Electrostatic control of photoisomerization pathways in proteins
Electrostatic control of photoisomerization pathways in proteins
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DOI：
10.1126/science.aax1898
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发表时间：
2020-01-03
期刊：
影响因子：
56.9
通讯作者：
Boxer, Steven G.
中科院分区：
文献类型：
--
作者：
Romei, Matthew G.;Lin, Chi-Yun;Boxer, Steven G.
光激发后围绕特定键的旋转是光遗传学、超分辨率显微镜和光敏分子器件中视觉和新兴机会的核心。空间和静电效应的竞争作用，支配键特异性光异构化已被广泛讨论，后者源于激发时的发色团电荷转移。我们系统地改变了光开关变体Dronpa 2中的绿色荧光蛋白发色团的静电性质，使用琥珀抑制将供电子和吸电子基团引入酚盐环。通过分析的吸收（颜色），荧光量子产率，和能量障碍的基态和激发态异构化，我们定量评估的空间和静电的贡献，并演示静电效应如何偏置的生色团光异构化的途径，导致一个广义的框架，以指导蛋白质的设计。
Rotation around a specific bond after photoexcitation is central to vision and emerging opportunities in optogenetics, super-resolution microscopy, and photoactive molecular devices. Competing roles for steric and electrostatic effects that govern bond-specific photoisomerization have been widely discussed, the latter originating from chromophore charge transfer upon excitation. We systematically altered the electrostatic properties of the green fluorescent protein chromophore in a photoswitchable variant, Dronpa2, using amber suppression to introduce electron-donating and electron-withdrawing groups to the phenolate ring. Through analysis of the absorption (color), fluorescence quantum yield, and energy barriers to ground- and excited-state isomerization, we evaluate the contributions of sterics and electrostatics quantitatively and demonstrate how electrostatic effects bias the pathway of chromophore photoisomerization, leading to a generalized framework to guide protein design.