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Arumughan V, Özeren H, Hedenqvist M, Skepö M, Nypelö T, Hasani M, Larsson A. Anion-Specific Adsorption of Carboxymethyl Cellulose on Cellulose. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:15014-15021. [PMID: 37817605 PMCID: PMC10601536 DOI: 10.1021/acs.langmuir.3c01924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 09/18/2023] [Indexed: 10/12/2023]
Abstract
Integration of fiber modification step with a modern pulp mill is a resource efficient way to produce functional fibers. Motivated by the need to integrate polymer adsorption with the current pulping system, anion-specific effects in carboxymethylcellulose (CMC) adsorption have been studied. The QCM-D adsorption experiments revealed that CMC adsorption to the cellulose model surface is prone to anion-specific effects. A correlation was observed between the adsorbed CMC and the degree of hydration of the co-ions present in the magnesium salts. The presence of a chaotropic co-ion such as nitrate increased the adsorption of CMC on cellulose compared to the presence of the kosmotropic sulfate co-ion. However, anion-specificity was not significant in the case of salts containing zinc cations. The hydration of anions determines the distribution of the ions at the interface. Chaotropic ions, such as nitrates, are likely to be distributed near the chaotropic cellulose surface, causing changes in the ordering of water molecules and resulting in greater entropy gain once released from the surface, thus increasing CMC adsorption.
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Affiliation(s)
- Vishnu Arumughan
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, SE-41296 Gothenburg, Sweden
- AvanCell, Chalmers University
of Technology, SE-41296 Gothenburg, Sweden
| | - Hüsamettin
Deniz Özeren
- School
of Engineering Sciences in Chemistry, Biotechnology and Health, Polymeric
Materials Division, Fiber and Polymer Technology, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Mikael Hedenqvist
- School
of Engineering Sciences in Chemistry, Biotechnology and Health, Polymeric
Materials Division, Fiber and Polymer Technology, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
- Wallenberg
Wood Science Center, KTH Royal Institute
of Technology, SE-100 44 Stockholm, Sweden
- FibRe
Vinnova Competence Center, KTH Royal Institute
of Technology, SE-100 44 Stockholm, Sweden
| | - Marie Skepö
- Division
of Theoretical Chemistry, Lund University, P. O. Box 124, SE-221 00 Lund, Sweden
| | - Tiina Nypelö
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, SE-41296 Gothenburg, Sweden
- Wallenberg
Wood Science Center, Chalmers University
of Technology, SE-41296 Gothenburg, Sweden
| | - Merima Hasani
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, SE-41296 Gothenburg, Sweden
- AvanCell, Chalmers University
of Technology, SE-41296 Gothenburg, Sweden
- Wallenberg
Wood Science Center, Chalmers University
of Technology, SE-41296 Gothenburg, Sweden
| | - Anette Larsson
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, SE-41296 Gothenburg, Sweden
- AvanCell, Chalmers University
of Technology, SE-41296 Gothenburg, Sweden
- Wallenberg
Wood Science Center, Chalmers University
of Technology, SE-41296 Gothenburg, Sweden
- FibRe
Vinnova Competence Center, Chalmers University
of Technology, SE-41296 Gothenburg, Sweden
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FTIR Spectroscopy Study of the Secondary Structure Changes in Human Serum Albumin and Trypsin under Neutral Salts. Biomolecules 2020; 10:biom10040606. [PMID: 32295172 PMCID: PMC7226448 DOI: 10.3390/biom10040606] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/27/2020] [Accepted: 03/30/2020] [Indexed: 11/24/2022] Open
Abstract
The effect of neutral salts on protein conformation was first analyzed by Hofmeister in 1888, however, even today this phenomenon is not completely understood. To clarify this effect, we studied changes in the secondary structure of two proteins: human serum albumin with predominantly α-helical structure and porcine pancreas β-trypsin with the typical β-structural arrangement in aqueous solutions of neutral salts (KSCN, KCl, (NH4)2SO4). The changes in the secondary structure were studied at 23 °C and 80 °C by using the second derivative deconvolution method of the IR spectra. Our results demonstrated that the ability of the salts to stabilize/destabilize these two proteins correlates with the Hofmeister series of ions. At the same time, some exceptions were also observed. The destabilization of the native structures of both α-helical albumin and β-structural trypsin upon interaction with neutral salts leads to the formation of intermolecular β-sheets typical for amyloid fibrils or amorphous aggregates. Thus, our quantitative FTIR-spectroscopy analysis allowed us to further clarify the mechanisms and complexity of the neutral salt actions on protein structures which may lead to strategies preventing unwelcome misfolding of proteins.
