Time-resolved vibrational spectroscopy detects protein-based intermediates in the photosynthetic oxygen-evolving cycle.
Time-resolved vibrational spectroscopy detects protein-based intermediates in the photosynthetic oxygen-evolving cycle.
复制标题
时间分辨振动光谱检测光合作用释氧循环中基于蛋白质的中间体。
DOI：
10.1073/pnas.0600216103
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发表时间：
2006
影响因子：
11.1
通讯作者：
Dyer,RBrian
中科院分区：
文献类型：
--
作者：
Barry,BridgetteA;Cooper,IanB;DeRiso,Antonio;Brewer,ScottH;Vu,DungM;Dyer,RBrian
光系统II(PSII)产生的光合氧负责维持地球上的有氧生命。氧的产生发生在PSII放氧复合体(OEC)，它包含一个四核锰(Mn)簇。反应中心的光诱导电子转移事件导致氧化当量在OEC上积累。氧气的生产需要四个连续的光氧化反应。五个氧化态之间的氧化复杂循环，称为Sn态，其中是指储存的氧化当量的数量。氧在从S3到S0的转变过程中从一种不稳定的中间产物S4状态释放出来。在这份报告中，我们提供了数据，为每个S状态转变期间中间体的产生提供了证据。这些蛋白质衍生的中间体在微秒到毫秒的时间尺度上产生，并在微秒时间尺度上通过时间分辨振动光谱进行检测。我们的结果表明，在从S2到S3和从S3到S0的转变过程中，蛋白质衍生的构象变化或质子转移反应先于Mn氧化还原反应。
Photosynthetic oxygen production by photosystem II (PSII) is responsible for the maintenance of aerobic life on earth. The production of oxygen occurs at the PSII oxygen-evolving complex (OEC), which contains a tetranuclear manganese (Mn) cluster. Photo-induced electron transfer events in the reaction center lead to the accumulation of oxidizing equivalents on the OEC. Four sequential photooxidation reactions are required for oxygen production. The oxidizing complex cycles among five oxidation states, called the Snstates, wherenrefers to the number of oxidizing equivalents stored. Oxygen release occurs during the S3-to-S0transition from an unstable intermediate, known as the S4state. In this report, we present data providing evidence for the production of an intermediate during each S state transition. These protein-derived intermediates are produced on the microsecond to millisecond time scale and are detected by time-resolved vibrational spectroscopy on the microsecond time scale. Our results suggest that a protein-derived conformational change or proton transfer reaction precedes Mn redox reactions during the S2-to-S3and S3-to-S0transitions.