1
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Wang S, Walker-Gibbons R, Watkins B, Flynn M, Krishnan M. A charge-dependent long-ranged force drives tailored assembly of matter in solution. NATURE NANOTECHNOLOGY 2024; 19:485-493. [PMID: 38429493 PMCID: PMC11026162 DOI: 10.1038/s41565-024-01621-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 01/25/2024] [Indexed: 03/03/2024]
Abstract
The interaction between charged objects in solution is generally expected to recapitulate two central principles of electromagnetics: (1) like-charged objects repel, and (2) they do so regardless of the sign of their electrical charge. Here we demonstrate experimentally that the solvent plays a hitherto unforeseen but crucial role in interparticle interactions, and importantly, that interactions in the fluid phase can break charge-reversal symmetry. We show that in aqueous solution, negatively charged particles can attract at long range while positively charged particles repel. In solvents that exhibit an inversion of the net molecular dipole at an interface, such as alcohols, we find that the converse can be true: positively charged particles may attract whereas negatives repel. The observations hold across a wide variety of surface chemistries: from inorganic silica and polymeric particles to polyelectrolyte- and polypeptide-coated surfaces in aqueous solution. A theory of interparticle interactions that invokes solvent structuring at an interface captures the observations. Our study establishes a nanoscopic interfacial mechanism by which solvent molecules may give rise to a strong and long-ranged force in solution, with immediate ramifications for a range of particulate and molecular processes across length scales such as self-assembly, gelation and crystallization, biomolecular condensation, coacervation, and phase segregation.
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Affiliation(s)
- Sida Wang
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Rowan Walker-Gibbons
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Bethany Watkins
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Melissa Flynn
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Madhavi Krishnan
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, UK.
- The Kavli Institute for Nanoscience Discovery, Oxford, UK.
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2
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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] [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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3
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Rahimi AM, Jamali S, Bardhan JP, Lustig SR. Solvation Thermodynamics of Solutes in Water and Ionic Liquids Using the Multiscale Solvation-Layer Interface Condition Continuum Model. J Chem Theory Comput 2022; 18:5539-5558. [PMID: 36001344 DOI: 10.1021/acs.jctc.2c00248] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular assembly processes are generally driven by thermodynamic properties in solutions. Atomistic modeling can be very helpful in designing and understanding complex systems, except that bulk solvent is very inefficient to treat explicitly as discrete molecules. In this work, we develop and assess two multiscale solvation models for computing solvation thermodynamic properties. The new SLIC/CDC model combines continuum solvent electrostatics based on the solvent layer interface condition (SLIC) with new statistical thermodynamic models for hydrogen bonding and nonpolar modes: cavity formation, dispersion interactions, combinatorial mixing (CDC). Given the structures of 500 solutes, the SLIC/CDC model predicts Gibbs energies of solvation in water with an average accuracy better than 1 kcal/mol, when compared to experimental measurements, and better than 0.8 kcal/mol, when compared to explicit-solvent molecular dynamics simulations. The individual SLIC/CDC energy mode values agree quantitatively with those computed from explicit-solvent molecular dynamics. The previously published SLIC/SASA multiscale model combines the SLIC continuum electrostatic model with the solvent-accessible surface area (SASA) nonpolar energy mode. With our new, improved parametrization method, the SLIC/SASA model now predicts Gibbs energies of solvation with better than 1.4 kcal/mol average accuracy in aqueous systems, compared to experimental and explicit-solvent molecular dynamics, and better than 1.6 kcal/mol average accuracy in ionic liquids, compared to explicit-solvent molecular dynamics. Both models predict solvation entropies, and are the first implicit-solvation models capable of predicting solvation heat capacities.
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Affiliation(s)
- Ali Mehdizadeh Rahimi
- Department of Mechanical and Industrial Engineering, Northeastern University, 360 Huntington Ave., Boston Massachusetts 02115, United States
| | - Safa Jamali
- Department of Mechanical and Industrial Engineering, Northeastern University, 360 Huntington Ave., Boston Massachusetts 02115, United States
| | - Jaydeep P Bardhan
- Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, Washington 99354, United States
| | - Steven R Lustig
- Department of Chemical Engineering, Northeastern University, 360 Huntington Ave., Boston, Massachusetts 02115, United States
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4
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Radtke V, Gebel N, Priester D, Ermantraut A, Bäuerle M, Himmel D, Stroh R, Koslowski T, Leito I, Krossing I. Measurements and Utilization of Consistent Gibbs Energies of Transfer of Single Ions: Towards a Unified Redox Potential Scale for All Solvents. Chemistry 2022; 28:e202200509. [PMID: 35446995 PMCID: PMC9401597 DOI: 10.1002/chem.202200509] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Indexed: 11/08/2022]
Abstract
Utilizing the "ideal" ionic liquid salt bridge to measure Gibbs energies of transfer of silver ions between the solvents water, acetonitrile, propylene carbonate and dimethylformamide results in a consistent data set with a precision of 0.6 kJ mol-1 over 87 measurements in 10 half-cells. This forms the basis for a coherent experimental thermodynamic framework of ion solvation chemistry. In addition, we define the solvent independent pe abs H 2 O - and the E abs H 2 O values that account for the electronating potential of any redox system similar to the pH abs H 2 O value of a medium that accounts for its protonating potential. This E abs H 2 O scale is thermodynamically well-defined enabling a straightforward comparison of the redox potentials (reducities) of all media with respect to the aqueous redox potential scale, hence unifying all conventional solvents' redox potential scales. Thus, using the Gibbs energy of transfer of the silver ion published herein, one can convert and unify all hitherto published redox potentials measured, for example, against ferrocene, to the E abs H 2 O scale.
