301
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Lysozyme stability and amyloid fibrillization dependence on Hofmeister anions in acidic pH. J Biol Inorg Chem 2015; 20:921-33. [DOI: 10.1007/s00775-015-1276-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 05/31/2015] [Indexed: 10/23/2022]
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302
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Ou SC, Cui D, Wezowicz M, Taufer M, Patel S. Free energetics of carbon nanotube association in aqueous inorganic NaI salt solutions: Temperature effects using all-atom molecular dynamics simulations. J Comput Chem 2015; 36:1196-212. [PMID: 25868455 PMCID: PMC4445429 DOI: 10.1002/jcc.23906] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 01/22/2015] [Accepted: 02/21/2015] [Indexed: 11/06/2022]
Abstract
In this study, we examine the temperature dependence of free energetics of nanotube association using graphical processing unit-enabled all-atom molecular dynamics simulations (FEN ZI) with two (10,10) single-walled carbon nanotubes in 3 m NaI aqueous salt solution. Results suggest that the free energy, enthalpy and entropy changes for the association process are all reduced at the high temperature, in agreement with previous investigations using other hydrophobes. Via the decomposition of free energy into individual components, we found that solvent contribution (including water, anion, and cation contributions) is correlated with the spatial distribution of the corresponding species and is influenced distinctly by the temperature. We studied the spatial distribution and the structure of the solvent in different regions: intertube, intratube and the bulk solvent. By calculating the fluctuation of coarse-grained tube-solvent surfaces, we found that tube-water interfacial fluctuation exhibits the strongest temperature dependence. By taking ions to be a solvent-like medium in the absence of water, tube-anion interfacial fluctuation shows similar but weaker dependence on temperature, while tube-cation interfacial fluctuation shows no dependence in general. These characteristics are discussed via the malleability of their corresponding solvation shells relative to the nanotube surface. Hydrogen bonding profiles and tetrahedrality of water arrangement are also computed to compare the structure of solvent in the solvent bulk and intertube region. The hydrophobic confinement induces a relatively lower concentration environment in the intertube region, therefore causing different intertube solvent structures which depend on the tube separation. This study is relevant in the continuing discourse on hydrophobic interactions (as they impact generally a broad class of phenomena in biology, biochemistry, and materials science and soft condensed matter research), and interpretations of hydrophobicity in terms of alternative but parallel signatures such as interfacial fluctuations, dewetting transitions, and enhanced fluctuation probabilities at interfaces.
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Affiliation(s)
- Shu-Ching Ou
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA
| | - Di Cui
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA
| | - Matthew Wezowicz
- Department of Computer and Information Sciences, University of Delaware, Newark, Delaware 19716, USA
| | - Michela Taufer
- Department of Computer and Information Sciences, University of Delaware, Newark, Delaware 19716, USA
| | - Sandeep Patel
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA
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303
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Solvent Properties of Water in Aqueous Solutions of Elastin-Like Polypeptide. Int J Mol Sci 2015; 16:13528-47. [PMID: 26075870 PMCID: PMC4490507 DOI: 10.3390/ijms160613528] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 06/10/2015] [Indexed: 11/29/2022] Open
Abstract
The phase-transition temperatures of an elastin-like polypeptide (ELP) with the (GVGVP)40 sequence and solvent dipolarity/polarizability, hydrogen-bond donor acidity, and hydrogen-bond acceptor basicity in its aqueous solutions were quantified in the absence and presence of different salts (Na2SO4, NaCl, NaClO4, and NaSCN) and various osmolytes (sucrose, sorbitol, trehalose, and trimethylamine N-oxide (TMAO)). All osmolytes decreased the ELP phase-transition temperature, whereas NaCl and Na2SO4 decreased, and NaSCN and NaClO4 increased it. The determined phase-transition temperatures may be described as a linear combination of the solvent’s dipolarity/polarizability and hydrogen-bond donor acidity. The linear relationship established for the phase-transition temperature in the presence of salts differs quantitatively from that in the presence of osmolytes, in agreement with different (direct and indirect) mechanisms of the influence of salts and osmolytes on the ELP phase-transition temperature.
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304
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Pan Z, Wu T, Jin T, Liu Y, Nagata Y, Zhang R, Zhuang W. Low frequency 2D Raman-THz spectroscopy of ionic solution: A simulation study. J Chem Phys 2015; 142:212419. [DOI: 10.1063/1.4917260] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Zhijun Pan
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Tianmin Wu
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Tan Jin
- State Key Lab of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China
| | - Yong Liu
- State Key Lab of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China
| | - Yuki Nagata
- Department for Molecular Spectroscopy, Max-Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Ruiting Zhang
- State Key Lab of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China
| | - Wei Zhuang
- State Key Lab of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China
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305
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Reddy PM, Umapathi R, Venkatesu P. Interactions of ionic liquids with hydration layer of poly(N-isopropylacrylamide): comprehensive analysis of biophysical techniques results. Phys Chem Chem Phys 2015; 16:10708-18. [PMID: 24756081 DOI: 10.1039/c4cp00010b] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Here, we report comprehensive analysis of biophysical technique results for the influence of ionic liquids (ILs) containing the same cation, 1-butyl-3-methylimidazolium (Bmim(+)), and commonly used anions such as SCN(-), BF4(-), I(-), Br(-), Cl(-), CH3COO(-) and HSO4(-) on the phase transition temperature of poly(N-isopropylacrylamide) (PNIPAM) aqueous solution. Further, the effect of these ILs on bovine serum albumin (BSA) has also been studied. The modulations in UV-visible (UV-vis) absorption spectra, fluorescence intensity spectra, viscosity (η), hydrodynamic diameter (dH), Fourier transform infrared (FTIR) spectra and scanning electron microscopy (SEM) micrographs clearly reflect the change in the hydration state of PNIPAM in the presence of ILs. The observed single phase transition of PNIPAM aqueous solution at higher concentration of IL is the result of weak ion-ion pair interactions in IL.
