Direct Observation of the Protonation States in the Mutant Green Fluorescent Protein
Direct Observation of the Protonation States in the Mutant Green Fluorescent Protein
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突变绿色荧光蛋白质子化状态的直接观察
DOI：
10.1021/acs.jpclett.9b03252
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Motoyasu Adachi
中科院分区：
文献类型：
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作者：
Chie Shibazaki; Rumi Shimizu; Yuji Kagotani; Andreas Ostermann; Tobias E. Schrader; Motoyasu Adachi
中子晶体学已被用于阐明增强型绿色荧光蛋白的质子化状态，从而彻底改变了成像技术。该结构在荧光发色团中具有去质子化的羟基。此外，His148和Thr203的质子化状态，以及与发色团直接接触的临界水分子的取向，可以确定。结果表明，发色团中的去质子化羟基和His148中的氮原子ND1分别带负电和正电，形成离子对。根据它们的省略图，在临界水分子中的两个氘原子的位置似乎稍微向受体氧原子移动。这种位移意味着在蛋白质内部形成了一个有趣的静电势。我们的发现为未来的蛋白质设计策略提供了新的见解，沿着量子化学计算的发展。
Neutron crystallography has been used to elucidate the protonation states for the enhanced green fluorescent protein, which has revolutionized imaging technologies. The structure has a deprotonated hydroxyl group in the fluorescent chromophore. Also, the protonation states of His148 and Thr203, as well as the orientation of a critical water molecule in direct contact with the chromophore, could be determined. The results demonstrate that the deprotonated hydroxyl group in the chromophore and the nitrogen atom ND1 in His148 are charged negatively and positively, respectively, forming an ion pair. The position of the two deuterium atoms in the critical water molecule appears to be displaced slightly toward the acceptor oxygen atoms according to their omit maps. This displacement implies the formation of an intriguing electrostatic potential realized inside of the protein. Our findings provide new insights into future protein design strategies along with developments in quantum chemical calculations.