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Uttinger MJ, Hundschell CS, Lautenbach V, Pusara S, Bäther S, Heyn TR, Keppler JK, Wenzel W, Walter J, Kozlowska M, Wagemans AM, Peukert W. Determination of specific and non-specific protein-protein interactions for beta-lactoglobulin by analytical ultracentrifugation and membrane osmometry experiments. SOFT MATTER 2022; 18:6739-6756. [PMID: 36040122 DOI: 10.1039/d2sm00908k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Protein-protein interactions are essential for the understanding of biological processes. Specific protein aggregation is an important aspect for many biological systems. In particular, electrostatic interactions play the key role for protein-protein interactions, as many amino acids have pH-dependent charge states. Moreover, protein dissociation is directly related to the solution pH, ionic strength, temperature and protein concentration. The subtle interplay between different specific and non-specific interactions is demonstrated for beta-lactoglobulin (BLG) with a focus on low salt concentrations, thus mimicking technically relevant processing conditions. BLG is a well-characterized model system, proven to attain its monomer-dimer equilibrium strongly dependent upon the pH of the solution. In this manuscript, we present a unique combination of analytical ultracentrifugation and membrane osmometry experiments, which quantifies specific and non-specific interactions, i.e. in terms of the dimer dissociation constants and the second osmotic virial coefficient, at pH 3 and 7 and sodium chloride concentrations of 10 mM and 100 mM. This provides direct insight to protein-protein interactions for a system with a concentration-dependent monomer-dimer equilibrium. Moreover, using a coarse-grained extended DLVO model in combination with molecular dynamics simulations, we quantify non-specific monomer-monomer, monomer-dimer and dimer-dimer interactions as well as the binding free energy of BLG dimerization from theoretical calculations. The experimentally determined interactions are shown to be mainly governed by electrostatic interactions and further agree with free energy calculations. Our experimental protocol aims to determine non-specific and specific interactions for a dynamically interacting system and provides an understanding of protein-protein interactions for BLG at low salt concentrations.
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Affiliation(s)
- M J Uttinger
- Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Friedrich-Alexander-Universität Erlangen-Nürnberg, Haberstraße 9a, 91058 Erlangen, Germany.
| | - C S Hundschell
- Institute of Food Technology and Food Chemistry, Department of Food Colloids, Technical University Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - V Lautenbach
- Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Friedrich-Alexander-Universität Erlangen-Nürnberg, Haberstraße 9a, 91058 Erlangen, Germany.
| | - S Pusara
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - S Bäther
- Institute of Food Technology and Food Chemistry, Department of Food Colloids, Technical University Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - T R Heyn
- Institute of Human Nutrition and Food Science, Division of Food Technology, Kiel University, 24118 Kiel, Germany
| | - J K Keppler
- Laboratory of Food Process Engineering, Wageningen University, Wageningen, The Netherlands
| | - W Wenzel
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - J Walter
- Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Friedrich-Alexander-Universität Erlangen-Nürnberg, Haberstraße 9a, 91058 Erlangen, Germany.
| | - M Kozlowska
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - A M Wagemans
- Institute of Food Technology and Food Chemistry, Department of Food Colloids, Technical University Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - W Peukert
- Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Friedrich-Alexander-Universität Erlangen-Nürnberg, Haberstraße 9a, 91058 Erlangen, Germany.
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Ong Q, Mao T, Iranpour Anaraki N, Richter Ł, Malinverni C, Xu X, Olgiati F, Silva PHJ, Murello A, Neels A, Demurtas D, Shimizu S, Stellacci F. Cryogenic electron tomography to determine thermodynamic quantities for nanoparticle dispersions. MATERIALS HORIZONS 2022; 9:303-311. [PMID: 34739025 PMCID: PMC8725794 DOI: 10.1039/d1mh01461g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 10/15/2021] [Indexed: 05/24/2023]
Abstract
Here we present a method to extract thermodynamic quantities for nanoparticle dispersions in solvents. The method is based on the study of tomograms obtained from cryogenic electron tomography (cryoET). The approach is demonstrated for gold nanoparticles (diameter < 5 nm). Tomograms are reconstructed from tilt-series 2D images. Once the three-dimensional (3D) coordinates for the centres of mass of all of the particles in the sample are determined, we calculate the pair distribution function g(r) and the potential of mean force U(r) without any assumption. Importantly, we show that further quantitative information from 3D tomograms is readily available as the spatial fluctuation in the particles' position can be efficiently determined. This in turn allows for the prompt derivation of the Kirkwood-Buff integrals with all their associated quantities such as the second virial coefficient. Finally, the structure factor and the agglomeration states of the particles are evaluated directly. These thermodynamic quantities provide key insights into the dispersion properties of the particles. The method works well both for dispersed systems containing isolated particles and for systems with varying degrees of agglomerations.
