Ultrafast time-resolved laser-spectroscopic characterization of flavins in blue-light photo-receptors

黄素单核苷酸(FMN)和含有蓝光敏感光感受器的黄素腺嘌呤二核苷酸(FAD)将由该联盟的生物学家(P.Hegemann，A.Batschauer，W.Gärtner，E.Wolf)表达。我们想要在飞秒到纳秒的时间尺度上研究光感受器区域中发色团的超快光物理和光化学动力学。除了时间分辨荧光研究(荧光上转换、荧光放大)和泵浦-探测吸收动力学研究(单态和三态激发态吸收动力学、光异构化、光致能量转移和电子转移)外，还将进行稳态荧光光谱表征(定量荧光量子分布、绝对荧光量子产率、荧光偏振度)、荧光激发光谱表征(揭示样品组成和弛豫通道)和吸收光谱表征。实验结果将尝试用理论模型来模拟，以了解受体从激发到反应再到反向转移的光周期的早期动力学。

Flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) containing blue-light sensitive photoreceptors (LOV domains, cryptochromes, BLUF domains) will be expressed by biologists of the consortium (P. Hegemann, A. Batschauer, W. Gärtner, E. Wolf). We want to study the ultrafast photo-physical and photo-chemical dynamics of the chromophores in the photoreceptor domains on a femtosecond to nanosecond timescale. Besides time-resolved fluorescence studies (fluorescence up-conversion, fluorescence amplification) and pump-probe absorption dynamics studies (singlet excited state and triplet excitedstate absorption dynamics, photo-isomerisation, photo-induced energy transfer and electron-transfer) there will be undertaken a steady-state fluorescence spectroscopic characterisation (quantitative fluorescence quantum distribution, absolute fluorescence quantum yields, degree of fluorescence of polarisation), fluorescence excitation spectroscopic characterisation (revealing of sample composition and relaxation channels), and absorption spectroscopic characterisation. The experimental results will be tried to simulate with theoretical models to get an understanding of the early dynamics in the photo-cycle of the receptors from excitation to reaction to back-transfer.