Research
| Title： | Structural and functional insights into the tetrameric photosystem I from heterocyst-forming cyanobacteria |
|---|---|
| First author： | Zheng, Lvqin; Li, Yanbing; Li, Xiying; Zhong, Qinglu; Li, Ningning; Zhang, Kun; Zhang, Yuebin; Chu, Huiying; Ma, Chengying; Li, Guohui; Zhao, Jindong; Gao, Ning |
| Journal： | NATURE PLANTS |
| Years： | 2019 |
| DOI： | 10.1038/s41477-019-0525-6 |
| Abstract： | Two large protein-cofactor complexes, photosystem I and photosystem II, are the central components of photosynthesis in the thylakoid membranes. Here, we report the 2.37-angstrom structure of a tetrameric photosystem I complex from a heterocyst-forming cyanobacterium Anabaena sp. PCC 7120. Four photosystem I monomers, organized in a dimer of dimer, form two distinct interfaces that are largely mediated by specifically orientated polar lipids, such as sulfoquinovosyl diacylglycerol. The structure depicts a more closely connected network of chlorophylls across monomer interfaces than those seen in trimeric PSI from thermophilic cyanobacteria, possibly allowing a more efficient energy transfer between monomers. Our physiological data also revealed a functional link of photosystem I oligomerization to cyclic electron flow and thylakoid membrane organization. |
