Berlin 2018 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 45: Charged Soft Matter, Polyelectrolytes and Ionic Liquids I
CPP 45.4: Vortrag
Mittwoch, 14. März 2018, 12:00–12:15, C 243
Effects of anions on the reentrant phase behavior in protein solutions induced by multivalent salts — •Michal K. Braun1, Andrea Sauter1, Simon Schoenberg1, Michael Sztucki2, Fajun Zhang1, and Frank Schreiber1 — 1Institut für Angewandte Physik, Universität Tübingen, 72076 Tübingen — 2ESRF, Grenoble, France
Interactions between ions and proteins are a highly active research field. They are important both in metabolic processes and to more generally understand protein phase behavior [1]. Model globular proteins in solution with trivalent salts exhibit a reentrant phase behavior where in the condensed regime the cation serves as a linker between two proteins [2, 3]. The nature of the condensates is tunable by the specific cations and anions that are employed. The microscopic role of the anion is not yet fully understood. However, it has now been observed that NO3− salts lead to a stronger attraction compared to Cl− salts. This result is consistently obtained by visual inspection of the sample solutions, by monitoring the protein concentration in the supernatant using UV-vis absorption spectroscopy and by extracting potential parameters from model fits to small angle x-ray scattering data. This suggests a different affinity of Cl− vs. NO3− to the protein surface. Possible microscopic reasons such as Hofmeister effects and different entropy contributions of the anions will be discussed.
Gunton et al., Protein Condensation, 2007 [2] Zhang et al., Pure Appl. Chem., 86, 191, 2014 [3] Matsarskaia et al., J. Phys. Chem. B, 120, 7731, 2016