Structure of the maize photosystem I supercomplex with light-harvesting complexes I and II
Structure of the maize photosystem I supercomplex with light-harvesting complexes I and II
复制标题
具有光捕获复合物 I 和 II 的玉米光系统 I 超复合物的结构
DOI：
10.1126/science.aat1156
复制
发表时间：
2018-06-08
期刊：
影响因子：
56.9
通讯作者：
Li, Mei
中科院分区：
文献类型：
--
作者：
Pan, Xiaowei;Ma, Jun;Li, Mei
天线开关合作伙伴在阴凉处一个阴天或遮蔽的树木造成波动的光，可以摆脱平衡的能量流在植物光系统I和II（PSI和PSII）。Pan等人解决了与两种捕光复合物（LHC）结合的PSI的结构。一个LHC与PSI永久相连。另一个LHC在最佳条件下将光能传递给PSII，但在通过一种激酶磷酸化后可以切换到PSI相关状态，该激酶可以感知叶绿体的氧化还原环境。LHC在光系统之间的运动有助于维持均匀的能量通量。在连接PSI核心和每个LHC的结构中可以看到两个含叶绿素的亚基。《科学》，本期第1109页，天线蛋白重新排列，以平衡波动光环境中光系统的能量流。植物调节光合光捕获以维持进入光系统I和II（PSI和PSII）的平衡能量通量。在有利于PSII激发的光条件下，PSII天线，捕光复合物II（LHCII）被磷酸化，并与PSI核心和PSI天线，捕光复合物I（LHCI）形成超复合物。然后LHCI和LHCII都将激发能转移到PSI核心。我们报道了玉米PSI-LHCI-LHCII的结构，揭示了LHCII和PSI之间的识别位点。PSI亚基PsaN和PsaO分别在PSI-LHCI界面和PSI-LHCII界面处观察到。每个亚基通过一对叶绿素分子将激发传递到PSI核心，从而揭示了天线和PSI核心之间的能量转移的先前看不见的路径。
Antenna switches partners in the shade A cloudy day or an overshadowing tree causes fluctuations in light that can throw off the balance of energy flow in plant photosystems I and II (PSI and PSII). Pan et al. solved structures of PSI bound to two light-harvesting complexes (LHCs). One LHC is permanently associated with PSI. The other LHC delivers light energy to PSII under optimal conditions but can switch to a PSI-associated state after phosphorylation by a kinase that senses the redox environment of the chloroplast. The movement of LHCs between the photosystems helps maintain even energy flux. Two chlorophyll-containing subunits are visible in the structure that connect the PSI core to each LHC. Science, this issue p. 1109 Antenna proteins rearrange to balance energy flow to photosystems in fluctuating-light environments. Plants regulate photosynthetic light harvesting to maintain balanced energy flux into photosystems I and II (PSI and PSII). Under light conditions favoring PSII excitation, the PSII antenna, light-harvesting complex II (LHCII), is phosphorylated and forms a supercomplex with PSI core and the PSI antenna, light-harvesting complex I (LHCI). Both LHCI and LHCII then transfer excitation energy to the PSI core. We report the structure of maize PSI-LHCI-LHCII solved by cryo–electron microscopy, revealing the recognition site between LHCII and PSI. The PSI subunits PsaN and PsaO are observed at the PSI-LHCI interface and the PSI-LHCII interface, respectively. Each subunit relays excitation to PSI core through a pair of chlorophyll molecules, thus revealing previously unseen paths for energy transfer between the antennas and the PSI core.