Identification of distinct pH-and zeaxanthin-dependent quenching in LHCSR3 from Chlamydomonas reinhardtii
- Massachusetts Institute of Technology, United States
- University of Verona, Italy
- Hanyang University, Republic of Korea
Abstract
Under high light, oxygenic photosynthetic organisms avoid photodamage by thermally dissipating absorbed energy, which is called non-photochemical quenching. In green algae, a chlorophyll and carotenoid-binding protein, light-harvesting complex stress-related (LHCSR3), detects excess energy via a pH drop and serves as a quenching site. Using a combined in vivo and in vitro approach, we investigated quenching within LHCSR3 from Chlamydomonas reinhardtii. In vitro two distinct quenching processes, individually controlled by pH and zeaxanthin, were identified within LHCSR3. The pH-dependent quenching was removed within a mutant LHCSR3 that lacks the residues that are protonated to sense the pH drop. Observation of quenching in zeaxanthin-enriched LHCSR3 even at neutral pH demonstrated zeaxanthin-dependent quenching, which also occurs in other light-harvesting complexes. Either pH- or zeaxanthin-dependent quenching prevented the formation of damaging reactive oxygen species, and thus the two quenching processes may together provide different induction and recovery kinetics for photoprotection in a changing environment.
Data availability
Source data files have been provided for Figures 1A and 3.Single-molecule photon emission data for Figures 1B-D and 2 has been deposited on Zenodo.org and is available at 10.5281/zenodo.4306869
Article and author information
Author details
Gabriela S Schlau-Cohen
Funding
Human Frontiers Science Program (RGY0076)
- Gabriela S Schlau-Cohen
National Science Foundation (CHE-1740645)
- Gabriela S Schlau-Cohen
H2020 European Research Council (679814)
- Matteo Ballottari
Korea Ministry of Science and ICT (NRF-2014M1A8A1049273)
- EonSeon Jin
Arnold and Mabel Beckman Foundation (Postdoctoral Fellowship)
- Julianne M Troiano
National Science Foundation (Graduate Research Fellowship)
- Raymundo Moya
Arnold and Mabel Beckman Foundation (Beckman Young Investigator)
- Gabriela S Schlau-Cohen
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2021, Troiano et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Identification of distinct pH-and zeaxanthin-dependent quenching in LHCSR3 from Chlamydomonas reinhardtii
eLife 10:e60383.
https://doi.org/10.7554/eLife.60383
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