Iron incorporation into MnSOD A (bacterial Mn-dependent superoxide dismutase) leads to the formation of a peroxidase/catalase implicated in oxidative damage to bacteria
| Autor: | Lori L. Edwards, Ronald P. Mason, Robert M. Petrovich, Douglas Ganini |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Antioxidant
medicine.medical_treatment Iron Biophysics chemistry.chemical_element Biochemistry Oxygen Article Superoxide dismutase chemistry.chemical_compound Bacterial Proteins medicine Molecular Biology Peroxidase chemistry.chemical_classification biology Bacteria Chemistry Superoxide Superoxide Dismutase biology.organism_classification Catalase Enzyme biology.protein |
| Zdroj: | Biochimica et biophysica acta. 1850(9) |
| ISSN: | 0006-3002 |
| Popis: | Background Mn/Fe-superoxide dismutase (SOD) is a family of enzymes essential for organisms to be able to cope with oxygen. These enzymes bound to their classical metals catalyze the dismutation of the free radical superoxide anion (O 2 − ) to H 2 O 2 and molecular oxygen. E. coli has the manganese-dependent SOD A and the iron-dependent SOD B. Methods Strains of E. coli overexpressing SOD A or SOD B were grown in media with different metal compositions. SODs were purified and their metal content and SOD activity were determined. Those proteins were incubated with H 2 O 2 and assayed for oxidation of Amplex red or o-phenylenediamine, consumption of H 2 O 2 , release of iron and protein radical formation. Cell survival was determined in bacteria with MnSOD A or FeSOD A after being challenged with H 2 O 2 . Results We show for the first time that the bacterial manganese-dependent SOD A when bound to iron (FeSOD A) has peroxidase activity. The in vivo formation of the peroxidase FeSOD A was increased when media had higher levels of iron because of a decreased manganese metal incorporation. In comparison to bacteria with MnSOD A, cells with FeSOD A had a higher loss of viability when exposed to H 2 O 2 . General Significance The biological occurrence of this fundamental antioxidant enzyme in an alternative iron-dependent state represents an important source of free radical formation. |
| Databáze: | OpenAIRE |
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