Regensburg 2019 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 27: Complex Fluids and Colloids, Micelles and Vesicles (joint session CPP/DY)

DY 27.3: Talk

Wednesday, April 3, 2019, 10:15–10:30, H14

Dynamics during the formation of an arrested protein phase separation studied using X-ray photon correlation spectroscopy — •Nafisa Begam¹, Anita Girelli¹, Anastasia Ragulskaya¹, Hendrik Rahmann², Kevin Lopata², Fabian Westermeier³, Christian Gutt², Fajun Zhang¹, and Frank Schreiber¹ — ¹Universität Tübingen, Germany — ²Universität Siegen, Germany — ³Petra III, DESY, Germany

Phase separation in aqueous protein solutions is of primary interest in the field of many biological and chemical processes. It is observed that the glass line often interrupts the phase separation [1] and leads the solution to a dynamically arrested state which results in a drastic reduction of the microscopic relaxation rate. Kinetics of phase separation of such a system of bovine γ-globulin in the presence of polyethylene glycol studied using ultra-small angle X-ray scattering [2] shows an arrest for a quench to temperatures below ∼ 2.5^∘C. Here, our goal is to study the dynamics of the solution while approaching such an arrested state. We have used X-ray photon correlation spectroscopy which provides the time evolution of dynamics in the form of two time correlation (TTC) functions. A systematic study of the evolving dynamics of protein solutions during arrest at different quench temperatures using TTC exhibits initially an exponential growth of the relaxation time and at the later stage, an ageing heterogeneous dynamics. This study reveals a comprehensive picture of the protein dynamics that leads the solution to an arrested state. [1] Cardinaux et. al, Phys. Rev. Lett., 99, 118301, (2007) [2] S. Da Vela et. al, Soft Matter, 13, 8756, (2017)