Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C (Denmark); Chemistry Department, M.V. Lomonosov Moscow State University, 119991 Moscow (Russia).
Angew Chem Int Ed Engl. 2014 Sep 8;53(37):9797-801. doi: 10.1002/anie.201404609. Epub 2014 Jul 15.
Members of the green fluorescent protein (GFP) family may undergo irreversible phototransformation upon irradiation with UV light. This provides clear evidence for the importance of the higher-energy photophysics of the chromophore, which remains essentially unexplored. By using time-resolved action and photoelectron spectroscopy together with high-level electronic structure theory, we directly probe and identify higher electronically excited singlet states of the isolated para- and meta-chromophore anions of GFP. These molecular resonances are found to serve as a doorway for very efficient electron detachment in the gas phase. Inside the protein, this band is found to be resonant with the quasicontinuum of a solvated electron, thus enhancing electron transfer from the GFP to the solvent. This suggests a photophysical pathway for photoconversion of the protein, where GFP resonant photooxidation in solution triggers radical redox reactions inside these proteins.
绿色荧光蛋白（GFP）家族的成员在受到紫外线照射时可能会发生不可逆的光转化。这为发色团的高能光物理特性提供了明确的证据，而这一特性在很大程度上尚未得到探索。通过使用时间分辨的光电子和光电子能谱以及高精度的电子结构理论，我们直接探测并识别了 GFP 中分离的对映和间位发色团阴离子的更高电子激发单重态。这些分子共振被发现是气相中非常高效的电子脱离的门户。在蛋白质内部，该带与溶剂化电子的准连续谱共振，从而增强了 GFP 向溶剂的电子转移。这表明了蛋白质光转化的光物理途径，其中 GFP 在溶液中的共振光氧化触发了这些蛋白质内部的自由基氧化还原反应。
