Harvesting far-red light: functional integration of chlorophyll f into Photosystem I complexes of Synechococcus sp. PCC 7002
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 RC 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.
|Work Title||Harvesting far-red light: functional integration of chlorophyll f into Photosystem I complexes of Synechococcus sp. PCC 7002|
|Keyword||Photosynthesis, Light Harvesting, Pigments, Time-Resolved Fluorescence, Excitation Energy Transfer|
|License||All rights reserved|
|Publisher Identifier (DOI)||doi:10.1016/j.bbabio.2020.148206|
|Deposited||February 23, 2021 17:42|
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