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Affiliation(s)
- Quy Ong
- Institute of Materials, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
| | - Ting Mao
- Institute of Materials, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
| | - Neda Iranpour Anaraki
- Center for X-ray Analytics, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, St. Gallen, 9014, Switzerland
- Laboratory of Particles-Biology Interactions, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, St. Gallen, 9014, Switzerland
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, Fribourg, 1700, Switzerland
| | - Łukasz Richter
- Institute of Materials, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
| | - Carla Malinverni
- Institute of Materials, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
| | - Xufeng Xu
- Institute of Materials, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
| | - Francesca Olgiati
- Institute of Materials, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
| | | | - Anna Murello
- Institute of Materials, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
| | - Antonia Neels
- Center for X-ray Analytics, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, St. Gallen, 9014, Switzerland
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, Fribourg, 1700, Switzerland
| | - Davide Demurtas
- Interdisciplinary Centre for Electron Microscopy (CIME), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Seishi Shimizu
- York Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, UK
| | - Francesco Stellacci
- Institute of Materials, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
- Bioengineering Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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Kieserling H, Giefer P, Uttinger MJ, Lautenbach V, Nguyen T, Sevenich R, Lübbert C, Rauh C, Peukert W, Fritsching U, Drusch S, Maria Wagemans A. Structure and adsorption behavior of high hydrostatic pressure-treated β-lactoglobulin. J Colloid Interface Sci 2021; 596:173-183. [PMID: 33839350 DOI: 10.1016/j.jcis.2021.03.051] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 02/24/2021] [Accepted: 03/09/2021] [Indexed: 12/18/2022]
Abstract
HYPOTHESIS High hydrostatic pressure treatment causes structural changes in interfacial-active β-lactoglobulin (β-lg). We hypothesized that the pressure-induced structural changes affect the intra- and intermolecular interactions which determine the interfacial activity of β-lg. The conducted experimental and numerical investigations could contribute to the mechanistic understanding of the adsorption behavior of proteins in food-related emulsions. EXPERIMENTS We treated β-lg in water at pH 7 with high hydrostatic pressures up to 600 MPa for 10 min at 20 °C. The secondary structure was characterized with Fourier-transform infrared spectroscopy (FTIR) and circular dichroism (CD), the surface hydrophobicity and charge with fluorescence-spectroscopy and ζ-potential, and the quaternary structure with membrane-osmometry, analytical ultracentrifugation (AUC) and mass spectrometry (MS). Experimental analyses were supported through molecular dynamic (MD) simulations. The adsorption behavior was investigated with pendant drop analysis. FINDINGS MD simulation revealed a pressure-induced molten globule state of β-lg, confirmed by an unfolding of β-sheets with FTIR, a stabilization of α-helices with CD and loss in tertiary structure induced by an increase in surface hydrophobicity. Membrane-osmometry, AUC and MS indicated the formation of non-covalently linked dimers that migrated slower through the water phase, adsorbed more quickly due to hydrophobic interactions with the oil, and lowered the interfacial tension more strongly than reference β-lg.
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Affiliation(s)
- Helena Kieserling
- Technische Universität Berlin, Department of Food Colloids, Straße des 17. Juni 135, 10623 Berlin, Germany.
| | - Patrick Giefer
- Leibniz Institute for Materials Engineering-IWT, Particles and Process Engineering, Badgasteiner Str. 3, 28359 Bremen, Germany.
| | - Maximilian J Uttinger
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Haberstrasse 9a, 91058 Erlangen, Germany.
| | - Vanessa Lautenbach
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Haberstrasse 9a, 91058 Erlangen, Germany.
| | - Thu Nguyen
- Technische Universität Berlin, Department of Food Colloids, Straße des 17. Juni 135, 10623 Berlin, Germany.
| | - Robert Sevenich
- Technische Universität Berlin, Department of Food Biotechnology and Process Engineering, Straße des 17. Juni 135, 10623 Berlin, Germany.
| | - Christian Lübbert
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Haberstrasse 9a, 91058 Erlangen, Germany.
| | - Cornelia Rauh
- Technische Universität Berlin, Department of Food Biotechnology and Process Engineering, Straße des 17. Juni 135, 10623 Berlin, Germany.
