A Computational Investigation of the Equilibrium Constants for the Fluorescent and Chemiluminescent States of Coelenteramide
A Computational Investigation of the Equilibrium Constants for the Fluorescent and Chemiluminescent States of Coelenteramide
复制标题
腔肠酰胺荧光和化学发光态平衡常数的计算研究
DOI：
10.1002/cphc.201600850
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发表时间：
2017
期刊：
影响因子：
2.9
通讯作者：
Zhu Yan-Qin
中科院分区：
文献类型：
--
作者：
Min Chun-Gang;da Silva Luis Pinto;Esteves da Silva Joaquim C. G.;Yang Xi-Kun;Huang Shao-Jun;Ren Ai-Min;Zhu Yan-Qin
尽管最近在了解腔肠动物生物发光机制方面取得了进展，但关于哪种腔肠酰胺种类和/或状态是光发射器尚无共识。在本研究中，在TD ωB97XD/6‐31+G(d)理论水平上对所有可能的光发射体的几何形状和光谱进行了系统的研究，包括在真空、疏水环境和水溶液中的各种荧光和化学发光状态。为了推导出最可能的荧光和化学发光腔肠酰胺发射器的形式，计算了连接不同种类的荧光和化学发光状态的平衡常数。ωB97XD能定性地描述荧光和化学发光结构。腔肠酰胺在“暗”化学发光状态下形成，必须进化到明亮的荧光状态。此外，苯酚基团在荧光状态下的光酸性明显高于化学发光状态，这使得酚酸盐胶肠酰胺的形成，并阐明了其作为生物发光发射器的作用。
In spite of recent advances in understanding the mechanism of coelenterate bioluminescence, there is no consensus about which coelenteramide specie and/or state are the light emitter. In this study, a systematic investigation of the geometries and spectra of all possible light emitters has been performed at the TD ωB97XD/6‐31+G(d) level of theory, including various fluorescent and chemiluminescent states in vacuum, in a hydrophobic environment and in aqueous solution. To deduce the most probable form of the fluorescent and chemiluminescent coelenteramide emitter, the equilibrium constants for the fluorescent and chemiluminescent states connecting the various species have been calculated. ωB97XD gives a qualitatively good description of fluorescent and chemiluminescent structures. Coelenteramide is formed in a “dark” chemiluminescent state and must evolve to a bright fluorescent state. Moreover, the photoacidity of the phenol group is significantly higher in the fluorescent state than in the chemiluminescent state, which allows the formation of phenolate coelenteramide and clarifies its role as the bioluminescent emitter.