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Bardaud JX, Hayakawa Y, Takayanagi H, Hirata K, Ishiuchi SI, Fujii M, Gloaguen E. Water-Induced Dissociative Mechanism of Carboxylate and Divalent Calcium Ions Revealed by IR Laser Spectroscopy. J Phys Chem Lett 2024:9295-9300. [PMID: 39235303 DOI: 10.1021/acs.jpclett.4c01803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2024]
Abstract
The dissociation of carboxylate and divalent calcium ions is investigated at the molecular level in microsolvation experiments by gradually increasing the number of water molecules around the ions. IR photodissociation (IRPD) laser spectroscopy of H2-tagged (Ca2+, AcO-)(H2O)n=8-21 clusters in the ν(CO2-) spectral range combined with RI-B97-D3-BJ-abc/TZVPPD frequency calculations is used to identify the type of ion pairs involved in this process. These results reveal that the ion dissociation follows a multistep mechanism involving in particular pseudobridged monodentate contact ion pairs (CIPs), which are found to be the first intermediate species formed from bidentate CIPs along the ion dissociation path. Altogether, structural assignments suggest a sequence of simple reactions in the first coordination shell of the carboxylate group, leading us to propose two possible dissociation paths. The appearance threshold of monodentate structures is measured at n = 10, with that of solvent-shared ion pairs (SIPs) being potentially at n = 18. By showing in detail how solvation progressively takes over from the ionic interaction in shaping these supramolecular structures, this study can serve as a reference for solving ion-pairing/dissociation problems.
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Affiliation(s)
- Jean-Xavier Bardaud
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91400 Orsay, France
| | - Yurika Hayakawa
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Hikaru Takayanagi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
| | - Keisuke Hirata
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
| | - Shun-Ichi Ishiuchi
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- IRFI/IPWR, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
| | - Masaaki Fujii
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
- IRFI/IPWR, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- Research and Development Initiative, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan
| | - Eric Gloaguen
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91400 Orsay, France
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Clark JA, Douglas JF. Do Specific Ion Effects on Collective Relaxation Arise from Perturbation of Hydrogen-Bonding Network Structure? J Phys Chem B 2024; 128:6362-6375. [PMID: 38912895 PMCID: PMC11229691 DOI: 10.1021/acs.jpcb.4c02638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 06/07/2024] [Accepted: 06/10/2024] [Indexed: 06/25/2024]
Abstract
The change in the transport properties (i.e., water diffusivity, shear viscosity, etc.) when adding salts to water has been used to classify ions as either being chaotropic or kosmotropic, a terminology based on the presumption that this phenomenon arises from respective breakdown or enhancement of the hydrogen-bonding network structure. Recent quasi-elastic neutron scattering measurements of the collective structural relaxation time, τC, in aqueous salt solutions were interpreted as confirming this proposed origin of ion effects on the dynamics of water. However, we find similar changes in τC in the same salt solutions based on molecular dynamics (MD) simulations using a coarse-grained water model in which no hydrogen bonding exists, challenging this conventional interpretation of mobility change resulting from the addition of salts to water. A thorough understanding of specific ion effects should be useful in diverse material manufacturing and biomedical applications, where these effects are prevalent, but poorly understood.
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Affiliation(s)
- Jennifer A. Clark
- Materials Science and Engineering
Division, Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | - Jack F. Douglas
- Materials Science and Engineering
Division, Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
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3
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Posey AE, Bremer A, Erkamp NA, Pant A, Knowles TPJ, Dai Y, Mittag T, Pappu RV. Biomolecular condensates are characterized by interphase electric potentials. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.02.601783. [PMID: 39005320 PMCID: PMC11245003 DOI: 10.1101/2024.07.02.601783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Biomolecular condensates form via processes that combine phase separation and reversible associations of multivalent macromolecules. Condensates can be two- or multi-phase systems defined by coexisting dense and dilute phases. Here, we show that solution ions can partition asymmetrically across coexisting phases defined by condensates formed by intrinsically disordered proteins or homopolymeric RNA molecules. Our findings were enabled by direct measurements of the activities of cations and anions within coexisting phases of protein and RNA condensates. Asymmetries in ion partitioning between coexisting phases vary with protein sequence, condensate type, salt concentration, and ion type. The Donnan equilibrium set up by asymmetrical partitioning of solution ions generates interphase electric potentials known as Donnan and Nernst potentials. Our measurements show that the interphase potentials of condensates are of the same order of magnitude as membrane potentials of membrane-bound organelles. Interphase potentials quantify the degree to which microenvironments of coexisting phases are different from one another. Importantly, and based on condensate-specific interphase electric potentials, which are membrane-like potentials of membraneless bodies, we reason that condensates are mesoscale capacitors that store charge. Interphase potentials lead to electric double layers at condensate interfaces. This helps explain recent observations of condensate interfaces being electrochemically active.
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4
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Raji F, Nguyen NN, Nguyen CV, Nguyen AV. Lead (II) ions enable the ion-specific effects of monovalent anions on the molecular structure and interactions at silica/aqueous interfaces. J Colloid Interface Sci 2024; 662:653-662. [PMID: 38367582 DOI: 10.1016/j.jcis.2024.02.094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 02/07/2024] [Accepted: 02/11/2024] [Indexed: 02/19/2024]
Abstract
HYPOTHESIS The adsorption of heavy metal ions such as Pb(II) onto negatively charged minerals such as silica is expected to alter the structure and the interactions at the silica/aqueous interfaces. Besides the solution pH, the inner-sphere sorption of Pb(II) is expected to regulate the surface charge/potential, hypothesized to control the actions of monovalent anions in the aqueous environment. These complex pictures can be probed directly using surface-sensitive sum-frequency generation (SFG) spectroscopy. EXPERIMENTS The pH-dependent water structure within the double layer at silica/aqueous interfaces under the influence of different ions was examined using SFG. The recorded SFG spectra were deconvoluted into the Stern layer (SL) and diffuse layer (DL) using the maximum entropy method in conjunction with the electrical double-layer theory. FINDINGS Standalone monovalent sodium salts do not exhibit ion-specific effects on the silica/aqueous interfaces. However, the mixture of Pb(II) species and each of these salts display profound ion-specific effects on the structure of silica/aqueous interfaces, indicating the role of Pb(II) as an enabler of the ion-specificity of the investigated monovalent anions. The interesting effect arises from a complex interplay between the physical processes (i.e., electrostatic interactions, screening effects, etc.) and chemical processes such as the hydrolysis of Pb(II) ions, ion complexation, protonation and deprotonation of the surface silanol group.
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Affiliation(s)
- Foad Raji
- School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia.
| | - Ngoc N Nguyen
- School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Cuong V Nguyen
- Department of Water and Environmental Regulation, Joondalup, WA 6027, Australia
| | - Anh V Nguyen
- School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
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5
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Pouliquen DL. The biophysics of water in cell biology: perspectives on a keystone for both marine sciences and cancer research. Front Cell Dev Biol 2024; 12:1403037. [PMID: 38803391 PMCID: PMC11128620 DOI: 10.3389/fcell.2024.1403037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 04/29/2024] [Indexed: 05/29/2024] Open
Abstract
The biophysics of water, has been debated over more than a century. Although its importance is still underestimated, significant breakthroughs occurred in recent years. The influence of protein condensation on water availability control was documented, new findings on water-transport proteins emerged, and the way water molecules rearrange to minimize free energy at interfaces was deciphered, influencing membrane thermodynamics. The state of knowledge continued to progress in the field of deep-sea marine biology, highlighting unknown effects of high hydrostatic pressure and/or temperature on interactions between proteins and ligands in extreme environments, and membrane structure adaptations. The role of osmolytes in protein stability control under stress is also discussed here in relation to fish egg hydration/buoyancy. The complexity of water movements within the cell is updated, all these findings leading to a better view of their impact on many cellular processes. The way water flow and osmotic gradients generated by ion transport work together to produce the driving force behind cell migration is also relevant to both marine biology and cancer research. Additional common points concern water dynamic changes during the neoplastic transformation of cells and tissues, or embryo development. This could improve imaging techniques, early cancer diagnosis, and understanding of the molecular and physiological basis of buoyancy for many marine species.