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306
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Gibb CLD, Oertling EE, Velaga S, Gibb BC. Thermodynamic Profiles of Salt Effects on a Host–Guest System: New Insight into the Hofmeister Effect. J Phys Chem B 2015; 119:5624-38. [DOI: 10.1021/acs.jpcb.5b01708] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Corinne L. D. Gibb
- Department
of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Estelle E. Oertling
- Department
of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Santhosh Velaga
- Department
of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Bruce C. Gibb
- Department
of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
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307
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Song J, Kang TH, Kim MW, Han S. Ion specific effects: decoupling ion-ion and ion-water interactions. Phys Chem Chem Phys 2015; 17:8306-22. [PMID: 25761273 PMCID: PMC4656249 DOI: 10.1039/c4cp05992a] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Ion-specific effects in aqueous solution, known as the Hofmeister effect, are prevalent in diverse systems ranging from pure ionic to complex protein solutions. The objective of this paper is to explicitly demonstrate how complex ion-ion and ion-water interactions manifest themselves in the Hofmeister effect based on a series of recent experimental observations. These effects are not considered in the classical descriptions of ion effects, such as the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, and therefore they fail to describe the origin of the phenomenological Hofmeister effect. However, given that models considering the basic forces of electrostatic and van der Waals interactions can offer rationalization for the core experimental observations, a universal interaction model stands a chance of being developed. In this perspective, we separately derive the contribution from ion-ion electrostatic interactions and ion-water interactions from second harmonic generation (SHG) data at the air-ion solution interface, which yields an estimate of the ion-water interactions in solution. The Hofmeister ion effect observed for biological solutes in solution should be similarly influenced by contributions from ion-ion and ion-water interactions, where the same ion-water interaction parameters derived from SHG data at the air-ion solution interface could be applicable. A key experimental data set available from solution systems to probe ion-water interactions is the modulation of water diffusion dynamics near ions in a bulk ion solution, as well as near biological liposome surfaces. This is obtained from Overhauser dynamic nuclear polarization (ODNP), a nuclear magnetic resonance (NMR) relaxometry technique. The surface water diffusivity is influenced by the contribution from ion-water interactions, both from localized surface charges and adsorbed ions, although the relative contribution of the former is larger on liposome surfaces. In this perspective, ion-water interaction energy values derived from experimental data for various ions are compared with theoretical values in the literature. Ultimately, quantifying ion-induced changes in the surface energy for the purpose of developing valid theoretical models for ion-water interactions will be critical to rationalizing the Hofmeister effect.
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Affiliation(s)
- Jinsuk Song
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
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308
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Oncsik T, Trefalt G, Borkovec M, Szilagyi I. Specific ion effects on particle aggregation induced by monovalent salts within the Hofmeister series. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:3799-807. [PMID: 25777544 DOI: 10.1021/acs.langmuir.5b00225] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Ion specific effects of monovalent salts on charging and aggregation for two types of polystyrene latex particles were investigated by electrophoresis and time-resolved light scattering. The chemical composition of the electrolytes was systematically varied in the experiments. Accordingly, NaH2PO4, NaF, NaCl, NaBr, NaNO3, and NaSCN were used to vary the anions and N(CH3)4Cl, NH4Cl, CsCl, KCl, NaCl, and LiCl for the cations. The salt concentration dependence of the electrophoretic mobilities indicates that the surface charge was screened by the counterions when their concentrations increased. For the SCN(-) ions, adsorption on positively charged particles leads to charge reversal. The aggregation rates are small at low electrolyte concentrations indicating stable dispersions under these conditions, and they increase with the salt concentration. When viscosity corrections are taken into account, no ion specific effects in the fast aggregation regime can be established. The slow and fast aggregation regimes are separated by the critical coagulation concentration (CCC). Within the experimental error, the CCCs are the same in systems containing different co-ions but the same counterions, with the exception of ammonium salts. However, the variation of counterions leads to different CCC values due to specific interaction of the counterions with the surface. These values follow the Hofmeister series for negatively charged sulfate latex particles, while the reversed order was observed for positively charged amidine latex. Comparison between experimental CCCs and those calculated by the theory of Derjaguin, Landau, Verwey, and Owerbeek reveals that variations in the surface charge due to ionic adsorption are mainly responsible for the ion specific effects in the aggregation process.
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Affiliation(s)
- Tamas Oncsik
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland
| | - Gregor Trefalt
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland
| | - Michal Borkovec
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland
| | - Istvan Szilagyi
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland
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309
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Benjamin I. Correlating structure and thermodynamics of hydrophobic–hydrophilic ion pairs in water. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.02.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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310
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Functionalizable low-fouling coatings for label-free biosensing in complex biological media: advances and applications. Anal Bioanal Chem 2015; 407:3927-53. [DOI: 10.1007/s00216-015-8606-5] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 02/20/2015] [Accepted: 02/27/2015] [Indexed: 12/31/2022]
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311
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Fox JM, Kang K, Sherman W, Héroux A, Sastry GM, Baghbanzadeh M, Lockett MR, Whitesides GM. Interactions between Hofmeister anions and the binding pocket of a protein. J Am Chem Soc 2015; 137:3859-66. [PMID: 25738615 PMCID: PMC6554743 DOI: 10.1021/jacs.5b00187] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This paper uses the binding pocket of human carbonic anhydrase II (HCAII, EC 4.2.1.1) as a tool to examine the properties of Hofmeister anions that determine (i) where, and how strongly, they associate with concavities on the surfaces of proteins and (ii) how, upon binding, they alter the structure of water within those concavities. Results from X-ray crystallography and isothermal titration calorimetry show that most anions associate with the binding pocket of HCAII by forming inner-sphere ion pairs with the Zn(2+) cofactor. In these ion pairs, the free energy of anion-Zn(2+) association is inversely proportional to the free energetic cost of anion dehydration; this relationship is consistent with the mechanism of ion pair formation suggested by the "law of matching water affinities". Iodide and bromide anions also associate with a hydrophobic declivity in the wall of the binding pocket. Molecular dynamics simulations suggest that anions, upon associating with Zn(2+), trigger rearrangements of water that extend up to 8 Å away from their surfaces. These findings expand the range of interactions previously thought to occur between ions and proteins by suggesting that (i) weakly hydrated anions can bind complementarily shaped hydrophobic declivities, and that (ii) ion-induced rearrangements of water within protein concavities can (in contrast with similar rearrangements in bulk water) extend well beyond the first hydration shells of the ions that trigger them. This study paints a picture of Hofmeister anions as a set of structurally varied ligands that differ in size, shape, and affinity for water and, thus, in their ability to bind to—and to alter the charge and hydration structure of—polar, nonpolar, and topographically complex concavities on the surfaces of proteins.
