Low-Energy Chlorophylls in Fucoxanthin Chlorophyll a/c-Binding Protein Conduct Excitation Energy Transfer to Photosystem I in Diatoms

2018 ◽  
Vol 123 (1) ◽  
pp. 66-70 ◽  
Author(s):  
Ryo Nagao ◽  
Makio Yokono ◽  
Yoshifumi Ueno ◽  
Jian-Ren Shen ◽  
Seiji Akimoto
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
Chlorophyll A ◽  
Photosystem I ◽  
Binding Protein ◽  
Excitation Energy Transfer ◽  
Low Energy

pH-Induced Regulation of Excitation Energy Transfer in the Cyanobacterial Photosystem I Tetramer

2020 ◽  
Vol 124 (10) ◽  
pp. 1949-1954 ◽  
Author(s):  
Ryo Nagao ◽  
Makio Yokono ◽  
Yoshifumi Ueno ◽  
Tian-Yi Jiang ◽  
Jian-Ren Shen ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
Photosystem I ◽  
Excitation Energy Transfer

scholarly journals Structure of a cyanobacterial photosystem I surrounded by octadecameric IsiA antenna proteins

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Fusamichi Akita ◽  
Ryo Nagao ◽  
Koji Kato ◽  
Yoshiki Nakajima ◽  
Makio Yokono ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
Photosystem I ◽  
Fluorescence Spectra ◽  
Protein A ◽  
Excitation Energy Transfer ◽  
Electron Microscopic ◽  
Time Resolved ◽  
Closed Ring ◽  
Membrane Spanning

AbstractIron-stress induced protein A (IsiA) is a chlorophyll-binding membrane-spanning protein in photosynthetic prokaryote cyanobacteria, and is associated with photosystem I (PSI) trimer cores, but its structural and functional significance in light harvesting remains unclear. Here we report a 2.7-Å resolution cryo-electron microscopic structure of a supercomplex between PSI core trimer and IsiA from a thermophilic cyanobacterium Thermosynechococcus vulcanus. The structure showed that 18 IsiA subunits form a closed ring surrounding a PSI trimer core. Detailed arrangement of pigments within the supercomplex, as well as molecular interactions between PSI and IsiA and among IsiAs, were resolved. Time-resolved fluorescence spectra of the PSI–IsiA supercomplex showed clear excitation-energy transfer from IsiA to PSI, strongly indicating that IsiA functions as an energy donor, but not an energy quencher, in the supercomplex. These structural and spectroscopic findings provide important insights into the excitation-energy-transfer and subunit assembly mechanisms in the PSI–IsiA supercomplex.

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