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Affiliation(s)
- Daniel L. Pouliquen
- Inserm, CNRS, CRCINA, Nantes Université, University of Angers, Angers, France
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6
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Jindal A, Schienbein P, Marx D. Revealing the Molecular Origin of Anisotropy around Chloride Ions in Bulk Water. J Phys Chem Lett 2024; 15:3037-3042. [PMID: 38466241 DOI: 10.1021/acs.jpclett.3c03585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
A clear picture of the local solvation structure around halide anions in liquid water remains elusive. This discussion has been stimulated by pioneering simulation results that proposed a "hydrophobic cavity" around anions in the bulk, which is analogous to air at the air-water interface. However, there is also sound experimental and theoretical evidence that halide ions are rather symmetrically solvated in the bulk, leading to a different viewpoint. Using extensive ab initio molecular dynamics simulations of an aqueous Cl- solution, we indeed find an anisotropic arrangement of H-bonded versus interstitial water molecules. The latter are not H-bonded to the anions and thus do not couple much electronically to Cl-. The resulting purely electronic anisotropy of the local solvation environment correlates with that structural anisotropy, which however should not be understood as an empty cavity─as it would be at the air-water interface─but rather contains interstitial water molecules.
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Affiliation(s)
- Aman Jindal
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Philipp Schienbein
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
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7
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G Lopez C, Matsumoto A, Shen AQ. Dilute polyelectrolyte solutions: recent progress and open questions. SOFT MATTER 2024; 20:2635-2687. [PMID: 38427030 DOI: 10.1039/d3sm00468f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Polyelectrolytes are a class of polymers possessing ionic groups on their repeating units. Since counterions can dissociate from the polymer backbone, polyelectrolyte chains are strongly influenced by electrostatic interactions. As a result, the physical properties of polyelectrolyte solutions are significantly different from those of electrically neutral polymers. The aim of this article is to highlight key results and some outstanding questions in the polyelectrolyte research from recent literature. We focus on the influence of electrostatics on conformational and hydrodynamic properties of polyelectrolyte chains. A compilation of experimental results from the literature reveals significant disparities with theoretical predictions. We also discuss a new class of polyelectrolytes called poly(ionic liquid)s that exhibit unique physical properties in comparison to ordinary polyelectrolytes. We conclude this review by listing some key research challenges in order to fully understand the conformation and dynamics of polyelectrolytes in solutions.
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Affiliation(s)
- Carlos G Lopez
- Institute of Physical Chemistry, RWTH Aachen University, Aachen, 52056, Germany
| | - Atsushi Matsumoto
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui City, Fukui 910-8507, Japan.
| | - Amy Q Shen
- Micro/Bio/Nanofluidics Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan.
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8
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Wongphattarakul S, Kuson R, Sastraruji T, Suttiat K. Fluoride Release and Rechargeability of Poly(lactic acid) Composites with Glass Ionomer Cement. Polymers (Basel) 2023; 15:4041. [PMID: 37896284 PMCID: PMC10609893 DOI: 10.3390/polym15204041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 10/02/2023] [Accepted: 10/02/2023] [Indexed: 10/29/2023] Open
Abstract
This study investigates the fluoride release, rechargeability and degradation behaviors of newly developed anticariogenic poly(lactic acid) (PLA) composites. The PLA composite with various concentrations (0%, 5%, 10%, 15% and 20% by weight) of glass ionomer cement (GIC) and sodium fluoride (NaF) were prepared using solvent casting method. The fluoride release, fluoride rechargeability and degradation behavior were evaluated. All experimental groups demonstrated fluoride-releasing ability. The highest level of fluoride ions released was found in PLA composite with sodium fluoride (PLA/NaF). Following the 28-day period, both groups showed a gradual reduction in fluoride ion released, ranging between 0.03 ± 0.01 and 0.53 ± 0.06 ppm, although remaining within the effective range for tooth remineralization. However, the rechargeability was only observed in PLA composite with GIC (PLA/GIC). Following an eight-week in vitro degradation test, all PLA/NaF groups displayed a significantly higher percentage of weight change and water absorption compared to the PLA/GIC and the control group. In SEM analysis, the formation of surface porosities was clearly noticed in all PLA/NaF. All specimens retained their structural integrity throughout the study. In conclusion, the newly developed PLA/GIC displays promising possibilities as an anticariogenic material. Furthermore, the rechargeability of these ions are repeatable, ensuring their long-term utility.
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Affiliation(s)
- Sudarat Wongphattarakul
- Department of Prosthodontics, Faculty of Dentistry, Chiang Mai University, Chiang Mai 50200, Thailand; (S.W.); (R.K.)
| | - Rungroj Kuson
- Department of Prosthodontics, Faculty of Dentistry, Chiang Mai University, Chiang Mai 50200, Thailand; (S.W.); (R.K.)
| | - Thanapat Sastraruji
- Dental Research Center, Faculty of Dentistry, Chiang Mai University, Chiang Mai 50200, Thailand;
| | - Kullapop Suttiat
- Department of Prosthodontics, Faculty of Dentistry, Chiang Mai University, Chiang Mai 50200, Thailand; (S.W.); (R.K.)
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9
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Herman CE, Valiya Parambathu A, Asthagiri DN, Lenhoff AM. Polarizability Plays a Decisive Role in Modulating Association between Molecular Cations and Anions. J Phys Chem Lett 2023; 14:7020-7026. [PMID: 37523856 DOI: 10.1021/acs.jpclett.3c01566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Electrostatic interactions involving proteins depend on not only the ionic charges involved but also their chemical identities. Here we examine the origins of incompletely understood differences in the strength of association of different pairs of monovalent molecular ions that are relevant to protein-protein and protein-ligand interactions. Cationic analogues of the basic amino acid side chains are simulated, along with oxyanionic analogues of cation-exchange ligands and acidic amino acids. Experimentally observed association trends with respect to the cations, but not anions, are captured by a nonpolarizable model. An effective continuum correction to account for electronic polarizability can capture both trends better but at the expense of fidelity to the underlying free energy landscape for ion-pair association. A polarizable model proves decisive in capturing experimentally suggested trends with respect to both cations and anions; critically, the free energy landscape for ion-pair association is itself altered, thus altering configurational sampling.
