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若林 憲一 所属 京都産業大学 生命科学部 産業生命科学科 職種 教授 |
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| 言語種別 | 英語 |
| 発行・発表の年月 | 2023/02 |
| 形態種別 | 研究論文 |
| 査読 | 査読あり |
| 標題 | Two specific domains of the γ subunit of chloroplast F o F 1 provide redox regulation of the ATP synthesis through conformational changes |
| 執筆形態 | その他 |
| 掲載誌名 | Proceedings of the National Academy of Sciences |
| 出版社・発行元 | Proceedings of the National Academy of Sciences |
| 巻・号・頁 | 120(6) |
| 担当区分 | 責任著者 |
| 著者・共著者 | Kentaro Akiyama,Shin-Ichiro Ozawa,Yuichiro Takahashi,Keisuke Yoshida,Toshiharu Suzuki,Kumiko Kondo,Ken-ichi Wakabayashi,Toru Hisabori |
| 概要 | <jats:p>
Chloroplast F <jats:sub>o</jats:sub> F <jats:sub>1</jats:sub> -ATP synthase (CF <jats:sub>o</jats:sub> CF <jats:sub>1</jats:sub> ) converts proton motive force into chemical energy during photosynthesis. Although many studies have been done to elucidate the catalytic reaction and its regulatory mechanisms, biochemical analyses using the CF <jats:sub>o</jats:sub> CF <jats:sub>1</jats:sub> complex have been limited because of various technical barriers, such as the difficulty in generating mutants and a low purification efficiency from spinach chloroplasts. By taking advantage of the powerful genetics available in the unicellular green alga <jats:italic>Chlamydomonas reinhardtii</jats:italic> , we analyzed the ATP synthesis reaction and its regulation in CF <jats:sub>o</jats:sub> CF <jats:sub>1</jats:sub> . The domains in the γ subunit involved in the redox regulation of CF <jats:sub>o</jats:sub> CF <jats:sub>1</jats:sub> were mutated based on the reported structure. An in vivo analysis of strains harboring these mutations revealed the structural determinants of the redox response during the light/dark transitions. In addition, we established a half day purification method for the entire CF <jats:sub>o</jats:sub> CF <jats:sub>1</jats:sub> complex from <jats:italic>C. reinhardtii</jats:italic> and subsequently examined ATP synthesis activity by the acid–base transition method. We found that truncation of the β-hairpin domain resulted in a loss of redox regulation of ATP synthesis (i.e., constitutively active state) despite retaining redox-sensitive Cys residues. In contrast, truncation of the redox loop domain containing the Cys residues resulted in a marked decrease in the activity. Based on this mutation analysis, we propose a model of redox regulation of the ATP synthesis reaction by the cooperative function of the β-hairpin and the redox loop domains specific to CF <jats:sub>o</jats:sub> CF <jats:sub>1</jats:sub> . </jats:p> |
| DOI | 10.1073/pnas.2218187120 |
| ISSN | 0027-8424 |
| Put Code(ORCID) | 127697436 |