Evidence for a vibrational phase-dependent isotope effect on the photochemistry of vision
Evidence for a vibrational phase-dependent isotope effect on the photochemistry of vision
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DOI：
10.1038/s41557-018-0014-y
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发表时间：
2018-04-01
期刊：
影响因子：
21.8
通讯作者：
Mathies, R. A.
中科院分区：
文献类型：
--
作者：
Schnedermann, C.;Yang, X.;Mathies, R. A.
振动耦合是分子系统中有效能量流动的关键，也是生物过程中大多数量子效应机制的关键组成部分。尽管越来越多的证据表明电子态的相干耦合是由振动运动介导的，但尚不清楚与振动相干性相关的性质（如原子运动的相位和耦合）如何以及在多大程度上影响自然非相干照明下光诱导过程的效率。本研究表明，视色素视紫红质中11-顺式视网膜发色团的H-11-C-11=C-12-H-12双键的氘化作用显著且意外地改变了光异构化产率，同时引起了已知同位素效应下超快异构化动力学的较小变化。这些结果与非绝热分子动力学模拟相结合，揭示了振动相依赖的同位素效应，我们认为这是振动相干光化学过程的固有属性。
Vibronic coupling is key to efficient energy flow in molecular systems and a critical component of most mechanisms invoking quantum effects in biological processes. Despite increasing evidence for coherent coupling of electronic states being mediated by vibrational motion, it is not clear how and to what degree properties associated with vibrational coherence such as phase and coupling of atomic motion can impact the efficiency of light-induced processes under natural, incoherent illumination. Here, we show that deuteration of the H-11-C-11=C-12-H-12 double-bond of the 11-cis retinal chromophore in the visual pigment rhodopsin significantly and unexpectedly alters the photoisomerization yield while inducing smaller changes in the ultrafast isomerization dynamics assignable to known isotope effects. Combination of these results with non-adiabatic molecular dynamics simulations reveals a vibrational phase-dependent isotope effect that we suggest is an intrinsic attribute of vibronically coherent photochemical processes.