Dresden 2020 – scientific programme

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SYSD: Symposium SKM Dissertation Prize 2020

SYSD 1: SKM Dissertation Prize

SYSD 1.4: Invited Talk

Monday, March 16, 2020, 10:45–11:10, HSZ 02

Multivalent ions for tuning the phase behaviour of protein solutions — •Olga Matsarskaia — University of Tübingen, Germany — present address: Institut Laue-Langevin, Grenoble, France

Protein interactions can be mediated by a variety of factors such as charges introduced via ions. These interactions, in turn, determine protein phase behaviour including aggregation, phase separation and crystallisation with implications for several pathologies, biotechnology and structural biology. A detailed understanding of ion-mediated protein phase behaviour is thus crucial. Here, this subject was investigated using aqueous solutions of a globular protein in the presence of multivalent ions. The ion-induced phase behaviour was studied by a multi-method approach including calorimetry, UV-Vis absorption and small-angle scattering. In a first step, the unusual temperature dependence of the experimental system was analysed and determined to be due to hydration entropy effects. Subsequently, this entropy-driven mechanism was visualised on a molecular level by monitoring the ion-protein interactions. Finally, ion-specific effects were investigated. Intriguingly, the type of ion used was found to have a profound impact on both equilibrium phase behaviour and phase separation kinetics, in spite of all ions used featuring the same net charge. These results imply that subtle differences in ion properties are important factors capable of tuning protein interactions. The findings presented thus help advance an in-depth understanding of charge-mediated protein thermodynamics.