7TIH

Structure of oxidized bovine cytochrome c oxidase with reduced metal centers induced by synchrotron X-ray exposure

7TIH の概要

• エントリーDOI: 10.2210/pdb7tih/pdb
• 関連するPDBエントリー: 7THU 7TIE
• 分子名称: Cytochrome c oxidase subunit 1, Cytochrome c oxidase subunit 7A1, mitochondrial, Cytochrome c oxidase subunit 7B, mitochondrial, ... (30 entities in total)
• 機能のキーワード: bioenergetics, proton translocation, oxidoreductase, membrane protein
• 由来する生物種: Bos taurus (cattle); 詳細
• タンパク質・核酸の鎖数: 26
• 化学式量合計: 450080.25

構造登録者

Ishigami, I.,Rousseau, D.L.,Yeh, S.-R.,Russi, S.,Cohen, A. (登録日: 2022-01-13, 公開日: 2022-03-30, 最終更新日: 2023-10-18)

主引用文献

Ishigami, I.,Russi, S.,Cohen, A.,Yeh, S.R.,Rousseau, D.L.
Temperature-dependent structural transition following X-ray-induced metal center reduction in oxidized cytochrome c oxidase.
J.Biol.Chem., 298:101799-101799, 2022

PubMed Abstract: Cytochrome c oxidase (CcO) is the terminal enzyme in the electron transfer chain in the inner membrane of mitochondria. It contains four metal redox centers, two of which, Cu and heme a, form the binuclear center (BNC), where dioxygen is reduced to water. Crystal structures of CcO in various forms have been reported, from which ligand-binding states of the BNC and conformations of the protein matrix surrounding it have been deduced to elucidate the mechanism by which the oxygen reduction chemistry is coupled to proton translocation. However, metal centers in proteins can be susceptible to X-ray-induced radiation damage, raising questions about the reliability of conclusions drawn from these studies. Here, we used microspectroscopy-coupled X-ray crystallography to interrogate how the structural integrity of bovine CcO in the fully oxidized state (O) is modulated by synchrotron radiation. Spectroscopic data showed that, upon X-ray exposure, O was converted to a hybrid O∗ state where all the four metal centers were reduced, but the protein matrix was trapped in the genuine O conformation and the ligands in the BNC remained intact. Annealing the O∗ crystal above the glass transition temperature induced relaxation of the O∗ structure to a new R∗ structure, wherein the protein matrix converted to the fully reduced R conformation with the exception of helix X, which partly remained in the O conformation because of incomplete dissociation of the ligands from the BNC. We conclude from these data that reevaluation of reported CcO structures obtained with synchrotron light sources is merited.

PubMed: 35257742
DOI: 10.1016/j.jbc.2022.101799

実験手法

X-RAY DIFFRACTION (2.35 Å)