Regensburg 2019 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 10: Crystallization, nucleation and self-assembly (joint session CPP/BP)
BP 10.3: Vortrag
Dienstag, 2. April 2019, 10:00–10:15, H14
Does liquid-liquid phase separation enhance protein crystallization? — •Ralph Maier1, Andrea Sauter1, Georg Zocher1, Stefano Da Vela1, Olga Matsarskaia1, Ralf Schweins3, Michael Sztucki4, Fajun Zhang1, Thilo Stehle1,2, and Frank Schreiber1 — 1Universität Tübingen, Germany — 2Vanderbilt University School of Medicine, Nashville, USA — 3ILL, Grenoble, France — 4ESRF, Grenoble, France
Solutions of the protein human serum albumin (HSA) exhibiting a reentrant phase behavior with a metastable liquid-liquid phase separation (LLPS) inside the condensed regime in the presence of trivalent salts [1] were studied, focussing on the effects of the metastable dense liquid phase on the crystallization pathways. Optical microscopy and small angle X-ray and neutron scattering were used to follow protein crystallization and to explore the role of metastable LLPS. No evidence of nucleation inside the dense liquid phase was observed. On the contrary, heterogeneous nucleation at the walls of the glass container dominates. This suggests that the existence of a metastable LLPS is not a sufficient condition for a two-step nucleation. The unstable or metastable dense liquid phases serve as a reservoir for crystal growth. Furthermore, the crystallographic analysis of the resulting crystals shows that crystals with different morphology grown under different conditions share the same structure and the metal ions create two bridging contacts within the unit cell which stabilize the unit cell. [1] Matsarskaia et al., J. Phys. Chem. B, 120, 7731 (2016)