The structure of a red-shifted photosystem I reveals a red site in the core antenna

Hila Toporik, Anton Khmelnitskiy, Zachary Dobson, Reece Riddle, Dewight Williams, Su Lin, Ryszard Jankowiak, Yuval Mazor*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Photosystem I coordinates more than 90 chlorophylls in its core antenna while achieving near perfect quantum efficiency. Low energy chlorophylls (also known as red chlorophylls) residing in the antenna are important for energy transfer dynamics and yield, however, their precise location remained elusive. Here, we construct a chimeric Photosystem I complex in Synechocystis PCC 6803 that shows enhanced absorption in the red spectral region. We combine Cryo-EM and spectroscopy to determine the structurefunction relationship in this red-shifted Photosystem I complex. Determining the structure of this complex reveals the precise architecture of the low energy site as well as large scale structural heterogeneity which is probably universal to all trimeric Photosystem I complexes. Identifying the structural elements that constitute red sites can expand the absorption spectrum of oxygenic photosynthetic and potentially modulate light harvesting efficiency.

Original languageAmerican English
Article number5279
JournalNature Communications
Issue number1
StatePublished - 1 Dec 2020
Externally publishedYes

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