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Affiliation(s)
- Chase E Herman
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, Delaware 19716, United States
| | - Arjun Valiya Parambathu
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, Delaware 19716, United States
| | - Dilipkumar N Asthagiri
- Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37830, United States
| | - Abraham M Lenhoff
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, Delaware 19716, United States
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10
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Bañuelos JL, Borguet E, Brown GE, Cygan RT, DeYoreo JJ, Dove PM, Gaigeot MP, Geiger FM, Gibbs JM, Grassian VH, Ilgen AG, Jun YS, Kabengi N, Katz L, Kubicki JD, Lützenkirchen J, Putnis CV, Remsing RC, Rosso KM, Rother G, Sulpizi M, Villalobos M, Zhang H. Oxide- and Silicate-Water Interfaces and Their Roles in Technology and the Environment. Chem Rev 2023; 123:6413-6544. [PMID: 37186959 DOI: 10.1021/acs.chemrev.2c00130] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Interfacial reactions drive all elemental cycling on Earth and play pivotal roles in human activities such as agriculture, water purification, energy production and storage, environmental contaminant remediation, and nuclear waste repository management. The onset of the 21st century marked the beginning of a more detailed understanding of mineral aqueous interfaces enabled by advances in techniques that use tunable high-flux focused ultrafast laser and X-ray sources to provide near-atomic measurement resolution, as well as by nanofabrication approaches that enable transmission electron microscopy in a liquid cell. This leap into atomic- and nanometer-scale measurements has uncovered scale-dependent phenomena whose reaction thermodynamics, kinetics, and pathways deviate from previous observations made on larger systems. A second key advance is new experimental evidence for what scientists hypothesized but could not test previously, namely, interfacial chemical reactions are frequently driven by "anomalies" or "non-idealities" such as defects, nanoconfinement, and other nontypical chemical structures. Third, progress in computational chemistry has yielded new insights that allow a move beyond simple schematics, leading to a molecular model of these complex interfaces. In combination with surface-sensitive measurements, we have gained knowledge of the interfacial structure and dynamics, including the underlying solid surface and the immediately adjacent water and aqueous ions, enabling a better definition of what constitutes the oxide- and silicate-water interfaces. This critical review discusses how science progresses from understanding ideal solid-water interfaces to more realistic systems, focusing on accomplishments in the last 20 years and identifying challenges and future opportunities for the community to address. We anticipate that the next 20 years will focus on understanding and predicting dynamic transient and reactive structures over greater spatial and temporal ranges as well as systems of greater structural and chemical complexity. Closer collaborations of theoretical and experimental experts across disciplines will continue to be critical to achieving this great aspiration.
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Affiliation(s)
- José Leobardo Bañuelos
- Department of Physics, The University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Eric Borguet
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Gordon E Brown
- Department of Earth and Planetary Sciences, The Stanford Doerr School of Sustainability, Stanford University, Stanford, California 94305, United States
| | - Randall T Cygan
- Department of Soil and Crop Sciences, Texas A&M University, College Station, Texas 77843, United States
| | - James J DeYoreo
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Patricia M Dove
- Department of Geosciences, Department of Chemistry, Department of Materials Science and Engineering, Virginia Tech, Blacksburg, Virginia 24060, United States
| | - Marie-Pierre Gaigeot
- Université Paris-Saclay, Univ Evry, CNRS, LAMBE UMR8587, 91025 Evry-Courcouronnes, France
| | - Franz M Geiger
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Julianne M Gibbs
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2Canada
| | - Vicki H Grassian
- Department of Chemistry and Biochemistry, University of California, San Diego, California 92093, United States
| | - Anastasia G Ilgen
- Geochemistry Department, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Young-Shin Jun
- Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Nadine Kabengi
- Department of Geosciences, Georgia State University, Atlanta, Georgia 30303, United States
| | - Lynn Katz
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - James D Kubicki
- Department of Earth, Environmental & Resource Sciences, The University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Johannes Lützenkirchen
- Karlsruher Institut für Technologie (KIT), Institut für Nukleare Entsorgung─INE, Eggenstein-Leopoldshafen 76344, Germany
| | - Christine V Putnis
- Institute for Mineralogy, University of Münster, Münster D-48149, Germany
| | - Richard C Remsing
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Kevin M Rosso
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Gernot Rother
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Marialore Sulpizi
- Department of Physics, Ruhr Universität Bochum, NB6, 65, 44780, Bochum, Germany
| | - Mario Villalobos
- Departamento de Ciencias Ambientales y del Suelo, LANGEM, Instituto De Geología, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Huichun Zhang
- Department of Civil and Environmental Engineering, Case Western Reserve University, Cleveland, Ohio 44106, United States
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11
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Reynolds JG. Zavitsas’ model of aqueous NaF solution activities utilizing hydration numbers reported from Dielectric Relaxation spectroscopy. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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12
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N.Kobrak M, Nykypanchuk D, H C. Janssen C. Protic Amine/Acid Mixtures as Solvents for the Extraction of Aqueous Zinc Salts: A Mechanistic Study. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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13
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Gao A, Remsing RC, Weeks JD. Local Molecular Field Theory for Coulomb Interactions in Aqueous Solutions. J Phys Chem B 2023; 127:809-821. [PMID: 36669139 DOI: 10.1021/acs.jpcb.2c06988] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Coulomb interactions play a crucial role in a wide array of processes in aqueous solutions but present conceptual and computational challenges to both theory and simulations. We review recent developments in an approach addressing these challenges─local molecular field (LMF) theory. LMF theory exploits an exact and physically suggestive separation of intermolecular Coulomb interactions into strong short-range and uniformly slowly varying long-range components. This allows us to accurately determine the averaged effects of the long-range components on the short-range structure using effective single particle fields and analytical corrections, greatly reducing the need for complex lattice summation techniques used in most standard approaches. The simplest use of these ideas in aqueous solutions leads to the short solvent (SS) model, where both solvent-solvent and solute-solvent Coulomb interactions have only short-range components. Here we use the SS model to give a simple description of pairing of nucleobases and biologically relevant ions in water.
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Affiliation(s)
- Ang Gao
- Department of Physics, Beijing University of Posts and Telecommunications, Beijing, China 100876
| | - Richard C Remsing
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States
| | - John D Weeks
- Institute for Physical Science and Technology and Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
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14
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Hegaard F, Biro R, Ehtiati K, Thormann E. Ion-Specific Antipolyelectrolyte Effect on the Swelling Behavior of Polyzwitterionic Layers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:1456-1464. [PMID: 36656651 DOI: 10.1021/acs.langmuir.2c02798] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
In this study, we systematically investigate the interactions between mobile ions generated from added salts and immobile charges within a sulfobetaine-based polyzwitterionic film in the presence of five salts (KCl, KBr, KSCN, LiCl, and CsCl). The sulfobetaine groups contain quaternary alkylammonium and sulfonate groups, giving the positive and negative charges. The swelling of the zwitterionic film in the presence of different salts is compared with the swelling behavior of a polycationic or polyanionic film containing the same charged groups. For such a comparative study, we design cross-linked terpolymer films with similar thicknesses, cross-link densities, and charge fractions, but with varying charged moieties. While the addition of salt in general leads to a collapse of both cationic and anionic films, the presence of specific types of mobile anions (Cl-, Br-, and SCN-) considerably influences the swelling behavior of polycationic films. We attribute this observation to a different degree of ion-pair formations between the different types of anionic counterions and the immobile cationic quaternary alkylammonium groups in the films where highly polarizable counterions such as SCN- lead to a high degree of ion pairing and less polarizable counterions, such as Cl-, cause a low degree of ion pairing. Conversely, we do not observe any substantial effect of varying the type of cationic counterions (K+, Li+, and Cs+), which we assign to the lack of ion pairing between the weakly polarizable cations and the immobile anionic sulfonate groups in the films. In addition, we observe that the zwitterionic films swell with increasing ionic strength and the degree of swelling is anion dependent, which is in agreement with previous reports on the "antipolyelectrolyte effect". Herein, we explain this ion-specific swelling behavior with the different cation and anion abilities to form ion pairs with quaternary alkylammonium and sulfonate in the sulfobetaine groups.