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Abstract
AbstractThe strong, long-range electrostatic forces described by Coulomb's law disappear for ions in water, and the behavior of these ions is instead controlled by their water affinity – a weak, short-range force which arises from their charge density. This was established experimentally in the mid-1980s by size-exclusion chromatography on carefully calibrated Sephadex®G-10 (which measures the effective volume and thus the water affinity of an ion) and by neutron diffraction with isotopic substitution (which measures the density and orientation of water molecules near the diffracting ion and thus its water affinity). These conclusions have been confirmed more recently by molecular dynamics simulations, which explicitly model each individual water molecule. This surprising change in force regime occurs because the oppositely charged ions in aqueous salt solutions exist functionally as ion pairs (separated by 0, 1 or 2 water molecules) as has now been shown by dielectric relaxation spectroscopy; this cancels out the strong long-range electrostatic forces and allows the weak, short-range water affinity effects to come to the fore. This microscopic structure of aqueous salt solutions is not captured by models utilizing a macroscopic dielectric constant. Additionally, the Law of Matching Water Affinity, first described in 1997 and 2004, establishes that contact ion pair formation is controlled by water affinity and is a major determinant of the solubility of charged species since only a net neutral species can change phases.
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Willott JD, Humphreys BA, Webber GB, Wanless EJ, de Vos WM. Combined Experimental and Theoretical Study of Weak Polyelectrolyte Brushes in Salt Mixtures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:2709-2718. [PMID: 30661354 PMCID: PMC6407915 DOI: 10.1021/acs.langmuir.8b03838] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 01/07/2019] [Indexed: 05/30/2023]
Abstract
The swelling behavior of a hydrophobic poly(2diisopropylamino)ethyl methacrylate (PDPA) brush immersed in aqueous solutions of single and mixed salts has been investigated using ellipsometry and numerical self-consistent field (nSCF) theory. As a function of solution ionic strength, the osmotic and salted brush regimes of weak polyelectrolyte brushes as well as substantial specific anion effects in the presence of K+ salts of Cl-, NO3-, and SCN- are found. For solutions containing mixtures of NO3- and Cl-, the brush swelling is the same as one would expect on the basis of the concentration-weighted average of the brush behavior in the single salt solutions. However, in mixtures of SCN- and Cl-, the swelling response is more complicated and substantial divergence from ideal behavior is observed. Mean-field theory shows excellent qualitative agreement with the ellipsometry findings. nSCF reveals that for the SCN-/Cl- cases the swelling behavior of the PDPA brush most likely arises from the predominant localization of the weakly hydrated SCN- within the brush compared to the more strongly hydrated Cl-.
