Center for Quantum Technology Research, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China.
Beijing Academy of Quantum Information Sciences, Beijing 100193, China.
Phys Chem Chem Phys. 2024 Oct 17;26(40):26004-26011. doi: 10.1039/d4cp02970d.
To gain insights into the light-harvesting capabilities of the chromophores, it is essential to understand their molecular and electronic structures within their natural chemical or biological contexts. Rhodopsins display varied absorption characteristics due to the interaction between the chromophore retinal and its surrounding protein environments. In this study, we employed a quantum mechanics/molecular mechanics approach to examine a series of artificially designed rhodopsin mimics based on human cellular retinol acid binding protein 2 (hCRABP II). We elucidated the electron transfer within the all- protonated Schiff base upon light excitation, and our calculated absorption spectra show well consistency with the experimental result. Furthermore, the interaction mechanisms between the chromophore and the protein were investigated, and the relationship between the blueshifts and redshifts in the absorption spectra was analyzed. Our calculation demonstrates that the blueshifts and redshifts in the rhodopsin mimics correlate well with attractive (such as the hydrogen bonds or electrostatic interactions) and repulsive interactions (such as the steric effects) between the chromophore and the protein environment, respectively. These findings could provide hints for designing rhodopsin with absorption spectra at different wavelengths.
为了深入了解发色团的光捕获能力，了解它们在自然化学或生物环境中的分子和电子结构至关重要。视蛋白因发色团视黄醛与其周围蛋白质环境的相互作用而表现出不同的吸收特性。在这项研究中，我们采用量子力学/分子力学方法研究了一系列基于人细胞视黄醇结合蛋白 2 (hCRABP II) 的人工设计的视蛋白模拟物。我们阐明了光激发下全质子化席夫碱内的电子转移，并且我们计算的吸收光谱与实验结果具有很好的一致性。此外，我们还研究了发色团和蛋白质之间的相互作用机制，并分析了吸收光谱中蓝移和红移的关系。我们的计算表明，视蛋白模拟物中的蓝移和红移与发色团和蛋白质环境之间的吸引力相互作用（如氢键或静电相互作用）和排斥力相互作用（如空间位阻效应）分别相关。这些发现可为设计具有不同波长吸收光谱的视蛋白提供启示。
