Modeling of Biomolecular Systems Interactions, Dynamics, and Allostery: Bridging Experiments and Computations - September 10-14, 2014, Istanbul, Turkey

Modeling of Biomolecular Systems Interactions, Dynamics, and Allostery Poster Session I

17-POS Board 17 Ab-Initio Molecular Dynamics Simulation of Photoacids: Competition between Excited

State Proton and OH - Transport via a Water Wire Gül Bekcioglu , Christoph Allolio, Daniel Sebastiani. Department of Chemistry , Halle (Saale), Germany.

Biophysical processes often take place based on proton relay along a hydrogen bonded chain [1]. Such proton transfer reactions along "water wires" are difficult to observe directly inside a protein. Photosensitive acid/base systems provide a method to control and study ultrafast proton transport via infrared spectroscopy [2]. Hydroxyquinolones (HQ), are simultaneously photoacids and photobases. We elucidate excited state proton exchange mechanisms along short chains of water molecules (water wires) by means of ab-initio calculations. We exploit the specific geometry of 7- Hydroxyquinoline, a combined photoacid/-base, to establish well-defined proton donor/acceptor sites, linked by a water wire of three water molecules [3]. In addition, departing from our successful simulation of the excited state dynamics and fluorescence shift of the related N- methyl-6-quinolone [4], we also study the ground and excited state aqueous solvation of different HQs, focussing on the identification of water wires and excited state protonation dynamics. [1] H. Luecke, H.-T. Richter, J. K. Lanyi, Science 280 (1998), 1934. [2] O. F. Mohammed, D. Pines, J. Dreyer, E. Pines and E. T. J. Nibbering., Science 310 (2005), 5745. [3] G. Bekcioglu, C. Allolio, and D. Sebastiani (submitted). [4] C. Allolio, M. Sajadi, N. P. Ernsting and D. Sebastiani, Angew. Chem. Int. Ed. 52 (2013), 1813-1816.

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