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Affiliation(s)
- Joshua D. Willott
- Membrane
Science and Technology, Mesa+ Institute for Nanotechnology, University of Twente, Enschede 7500 AE, The Netherlands
| | - Ben A. Humphreys
- Priority
Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Grant B. Webber
- Priority
Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Erica J. Wanless
- Priority
Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Wiebe M. de Vos
- Membrane
Science and Technology, Mesa+ Institute for Nanotechnology, University of Twente, Enschede 7500 AE, The Netherlands
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Fernández–d'Arlas B, Huertos MÁ, Müller AJ. Ion-macromolecule interactions studied with model polyurethanes. J Colloid Interface Sci 2018; 509:102-112. [DOI: 10.1016/j.jcis.2017.08.099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 08/29/2017] [Accepted: 08/30/2017] [Indexed: 11/25/2022]
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6
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Metzger L, Kind M. The influence of mixing on fast precipitation processes – A coupled 3D CFD-PBE approach using the direct quadrature method of moments (DQMOM). Chem Eng Sci 2017. [DOI: 10.1016/j.ces.2016.07.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Tong JG, Wei ZY, Yang HL, Yang ZY, Chen Y. Study on the phase transition behaviors of thermoresponsive hyperbranched polyampholytes in water. POLYMER 2016. [DOI: 10.1016/j.polymer.2015.12.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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8
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Huettmann H, Zich S, Berkemeyer M, Buchinger W, Jungbauer A. Design of industrial crystallization of interferon gamma: Phase diagrams and solubility curves. Chem Eng Sci 2015. [DOI: 10.1016/j.ces.2014.12.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Willott JD, Murdoch TJ, Humphreys BA, Edmondson S, Wanless EJ, Webber GB. Anion-specific effects on the behavior of pH-sensitive polybasic brushes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:3707-3717. [PMID: 25768282 DOI: 10.1021/acs.langmuir.5b00116] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The anion-specific solvation and conformational behavior of weakly basic poly(2-dimethylamino)ethyl methacrylate (poly(DMA)), poly(2-diethylamino)ethyl methacrylate (poly(DEA)), and poly(2-diisopropylamino)ethyl methacrylate (poly(DPA)) brushes, with correspondingly increasing inherent hydrophobicity, have been investigated using in situ ellipsometric and quartz crystal microbalance with dissipation (QCM-D) measurements. In the osmotic brush regime, as the initial low concentration of salt is increased, the brushes osmotically swell by the uptake of solvent as they become charged and the attractive hydrophobic inter- and intrachain interactions are overcome. With increased ionic strength, the brushes move into the salted brush regime where they desolvate and collapse as their electrostatic charge is screened. Here, as the brushes collapse, they transition to more uniform and rigid conformations, which dissipate less energy, than similarly solvated brushes at lower ionic strength. Significantly, in these distinct regimes brush behavior is not only ionic strength dependent but is also influenced by the nature of the added salt based on its position in the well-known Hofmeister or lyotropic series, with potassium acetate, nitrate, and thiocyanate investigated. The strongly kosmotropic acetate anions display low affinity for the hydrophobic polymers, and largely unscreened electrosteric repulsions allow the brushes to remain highly solvated at higher acetate concentrations. The mildly chaotropic nitrate and strongly chaotropic thiocyanate anions exhibit a polymer hydrophobicity-dependent affinity for the brushes. Increasing thiocyanate concentration causes the brushes to collapse at lower ionic strength than for the other two anions. This study of weak polybasic brushes demonstrates the importance of all ion, solvent, and polymer interactions.
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Affiliation(s)
- Joshua D Willott
- †Priority Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Timothy J Murdoch
- †Priority Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Ben A Humphreys
- †Priority Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Steve Edmondson
- ‡School of Materials, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Erica J Wanless
- †Priority Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Grant B Webber
- †Priority Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
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11
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Tischer A, Lilie H, Auton M, Lange C. Oxidative refolding of rPA in l
-ArgHCl and in ionic liquids: A correlation between hydrophobicity, salt effects, and refolding yield. Biopolymers 2014; 101:1129-40. [DOI: 10.1002/bip.22518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Revised: 05/09/2014] [Accepted: 06/10/2014] [Indexed: 12/17/2022]
Affiliation(s)
- Alexander Tischer
- Division of Hematology, Departments of Internal Medicine; Biochemistry and Molecular Biology, Mayo Clinic; Rochester MN
| | - Hauke Lilie
- Institut für Biochemie und Biotechnologie; Martin-Luther-Universität Halle-Wittenberg; Kurt-Mothes-Str. 3 06120 Halle (Saale) Germany
| | - Matthew Auton
- Division of Hematology, Departments of Internal Medicine; Biochemistry and Molecular Biology, Mayo Clinic; Rochester MN
| | - Christian Lange
- Scil Proteins GmbH; Heinrich Damerow Str. 1 06120 Halle (Saale) Germany
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12
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Abstract
AbstractEffects of chlorides of univalent (LiCl, NaCl, KCl), bivalent (MgCl2, BaCl2) and trivalent (AlCl3) metals at different concentration (0.001–0.1 M) on the behavior of nanosilica A-200 (0.5–5 wt.%) in aqueous media are analyzed using photon correlation spectroscopy (particle size distribution, PSD), electrophoresis (zeta potential ζ), potentiometric titration (surface charge density), and estimation of screening length of primary particles and their aggregates. The zeta potential and the PSD are affected by silica content, pH, and concentration and type of dissolved salts. Smaller but more strongly hydrated Li+ cations caused stronger nonlinear dependences of the zeta potential on pH and salt content than Na+ or K+. This nonlinearity is much stronger at a lower content of silica (0.5–1 wt.%) than at C
A-200 = 2.5 or 5 wt.%. At a high concentration of nanosilica (5 wt.%) the effect of K+ ions causes stronger diminution of the negative value of the zeta potential due to better adsorption of larger cations. Therefore, the influence of K+ on increasing screening length is stronger than that of Na+ for both primary nanoparticles and their aggregates. A similar difference in the ζ values is observed for different in size cations Ba2+ and Mg2+.
