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08:57
Simultaneous Measurement of Superoxide/Hydrogen Peroxide and NADH Production by Flavin-containing Mitochondrial Dehydrogenases
Published on: February 24, 2018
Oxidative protein folding is driven by the electron transport system
1Department of Biology, University of Michigan, Ann Arbor 48109-1048, USA.
Cell
|July 31, 1999
Summary
Disulfide bond formation in cells is linked to energy production. The DsbB enzyme uses quinones to connect protein folding with the electron transport chain, adapting to various oxygen levels.
Area of Science:
- Biochemistry
- Molecular Biology
- Cellular Metabolism
Background:
- Disulfide bond formation is essential for protein folding and function in vivo.
- This process is primarily catalyzed by the DsbA and DsbB proteins.
- The precise mechanisms linking disulfide bond formation to cellular energy metabolism remain incompletely understood.
Purpose of the Study:
- To reconstitute and investigate the in vivo oxidative folding system using purified DsbA and DsbB components.
- To identify the sources of oxidative power driving protein folding.
- To elucidate the direct links between disulfide bond formation and cellular metabolic pathways, specifically the electron transport chain.
Main Methods:
- Reconstitution of the disulfide bond formation system using purified DsbA and DsbB proteins.
- Investigation of electron acceptor roles for DsbB, including quinones.
- Analysis of electron flow pathways through different oxidases (cytochrome bo, cytochrome bd) under varying oxygen conditions.
- Examination of menaquinone's role in electron transfer to alternative acceptors like fumarate under anaerobic conditions.
Main Results:
- Disulfide bond formation is directly coupled to the cellular electron transport chain.
- DsbB utilizes quinones as electron acceptors, enabling flexible electron transport pathways.
- The system adapts to different oxygen availabilities, utilizing specific oxidases (cytochrome bo aerobically, cytochrome bd under partial anaerobiosis) or alternative acceptors (fumarate anaerobically).
- Purified components successfully reconstituted the oxidative folding system.
Conclusions:
- The oxidative folding system, catalyzed by DsbA and DsbB, is tightly integrated with cellular energy metabolism.
- The flexibility of electron transport pathways linked to DsbB highlights the critical importance of disulfide bond formation for cellular function.
- Understanding this coupling provides insights into cellular adaptation and the fundamental processes of protein maturation.
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