Wu Qi, Huang Bolong, Niehaus T A, Yang Xiaojing, Fan Jun, Zhang Rui-Qin
Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR, China.
Phys Chem Chem Phys. 2015 Apr 28;17(16):10786-94. doi: 10.1039/c4cp06073c.
Arabidopsis thaliana UV RESISTANCE LOCUS8 (UVR8) has been identified as a photoreceptor for ultraviolet-B (UV-B). Tryptophan (Trp) residues have been shown to play a critical role in the response to UV-B irradiation in UVR8. In this work, we explore the spectroscopic behaviors of Trps in different protein environments of the UVR8 structure using the time-dependent density functional tight-binding (TD-DFTB) scheme. We show that W233 exhibits the longest absorption wavelength, highlighting its potential as a terminal Trp chromophore in the UV-B harvesting antenna. Our electronic and optical property analyses using various amino acid models support the important roles of W285 and W233 in sensing UV-B light at longer absorption wavelengths (∼290 nm). We also provide evidence for the specific function of W94 in absorption at the longest wavelengths (305.8 nm in cluster II and 304.5 nm in cluster III). To these findings, we also add information about the influence of the arginine and aspartic acid residues surrounding the Trp pyramid on the particular absorption bands (280-300 nm) that are characteristic of the UV-B photoreceptor.
拟南芥紫外线抗性位点8（UVR8）已被确定为紫外线B（UV-B）的光感受器。色氨酸（Trp）残基已被证明在UVR8对UV-B照射的反应中起关键作用。在这项工作中，我们使用含时密度泛函紧束缚（TD-DFTB）方法探索了UVR8结构中不同蛋白质环境下色氨酸的光谱行为。我们表明，W233表现出最长的吸收波长，突出了其作为UV-B捕获天线中末端色氨酸发色团的潜力。我们使用各种氨基酸模型进行的电子和光学性质分析支持了W285和W233在更长吸收波长（约290 nm）下感知UV-B光方面的重要作用。我们还提供了证据证明W94在最长波长（簇II中为305.8 nm，簇III中为304.5 nm）吸收中的特定功能。对于这些发现，我们还补充了有关色氨酸金字塔周围的精氨酸和天冬氨酸残基对UV-B光感受器特有的特定吸收带（280 - 300 nm）影响的信息。
