Ground state isomerization of a model green fluorescent protein chromophore
Ground state isomerization of a model green fluorescent protein chromophore
复制标题
DOI：
10.1016/s0014-5793(03)00761-0
复制
发表时间：
2003-08-14
期刊：
影响因子：
3.5
通讯作者：
Tonge, PJ
中科院分区：
文献类型：
--
作者：
He, X;Bell, AF;Tonge, PJ
研究了绿色荧光蛋白发色团4-羟基苄基-1,2-二甲基咪唑啉酮（HBDI）基态顺反异构化与质子化的关系。我们发现质子化状态对顺式和反式异构体之间的自由能差和异构化的活化能只有适度的影响。其中，HBDI阳离子、中性和阴离子形式的实验自由能差分别为3.3、8.8和9.6 kJ/mol，阳离子、中性和阴离子形式的活化能分别为48.9、54.8和54.8 kJ/mol。此外，这些活化能比基于与类似系统的比较所期望的要小得多。这些结果表明，可能存在一个亚种群的发色团，这几乎是平等地接近所有三种质子化状态，通过热异构化可能进行。(C) 2003年由Elsevier B.V.代表欧洲生化学会联合会出版。
The relationship between ground state cis-trans isomerization and protonation state is explored for a model green fluorescent protein chromophore, 4-hydroxybenzylidene-1,2-dimethylimidazolinone (HBDI). We find that the protonation state has only a modest effect on the free energy differences between cis and trans isomers and on the activation energies for isomerization. Specifically, the experimental free energy differences are 3.3, 8.8, and 9.6 kJ/mol for cationic, neutral, and anionic forms of HBDI, respectively, and the activation energies are 48.9, 54.8, and 54.8 kJ/mol for cationic, neutral, and anionic forms, respectively. Furthermore, these activation energies are much smaller than might be expected based on comparison with similar systems. These results suggest that there may be a sub-population of the chromophore, which is nearly equally accessible to all three protonation states, through which thermal isomerization may proceed. (C) 2003 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.