Wang Weiwei, Liu Yanting, Gu Jiayi, An Shaoya, Ma Cheng, Gao Haichun, Jiao Nianzhi, Shen Jian-Ren, Beatty John Thomas, Koblížek Michal, Zhang Xing, Zheng Qiang, Chen Jing-Hua
College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, Fujian, 361005, China.
Adv Sci (Weinh). 2025 May;12(18):e2413456. doi: 10.1002/advs.202413456. Epub 2025 Mar 20.
The reaction center-light harvesting 1 (RC-LH1) complex converts solar energy into electrical energy, driving the initiation of photosynthesis. The authors present a cryo-electron microscopy structure of the RC-LH1 isolated from a marine photoheterotrophic bacterium Dinoroseobacter shibae. The RC comprises four subunits, including a three-heme cytochrome (Cyt) c protein, and is surrounded by a closed LH ring composed of 17 pairs of antenna subunits. Notably, a novel subunit with an N-terminal "helix-turn-helix" motif embedded in the gap between the RC and the LH ring is identified. The purified RC-LH1 complex exhibits high stability in solutions containing Mg or Ca. The periplasmic Cyt c is predicted to bind at the junction between the Cyt subunit and the membrane plane, enabling electron transfer from Cyt c to the proximal heme of the tri-heme Cyt, and subsequently to the special pair of bacteriochlorophylls. These findings provide structural insights into the efficient energy and electron transfer processes within a distinct type of RC-LH1, and shed light on evolutionary adaptations of photosynthesis.
反应中心-光捕获1（RC-LH1）复合体将太阳能转化为电能，驱动光合作用的启动。作者展示了从海洋光异养细菌希氏玫瑰杆菌中分离出的RC-LH1的冷冻电子显微镜结构。RC由四个亚基组成，包括一个含三个血红素的细胞色素（Cyt）c蛋白，并被一个由17对天线亚基组成的封闭LH环包围。值得注意的是，在RC和LH环之间的间隙中发现了一个具有N端“螺旋-转角-螺旋”基序的新亚基。纯化的RC-LH1复合体在含有镁或钙的溶液中表现出高稳定性。预测周质Cyt c结合在Cyt亚基与膜平面的交界处，使电子从Cyt c转移到三血红素Cyt的近端血红素，随后转移到特殊的一对细菌叶绿素。这些发现为一种独特类型的RC-LH1内高效的能量和电子转移过程提供了结构见解，并揭示了光合作用的进化适应性。
