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 45.3: Vortrag
Mittwoch, 14. März 2018, 11:45–12:00, C 243
The effect of weakly and strongly interacting cations on phase behaviour of protein solutions — •Olga Matsarskaia1, Felix Roosen-Runge2, Gudrun Lotze3, Johannes Möller3, Fajun Zhang1, and Frank Schreiber1 — 1Institut für Angewandte Physik, Universität Tübingen, 72076 Tübingen — 2Division of Physical Chemistry, Lund University, Lund, Sweden — 3ESRF, Grenoble, France
Multivalent cations can induce a rich phase behaviour including reentrant condensation, clustering, liquid-liquid phase separation with a lower critical solution temperature (LCST-LLPS) and crystallisation [1], [2] in aqueous protein solutions. Interestingly, these phase behaviours strongly depend on cation-specific properties. Comparing different rare-earth metals, we find a strong decrease of an LCST-related transition temperature (Ttrans) with decreasing cation radius. This result is complemented by a thermodynamic characterisation of cation-protein binding revealing a decrease in the point of zero charge for smaller cations. Finally, significant differences in cation-induced protein-protein interaction strengths are observed using small-angle x-ray scattering (SAXS). Importantly, these point towards the fact that in addition to their radius, other cation-specific effects such as polarisability and orbital occupation can play a crucial role in cation-protein interactions. Our findings thus indicate that a careful choice of a suitable multivalent salt can help tailor protein phase behaviour [3].
[1] Zhang et al. Pure & Appl. Chem. 2014, 86, 191-202; [2] Matsarskaia et al. JPCB 2016, 120, 7731-7736; [3] Matsarskaia et al. in preparation.