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BP: Fachverband Biologische Physik

BP 36: Posters: Tissue Dynamics, Charge Effects, and Anomalous Transport

BP 36.8: Poster

Donnerstag, 25. März 2010, 17:15–20:00, Poster B2

Charge induced liquid-liquid phase separation in protein solutions — •Marcell Wolf, Zhang Fajun, and Schreiber Frank — Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany

The liquid-liquid phase separation (LLPS) in concentrated protein solutions plays an important role for protein crystallisation as well as protein-association related diseases, such as the sickle cell anemia and eye cataracts, etc. Here, we show that the LLPS in protein solutions can be induced by using a multivalent salt, using Human Serum Albumin (HSA) and Yttrium Chloride (YCl3). The phase diagram of HSA with YCl3 was determined; it shows a re-entrant phase behaviour [1], i.e. the protein solution undergoes a phase-separation upon adding salt up to a critical value c*, c**, causes the precipitate to dissolve an the system turns back to a homogeneous solution. In the condensed phase between c* and c** the solution exhibits a (L-L) phase separation. After centrifugation, a protein-poor and a protein-rich phase were obtained and the protein concentration for each phase was determined using UV-visible spectroscopy. We also discuss the effect of the LLPS conditions for protein crystallisation.

[1] F. Zhang et al., Phys. Rev. Lett. 101 (2008) 148101