Chemically Modulating the Photophysics of the GFP Chromophore
Chemically Modulating the Photophysics of the GFP Chromophore
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DOI：
10.1021/jp111593x
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发表时间：
2011-02-17
影响因子：
3.3
通讯作者：
Meech, Stephen R.
中科院分区：
文献类型：
--
作者：
Conyard, Jamie;Kondo, Minako;Meech, Stephen R.
人们越来越感兴趣的工程性质的荧光蛋白，通过修改的发色团结构，利用诱变与天然或非天然氨基酸。这需要了解改性发色团的光物理和光化学性质。在这项工作中，一系列的GFP发色团与不同的烷基取代基的合成和它们的电子光谱，pH依赖性，和超快荧光衰减动力学进行了研究。烷基取代基的弱供电子特性导致阴离子的电子光谱发生显著的红移，这伴随着荧光衰减时间的增加。这种电子结构对取代的高度敏感性也是某些荧光蛋白的特征。溶剂粘度依赖的衰减动力学进行了研究，并发现是一致的双峰无辐射弛豫坐标。一些取代基被证明扭曲的生色团的平面结构，这将导致在电子光谱中的蓝移和无辐射衰减的强烈增强。这些数据的合理设计的新型荧光蛋白的意义进行了讨论。
There is growing interest in engineering the properties of fluorescent proteins through modifications to the chromophore structure utilizing mutagenesis with either natural or unnatural amino acids. This entails an understanding of the photophysical and photochemical properties of the modified chromophore. In this work, a range of GFP chromophores with different alkyl substituents are synthesized and their electronic spectra, pH dependence, and ultrafast fluorescence decay kinetics are investigated. The weakly electron donating character of the alkyl substituents leads to dramatic red shifts in the electronic spectra of the anions, which are accompanied by increased fluorescence decay times. This high sensitivity of electronic structure to substitution is also characteristic of some fluorescent proteins. The solvent viscosity dependence of the decay kinetics are investigated, and found to be consistent with a bimodal radiationless relaxation coordinate. Some substituents are shown to distort the planar structure of the chromophore, which results in a blue shift in the electronic spectra and a strong enhancement of the radiationless decay. The significance of these data for the rational design of novel fluorescent proteins is discussed.