| Abstract [eng] |
The energy of light is necessary for the life on Earth. Organisms that have used the energy of light throughout the ages of evolution have created a complex process of photosynthesis -- a process of light absorption and transformation to chemical energy. The first stages of the process of photosynthesis take place in photosystems located inside the thylakoid. However, how the light energy is efficiently harvested and transferred to reaction centres of photosystems is still under debate. The recently proposed fluctuating antenna model that takes into account the structural dynamics of light harvesting antenna has successfully resolved the remaining controversies about the non-exponential fluorescence decay kinetics in Photosystem II. This model describes the process of excitation transfer to the reaction centre with only two parameters which provide information about the system size and the coordination of light harvesting complexes. In this study we have shown that non-exponential fluorescence decay kinetics of Photosystem I can also be described by the fluctuating antenna model. With the models of Photosystems I and II at hand, we were able to analyze the dynamics of thylakoids under different acclimation conditions and to address the questions that are still open about the adaptation of photosystems. By modeling the fluorescence decays of thylakoids in the first state we provide evidence that Photosystem I remains almost unchanged, while in the second state under very strong light a few external antenna complexes of Photosystem II migrate to Photosystem I. Particularly, the analysis of the thylakoid mutants lacking the minor light harvesting complexes of Photosystem II indicated that these complexes are responsible for regulation of the external antenna size. The Photosystem II without the minor complexes becomes enormously large. Finally, we have shown that artificial neural network models can be successfully applied to a more effective search for parameters of fluctuating antenna models. |
