5oc0
From Proteopedia
Structure of E. coli superoxide oxidase
Structural highlights
FunctionC561_ECOLI B-type di-heme cytochrome with a major alpha-absorption peak at 561 nm and a minor peak at 555 nm. Publication Abstract from PubMedSuperoxide 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 A 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). Scavenging of superoxide by a membrane-bound superoxide oxidase.,Lundgren CAK, Sjostrand D, Biner O, Bennett M, Rudling A, Johansson AL, Brzezinski P, Carlsson J, von Ballmoos C, Hogbom M Nat Chem Biol. 2018 Jun 18. pii: 10.1038/s41589-018-0072-x. doi:, 10.1038/s41589-018-0072-x. PMID:29915379[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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