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Affiliation(s)
- Frederik Hegaard
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Robert Biro
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Koosha Ehtiati
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Esben Thormann
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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15
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Toussaint B, Immame Hassane Beck T, Surget E, Boudy V, Jaccoulet E. Exploration of the effects of chloride ions on the analysis of polar compounds at low concentrations by hydrophilic interaction liquid chromatography coupled to a charged aerosol detector: Application to tromethamine. J Sep Sci 2023; 46:e2200766. [PMID: 36621867 DOI: 10.1002/jssc.202200766] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/24/2022] [Accepted: 12/26/2022] [Indexed: 01/10/2023]
Abstract
In this study, we discuss the origin of the slightly increased response of the charged aerosol detector when low-concentration polar drugs formulated with sodium chloride are analyzed by hydrophilic interaction liquid chromatography coupled to the charged aerosol detector. In the case of tromethamine mixed with saline solutions, we investigated several levels including the mobile phase, sample matrix, and detection. We show that the analysis of the rich-salted sample results in both interactions with the mobile phase modifiers and the stationary phase during the run time. With 150 mM NaCl as a compounding solution, a slight increase in the tromethamine peak area was observed (<5.5%). Our study suggests that chloride ions in excess sequentially interact firstly with the counterions from the organic modifiers and secondly with the analyte via the stationary phase and the contribution of hydrophilic interaction liquid chromatography retention mechanisms. Because of these effects, the hydrophilic interaction liquid chromatography-charged aerosol detector analysis of drugs in saline solutions requires particular attention, and a correction factor for quantitative purposes that accounts for formulation ions remains appropriate.
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Affiliation(s)
- Balthazar Toussaint
- Département recherche et développement pharmaceutique, Etablissement pharmaceutique, Agence générale des équipements et produits de santé, AP-HP, Paris, France.,Université de Paris Cité, CNRS, INSERM, UTCBS, Unité de Technologies Chimiques et Biologiques pour la santé, Faculté de Pharmacie, F-75006, Paris, France
| | - Taslyne Immame Hassane Beck
- Département recherche et développement pharmaceutique, Etablissement pharmaceutique, Agence générale des équipements et produits de santé, AP-HP, Paris, France
| | - Estelle Surget
- Département recherche et développement pharmaceutique, Etablissement pharmaceutique, Agence générale des équipements et produits de santé, AP-HP, Paris, France
| | - Vincent Boudy
- Département recherche et développement pharmaceutique, Etablissement pharmaceutique, Agence générale des équipements et produits de santé, AP-HP, Paris, France.,Université de Paris Cité, CNRS, INSERM, UTCBS, Unité de Technologies Chimiques et Biologiques pour la santé, Faculté de Pharmacie, F-75006, Paris, France
| | - Emmanuel Jaccoulet
- Département recherche et développement pharmaceutique, Etablissement pharmaceutique, Agence générale des équipements et produits de santé, AP-HP, Paris, France
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16
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Separation of phosphorothioate oligonucleotide impurities by WAX HPLC under high organic content elution conditions. Anal Biochem 2022; 659:114956. [PMID: 36270331 DOI: 10.1016/j.ab.2022.114956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 10/11/2022] [Accepted: 10/12/2022] [Indexed: 12/14/2022]
Abstract
The separation of impurities in phosphorothioate diester (PS) oligonucleotides is complicated by (1) the presence of a very large number of diastereoisomers, e.g., 219 for a 20-mer oligonucleotide, (2) peak broadening due to the hydrophobic character of the sulfur atom, and (3) the chemical similarity of the impurities to the parent oligonucleotide and each other. Further difficulties arise due to the chemical nature of oligonucleotides, which display a complex mixture of ionic, hydrophobic, H-bonding, and other functionalities. To minimize hydrophobic interactions and peak broadening due to the PS modification, we have developed a novel method that combines a weak anion exchange (WAX) column with a mobile phase elution system designed to maximize separation by a single ionic/electrostatic interaction. We found that although chaotropes are helpful, the most significant beneficial effect of the hydrophilic WAX column is that high-organic, low-salt mobile phase is required for product elution. Separations are also benefitted by pH gradient effects on stationary phase electrostatic potential and analyte ionization. An extraordinary degree of separation is achieved by the new WAX method in comparison to SAX (strong anion exchange) chromatography. For the first time, the extent of deamination of PS oligonucleotides is directly determined by a chromatography-only method. The approach, representative results, and the mechanisms of separation are discussed.
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17
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Acar M, Tatini D, Ninham BW, Rossi F, Marchettini N, Lo Nostro P. The Lyotropic Nature of Halates: An Experimental Study. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238519. [PMID: 36500616 PMCID: PMC9739596 DOI: 10.3390/molecules27238519] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/24/2022] [Accepted: 11/25/2022] [Indexed: 12/12/2022]
Abstract
Unlike halides, where the kosmotropicity decreases from fluoride to iodide, the kosmotropic nature of halates apparently increases from chlorate to iodate, in spite of the lowering in the static ionic polarizability. In this paper, we present an experimental study that confirms the results of previous simulations. The lyotropic nature of aqueous solutions of sodium halates, i.e., NaClO3, NaBrO3, and NaIO3, is investigated through density, conductivity, viscosity, and refractive index measurements as a function of temperature and salt concentration. From the experimental data, we evaluate the activity coefficients and the salt polarizability and assess the anions' nature in terms of kosmotropicity/chaotropicity. The results clearly indicate that iodate behaves as a kosmotrope, while chlorate is a chaotrope, and bromate shows an intermediate nature. This experimental study confirms that, in the case of halates XO3-, the kosmotropic-chaotropic ranking reverses with respect to halides. We also discuss and revisit the role of the anion's polarizability in the interpretation of Hofmeister phenomena.
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Affiliation(s)
- Mert Acar
- Department of Chemistry “Ugo Schiff” and CSGI, University of Florence, 50019 Firenze, Italy
| | - Duccio Tatini
- Department of Chemistry “Ugo Schiff” and CSGI, University of Florence, 50019 Firenze, Italy
| | - Barry W. Ninham
- Materials Physics (Formerly Department of Applied Mathematics), Research School of Physics, Australian National University, Canberra, ACT 2600, Australia
- School of Science, University of New South Wales, Northcott Drive, Campbell, Canberra, ACT 2612, Australia
| | - Federico Rossi
- Department of Earth, Environmental and Physical Sciences, University of Siena, 53100 Siena, Italy
| | - Nadia Marchettini
- Department of Earth, Environmental and Physical Sciences, University of Siena, 53100 Siena, Italy
| | - Pierandrea Lo Nostro
- Department of Chemistry “Ugo Schiff” and CSGI, University of Florence, 50019 Firenze, Italy
- Correspondence: ; Tel.: +39-055-4573010
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18
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Beri D, Budiman S, Sudiar NY, Yusra A, Erianjoni E, Ganefri G, Amran A. Fabrication of ballpoint-ink via encapsulating inorganic pigments in microemulsion gels. RSC Adv 2022; 12:24640-24646. [PMID: 36128370 PMCID: PMC9426292 DOI: 10.1039/d2ra04463c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 08/19/2022] [Indexed: 11/21/2022] Open
Abstract
The fabrication of ballpoint-ink might open up a new perspective on physico-chemical solubility thermodynamics. In this report, we present a method to encapsulate inorganic pigments, such as Fe(CNS)3 (red), Fe2Fe(CN)6 (blue), CdS (yellow), and CuS (black) into w/o microemulsion gels. The area of w/o microemulsions was first determined by titrating surfactants Tween-60 into the given composition of water and cyclohexane in the pseudo-three phase diagram. Three prosperous phase areas were successfully mapped using this method, namely: microemulsion (w/o, and o/w) or (μE), lamellar liquid crystal (Lα), and hexagonal liquid crystal (Hα), respectively. The results show that inorganic pigments were well soluble in the w/o microemulsion gel of the Tween-60/cyclohexane/water system. The highest solubility of inorganic pigments in the microemulsion gel is 3.63 ± 0.05 mg g-1 for the red pigment of Fe(CNS)3, and the lowest is 2.92 ± 0.05 mg g-1 for the yellow pigment of CdS. Hence, the solubility limit distribution for all pigments is 2.9 ± 0.05 <>3.63 ± 0.05 mg g-1. The cation and anion size strongly affected the inorganic pigments' solubility in the w/o-microemulsion system. Some quantity of the ink-made of inorganic pigments encapsulated in the microemulsion gel has been inserted into empty ballpoint sleeves as prototypes. The resulting self-made inks demonstrated that the physical appearances of the ink could mimic the factory-made inks. Nevertheless, the self-made ink should be investigated further for long lifespan use, especially for long-term stability and corrosion resistance.
