Abstract
In photosynthetic organisms, carotenoids (carotenes and xanthophylls) are important for light harvesting, photoprotection and structural stability of a variety of pigment-protein complexes. Here, we investigated the consequences of altered carotenoid composition for the functional organization of photosynthetic complexes in wild-type and various mutant strains of the cyanobacterium Synechocystis sp. PCC 6803. Although it is generally accepted that xanthophylls do not play a role in cyanobacterial photosynthesis in low-light conditions, we have found that the absence of xanthophylls leads to reduced oligomerization of photosystems I and II. This is remarkable because these complexes do not bind xanthophylls. Oligomerization is even more disturbed in crtH mutant cells, which show limited carotenoid synthesis; in these cells also the phycobilisomes are distorted despite the fact that these extramembranous light-harvesting complexes do not contain carotenoids. The number of phycocyanin rods connected to the phycobilisome core is strongly reduced leading to high amounts of unattached phycocyanin units. In the absence of carotenoids the overall organization of the thylakoid membranes is disturbed: Photosystem II is not formed, photosystem I hardly oligomerizes and the assembly of phycobilisomes remains incomplete. These data underline the importance of carotenoids in the structural and functional organization of the cyanobacterial photosynthetic machinery.
Original language | English |
---|---|
Pages (from-to) | 1153-1165 |
Number of pages | 13 |
Journal | Biochimica et Biophysica Acta - Bioenergetics |
Volume | 1847 |
Issue number | 10 |
DOIs | |
Publication status | Published - 29 Jun 2015 |
Bibliographical note
Funding Information:This work was supported by the Sandwich PhD program of Wageningen University (to T.T.), by the HARVEST Marie Curie Research Training Network ( PITN-GA-2009-238017 ) (to V.C.), grant OTKA K108411 and K112688 from the Hungarian Scientific Research Fund (to T.T. and GG, respectively), Social Renewal Operational Programs ( TAMOP-4.2.2/B-10/1-2010-0012 to T.T., TAMOP-4.2.2.A-11/1/KONV-2012-0047 to L.K.), A*STAR Singapore ( NIH-A*STAR TET_10-1-2011-0279 , to G.G.), P501/12/G055 of the Grant Agency of the Czech republic (to J. Knoppová and J. K.), bilateral project of Academy of Science of the Czech Republic and Hungary ( HU/2013/06 to Z.G. and J.K.) and the National Program of Sustainability I , ID: LO1416 (to J. Knoppová and J.K).
Publisher Copyright:
© 2015 Elsevier B.V. All rights reserved.
Funding
This work was supported by the Sandwich PhD program of Wageningen University (to T.T.), by the HARVEST Marie Curie Research Training Network ( PITN-GA-2009-238017 ) (to V.C.), grant OTKA K108411 and K112688 from the Hungarian Scientific Research Fund (to T.T. and GG, respectively), Social Renewal Operational Programs ( TAMOP-4.2.2/B-10/1-2010-0012 to T.T., TAMOP-4.2.2.A-11/1/KONV-2012-0047 to L.K.), A*STAR Singapore ( NIH-A*STAR TET_10-1-2011-0279 , to G.G.), P501/12/G055 of the Grant Agency of the Czech republic (to J. Knoppová and J. K.), bilateral project of Academy of Science of the Czech Republic and Hungary ( HU/2013/06 to Z.G. and J.K.) and the National Program of Sustainability I , ID: LO1416 (to J. Knoppová and J.K).
Keywords
- Carotenoid deficiency
- Cyanobacterial photosynthesis
- Photosynthetic complexes
- Phycobilisome
- Time-resolved fluorescence