Berlin 2012 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 22: Poster: Charged Soft Matter
CPP 22.13: Poster
Mittwoch, 28. März 2012, 11:00–13:00, Poster A
Charge-Controlled Metastable Liquid-Liquid Phase Separation in Protein Solutions as a Universal Pathway Towards Crystallization — •Felix Roosen-Runge1, Fajun Zhang1, Roland Roth2, Marcell Wolf1, Maximilian W.A. Skoda3, Robert M.J. Jacobs4, and Frank Schreiber1 — 1Institut für Angewandte Physik, Universität Tübingen — 2Institut für Theoretische Physik, Universität Erlangen-Nürnberg — 3ISIS, RAL, Chilton, Didcot, UK — 4CRL, University of Oxford, UK
We demonstrate that a metastable liquid-liquid phase separation (LLPS) can be induced by multivalent metal ions in solutions of globular proteins at room temperature [1]. Importantly, the approach is applicable to proteins, which otherwise show no LLPS in the full accessible temperature range. The ion and protein partitioning in the coexisting phases is determined in solutions of human serum albumin (HSA) and YCl3. We interpret the finding on the basis of a phase diagram with three control parameters: temperature, metal-ion and protein concentration. The underlying mechanism of specific ion binding is discussed along the lines of charge inversion and reentrant condensation [2,3]. Interestingly, we find protein crystallization close to the metastable LLPS, consistent with theoretical predictions and simulations suggesting a two-step crystallization process. Thus, multivalent ions can be used to control the phase behavior of protein solutions, including metastable LLPS and protein crystallization.
[1] F. Zhang, et al., Soft Matter, submitted; [2] F. Zhang, et al., PRL (2008) 101:148101; [3] F. Zhang et al., Proteins (2010) 78(16):3450-7