Format

Send to

Choose Destination
Plant Physiol. 2016 Jun;171(2):1307-19. doi: 10.1104/pp.16.00479. Epub 2016 Apr 18.

Distinguishing the Roles of Thylakoid Respiratory Terminal Oxidases in the Cyanobacterium Synechocystis sp. PCC 6803.

Author information

1
Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland (M.E., T.H., L.B., Y.A.);Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Cadarache, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Centre National de la Recherche Scientifique, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Aix Marseille Université, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13284 Marseille, France (P.R., G.P.); andDepartment of Biochemistry, University of Cambridge, Cambridge, CB2 1QW United Kingdom (C.J.H., D.J.L.-S.).
2
Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland (M.E., T.H., L.B., Y.A.);Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Cadarache, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Centre National de la Recherche Scientifique, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Aix Marseille Université, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13284 Marseille, France (P.R., G.P.); andDepartment of Biochemistry, University of Cambridge, Cambridge, CB2 1QW United Kingdom (C.J.H., D.J.L.-S.) allahve@utu.fi.

Abstract

Various oxygen-utilizing electron sinks, including the soluble flavodiiron proteins (Flv1/3), and the membrane-localized respiratory terminal oxidases (RTOs), cytochrome c oxidase (Cox) and cytochrome bd quinol oxidase (Cyd), are present in the photosynthetic electron transfer chain of Synechocystis sp. PCC 6803. However, the role of individual RTOs and their relative importance compared with other electron sinks are poorly understood, particularly under light. Via membrane inlet mass spectrometry gas exchange, chlorophyll a fluorescence, P700 analysis, and inhibitor treatment of the wild type and various mutants deficient in RTOs, Flv1/3, and photosystem I, we investigated the contribution of these complexes to the alleviation of excess electrons in the photosynthetic chain. To our knowledge, for the first time, we demonstrated the activity of Cyd in oxygen uptake under light, although it was detected only upon inhibition of electron transfer at the cytochrome b6f site and in ∆flv1/3 under fluctuating light conditions, where linear electron transfer was drastically inhibited due to impaired photosystem I activity. Cox is mostly responsible for dark respiration and competes with P700 for electrons under high light. Only the ∆cox/cyd double mutant, but not single mutants, demonstrated a highly reduced plastoquinone pool in darkness and impaired gross oxygen evolution under light, indicating that thylakoid-based RTOs are able to compensate partially for each other. Thus, both electron sinks contribute to the alleviation of excess electrons under illumination: RTOs continue to function under light, operating on slower time ranges and on a limited scale, whereas Flv1/3 responds rapidly as a light-induced component and has greater capacity.

PMID:
27208274
PMCID:
PMC4902628
DOI:
10.1104/pp.16.00479
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center