6LOE

Cryo-EM structure of the dithionite-reduced photosynthetic alternative complex III from Roseiflexus castenholzii

6LOE の概要

• エントリーDOI: 10.2210/pdb6loe/pdb
• 関連するPDBエントリー: 6LOD
• EMDBエントリー: 0936 0937
• 分子名称: MULTIHEME_CYTC domain-containing protein, [(2S)-2-octadecanoyloxypropyl] octadecanoate, Fe-S-cluster-containing hydrogenase components 1-like protein, ... (10 entities in total)
• 機能のキーワード: quinol:electron acceptor oxidoreductase, photosynthesis
• 由来する生物種: Roseiflexus castenholzii (strain DSM 13941 / HLO8); 詳細
• タンパク質・核酸の鎖数: 6
• 化学式量合計: 274679.54

構造登録者

Shi, Y.,Xin, Y.Y.,Wang, C.,Blankenship, R.E.,Sun, F.,Xu, X.L. (登録日: 2020-01-05, 公開日: 2020-11-04)

主引用文献

Shi, Y.,Xin, Y.,Wang, C.,Blankenship, R.E.,Sun, F.,Xu, X.
Cryo-EM structures of the air-oxidized and dithionite-reduced photosynthetic alternative complex III from Roseiflexus castenholzii .
Sci Adv, 6:eaba2739-eaba2739, 2020

PubMed Abstract: 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.

PubMed: 32832681
DOI: 10.1126/sciadv.aba2739

実験手法

ELECTRON MICROSCOPY (3.5 Å)