Theoretical Study of the Wavelength Selection for the Photocleavage of Coumarin‐caged D‐luciferin
Theoretical Study of the Wavelength Selection for the Photocleavage of Coumarin‐caged D‐luciferin
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香豆素笼D-荧光素光裂解波长选择的理论研究
DOI：
10.1111/php.13212
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发表时间：
2020
影响因子：
3.3
通讯作者：
Koga Nobuaki
中科院分区：
文献类型：
--
作者：
Usukura Junko;Hiyama Miyabi;Kurata Maki;Hazama Yuji;Qiu Xing‐Ping;Winnik Francoise M.;Akiyama Hidefumi;Koga Nobuaki
通过量子化学计算，研究了可光笼状D-荧光素(7-二乙氨基香豆素-4-基)甲基笼状D-荧光素(DEACM-Cage D-Luciferin)在水溶液中的平衡结构和光学性质。通过势能曲线扫描和结构优化确定了DEACM笼状D-荧光素的可能构象。通过比较优化结构的Gibbs自由能，我们确定了DEACM笼状D-荧光素在水中的40种可能构象。尽管它们的结构不同，但在三个低激发态的指配、振子强度和能量方面，构象是相似的。根据构象浓度和振子强度，我们得到了DEACM笼状D-荧光素的理论UV/Vis光谱，该光谱有两个主要带，其形状与实验UV/Vis光谱几乎相同。理论UV/Vis光谱分析表明，最大吸收峰为384 nm和339 nm，分别归因于笼状基团和荧光素部分的电子激发。此外，分析表明，笼化组的DEACM-Cage D-荧光素只能被波长在400-430 nm之间的光激发，该光位于384 nm波段的长波尾部。这一点应该进行测试，以降低光解理时的损害。
The equilibrium structures and optical properties of the photolabile caged luciferin, (7‐diethylaminocoumarin‐4‐yl)methyl caged D‐luciferin (DEACM‐caged D‐luciferin), in aqueous solution were investigated via quantum chemical calculations. The probable conformers of DEACM‐caged D‐luciferin were determined by potential energy curve scans and structural optimizations. We identified 40 possible conformers of DEACM‐caged D‐luciferin in water by comparing the Gibbs free energy of the optimized structures. Despite the difference in their structures, the conformers were similar in terms of assignments, oscillator strengths and energies of the three low‐lying excited states. From the concentrations of the conformers and their oscillator strengths, we obtained a theoretical UV/Vis spectrum of DEACM‐caged D‐luciferin that has two main bands of shape nearly identical to the experimental UV/Vis spectrum. The absorption bands with maxima ~ 384 and 339 nm were attributed to the electronic excitations of the caged group and the luciferin moiety, respectively, by analysis of the theoretical UV/Vis spectrum. Furthermore, the analysis showed that DEACM‐caged D‐luciferin is excited in the caged group only by light of wavelength ranging within 400–430 nm, which is in the long‐wavelength tail of the 384 nm band. This should be tested to lower damage upon photocleavage.