The PSI-H subunit of photosystem I is essential for state transitions in plant photosynthesis
The PSI-H subunit of photosystem I is essential for state transitions in plant photosynthesis
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DOI：
10.1038/35046121
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发表时间：
2000-11-30
期刊：
影响因子：
64.8
通讯作者：
Scheller, HV
中科院分区：
文献类型：
--
作者：
Lunde, C;Jensen, PE;Scheller, HV
植物的光合作用涉及两个负责将光能转化为氧化还原过程的光系统。 PSI 和 PSII 光系统主要串联运行，因此必须平衡它们的激发以优化光合作用性能(1)。当植物暴露在有利于 PSII 或 PSI 的光照下时，它们可以将激发重新分配到限光光系统。光照的长期变化会导致光系统化学计量的变化(2,3)。相反，状态转换是一种动态机制，使植物能够快速响应光照变化。当 PSII 受到青睐时（状态 2），类囊体中的氧化还原条件会发生变化并导致蛋白激酶激活 (4-6)。该激酶磷酸化主要的光捕获复合物 (LHCII)，并且移动天线复合物与 PSII 分离。目前尚不清楚状态 2 中 LHCII 与 PSI 的连接在状态转换中是否重要。在这里，我们表明，在缺乏特定 PSI 亚基的情况下，PSI-H、LHCII 无法将能量转移到 PSI，并且状态转换受到损害。
Photosynthesis in plants involves two photosystems responsible for converting light energy into redox processes. The photosystems, PSI and PSII, operate largely in series, and therefore their excitation must be balanced in order to optimize photosynthetic performance(1). When plants are exposed to illumination favouring either PSII or PSI they can redistribute excitation towards the light-limited photosystem. Long-term changes in illumination lead to changes in photosystem stoichiometry(2,3). In contrast, state transition is a dynamic mechanism that enables plants to respond rapidly to changes in illumination. When PSII is favoured (state 2), the redox conditions in the thylakoids change and result in activation of a protein kinase(4-6). The kinase phosphorylates the main light-harvesting complex (LHCII) and the mobile antenna complex is detached from PSII. It has not been clear if attachment of LHCII to PSI in state 2 is important in state transitions. Here we show that in the absence of a specific PSI subunit, PSI-H, LHCII cannot transfer energy to PSI, and state transitions are impaired.