Regensburg 2019 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 17: Poster Session I

CPP 17.16: Poster

Montag, 1. April 2019, 17:30–19:30, Poster B1

Protein condensation in the presence of lanthanide metal ions: relating local structure at the metal centres to phase behaviour — •Olga Matsarskaia¹, Sin-Yuen Chang², Felix Roosen-Runge³, Stephen Parry², Giannantonio Cibin², Fajun Zhang¹, Sven L. M. Schroeder⁴, and Frank Schreiber¹ — ¹Universität Tübingen, Germany — ²Diamond Light Source Ltd, Didcot, UK — ³Lund University, Sweden — ⁴University of Leeds, UK

Multivalent salts, e.g. YCl₃, have been shown to induce a liquid-liquid phase separation with a lower critical solution temperature (LCST-LLPS) in aqueous solutions of bovine serum albumin (BSA), providing an intriguing experimental framework for a comprehensive study of LLPS in proteins. Here, we attempt to connect the different levels of the description of LCST-LLPS from molecular-level to macroscopic. To this end, we examine the local chemical environment of the Y³⁺ cations using extended X-ray absorption fine-structure (EXAFS) spectroscopy. The EXAFS data show that the Y³⁺ coordination number (CN) decreases with increasing protein concentration and temperature due to the partial substitution of hydration water molecules around the Y³⁺ cations by protein carboxyl groups upon Y³⁺ coordination by the protein. The results of this study thus provide molecular-level evidence that hydration effects are key to LCST-LLPS in systems of BSA and multivalent salts.