Štěpánek Petr, Cowie Thomas Y, Šafařík Martin, Šebestík Jaroslav, Pohl Radek, Bouř Petr
NMR Research Group, Faculty of Science, University of Oulu, PO Box 3000, 90014, Oulu, Finland.
Institute of Organic Chemistry and Biochemistry, AS CR, Flemingovo náměstí 2, 166 10, Prague, Czech Republic.
Chemphyschem. 2016 Aug 4;17(15):2348-54. doi: 10.1002/cphc.201600313. Epub 2016 May 12.
The detailed electronic structures of fluorescent chromophores are important for their use in imaging of living cells. A series of green fluorescent protein chromophore derivatives is examined by magnetic circular dichroism (MCD) spectroscopy, which allows the resolution of more bands than plain absorption and fluorescence. Observed spectral patterns are rationalized with the aid of time-dependent density functional theory (TDDFT) computations and the sum-over-state (SOS) formalism, which also reveals a significant dependence of MCD intensities on chromophore conformation. The combination of organic and theoretical chemistry with spectroscopic techniques also appears useful in the rational design of fluorescence labels and understanding of the chromophore's properties. For example, the absorption threshold can be heavily affected by substitution on the phenyl ring but not much on the five-member ring, and methoxy groups can be used to further tune the electronic levels.
荧光发色团的详细电子结构对于其在活细胞成像中的应用至关重要。通过磁圆二色性（MCD）光谱对一系列绿色荧光蛋白发色团衍生物进行了研究，该光谱能够分辨出比普通吸收和荧光更多的谱带。借助含时密度泛函理论（TDDFT）计算和态叠加（SOS）形式对观察到的光谱模式进行了合理解释，这也揭示了MCD强度对发色团构象的显著依赖性。有机化学和理论化学与光谱技术的结合似乎也有助于荧光标记的合理设计以及对发色团性质的理解。例如，吸收阈值会受到苯环上取代基的严重影响，但五元环上的取代基对其影响不大，甲氧基可用于进一步调节电子能级。
