Reinot Tonu, Khmelnitskiy Anton, Kell Adam, Jassas Mahboobe, Jankowiak Ryszard
Department of Chemistry, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States.
ACS Omega. 2021 Feb 19;6(8):5990-6008. doi: 10.1021/acsomega.1c00286. eCollection 2021 Mar 2.
Significant protein rearrangement upon excitation and energy transfer in Fenna-Matthews-Olson protein of results in a modified energy landscape, which induces more changes in pigment site energies than predicted by the "standard" hole-burning theory. The energy changes are elucidated by simulations while investigating the effects of site-dependent disorder, both static (site-energy distribution widths) and dynamic (spectral density shapes). The resulting optimized site energies and their fluctuations are consistent with relative differences observed in inhomogeneous widths calculated by recent molecular dynamic simulations. Two sets of different spectral densities reveal how their shapes affect the population dynamics and distribution of exciton lifetimes. Calculations revealed the wavelength-dependent distributions of exciton lifetimes ( ) in the femtosecond to picosecond time frame. We suggest that the calculated multimodal and asymmetric wavelength-dependent distributions offer more insight into the interpretation of resonant hole-burned (HB) spectra, kinetic traces in two-dimensional (2D) electronic spectroscopy experiments, and widely used global analyses in fitting data from transient absorption experiments.
在芬纳 - 马修斯 - 奥尔森蛋白中，激发和能量转移时显著的蛋白质重排导致能量景观发生改变，这引起的色素位点能量变化比“标准”空穴烧蚀理论预测的更多。在研究静态（位点能量分布宽度）和动态（光谱密度形状）的位点依赖性无序效应时，通过模拟阐明了能量变化。由此得到的优化位点能量及其波动与最近分子动力学模拟计算出的非均匀宽度中观察到的相对差异一致。两组不同的光谱密度揭示了它们的形状如何影响激子寿命的布居动力学和分布。计算揭示了飞秒到皮秒时间范围内激子寿命（ ）的波长依赖性分布。我们认为，计算出的多峰和不对称波长依赖性 分布为解释共振空穴烧蚀（HB）光谱、二维（2D）电子光谱实验中的动力学轨迹以及拟合瞬态吸收实验数据时广泛使用的全局分析提供了更多见解。
