7DWQ

Photosystem I from a chlorophyll d-containing cyanobacterium Acaryochloris marina

Summary for 7DWQ

• Entry DOI: 10.2210/pdb7dwq/pdb
• EMDB information: 30882
• Descriptor: Photosystem I protein PsaD, Photosystem I protein Psa27, CHLOROPHYLL D, ... (18 entities in total)
• Functional Keywords: photosystem i, reaction center, cryo-em, cyanobacteria, photosynthesis
• Biological source: Acaryochloris marina MBIC11017; More
• Total number of polymer chains: 10
• Total formula weight: 326977.39

Authors

Chen, J.H.,Zhang, X.,Shen, J.R. (deposition date: 2021-01-17, release date: 2021-06-02, Last modification date: 2024-10-16)

Primary citation

Xu, C.,Zhu, Q.,Chen, J.H.,Shen, L.,Yi, X.,Huang, Z.,Wang, W.,Chen, M.,Kuang, T.,Shen, J.R.,Zhang, X.,Han, G.
A unique photosystem I reaction center from a chlorophyll d-containing cyanobacterium Acaryochloris marina.
J Integr Plant Biol, 63:1740-1752, 2021

PubMed Abstract: Photosystem I (PSI) is a large protein supercomplex that catalyzes the light-dependent oxidation of plastocyanin (or cytochrome c ) and the reduction of ferredoxin. This catalytic reaction is realized by a transmembrane electron transfer chain consisting of primary electron donor (a special chlorophyll (Chl) pair) and electron acceptors A , A , and three Fe S clusters, F , F , and F . Here we report the PSI structure from a Chl d-dominated cyanobacterium Acaryochloris marina at 3.3 Å resolution obtained by single-particle cryo-electron microscopy. The A. marina PSI exists as a trimer with three identical monomers. Surprisingly, the structure reveals a unique composition of electron transfer chain in which the primary electron acceptor A is composed of two pheophytin a rather than Chl a found in any other well-known PSI structures. A novel subunit Psa27 is observed in the A. marina PSI structure. In addition, 77 Chls, 13 α-carotenes, two phylloquinones, three Fe-S clusters, two phosphatidyl glycerols, and one monogalactosyl-diglyceride were identified in each PSI monomer. Our results provide a structural basis for deciphering the mechanism of photosynthesis in a PSI complex with Chl d as the dominating pigments and absorbing far-red light.

PubMed: 34002536
DOI: 10.1111/jipb.13113

Experimental method

ELECTRON MICROSCOPY (3.3 Å)