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Cecchi T, Marcotulli F. Chromatography and the hundred year mystery of inorganic ions at aqueous interfaces: adsorption of inorganic ions at the Porous Graphitic Carbon Aqueous Interface follows the Hofmeister series. J Chromatogr A 2013; 1314:106-14. [PMID: 24075459 DOI: 10.1016/j.chroma.2013.09.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 09/03/2013] [Accepted: 09/04/2013] [Indexed: 10/26/2022]
Abstract
Many physical phenomena are affected by the structure of water interfaces, yet it remains an active and controversial subject. A great deal of recent theoretical endeavour and computer simulations question the validity of the Onsager Samaras theory of the ion-free interface between an electrolyte solution and an hydrophobic surface. Experimental results play a crucial role in assessing the legitimacy of the theories. Experimental data are scarce, while simulation results suggest an increasing surface affinity of ions with increasing chaotropic character, in dramatic contradiction to the classical view. Chromatography is a powerful separative technique, but we originally used it as a tool to detect the adsorption of chloride electrolytes and sodium electrolytes, strongly expected to shun any dielectric boundary, onto an hydrophobic surface, and to rank ions according to their adsorbophilicities. Frontal analysis gave unequivocal experimental evidence to this unexpected phenomenon and it was used to quantify it. The infinite dilution equilibrium constants for adsorption of kosmotropes and chaotropes onto the interface were obtained and contrasted to the Jones-Dole B viscosity coefficients, that is a common quantifier of the Hofmeister effect. It is clear that (i) the more chaotropic the ion is, the more it contributes to the global adsorbophilicity of the electrolyte; (ii) the influence of the variable anion is more than twofold that of the variable cation, thereby confirming a robust observation in many other physical systems. Standard free energy of adsorption for each electrolyte was calculated and its reliability was commented upon. The central issue in this paper is the effective and ascertained adsorption of electrolytes onto an hydrophobic surface and the fact that the adsorbophilicity of an electrolyte may be inferred from its position in the Hofmeister series.
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Affiliation(s)
- Teresa Cecchi
- Accademia Delle Scienze dell'istituto di Bologna, Via Zamboni, 31, 40126 Bologna, Italy.
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14
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Collins KD. Why continuum electrostatics theories cannot explain biological structure, polyelectrolytes or ionic strength effects in ion–protein interactions. Biophys Chem 2012; 167:43-59. [DOI: 10.1016/j.bpc.2012.04.002] [Citation(s) in RCA: 169] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 04/10/2012] [Accepted: 04/10/2012] [Indexed: 01/13/2023]
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15
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Gao R, van Halsema F, Temminghoff E, van Leeuwen H, van Valenberg H, Eisner M, van Boekel M. Modelling ion composition in simulated milk ultrafiltrate (SMUF) II. Influence of pH, ionic strength and polyphosphates. Food Chem 2010. [DOI: 10.1016/j.foodchem.2010.03.038] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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16
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Trompette J, Arurault L, Fontorbes S, Massot L. Influence of the anion specificity on the electrochemical corrosion of anodized aluminum substrates. Electrochim Acta 2010. [DOI: 10.1016/j.electacta.2009.12.063] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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17
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Hou Y, Yu C, Liu G, Ngai T, Zhang G. Effects of Anions on the Aggregation of Charged Microgels. J Phys Chem B 2010; 114:3799-803. [DOI: 10.1021/jp9121694] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yi Hou
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, China, and Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
| | - Changqian Yu
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, China, and Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
| | - Guangming Liu
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, China, and Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
| | - To Ngai
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, China, and Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
| | - Guangzhao Zhang
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, China, and Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
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18
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Bommarius AS, Broering JM. Established and novel tools to investigate biocatalyst stability. BIOCATAL BIOTRANSFOR 2009. [DOI: 10.1080/10242420500218877] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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19
