Low light-regulated intramolecular disulfide fine-tunes the role of PTOX in Arabidopsis
| Autor: | Ido Rog, Amit Kumar Chaturvedi, Vivekanand Tiwari, Avihai Danon |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Oxidase test
biology Adaptation Ocular Arabidopsis Proteins Arabidopsis Plastoquinone Cell Biology Plant Science biology.organism_classification Plastid terminal oxidase Redox Chloroplast Light intensity chemistry.chemical_compound chemistry Genetics Biophysics Arabidopsis thaliana Disulfides Plastids Photosynthesis Oxidoreductases Oxidation-Reduction |
| Zdroj: | The Plant journal : for cell and molecular biologyREFERENCES. 109(3) |
| ISSN: | 1365-313X |
| Popis: | Disulfide-based regulation links the activity of numerous chloroplast proteins with photosynthesis-derived redox signals. The plastid terminal oxidase (PTOX) is a thylakoid-bound plastoquinol oxidase that has been implicated in multiple roles in the light and in the dark, which could require different levels of PTOX activity. Here we show that Arabidopsis PTOX contains a conserved C-terminus domain (CTD) with cysteines that evolved progressively following the colonization of the land by plants. Furthermore, the CTD contains a regulatory disulfide that is in the oxidized state in the dark and is rapidly reduced, within 5 min, in low light intensity (1-5 µE m-2 sec-1 ). The reduced PTOX form in the light was reoxidized within 15 min after transition to the dark. Mutation of the cysteines in the CTD prevented the formation of the oxidized form. This resulted in higher levels of reduced plastoquinone when measured at transition to the onset of low light. This is consistent with the reduced state of PTOX exhibiting diminished PTOX oxidase activity under conditions of limiting PQH2 substrate. Our findings suggest that AtPTOX-CTD evolved to provide light-dependent regulation of PTOX activity for the adaptation of plants to terrestrial conditions. |
| Databáze: | OpenAIRE |
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