Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University , Beijing 100875, China.
Laboratoire Modélisation et Simulation Multi Echelle, Université Paris-Est , MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallee, France.
J Chem Theory Comput. 2011 Mar 8;7(3):798-803. doi: 10.1021/ct200045q. Epub 2011 Feb 16.
This is a systematic theoretical investigation on all the possible light emitters of firefly using a multireference method. Six chemical forms of oxyluciferin (OxyLH2) molecules/anions were studied by a multistate complete active space second-order perturbation (MS-CASPT2) method in vacuum and dimethyl sulfoxide. The calculated results and subsequent analysis excluded enol-OxyLH2, keto-OxyLH2, and enolate-OxyLH(-) as possible light emitters. The remaining three candidates, phenolate-enol-OxyLH(-), phenolate-keto-OxyLH(-), and OxyL(2-), were further investigated in protein by a MS-CASPT2/molecular mechanics (MM) study to explain the natural bioluminescence of firefly. By comparison of the MS-CASPT2/MM calculated results of phenolate-enol-OxyLH(-), phenolate-keto-OxyLH(-), and OxyL(2-) with the experimental observation and detailed analysis, we concluded that the direct decomposition excited-state product of firefly dioxetanone in vivo and the only light emitter of firefly in natural bioluminescence is the first singlet excited state (S1) of phenolate-keto-OxyLH(-).
这是一项使用多参考方法对萤火虫所有可能的发光体进行系统理论研究。通过多态完全活性空间二级微扰（MS-CASPT2）方法在真空和二甲基亚砜中研究了六种化学形式的氧化荧光素（OxyLH2）分子/阴离子。计算结果和随后的分析排除了烯醇-OxyLH2、酮-OxyLH2 和烯醇-OxyLH（-）作为可能的发光体。剩下的三个候选物，酚盐-烯醇-OxyLH（-）、酚盐-酮-OxyLH（-）和 OxyL（2-），通过 MS-CASPT2/分子力学（MM）研究在蛋白质中进一步研究，以解释萤火虫的自然生物发光。通过比较酚盐-烯醇-OxyLH（-）、酚盐-酮-OxyLH（-）和 OxyL（2-）的 MS-CASPT2/MM 计算结果与实验观察和详细分析，我们得出结论，萤火虫二氧杂环丁酮在体内的直接分解激发态产物和萤火虫在自然生物发光中的唯一发光体是酚盐-酮-OxyLH（-）的第一单重激发态（S1）。
