Dynamical and allosteric regulation of photoprotection in light harvesting complex II

Hao Li, Yingjie Wang, Manping Ye, Shanshan Li, Deyong Li, Haisheng Ren, Mohan Wang, Luchao Du, Heng Li, Gianluigi Veglia, Jiali Gao, Yuxiang Weng

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Major light-harvesting complex of photosystem II (LHCII) plays a dual role in light-harvesting and excited energy dissipation to protect photodamage from excess energy. The regulatory switch is induced by increased acidity, temperature or both. However, the molecular origin of the protein dynamics at the atomic level is still unknown. We carried out temperature-jump time-resolved infrared spectroscopy and molecular dynamics simulations to determine the energy quenching dynamics and conformational changes of LHCII trimers. We found that the spontaneous formation of a pair of local α-helices from the 3 10-helix E/loop and the C-terminal coil of the neighboring monomer, in response to the increased environmental temperature and/or acidity, induces a scissoring motion of transmembrane helices A and B, shifting the conformational equilibrium to a more open state, with an increased angle between the associated carotenoids. The dynamical allosteric conformation change leads to close contacts between the first excited state of carotenoid lutein 1 and chlorophyll pigments, facilitating the fluorescence quenching. Based on these results, we suggest a unified mechanism by which the LHCII trimer controls the dissipation of excess excited energy in response to increased temperature and acidity, as an intrinsic result of intense sun light in plant photosynthesis.

Original languageEnglish (US)
Pages (from-to)1121-1133
Number of pages13
JournalScience China Chemistry
Issue number8
StatePublished - Aug 1 2020

Bibliographical note

Publisher Copyright:
© 2020, Science China Press and Springer-Verlag GmbH Germany, part of Springer Nature.


  • FTIR
  • LHCII photoprotection
  • T-jump
  • conformational dynamics and allostery
  • excited energy transfer
  • fluorescence quenching
  • protein switch


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