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Affiliation(s)
- Valentin Radtke
- Institut für Anorganische und Analytische ChemieFreiburger Materialforschungszentrum (FMF) andFreiburg Center for Interactive Materials and Bioinspired Technologies (FIT)Albert-Ludwigs-Universität FreiburgAlbertstr. 2179104FreiburgGermany
| | - Niklas Gebel
- Institut für Anorganische und Analytische ChemieFreiburger Materialforschungszentrum (FMF) andFreiburg Center for Interactive Materials and Bioinspired Technologies (FIT)Albert-Ludwigs-Universität FreiburgAlbertstr. 2179104FreiburgGermany
| | - Denis Priester
- Institut für Anorganische und Analytische ChemieFreiburger Materialforschungszentrum (FMF) andFreiburg Center for Interactive Materials and Bioinspired Technologies (FIT)Albert-Ludwigs-Universität FreiburgAlbertstr. 2179104FreiburgGermany
| | - Andreas Ermantraut
- Institut für Anorganische und Analytische ChemieFreiburger Materialforschungszentrum (FMF) andFreiburg Center for Interactive Materials and Bioinspired Technologies (FIT)Albert-Ludwigs-Universität FreiburgAlbertstr. 2179104FreiburgGermany
| | - Monika Bäuerle
- Institut für Anorganische und Analytische ChemieFreiburger Materialforschungszentrum (FMF) andFreiburg Center for Interactive Materials and Bioinspired Technologies (FIT)Albert-Ludwigs-Universität FreiburgAlbertstr. 2179104FreiburgGermany
| | - Daniel Himmel
- Institut für Anorganische und Analytische ChemieFreiburger Materialforschungszentrum (FMF) andFreiburg Center for Interactive Materials and Bioinspired Technologies (FIT)Albert-Ludwigs-Universität FreiburgAlbertstr. 2179104FreiburgGermany
| | - Regina Stroh
- Institut für Anorganische und Analytische ChemieFreiburger Materialforschungszentrum (FMF) andFreiburg Center for Interactive Materials and Bioinspired Technologies (FIT)Albert-Ludwigs-Universität FreiburgAlbertstr. 2179104FreiburgGermany
| | - Thorsten Koslowski
- Institut für Physikalische ChemieAlbert-Ludwigs-Universität FreiburgAlbertstr. 23a79104FreiburgGermany
| | - Ivo Leito
- Institute of ChemistryUniversity of TartuRavila 14a Str50411TartuEstonia
| | - Ingo Krossing
- Institut für Anorganische und Analytische ChemieFreiburger Materialforschungszentrum (FMF) andFreiburg Center for Interactive Materials and Bioinspired Technologies (FIT)Albert-Ludwigs-Universität FreiburgAlbertstr. 2179104FreiburgGermany
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5
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Walker-Gibbons R, Kubincová A, Hünenberger PH, Krishnan M. The Role of Surface Chemistry in the Orientational Behavior of Water at an Interface. J Phys Chem B 2022; 126:4697-4710. [PMID: 35726865 PMCID: PMC9251758 DOI: 10.1021/acs.jpcb.2c01752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 05/18/2022] [Indexed: 11/30/2022]
Abstract
Molecular dynamics studies have demonstrated that molecular water at an interface, with either a gas or a solid, displays anisotropic orientational behavior in contrast to its bulk counterpart. This effect has been recently implicated in the like-charge attraction problem for colloidal particles in solution. Here, negatively charged particles in solution display a long-ranged attraction where continuum electrostatic theory predicts monotonically repulsive interactions, particularly in solutions with monovalent salt ions at low ionic strength. Anisotropic orientational behavior of solvent molecules at an interface gives rise to an excess interfacial electrical potential which we suggest generates an additional solvation contribution to the total free energy that is traditionally overlooked in continuum descriptions of interparticle interactions in solution. In the present investigation we perform molecular dynamics simulation based calculations of the interfacial potential using realistic surface models representing various chemistries as well as different solvents. Similar to previous work that focused on simple model surfaces constructed by using oxygen atoms, we find that solvents at more realistic model surfaces exhibit substantial anisotropic orientational behavior. We explore the dependence of the interfacial solvation potential on surface properties such as surface group chemistry and group density at silica and carboxylated polystyrene interfaces. For water, we note surprisingly good agreement between results obtained for a simple O-atom wall and more complex surface models, suggesting a general qualitative consistency of the interfacial solvation effect for surfaces in contact with water. In contrast, for an aprotic solvent such as DMSO, surface chemistry appears to exert a stronger influence on the sign and magnitude of the interfacial solvation potential. The study carries broad implications for molecular-scale interactions and may find relevance in explaining a range of phenomena in soft-matter physics and cell biology.
