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モトハシ タケシ
MOTOHASHI TAKESHI
本橋 健 所属 京都産業大学 生命科学部 先端生命科学科 職種 教授 |
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| 発行・発表の年月 | 2023/08 |
| 形態種別 | 研究論文 |
| 査読 | 査読あり |
| 標題 | Two disulfide-reducing pathways are required for the maturation of plastid c-type cytochromes in Chlamydomonas reinhardtii |
| 執筆形態 | その他 |
| 掲載誌名 | GENETICS |
| 出版社・発行元 | Oxford University Press (OUP) |
| 著者・共著者 | Ankita Das,Nitya Subrahmanian,Stéphane T Gabilly,Ekaterina P Andrianova,Igor B Zhulin,Ken Motohashi,Patrice Paul Hamel |
| 概要 | Abstract
In plastids, conversion of light energy into ATP relies on cytochrome f, a key electron carrier with a heme covalently attached to a CXXCH motif. Covalent heme attachment requires reduction of the disulfide-bonded CXXCH by CCS5 and CCS4. CCS5 receives electrons from the oxidoreductase CCDA, while CCS4 is a protein of unknown function. In Chlamydomonas reinhardtii, loss of CCS4 or CCS5 yields a partial cytochrome f assembly defect. Here, we report that the ccs4ccs5 double mutant displays a synthetic photosynthetic defect characterized by a complete loss of holocytochrome f assembly. This defect is chemically corrected by reducing agents, confirming the placement of CCS4 and CCS5 in a reducing pathway. CCS4-like proteins occur in the green lineage, and we show that HCF153, a distant ortholog from Arabidopsis thaliana, can substitute for Chlamydomonas CCS4. Dominant suppressor mutations mapping to the CCS4 gene were identified in photosynthetic revertants of the ccs4ccs5 mutants. The suppressor mutations yield changes in the stroma-facing domain of CCS4 that restore holocytochrome f assembly above the residual levels detected in ccs5. Because the CCDA protein accumulation is decreased specifically in the ccs4 mutant, we hypothesize the suppressor mutations enhance the supply of reducing power through CCDA in the absence of CCS5. We discuss the operation of a CCS5-dependent and a CCS5-independent pathway controlling the redox status of the heme-binding cysteines of apocytochrome f. |
| DOI | 10.1093/genetics/iyad155 |
| ISSN | /1943-2631 |
| PermalinkURL | https://academic.oup.com/genetics/advance-article-pdf/doi/10.1093/genetics/iyad155/51516274/iyad155.pdf |