Molar mass and temperature dependence of the thermodiffusion of polyethylene oxide in water/ethanol mixtures

Wang, Zilin; Afanasenkau, Dzmitry; Dong, Ming; Huang, Danni; Wiegand, Simone

doi:10.1063/1.4891720

Cited by 10 publications

(18 citation statements)

References 43 publications

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“…The thermal process is 3-4 orders of magnitude faster than the diffusive motion of the solute, so that the two processes can be separated. Ternary mixtures consisting of a high molar mass solute at low concentration in a solvent mixture can also be analyzed by TDFRS [22,36]. In such a ternary mixture, the concentration signal contains a fast and a slow mode resulting from the solvent molecules and the slower diffusing solute.…”

Section: Thermal Diffusion Forced Rayleigh Scatteringmentioning

confidence: 99%

Thermophoresis: The Case of Streptavidin and Biotin

et al. 2020

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Thermophoretic behavior of a free protein changes upon ligand binding and gives access to information on the binding constants. The Soret effect has also been proven to be a promising tool to gain information on the hydration layer, as the temperature dependence of the thermodiffusion behavior is sensitive to solute–solvent interactions. In this work, we perform systematic thermophoretic measurements of the protein streptavidin (STV) and of the complex STV with biotin (B) using thermal diffusion forced Rayleigh scattering (TDFRS). Our experiments show that the temperature sensitivity of the Soret coefficient is reduced for the complex compared to the free protein. We discuss our data in comparison with recent quasi-elastic neutron scattering (QENS) measurements. As the QENS measurement has been performed in heavy water, we perform additional measurements in water/heavy water mixtures. Finally, we also elucidate the challenges arising from the quantiative thermophoretic study of complex multicomponent systems such as protein solutions.

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Section: Thermal Diffusion Forced Rayleigh Scatteringmentioning

confidence: 99%

Thermophoresis: The Case of Streptavidin and Biotin

et al. 2020

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“…Despite the current lack of an overarching theory of thermophoresis of different systems, interesting trends have been observed in a variety of systems. For nonionic polymers a saturation of the thermal diffusion coefficient after several Kuhn segments has been found in a large set of nonpolar solvents 23 as well as in water 20 24 . Nevertheless, no general tendency of increasing or decreasing Soret coefficient with size for uncharged polymers has been observed 20 25 and theoretical models are still under debate 26 27 .…”

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confidence: 99%

“…The increasing recognition of the potential importance of thermophoresis for the characterization of biomolecular binding equilibria is paralleled by extensive fundamental research activity on the thermophoretic properties of polymeric and colloidal systems 16 19 20 21 , as well as solvent mixtures 22 . Despite the current lack of an overarching theory of thermophoresis of different systems, interesting trends have been observed in a variety of systems.…”

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confidence: 99%

Quantitative thermophoretic study of disease-related protein aggregates

Wolff

Mittag

Herling

et al. 2016

Sci Rep

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Amyloid fibrils are a hallmark of a range of neurodegenerative disorders, including Alzheimer’s and Parkinson’s diseases. A detailed understanding of the physico-chemical properties of the different aggregated forms of proteins, and of their interactions with other compounds of diagnostic or therapeutic interest, is crucial for devising effective strategies against such diseases. Protein aggregates are situated at the boundary between soluble and insoluble structures, and are challenging to study because classical biophysical techniques, such as scattering, spectroscopic and calorimetric methods, are not well adapted for their study. Here we present a detailed characterization of the thermophoretic behavior of different forms of the protein α-synuclein, whose aggregation is associated with Parkinson’s disease. Thermophoresis is the directed net diffusional flux of molecules and colloidal particles in a temperature gradient. Because of their low volume requirements and rapidity, analytical methods based on this effect have considerable potential for high throughput screening for drug discovery. In this paper we rationalize and describe in quantitative terms the thermophoretic behavior of monomeric, oligomeric and fibrillar forms of α-synuclein. Furthermore, we demonstrate that microscale thermophoresis (MST) is a valuable method for screening for ligands and binding partners of even such highly challenging samples as supramolecular protein aggregates.

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“…The non-ionic contribution S T NI of the Soret coefficient S T (see Eq. 12 ) scales linearly with the polymer length, as a result of local, molecule-solvent interaction around the tube-like polymer 32 , 34 , 35 . In the case of longer peptides, the contribution of the Soret coefficient which depends on the protonated state S T CM becomes comparatively smaller.…”

Section: Resultsmentioning

confidence: 99%

Proton gradients and pH oscillations emerge from heat flow at the microscale

et al. 2017

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Proton gradients are essential for biological systems. They not only drive the synthesis of ATP, but initiate molecule degradation and recycling inside lysosomes. However, the high mobility and permeability of protons through membranes make pH gradients very hard to sustain in vitro. Here we report that heat flow across a water-filled chamber forms and sustains stable pH gradients. Charged molecules accumulate by convection and thermophoresis better than uncharged species. In a dissociation reaction, this imbalances the reaction equilibrium and creates a difference in pH. In solutions of amino acids, phosphate, or nucleotides, we achieve pH differences of up to 2 pH units. The same mechanism cycles biomolecules by convection in the created proton gradient. This implements a feedback between biomolecules and a cyclic variation of the pH. The finding provides a mechanism to create a self-sustained proton gradient to drive biochemical reactions.

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Molar mass and temperature dependence of the thermodiffusion of polyethylene oxide in water/ethanol mixtures

Cited by 10 publications

References 43 publications

Thermophoresis: The Case of Streptavidin and Biotin

Thermophoresis: The Case of Streptavidin and Biotin

Quantitative thermophoretic study of disease-related protein aggregates

Proton gradients and pH oscillations emerge from heat flow at the microscale

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