PsbN Is Required for Assembly of the Photosystem II Reaction Center in Nicotiana tabacum
| Autor: | Hanumakumar Bogireddi, Wolfgang P. Schröder, Nikolay Manavski, Reinhold G. Herrmann, Jörg Meurer, Gerhard Wanner, Pavan Umate, Magdalena Plöchinger, Salar Torabi, Laura Kleinknecht |
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| Rok vydání: | 2014 |
| Předmět: |
Photosynthetic reaction centre
Photoinhibition Light Transcription Genetic Photosystem II Protein subunit Nicotiana tabacum Mutant macromolecular substances Plant Science Genes Plant Gene Expression Regulation Plant Operon Tobacco Allotopic expression Research Articles Plant Proteins Genetics biology Gene Expression Profiling Photosystem II Protein Complex food and beverages Cell Biology biology.organism_classification Chloroplast Mutation Biophysics |
| Zdroj: | The Plant Cell. 26:1183-1199 |
| ISSN: | 1532-298X 1040-4651 |
| Popis: | ORCID ID: 0000-0003-2973-9514 (J.M.) The chloroplast-encoded low molecular weight protein PsbN is annotated as a photosystem II (PSII) subunit. To elucidate the localization and function of PsbN, encoded on the opposite strand to the psbB gene cluster, we raised antibodies and inserted a resistance cassette into PsbN in both directions. Both homoplastomic tobacco (Nicotiana tabacum) mutants ΔpsbN-F and ΔpsbN-R show essentially the same PSII deficiencies. The mutants are extremely light sensitive and failed to recover from photoinhibition. Although synthesis of PSII proteins was not altered significantly, both mutants accumulated only ;25% of PSII proteins compared with the wild type. Assembly of PSII precomplexes occurred at normal rates, but heterodimeric PSII reaction centers (RCs) and higher order PSII assemblies were not formed efficiently in the mutants. The ΔpsbN-R mutant was complemented by allotopic expression of the PsbN gene fused to the sequence of a chloroplast transit peptide in the nuclear genome. PsbN represents a bitopic trans-membrane peptide localized in stroma lamellae with its highly conserved C terminus exposed to the stroma. Significant amounts of PsbN were already present in dark-grown seedling. Our data prove that PsbN is not a constituent subunit of PSII but is required for repair from photoinhibition and efficient assembly of the PSII RC. |
| Databáze: | OpenAIRE |
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