A Cambialistic Superoxide Dismutase in the Thermophilic Photosynthetic Bacterium Chloroflexus aurantiacus
| Autor: | Robert E. Blankenship, Russell LoBrutto, Fabiyola Selvaraj, Vanessa Lancaster |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
chemistry.chemical_classification
Superoxide Dismutase Thermophile Molecular Sequence Data Chloroflexus aurantiacus Electron Spin Resonance Spectroscopy chemistry.chemical_element Hydrogen Peroxide Manganese Biology biology.organism_classification Enzymes and Proteins Microbiology Anoxygenic photosynthesis Cofactor Chloroflexus Superoxide dismutase Enzyme chemistry Biochemistry biology.protein Amino Acid Sequence Photosynthesis Molecular Biology |
| Zdroj: | Journal of Bacteriology. 186:3408-3414 |
| ISSN: | 1098-5530 0021-9193 |
| Popis: | Superoxide dismutase from the thermophilic anoxygenic photosynthetic bacterium Chloroflexus aurantiacus was cloned, purified, and characterized. This protein is in the manganese- and iron-containing family of superoxide dismutases and is able to use both manganese and iron catalytically. This appears to be the only soluble superoxide dismutase in C. aurantiacus . Iron and manganese cofactors were identified by using electron paramagnetic resonance spectroscopy and were quantified by atomic absorption spectroscopy. By metal enrichment of growth media and by performing metal fidelity studies, the enzyme was found to be most efficient with manganese incorporated, yet up to 30% of the activity was retained with iron. Assimilation of iron or manganese ions into superoxide dismutase was also found to be affected by the growth conditions. This enzyme was also found to be remarkably thermostable and was resistant to H 2 O 2 at concentrations up to 80 mM. Reactive oxygen defense mechanisms have not been previously characterized in the organisms belonging to the phylum Chloroflexi . These systems are of interest in C. aurantiacus since this bacterium lives in a hyperoxic environment and is subject to high UV radiation fluxes. |
| Databáze: | OpenAIRE |
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