Modeling blue light energy pathways in photosynthetic complexes

• Applicant: Dr. Jan Philipp Götze
• Subject Area: Biophysics ; Plant Biochemistry and Biophysics ; Bioinformatics and Theoretical Biology ; Computer-Aided Design of Materials and Simulation of Materials Behaviour from Atomic to Microscopic Scale ; Theoretical Chemistry: Electronic Structure, Dynamics, Simulation
• Term: since 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 393271229

Most plants and other autotrophic organisms employ only the red part of the optical spectrum for photosynthetic water splitting. Other photons of higher energy will be converted to red beforehand. In the last funding period, we investigated if these processes are potentially of more complex nature. Namely, we tested if mechanisms are steered in any way or if there are various pathways of energy transport. We especially focused on the energy transfer between the blue light regions of the Chlorophylls. Furthermore, we showed that our computational methods are capable to describe both the Chlorophylls as well as supporting chromophores (carotenoids), although room for improvement exists.In the next funding period, we aim to investigate the energy transfer between antennae of plants, for both blue as well as red light photons. From the expiring funding period, we have several models of involved complexes (LHCII and CP29). We can use these as well as control proteins such as PsbS to establish a dynamical network of energy transfer. We seek to employ established approaches to this problem, and then combine our findings for red and blue light. Our assumption is that red light is transferred with higher efficiency. We have found first indications for that assumption from the current project. We also seek to include the final station of energy transfer (PSII) in our project.To reach this goal, we will make use of our own developed methods as well. We devised an interface between costly (quantum chemical) and cost-efficient (force field) approaches. To continue working on this interface is a secondary goal of this project. It allows us to efficiently generate optical spectra and protein properties, without changing the employed software.Additionally, some questions from the previous funding period remain: Which are the paths of blue light in comparison to red light under different conditions? Is intramolecular relaxation faster than transfer to other chromophores? What is the role of the exclusively blue absorbing carotenoids? Are standard models of energy transfer useful (Förster transfer) or do we need to use more elaborate models? In the next funding period, we would like to investigate these questions fully or at least partially with the help of national and international collaborations. Our main contribution to this heavily controversial field will be to investigate the contribution of the protein matrix to the effects concerning the questions stated above. This way, we will be able to provide predictions that can be tested through experiment.

• DFG Programme: Research Grants