00415-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 08/09/2021] [Indexed: 11/29/2022]
Abstract
Blind predictions of octanol/water partition coefficients at 298.15 K for 22 drug-like compounds were made for the SAMPL7 challenge. The octanol/water partition coefficients were predicted using solvation free energies computed using molecular dynamics simulations, wherein we considered the use of both pure and water-saturated 1-octanol to model the octanol-rich phase. Water and 1-octanol were modeled using TIP4P and TrAPPE-UA, respectively, which have been shown to well reproduce the experimental mutual solubility, and the solutes were modeled using GAFF. After the close of the SAMPL7 challenge, we additionally made predictions using TIP4P/2005 water. We found that the predictions were sensitive to the choice of water force field. However, the effect of water in the octanol-rich phase was found to be even more significant and non-negligible. The effect of inclusion of water was additionally sensitive to the chemical structure of the solute.
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Affiliation(s)
- Spencer J Sabatino
- Department of Chemical, Paper, and Biomedical Engineering, Miami University, Oxford, OH, 45056, USA
| | - Andrew S Paluch
- Department of Chemical, Paper, and Biomedical Engineering, Miami University, Oxford, OH, 45056, USA.
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46
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Azadpour M, Jayhani Z, Pourmand S, Mohebbi A. Molecular dynamic insight into solubility of H2S in ionic liquids [emim][BF4], [emim][OTf] and [emim][Tf2N]. J Mol Liq 2021; 338:117114. [DOI: 10.1016/j.molliq.2021.117114] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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47
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Gotzias A, Tocci E, Sapalidis A. On the Consistency of the Exfoliation Free Energy of Graphenes by Molecular Simulations. Int J Mol Sci 2021; 22:ijms22158291. [PMID: 34361058 PMCID: PMC8347420 DOI: 10.3390/ijms22158291] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 01/04/2023] Open
Abstract
Monolayer graphene is now produced at significant yields, by liquid phase exfoliation of graphites in solvents. This has increased the interest in molecular simulation studies to give new insights in the field. We use decoupling simulations to compute the exfoliation free energy of graphenes in a liquid environment. Starting from a bilayer graphene configuration, we decouple the Van der Waals interactions of a graphene monolayer in the presence of saline water. Then, we introduce the monolayer back into water by coupling its interactions with water molecules and ions. A different approach to compute the graphene exfoliation free energy is to use umbrella sampling. We apply umbrella sampling after pulling the graphene monolayer on the shear direction up to a distance from a bilayer. We show that the decoupling and umbrella methods give highly consistent free energy results for three bilayer graphene samples with different size. This strongly suggests that the systems in both methods remain closely in equilibrium as we move between the states before and after the exfoliation. Therefore, the amount of nonequilibrium work needed to peel the two layers apart is minimized efficiently.
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Affiliation(s)
- Anastasios Gotzias
- National Centre for Scientific Research “Demokritos”, Institute of Nanoscience and Nanotechnology INN, 15310 Athens, Greece;
- Correspondence: ; Tel.: +30-210-6503408
| | - Elena Tocci
- Institute on Membrane Technology ITM–CNR, National Research Council, 87036 Rende, Italy;
| | - Andreas Sapalidis
- National Centre for Scientific Research “Demokritos”, Institute of Nanoscience and Nanotechnology INN, 15310 Athens, Greece;
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48
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Xiao T, Zhou Y. Fast Calculation of Electrostatic Solvation Free Energy in Simple Ionic Fluids Using an Energy-Scaled Debye-Hückel Theory. J Phys Chem Lett 2021; 12:6262-6268. [PMID: 34197123 DOI: 10.1021/acs.jpclett.1c01643] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Continuum theories are useful to compute the solvation free energy in ionic fluids. Herein, the electrostatic solvation free energy (ESFE) in simple ionic fluids is studied with an energy-scaled Debye-Hückel (ESDH) theory. Given the ESFEs of simple spherical ions as input, the ESDH theory is applicable to molecules with various complex geometries and charge distributions. Specifically, the ESDH theory is applied to molecules in a molten salt system, where the predicted ESFEs are in good agreement with molecular dynamics simulation results. Our study sheds light on accurately predicting the ESFE in ionic fluids with phenomenological continuum theories.
