Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK.
Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK; Centre for Cell Imaging, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK.
Mol Plant. 2017 Nov 6;10(11):1434-1448. doi: 10.1016/j.molp.2017.09.019. Epub 2017 Oct 7.
The structural dynamics and flexibility of cell membranes play fundamental roles in the functions of the cells, i.e., signaling, energy transduction, and physiological adaptation. The cyanobacterial thylakoid membrane represents a model membrane that can conduct both oxygenic photosynthesis and respiration simultaneously. In this study, we conducted direct visualization of the global organization and mobility of photosynthetic complexes in thylakoid membranes from a model cyanobacterium, Synechococcus elongatus PCC 7942, using high-resolution atomic force, confocal, and total internal reflection fluorescence microscopy. We visualized the native arrangement and dense packing of photosystem I (PSI), photosystem II (PSII), and cytochrome (Cyt) bf within thylakoid membranes at the molecular level. Furthermore, we functionally tagged PSI, PSII, Cyt bf, and ATP synthase individually with fluorescent proteins, and revealed the heterogeneous distribution of these four photosynthetic complexes and determined their dynamic features within the crowding membrane environment using live-cell fluorescence imaging. We characterized red light-induced clustering localization and adjustable diffusion of photosynthetic complexes in thylakoid membranes, representative of the reorganization of photosynthetic apparatus in response to environmental changes. Understanding the organization and dynamics of photosynthetic membranes is essential for rational design and construction of artificial photosynthetic systems to underpin bioenergy development. Knowledge of cyanobacterial thylakoid membranes could also be extended to other cell membranes, such as chloroplast and mitochondrial membranes.
细胞膜的结构动力学和柔韧性在细胞功能中起着基础性作用，例如信号转导、能量转导和生理适应。蓝细菌类囊体膜是一种可以同时进行产氧光合作用和呼吸作用的模型膜。在这项研究中，我们使用高分辨率原子力显微镜、共聚焦显微镜和全内反射荧光显微镜，对来自模式蓝细菌集胞藻 PCC 7942 的类囊体膜中的光合复合物的整体组织和流动性进行了直接可视化。我们在分子水平上可视化了类囊体膜中光系统 I（PSI）、光系统 II（PSII）和细胞色素（Cyt）bf 的天然排列和密集堆积。此外，我们分别用荧光蛋白对 PSI、PSII、Cyt bf 和 ATP 合酶进行功能标记，并使用活细胞荧光成像揭示了这四个光合复合物在拥挤的膜环境中的异质分布及其动态特征。我们对类囊体膜中光诱导的聚类定位和光合复合物的可调节扩散进行了表征，这代表了光合作用器对环境变化的重新组织。了解光合膜的组织和动力学对于合理设计和构建人工光合系统以支持生物能源发展至关重要。对蓝细菌类囊体膜的了解也可以扩展到其他细胞膜，如叶绿体和线粒体膜。
