7P91

TmHydABC- T. maritima bifurcating hydrogenase with bridge domain closed

Summary for 7P91

• Entry DOI: 10.2210/pdb7p91/pdb
• Related: 7P5H 7P8N
• EMDB information: 13257
• Descriptor: Fe-hydrogenase, subunit alpha, Fe-hydrogenase, subunit beta, Fe-hydrogenase, subunit gamma, ... (8 entities in total)
• Functional Keywords: hydrogenase, bifurcation, confurcaction, cryoem, electron transfer, oxidoreductase, complex
• Biological source: Thermotoga maritima (strain ATCC 43589 / DSM 3109 / JCM 10099 / NBRC 100826 / MSB8); More
• Total number of polymer chains: 6
• Total formula weight: 330617.86

Authors

Furlan, C.,Chongdar, N.,Gupta, P.,Lubitz, W.,Ogata, H.,Blaza, J.N.,Birrell, J.A. (deposition date: 2021-07-23, release date: 2022-09-14, Last modification date: 2024-07-17)

Primary citation

Furlan, C.,Chongdar, N.,Gupta, P.,Lubitz, W.,Ogata, H.,Blaza, J.N.,Birrell, J.A.
Structural insight on the mechanism of an electron-bifurcating [FeFe] hydrogenase.
Elife, 11:-, 2022

PubMed Abstract: Electron bifurcation is a fundamental energy conservation mechanism in nature in which two electrons from an intermediate-potential electron donor are split so that one is sent along a high-potential pathway to a high-potential acceptor and the other is sent along a low-potential pathway to a low-potential acceptor. This process allows endergonic reactions to be driven by exergonic ones and is an alternative, less recognized, mechanism of energy coupling to the well-known chemiosmotic principle. The electron-bifurcating [FeFe] hydrogenase from (HydABC) requires both NADH and ferredoxin to reduce protons generating hydrogen. The mechanism of electron bifurcation in HydABC remains enigmatic in spite of intense research efforts over the last few years. Structural information may provide the basis for a better understanding of spectroscopic and functional information. Here, we present a 2.3 Å electron cryo-microscopy structure of HydABC. The structure shows a heterododecamer composed of two independent 'halves' each made of two strongly interacting HydABC heterotrimers connected via a [4Fe-4S] cluster. A central electron transfer pathway connects the active sites for NADH oxidation and for proton reduction. We identified two conformations of a flexible iron-sulfur cluster domain: a 'closed bridge' and an 'open bridge' conformation, where a Zn site may act as a 'hinge' allowing domain movement. Based on these structural revelations, we propose a possible mechanism of electron bifurcation in HydABC where the flavin mononucleotide serves a dual role as both the electron bifurcation center and as the NAD reduction/NADH oxidation site.

PubMed: 36018003
DOI: 10.7554/eLife.79361

Experimental method

ELECTRON MICROSCOPY (2.8 Å)