Locating the missing chlorophylls f in far-red photosystem I
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 chlorophyll f sites, but none among the photochemically active pigments, and thus concluded that chlorophyll f plays no photochemical role. Here, we report two cryo-electron microscopy structures of far-red photosystem I from <i>Chroococcidiopsis thermalis</i> PCC 7203, allowing the assignment of eight chlorophyll f molecules, including the redox active A<sub>-1B</sub>. Simulations of absorption difference spectra induced by charge separation indicated that the experimental spectra can be reproduced only by considering the presence of a chlorophyll f at the A<sub>-1B</sub> site. The chlorophyll f locations, wavelength assignments, and conserved far-red-specific residues provide functional insights for efficient use of long-wavelength photons.
Authors
- Thomas Renger (ORCID: https://orcid.org/0000-0001-9245-3805)
- Benoît Chachuat (ORCID: https://orcid.org/0000-0003-4780-9686)
- Andrea Fantuzzi (ORCID: https://orcid.org/0000-0002-7026-2175)
- Paul Simpson (ORCID: https://orcid.org/0000-0002-9632-555X)
- Jenny Nelson (ORCID: https://orcid.org/0000-0003-1048-1330)
- James W. Murray (ORCID: https://orcid.org/0000-0002-8897-0161)
- Daniel Medranda (ORCID: https://orcid.org/0009-0004-0476-4195)
- A. William Rutherford (ORCID: https://orcid.org/0000-0002-3124-154X)
- Stefania Viola (ORCID: https://orcid.org/0000-0003-0773-8158)
- Geoffry A. Davis (ORCID: https://orcid.org/0000-0002-6964-9196)
- Giovanni Consoli (ORCID: https://orcid.org/0009-0005-8681-9088)
- Marco Sandrin (ORCID: https://orcid.org/0009-0007-0157-4152)
- Fiazall Tufail (ORCID: https://orcid.org/0009-0007-3874-3917)
- Ho Fong Leong (ORCID: https://orcid.org/0009-0005-2058-9574)
- Nicholas Rew (ORCID: https://orcid.org/0009-0005-5851-9846)
- M Hofer
Institutions
- Johannes Kepler University of Linz (AT)
- Institute of Structural and Molecular Biology (GB)
- Imperial College London (GB)
Publication Details
- Journal
- Science
- Published
- 2025-10-09
- DOI
- https://doi.org/10.1126/science.ado6830
- Citations
- 1
- Primary Topic
- Photosynthetic Processes and Mechanisms
- Type
- article
- Field-Weighted Citation Impact
- 0.81