Harvesting far-red light: Functional integration of chlorophyll f into Photosystem I complexes of Synechococcus sp. PCC 7002

Martijn Tros, Luca Bersanini, Gaozhong Shen, Ming Yang Ho, Ivo H.M. van Stokkum, Donald A. Bryant, Roberta Croce*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


The heterologous expression of the far-red absorbing chlorophyll (Chl) f in organisms that do not synthesize this pigment has been suggested as a viable solution to expand the solar spectrum that drives oxygenic photosynthesis. In this study, we investigate the functional binding of Chl f to the Photosystem I (PSI) of the cyanobacterium Synechococcus 7002, which has been engineered to express the Chl f synthase gene. By optimizing growth light conditions, one-to-four Chl f pigments were found in the complexes. By using a range of spectroscopic techniques, isolated PSI trimeric complexes were investigated to determine how the insertion of Chl f affects excitation energy transfer and trapping efficiency. The results show that the Chls f are functionally connected to the reaction center of the PSI complex and their presence does not change the overall pigment organization of the complex. Chl f substitutes Chl a (but not the Chl a red forms) while maintaining efficient energy transfer within the PSI complex. At the same time, the introduction of Chl f extends the photosynthetically active radiation of the new hybrid PSI complexes up to 750 nm, which is advantageous in far-red light enriched environments. These conclusions provide insights to engineer the photosynthetic machinery of crops to include Chl f and therefore increase the light-harvesting capability of photosynthesis.

Original languageEnglish
Article number148206
Pages (from-to)1-9
Number of pages8
JournalBiochimica et Biophysica Acta - Bioenergetics
Issue number8
Early online date17 Apr 2020
Publication statusPublished - 1 Aug 2020


This work was supported by the Dutch Organization for Scientific Research via a TOP grant ( 714.018.001 ) to R.C. L.B was supported by the EMBO long-term fellowship (EMBO ALTF 292-2017 ). DAB gratefully acknowledges support from the U. S. National Science Foundation ( MCB-1613022 ). This research was also conducted under the auspices of the Photosynthetic Antenna Research Center (PARC), an Energy Frontier Research Center funded by the DOE , Office of Science, Office of Basic Energy Sciences under Award Number DE-SC 0001035 (DAB).

FundersFunder number
National Science FoundationMCB-1613022
U.S. Department of Energy
Office of Science
Basic Energy SciencesDE-SC 0001035
Nederlandse Organisatie voor Wetenschappelijk Onderzoek714.018.001, EMBO ALTF 292-2017


    • Excitation energy transfer
    • Light harvesting
    • Photosynthesis
    • Pigments
    • Time-resolved fluorescence


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