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Affiliation(s)
- Jerome M. Fox
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Kyungtae Kang
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Woody Sherman
- Schrödinger, 120 West 45th Street, New York, New York 10036, United States
| | - Annie Héroux
- Photon Science Division, Energy Sciences Directorate, Brookhaven National Laboratory, Building 745, Upton, New York 11937, United States
| | - G. Madhavi Sastry
- Schrödinger, Sanali Infopark, 8-2-120/113 Banjara Hills, Hyderabad 11937, Andhra Pradesh, India
| | - Mostafa Baghbanzadeh
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Matthew R. Lockett
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - George M. Whitesides
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
- Wyss Institute for Biologically Inspired Engineering, Harvard University, 60 Oxford Street, Cambridge, Massachusetts 02138, United States
- The Kavli Institute for Bionano Science and Technology, Harvard University, 29 Oxford Street, Cambridge, Massachusetts 02138, United States
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312
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Rembert KB, Okur HI, Hilty C, Cremer PS. An NH moiety is not required for anion binding to amides in aqueous solution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:3459-3464. [PMID: 25764296 DOI: 10.1021/acs.langmuir.5b00127] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Herein, we use a combination of thermodynamic and spectroscopic measurements to investigate the interactions of Hofmeister anions with a thermoresponsive polymer, poly(N,N-diethylacrylamide) (PDEA). This amide-based polymer does not contain an NH moiety in its chemical structure and, thus, can serve as a model to test if anions bind to amides in the absence of an NH site. The lower critical solution temperature (LCST) of PDEA was measured as a function of the concentration for 11 sodium salts in aqueous solutions, and followed a direct Hofmeister series for the ability of anions to precipitate the polymer. More strongly hydrated anions (CO3(2-), SO4(2-), S2O3(2-), H2PO4(-), F(-), and Cl(-)) linearly decreased the LCST of the polymer with increasing the salt concentration. Weakly hydrated anions (SCN(-), ClO4(-), I(-), NO3(-), and Br(-)) increased the LCST at lower salt concentrations but salted the polymer out at higher salt concentrations. Proton nuclear magnetic resonance (NMR) was used to probe the mechanism of the salting-in effect and showed apparent binding between weakly hydrated anions (SCN(-) and I(-)) and the α protons of the polymer backbone. Additional experiments performed by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy found little change in the amide I band upon the addition of salt, which is consistent with very limited, if any, interactions between the salt ions and the carbonyl moiety of the amide. These results support a molecular mechanism for ion-specific effects on proteins and model amides that does not specifically require an NH group to interact with the anions for the salting-in effect to occur.
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313
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Nagler K, Moeller R. Systematic investigation of germination responses of Bacillus subtilis spores in different high-salinity environments. FEMS Microbiol Ecol 2015; 91:fiv023. [PMID: 25764471 DOI: 10.1093/femsec/fiv023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/25/2015] [Indexed: 11/14/2022] Open
Abstract
High-salinity environments play an increasingly important role in ecology regarding soil salinization due to human-induced processes, but also need to be considered in terms of natural soil desiccation and extreme habitats. It has been shown previously that spore germination of the ubiquitous soil bacterium Bacillus subtilis is detrimentally affected by the presence of high NaCl concentrations, but the underlying mechanisms and effects of other salts remained obscure. To address these two points, we performed a systematic analysis with 32 different salts using spectrophotometric and microscopic methods. It could be shown that inhibitory strength varies considerably among different salts. Although osmotic effects seem to play an important role, ionic composition and concentration (especially of the anion) as well as chemical properties seem to be decisive for the extent of germination inhibition. At the current state of knowledge, fluxes of ions, Ca(2+)-DPA and water are likely affected by all salts, whereas the exact inhibition mechanism of each salt might further depend on the respective properties of the involved ions. Hence, the observed inhibition likely is a result of several phenomena interacting with each other. Altogether this study highlights the complex impact of ionic environments on the life cycle of spore formers.
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Affiliation(s)
- Katja Nagler
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Radiation Biology Department, Research Group Astrobiology, Linder Höhe, D-51147 Cologne (Köln), Germany
| | - Ralf Moeller
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Radiation Biology Department, Research Group Astrobiology, Linder Höhe, D-51147 Cologne (Köln), Germany
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314
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Rakel N, Bauer KC, Galm L, Hubbuch J. From osmotic second virial coefficient (B22 ) to phase behavior of a monoclonal antibody. Biotechnol Prog 2015; 31:438-51. [PMID: 25683855 DOI: 10.1002/btpr.2065] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 01/31/2015] [Indexed: 12/14/2022]
Abstract
Antibodies are complex macromolecules and their phase behavior as well as interactions within different solvents and precipitants are still not understood. To shed some light into the processes on a molecular dimension, the occurring self-interactions between antibody molecules were analyzed by means of the osmotic second virial coefficient (B22 ). The determined B22 follows qualitatively the phenomenological Hofmeister series describing the aggregation probability of antibodies for the various solvent compositions. However, a direct correlation between crystallization probability and B22 in form of a crystallization slot does not seem to be feasible for antibodies since the phase behavior is strongly dependent on their anisotropy. Kinetic parameters have to be taken into account due to the molecular size and complexity of the molecules. This is confirmed by a comparison of experimental data with a theoretical phase diagram. On the other hand the solubility is thermodynamically driven and therefore the B22 could be used to establish a universal solubility line for the monoclonal antibody mAb04c and different solvent compositions by using thermodynamic models.
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Affiliation(s)
- Natalie Rakel
- Section IV: Biomolecular Separation Engineering, Inst. of Engineering in Life Sciences, Karlsruhe Inst. of Technology, Engler-Bunte-Ring 1, Karlsruhe, 76131, Germany; Roche Diagnostics GmbH, Mannheim, Germany
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315
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Pastoor KJ, Rice CV. Cation Effects on the Phase Transition of N-isopropylacrylamide Hydrogels. MACROMOL CHEM PHYS 2015; 216:1024-1032. [PMID: 31595137 DOI: 10.1002/macp.201400573] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Polymers formed from N-isopropylacrylamide (NIPAM) are highly water soluble and undergo a temperature-induced phase transition to an insoluble state. The phase behavior is determined by competing hydrophilic and hydrophobic forces. In this report, additional insight regarding the effect soluble metals have on the phase transition process is provided by showing that cation solvation aids with stabilization of hydrophobic forces. This reduces barriers to rehydration and decreases thermodynamic entropy and enthalpy, obtained with variable-temperature 1H nuclear magnetic resonance spectroscopy of NIPAM hydrogels in D2O, NaCl, MgCl2, and CaCl2. For the series of cations studied, it is observed that the order of increasing effect to facilitate the phase transition is Ca2+ < Mg2+ < Na+. NaCl and MgCl2 exhibited similar effects on the thermodynamics of the collapsing process. However, significant differences in the phase transition thermodynamics are observed between MgCl2 and CaCl2 salt solutions. The influence on Stage 1 enthalpy and entropy values for CaCl2 solutions is approximately half that of the MgCl2 solutions. This difference is likely related to their charge density of Ca2+, which is approximately half that of Mg2+.
