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Title: Evolution of an atypical de-epoxidase for photoprotection in the green lineage

Plants, algae and cyanobacteria need to regulate photosynthetic light harvesting in response to the constantly changing light environment. Rapid adjustments are required to maintain fitness because of a trade-off between efficient solar energy conversion and photoprotection. The xanthophyll cycle, in which the carotenoid pigment violaxanthin is reversibly converted into zeaxanthin, is ubiquitous among green algae and plants and is necessary for the regulation of light harvesting, protection from oxidative stress and adaptation to different light conditions. Violaxanthin de-epoxidase (VDE) is the key enzyme responsible for zeaxanthin synthesis from violaxanthin under excess light. Here in this paper, we show that the Chlorophycean VDE (CVDE) gene from the model green alga Chlamydomonas reinhardtii encodes an atypical VDE. This protein is not homologous to the VDE found in plants and is instead related to a lycopene cyclase from photosynthetic bacteria. Unlike the plant-type VDE that is located in the thylakoid lumen, the Chlamydomonas CVDE protein is located on the stromal side of the thylakoid membrane. Phylogenetic analysis suggests that CVDE evolved from an ancient de-epoxidase that was present in the common ancestor of green algae and plants, providing evidence of unexpected diversity in photoprotection in the green lineage.
 [1] ; ORCiD logo [2] ;  [3] ;  [3] ;  [3] ;  [3] ;  [3] ;  [1]
  1. Univ. of California, Berkeley, CA (United States). Howard Hughes Medical Inst., Department of Plant and Microbial Biology; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Molecular Biophysics and Integrated Bioimaging Division
  2. Colorado State Univ., Fort Collins, CO (United States). Dept. of Biology
  3. Univ. of California, Berkeley, CA (United States). Howard Hughes Medical Inst., Department of Plant and Microbial Biology
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Nature Plants
Additional Journal Information:
Journal Volume: 2; Journal Issue: 10; Journal ID: ISSN 2055-0278
Nature Publishing Group
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES; Non-photochemical quenching; Chloroplasts; Light stress
OSTI Identifier: