Quantitative thermophoretic study of disease-related protein aggregates

Abstract

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.

Thermophoresis for characterizing biomolecular interaction

“…MST and fluorescence correlation spectroscopy (FCS) techniques were used to measure binding constant where the dissociation constants that determined by MST and F K d = 236 nM and K d = 282 nM, respectively. Different applications [43][44][45][46][47][48][49][50] of MST technique in the characterization of protein-protein interactions are summarized in Table 1.…”

What Controls Thermo-osmosis? Molecular Simulations Show the Critical Role of Interfacial Hydrodynamics

“…The fundamental coupling between thermal and hydrodynamic transport in the nanometric vicinity of liquidsolid interfaces has received scanty attention until recently. Thermophoretic phenomena, referring to the influence of temperature gradients on the flux of colloidal particles, were firstly studied for numerous applications such as optothermal DNA trapping or diseaserelated protein aggregates identification [1][2][3][4][5][6][7][8], and this interest for thermophoresis fostered work on its theoretical description [9][10][11][12][13]. On the other hand, at variance with what has been done for electro-osmosis [14][15][16][17][18][19][20][21][22] and diffusio-osmosis [23][24][25][26], very limited theoretical work has been done so far on thermo-osmosis at solid-liquid interfaces.…”

Confinement effect on the dynamics of non-equilibrium concentration fluctuations far from the onset of convection

“…NET applied to liquid mixtures shows that, when subjected to a stationary temperature gradient, molecules drift along this gradient due to Soret effect until a stationary concentration gradient is established [3]. This separation is induced by different affinities of fluid molecules to 'heat' [4] and allows a very refined control of concentration profiles in the fluid while giving the ability to investigate intimate properties of fluids like molecular interactions (chemical potentials) [5][6][7], as well as biomolecular interactions [8].…”