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Affiliation(s)
- Kevin J Pastoor
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, OK 73019, USA
| | - Charles V Rice
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, OK 73019, USA
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316
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Metrick MA, MacDonald G. Hofmeister ion effects on the solvation and thermal stability of model proteins lysozyme and myoglobin. Colloids Surf A Physicochem Eng Asp 2015. [DOI: 10.1016/j.colsurfa.2015.01.038] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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317
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Betancourt JE, Rivera JM. Tuning thermoresponsive supramolecular G-quadruplexes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:2095-2103. [PMID: 25641343 PMCID: PMC4863471 DOI: 10.1021/la504446k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Thermoresponsive systems are attractive due to their suitability for fundamental studies as well as their practical uses in a wide variety of applications. While much progress has been achieved using polymers, alternative strategies such as the use of well-defined nonpolymeric supramolecules are still underdeveloped. Here we report three 8-aryl-2'-deoxyguanosine derivatives (8ArGs) that self-assemble in aqueous media into precise thermoresponsive supramolecular G-quadruplexes (SGQs). We report the synthesis of such derivatives, studies of their isothermal self-assembly, and the thermally induced assembly to form higher-order meso-globular assemblies we term supramolecular hacky sacks (SHS). The lower critical solution temperature (LCST) that indicates the formation of the SHS was modulated by changing (a) intrinsic parameters (i.e., structure of the 8ArGs); (b) extrinsic parameters such as the salt used to promote the formation of the SGQ; and (c) supramolecular parameters such as the coassembly different 8ArGs to form heteromeric SGQs. Changes in the intrinsic parameters lead to LCST variations in the range of 28-59 °C. Modulating extrinsic parameters such as replacing KI with KSCN abolishes the thermoresponsive phenomenon whereas changing the cation from K(+) to Na(+) or adjusting the pH (in the range of 6-8) has negligible effects on the LCST. Modulating supramolecular parameters results in transition temperatures that are intermediate between those obtained by the respective homomeric SGQs, although the specific proportions of the subunits are critical in determining the reversibility of the process. Given the extensive applications of thermoresponsive polymers, the nonpolymeric supramolecular counterparts presented here may represent an attractive alternative for fundamental studies and biorelevant applications.
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318
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McAfee MS, Annunziata O. Effects of salting-in interactions on macromolecule diffusiophoresis and salt osmotic diffusion. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:1353-1361. [PMID: 25579202 DOI: 10.1021/la5046223] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Macromolecule diffusiophoresis (i.e., macromolecule migration induced by a salt concentration gradient) in water and salt osmotic diffusion (i.e., salt migration induced by a macromolecule concentration gradient) are two cross-diffusion mechanisms caused by macromolecule-salt interactions. We investigated the effect of salting-in interactions on the behavior of these two cross-diffusion mechanisms. Our results are distinct from those previously obtained in the case of salting-out interactions. Cross-diffusion was experimentally characterized by Rayleigh interferometry at 25 °C. Specifically, multicomponent diffusion coefficients were measured for a neutral polymer, polyethylene glycol (molar mass, 20 kg/mol), in aqueous solutions of three thiocyanate salts (NaSCN, KSCN, and NH₄SCN) as a function of salt concentration at low polymer concentration (0.5% w/w). Our results on salt osmotic diffusion, which were qualitatively different from those previously obtained for salting-out salts, were used to quantitatively characterize the strength of salting-in interactions. The behavior of polymer diffusiophoresis as a function of salt concentration and cation type reveals that polymer chains have an extrinsic negative charge, consistent with anion binding being the cause of salting-in interactions. To quantitatively examine the effect of anion binding on salt osmotic diffusion and polymer diffusiophoresis, we developed a theoretical model based on the linear laws of nonequilibrium thermodynamics for diffusion, the Scatchard binding model, and particle electrophoresis. This work contributes to the understanding of the multifaceted effects of molecular interactions on cross-diffusion mechanisms, salting-in interactions, and the Hofmeister series.
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Affiliation(s)
- Michele S McAfee
- Department of Chemistry, Texas Christian University , Fort Worth, Texas 76129, United States
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319
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Tse ECM, Barile CJ, Gewargis JP, Li Y, Zimmerman SC, Gewirth AA. Anion Transport through Lipids in a Hybrid Bilayer Membrane. Anal Chem 2015; 87:2403-9. [DOI: 10.1021/ac5043544] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Edmund C. M. Tse
- Department of Chemistry, University of Illinois at Urbana−Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Christopher J. Barile
- Department of Chemistry, University of Illinois at Urbana−Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - John P. Gewargis
- Department of Chemistry, University of Illinois at Urbana−Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Ying Li
- Department of Chemistry, University of Illinois at Urbana−Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Steven C. Zimmerman
- Department of Chemistry, University of Illinois at Urbana−Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Andrew A. Gewirth
- Department of Chemistry, University of Illinois at Urbana−Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
- International
Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, Fukuoka 812-8581, Japan
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320
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Effects of specific anions on the relationship between the ion-adsorption properties of sulfobetaine gel and its swelling behavior. POLYMER 2015. [DOI: 10.1016/j.polymer.2015.01.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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321
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Kumar A, Rani A, Venkatesu P. A comparative study of the effects of the Hofmeister series anions of the ionic salts and ionic liquids on the stability of α-chymotrypsin. NEW J CHEM 2015. [DOI: 10.1039/c4nj01596g] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Direct interactions between the anion and the catalytic amino acid residues lead to denaturation of CT.
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Affiliation(s)
- Awanish Kumar
- Department of Chemistry
- University of Delhi
- Delhi – 110 007
- India
| | - Anjeeta Rani
- Department of Chemistry
- University of Delhi
- Delhi – 110 007
- India
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322
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Rodríguez-Ropero F, van der Vegt NFA. On the urea induced hydrophobic collapse of a water soluble polymer. Phys Chem Chem Phys 2015; 17:8491-8. [DOI: 10.1039/c4cp05314a] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Polymer collapse despite cosolvent binding: solvation of extended coil conformations is entropically penalized, therefore stabilizing compact globular conformations in the coil-globule equilibrium of poly(N-isopropylacrylamide) in aqueous urea solution.
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Affiliation(s)
- Francisco Rodríguez-Ropero
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie and Center of Smart Interfaces
- Technische Universität Darmstadt
- Darmstadt
- Germany
| | - Nico F. A. van der Vegt
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie and Center of Smart Interfaces
- Technische Universität Darmstadt
- Darmstadt
- Germany
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323
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Zajforoushan Moghaddam S, Thormann E. Hofmeister effect of salt mixtures on thermo-responsive poly(propylene oxide). Phys Chem Chem Phys 2015; 17:6359-66. [DOI: 10.1039/c4cp05677a] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Hofmeister effect of salt mixtures is strongly dependent on composition of the mixture as well as absolute and relative concentration of the salts.