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Hetényi A, Fülöp L, Martinek TA, Wéber E, Soós K, Penke B. Ligand-Induced Flocculation of Neurotoxic Fibrillar Aβ(1–42) by Noncovalent Crosslinking. Chembiochem 2008; 9:748-57. [DOI: 10.1002/cbic.200700351] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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20
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Klausen TK, Hougaard C, Hoffmann EK, Pedersen SF. Cholesterol modulates the volume-regulated anion current in Ehrlich-Lettre ascites cells via effects on Rho and F-actin. Am J Physiol Cell Physiol 2006; 291:C757-71. [PMID: 16687471 DOI: 10.1152/ajpcell.00029.2006] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The mechanisms controlling the volume-regulated anion current (VRAC) are incompletely elucidated. Here, we investigate the modulation of VRAC by cellular cholesterol and the potential involvement of F-actin, Rho, Rho kinase, and phosphatidylinositol-(4,5)-bisphosphate [PtdIns(4,5)P2] in this process. In Ehrlich-Lettre ascites (ELA) cells, a current with biophysical and pharmacological properties characteristic of VRAC was activated by hypotonic swelling. A 44% increase in cellular cholesterol content had no detectable effects on F-actin organization or VRAC activity. A 47% reduction in cellular cholesterol content increased cortical and stress fiber-associated F-actin content in swollen cells. Cholesterol depletion increased VRAC activation rate and maximal current after a modest (15%), but not after a severe (36%) reduction in extracellular osmolarity. The cholesterol depletion-induced increase in maximal VRAC current was prevented by F-actin disruption using latrunculin B (LB), while the current activation rate was unaffected by LB, but dependent on Rho kinase. Rho activity was decreased by ∼20% in modestly, and ∼50% in severely swollen cells. In modestly swollen cells, this reduction was prevented by cholesterol depletion, which also increased isotonic Rho activity. Thrombin, which stimulates Rho and causes actin polymerization, potentiated VRAC in modestly swollen cells. VRAC activity was unaffected by inclusion of a water-soluble PtdIns(4,5)P2analogue or a PtdIns(4,5)P2-blocking antibody in the pipette, or neomycin treatment to sequester PtdIns(4,5)P2. It is suggested that in ELA cells, F-actin and Rho-Rho kinase modulate VRAC magnitude and activation rate, respectively, and that cholesterol depletion potentiates VRAC at least in part by preventing the hypotonicity-induced decrease in Rho activity and eliciting actin polymerization.
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Affiliation(s)
- Thomas Kjaer Klausen
- Department of Biochemistry, Institute of Molecular Biology and Physiology, University of Copenhagen, Copenhagen, Denmark
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21
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Narinesingh D, Pope A, Ngo TT. Flow Injection Ahalysis of Human Serum Albumin Using a Stabilized, Immobilized Cibacron Blue Support. ANAL LETT 2006. [DOI: 10.1080/00032719208018246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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22
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Broering JM, Bommarius AS. Evaluation of Hofmeister Effects on the Kinetic Stability of Proteins. J Phys Chem B 2005; 109:20612-9. [PMID: 16853668 DOI: 10.1021/jp053618+] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dissolved salts are known to affect properties of proteins in solution including solubility and melting temperature, and the effects of dissolved salts can be ranked qualitatively by the Hofmeister series. We seek a quantitative model to predict the effects of salts in the Hofmeister series on the deactivation kinetics of enzymes. Such a model would allow for a better prediction of useful biocatalyst lifetimes or an improved estimation of protein-based pharmaceutical shelf life. Here we consider a number of salt properties that are proposed indicators of Hofmeister effects in the literature as a means for predicting salt effects on the deactivation of horse liver alcohol dehydrogenase (HL-ADH), alpha-chymotrypsin, and monomeric red fluorescent protein (mRFP). We find that surface tension increments are not accurate predictors of salt effects but find a common trend between observed deactivation constants and B-viscosity coefficients of the Jones-Dole equation, which are indicative of ion hydration. This trend suggests that deactivation constants (log k(d,obs)) vary linearly with chaotropic B-viscosity coefficients but are relatively unchanged in kosmotropic solutions. The invariance with kosmotropic B-viscosity coefficients suggests the existence of a minimum deactivation constant for proteins. Differential scanning calorimetry is used to measure protein melting temperatures and thermodynamic parameters, which are used to calculate the intrinsic irreversible deactivation constant. We find that either the protein unfolding rate or the rate of intrinsic irreversible deactivation can control the observed deactivation rates.
