A new twist in the photophysics of the GFP chromophore: a volume-conserving molecular torsion couple.
A new twist in the photophysics of the GFP chromophore: a volume-conserving molecular torsion couple.
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DOI：
10.1039/c7sc04091a
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发表时间：
2018-02-21
期刊：
影响因子：
8.4
通讯作者：
Blancafort L
中科院分区：
文献类型：
--
作者：
Conyard J;Heisler IA;Chan Y;Bulman Page PC;Meech SR;Blancafort L
对非平面GFP生色团的动力学进行了实验和理论研究。耦合扭转运动是超快衰变的原因。绿色荧光蛋白(GFP)的发色团的简单结构，一个苯酚和一个通过亚甲基桥联的咪唑酮环，支持了一系列异常多样化的激发态现象。在这里，我们从实验和理论上描述了一种新型的GFP生色团的空间密集非平面衍生物的光化学。它经历了激发态的异构化反应，并伴随着极快的激发态衰变(亚100飞秒)。衰变动力学基本上与溶剂的极性和粘度无关。用高水平的量子化学计算对激发态结构动力学进行了探讨，揭示了快速衰变是由于以环的扭曲和亚甲基的桥碳的锥化为特征的锥形交叉点所致。交叉点可以从预扭曲的Franck-Condon结构中无障碍进入，而粘度相关性的缺乏是由于环在同一方向上扭曲的事实，产生了体积守恒的衰变坐标。此外，苯基、甲基和咪唑酮基团的旋转在空间密集结构中偶联，甲基基团将一个环的旋转转换为下一个环的旋转。因此，激发态动力学可以看作是一个扭转耦合，其中吸收的光子能量导致离面取向以体积守恒的方式从一个环转换到另一个环。对一系列亚甲基染料进行类似的修饰，可能会为分子机器提供一系列新的装置，特别是扭转对。
Dynamics of a nonplanar GFP chromophore are studied experimentally and theoretically. Coupled torsional motion is responsible for the ultrafast decay. The simple structure of the chromophore of the green fluorescent protein (GFP), a phenol and an imidazolone ring linked by a methyne bridge, supports an exceptionally diverse range of excited state phenomena. Here we describe experimentally and theoretically the photochemistry of a novel sterically crowded nonplanar derivative of the GFP chromophore. It undergoes an excited state isomerization reaction accompanied by an exceptionally fast (sub 100 fs) excited state decay. The decay dynamics are essentially independent of solvent polarity and viscosity. Excited state structural dynamics are probed by high level quantum chemical calculations revealing that the fast decay is due to a conical intersection characterized by a twist of the rings and pyramidalization of the methyne bridge carbon. The intersection can be accessed without a barrier from the pre-twisted Franck–Condon structure, and the lack of viscosity dependence is due to the fact that the rings twist in the same direction, giving rise to a volume-conserving decay coordinate. Moreover, the rotation of the phenyl, methyl and imidazolone groups is coupled in the sterically crowded structure, with the methyl group translating the rotation of one ring to the next. As a consequence, the excited state dynamics can be viewed as a torsional couple, where the absorbed photon energy leads to conversion of the out-of-plane orientation from one ring to the other in a volume conserving fashion. A similar modification of the range of methyne dyes may provide a new family of devices for molecular machines, specifically torsional couples.
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影响因子：
15
作者：
Baranov, Mikhail S.;Lukyanov, Konstantin A.;Solntsev, Kyril M.
通讯作者：
Solntsev, Kyril M.
影响因子：
4.4
作者：
BAGCHI, B;FLEMING, GR;OXTOBY, DW
通讯作者：
OXTOBY, DW
影响因子：
15
作者：
Hsu, Yen-Hao;Chen, Yi-An;Chou, Pi-Tai
通讯作者：
Chou, Pi-Tai
影响因子：
5.6
作者：
Hayashi, Ikuko;Mizuno, Hideaki;Ikura, Mitsuhiko
通讯作者：
Ikura, Mitsuhiko
影响因子：
46.9
作者：
Bulina, ME;Chudakov, DM;Lukyanov, KA
通讯作者：
Lukyanov, KA