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Affiliation(s)
| | - Esben Thormann
- Department of Chemistry
- Technical University of Denmark
- 2800 Lyngby
- Denmark
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324
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Chen C, Huang C, Waluyo I, Weiss T, Pettersson LGM, Nilsson A. Long-range ion–water and ion–ion interactions in aqueous solutions. Phys Chem Chem Phys 2015; 17:8427-30. [DOI: 10.1039/c4cp04759a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using small-angle X-ray scattering (SAXS), we obtained direct experimental evidence on the structure of hydrated polyatomic anions, with hydration effects starkly different from those of cations (J. Chem. Phys., 2011, 134, 064513).
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Affiliation(s)
- Chen Chen
- Department of Chemistry
- Stanford University
- Stanford
- USA
- Sustainable Energy Through Catalysis (SUNCAT) Center for Interface Science and Catalysis
| | - Congcong Huang
- Stanford Synchrotron Radiation Lightsource
- SLAC National Accelerator Laboratory
- Menlo Park
- USA
| | - Iradwikanari Waluyo
- Department of Chemistry
- Stanford University
- Stanford
- USA
- Stanford Synchrotron Radiation Lightsource
| | - Thomas Weiss
- Stanford Synchrotron Radiation Lightsource
- SLAC National Accelerator Laboratory
- Menlo Park
- USA
| | - Lars G. M. Pettersson
- Department of Physics
- AlbaNova University Center
- Stockholm University
- SE-106 91 Stockholm
- Sweden
| | - Anders Nilsson
- Sustainable Energy Through Catalysis (SUNCAT) Center for Interface Science and Catalysis
- SLAC National Accelerator Laboratory
- Menlo Park
- USA
- Stanford Synchrotron Radiation Lightsource
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325
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Pica A, Graziano G. On the effect of sodium salts on the coil-to-globule transition of poly(N-isopropylacrylamide). Phys Chem Chem Phys 2015; 17:27750-7. [DOI: 10.1039/c5cp04094a] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Addition of sodium salts to water increases the density, thereby increasing the magnitude of the solvent-excluded volume effect and stabilizing the globule state of PNIPAM.
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Affiliation(s)
- Andrea Pica
- Dipartimento di Scienze Chimiche
- Università degli Studi di Napoli Federico II
- Complesso Universitario di Monte Sant'Angelo
- Naples
- Italy
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326
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Lesch V, Heuer A, Tatsis VA, Holm C, Smiatek J. Peptides in the presence of aqueous ionic liquids: tunable co-solutes as denaturants or protectants? Phys Chem Chem Phys 2015; 17:26049-53. [DOI: 10.1039/c5cp03838c] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We studied the stability of a small β-hairpin peptide under the influence of an aqueous 1-ethyl-3-methylimidazolium acetate solution via all-atom molecular dynamics simulations. A significant structure dependent binding of ACE to the peptide was identified as the main reason for the denaturation of the native conformation.
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Affiliation(s)
- Volker Lesch
- Institut für Physikalische Chemie
- Westfälische Wilhelms-Universität Münster
- D-48149 Münster
- Germany
| | - Andreas Heuer
- Institut für Physikalische Chemie
- Westfälische Wilhelms-Universität Münster
- D-48149 Münster
- Germany
| | - Vasileios A. Tatsis
- Institut für Physikalische Chemie
- Westfälische Wilhelms-Universität Münster
- D-48149 Münster
- Germany
| | - Christian Holm
- Institut für Computerphysik
- Universität Stuttgart
- D-70569 Stuttgart
- Germany
| | - Jens Smiatek
- Institut für Computerphysik
- Universität Stuttgart
- D-70569 Stuttgart
- Germany
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327
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Kashyap S, Jayakannan M. Super LCST thermo-responsive nanoparticle assembly for ATP binding through the Hofmeister effect. J Mater Chem B 2015; 3:1957-1967. [DOI: 10.1039/c4tb01844c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
ATP thermosensor: the first thermo-responsive super LCST amphiphile biomolecular probe was designed and developed for the detection of ATP based on the Hofmeister effect in aqueous medium.
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Affiliation(s)
- Smita Kashyap
- Department of Chemistry
- Indian Institute of Science Education and Research (IISER)
- Pune 411008
- India
| | - Manickam Jayakannan
- Department of Chemistry
- Indian Institute of Science Education and Research (IISER)
- Pune 411008
- India
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328
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Govinda V, Venkatesu P. A Comprehensive Experimental Study to Understand the Hofmeister Series of Anions of Aqueous Imidazolium-Based Ionic Liquids on Glycine Peptides. Ind Eng Chem Res 2014. [DOI: 10.1021/ie503736g] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Varadhi Govinda
- Department of Chemistry, University of Delhi, Delhi 110 007, India
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329
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Souza JCPD, Florenzano FH. Urea decreases specific ion effects on the LCST of PMMA-block-PDMAEMA aggregates. POLIMEROS 2014. [DOI: 10.1590/0104-1428.1592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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330
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King JD, Liu H, He G, Orf GS, Blankenship RE. Chemical activation of the cyanobacterial orange carotenoid protein. FEBS Lett 2014; 588:4561-5. [DOI: 10.1016/j.febslet.2014.10.024] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 10/20/2014] [Accepted: 10/22/2014] [Indexed: 11/29/2022]
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331
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Whitmer JK, Joshi AA, Carlton RJ, Abbott NL, de Pablo JJ. Surface Adsorption in Nonpolarizable Atomic Models. J Chem Theory Comput 2014; 10:5616-24. [DOI: 10.1021/ct5005406] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jonathan K. Whitmer
- Department
of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706-1691, United States
- Institute for
Molecular Engineering, Argonne National Laboratory, Argonne, Illinois 60439, United States
- Institute
for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Abhijeet A. Joshi
- Department
of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706-1691, United States
| | - Rebecca J. Carlton
- Department
of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706-1691, United States
| | - Nicholas L. Abbott
- Department
of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706-1691, United States
| | - Juan J. de Pablo
- Institute
for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
- Institute for Molecular
Engineering, Argonne National Laboratory, Argonne, Illinois 60439, United States
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332
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Jing B, Abot RCT, Zhu Y. Semihydrophobic Nanoparticle-Induced Disruption of Supported Lipid Bilayers: Specific Ion Effect. J Phys Chem B 2014; 118:13175-82. [DOI: 10.1021/jp5074945] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Benxin Jing
- Department of Chemical and
Biomolecular Engineering, University of Notre Dame, 182 Fitzpatrick
Hall, Notre
Dame, Indiana 46556, United States
| | - Rosary C. T. Abot
- Department of Chemical and
Biomolecular Engineering, University of Notre Dame, 182 Fitzpatrick
Hall, Notre
Dame, Indiana 46556, United States
| | - Yingxi Zhu
- Department of Chemical and
Biomolecular Engineering, University of Notre Dame, 182 Fitzpatrick
Hall, Notre
Dame, Indiana 46556, United States
- Department of Chemistry and
Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556, United States
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333
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An16-resilin: an advanced multi-stimuli-responsive resilin-mimetic protein polymer. Acta Biomater 2014; 10:4768-4777. [PMID: 25107894 DOI: 10.1016/j.actbio.2014.07.030] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 07/21/2014] [Accepted: 07/29/2014] [Indexed: 11/21/2022]
Abstract
Engineered protein polymers that display responsiveness to multiple stimuli are emerging as a promising class of soft material with unprecedented functionality. The remarkable advancement in genetic engineering and biosynthesis has created the opportunity for precise control over the amino acid sequence, size, structure and resulting functions of such biomimetic proteins. Herein, we describe the multi-stimuli-responsive characteristics of a resilin-mimetic protein, An16-resilin (An16), derived from the consensus sequence of resilin gene in the mosquito Anopheles gambiae. We demonstrate that An16 is an intrinsically disordered protein that displays unusual dual-phase thermal transition behavior along with responsiveness to pH, ion, light and humidity. Identifying the molecular mechanisms that allow An16 to sense and switch in response to varying environments furthers the ability to design intelligent biomacromolecules.