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Affiliation(s)
- Deski Beri
- Chemistry Department, Faculty of Mathematics and Science, Universitas Negeri Padang Jl. Hamka, Air Tawar Padang Indonesia 25132
| | - Septian Budiman
- Chemistry Department, Faculty of Mathematics and Science, Universitas Negeri Padang Jl. Hamka, Air Tawar Padang Indonesia 25132
| | - Nofi Yendri Sudiar
- Physics Department, Faculty of Mathematics and Science, Universitas Negeri Padang Jl. Hamka, Air Tawar Padang Indonesia 25132
| | - Alfajri Yusra
- Sociology Department, Faculty of Social Science, Universitas Negeri Padang Jl. Hamka, Air Tawar Padang Indonesia 25132
| | - Erianjoni Erianjoni
- Sociology Department, Faculty of Social Science, Universitas Negeri Padang Jl. Hamka, Air Tawar Padang Indonesia 25132
| | - Ganefri Ganefri
- Electrical Engineering Department, Faculty of Engineering, Universitas Negeri Padang Jl. Hamka, Air Tawar Padang Indonesia 25132
| | - Ali Amran
- Chemistry Department, Faculty of Mathematics and Science, Universitas Negeri Padang Jl. Hamka, Air Tawar Padang Indonesia 25132
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19
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Chialvo AA. Molecular-Based Description of the Osmotic Second Virial Coefficients of Electrolytes: Rigorous Formal Links to Solute-Solvent Interaction Asymmetry, Virial Expansion Paths, and Experimental Evidence. J Phys Chem B 2022; 126:4339-4353. [PMID: 35671130 DOI: 10.1021/acs.jpcb.2c01808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We introduce a molecular-based route to the evaluation of the osmotic second virial coefficients of dissociative solutes in dilute binary solutions, according to a general molecular thermodynamic solvation formalism of electrolyte solutions. We discuss the underlying solvation fundamentals and derive rigorous expressions leading to (i) the functional relationship among the osmotic second virial coefficients and the limiting composition behavior of the non-Coulombic contribution to the Kirkwood-Buff integral of the solute-solute interactions, the corresponding composition slope of the mean activity coefficient of the electrolyte solute, and a precisely defined solute-solvent intermolecular interaction asymmetry that characterizes unambiguously the solution non-ideality; (ii) the self-consistent calculation of the osmotic second virial coefficients of electrolytes as defined by the composition expansion along different thermodynamic paths and/or composition variables; (iii) the microstructural interpretation of Hill's isobaric-isothermal osmotic second virial coefficient in terms of Kirkwood-Buff correlation function integrals and its relationships to other osmotic coefficients from composition expansions along alternative thermodynamic paths; and (iv) the identification of drawbacks in the implementation of previous methods, originally intended for non-electrolyte systems, to systems involving dissociative solutes. The proposed formalism provides the fundamentally based foundations to the determination of the osmotic second virial coefficients of any type of electrolyte solute, whose thermodynamic expressions converge naturally to the non-electrolyte ones by setting to unity the solute stoichiometric coefficient ν. Following the formal results, we illustrate the formalism with the calculation of a variety of osmotic second virial coefficients involving a wide selection of aqueous solutions at ambient conditions and comprising a wide range of anion-cation type combinations characterized by 2 ≤ ν ≤ 6. Finally, we interpret the behavior of the resulting osmotic virial coefficients in terms of the solute-solvent intermolecular interaction asymmetry, discuss the experimental data requirements for the accurate evaluation of the osmotic second virial coefficients, and provide some observations as well as their modeling implications.
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Affiliation(s)
- Ariel A Chialvo
- Retired scientist, Knoxville, Tennessee 37922-3108, United States
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20
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Design principles of PI(4,5)P 2 clustering under protein-free conditions: Specific cation effects and calcium-potassium synergy. Proc Natl Acad Sci U S A 2022; 119:e2202647119. [PMID: 35605121 DOI: 10.1073/pnas.2202647119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
SignificanceClustering of phosphatidylinositol 4,5-bisphosphate (PIP2) with proteins into what are known as "PIP2 rafts" is a critical component of intracellular signaling, yet little is known about PIP2 clusters at the atomic level. Using molecular dynamics simulations and network theory, this paper shows that Ca2+ generates large clusters by linking PIP2 dimers already formed by doubly charged P4/P5 phosphates, while monovalent cations form smaller and less-stable clusters by adding PIP2 monomers preferentially via weaker interactions with P4/P5 (for Na+) or with glycerol P1 (for K+). Synergy arises between K+ and Ca2+ because each ion forms linkages with different phosphates, thereby giving clusters more ways to grow. This explains why Ca2+ is pumped into cells by ion channels to form PIP2 rafts.
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21
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Simončič M, Lukšič M. Modulating Role of Co-Solutes in Complexation between Bovine Serum Albumin and Sodium Polystyrene Sulfonate. Polymers (Basel) 2022; 14:1245. [PMID: 35335575 PMCID: PMC8953846 DOI: 10.3390/polym14061245] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/12/2022] [Accepted: 03/18/2022] [Indexed: 11/28/2022] Open
Abstract
The action of three types of co-solutes: (i) salts (NaCl, NaBr, NaI), (ii) polymer (polyethylene glycol; PEG-400, PEG-3000, PEG-20000), and (iii) sugars (sucrose, sucralose) on the complexation between bovine serum albumin (BSA) and sodium polystyrene sulfonate (NaPSS) was studied. Three critical pH parameters were extracted from the pH dependence of the solution’s turbidity: pHc corresponding to the formation of the soluble complexes, pHΦ corresponding to the formation of the insoluble complexes, and pHopt corresponding to the charge neutralization of the complexes. In the presence of salts, the formation of soluble and insoluble complexes as well as the charge neutralization of complexes was hindered, which is a consequence of the electrostatic screening of attractive interactions between BSA and NaPSS. Distinct anion-specific trends were observed in which the stabilizing effect of the salt increased in the order: NaCl < NaBr < NaI. The presence of PEG, regardless of its molecular weight, showed no measurable effect on the formation of soluble complexes. PEG-400 and PEG-3000 showed no effect on the formation of insoluble complexes, but PEG-20000 in high concentrations promoted their formation due to the molecular crowding effect. The presence of sugar molecules had little effect on BSA-NaPSS complexation. Sucralose showed a minor stabilizing effect with respect to the onset of complex formation, which was due to its propensity to the protein surface. This was confirmed by the fluorescence quenching assay (Stern-Volmer relationship) and all-atom MD simulations. This study highlights that when evaluating the modulatory effect of co-solutes on protein-polyelectrolyte interactions, (co-solute)-protein interactions and their subsequent impact on protein aggregation must also be considered.
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Affiliation(s)
- Matjaž Simončič
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
| | - Miha Lukšič
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
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22
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Graham TR, Nienhuis ET, Reynolds JG, Marcial J, Loring JS, Rosso KM, Pearce CI. Sodium site occupancy and phosphate speciation in natrophosphate are invariant to changes in NaF and Na 3PO 4 concentration. Inorg Chem Front 2022. [DOI: 10.1039/d2qi00868h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Analysis of multimodal characterization of Natrophosphate suggests that the crystalline structure is preserved across a range of synthesis conditions.
