Nature Communications (Jul 2023)

Cryo-EM and femtosecond spectroscopic studies provide mechanistic insight into the energy transfer in CpcL-phycobilisomes

  • Lvqin Zheng,
  • Zhengdong Zhang,
  • Hongrui Wang,
  • Zhenggao Zheng,
  • Jiayu Wang,
  • Heyuan Liu,
  • Hailong Chen,
  • Chunxia Dong,
  • Guopeng Wang,
  • Yuxiang Weng,
  • Ning Gao,
  • Jindong Zhao

DOI
https://doi.org/10.1038/s41467-023-39689-7
Journal volume & issue
Vol. 14, no. 1
pp. 1 – 10

Abstract

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Abstract Phycobilisomes (PBS) are the major light harvesting complexes of photosynthesis in the cyanobacteria and red algae. CpcL-PBS is a type of small PBS in cyanobacteria that transfers energy directly to photosystem I without the core structure. Here we report the cryo-EM structure of the CpcL-PBS from the cyanobacterium Synechocystis sp. PCC 6803 at 2.6-Å resolution. The structure shows the CpcD domain of ferredoxin: NADP+ oxidoreductase is located at the distal end of CpcL-PBS, responsible for its attachment to PBS. With the evidence of ultrafast transient absorption and fluorescence spectroscopy, the roles of individual bilins in energy transfer are revealed. The bilin 1Iβ82 2 located near photosystem I has an enhanced planarity and is the red-bilin responsible for the direct energy transfer to photosystem I.