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Affiliation(s)
- James M Broering
- School of Chemical & Biomolecular Engineering, School of Chemistry and Biochemistry, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, GA 30332-0363, USA
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23
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Collins KD. Ion hydration: Implications for cellular function, polyelectrolytes, and protein crystallization. Biophys Chem 2005; 119:271-81. [PMID: 16213082 DOI: 10.1016/j.bpc.2005.08.010] [Citation(s) in RCA: 286] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Revised: 08/30/2005] [Accepted: 08/31/2005] [Indexed: 11/25/2022]
Abstract
Only oppositely charged ions with matching absolute free energies of hydration spontaneously form inner sphere ion pairs in free solution [K.D.Collins, Ions from the Hofmeister series and osmolytes: effects on proteins in solution and in the crystallization process, Methods 34 (2004) 300-311.]. We approximate this with a Law of Matching Water Affinities which is used to examine the issues of (1) how ions are selected to be compatible with the high solubility requirements of cytosolic components; (2) how cytosolic components tend to interact weakly, so that association or dissociation can be driven by environmental signals; (3) how polyelectrolytes (nucleic acids) differ from isolated charges (in proteins); (4) how ions, osmolytes and polymers are used to crystallize proteins; and (5) how the "chelate effect" is used by macromolecules to bind ions at specific sites even when there is a mismatch in water affinity between the ion and the macromolecular ligands.
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Affiliation(s)
- Kim D Collins
- Department of Biochemistry and Molecular Biology, University of Maryland Medical School, 108 N. Greene Street, Baltimore, MD 21201-1503, USA.
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Sedlák E, Žoldák G, Antalı́k M, Sprinzl M. Thermodynamic properties of nucleotide-free EF-Tu from Thermus thermophilus in the presence of low-molecular weight effectors of its GTPase activity. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s0167-4838(02)00270-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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25
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Stellwagen E. Dye affinity chromatography. CURRENT PROTOCOLS IN PROTEIN SCIENCE 2001; Chapter 9:Unit 9.2. [PMID: 18429211 DOI: 10.1002/0471140864.ps0902s00] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Dye affinity chromatography is a protein purification procedure based on the high affinity of immobilized dyes for the binding sites on many proteins. It is a rapid, inexpensive, and versatile method that is applicable to the purification of crude cellular extracts. This unit presents protocol for the three types of dye affinity chromatography: negative chromatography, positive chromatography, and tandem chromatography. An initial protocol describes a chromatographic procedure in which a small volume of the protein mixture to be purified is applied to a series of miniature columns, each containing a different immobilized dye. Analysis of the flowthrough and bound material allows determination of the optimum dye material for larger-scale purification. An alternate procedure describes a similar initial selection procedure using centrifugation instead of chromatography. A support protocol describes a simple procedure for immobilization of free dyes.
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Franke I, Buck F, Hampe W. Purification of a head-activator receptor from hydra. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 244:940-5. [PMID: 9108269 DOI: 10.1111/j.1432-1033.1997.00940.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Head activator (HA) is a neuropeptide conserved from hydra to humans. It acts in the development of neuronal cells and is, in hydra, an important factor in head regeneration. Here we report the solubilization and purification of one head activator receptor (Kd approximately 1 nM) from a multiheaded mutant of Chlorohydra viridissima using HA affinity chromatography. Functional solubilization of the HA receptor from hydra membranes was best performed with Triton X-100 or Chaps. The addition of salt or urea and the protein concentration were important parameters in determining the yield of solubilized receptor. For affinity chromatography HA was coupled to Sepharose. The length of the spacer was optimized with respect to binding of the solubilized HA receptor. After rigorous washing a 200-kDa protein was eluted from HA Sepharose but not from control Sepharoses coupled to bradykinin or without peptide. Ligand binding was preserved in the eluate from the HA Sepharose, and a 200-kDa protein could be photoaffinity labeled. The 200-kDa protein was shown to be glycosylated mainly of the N-linked type. By Edman degradation of the purified protein sequence information was obtained for the N-terminus and after protease digestion for several internal peptides.
