Molecular Understanding of the Photophysics and Photochemistry of the Cyanobacteriochrome Slr1393g3

该研究项目将在分子水平上了解光感受器蛋白Slr 1393 g3的生物物理学（例如可见光吸收）和光化学（例如发色团的异构化机制）特性。为此，将研究两种不同形式的蛋白质（反应物和产物）：一种形式吸收红光，另一种吸收绿色。这两种形式都可以通过光照相互转换。因此，他们是有前途的候选人使用的光电开关在生物技术的应用。实验确定的晶体结构将是计算研究的起点。这个研究项目得益于我以前在共轭体系和光致变色分子的光物理和光化学方面的经验，这是我博士学位的主题。它分为主要项目。第一个项目将建立一个通用的协议，用于确定的光谱，即物理，性能的两种形式采用QM/MM方法。第二部分是关于光化学性质的研究：首先确定了一种适合于计算小模型体系光诱导动力学的量子力学方法，然后将该方法应用于QM/MM模型中，模拟发色团-蛋白质复合物的动力学。此外，在激发态的反应性将预测与最小能量路径。设想的方法，结合实验和理论，将产生一个基本的理解不同的生物物理和光化学性质的两种形式的蛋白质。以这种方式获得的见解将用于专门调整静态和动态属性。在研究项目的每个阶段，我们的计算结果将与实验进行比较，以验证我们的模型或在必要时改进我们的模型。最后，在分子水平上获得的详细了解将在未来的感光蛋白的知识为基础的设计的基础。

The proposed research project will result in an understanding of the photophysical, e.g. absorption of visible light, and photochemical, e.g. isomerization mechanism of the chromophore, properties of the photoreceptor protein Slr1393g3 on the molecular level. For this purpose, two different forms of the protein (reactant and product) will be investigated: one form absorbs red light and the other one green. Both forms can be interconverted into each other by light illumination. Therefore, they are promising candidates for the use as photoswitches in biotechnological applications.Experimentally determined crystal structures will be the starting point of the computational investigations. The research project benefits of my previous experiences regarding phohtophysics and photochemistry of conjugated systems and photochromic molecules, which was the topic of my PhD. It is divided in to main projects. The first project will establish a universal protocol for the determination of the spectroscopic, i.e. photophysical, properties of both forms employing the QM/MM method. the second one is concerned with the photochemical properties: Starting with the determination of an adequate quantum mechanical method for the calculation of the light-induced dynamics for a small model system, this method will be used in an QM/MM model to simulate the dynamics of the chromophore-protein complex. In addition, the reactivity in the excited state will be predicted with minimum energy paths. The envisaged approach, which combines experiment and theory, will yield a fundamental understanding of the different photophysical and photochemical properties of both forms of the protein. The insights obtained this way will be used to specifically tune the static and dynamical properties. At every stage of the research project, our calculated results will be compared with experiment to verify our modeling or to improve our models if necessary. Finally, the obtained detailed understanding on a molecular level will be the basis for the knowledge-based design of photoreceptor proteins in the future.