State transitions in the cyanobacterium Synechococcus elongatus 7942 involve reversible quenching of the photosystem II core - Archive ouverte HAL
Article Dans Une Revue Biochimica biophysica acta (BBA) - Bioenergetics Année : 2018

State transitions in the cyanobacterium Synechococcus elongatus 7942 involve reversible quenching of the photosystem II core

Reza Ranjbar Choubeh
  • Fonction : Auteur
Emilie Wientjes
  • Fonction : Auteur
Paul C. Struik
Herbert Van Amerongen
  • Fonction : Auteur

Résumé

Cyanobacteria use chlorophyll and phycobiliproteins to harvest light. The resulting excitation energy is delivered to reaction centers (RCs), where photochemistry starts. The relative amounts of excitation energy arriving at the RCs of photosystem I (PSI) and II (PSII) depend on the spectral composition of the light. To balance the excitations in both photosystems, cyanobacteria perform state transitions to equilibrate the excitation energy. They go to state I if PSI is preferentially excited, for example after illumination with blue light (light I), and to state II after illumination with green-orange light (light II) or after dark adaptation. In this study, we performed 77-K time-resolved fluorescence spectroscopy on wild-type Synechococcus elongatus 7942 cells to measure how state transitions affect excitation energy transfer to PSI and PSII in different light conditions and to test the various models that have been proposed in literature. The time-resolved spectra show that the PSII core is quenched in state II and that this is not due to a change in excitation energy transfer from PSII to PSI (spill-over), either direct or indirect via phycobilisomes.

Dates et versions

hal-02177004 , version 1 (08-07-2019)

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Citer

Reza Ranjbar Choubeh, Emilie Wientjes, Paul C. Struik, Diana Kirilovsky, Herbert Van Amerongen. State transitions in the cyanobacterium Synechococcus elongatus 7942 involve reversible quenching of the photosystem II core. Biochimica biophysica acta (BBA) - Bioenergetics, 2018, 1859 (10), pp.1059--1066. ⟨10.1016/j.bbabio.2018.06.008⟩. ⟨hal-02177004⟩
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