期刊
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
卷 125, 期 23, 页码 6962-6971出版社
AMER CHEMICAL SOC
DOI: 10.1021/ja021255a
关键词
-
Reaction mechanisms for the formation of the keto-form of oxyluciferin (OxyLH(2)) from the luciferin of fireflies via a dioxetanone intermediate are predicted using the B3LYP/6-31G* theoretical method. The ring opening of a model dioxetanone and the decarboxylation proceed in one step via a singlet diradical transition structure with an activation barrier of 18.1 and an exothermicity of 90.8 kcal/mol. The S-0 --> S-1 vertical excitation energies predicted with time dependent density functional theory, TDDFT B3LYP/6-31+G*, for the anionic and neutral forms of OxyLH(2) are in the range of 60 to 80 kcal/mol. These energetic results support the generally accepted theory of chemically initiated electron exchange luminescence (CIEEL). The chemical origin of the multicolor bioluminescence from OxyLH(2) is examined theoretically using the TDDFT B3LYP/6-31+G*, ZINDO//B3LYP/6-31+G*, and CIS/6-31G* methods. A change in color of the light emission upon rotation of the two rings in the S-1 excited state of OxyLH(2) is unlikely because both possible emitters, the planar keto- and enol-forms, are minima on the S-1 potential energy surface. The participation of the enol-forms of OxyLH(2) in bioluminescence is plausible but not required to explain the multicolor emission. According to predictions at the TDDFT B3LYP level, the color of the bioluminescence depends on the polarization of the OxyLH(2) in the microenvironment of the enzyme-OxyLH(2) complex.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据