8BEW

Cryo-EM structure of the electron bifurcating Fe-Fe hydrogenase HydABC complex from Thermoanaerobacter kivui in the oxidised state

8BEW の概要

• エントリーDOI: 10.2210/pdb8bew/pdb
• EMDBエントリー: 16011
• 分子名称: Electron bifurcating hydrogenase subunit HydA1, Electron bifurcating hydrogenase subunit HydB, Electron bifurcating hydrogenase subunit HydC, ... (7 entities in total)
• 機能のキーワード: bioenergetics, acetogenesis, flavin-based electron bifurcation, [fefe]-hydrogenase, molecular simulations, electron transport
• 由来する生物種: Thermoanaerobacter kivui; 詳細
• タンパク質・核酸の鎖数: 6
• 化学式量合計: 308610.29

構造登録者

Kumar, A.,Schuller, J.M. (登録日: 2022-10-22, 公開日: 2023-02-15, 最終更新日: 2025-12-17)

主引用文献

Katsyv, A.,Kumar, A.,Saura, P.,Poverlein, M.C.,Freibert, S.A.,T Stripp, S.,Jain, S.,Gamiz-Hernandez, A.P.,Kaila, V.R.I.,Muller, V.,Schuller, J.M.
Molecular Basis of the Electron Bifurcation Mechanism in the [FeFe]-Hydrogenase Complex HydABC.
J.Am.Chem.Soc., 145:5696-5709, 2023

PubMed Abstract: Electron bifurcation is a fundamental energy coupling mechanism widespread in microorganisms that thrive under anoxic conditions. These organisms employ hydrogen to reduce CO, but the molecular mechanisms have remained enigmatic. The key enzyme responsible for powering these thermodynamically challenging reactions is the electron-bifurcating [FeFe]-hydrogenase HydABC that reduces low-potential ferredoxins (Fd) by oxidizing hydrogen gas (H). By combining single-particle cryo-electron microscopy (cryoEM) under catalytic turnover conditions with site-directed mutagenesis experiments, functional studies, infrared spectroscopy, and molecular simulations, we show that HydABC from the acetogenic bacteria and employ a single flavin mononucleotide (FMN) cofactor to establish electron transfer pathways to the NAD(P) and Fd reduction sites by a mechanism that is fundamentally different from classical flavin-based electron bifurcation enzymes. By modulation of the NAD(P) binding affinity via reduction of a nearby iron-sulfur cluster, HydABC switches between the exergonic NAD(P) reduction and endergonic Fd reduction modes. Our combined findings suggest that the conformational dynamics establish a redox-driven kinetic gate that prevents the backflow of the electrons from the Fd reduction branch toward the FMN site, providing a basis for understanding general mechanistic principles of electron-bifurcating hydrogenases.

PubMed: 36811855
DOI: 10.1021/jacs.2c11683

実験手法

ELECTRON MICROSCOPY (3.49 Å)