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334
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Ahmed M, Namboodiri V, Singh AK, Mondal JA. On the intermolecular vibrational coupling, hydrogen bonding, and librational freedom of water in the hydration shell of mono- and bivalent anions. J Chem Phys 2014; 141:164708. [DOI: 10.1063/1.4899070] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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335
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McAfee MS, Zhang H, Annunziata O. Amplification of salt-induced polymer diffusiophoresis by increasing salting-out strength. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:12210-12219. [PMID: 25245596 DOI: 10.1021/la503214b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The role of salting-out strength on (1) polymer diffusiophoresis from high to low salt concentration, and (2) salt osmotic diffusion from high to low polymer concentration was investigated. These two cross-diffusion phenomena were experimentally characterized by Rayleigh interferometry at 25 °C. Specifically, we report ternary diffusion coefficients for polyethylene glycol (molecular weight, 20 kg·mol(-1)) in aqueous solutions of several salts (NaCl, KCl, NH4Cl, CaCl2, and Na2SO4) as a function of salt concentration at low polymer concentration (0.5% w/w). We also measured polymer diffusion coefficients by dynamic light scattering in order to discuss the interpretation of these transport coefficients in the presence of cross-diffusion effects. Our cross-diffusion results, primarily those on salt osmotic diffusion, were utilized to extract N(w), the number of water molecules in thermodynamic excess around a macromolecule. This preferential-hydration parameter characterizes the salting-out strength of the employed salt. For chloride salts, changing cation has a small effect on N(w). However, replacing NaCl with Na2SO4 (i.e., changing anion) leads to a 3-fold increase in N(w), in agreement with cation and anion Hofmeister series. Theoretical arguments show that polymer diffusiophoresis is directly proportional to the difference N(w) - n(w), where n(w) is the number of water molecules transported by the migrating macromolecule. Interestingly, the experimental ratio, n(w)/N(w), was found to be approximately the same for all investigated salts. Thus, the magnitude of polymer diffusiophoresis is also proportional to salting-out strength as described by N(w). A basic hydrodynamic model was examined in order to gain physical insight on the role of n(w) in particle diffusiophoresis and explain the observed invariance of n(w)/N(w). Finally, we consider a steady-state diffusion problem to show that concentration gradients of strong salting-out agents such as Na2SO4 can produce large amplifications and depletions of macromolecule concentration. These effects may be exploited in self-assembly and adsorption processes.
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Affiliation(s)
- Michele S McAfee
- Contribution from the Department of Chemistry, Texas Christian University , Fort Worth, Texas 76129, United States
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336
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Carnegie R, Gibb CLD, Gibb BC. Anion complexation and the Hofmeister effect. Angew Chem Int Ed Engl 2014; 53:11498-500. [PMID: 25196481 PMCID: PMC4214138 DOI: 10.1002/anie.201405796] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Indexed: 11/10/2022]
Abstract
The (1)H NMR spectroscopic analysis of the binding of the ClO4(-) anion to the hydrophobic, concave binding site of a deep-cavity cavitand is presented. The strength of association between the host and the ClO4(-) anion is controlled by both the nature and concentration of co-salts in a manner that follows the Hofmeister series. A model that partitions this trend into the competitive binding of the co-salt anion to the hydrophobic pocket of the host and counterion binding to its external carboxylate groups successfully accounts for the observed changes in ClO4(-) affinity.
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Affiliation(s)
| | | | - B C. Gibb
- Department of Chemistry, Tulane University, New Orleans, LA 70118, USA
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337
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Shi J, Wang J. Interaction between Metal Cation and Unnatural Peptide Backbone Mediated by Polarized Water Molecules: Study of Infrared Spectroscopy and Computations. J Phys Chem B 2014; 118:12336-47. [DOI: 10.1021/jp504615f] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Jipei Shi
- Beijing
National Laboratory for Molecular Sciences; Molecular Reaction Dynamics
Laboratory, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Jianping Wang
- Beijing
National Laboratory for Molecular Sciences; Molecular Reaction Dynamics
Laboratory, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
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338
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Islam MN, Sarker KC, Sharker KK. Influence of Some Hofmeister Anions on the Krafft Temperature and Micelle Formation of Cetylpyridinium Bromide in Aqueous Solution. J SURFACTANTS DETERG 2014. [DOI: 10.1007/s11743-014-1642-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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339
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Bandyopadhyay D, Mohan S, Ghosh SK, Choudhury N. Molecular Dynamics Simulation of Aqueous Urea Solution: Is Urea a Structure Breaker? J Phys Chem B 2014; 118:11757-68. [DOI: 10.1021/jp505147u] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dibyendu Bandyopadhyay
- Heavy water Division and ‡Theoretical Chemistry
Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Sadhana Mohan
- Heavy water Division and ‡Theoretical Chemistry
Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Swapan K. Ghosh
- Heavy water Division and ‡Theoretical Chemistry
Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Niharendu Choudhury
- Heavy water Division and ‡Theoretical Chemistry
Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
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340
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Samukange V, Kamo M, Yasukawa K, Inouye K. Effects of salts on the interaction of 8-anilinonaphthalene 1-sulphonate and thermolysin. Biosci Biotechnol Biochem 2014; 78:1522-8. [PMID: 25209499 DOI: 10.1080/09168451.2014.923299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Neutral salts activate and stabilize thermolysin. In this study, to explore the mechanism, we analyzed the interaction of 8-anilinonaphthalene 1-sulphonate (ANS) and thermolysin by ANS fluorescence. At pH 7.5, the fluorescence of ANS increased and blue-shifted with increasing concentrations (0-2.0 μM) of thermolysin, indicating that the anilinonaphthalene group of ANS binds with thermolysin through hydrophobic interaction. ANS did not alter thermolysin activity. The dissociation constants (Kd) of the complex between ANS and thermolysin was 33 ± 2 μM at 0 M NaCl at pH 7.5, decreased with increasing NaCl concentrations, and reached 9 ± 3 μM at 4 M NaCl. The Kd values were not varied (31-34 μM) in a pH range of 5.5-8.5. This suggests that at high NaCl concentrations, Na(+) and/or Cl(-) ions bind with thermolysin and affect the binding of ANS with thermolysin. Our results also suggest that the activation and stabilization of thermolysin by NaCl are partially brought about by the binding of Na(+) and/or Cl(-) ions with thermolysin.