| | - Wolfgang Peukert
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Haberstrasse 9a, 91058 Erlangen, Germany.
| | - Udo Fritsching
- Leibniz Institute for Materials Engineering-IWT, Particles and Process Engineering, Badgasteiner Str. 3, 28359 Bremen, Germany; University of Bremen, Particles and Process Engineering, Bibliothekstraße 1, 28359 Bremen, Germany.
| | - Stephan Drusch
- Technische Universität Berlin, Department of Food Technology and Food Material Science, Straße des 17. Juni 135, 10623 Berlin, Germany.
| | - Anja Maria Wagemans
- Technische Universität Berlin, Department of Food Colloids, Straße des 17. Juni 135, 10623 Berlin, Germany.
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Uttinger MJ, Jung D, Dao N, Canziani H, Lübbert C, Vogel N, Peukert W, Harting J, Walter J. Probing sedimentation non-ideality of particulate systems using analytical centrifugation. SOFT MATTER 2021; 17:2803-2814. [PMID: 33554981 DOI: 10.1039/d0sm01805h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Analytical centrifugation is a versatile technique for the quantitative characterization of colloidal systems including colloidal stability. The recent developments in data acquisition and evaluation allow the accurate determination of particle size, shape anisotropy and particle density. High precision analytical centrifugation is in particular suited for the study of particle interactions and concentration-dependent sedimentation coefficients. We present a holistic approach for the quantitative determination of sedimentation non-ideality via analytical centrifugation for polydisperse, plain and amino-functionalized silica particles spanning over one order of magnitude in particle size between 100 nm and 1200 nm. These systems typically behave as neutral hard spheres as predicted by auxiliary lattice Boltzmann simulations. The extent of electrostatic interactions and their impact on sedimentation non-ideality can be quantified by the repulsion range, which is the ratio of the Debye length and the average interparticle distance. Experimental access to the repulsion range is provided through conductivity measurements. With the experimental repulsion range at hand, we estimate the effect of polydispersity on concentration-dependent sedimentation properties through a combination of lattice Boltzmann and Brownian dynamics simulations. Finally, we determine the concentration-dependent sedimentation properties of charge-stabilized, fluorescently-labeled silica particles with a nominal particle size of 30 nm and reduced interparticle distance, hence an elevated repulsion range. Overall, our results demonstrate how the influence of hard-sphere type and electrostatic interactions can be quantified when probing sedimentation non-ideality of particulate systems using analytical centrifugation even for systems exhibiting moderate sample heterogeneity and complex interactions.
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Affiliation(s)
- M J Uttinger
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany. and Interdisciplinary Center for Functional Particle Systems (FPS), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Haberstraße 9a, 91058 Erlangen, Germany
| | - D Jung
- Forschungszentrum Jülich, Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (IEK-11), Fürther Straße 248, 90429 Nürnberg, Germany
| | - N Dao
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany.
| | - H Canziani
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany. and Interdisciplinary Center for Functional Particle Systems (FPS), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Haberstraße 9a, 91058 Erlangen, Germany
| | - C Lübbert
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany. and Interdisciplinary Center for Functional Particle Systems (FPS), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Haberstraße 9a, 91058 Erlangen, Germany
| | - N Vogel
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany. and Interdisciplinary Center for Functional Particle Systems (FPS), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Haberstraße 9a, 91058 Erlangen, Germany
| | - W Peukert
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany. and Interdisciplinary Center for Functional Particle Systems (FPS), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Haberstraße 9a, 91058 Erlangen, Germany
| | - J Harting
- Forschungszentrum Jülich, Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (IEK-11), Fürther Straße 248, 90429 Nürnberg, Germany and Department of Chemical and Biological Engineering and Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Fürther Straße 248, 90429 Nürnberg, Germany
| | - J Walter
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany. and Interdisciplinary Center for Functional Particle Systems (FPS), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Haberstraße 9a, 91058 Erlangen, Germany
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Keppler JK, Heyse A, Scheidler E, Uttinger MJ, Fitzner L, Jandt U, Heyn TR, Lautenbach V, Loch JI, Lohr J, Kieserling H, Günther G, Kempf E, Grosch JH, Lewiński K, Jahn D, Lübbert C, Peukert W, Kulozik U, Drusch S, Krull R, Schwarz K, Biedendieck R. Towards recombinantly produced milk proteins: Physicochemical and emulsifying properties of engineered whey protein beta-lactoglobulin variants. Food Hydrocoll 2021. [DOI: 10.1016/j.foodhyd.2020.106132] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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