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Affiliation(s)
- Rowan Walker-Gibbons
- Physical
& Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Alžbeta Kubincová
- Laboratory
of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Philippe H. Hünenberger
- Laboratory
of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Madhavi Krishnan
- Physical
& Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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6
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Behjatian A, Walker-Gibbons R, Schekochihin AA, Krishnan M. Nonmonotonic Pair Potentials in the Interaction of Like-Charged Objects in Solution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:786-800. [PMID: 34981941 DOI: 10.1021/acs.langmuir.1c02801] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We consider the long-standing like-charge attraction problem, wherein under certain conditions, similarly charged spheres suspended in aqueous electrolyte have been observed to display a minimum in their interaction potential, contrary to the intuitively expected monotonically varying repulsion. Recently, we described an interfacial mechanism invoking the molecular nature of the solvent that explains this anomalous experimental observation. In our model for the interaction of negatively charged particles in water, the minimum in the pair potential results from the superposition of competing contributions to the total free energy. One of these contributions is the canonical repulsive electrostatic term, whereas the other is a solvation-induced attractive contribution. We find that whereas both contributions grow approximately exponentially with decreasing interparticle separation, the occurrence of a stable, long-ranged minimum in the pair potential arises from differences in the precise interparticle separation dependence of the two terms. Specifically, the interfacial solvation term exhibits a more gradual decay with distance than the electrostatic repulsion, permitting the attractive contribution to dominate the interaction at large distances. Importantly, these disparities become evident in quantities calculated from exact numerical solutions to the governing nonlinear Poisson-Boltzmann (PB) equation for the spatial electrical potential distribution in the system. In marked contrast, we find that the linearized PB equation, applicable in the regime of low surface electrical potentials, does not support nonmonotonic trends in the total interaction free energy within the present model. Our results point to the importance of exact descriptions of electrostatic interactions in real systems that most often do not subscribe to particular mathematical limits where analytical approximations may provide a sufficiently accurate description of the problem.
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Affiliation(s)
- Ali Behjatian
- Physical & Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Rowan Walker-Gibbons
- Physical & Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Alexander A Schekochihin
- Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
- Merton College, Merton Street, Oxford OX1 4JD, United Kingdom
| | - Madhavi Krishnan
- Physical & Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
- Merton College, Merton Street, Oxford OX1 4JD, United Kingdom
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7
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Molina-Muriel R, Romero JR, Li Y, Aragay G, Ballester P. The effect of solvent on the binding of anions and ion-pairs with a neutral [2]rotaxane. Org Biomol Chem 2021; 19:9986-9995. [PMID: 34755156 DOI: 10.1039/d1ob01845k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In this work we report the binding properties of rotaxane 1 towards a series of tetraalkylammonium salts of Cl-, OCN- and NO3- anions in acetone and a CHCl3/MeOH solvent mixture. We used 1H NMR titrations and Isothermal Titration Calorimetry (ITC) experiments to monitor and analyze the binding processes. We compared the obtained results with those previously described by us in chloroform solution. In acetone solution, the determined binding constants for the 1 : 1 complexes were 1 to 3 orders of magnitude larger than those measured in chloroform, a less competitive solvent for hydrogen-bonding. The thermodynamic signatures of the binding processes in acetone, determined by ITC experiments, revealed favorable enthalpic and entropic contributions having similar magnitudes. These results suggested that solvation/desolvation processes in acetone play a significant role in the binding processes. Conversely, the addition of just 5% of methanol to chloroform solutions of 1 significantly reduces the magnitude of the binding constants of all studied ion-pairs. In this solvent mixture, the entropy term is also favorable but it does not compensate the experienced loss of binding enthalpy. Moreover, in acetone solution, the addition of the Cl- and OCN- tetraalkylammonium salts in excess (more than 1 equiv.) led to the immediate appearance of 2 : 1 complexes. Related high-stoichiometry complexes are not observed in the solvent mixture (CHCl3/MeOH 95/5). In chloroform, a large excess of the salt (> 6 equiv.) is required for its formation. From the analysis of the obtained binding data we infer that, in acetone and in CHCl3/MeOH mixture, the formed complexes are mainly anionic.
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Affiliation(s)
- Ricardo Molina-Muriel
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST), Avgda. Països Catalans 16, 43007 Tarragona, Spain.
| | - J Ramón Romero
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST), Avgda. Països Catalans 16, 43007 Tarragona, Spain.
| | - Yifan Li
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST), Avgda. Països Catalans 16, 43007 Tarragona, Spain. .,Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili (URV), c/Marcel·lí Domingo 1, 43007 Tarragona, Spain
| | - Gemma Aragay
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST), Avgda. Països Catalans 16, 43007 Tarragona, Spain.
| | - Pablo Ballester
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST), Avgda. Països Catalans 16, 43007 Tarragona, Spain. .,ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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8
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König G, Ries B, Hünenberger PH, Riniker S. Efficient Alchemical Intermediate States in Free Energy Calculations Using λ-Enveloping Distribution Sampling. J Chem Theory Comput 2021; 17:5805-5815. [PMID: 34476947 DOI: 10.1021/acs.jctc.1c00418] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Alchemical free energy calculations generally require intermediate states along a coupling parameter λ to establish sufficient phase space overlap for obtaining converged results. Such intermediate states can also be engineered to lower the energy barriers and, consequently, reduce the required sampling time. The recently introduced λ-enveloping distribution sampling (λ-EDS) scheme combines the properties of the minimum variance pathway and the EDS methods to improve sampling and allow for larger steps along the alchemical pathway compared to conventional approaches. This scheme also eliminates the need for soft-core potentials and retains the behavior of conventional λ-intermediate states as a limiting case. In this study, an automated procedure is developed to select the parameters of λ-EDS for optimal performance. The underlying theory is illustrated based on simulations of simple test systems (bond length changes in harmonic oscillators, mutations of dihedral angles, and charge creation in water), as well as on the calculation of the absolute hydration free energies of 12 small organic molecules.
