Investigation of the Dinoflagellate Bioluminescence Mechanism: Chemically Initiated Electron Exchange Luminescence or Twisted Intramolecular Charge Transfer?
Investigation of the Dinoflagellate Bioluminescence Mechanism: Chemically Initiated Electron Exchange Luminescence or Twisted Intramolecular Charge Transfer?
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DOI：
10.1002/cptc.201700060
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发表时间：
2017-09
影响因子：
5.6
通讯作者：
Phong D. Ngo;S. Mansoorabadi
中科院分区：
文献类型：
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作者：
Phong D. Ngo;S. Mansoorabadi
甲藻在世界海洋中无处不在，能够发出奇妙的亮蓝色生物发光。这种发光度是开链四吡咯、甲藻荧光素 (LH2) 被甲藻荧光素酶 (LCF) 氧化的结果。虽然许多其他生物发光系统已广为人知，但 LCF 的反应机制仍然是个谜。采用全面的密度泛函理论研究来评估采用不同激发态发光体的 LCF 催化的几种竞争机制。这些结果为涉及激发态宝石二醇（酸酯）中间体的甲藻生物发光机制提供了强有力的证据。对与发射过程相关的分子轨道的分析表明，LH2 E-异构体的催化很可能通过化学引发的电子交换发光反应进行，而Z-异构体的催化可能涉及生物学上前所未有的扭曲分子内电荷转移态的形成。
Ubiquitous in the world's oceans, dinoflagellates are capable of fantastic displays of bright blue bioluminescence. This luminosity is a consequence of the oxidation of an open-chain tetrapyrrole, dinoflagellate luciferin (LH2), by the enzyme dinoflagellate luciferase (LCF). While many other bioluminescence systems are well understood, the reaction mechanism of LCF remains enigmatic. A comprehensive density functional theory investigation was used to evaluate several competing mechanisms of LCF catalysis employing distinct excited state luminophores. The results provide strong evidence in favor of a mechanism of dinoflagellate bioluminescence involving an excited state gem-diol(ate) intermediate. Analysis of the molecular orbitals relevant to the emission process indicates that catalysis from the E-isomer of LH2 is likely to proceed via a chemically initiated electron exchange luminescence reaction, while that from the Z-isomer may involve the formation of a biologically unprecedented twisted intramolecular charge transfer state.