Fluorescence Enhancement of Unconstrained GFP Chromophore Analogues Based on the Push–Pull Substituent Effect
作者:Meng-Shiue Tsai、Chun-Lin Ou、Chi-Jui Tsai、Yen-Chin Huang、Yuan-Chung Cheng、Shih-Sheng Sun、Jye-Shane Yang
DOI:10.1021/acs.joc.7b01260
日期:2017.8.4
Unlike the high fluorescence quantum yield of the naturally occurring green fluorescence protein (GFP, Φf ∼ 0.8), the GFP chromophore, a benzylidenedimethylimidazolinone (BDI) dye, is nearly nonfluorescent (Φf < 0.001) in common solutions at room temperature. While many efforts have been devoted into the BDI chromophore engineering for fluorescence recovery, limited success has been achieved for structurally
不同于天然存在的绿色荧光蛋白的荧光量子收率高(GFP,Φ ˚F〜0.8)时,GFP生色团,benzylidenedimethylimidazolinone(BDI)染料,几乎是无荧光(Φ ˚F在室温下的通用解决方案<0.001)。尽管已为BDI发色团工程技术投入了大量精力进行荧光回收,但对于结构不受限制的GFP发色团类似物(uGFPc),取得了有限的成功。本文中,我们报告了uGFPc的合理设计,其正己烷中的荧光量子效率达到前所未有的高0.60。这是通过结合邻-CN和间-二甲基氨基取代基的电子效应来实现的,该电子效应在很大程度上抑制了Z →E光异构化(τ扭转)反应,是uGFPc的主要非辐射衰变通道。结构设计基于以下假设:间氨基取代的BDI系统的τ扭转会导致两性离子扭曲的中间态(1 p *),并且在邻位通过吸电子的CN取代基使1 p *态不稳定。或对位会减慢τ扭转。观察到的CN位置效果符合设计