Regensburg 2019 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 32: Charged Soft Matter, Polyelectrolytes and Ionic Liquids I

CPP 32.5: Vortrag

Mittwoch, 3. April 2019, 10:30–10:45, H13

Phase separation kinetics in protein-salt mixtures with compositionally tuned interactions — •Olga Matsarskaia¹, Stefano Da Vela¹, Alessandro Mariani², Zhendong Fu³, Fajun Zhang¹, and Frank Schreiber¹ — ¹Universität Tübingen, Germany — ²ESRF, Grenoble, France — ³JCNS@MLZ, Garching, Germany

Liquid-liquid phase separation (LLPS) in protein systems is relevant for phenomena such as protein condensation diseases, subcellular organisation or protein crystallisation. Understanding and controlling LLPS in proteins is therefore crucial for a number of research areas. Bovine serum albumin (BSA) has been shown to have a lower critical solution temperature-LLPS (LCST-LLPS) induceable by multivalent salts. Importantly, the nature of the employed multivalent cations influences this LCST-LLPS. Here, we present a systematic ultra-small angle X-ray scattering (USAXS) investigation of the kinetics of LCST-LLPS of BSA in the presence of different ratios of HoCl₃ and LaCl₃, resulting in different effective overall attraction strengths. We monitor the characteristic length scales ξ(t,T_fin) after inducing LLPS by subjecting the respective systems to temperature jumps into their liquid-liquid coexistence regions. With increasing interprotein attraction and increasing T_fin, we observe an increasing deviation from the growth law of ξ ∼ t^1/3 and an increased trend towards arrest despite the fact that all the cations employed are nominally trivalent. We thus establish a method for fine-tuning phase transitions in our systems with several control parameters. Our findings help shed light on general aspects of protein LLPS and its tunability.