Novel Non-Linear Spectroscopic Probes of the Primary Photoreactions of Photolyases and Cryptochromes

• Applicant: Professor Dr. Benjamin Fingerhut
• Subject Area: Theoretical Chemistry: Molecules, Materials, Surfaces ; Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: from 2014 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 260966011

The aim of this project is the development of novel simulation algorithms for state-of-the-art time resolved vibrational and optical spectroscopic techniques. Both techniques exploit different windows of observation to provide a real time view of ultrafast, conical intersection mediated photoreactions. The involved molecular motions can be directly observed by time- and frequency-resolved infrared or Raman techniques. For their simulation a hierarchy of algorithms will be developed which cover full quantum simulation protocols as benchmark for introduced semiclassical approximations to facilitate simulations of characteristic vibronic signatures of biological relevant systems. Multidimensional optical spectroscopic techniques monitor energy fluxes and interactions between chromophores. Novel simulation protocols based on a co-bosonization of fermionic multi-excitons will allow to predict innovative higher order signals which reveal many-body correlations in chromophore aggregates and make transport phenomena in the important UV spectral region accessible. The algorithmic developments will be used to uncover the mechanism of the complex primary photoreactions in the Photolyase/Cryptochrome flavoprotein superfamily. Time-resolved vibrational techniques will allow to predict real-time molecular probes of the photolesion reversion to resolve controversial mechanistic predictions of (6-4) photoproduct repair. Predicted multidimensional optical signals will be used to discriminate between the charge transfer pathways in Cryptochromes to develop a universal model of the primary steps of signal transduction. Novel multidimensional chirality induced signals have the potential to follow conformational changes upon light absorption in real time in order to provide a detailed picture of the conversion of electronic excitation into the mechanical motion required for signal transduction. The theoretical developments of the project have thus the potential to uncover spectroscopic signatures of the earliest mechanistic steps of biological important processes by relating the known protein structure to the light induced dynamics to provide a comprehensive picture of the protein function.

• DFG Programme: Independent Junior Research Groups