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Affiliation(s)
- Gerhard König
- Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland.,Centre for Enzyme Innovation, University of Portsmouth, St. Michael's Building, PO1 2DT Portsmouth, U.K
| | - Benjamin Ries
- Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Philippe H Hünenberger
- Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Sereina Riniker
- Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
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9
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Herbert JM. Dielectric continuum methods for quantum chemistry. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2021. [DOI: 10.1002/wcms.1519] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- John M. Herbert
- Department of Chemistry and Biochemistry The Ohio State University Columbus Ohio USA
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10
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Malloum A, Fifen JJ, Conradie J. Determination of the absolute solvation free energy and enthalpy of the proton in solutions. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.114919] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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11
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Öhlknecht C, Petrov D, Engele P, Kröß C, Sprenger B, Fischer A, Lingg N, Schneider R, Oostenbrink C. Enhancing the promiscuity of a member of the Caspase protease family by rational design. Proteins 2020; 88:1303-1318. [PMID: 32432825 PMCID: PMC7497161 DOI: 10.1002/prot.25950] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 03/19/2020] [Accepted: 04/29/2020] [Indexed: 12/12/2022]
Abstract
The N-terminal cleavage of fusion tags to restore the native N-terminus of recombinant proteins is a challenging task and up to today, protocols need to be optimized for different proteins individually. Within this work, we present a novel protease that was designed in-silico to yield enhanced promiscuity toward different N-terminal amino acids. Two mutations in the active-site amino acids of human Caspase-2 were determined to increase the recognition of branched amino-acids, which show only poor binding capabilities in the unmutated protease. These mutations were determined by sequential and structural comparisons of Caspase-2 and Caspase-3 and their effect was additionally predicted using free-energy calculations. The two mutants proposed in the in-silico studies were expressed and in-vitro experiments confirmed the simulation results. Both mutants showed not only enhanced activities toward branched amino acids, but also smaller, unbranched amino acids. We believe that the created mutants constitute an important step toward generalized procedures to restore original N-termini of recombinant fusion proteins.
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Affiliation(s)
- Christoph Öhlknecht
- Institute of Molecular Modeling and SimulationUniversity of Natural Resources and Life SciencesViennaAustria
- Austrian Centre of Industrial BiotechnologyViennaAustria
| | - Drazen Petrov
- Institute of Molecular Modeling and SimulationUniversity of Natural Resources and Life SciencesViennaAustria
| | - Petra Engele
- Institute of Biochemistry and Center of Molecular Biosciences InnsbruckUniversity of InnsbruckInnsbruckAustria
- Austrian Centre of Industrial BiotechnologyViennaAustria
| | - Christina Kröß
- Institute of Biochemistry and Center of Molecular Biosciences InnsbruckUniversity of InnsbruckInnsbruckAustria
- Austrian Centre of Industrial BiotechnologyViennaAustria
| | - Bernhard Sprenger
- Institute of Biochemistry and Center of Molecular Biosciences InnsbruckUniversity of InnsbruckInnsbruckAustria
- Austrian Centre of Industrial BiotechnologyViennaAustria
| | | | - Nico Lingg
- Austrian Centre of Industrial BiotechnologyViennaAustria
| | - Rainer Schneider
- Institute of Biochemistry and Center of Molecular Biosciences InnsbruckUniversity of InnsbruckInnsbruckAustria
| | - Chris Oostenbrink
- Institute of Molecular Modeling and SimulationUniversity of Natural Resources and Life SciencesViennaAustria
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12
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Young JM, Mondal A, Barckholtz TA, Kiss G, Koziol L, Panagiotopoulos AZ. Predicting chemical reaction equilibria in molten carbonate fuel cells via molecular simulations. AIChE J 2020. [DOI: 10.1002/aic.16988] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Jeffrey M. Young
- Department of Chemical and Biological Engineering Princeton University Princeton New Jersey USA
| | - Anirban Mondal
- Department of Chemical and Biological Engineering Princeton University Princeton New Jersey USA
| | | | - Gabor Kiss
- ExxonMobil Research and Engineering Annandale New Jersey USA
| | - Lucas Koziol
- ExxonMobil Research and Engineering Annandale New Jersey USA
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13
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Xin X, Niu X, Liu W, Wang D. Hybrid Solvation Model with First Solvation Shell for Calculation of Solvation Free Energy. Chemphyschem 2020; 21:762-769. [PMID: 32154979 DOI: 10.1002/cphc.202000039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/15/2020] [Indexed: 02/03/2023]
Abstract
We present a hybrid solvation model with first solvation shell to calculate solvation free energies. This hybrid model combines the quantum mechanics and molecular mechanics methods with the analytical expression based on the Born solvation model to calculate solvation free energies. Based on calculated free energies of solvation and reaction profiles in gas phase, we set up a unified scheme to predict reaction profiles in solution. The predicted solvation free energies and reaction barriers are compared with experimental results for twenty bimolecular nucleophilic substitution reactions. These comparisons show that our hybrid solvation model can predict reliable solvation free energies and reaction barriers for chemical reactions of small molecules in aqueous solution.
