Dissecting the native architecture and dynamics of cyanobacterial photosynthetic machinery
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The structural dynamics and flexibility of cell membranes play fundamental roles in the functions of the cell, i.e. signaling, electron transduction, and physiological adaptation. The cyanobacterial thylakoid membrane represents a model membrane that can conduct both oxygenic photosynthesis and respiration simultaneously. Here, 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) b6f within thylakoid membranes at the molecular level. Furthermore, we functionally tagged PSI, PSII, Cyt b6f and ATP synthase individually with fluorescent proteins. Using live-cell fluorescence imaging, we revealed the heterogeneous distribution of the four photosynthetic complexes and determined their dynamic features within the crowding membrane environment. 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 be extended to other cell membranes, such as chloroplast and mitochondrial membranes.
AuthorsCasella, S; Huang, F; Mason, D; Zhao, G-Y; Johnson, GN; MULLINEAUX, CW; Liu, L-N
- College Publications