Berlin 2018 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 3: Complex Fluids and Colloids I (joint session CPP/DY)
DY 3.5: Vortrag
Montag, 12. März 2018, 10:30–10:45, C 264
Interactions in Protein Solutions in the Vicinity of the Gas-Liquid Binodal — •Jan Hansen1, Florian Platten1, Jannik Nedergaard Pedersen2, Jan Skov Pedersen2, and Stefan U. Egelhaaf1 — 1Condensed Matter Physics Laboratory, Heinrich Heine University, Düsseldorf, Germany — 2Department of Chemistry & iNANO, Aarhus University, Denmark
Intermolecular interactions in protein solution depend on a delicate balance of electrostatic, van der Waals and hydrophobic interactions, hydration and other specific contributions. Under certain conditions, short-ranged attractions dominate. Then, proteins can be described as adhesive hard spheres, i.e. their equilibrium phase diagram contains a solubility line below which the metastable gas-liquid binodal is submerged. Here, we examine in how far effective interaction models from colloid science can help to rationalize the phase behavior and interactions of protein solutions in the vicinity of the gas-liquid binodal. For different solution compositions, binodals have been determined by cloud-point measurements, yielding estimates of the critical temperature Tc. The effective structure factor of protein solutions has been determined for various protein concentrations and temperatures by small-angle X-ray scattering. The data is well described by a one-parameter fit based on Baxter’s model, from which the second virial coefficient B2 is inferred. If plotted as a function of temperature normalized by Tc, the values of B2 follow a universal behaviour for various solution conditions, as suggested by the extended law of corresponding states.