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Affiliation(s)
- Trent R. Graham
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | - Emily T. Nienhuis
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | - Jacob G. Reynolds
- Washington River Protection Solutions, LLC, Richland, Washington 99352, USA
| | - Jose Marcial
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | - John S. Loring
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | - Kevin M. Rosso
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | - Carolyn I. Pearce
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA
- Department of Crop and Soil Sciences, Washington State University, Pullman, Washington 99164, USA
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23
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Miranda-Quintana RA, Smiatek J. Specific Ion Effects in Different Media: Current Status and Future Challenges. J Phys Chem B 2021; 125:13840-13849. [PMID: 34918938 DOI: 10.1021/acs.jpcb.1c07957] [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
We discuss the current state of research as well as the future challenges for a deeper understanding of specific ion effects in protic and aprotic solvents as well as various additional media. Despite recent interest in solute or interfacial effects, we focus exclusively on the specific properties of ions in bulk electrolyte solutions. Corresponding results show that many mechanisms remain unknown for these simple media, although theoretical, computational, and experimental studies have provided some insights into explaining individual observations. In particular, the importance of local interactions and electronic properties is emphasized, which enabled a more consistent interpretation of specific ion effects over the past years. Despite current insufficient knowledge, we also discuss future challenges in relation to dynamic properties as well as the influence of different concentrations, different solvents, and solute contributions to gain a deeper understanding of specific ion effects for technological applications.
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Affiliation(s)
- Ramón Alain Miranda-Quintana
- Department of Chemistry and Quantum Theory Project, University of Florida, Gainesville, Florida 32611, United States
| | - Jens Smiatek
- Institute for Computational Physics, University of Stuttgart, D-70569 Stuttgart, Germany.,Digitalization Development Biologicals CMC, Boehringer Ingelheim Pharma GmbH & Co. KG, D-88397 Biberach (Riss), Germany
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24
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McPherson A. Structures of additional crystal forms of Satellite tobacco mosaic virus grown from a variety of salts. Acta Crystallogr F Struct Biol Commun 2021; 77:473-483. [PMID: 34866603 PMCID: PMC8647216 DOI: 10.1107/s2053230x21011547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 11/02/2021] [Indexed: 11/10/2022] Open
Abstract
The structures of new crystal forms of Satellite tobacco mosaic virus (STMV) are described. These belong to space groups I2, P21212 (a low-resolution form), R3 (H3) and P23. The R3 crystals are 50%/50% twinned, as are two instances of the P23 crystals. The I2 and P21212 crystals were grown from ammonium sulfate solutions, as was one crystal in space group P23, while the R3 and the other P23 crystals were grown from sodium chloride, sodium bromide and sodium nitrate. The monoclinic and orthorhombic crystals have half a virus particle as the asymmetric unit, while the rhombohedral and cubic crystals have one third of a virus particle. RNA segments organized about the icosahedral twofold axes were present in crystals grown from ammonium sulfate and sodium chloride, as in the canonical I222 crystals (PDB entry 4oq8), but were not observed in crystals grown from sodium bromide and sodium nitrate. Bromide and nitrate ions generally replaced the RNA phosphates present in the I222 crystals, including the phosphates seen on fivefold axes, and were also found at threefold vertices in both the rhombohedral and cubic forms. An additional anion was also found on the fivefold axis 5 Å from the first anion, and slightly outside the capsid in crystals grown from sodium chloride, sodium bromide and sodium nitrate, suggesting that the path along the symmetry axis might be an ion channel. The electron densities for RNA strands at individual icosahedral dyads, as well as at the amino-terminal peptides of protein subunits, exhibited a diversity of orientations, in particular the residues at the ends.
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Affiliation(s)
- Alexander McPherson
- Department of Molecular Biology and Biochemistry, University of California, 530A Steinhaus Hall, Irvine, CA 92697-3900, USA
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25
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Oberleithner H. Quantifying salt sensitivity. Biol Chem 2021; 402:1597-1602. [PMID: 34505462 DOI: 10.1515/hsz-2021-0206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 07/03/2021] [Indexed: 11/15/2022]
Abstract
Inner surfaces of blood vessels and outer surfaces of erythrocytes are coated with a negatively charged protective film of proteoglycans, which serves as an effective buffer system for the positively charged sodium ions. If this protective coating is poorly developed or impaired, it loses its buffering capacity. As a consequence, the organism becomes increasingly sensitive to sodium, which in the long run leads to organ damage, especially if daily salt consumption is high. Recently, it has become possible to quantify salt sensitivity using a technically simple method - the salt blood test (SBT). Aim of this mini-review is to explain the physiological concept underlying the SBT and its potential practical relevance in the prevention of cardiovascular disease.
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Affiliation(s)
- Hans Oberleithner
- Institute of Physiology II, Medical Faculty, University of Münster, 48149 Münster, Germany
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26
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Reynolds JG. Solubilities in aqueous nitrate solutions that appear to reverse the law of mass action. Phys Chem Chem Phys 2021; 23:21407-21418. [PMID: 34553199 DOI: 10.1039/d1cp03124d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Non-ideal aqueous electrolyte solutions have been studied since the start of the application of thermodynamics to chemistry in the late 19th century. The present study examines some of the most extreme non-ideal behavior ever observed: solubilities of alkali and NH4+ nitrate salts in water that appear to behave the opposite of how the Law of Mass Action would predict. A literature review discovered that the solubilities of NH4NO3 and many alkali nitrate salts increases when another nitrate-bearing electrolyte is added to solution. These occurrences were in concentrated solutions with insufficient water to provide all ions their preferred hydration number without sharing waters between ions. This water deficit results in the formation of contact ion-pairs as well as larger ion-clusters. These ion-clusters may be favored when there is more than one type of monovalent cation present.
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Affiliation(s)
- Jacob G Reynolds
- Washington River Protection Solutions, LLC, P. O. Box 850, Richland, WA, 99352, USA.
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27
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Guo Y, Nishida N, Hoshino T. Quantifying the Separation of Positive and Negative Areas in Electrostatic Potential for Predicting Feasibility of Ammonium Sulfate for Protein Crystallization. J Chem Inf Model 2021; 61:4571-4581. [PMID: 34565151 DOI: 10.1021/acs.jcim.1c00505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ammonium sulfate (AS) and poly(ethylene glycol) (PEG) are the most popular precipitants in protein crystallization. Some proteins are preferably crystallized by AS, while some are by PEG. The electrostatic potential is related to the preference of the precipitant agents. The iso-surfaces of the electrostatic potentials for the AS-crystallized proteins display a common shape and a distinct separation between the positive and negative areas. In contrast, the PEG-crystallized proteins show unclear positive and negative separation. In this work, we propose schemes to quantitatively evaluate the separation for predicting which precipitant is favorable for crystal growth between AS or PEG. Three methods were attempted to quantify the amplitude of the separation, separation distance, dipole moment, and shape regularity. The positive and negative areas are approximated to the spherical potentials caused by point charges. The first method is a measurement of the distance between the positive and negative point charges. The second one is an assessment including the quantity of electric charge into the distance. The last one is an approach monitoring the clarity of the positive and negative separation. The average value for 25 kinds of AS-preferring proteins was higher than that for the PEG-preferring ones in all three methods. Therefore, every method can distinguish the proteins preferring AS for crystal growth from those preferring PEG. These methods require an iso-surface of the electrostatic potential depicted at a certain contouring value. The shape of the iso-surface depends on the contouring value. The dependency on contour was examined by depicting the iso-surfaces of electrostatic potential with three values at ±0.8, ±0.5, and ±0.2 kT/e. While reducing the contouring value leads to the increase in separation distance and the decrease in shape regularity, dipole moment is independent of the alteration of contouring value. While the AS-preferring proteins are distinguishable from the PEG-preferring ones in any contouring values, the iso-surface at ±0.5 kT/e seems adequate for regular use. The dipole moment assessment is feasible for the choice of potent precipitants for crystal growth in experiments.