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Affiliation(s)
- Tiejun Xiao
- Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Synergetic Innovation Center of Scientific Big Data for Advanced Manufacturing Technology, Guizhou Education University, Guiyang 550018, People's Republic of China
| | - Yun Zhou
- Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Synergetic Innovation Center of Scientific Big Data for Advanced Manufacturing Technology, Guizhou Education University, Guiyang 550018, People's Republic of China
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49
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Imoro N, Shilovskikh VV, Nesterov PV, Timralieva AA, Gets D, Nebalueva A, Lavrentev FV, Novikov AS, Kondratyuk ND, Orekhov ND, Skorb EV. Biocompatible pH-Degradable Functional Capsules Based on Melamine Cyanurate Self-Assembly. ACS Omega 2021; 6:17267-17275. [PMID: 34278113 PMCID: PMC8280711 DOI: 10.1021/acsomega.1c01124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 06/08/2021] [Indexed: 06/13/2023]
Abstract
Development of adaptive self-regulating materials and chemical-biological systems-self-healing, self-regulating, etc.-is an advanced modern trend. The very sensitive pH-controlled functionality of supramolecular assemblies is a very useful tool for chemical and biochemical implementations. However, the assembly process can be tuned by various factors that can be used for both better functionality control and further functionalization such as active species, e.g., drugs and dyes, and encapsulation. Here, the effect of a dye, sodium fluorescein (uranine) (FL), on the formation of a self-assembled melamine cyanurate (M-CA) structure is investigated and calculated with density functional theory (DFT) and molecular dynamics. Interestingly, the dye greatly affects the self-assembly process at early stages from the formation of dimers, trimers, and tetramer to nucleation control. The supramolecular structure disassembly and subsequent release of trapped dye occurred under both high- and low-pH conditions. This system can be used for time-prolonged bacterial staining and development of supramolecular capsules for the system chemistry approach.
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Affiliation(s)
- Nfayem Imoro
- ITMO
University, Lomonosova str. 9, St. Petersburg 191002, Russian Federation
| | | | - Pavel V. Nesterov
- ITMO
University, Lomonosova str. 9, St. Petersburg 191002, Russian Federation
| | | | - Dmitry Gets
- ITMO
University, Lomonosova str. 9, St. Petersburg 191002, Russian Federation
| | - Anna Nebalueva
- ITMO
University, Lomonosova str. 9, St. Petersburg 191002, Russian Federation
| | - Filipp V. Lavrentev
- ITMO
University, Lomonosova str. 9, St. Petersburg 191002, Russian Federation
| | | | - Nikolay D. Kondratyuk
- Moscow
Institute of Physics and Technology, 9 Institutskiy per., Dolgoprudny, Moscow Region 141701, Russian Federation
- Joint
Institute for High Temperatures of the Russian Academy of Sciences, 13 Izhorskaya Bd 2, Moscow 125412, Russian Federation
| | - Nikita D. Orekhov
- Moscow
Institute of Physics and Technology, 9 Institutskiy per., Dolgoprudny, Moscow Region 141701, Russian Federation
- Joint
Institute for High Temperatures of the Russian Academy of Sciences, 13 Izhorskaya Bd 2, Moscow 125412, Russian Federation
- Bauman
Moscow State Technical University, 2nd Baumanskaya Str., 5, Moscow 105005, Russia
| | - Ekaterina V. Skorb
- ITMO
University, Lomonosova str. 9, St. Petersburg 191002, Russian Federation
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50
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Fan S, Nedev H, Vijayan R, Iorga BI, Beckstein O. Precise force-field-based calculations of octanol-water partition coefficients for the SAMPL7 molecules. J Comput Aided Mol Des 2021; 35:853-870. [PMID: 34232435 PMCID: PMC8397498 DOI: 10.1007/s10822-021-00407-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 06/22/2021] [Indexed: 10/20/2022]
Abstract
We predicted water-octanol partition coefficients for the molecules in the SAMPL7 challenge with explicit solvent classical molecular dynamics (MD) simulations. Water hydration free energies and octanol solvation free energies were calculated with a windowed alchemical free energy approach. Three commonly used force fields (AMBER GAFF, CHARMM CGenFF, OPLS-AA) were tested. Special emphasis was placed on converging all simulations, using a criterion developed for the SAMPL6 challenge. In aggregate, over 1000 [Formula: see text]s of simulations were performed, with some free energy windows remaining not fully converged even after 1 [Formula: see text]s of simulation time. Nevertheless, the amount of sampling produced [Formula: see text] estimates with a precision of 0.1 log units or better for converged simulations. Despite being probably as fully sampled as can expected and is feasible, the agreement with experiment remained modest for all force fields, with no force field performing better than 1.6 in root mean squared error. Overall, our results indicate that a large amount of sampling is necessary to produce precise [Formula: see text] predictions for the SAMPL7 compounds and that high precision does not necessarily lead to high accuracy. Thus, fundamental problems remain to be solved for physics-based [Formula: see text] predictions.
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Affiliation(s)
- Shujie Fan
- Department of Physics, Arizona State University, P.O. Box 871504, Tempe, AZ, 85287-1504, USA
| | - Hristo Nedev
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, Labex LERMIT, 1 Avenue de la Terrasse, 91198, Gif-sur-Yvette, France
| | - Ranjit Vijayan
- Department of Biology, College of Science, United Arab Emirates University, PO Box 15551, Al Ain, UAE
| | - Bogdan I Iorga
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, Labex LERMIT, 1 Avenue de la Terrasse, 91198, Gif-sur-Yvette, France.
| | - Oliver Beckstein
- Department of Physics and Center for Biological Physics, Arizona State University, P.O. Box 871504, Tempe, AZ, 85287-1504, USA.
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