Locating the missing chlorophylls f in far-red photosystem I
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
The discovery of chlorophyll f-containing photosystems, with their long-wavelength photochemistry, represented a distinct, low-energy paradigm for oxygenic photosynthesis. Structural studies on chlorophyll f-containing photosystem I could identify some chlorophylls f sites, but none among the photochemically active pigments and concluded that chlorophyll f plays no photochemical role. Here, we report two cryo-EM structures of far-red PSI from Chroococcidiopsis thermalis PCC 7203, allowing the assignment of eight chlorophylls f molecules, including the redox active A-1B. Simulations of absorption difference spectra induced by charge separation indicate that the experimental spectra can be reproduced only by considering the presence of a chlorophyll f at the A-1B site. The chlorophyll f locations, wavelength assignments, and conserved far-red-specific residues provide functional insights for efficient use of long wavelength photons.
Date Issued
2025-12-11
Date Acceptance
2025-09-04
Citation
Science, 2025, 390 (6778)
ISSN
0036-8075
Publisher
American Association for the Advancement of Science (AAAS)
Start Page
eado6830
Journal / Book Title
Science
Volume
390
Issue
6778
Copyright Statement
Copyright © 2025 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. This is the author’s accepted manuscript made available under a CC-BY licence in accordance with Imperial’s Research Publications Open Access policy (www.imperial.ac.uk/oa-policy)
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/41066538
Publication Status
Published
Coverage Spatial
United States
Article Number
eado6830
Date Publish Online
2025-10-09