Structure and assembly mechanism of plant C2S2M2-type PSII-LHCII supercomplex

Detailed look at photosynthetic complex PSII

30 April 2018

A high-resolution snapshot of the molecular supercomplex at the heart of photosynthesis, known as photosystem II (PSII), offers insights into its light-harvesting mechanisms and their regulation.

Researchers at the University of Chinese Academy of Sciences and other Chinese institutes used cryo-electron microscopy to determine the structure of a low-light version of PSII from pea plants. The PSII complex, which includes more than 20 subunits, consists of a core and several peripheral antennae, known as light-harvesting complexes II (LHCII), variation in which help plants adapt to different light levels.

The structural analysis revealed the connections and interactions between subunits. The team found that the antennae are highly mobile, which may facilitate adjustment of LHCII to regulate the complex’s light-harvesting capacity. The high resolution of the structure and the fact that it included the entire pigment network also enabled the team to reconstruct the energy transfer pathways in PSII. 

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References

1. Science 357, 815-820 (2017). doi: 10.1126/science.aan0327