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-Structure paper
タイトル | Cryo-EM structures of the air-oxidized and dithionite-reduced photosynthetic alternative complex III from . |
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ジャーナル・号・ページ | Sci Adv, Vol. 6, Issue 31, Page eaba2739, Year 2020 |
掲載日 | 2020年7月29日 |
著者 | Yang Shi / Yueyong Xin / Chao Wang / Robert E Blankenship / Fei Sun / Xiaoling Xu / |
PubMed 要旨 | Alternative complex III (ACIII) is a multisubunit quinol:electron acceptor oxidoreductase that couples quinol oxidation with transmembrane proton translocation in both the respiratory and ...Alternative complex III (ACIII) is a multisubunit quinol:electron acceptor oxidoreductase that couples quinol oxidation with transmembrane proton translocation in both the respiratory and photosynthetic electron transport chains of bacteria. The coupling mechanism, however, is poorly understood. Here, we report the cryo-EM structures of air-oxidized and dithionite-reduced ACIII from the photosynthetic bacterium at 3.3- and 3.5-Å resolution, respectively. We identified a menaquinol binding pocket and an electron transfer wire comprising six hemes and four iron-sulfur clusters that is capable of transferring electrons to periplasmic acceptors. We detected a proton translocation passage in which three strictly conserved, mid-passage residues are likely essential for coupling the redox-driven proton translocation across the membrane. These results allow us to propose a previously unrecognized coupling mechanism that links the respiratory and photosynthetic functions of ACIII. This study provides a structural basis for further investigation of the energy transformation mechanisms in bacterial photosynthesis and respiration. |
リンク | Sci Adv / PubMed:32832681 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 3.2 - 3.5 Å |
構造データ | |
化合物 | ChemComp-HEC: ChemComp-EL6: ChemComp-SF4: ChemComp-F3S: |
由来 |
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キーワード | PHOTOSYNTHESIS / quinol:electron acceptor oxidoreductase |