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Affiliation(s)
- Xin Xin
- College of Physics and Electronics, Shandong Normal University, Jinan, Shandong, 250014, China
| | - Xiao Niu
- College of Physics and Electronics, Shandong Normal University, Jinan, Shandong, 250014, China
| | - Wanqi Liu
- College of Physics and Electronics, Shandong Normal University, Jinan, Shandong, 250014, China
| | - Dunyou Wang
- College of Physics and Electronics, Shandong Normal University, Jinan, Shandong, 250014, China
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14
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Kubincová A, Hünenberger PH, Krishnan M. Interfacial solvation can explain attraction between like-charged objects in aqueous solution. J Chem Phys 2020; 152:104713. [PMID: 32171222 DOI: 10.1063/1.5141346] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Over the past few decades, the experimental literature has consistently reported observations of attraction between like-charged colloidal particles and macromolecules in aqueous solution. Examples include nucleic acids and colloidal particles in the bulk solution and under confinement, and biological liquid-liquid phase separation. This observation is at odds with the intuitive expectation of an interparticle repulsion that decays monotonically with distance. Although attraction between like-charged particles can be rationalized theoretically in the strong-coupling regime, e.g., in the presence of multivalent counterions, recurring accounts of long-range attraction in aqueous solution containing monovalent ions at low ionic strength have posed an open conundrum. Here, we show that the behavior of molecular water at an interface-traditionally disregarded in the continuum electrostatics picture-provides a mechanism to explain the attraction between like-charged objects in a broad spectrum of experiments. This basic principle will have important ramifications in the ongoing quest to better understand intermolecular interactions in solution.
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Affiliation(s)
- Alžbeta Kubincová
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Philippe H Hünenberger
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Madhavi Krishnan
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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15
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Osawa K, Tagaya H, Kondo SI. Naked Eye Detection of Anions by 2,2′-Bianthracene Derivative Bearing Urea Groups in Various Organic Solvents. CHEM LETT 2020. [DOI: 10.1246/cl.190924] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Kohei Osawa
- Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Hideyuki Tagaya
- Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Shin-ichi Kondo
- Department of Chemistry, Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-Machi, Yamagata 990-8560, Japan
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16
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Duignan TT, Zhao XS. The Born model can accurately describe electrostatic ion solvation. Phys Chem Chem Phys 2020; 22:25126-25135. [DOI: 10.1039/d0cp04148c] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The solvation free energies of ions in water are consistent with the Born linear response model if the centre on which the ion–water repulsion force acts is moved from the oxygen atom towards the hydrogens.
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Affiliation(s)
- Timothy T. Duignan
- School of Chemical Engineering
- The University of Queensland
- St Lucia
- Australia
| | - X. S. Zhao
- School of Chemical Engineering
- The University of Queensland
- St Lucia
- Australia
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17
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Prasetyo N, Hünenberger PH, Hofer TS. Single-Ion Thermodynamics from First Principles: Calculation of the Absolute Hydration Free Energy and Single-Electrode Potential of Aqueous Li + Using ab Initio Quantum Mechanical/Molecular Mechanical Molecular Dynamics Simulations. J Chem Theory Comput 2018; 14:6443-6459. [PMID: 30284829 DOI: 10.1021/acs.jctc.8b00729] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A recently proposed thermodynamic integration (TI) approach formulated in the framework of quantum mechanical/molecular mechanical molecular dynamics (QM/MM MD) simulations is applied to study the structure, dynamics, and absolute intrinsic hydration free energy Δs GM+,wat◦ of the Li+ ion at a correlated ab initio level of theory. Based on the results, standard values (298.15 K, ideal gas at 1 bar, ideal solute at 1 molal) for the absolute intrinsic hydration free energy [Formula: see text] of the proton, the surface electric potential jump χwat◦ upon entering bulk water, and the absolute single-electrode potential [Formula: see text] of the reference hydrogen electrode are calculated to be -1099.9 ± 4.2 kJ·mol-1, 0.13 ± 0.08 V, and 4.28 ± 0.04 V, respectively, in excellent agreement with the standard values recommended by Hünenberger and Reif on the basis of an extensive evaluation of the available experimental data (-1100 ± 5 kJ·mol-1, 0.13 ± 0.10 V, and 4.28 ± 0.13 V). The simulation results for Li+ are also compared to those for Na+ and K+ from a previous study in terms of relative hydration free energies ΔΔs GM+,wat◦ and relative electrode potentials [Formula: see text]. The calculated values are found to agree extremely well with the experimental differences in standard conventional hydration free energies ΔΔs GM+,wat• and redox potentials [Formula: see text]. The level of agreement between simulation and experiment, which is quantitative within error bars, underlines the substantial accuracy improvement achieved by applying a highly demanding QM/MM approach at the resolution-of-identity second-order Møller-Plesset perturbation (RIMP2) level over calculations relying on purely molecular mechanical or density functional theory (DFT) descriptions. A detailed analysis of the structural and dynamical properties of the Li+ hydrate indicates that a correct description of the solvation structure and dynamics is achieved as well at this level of theory. Consideration of the QM/MM potential-energy components also shows that the partitioning into QM and MM zones does not induce any significant energetic artifact for the system considered.
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Affiliation(s)
- Niko Prasetyo
- Theoretical Chemistry Division, Institute of General, Inorganic and Theoretical Chemistry , University of Innsbruck , Innrain 80-82 , A-6020 Innsbruck , Austria.,Austria-Indonesia Centre (AIC) for Computational Chemistry , Universitas Gadjah Mada , Sekip Utara , Yogyakarta 55281 , Indonesia.,Department of Chemistry, Faculty of Mathematics and Natural Sciences , Universitas Gadjah Mada , Sekip Utara , Yogyakarta 55281 , Indonesia
| | - Philippe H Hünenberger
- Laboratorium für Physikalische Chemie , ETH Zürich, ETH-Hönggerberg , HCI Building , CH-8093 Zürich , Switzerland
| | - Thomas S Hofer
- Theoretical Chemistry Division, Institute of General, Inorganic and Theoretical Chemistry , University of Innsbruck , Innrain 80-82 , A-6020 Innsbruck , Austria
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18
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Sarhangi SM, Waskasi MM, Hashemianzadeh SM, Matyushov DV. Interfacial structural crossover and hydration thermodynamics of charged C 60 in water. Phys Chem Chem Phys 2018; 20:27069-27081. [PMID: 30328845 DOI: 10.1039/c8cp05422c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Classical molecular dynamics simulations of the hydration thermodynamics, structure, and dynamics of water in hydration shells of charged buckminsterfullerenes are presented in this study. Charging of fullerenes leads to a structural transition in the hydration shell, accompanied by creation of a significant population of dangling O-H bonds pointing toward the solute. In contrast to the well accepted structure-function paradigm, this interfacial structural transition causes nearly no effect on either the dynamics of hydration water or on the solvation thermodynamics. Linear response to the solute charge is maintained despite significant structural changes in the hydration shell, and solvation thermodynamic potentials are nearly insensitive to the altering structure. Only solvation heat capacities, which are higher thermodynamic derivatives of the solvation free energy, indicate some sensitivity to the local hydration structure. We have separated the solvation thermodynamic potentials into direct solute-solvent interactions and restructuring of the hydration shell and analyzed the relative contributions of electrostatic and nonpolar interactions to the solvation thermodynamics.
