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Nat Chem Biol. 2015 Apr;11(4):287-91. doi: 10.1038/nchembio.1755. Epub 2015 Feb 23.

Mechanism of photoprotection in the cyanobacterial ancestor of plant antenna proteins.

Author information

1
Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic.
2
1] Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic. [2] Institute of Microbiology, Academy of Sciences of the Czech Republic, Třeboň, Czech Republic.
3
1] Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic. [2] Biology Centre, Institute of Plant Molecular Biology, Academy of Sciences of the Czech Republic, České Budějovice, Czech Republic.

Abstract

Plants collect light for photosynthesis using light-harvesting complexes (LHCs)-an array of chlorophyll proteins that are able to reversibly switch from harvesting to energy-dissipation mode to prevent damage of the photosynthetic apparatus. LHC antennae as well as other members of the LHC superfamily evolved from cyanobacterial ancestors called high light-inducible proteins (Hlips). Here, we characterized a purified Hlip family member HliD isolated from the cyanobacterium Synechocystis sp. PCC 6803. We found that the HliD binds chlorophyll-a (Chl-a) and β-carotene and exhibits an energy-dissipative conformation. Using femtosecond spectroscopy, we demonstrated that the energy dissipation is achieved via direct energy transfer from a Chl-a Qy state to the β-carotene S1 state. We did not detect any cation of β-carotene that would accompany Chl-a quenching. These results provide proof of principle that this quenching mechanism operates in the LHC superfamily and also shed light on the photoprotective role of Hlips and the evolution of LHC antennae.

PMID:
25706339
DOI:
10.1038/nchembio.1755
[Indexed for MEDLINE]

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