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Affiliation(s)
- I Franke
- Zentrum für Molekulare Neurobiologie, Universität Hamburg, Germany
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Abstract
Small ions of high charge density (kosmotropes) bind water molecules strongly, whereas large monovalent ions of low charge density (chaotropes) bind water molecules weakly relative to the strength of water-water interactions in bulk solution. The standard heat of solution of a crystalline alkali halide is shown here to be negative (exothermic) only when one ion is a kosmotrope and the ion of opposite charge is a chaotrope; this standard heat of solution is known to become proportionally more positive as the difference between the absolute heats of hydration of the corresponding gaseous anion and cation decreases. This suggests that inner sphere ion pairs are preferentially formed between oppositely charged ions with matching absolute enthalpies of hydration, and that biological organization arises from the noncovalent association of moieties with matching absolute free energies of solution, except where free energy is expended to keep them apart. The major intracellular anions (phosphates and carboxylates) are kosmotropes, whereas the major intracellular monovalent cations (K+; arg, his, and lys side chains) are chaotropes; together they form highly soluble, solvent-separated ion pairs that keep the contents of the cell in solution.
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Affiliation(s)
- K D Collins
- Department of Biochemistry and Molecular Biology, University of Maryland Medical School, Baltimore 21201-1503, USA.
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Abstract
Aqueous gel sieving chromatography on Sephadex G-10 of the Group IA cations (Li+, Na+, K+, Rb+, Cs+) plus NH4+ as the Cl- salts, in combination with previous results for the halide anions (F-, Cl-, Br-, I-) as the Na+ salts [Washabaugh, M.W. & Collins, K.D. (1986) J. Biol. Chem. 261, 12477-12485], leads to the following conclusions. (i) The small monovalent ions (Li+, Na+, F-) flow through the gel with water molecules attached, whereas the large monovalent ions (K+, Rb+, Cs+, Cl-, Br-, I-) adsorb to the nonpolar surface of the gel, a process requiring partial dehydration of the ion and implying that these ions bind the immediately adjacent water molecules weakly. (ii) The transition from strong to weak hydration occurs at a radius of about 1.78 A for the monovalent anions, compared with a radius of about 1.06 A for the monovalent cations (using ionic radii), indicating that the anions are more strongly hydrated than the cations for a given charge density. (iii) The anions show larger deviations from ideal behavior (an elution position corresponding to the anhydrous molecular weight) than do the cations and dominate the chromatographic behavior of the neutral salts. These results are interpreted to mean that weakly hydrated ions (chaotropes) are "pushed" onto weakly hydrated surfaces by strong water-water interactions and that the transition from strong ionic hydration to weak ionic hydration occurs where the strength of ion-water interactions approximately equals the strength of water-water interactions in bulk solution.