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Affiliation(s)
- Setare Mostajabi Sarhangi
- Molecular Simulation Research Laboratory, Department of Chemistry, Iran University of Science and Technology, Tehran 16846-13114, Iran
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19
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Duignan TT, Baer MD, Mundy CJ. Understanding the scale of the single ion free energy: A critical test of the tetra-phenyl arsonium and tetra-phenyl borate assumption. J Chem Phys 2018; 148:222819. [PMID: 29907030 DOI: 10.1063/1.5020171] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The tetra-phenyl arsonium and tetra-phenyl borate (TATB) assumption is a commonly used extra-thermodynamic assumption that allows single ion free energies to be split into cationic and anionic contributions. The assumption is that the values for the TATB salt can be divided equally. This is justified by arguing that these large hydrophobic ions will cause a symmetric response in water. Experimental and classical simulation work has raised potential flaws with this assumption, indicating that hydrogen bonding with the phenyl ring may favor the solvation of the TB- anion. Here, we perform ab initio molecular dynamics simulations of these ions in bulk water demonstrating that there are significant structural differences. We quantify our findings by reproducing the experimentally observed vibrational shift for the TB- anion and confirm that this is associated with hydrogen bonding with the phenyl rings. Finally, we demonstrate that this results in a substantial energetic preference of the water to solvate the anion. Our results suggest that the validity of the TATB assumption, which is still widely used today, should be reconsidered experimentally in order to properly reference single ion solvation free energy, enthalpy, and entropy.
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Affiliation(s)
- Timothy T Duignan
- Physical Science Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, USA
| | - Marcel D Baer
- Physical Science Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, USA
| | - Christopher J Mundy
- Physical Science Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, USA
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20
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Pollard TP, Beck TL. Re-examining the tetraphenyl-arsonium/tetraphenyl-borate (TATB) hypothesis for single-ion solvation free energies. J Chem Phys 2018; 148:222830. [DOI: 10.1063/1.5024209] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Travis P. Pollard
- Electrochemistry Branch, US Army Research Laboratory, Adelphi, Maryland 20852, USA
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, USA
| | - Thomas L. Beck
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, USA
- Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221, USA
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21
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Cox SJ, Geissler PL. Interfacial ion solvation: Obtaining the thermodynamic limit from molecular simulations. J Chem Phys 2018; 148:222823. [DOI: 10.1063/1.5020563] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Stephen J. Cox
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Phillip L. Geissler
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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22
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Hofer TS, Hünenberger PH. Absolute proton hydration free energy, surface potential of water, and redox potential of the hydrogen electrode from first principles: QM/MM MD free-energy simulations of sodium and potassium hydration. J Chem Phys 2018; 148:222814. [DOI: 10.1063/1.5000799] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- Thomas S. Hofer
- Theoretical Chemistry Division, Institute of General, Inorganic and Theoretical Chemistry, Centre for Chemistry and Biomedicine, University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria
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23
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Sehnem AL, Niether D, Wiegand S, Figueiredo Neto AM. Thermodiffusion of Monovalent Organic Salts in Water. J Phys Chem B 2018; 122:4093-4100. [DOI: 10.1021/acs.jpcb.8b01152] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Doreen Niether
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
| | - Simone Wiegand
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
- Department für Chemie - Physikalische Chemie, Universität zu Köln, 50939 Cologne, Germany
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24
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Himmel D, Radtke V, Butschke B, Krossing I. Grundlegende Bemerkungen zur Azidität. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201709057] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Daniel Himmel
- Institut für Anorganische und Analytische Chemie, und Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstraße 21 79104 Freiburg Deutschland
| | - Valentin Radtke
- Institut für Anorganische und Analytische Chemie, und Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstraße 21 79104 Freiburg Deutschland
| | - Burkhard Butschke
- Institut für Anorganische und Analytische Chemie, und Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstraße 21 79104 Freiburg Deutschland
| | - Ingo Krossing
- Institut für Anorganische und Analytische Chemie, und Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstraße 21 79104 Freiburg Deutschland
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25
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Himmel D, Radtke V, Butschke B, Krossing I. Basic Remarks on Acidity. Angew Chem Int Ed Engl 2018; 57:4386-4411. [PMID: 29171707 DOI: 10.1002/anie.201709057] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/16/2017] [Indexed: 12/21/2022]
Abstract
This Review provides a unified view on Brønsted acidity. For this purpose, a brief overview of the concepts acidity, acid strengths, and pH value is given, including problems, proposed solutions, and the use of the pHabs /pHabsH2O scale as a unifying concept. Thereafter, some examples of the accessibility and application of unified pHabs values are given. The Review is rounded off with the analogy of acid-base chemistry to redox chemistry with the introduction of the unified redox scale peabs . The combination of pHabs and peabs values in the protoelectric potential map (PPM), as elaborated in ongoing studies on the thermochemistry of single ions, provides a means to classify and to compare all possible acid-base/redox reactions in a medium-independent and, thus, unified fashion.
