Dreuw Andreas, Wormit Michael
Institut für Physikalische und Theoretische Chemie, Johann Wolfgang Goethe-Universität, Max von Laue-Str. 7, 60438 Frankfurt a. Main, Germany.
J Inorg Biochem. 2008 Mar;102(3):458-65. doi: 10.1016/j.jinorgbio.2007.09.013. Epub 2007 Nov 28.
Recently, a mechanism for the energy-dependent component (qE) of non-photochemical quenching (NPQ), the fundamental photo-protection mechanism in green plants, has been suggested. Replacement of violaxanthin by zeaxanthin in the binding pocket of the major light harvesting complex LHC-II may be sufficient to invoke efficient chlorophyll fluorescence quenching. Our quantum chemical calculations, however, show that the excited state energies of violaxanthin and zeaxanthin are practically identical when their geometry is constrained to the naturally observed structure of violaxanthin in LHC-II. Therefore, since violaxanthin does not quench LHC-II, zeaxanthin should not either. This theoretical finding is nicely in agreement with experimental results obtained by femtosecond spectroscopy on LHC-II complexes containing violaxanthin or zeaxanthin.
最近，有人提出了一种关于非光化学猝灭（NPQ）的能量依赖成分（qE）的机制，NPQ是绿色植物中的基本光保护机制。在主要捕光复合物LHC-II的结合口袋中，叶黄素被玉米黄质取代可能足以引发有效的叶绿素荧光猝灭。然而，我们的量子化学计算表明，当叶黄素和玉米黄质的几何结构被限制在LHC-II中自然观察到的叶黄素结构时，它们的激发态能量实际上是相同的。因此，由于叶黄素不会猝灭LHC-II，玉米黄质也不应该会。这一理论发现与通过飞秒光谱对含有叶黄素或玉米黄质的LHC-II复合物获得的实验结果非常吻合。
