Regensburg 2016 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 29: Poster: Crystallization, Nucleation, Self Assembly

CPP 29.1: Poster

Dienstag, 8. März 2016, 18:15–21:00, Poster B2

Non-classical crystallization in the presence of multivalent ions — •Benedikt Sohmen, Andrea Sauter, Fajun Zhang, and Frank Schreiber — Institut für Angewandte Physik - Universität Tübingen, Tübingen, Deutschland

Progress in the understanding of non-classical crystallization pathways of proteins was reported only recently [1]. Here, we present a real-time study of non-classical crystallization of bovine β-lactoglobulin in the presence of ZnCl₂ with respect to salt concentration c_s, protein concentration c_p and temperature by optical microscopy. The investigated c_s-c_p-phase diagram can be used as a guide to control and tune the behavior of proteins in solutions. Slightly below a certain salt concentration c^* crystals grow in a classical one-step pathway from clear solution. Increasing c_s above c^*, up to a certain salt concentration, referred to as pseudo-c^**, the crystallization follows a non-classical pathway with a dense phase as intermediate state. The crystals nucleate at the interface between dense and dilute phase. With progressing crystal growth, the dense phase dissolves. Above c^**, big aggregates are formed and no crystal growth is observed. The real-time microscopy and x-ray study provides detailed insight into the characteristics of non-classical growth and elucidates the role of the intermediate state.

[1] Sauter et al. J. Am. Chem. Soc. 137,1485-1491, (2015)