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Affiliation(s)
- K D Collins
- Department of Biological Chemistry, University of Maryland Medical School, Baltimore 21201-1503, USA
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Abstract
Starting from known properties of non-specific salt effects on the surface tension at an air-water interface, we propose the first general, detailed qualitative molecular mechanism for the origins of ion-specific (Hofmeister) effects on the surface potential difference at an air-water interface; this mechanism suggests a simple model for the behaviour of water at all interfaces (including water-solute interfaces), regardless of whether the non-aqueous component is neutral or charged, polar or non-polar. Specifically, water near an isolated interface is conceptually divided into three layers, each layer being I water-molecule thick. We propose that the solute determines the behaviour of the adjacent first interfacial water layer (I1); that the bulk solution determines the behaviour of the third interfacial water layer (I3), and that both I1 and I3 compete for hydrogen-bonding interactions with the intervening water layer (I2), which can be thought of as a transition layer. The model requires that a polar kosmotrope (polar water-structure maker) interact with I1 more strongly than would bulk water in its place; that a chaotrope (water-structure breaker) interact with I1 somewhat less strongly than would bulk water in its place; and that a non-polar kosmotrope (non-polar water-structure maker) interact with I1 much less strongly than would bulk water in its place. We introduce two simple new postulates to describe the behaviour of I1 water molecules in aqueous solution. The first, the 'relative competition' postulate, states that an I1 water molecule, in maximizing its free energy (--delta G), will favour those of its highly directional polar (hydrogen-bonding) interactions with its immediate neighbours for which the maximum pairwise enthalpy of interaction (--delta H) is greatest; that is, it will favour the strongest interactions. We describe such behaviour as 'compliant', since an I1 water molecule will continually adjust its position to maximize these strong interactions. Its behaviour towards its remaining immediate neighbours, with whom it interacts relatively weakly (but still favourably), we describe as 'recalcitrant', since it will be unable to adjust its position to maximize simultaneously these interactions.(ABSTRACT TRUNCATED AT 400 WORDS)
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Subramanian S. Dye-ligand affinity chromatography: the interaction of Cibacron Blue F3GA with proteins and enzymes. CRC CRITICAL REVIEWS IN BIOCHEMISTRY 1984; 16:169-205. [PMID: 6203683 DOI: 10.3109/10409238409102302] [Citation(s) in RCA: 115] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The dye Cibacron Blue F3GA has a high affinity for many proteins and enzymes. It has therefore been attached to various solid supports such as Sephadex, Sepharose, polyacrylamide, and the like. In the immobilized form the dye has rapidly been exploited as an affinity chromatographic medium to separate and purify a variety of proteins including dehydrogenases, kinases, serum albumin, interferons, several plasma proteins, and a host of other proteins. Such a diversity shown by the blue dye in binding several unrelated classes of proteins has generated considerable work in terms of studies of the chromophore itself and also the immobilized ligand. As a prelude to realizing the full potential of the immobilized Cibacron Blue F3GA, an understanding of the basic interactions of the dye with its surroundings must be gained. It has been recognized that the dye is capable of hydrophobic and/or electrostatic interactions at the instance of the ambient conditions. The study of interactions of the dye with salts, solvents, and other small molecules indicates the nature of the interactions of the dye with different kinds of groups at the interacting sites of proteins. The review will cover such interactions of the dye with the proteins, the interactions of the proteins with the immobilized ligand, and the media used to elute the bound protein in several cases, and thus consolidate the available information on such studies into a cogent and comprehensive explanation.
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Abstract
Many standard procedures for the purification of proteins in the laboratory do not readily lend themselves to scaling up, whereas, on the other hand, some techniques relatively unsatisfactory in the laboratory are much more effective on a large scale. When producing gram or kilogram quantities of enzymes for use over an extended period, the storage properties and general tractability of the purified products become increasingly important. Hence enzymes from thermophilic sources frequently have advantages over those from mesophiles. The possible economic advantages of simultaneous large-scale multi-enzyme isolation over separate individual enzyme purifications are evaluated. Batchwise adsorption and elution from ion-exchange celluloses frequently replace traditional precipitation techniques in the early stages of a large-scale purification. Dialysis is replaced by concentration, dilution and reconcentration with the use of hollow-fibre ultrafiltration equipment. Antiphonally direct scaling-up of column chromatographic procedures is usually possible. Modifications to column geometry to maximize flow rates are often desirable but purification factors and recoveries comparable with those obtained on the laboratory scale can be achieved relatively easily. Classical affinity chromatographic techniques have not proved so amenable to large-scale work, mainly because of the enormous expense and rather short life of the matrices. However, the quasi-affinity chromatography afforded by the triazine dye conjugates has proved of great benefit. The materials are cheap to prepare. The coupling procedures are both simple and rapid and do not involve the use of noxious chemicals such as cyanogen bromide. Moreover the triazine linkage is more stable under a variety of conditions than the isourea formed in cyanogen bromide coupling. Considerable further exploitation of these versatile matrices is expected.
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Andersen TT, Reichert LE. Follitropin binding to receptors in testis. Modulation by monovalent salts and divalent cations. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)33797-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Tucker R, Babul J, Stellwagen E. Protein dye affinity chromatography using immobilized tetraiodofluorescein. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)68545-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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