Dresden 2014 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
BP: Fachverband Biologische Physik
BP 28: Protein structure and dynamics II
BP 28.8: Vortrag
Mittwoch, 2. April 2014, 17:15–17:30, HÜL 386
Structure and dynamics of interfacial water associated with the climate-active ice nucleating proteins probed by sum frequency generation spectroscopy — •Ravindra Pandey1, Janine Fröhlich2, Ulrich Pöschl2, Ruth Livingstone1, Mischa Bonn1, and Tobias Weidner1, 3 — 1Max-Planck Institute for Polymer Research, Mainz — 2Max-Planck Institute for Chemistry, Mainz — 3Chemical Engineering, University of Washington, USA
Specific Bacteria such as Pseudomonas syringae effectively attack plants by using ice-nucleating proteins (INP) anchored to their outer cell surfaces. INP promotes the growth of ice crystals. To understand the ice formation by INP, it is important to understand the molecular mechanisms by which INP interact with water molecules. In this study, we have investigated the interaction of a monolayer of the INP with water molecules at the air-water interface using static and time resolved sum frequency generation spectroscopy. When cooling the monolayer of the INP with water molecules from room temperature to near-freezing temperature, an increase in the structural order of interfacial water molecules was observed. This effect was not observed for water surface or for proteins lacking ice nucleating activity. By using femtosecond pump probe SFG spectroscopy, we found a decrease of the lifetime of the O-D stretch vibrations as a function of temperature. This may be explained by strongly bound O-D groups, which play a decisive role in the ice nucleating activity. The specific binding at lower temperatures could be due to side chain orientations, which emulate the lattice of ice and hence promote the ice formation.