7DR1

Structure of Wild-type PSI monomer2 from Cyanophora paradoxa

Summary for 7DR1

• Entry DOI: 10.2210/pdb7dr1/pdb
• EMDB information: 30821
• Descriptor: Photosystem I P700 chlorophyll a apoprotein A1, Photosystem I reaction center subunit XII, CHLOROPHYLL A ISOMER, ... (17 entities in total)
• Functional Keywords: photosystem i, electron transport, photosynthesis
• Biological source: Cyanophora paradoxa; More
• Total number of polymer chains: 10
• Total formula weight: 340742.19

Authors

Kato, K.,Nagao, R.,Akita, F.,Miyazaki, N.,Shen, J.R. (deposition date: 2020-12-25, release date: 2022-02-16, Last modification date: 2025-11-19)

Primary citation

Kato, K.,Nagao, R.,Ueno, Y.,Yokono, M.,Suzuki, T.,Jiang, T.Y.,Dohmae, N.,Akita, F.,Akimoto, S.,Miyazaki, N.,Shen, J.R.
Structure of a tetrameric photosystem I from a glaucophyte alga Cyanophora paradoxa.
Nat Commun, 13:1679-1679, 2022

PubMed Abstract: Photosystem I (PSI) is one of the two photosystems functioning in light-energy harvesting, transfer, and electron transfer in photosynthesis. However, the oligomerization state of PSI is variable among photosynthetic organisms. We present a 3.8-Å resolution cryo-electron microscopic structure of tetrameric PSI isolated from the glaucophyte alga Cyanophora paradoxa, which reveals differences with PSI from other organisms in subunit composition and organization. The PSI tetramer is organized in a dimer of dimers with a C2 symmetry. Unlike cyanobacterial PSI tetramers, two of the four monomers are rotated around 90°, resulting in a completely different pattern of monomer-monomer interactions. Excitation-energy transfer among chlorophylls differs significantly between Cyanophora and cyanobacterial PSI tetramers. These structural and spectroscopic features reveal characteristic interactions and excitation-energy transfer in the Cyanophora PSI tetramer, suggesting that the Cyanophora PSI could represent a turning point in the evolution of PSI from prokaryotes to eukaryotes.

PubMed: 35354806
DOI: 10.1038/s41467-022-29303-7

Experimental method

ELECTRON MICROSCOPY (3.2 Å)