Scavenging of superoxide by a membrane-bound superoxide oxidase.
- Lundgren CAK Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.
- Sjöstrand D Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden. dan.sjostrand@dbb.su.se.
- Biner O Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland.
- Bennett M Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.
- Rudling A Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.
- Johansson AL Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.
- Brzezinski P Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.
- Carlsson J Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.
- von Ballmoos C Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland. christoph.vonballmoos@dcb.unibe.ch.
- Högbom M Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden. hogbom@dbb.su.se.
- 2018-06-20
Published in:
- Nature chemical biology. - 2018
Cell Membrane
Cytochromes b
Escherichia coli
Free Radical Scavengers
Models, Molecular
Protein Conformation
Superoxides
English
Superoxide is a reactive oxygen species produced during aerobic metabolism in mitochondria and prokaryotes. It causes damage to lipids, proteins and DNA and is implicated in cancer, cardiovascular disease, neurodegenerative disorders and aging. As protection, cells express soluble superoxide dismutases, disproportionating superoxide to oxygen and hydrogen peroxide. Here, we describe a membrane-bound enzyme that directly oxidizes superoxide and funnels the sequestered electrons to ubiquinone in a diffusion-limited reaction. Experiments in proteoliposomes and inverted membranes show that the protein is capable of efficiently quenching superoxide generated at the membrane in vitro. The 2.0 Å crystal structure shows an integral membrane di-heme cytochrome b poised for electron transfer from the P-side and proton uptake from the N-side. This suggests that the reaction is electrogenic and contributes to the membrane potential while also conserving energy by reducing the quinone pool. Based on this enzymatic activity, we propose that the enzyme family be denoted superoxide oxidase (SOO).
- Language
-
- English
- Open access status
- green
- Identifiers
-
- DOI 10.1038/s41589-018-0072-x
- PMID 29915379
- Persistent URL
- https://sonar.ch/global/documents/156027
Statistics
Document views: 67
File downloads:
- Full-text: 0