Knockdown of the PsbP protein does not prevent assembly of the dimeric PSII core complex but impairs accumulation of photosystem II supercomplexes in tobacco
| Autor: | Akio Murakami, Kentaro Ifuku, Keiji Takabe, Seiko Ishihara, Yumiko Yamamoto, Chikahiro Miyake, Fumihiko Sato, Kunio Ido |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Photosynthetic reaction centre
Chloroplasts Photoinhibition Photosystem II Biophysics Oxygen-evolving complex macromolecular substances Biology Photosystem I Models Biological Thylakoids Biochemistry Light-harvesting complex Tobacco Extrinsic proteins PsbP P700 Nicotiana tabacum Photosystem II Protein Complex food and beverages Cell Biology Plants Genetically Modified Plant Leaves Protein Subunits LHCII–PSII supercomplex Thylakoid RNA Interference Dimerization Gene Deletion |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Bioenergetics. 1787:873-881 |
| ISSN: | 0005-2728 |
| DOI: | 10.1016/j.bbabio.2009.03.004 |
| Popis: | The PsbP protein is an extrinsic subunit of photosystem II (PSII) specifically found in land plants and green algae. Using PsbP-RNAi tobacco, we have investigated effects of PsbP knockdown on protein supercomplex organization within the thylakoid membranes and photosynthetic properties of PSII. In PsbP-RNAi leaves, PSII dimers binding the extrinsic PsbO protein could be formed, while the light-harvesting complex II (LHCII)–PSII supercomplexes were severely decreased. Furthermore, LHCII and major PSII subunits were significantly dephosphorylated. Electron microscopic analysis showed that thylakoid grana stacking in PsbP-RNAi chloroplast was largely disordered and appeared similar to the stromally-exposed or marginal regions of wild-type thylakoids. Knockdown of PsbP modified both the donor and acceptor sides of PSII; In addition to the lower water-splitting activity, the primary quinone QA in PSII was significantly reduced even when the photosystem I reaction center (P700) was noticeably oxidized, and thermoluminescence studies suggested the stabilization of the charged pair, S2/QA−. These data indicate that assembly and/or maintenance of the functional MnCa cluster is perturbed in absence of PsbP, which impairs accumulation of final active forms of PSII supercomplexes. |
| Databáze: | OpenAIRE |
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