The PsbZ subunit of Photosystem II in Synechocystis sp. PCC 6803 modulates electron flow through the photosynthetic electron transfer chain
| Autor: | Cleo L. Bishop, Elena Baena-González, Simin Ulas, Pirkko Mäenpää, Saul Purton, Jonathan H. A. Nugent, Eva-Mari Aro |
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| Rok vydání: | 2007 |
| Předmět: |
Photosystem II
Electrons Photophosphorylation macromolecular substances Plant Science Biology Photochemistry Photosynthesis Photosystem I Thylakoids Biochemistry Electron Transport Electron transfer Bacterial Proteins P700 Non-photochemical quenching Electron Spin Resonance Spectroscopy Synechocystis Temperature Photosystem II Protein Complex food and beverages Intracellular Membranes Cell Biology General Medicine Darkness Electron transport chain Oxygen Protein Subunits Phenotype Spectrometry Fluorescence Mutation Biophysics Oxidation-Reduction |
| Zdroj: | Photosynthesis Research. 93:139-147 |
| ISSN: | 1573-5079 0166-8595 |
| DOI: | 10.1007/s11120-007-9182-0 |
| Popis: | The psbZ gene of Synechocystis sp. PCC 6803 encodes the approximately 6.6 kDa photosystem II (PSII) subunit. We here report biophysical, biochemical and in vivo characterization of Synechocystis sp. PCC 6803 mutants lacking psbZ. We show that these mutants are able to perform wild-type levels of light-harvesting, energy transfer, PSII oxygen evolution, state transitions and non-photochemical quenching (NPQ) under standard growth conditions. The mutants grow photoautotrophically; however, their growth rate is clearly retarded under low-light conditions and they are not capable of photomixotrophic growth. Further differences exist in the electron transfer properties between the mutants and wild type. In the absence of PsbZ, electron flow potentially increased through photosystem I (PSI) without a change in the maximum electron transfer capacity of PSII. Further, rereduction of P700(+) is much faster, suggesting faster cyclic electron flow around PSI. This implies a role for PsbZ in the regulation of electron transfer, with implication for photoprotection. |
| Databáze: | OpenAIRE |
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