3 years ago

Zeaxanthin and echinenone modify the structure of photosystem I trimer in Synechocystis sp. PCC 6803

Zeaxanthin and echinenone modify the structure of photosystem I trimer in Synechocystis sp. PCC 6803
The function of xanthophylls in the organisation and structure of the photosynthetic complexes is not completely clarified yet. Recently, we observed a reduced level of the photosystem oligomers upon xanthophyll deficiency, although xanthophylls are not considered to be part of the photosynthetic complexes of cyanobacteria. The present study aimed at further investigating the relationship between xanthophylls and photosytem I (PSI) complex in the cyanobacterium Synechocystis sp. PCC 6803. Interestingly, we recorded the presence of echinenone and zeaxanthin in the isolated PSI trimers. These two xanthophyll species are among the most abundant xanthophylls in this cyanobacterial species. Various xanthophyll biosynthesis mutants were used to investigate the specific role of these xanthophylls. Our spectroscopic results revealed specific structural changes manifested in altered pigment-pigment or pigment-protein interactions within PSI complex in the absence of zeaxanthin and echinenone. These structural modifications of the complexes seem to destabilize the PSI trimeric complexes and eventually result in an increased propensity for monomerization. Our results clearly demonstrate that xanthophylls are important for the fine-tuning of the PSI trimer structure. These xanthophylls could be part of the complex or be embedded in the membrane in the vicinity of PSI.

Publisher URL: www.sciencedirect.com/science

DOI: S0005272817300658

You might also like
Never Miss Important Research

Researcher is an app designed by academics, for academics. Create a personalised feed in two minutes.
Choose from over 15,000 academics journals covering ten research areas then let Researcher deliver you papers tailored to your interests each day.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.