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Affiliation(s)
- Vimbai Samukange
- a Division of Food Science and Biotechnology, Graduate School of Agriculture , Kyoto University , Sakyo-ku , Japan
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341
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342
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Heyda J, Dzubiella J. Thermodynamic description of Hofmeister effects on the LCST of thermosensitive polymers. J Phys Chem B 2014; 118:10979-88. [PMID: 25147931 DOI: 10.1021/jp5041635] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cosolvent effects on protein or polymer collapse transitions are typically discussed in terms of a two-state free energy change that is strictly linear in cosolute concentration. Here we investigate in detail the nonlinear thermodynamic changes of the collapse transition occurring at the lower critical solution temperature (LCST) of the role-model polymer poly(N-isopropylacrylamide) [PNIPAM] induced by Hofmeister salts. First, we establish an equation, based on the second-order expansion of the two-state free energy in concentration and temperature space, which excellently fits the experimental LCST curves and enables us to directly extract the corresponding thermodynamic parameters. Linear free energy changes, grounded on generic excluded-volume mechanisms, are indeed found for strongly hydrated kosmotropes. In contrast, for weakly hydrated chaotropes, we find significant nonlinear changes related to higher order thermodynamic derivatives of the preferential interaction parameter between salts and polymer. The observed non-monotonic behavior of the LCST can then be understood from a not yet recognized sign change of the preferential interaction parameter with salt concentration. Finally, we find that solute partitioning models can possibly predict the linear free energy changes for the kosmotropes, but fail for chaotropes. Our findings cast strong doubt on their general applicability to protein unfolding transitions induced by chaotropes.
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Affiliation(s)
- Jan Heyda
- Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin , Hahn-Meitner Platz 1, 14109 Berlin, Germany
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343
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Salis A, Ninham BW. Models and mechanisms of Hofmeister effects in electrolyte solutions, and colloid and protein systems revisited. Chem Soc Rev 2014; 43:7358-77. [PMID: 25099516 DOI: 10.1039/c4cs00144c] [Citation(s) in RCA: 382] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Specific effects of electrolytes have posed a challenge since the 1880's. The pioneering work was that of Franz Hofmeister who studied specific salt induced protein precipitation. These effects are the rule rather the exception and are ubiquitous in chemistry and biology. Conventional electrostatic theories (Debye-Hückel, DLVO, etc.) cannot explain such effects. Over the past decades it has been recognised that additional quantum mechanical dispersion forces with associated hydration effects acting on ions are missing from theory. In parallel Collins has proposed a phenomenological set of rules (the law of matching water affinities, LMWA) which explain and bring to order the order of ion-ion and ion-surface site interactions at a qualitative level. The two approaches appear to conflict. Although the need for inclusion of quantum dispersion forces in one form or another is not questioned, the modelling has often been misleading and inappropriate. It does not properly describe the chemical nature (kosmotropic/chaotropic or hard/soft) of the interacting species. The success of the LMWA rules lies in the fact that they do. Here we point to the way that the two apparently opposing approaches might be reconciled. Notwithstanding, there are more challenges, which deal with the effect of dissolved gas and its connection to 'hydrophobic' interactions, the problem of water at different temperatures and 'water structure' in the presence of solutes. They take us to another dimension that requires the rebuilding of theoretical foundations.
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Affiliation(s)
- Andrea Salis
- Department of Chemical and Geological Science, University of Cagliari, Italy and CSGI.
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344
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Rakel N, Baum M, Hubbuch J. Moving through three-dimensional phase diagrams of monoclonal antibodies. Biotechnol Prog 2014; 30:1103-13. [PMID: 25044865 DOI: 10.1002/btpr.1947] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Revised: 06/14/2014] [Indexed: 11/12/2022]
Abstract
Protein phase behavior characterization is a multivariate problem due to the high amount of influencing parameters and the diversity of the proteins. Single influences on the protein are not understood and fundamental knowledge remains to be obtained. For this purpose, a systematic screening method was developed to characterize the influence of fluid phase conditions on the phase behavior of proteins in three-dimensional phase diagrams. This approach was applied to three monoclonal antibodies to investigate influences of pH, protein and salt concentrations, with five different salts being tested. Although differences exist between the antibodies, this extensive study confirmed the general applicability of the Hofmeister series over the broad parameter range analyzed. The influence of the different salts on the aggregation (crystallization and precipitation) probability was described qualitatively using this Hofmeister series, with a differentiation between crystallization and precipitation being impossible, however.
