State transitions in Chlamydomonas reinhardtii strongly modulate the functional size of photosystem II but not of photosystem I
State transitions in Chlamydomonas reinhardtii strongly modulate the functional size of photosystem II but not of photosystem I
复制标题
莱茵衣藻的状态转换强烈调节光系统 II 的功能大小，但不调节光系统 I 的功能大小
DOI：
10.1073/pnas.1319164111
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
H. van Amerongen
中科院分区：
文献类型：
--
作者：
Caner Ünlü;B. Drop;R. Croce;H. van Amerongen
为了优化光合作用性能，大多数放氧生物能够在光系统I和II之间穿梭捕光色素蛋白复合物。这些光系统串联工作，将光能转化为化学能。人们普遍认为，80%的捕光复合物参与了光合作用研究的模式生物莱茵衣藻的重组。然而，在本文中，我们证明，这样一个大的重塑不会发生。捕光复合物确实可以从光系统II分离，但只有一小部分随后连接到光系统I，并证明了这是如何导致在高光条件下的光保护。这一现象对我们思考光合作用效率调节的方式具有重要意义。植物和绿色藻类通过平衡光系统I和II吸收的光量，在变化的光照条件下优化光合作用。这些光系统串联工作，从水中提取电子并将NADP+还原为NADPH。捕光复合物（LHC）负责通过在称为状态转换的过程中从一个光系统移动到另一个光系统来维持平衡。在绿色的莱茵衣藻（Chlamyeliumreinhardtii）中，一种光合模式生物，状态转换被认为涉及80%的LHC。在这里，我们证明了皮秒荧光光谱的C。在reinhardtii细胞中，尽管LHC确实在状态2条件下从光系统II分离，但只有一部分附着到光系统I。分离的天线复合物通过缩短激发态寿命而免受光损伤。讨论了从状态1到状态2的转换如何保护C。reinhardtii在高光条件下的生长以及这与植物中的情况有何不同。
Significance To optimize their photosynthetic performance, most oxygen-evolving organisms are able to shuttle light-harvesting pigment–protein complexes between photosystems I and II. These photosystems work in series to transform light energy into chemical energy. It is generally accepted that 80% of the light-harvesting complexes is participating in the reorganization in the green alga Chlamydomonas reinhardtii, a model organism for photosynthesis research. However, in the present paper, we demonstrate that such a large remodeling does not occur. Light-harvesting complexes can indeed detach from photosystem II, but only a small fraction subsequently attaches to photosystem I, and it is demonstrated how this leads to photoprotection in high-light conditions. This phenomenon has significant implications for our way of thinking about the efficiency regulation in photosynthesis. Plants and green algae optimize photosynthesis in changing light conditions by balancing the amount of light absorbed by photosystems I and II. These photosystems work in series to extract electrons from water and reduce NADP+ to NADPH. Light-harvesting complexes (LHCs) are held responsible for maintaining the balance by moving from one photosystem to the other in a process called state transitions. In the green alga Chlamydomonas reinhardtii, a photosynthetic model organism, state transitions are thought to involve 80% of the LHCs. Here, we demonstrate with picosecond-fluorescence spectroscopy on C. reinhardtii cells that, although LHCs indeed detach from photosystem II in state 2 conditions, only a fraction attaches to photosystem I. The detached antenna complexes become protected against photodamage via shortening of the excited-state lifetime. It is discussed how the transition from state 1 to state 2 can protect C. reinhardtii in high-light conditions and how this differs from the situation in plants.
影响因子：
4.3
作者：
Holzwarth, Alfred R.;Lenk, Dagmar;Jahns, Peter
通讯作者：
Jahns, Peter