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Affiliation(s)
- Yan Guo
- Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675, Japan
| | - Noritaka Nishida
- Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675, Japan
| | - Tyuji Hoshino
- Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675, Japan
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28
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Perera RM, Gupta S, Li T, Bleuel M, Hong K, Schneider GJ. Influence of NaCl on shape deformation of polymersomes. SOFT MATTER 2021; 17:4452-4463. [PMID: 33908443 DOI: 10.1039/d0sm02271c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Polymersomes frequently appear in the literature as promising candidates for a wide range of applications from targeted drug delivery to nanoreactors. From a cell mimetic point of view, it is important to understand the size and shape changes of the vesicles in the physiological environment since that can influence the drug delivery mechanism. In this work we studied the structural features of polymersomes consisting of poly(ethylene glycol)-poly(dimethylsiloxane)-poly(ethylene glycol) at the nanoscopic length scale in the presence of NaCl, which is a very common molecule in the biotic aqueous environment. We used dynamic light scattering (DLS), cryo-TEM, small angle neutron scattering (SANS) and small angle X-ray scattering (SAXS). We observed transformation of polymersomes from spherical to elongated vesicles at low salt concentration and into multivesicular structures at high salt concentration. Model fitting analysis of SANS data indicated a reduction of vesicle radius up to 47% and from the SAXS data we observed an increase in membrane thickness up to 8% and an increase of the PDMS hydrophobic segment up to 11% indicating stretching of the membrane due to osmotic imbalance. Also, from the increase in the interlamellar repeat distance up to 98% under high salt concentrations, we concluded that the shape and structural changes observed in the polymersomes are a combined result of osmotic pressure change and ion-membrane interactions.
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Affiliation(s)
- Rasangi M Perera
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA.
| | - Sudipta Gupta
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA.
| | - Tianyu Li
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA
| | - Markus Bleuel
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-8562, USA and Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742-2115, USA
| | - Kunlun Hong
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Gerald J Schneider
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA. and Department of Physics & Astronomy, Louisiana State University, Baton Rouge, LA 70803, USA.
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29
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Sterling JD, Jiang W, Botello-Smith WM, Luo YL. Ion Pairing and Dielectric Decrement in Glycosaminoglycan Brushes. J Phys Chem B 2021; 125:2771-2780. [PMID: 33662212 DOI: 10.1021/acs.jpcb.0c11571] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cell-surface polysaccharides are essential to many aspects of physiology, serving as a highly conserved evolutionary feature of life and as an important part of the innate immune system in mammals. Here, as simplified biophysical models of these sugar coatings, we present results of molecular dynamics simulations of hyaluronic acid and heparin brushes that show important effects of ion pairing, water dielectric decrease, and coion exclusion. As in prior studies of macromolecular crowding under physiologically relevant salt concentrations, our results show equilibria with electroneutrality attained through screening and pairing of brush anionic charges by monovalent cations at the atomistic detail. Most surprising is the reversal of the Donnan potential obtained from both nonpolarizable and Drude polarizable force fields, in contrast to what would be expected based on electrostatic Boltzmann partitioning alone. Water dielectric decrement within the brush domain is also associated with Born hydration-driven cation exclusion from the brush. We observe that the primary partition energy attracting cations to attain brush electroneutrality is the ion pairing or salt-bridge energy. Potassium and sodium pairings to glycosaminoglycan carboxylates and sulfates show similar abundance of contact-pairing and solvent-separated pairing. We conclude that in these crowded macromolecular brushes, ion-pairing, Born-hydration, and electrostatic potential energies all contribute to attain electroneutrality and should therefore contribute in mean-field models to accurately represent brush electrostatics.
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Affiliation(s)
- James D Sterling
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, 535 Watson Dr., Claremont, California 91711, United States
| | - Wenjuan Jiang
- College of Pharmacy, Western University of Health Sciences, 309 E. Second Street, Pomona, California 91766, United States
| | - Wesley M Botello-Smith
- College of Pharmacy, Western University of Health Sciences, 309 E. Second Street, Pomona, California 91766, United States
| | - Yun L Luo
- College of Pharmacy, Western University of Health Sciences, 309 E. Second Street, Pomona, California 91766, United States
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30
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Kobrak MN, Nykypanchuk D, Janssen CHC. Relationship between liquid nanoscale structure in solvents and the strength of the Hofmeister effect in extraction experiments. Phys Chem Chem Phys 2021; 23:6266-6277. [PMID: 33735349 DOI: 10.1039/d0cp05973k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this study, we used mixtures of carboxylic acids and amines as solvents for the liquid-liquid extraction of copper salts with various anions from aqueous phase, and systematically varied the acid/amine ratio to determine its influence on extraction efficiency. The organic phases resulting from these extraction experiments were studied using small-angle X-ray scattering (SAXS), establishing a connection between the extraction process and the liquid structure. A relationship is found between the extent of extraction for the metal salt, the strength of the Hofmeister effect of the anions of the salt, and the characteristic lengthscale of the observed liquid nanoscale structure before and after extraction.
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Affiliation(s)
- Mark N Kobrak
- Department of Chemistry, Brooklyn College of the City University of New York, 2900 Bedford Ave., Brooklyn, NY 11210, USA and Department of Chemistry, Graduate Center of the City University of New York, 365 Fifth Ave., New York, NY 10016, USA
| | - Dmytro Nykypanchuk
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Camiel H C Janssen
- Departamento de Ingeniería Química, Facultad de Química, Universidad Nacional Autónoma de México, Circuito Exterior S/N, Coyoacán, Cd. Universitaria, 04510 Ciudad de México, Mexico.
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31
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Kalayan J, Henchman RH. Convergence behaviour of solvation shells in simulated liquids. Phys Chem Chem Phys 2021; 23:4892-4900. [PMID: 33616583 DOI: 10.1039/d0cp05903j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A convenient way to analyse solvent structure around a solute is to use solvation shells, whereby solvent position around the solute is discretised by the size of a solvent molecule, leading to multiple shells around the solute. The two main ways to define multiple shells around a solute are either directly with respect to the solute, called solute-centric, or locally for both solute and solvent molecules alike. It might be assumed that both methods lead to solvation shells with similar properties. However, our analysis suggests otherwise. Solvation shells are analysed in a series of simulations of five pure liquids of differing polarity. Shells are defined locally working outwards from each molecule treated as a reference molecule using two methods: the cutoff at the first minimum in the radial distribution function and the parameter-free Relative Angular Distance method (RAD). The molecular properties studied are potential energy, coordination number and coordination radius. Rather than converging to bulk values, as might be expected for pure solvents, properties are found to deviate as a function of shell index. This behaviour occurs because molecules with larger coordination numbers and radius have more neighbours, which make them more likely to be connected to the reference molecule via fewer shells. The effect is amplified for RAD because of its more variable coordination radii and for water with its more open structure and stronger interactions. These findings indicate that locally defined shells should not be thought of as directly comparable to solute-centric shells or to distance. As well as showing how box size and cutoff affect the non-convergence, to restore convergence we propose a hybrid method by defining a new set of shells with boundaries at the uppermost distance of each locally derived shell.