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Affiliation(s)
- Natalie Rakel
- Biomolecular Separation Engineering, Institute of Engineering in Life Sciences, Karlsruhe Institute of Technology, Engler-Bunte-Ring 1, 76131, Karlsruhe, Germany
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345
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Budkov YA, Kolesnikov AL, Georgi N, Kiselev MG. A statistical theory of cosolvent-induced coil-globule transitions in dilute polymer solution. J Chem Phys 2014; 141:014902. [DOI: 10.1063/1.4884958] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Yu. A. Budkov
- Institute of Solution Chemistry of the Russian Academy of Sciences, Ivanovo, Russia
| | - A. L. Kolesnikov
- Ivanovo State University, Ivanovo, Russia
- Institut für Nichtklassische Chemie e.V., Universitat Leipzig, Leipzig, Germany
| | - N. Georgi
- Max Planck Institute for Mathematics in the Sciences, Leipzig, Germany
| | - M. G. Kiselev
- Institute of Solution Chemistry of the Russian Academy of Sciences, Ivanovo, Russia
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346
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Pluhařová E, Baer MD, Mundy CJ, Schmidt B, Jungwirth P. Aqueous Cation-Amide Binding: Free Energies and IR Spectral Signatures by Ab Initio Molecular Dynamics. J Phys Chem Lett 2014; 5:2235-2240. [PMID: 26279540 DOI: 10.1021/jz500976m] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Understanding specific ion effects on proteins remains a considerable challenge. N-methylacetamide serves as a useful proxy for the protein backbone that can be well characterized both experimentally and theoretically. The spectroscopic signatures in the amide I band reflecting the strength of the interaction of alkali cations and alkaline earth dications with the carbonyl group remain difficult to assign and controversial to interpret. Herein, we directly compute the infrared (IR) shifts corresponding to the binding of either sodium or calcium to aqueous N-methylacetamide using ab initio molecular dynamics simulations. We show that the two cations interact with aqueous N-methylacetamide with different affinities and in different geometries. Because sodium exhibits a weak interaction with the carbonyl group, the resulting amide I band is similar to an unperturbed carbonyl group undergoing aqueous solvation. In contrast, the stronger calcium binding results in a clear IR shift with respect to N-methylacetamide in pure water.
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Affiliation(s)
- Eva Pluhařová
- †Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, 16610, Prague 6 160 00, Czech Republic
| | - Marcel D Baer
- ‡Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Christopher J Mundy
- ‡Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Burkhard Schmidt
- §Institut für Mathematik, Freie Universität Berlin, Arnimallee 6, D-14195 Berlin, Germany
| | - Pavel Jungwirth
- †Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, 16610, Prague 6 160 00, Czech Republic
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347
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Rodríguez-Ropero F, van der Vegt NFA. Direct Osmolyte–Macromolecule Interactions Confer Entropic Stability to Folded States. J Phys Chem B 2014; 118:7327-34. [DOI: 10.1021/jp504065e] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Francisco Rodríguez-Ropero
- Center of Smart Interfaces, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, 64287, Darmstadt, Germany
| | - Nico F. A. van der Vegt
- Center of Smart Interfaces, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, 64287, Darmstadt, Germany
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348
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Liu X, Li H, Li R, Xie D, Ni J, Wu L. Strong non-classical induction forces in ion-surface interactions: general origin of Hofmeister effects. Sci Rep 2014; 4:5047. [PMID: 24854224 PMCID: PMC7365329 DOI: 10.1038/srep05047] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 05/06/2014] [Indexed: 11/25/2022] Open
Abstract
Hofmeister effects continue to defy all-encompassing theories and their origin
is still a matter of debate. We observed strong Hofmeister effects in
Ca2+/Na+ exchange on a
permanently charged surface over a wide range of ionic strengths. They could not be
attributed to dispersion forces, classical induction forces, ionic size, or
hydration effects. We demonstrated that another stronger force was active in the
ion-surface interactions and which would create Hofmeister effects in general. The
strength of this force was up to 104 times that of the
classical induction force and could be comparable to the Coulomb force. Coulomb,
dispersion and hydration effects appeared to be interwined to affect the force. The
presence of the observed strong non-classical induction force implied that energies
of non-valence electrons of ions/atoms at the interface might be heavily
underestimated in current theories and possibly just those underestimated energies
of non-valence electrons determined Hofmeister effects.
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Affiliation(s)
- Xinmin Liu
- Chongqing key laboratory of soil multi-scale interfacial process, College of Resources and Environment, Southwest University, Chongqing 400715, CHINA
| | - Hang Li
- Chongqing key laboratory of soil multi-scale interfacial process, College of Resources and Environment, Southwest University, Chongqing 400715, CHINA
| | - Rui Li
- Chongqing key laboratory of soil multi-scale interfacial process, College of Resources and Environment, Southwest University, Chongqing 400715, CHINA
| | - Deti Xie
- Chongqing key laboratory of soil multi-scale interfacial process, College of Resources and Environment, Southwest University, Chongqing 400715, CHINA
| | - Jiupai Ni
- Chongqing key laboratory of soil multi-scale interfacial process, College of Resources and Environment, Southwest University, Chongqing 400715, CHINA
| | - Laosheng Wu
- Department of Environmental Sciences, University of California, Riverside, CA 92501, USA
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349
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Chen J, Spěváček J, Hanyková L. NMR Methods to Study Effects of Additives on Phase Separation of Thermoresponsive Polymer. ACTA ACUST UNITED AC 2014. [DOI: 10.1002/masy.201300130] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jianqiang Chen
- Environmental Engineering Department; Nanjing Forestry University; Longpan Rd. 159 210037 Nanjing P.R. China
| | - Jiří Spěváček
- Institute of Macromolecular Chemistry; Academy of Sciences of the Czech Republic; Heyrovský Sq. 2 162 06 Prague 6 Czech Republic
| | - Lenka Hanyková
- Faculty of Mathematics and Physics; Charles University; V Holešovičkách 2 180 00 Prague 8 Czech Republic
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350
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Khvostichenko DS, Ng JJD, Perry SL, Menon M, Kenis PJA. Effects of detergent β-octylglucoside and phosphate salt solutions on phase behavior of monoolein mesophases. Biophys J 2014; 105:1848-59. [PMID: 24138861 DOI: 10.1016/j.bpj.2013.09.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 08/16/2013] [Accepted: 09/06/2013] [Indexed: 10/26/2022] Open
Abstract
Using small-angle x-ray scattering (SAXS), we investigated the phase behavior of mesophases of monoolein (MO) mixed with additives commonly used for the crystallization of membrane proteins from lipidic mesophases. In particular, we examined the effect of sodium and potassium phosphate salts and the detergent β-octylglucoside (βOG) over a wide range of compositions relevant for the crystallization of membrane proteins in lipidic mesophases. We studied two types of systems: 1), ternary mixtures of MO with salt solutions above the hydration boundary; and 2), quaternary mixtures of MO with βOG and salt solutions over a wide range of hydration conditions. All quaternary mixtures showed highly regular lyotropic phase behavior with the same sequence of phases (Lα, Ia3d, and Pn3m) as MO/water mixtures at similar temperatures. The effects of additives in quaternary systems agreed qualitatively with those found in ternary mixtures in which only one additive is present. However, quantitative differences in the effects of additives on the lattice parameters of fully hydrated mesophases were found between ternary and quaternary mixtures. We discuss the implications of these findings for mechanistic investigations of membrane protein crystallization in lipidic mesophases and for studies of the suitability of precipitants for mesophase-based crystallization methods.
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Affiliation(s)
- Daria S Khvostichenko
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois
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