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Affiliation(s)
- Daniel Himmel
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF), Universität Freiburg, Albertstrasse 21, 79104, Freiburg, Germany
| | - Valentin Radtke
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF), Universität Freiburg, Albertstrasse 21, 79104, Freiburg, Germany
| | - Burkhard Butschke
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF), Universität Freiburg, Albertstrasse 21, 79104, Freiburg, Germany
| | - Ingo Krossing
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF), Universität Freiburg, Albertstrasse 21, 79104, Freiburg, Germany
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26
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Fiala T, Sleziakova K, Marsalek K, Salvadori K, Sindelar V. Thermodynamics of Halide Binding to a Neutral Bambusuril in Water and Organic Solvents. J Org Chem 2018; 83:1903-1912. [DOI: 10.1021/acs.joc.7b02846] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Tomas Fiala
- Department of Chemistry and
RECETOX, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Kristina Sleziakova
- Department of Chemistry and
RECETOX, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Kamil Marsalek
- Department of Chemistry and
RECETOX, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Karolina Salvadori
- Department of Chemistry and
RECETOX, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Vladimir Sindelar
- Department of Chemistry and
RECETOX, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
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27
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Duignan TT, Baer MD, Schenter GK, Mundy CJ. Electrostatic solvation free energies of charged hard spheres using molecular dynamics with density functional theory interactions. J Chem Phys 2017; 147:161716. [DOI: 10.1063/1.4994912] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Timothy T. Duignan
- Physical Science Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA
| | - Marcel D. Baer
- Physical Science Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA
| | - Gregory K. Schenter
- Physical Science Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA
| | - Chistopher J. Mundy
- Department of Chemical Engineering, University of Washington, Seattle, Washington 98185, USA
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28
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Molavi Tabrizi A, Goossens S, Mehdizadeh Rahimi A, Knepley M, Bardhan JP. Predicting solvation free energies and thermodynamics in polar solvents and mixtures using a solvation-layer interface condition. J Chem Phys 2017. [DOI: 10.1063/1.4977037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Amirhossein Molavi Tabrizi
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts 02115, USA
| | - Spencer Goossens
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts 02115, USA
| | - Ali Mehdizadeh Rahimi
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts 02115, USA
| | - Matthew Knepley
- Department of Computational and Applied Mathematics, Rice University, Houston, Texas 77005, USA
| | - Jaydeep P. Bardhan
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts 02115, USA
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29
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Simonson T, Hummer G, Roux B. Equivalence of M- and P-Summation in Calculations of Ionic Solvation Free Energies. J Phys Chem A 2017; 121:1525-1530. [DOI: 10.1021/acs.jpca.6b12691] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Thomas Simonson
- Laboratoire
de Biochimie (CNRS UMR7654), Ecole Polytechnique, 91128 Palaiseau, France
| | - Gerhard Hummer
- Department
of Theoretical Biophysics, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
- Institute
of Biophysics, Goethe-University Frankfurt, 60438 Frankfurt
am Main, Germany
| | - Benoît Roux
- Department
of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637, United States
- Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
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30
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Effect of Sodium and Chloride Binding on a Lecithin Bilayer. A Molecular Dynamics Study. MEMBRANES 2017; 7:membranes7010005. [PMID: 28125062 PMCID: PMC5371966 DOI: 10.3390/membranes7010005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 01/12/2017] [Accepted: 01/14/2017] [Indexed: 01/17/2023]
Abstract
The effect of ion binding on the structural, mechanical, dynamic and electrostatic properties of a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) bilayer in a 0.5 M aqueous NaCl solution is investigated using classical atomistic molecular dynamics simulation with different force-field descriptions for ion-ion and ion-lipid interactions. Most importantly, the repulsive Lennard-Jones parameters for the latter were modified, such that approximately similar binding of cations and anions to the lipid membrane is achieved. This was done to qualitatively improve the apparent ion-lipid binding constants obtained from simulations with the original force field (Berger lipids and GROMOS87 ions in combination with the SPC water model) in comparison to experimental data. Furthermore, various parameters characterizing membrane structure, elasticity, order and dynamics are analyzed. It is found that ion binding as observed in simulations involving the modified in comparison to the original force-field description leads to: (i) a smaller salt-induced change in the area per lipid, which is in closer agreement with the experiment; (ii) a decrease in the area compressibility and bilayer thickness to values comparable to a bilayer in pure water; (iii) lipid deuterium order parameters and lipid diffusion coefficients on nanosecond timescales that are very similar to the values for a membrane in pure water. In general, salt effects on the structural properties of a POPC bilayer in an aqueous sodium-chloride solution appear to be reproduced reasonably well by the new force-field description. An analysis of membrane-membrane disjoining pressure suggests that the smaller salt-induced change in area per lipid induced by the new force-field description is not due to the alteration of membrane-associated net charge, but must rather be understood as a consequence of ion-specific effects on the arrangement of lipid molecules.
