SurfaceScience21 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 97: Poster Session VII: Poster to Mini-Symposium: Molecular scale investigations of liquid-vapor interfaces II
O 97.1: Poster
Donnerstag, 4. März 2021, 10:30–12:30, P
Interfacial Water Ordering Is Insufficient to Explain Ice-Nucleating Protein Activity — •Max Lukas1, Ralph Schwidetzky1, Anna T. Kunert2, Ellen H.G. Backus1,3, Ulrich Pöschl2, Janine Fröhlich-Nowoisky2, Mischa Bonn1, and Konrad Meister1,4 — 1Max Planck Institute for Polymer Research, Mainz, Germany — 2Max Planck Institute for Chemistry, Mainz, Germany — 3University of Vienna, Vienna, Austria — 4University of Alaska Southeast, Juneau, United States
Bacterial ice nucleation proteins (INPs) are the known to be the most efficient ice nucleators known. Here we study the solution structure of INPs from Pseudomonas syringae and find that there is no significant conformational change upon cooling. In contrast, upon heating on temperature exceeding ~55 °C the structure changes irreversibly, accompanied by a complete loss of ice nucleation activity. Structural ordering of interfacial water as it is observed by nonlinear sum-frequency generation (SFG) spectroscopy upon cooling is similar for active and heat-inactivated protein solutions. Our results demonstrate that the INPs' outstanding ice nucleation efficiency can not sufficiently be explained with increased water ordering at low temperatures and that the intact 3D protein structure is crucial for the underlying mechanism - taken altogether pointing to the importance of supramolecular interactions.