6QA9

Isolated complex I class refinement from Ovine respiratory supercomplex I+III2

これはPDB形式変換不可エントリーです。

6QA9 の概要

• エントリーDOI: 10.2210/pdb6qa9/pdb
• 関連するPDBエントリー: 6Q9B 6Q9D 6Q9E
• EMDBエントリー: 4479 4480 4481 4482
• 分子名称: NADH dehydrogenase [ubiquinone] flavoprotein 1, mitochondrial, NADH:ubiquinone oxidoreductase subunit S4, NADH:ubiquinone oxidoreductase subunit A9, ... (53 entities in total)
• 機能のキーワード: complex i, cellular respiration, mitochondria, electron transport
• 由来する生物種: Ovis aries (Sheep); 詳細
• タンパク質・核酸の鎖数: 45
• 化学式量合計: 979744.28

構造登録者

Letts, J.A.,Sazanov, L.A. (登録日: 2018-12-19, 公開日: 2019-08-21, 最終更新日: 2025-12-17)

主引用文献

Letts, J.A.,Fiedorczuk, K.,Degliesposti, G.,Skehel, M.,Sazanov, L.A.
Structures of Respiratory Supercomplex I+III2Reveal Functional and Conformational Crosstalk.
Mol.Cell, 75:1131-1146.e6, 2019

PubMed Abstract: The mitochondrial electron transport chain complexes are organized into supercomplexes (SCs) of defined stoichiometry, which have been proposed to regulate electron flux via substrate channeling. We demonstrate that CoQ trapping in the isolated SC I+III limits complex (C)I turnover, arguing against channeling. The SC structure, resolved at up to 3.8 Å in four distinct states, suggests that CoQ oxidation may be rate limiting because of unequal access of CoQ to the active sites of CIII. CI shows a transition between "closed" and "open" conformations, accompanied by the striking rotation of a key transmembrane helix. Furthermore, the state of CI affects the conformational flexibility within CIII, demonstrating crosstalk between the enzymes. CoQ was identified at only three of the four binding sites in CIII, suggesting that interaction with CI disrupts CIII symmetry in a functionally relevant manner. Together, these observations indicate a more nuanced functional role for the SCs.

PubMed: 31492636
DOI: 10.1016/j.molcel.2019.07.022

実験手法

ELECTRON MICROSCOPY (4.1 Å)