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31
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Borges NM, Kenny PW, Montanari CA, Prokopczyk IM, Ribeiro JFR, Rocha JR, Sartori GR. The influence of hydrogen bonding on partition coefficients. J Comput Aided Mol Des 2017; 31:163-181. [PMID: 28054187 DOI: 10.1007/s10822-016-0002-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 12/16/2016] [Indexed: 11/28/2022]
Abstract
This Perspective explores how consideration of hydrogen bonding can be used to both predict and better understand partition coefficients. It is shown how polarity of both compounds and substructures can be estimated from measured alkane/water partition coefficients. When polarity is defined in this manner, hydrogen bond donors are typically less polar than hydrogen bond acceptors. Analysis of alkane/water partition coefficients in conjunction with molecular electrostatic potential calculations suggests that aromatic chloro substituents may be less lipophilic than is generally believed and that some of the effect of chloro-substitution stems from making the aromatic π-cloud less available to hydrogen bond donors. Relationships between polarity and calculated hydrogen bond basicity are derived for aromatic nitrogen and carbonyl oxygen. Aligned hydrogen bond acceptors appear to present special challenges for prediction of alkane/water partition coefficients and this may reflect 'frustration' of solvation resulting from overlapping hydration spheres. It is also shown how calculated hydrogen bond basicity can be used to model the effect of aromatic aza-substitution on octanol/water partition coefficients.
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Affiliation(s)
- Nádia Melo Borges
- Grupo de Estudos em Química Medicinal - NEQUIMED, Instituto de Química de São Carlos - Universidade de São Paulo, Av. Trabalhador Sancarlense, 400, São Carlos, SP, 13566-590, Brazil
| | - Peter W Kenny
- Grupo de Estudos em Química Medicinal - NEQUIMED, Instituto de Química de São Carlos - Universidade de São Paulo, Av. Trabalhador Sancarlense, 400, São Carlos, SP, 13566-590, Brazil.
| | - Carlos A Montanari
- Grupo de Estudos em Química Medicinal - NEQUIMED, Instituto de Química de São Carlos - Universidade de São Paulo, Av. Trabalhador Sancarlense, 400, São Carlos, SP, 13566-590, Brazil
| | - Igor M Prokopczyk
- Grupo de Estudos em Química Medicinal - NEQUIMED, Instituto de Química de São Carlos - Universidade de São Paulo, Av. Trabalhador Sancarlense, 400, São Carlos, SP, 13566-590, Brazil
| | - Jean F R Ribeiro
- Grupo de Estudos em Química Medicinal - NEQUIMED, Instituto de Química de São Carlos - Universidade de São Paulo, Av. Trabalhador Sancarlense, 400, São Carlos, SP, 13566-590, Brazil
| | - Josmar R Rocha
- Grupo de Estudos em Química Medicinal - NEQUIMED, Instituto de Química de São Carlos - Universidade de São Paulo, Av. Trabalhador Sancarlense, 400, São Carlos, SP, 13566-590, Brazil
| | - Geraldo Rodrigues Sartori
- Grupo de Estudos em Química Medicinal - NEQUIMED, Instituto de Química de São Carlos - Universidade de São Paulo, Av. Trabalhador Sancarlense, 400, São Carlos, SP, 13566-590, Brazil
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32
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Izadi S, Onufriev AV. Accuracy limit of rigid 3-point water models. J Chem Phys 2016; 145:074501. [PMID: 27544113 PMCID: PMC4991989 DOI: 10.1063/1.4960175] [Citation(s) in RCA: 167] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 07/19/2016] [Indexed: 11/14/2022] Open
Abstract
Classical 3-point rigid water models are most widely used due to their computational efficiency. Recently, we introduced a new approach to constructing classical rigid water models [S. Izadi et al., J. Phys. Chem. Lett. 5, 3863 (2014)], which permits a virtually exhaustive search for globally optimal model parameters in the sub-space that is most relevant to the electrostatic properties of the water molecule in liquid phase. Here we apply the approach to develop a 3-point Optimal Point Charge (OPC3) water model. OPC3 is significantly more accurate than the commonly used water models of same class (TIP3P and SPCE) in reproducing a comprehensive set of liquid bulk properties, over a wide range of temperatures. Beyond bulk properties, we show that OPC3 predicts the intrinsic charge hydration asymmetry (CHA) of water - a characteristic dependence of hydration free energy on the sign of the solute charge - in very close agreement with experiment. Two other recent 3-point rigid water models, TIP3PFB and H2ODC, each developed by its own, completely different optimization method, approach the global accuracy optimum represented by OPC3 in both the parameter space and accuracy of bulk properties. Thus, we argue that an accuracy limit of practical 3-point rigid non-polarizable models has effectively been reached; remaining accuracy issues are discussed.
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Affiliation(s)
- Saeed Izadi
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia 24060, USA
| | - Alexey V Onufriev
- Departments of Computer Science and Physics, Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, Virginia 24060, USA
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33
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Horta BAC, Merz PT, Fuchs PFJ, Dolenc J, Riniker S, Hünenberger PH. A GROMOS-Compatible Force Field for Small Organic Molecules in the Condensed Phase: The 2016H66 Parameter Set. J Chem Theory Comput 2016; 12:3825-50. [DOI: 10.1021/acs.jctc.6b00187] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bruno A. C. Horta
- Laboratory
of Physical Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland
- Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-909, Brazil
| | - Pascal T. Merz
- Laboratory
of Physical Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Patrick F. J. Fuchs
- Institut Jacques Monod, UMR 7592 CNRS, Université Paris-Diderot, Sorbonne Paris Cité, F-75205 Paris, France
| | - Jozica Dolenc
- Laboratory
of Physical Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland
- Chemistry,
Biology and Pharmacy Information Center, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Sereina Riniker
- Laboratory
of Physical Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland
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