Dresden 2020 – scientific programme
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BP: Fachverband Biologische Physik
BP 2: Focus: Phase Separation in Biological Systems I (joint session BP/CPP)
BP 2.5: Talk
Monday, March 16, 2020, 10:30–10:45, SCH A251
Kinetics and dynamics of LLPS in protein solutions exhibiting a LCST phase behavior probed by XPCS — •Anastasia Ragulskaya1, Anita Girelli1, Nafisa Begam1, Hendrik Rahmann2, Fabian Westermeier3, Fajun Zhang1, Christian Gutt2, and Frank Schreiber1 — 1Universitat Tubingen, Germany — 2Universitat Siegen, Germany — 3DESY, Hamburg
Kinetics and dynamics of liquid-liquid phase separation (LLPS) are usually intimately intertwined. We investigated a model system of bovine serum albumin (BSA) with YCl3 which shows a lower critical solution temperature (LCST) phase behavior [1]. The dynamics of spinodal decomposition after a temperature jump was studied by X–ray photon correlation spectroscopy (XPCS) and the kinetics was probed simultaneously by ultra-small angle X–ray scattering (USAXS). The analysis of two-time correlation functions obtained from XPCS shows a two-mode behavior of the dynamics. The slow mode has a relaxation rate behavior similar to the kinetic one and corresponds to the transition from a density fluctuation to a coarsening stage. The relaxation time of the fast mode has a transition from an exponential growth to a monotonic increase with a modulation as a function of time, corresponding to the further growth of domains. Results are supported by Cahn-Hilliard simulations [2]. The work demonstrates the successful use of XPCS in USAXS-mode approach to study evolution of the domains during LLPS .
[1] O.Matsarskaia et. al., Phys. Chem. B, 120 (2016), 5564.
[2] D. Sappelt, J. Jäckle, Physica A , 240 (1997) , 453.