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Affiliation(s)
- Jas Kalayan
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK. and Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Richard H Henchman
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK. and Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
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32
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Pathak JA, Nugent S, Bender MF, Roberts CJ, Curtis RJ, Douglas JF. Comparison of Huggins Coefficients and Osmotic Second Virial Coefficients of Buffered Solutions of Monoclonal Antibodies. Polymers (Basel) 2021; 13:601. [PMID: 33671342 PMCID: PMC7922252 DOI: 10.3390/polym13040601] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 02/12/2021] [Accepted: 02/14/2021] [Indexed: 01/08/2023] Open
Abstract
The Huggins coefficient kH is a well-known metric for quantifying the increase in solution viscosity arising from intermolecular interactions in relatively dilute macromolecular solutions, and there has been much interest in this solution property in connection with developing improved antibody therapeutics. While numerous kH measurements have been reported for select monoclonal antibodies (mAbs) solutions, there has been limited study of kH in terms of the fundamental molecular interactions that determine this property. In this paper, we compare measurements of the osmotic second virial coefficient B22, a common metric of intermolecular and interparticle interaction strength, to measurements of kH for model antibody solutions. This comparison is motivated by the seminal work of Russel for hard sphere particles having a short-range "sticky" interparticle interaction, and we also compare our data with known results for uncharged flexible polymers having variable excluded volume interactions because proteins are polypeptide chains. Our observations indicate that neither the adhesive hard sphere model, a common colloidal model of globular proteins, nor the familiar uncharged flexible polymer model, an excellent model of intrinsically disordered proteins, describes the dependence of kH of these antibodies on B22. Clearly, an improved understanding of protein and ion solvation by water as well as dipole-dipole and charge-dipole effects is required to understand the significance of kH from the standpoint of fundamental protein-protein interactions. Despite shortcomings in our theoretical understanding of kH for antibody solutions, this quantity provides a useful practical measure of the strength of interprotein interactions at elevated protein concentrations that is of direct significance for the development of antibody formulations that minimize the solution viscosity.
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Affiliation(s)
- Jai A. Pathak
- Vaccine Production Program (VPP), Vaccine Research Center (VRC), Formulation and Stabilization Sciences Department, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 9 W. Watkins Mill Rd., Gaithersburg, MD 20878, USA; (J.A.P.); (S.N.); (M.B.)
| | - Sean Nugent
- Vaccine Production Program (VPP), Vaccine Research Center (VRC), Formulation and Stabilization Sciences Department, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 9 W. Watkins Mill Rd., Gaithersburg, MD 20878, USA; (J.A.P.); (S.N.); (M.B.)
| | - Michael F. Bender
- Vaccine Production Program (VPP), Vaccine Research Center (VRC), Formulation and Stabilization Sciences Department, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 9 W. Watkins Mill Rd., Gaithersburg, MD 20878, USA; (J.A.P.); (S.N.); (M.B.)
| | - Christopher J. Roberts
- Colburn Laboratory, Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716, USA;
| | - Robin J. Curtis
- Department of Chemical Engineering and Analytical Science, University of Manchester, Oxford Road, Manchester M13 9PL, UK;
| | - Jack F. Douglas
- Materials Science and Engineering Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899-8544, USA
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33
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Neal JF, Saha A, Zerkle MM, Zhao W, Rogers MM, Flood AH, Allen HC. Molecular Recognition and Hydration Energy Mismatch Combine To Inform Ion Binding Selectivity at Aqueous Interfaces. J Phys Chem A 2020; 124:10171-10180. [DOI: 10.1021/acs.jpca.0c09568] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Jennifer F. Neal
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Ankur Saha
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Mia M. Zerkle
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Wei Zhao
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Mickey M. Rogers
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Amar H. Flood
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Heather C. Allen
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
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34
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Yao W, Wang K, Wu A, Reed WF, Gibb BC. Anion binding to ubiquitin and its relevance to the Hofmeister effects. Chem Sci 2020; 12:320-330. [PMID: 34163600 PMCID: PMC8178748 DOI: 10.1039/d0sc04245e] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/29/2020] [Indexed: 02/01/2023] Open
Abstract
Although the non-covalent interactions between proteins and salts contributing to the Hofmeister effects have been generally mapped, there are many questions regarding the specifics of these interactions. We report here studies involving the small protein ubiquitin and salts of polarizable anions. These studies reveal a complex interplay between the reverse Hofmeister effect at low pH, the salting-in Hofmeister effect at higher pH, and six anion binding sites in ubiquitin at the root of these phenomena. These sites are all located at protuberances of preorganized secondary structure, and although stronger at low pH, are still apparent when ubiquitin possesses no net charge. These results demonstrate the traceability of these Hofmeister phenomena and suggest new strategies for understanding the supramolecular properties of proteins.
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Affiliation(s)
- Wei Yao
- Department of Chemistry, Tulane University New Orleans LA 70118 USA
| | - Kaiyu Wang
- Department of Chemistry, Tulane University New Orleans LA 70118 USA
| | - Aide Wu
- Department of Physics and Engineering Physics, Tulane University New Orleans LA 70118 USA
| | - Wayne F Reed
- Department of Physics and Engineering Physics, Tulane University New Orleans LA 70118 USA
| | - Bruce C Gibb
- Department of Chemistry, Tulane University New Orleans LA 70118 USA
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35
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Coordination environment variations in multinuclear trigonal bipyramid Co(II) complexes bearing tetradentate sulfonamide N-donors and phenoxazinone synthase activities. Inorganica Chim Acta 2020. [DOI: 10.1016/j.ica.2020.119664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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36
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Okamoto R, Koga K, Onuki A. Theory of electrolytes including steric, attractive, and hydration interactions. J Chem Phys 2020; 153:074503. [PMID: 32828079 DOI: 10.1063/5.0015446] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
We present a continuum theory of electrolytes composed of a waterlike solvent and univalent ions. First, we start with a density functional F for the coarse-grained solvent, cation, and anion densities, including the Debye-Hückel free energy, the Coulombic interaction, and the direct interactions among these three components. These densities fluctuate obeying the distribution ∝exp(-F/kBT). Eliminating the solvent density deviation in F, we obtain the effective non-Coulombic interactions among the ions, which consist of the direct ones and the solvent-mediated ones. We then derive general expressions for the ion correlation, the apparent partial volume, and the activity and osmotic coefficients up to linear order in the average salt density ns. Second, we perform numerical analysis using the Mansoori-Carnahan-Starling-Leland model [J. Chem. Phys. 54, 1523 (1971)] for three-component hardspheres. The effective interactions sensitively depend on the cation and anion sizes due to competition between the steric and hydration effects, which are repulsive between small-large ion pairs and attractive between symmetric pairs. These agree with previous experiments and Collins' rule [Biophys. J. 72, 65 (1997)]. We also give simple approximate expressions for the ionic interaction coefficients valid for any ion sizes.
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Affiliation(s)
- Ryuichi Okamoto
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Kenichiro Koga
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Akira Onuki
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
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37
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Higaki Y, Kobayashi M, Takahara A. Hydration State Variation of Polyzwitterion Brushes through Interplay with Ions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:9015-9024. [PMID: 32677837 DOI: 10.1021/acs.langmuir.0c01672] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Polyzwitterions have emerged as a new class of antifouling materials alternating poly(ethylene glycol). The exemplary biopassivation and lubrication behaviors are often attributed to the particular chemical structure of zwitterions, which involve a large dipole moment of the charged groups and a neutral net charge, while the hydration state and dynamics also associate with these characteristics. Polymer brushes composed of surface-tethered polyzwitterion chains produced by surface-initiated controlled radical polymerization have been developed as thin films which exhibit excellent antifouling and lubrication properties. In past decades, numerous studies have been devoted to examining the structure and dynamics of polyzwitterion brush chains in aqueous solutions. This feature article provides an overview of recent studies exploring the hydration state of polyzwitterion brushes with specular neutron reflectivity, highlights some newly published work on the nonuniform equilibrium structure, ion concentration dependence, ion specificity, and the effects of charge spacer length in the zwitterions, and discusses future perspective in this field.
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Affiliation(s)
- Yuji Higaki
- Department of Integrated Science and Technology, Faculty of Science and Technology, Oita University, 700 Dannoharu, Oita 870-1192, Japan
| | - Motoyasu Kobayashi
- School of Advanced Engineering, Kogakuin University, Tokyo 192-0015, Japan
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