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.
Original language | English (US) |
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Article number | 4650 |
Journal | Nature communications |
Volume | 14 |
Issue number | 1 |
DOIs | |
State | Published - Dec 2023 |
ASJC Scopus subject areas
- General Chemistry
- General Biochemistry, Genetics and Molecular Biology
- General Physics and Astronomy
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Energetic robustness to large scale structural dynamics in a photosynthetic supercomplex
Harris, D. (Contributor), Toporik, H. (Contributor), Schlau-Cohen, G. S. (Contributor) & Mazor, Y. (Contributor), Protein Data Bank (PDB), May 17 2023
DOI: 10.2210/pdb7UMH, https://www.wwpdb.org/pdb?id=pdb_00007umh
Dataset