7UMH

Energetic robustness to large scale structural dynamics in a photosynthetic supercomplex

This is a non-PDB format compatible entry.

Summary for 7UMH

• Entry DOI: 10.2210/pdb7umh/pdb
• EMDB information: 26601
• Descriptor: Photosystem I P700 chlorophyll a apoprotein A1, Photosystem I reaction center subunit XI, Photosystem I reaction center subunit XII, ... (25 entities in total)
• Functional Keywords: photosystem i, antenna, cyanobacteria, photosynthesis, membrane complex
• Biological source: Synechocystis sp. PCC 6803; More
• Total number of polymer chains: 51
• Total formula weight: 2073405.90

Authors

Harris, D.,Toporik, H.,Schlau-Cohen, G.S.,Mazor, Y. (deposition date: 2022-04-07, release date: 2023-05-17, Last modification date: 2023-08-16)

Primary citation

Harris, D.,Toporik, H.,Schlau-Cohen, G.S.,Mazor, Y.
Energetic robustness to large scale structural fluctuations in a photosynthetic supercomplex.
Nat Commun, 14:4650-4650, 2023

PubMed Abstract: Photosynthetic organisms transport and convert solar energy with near-unity quantum efficiency using large protein supercomplexes held in flexible membranes. The individual proteins position chlorophylls to tight tolerances considered critical for fast and efficient energy transfer. The variability in protein organization within the supercomplexes, and how efficiency is maintained despite variability, had been unresolved. Here, we report on structural heterogeneity in the 2-MDa cyanobacterial PSI-IsiA photosynthetic supercomplex observed using Cryo-EM, revealing large-scale variances in the positions of IsiA relative to PSI. Single-molecule measurements found efficient IsiA-to-PSI energy transfer across all conformations, along with signatures of transiently decoupled IsiA. Structure based calculations showed that rapid IsiA-to-PSI energy transfer is always maintained, and even increases by three-fold in rare conformations via IsiA-specific chls. We postulate that antennae design mitigates structural fluctuations, providing a mechanism for robust energy transfer in the flexible membrane.

PubMed: 37532717
DOI: 10.1038/s41467-023-40146-8

Experimental method

ELECTRON MICROSCOPY (2.6 Å)