Laboratoire de Chimie, Univ Lyon, Ens de Lyon, CNRS UMR 5182, Université Claude Bernard Lyon 1, 69342, Lyon, France.
IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133, Milano, Italy.
Chemistry. 2021 Nov 25;27(66):16389-16400. doi: 10.1002/chem.202102383. Epub 2021 Oct 28.
Artificial biomimetic chromophore-protein complexes inspired by natural visual pigments can feature color tunability across the full visible spectrum. However, control of excited state dynamics of the retinal chromophore, which is of paramount importance for technological applications, is lacking due to its complex and subtle photophysics/photochemistry. Here, ultrafast transient absorption spectroscopy and quantum mechanics/molecular mechanics simulations are combined for the study of highly tunable rhodopsin mimics, as compared to retinal chromophores in solution. Conical intersections and transient fluorescent intermediates are identified with atomistic resolution, providing unambiguous assignment of their ultrafast excited state absorption features. The results point out that the electrostatic environment of the chromophore, modified by protein point mutations, affects its excited state properties allowing control of its photophysics with same power of chemical modifications of the chromophore. The complex nature of such fine control is a fundamental knowledge for the design of bio-mimetic opto-electronic and photonic devices.
受天然视觉色素启发的人工仿生生色团-蛋白质复合物可以在整个可见光谱范围内实现颜色可调性。然而，由于其复杂而微妙的光物理/光化学，对视网膜生色团的激发态动力学的控制（这对于技术应用至关重要）仍然缺乏。在这里，超快瞬态吸收光谱和量子力学/分子力学模拟相结合，用于研究高度可调的视蛋白模拟物，与溶液中的视网膜生色团相比。通过原子分辨率确定了锥形交叉和瞬态荧光中间体，明确分配了它们的超快激发态吸收特征。结果表明，通过蛋白质点突变修饰的生色团的静电环境会影响其激发态性质，从而可以通过与生色团的化学修饰相同的方式控制其光物理性质。这种精细控制的复杂性质是设计仿生光电和光子器件的基础知识。
