Excited-state proton transfer dynamics in LSSmOrange studied by time-resolved impulsive stimulated Raman spectroscopy
Excited-state proton transfer dynamics in LSSmOrange studied by time-resolved impulsive stimulated Raman spectroscopy
复制标题
通过时间分辨脉冲受激拉曼光谱研究 LSSmOrange 中的激发态质子转移动力学
DOI：
10.1021/acs.jpclett.1c01653
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发表时间：
2021
影响因子：
5.7
通讯作者：
T. Tahara
中科院分区：
文献类型：
--
作者：
P. Kumar;E. Fron;H. Hosoi;H. Kuramochi;S. Takeuchi;H. Mizuno;T. Tahara
LSSmOrange是一种荧光蛋白，在吸收和发射之间具有很大的能隙，这使其成为生物成像的有用工具。LSSmOrange的这一特性源于激发态质子转移（ESPT）：中性发色团主要存在于基态，而明亮的荧光是在ESPT后从阴离子激发态发射的。有趣的是，据报道，这种ESPT过程遵循双峰动力学，但其起源还没有清楚地了解。我们使用时间分辨脉冲受激拉曼光谱（TR-ISRS），提供飞秒时间分辨拉曼光谱研究LSSmOrange的ESPT。结果表明，双峰ESPT动力学源于生色团的结构异质性。基于奇异值分解（SVD）的光谱分析得到的物种相关的拉曼光谱表明顺式和反式发色团共存于基态。这两种形式被认为是光激发的，并进行ESPT并行，导致在LSSmOrange的ESPT的双峰动力学。
LSSmOrange is a fluorescent protein that exhibits a large energy gap between absorption and emission, which makes it a useful tool for multicolor bioimaging. This characteristic of LSSmOrange originates from excited-state proton transfer (ESPT): The neutral chromophore is predominantly present in the ground state while the bright fluorescence is emitted from the anionic excited state after ESPT. Interestingly, it was reported that this ESPT process follows bimodal dynamics, but its origin has not clearly been understood. We investigate ESPT of LSSmOrange using time-resolved impulsive stimulated Raman spectroscopy (TR-ISRS) that provides femtosecond time-resolved Raman spectra. The results indicate that the bimodal ESPT dynamics originates from the structural heterogeneity of the chromophore. Species-associated Raman spectra obtained by spectral analysis based on singular value decomposition (SVD) suggest thatcisandtranschromophores coexist in the ground state. It is considered that these two forms are photoexcited and undergo ESPT in parallel, resulting in the bimodal dynamics of ESPT in LSSmOrange.