Breaking the red-limit: efficient trapping of long-wavelength excitations in chlorophyll f-containing Photosystem I.

Photosystem I (PSI) converts photons into electrons with a nearly 100% quantum efficiency. Its minimal energy requirement for photochemistry corresponds to a 700 nm photon, representing the well-known ‘red limit’ of oxygenic photosynthesis. Recently, some cyanobacteria containing the red-shifted pigment chlorophyll f have been shown to harvest photons up to 800 nm. To investigate the mechanism responsible for converting such low-energy photons, we applied steady-state and time-resolved spectroscopies to the chlorophyll f-containing PSI and chlorophyll a-only PSI of various cyanobacterial strains. Chlorophyll f-containing PSI displays a less optimal energetic connectivity between its pigments. Nonetheless, it consistently traps long-wavelength excitations with a surprisingly high efficiency, which can only be achieved by lowering the energy required for photochemistry, i.e. by ‘breaking the red limit’. A mechanism involving charge separation via a low-energy charge transfer state is proposed to reconcile this finding with the available structural data that show that no chlorophyll f is involved in photochemistry.

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Work Title Breaking the red-limit: efficient trapping of long-wavelength excitations in chlorophyll f-containing Photosystem I.
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Open Access
Creators
  1. Martijn Tros
  2. Vincenzo Mascoli
  3. Gaozhong Shen
  4. Ming Yang Ho
  5. Luca Bersanini
  6. Christopher J. Gisriel
  7. Donald A. Bryant
  8. Roberta Croce
License In Copyright (Rights Reserved)
Work Type Article
Publisher
  1. Chem
Publication Date November 19, 2020
Publisher Identifier (DOI)
  1. https://doi.org/10.1016/j.chempr.2020.10.024
Deposited November 16, 2021

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  • Created
  • Added 2020_Tros_et_al._Chem_MS_+_Suppl.pdf
  • Added Creator Martijn Tros
  • Added Creator Vincenzo Mascoli
  • Added Creator Gaozhong Shen
  • Added Creator Ming Yang Ho
  • Added Creator Luca Bersanini
  • Added Creator Christopher J. Gisriel
  • Added Creator Donald A. Bryant
  • Added Creator Roberta Croce
  • Published
  • Updated
  • Updated