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Initial characterization of an iron superoxide dismutase from Thermobifida fusca.

Anne Grethe HamreRim Al-SadawiKirsti Merete JohannesenBastien BisarroÅsmund Røhr KjendsethHanna-Kirsti S LeirosMorten Sørlie
Published in: Journal of biological inorganic chemistry : JBIC : a publication of the Society of Biological Inorganic Chemistry (2023)
Superoxide dismutases (SODs) are enzymes that catalyze the dismutation of the superoxide radical anion into O 2 and H 2 O 2 in a two-step reaction. They are ubiquitous to all forms of life and four different types of metal centers are detected, dividing this class of enzymes into Cu-/Zn-, Ni-, Mn-, and Fe-SODs. In this study, a superoxide dismutase from the thermophilic bacteria Thermobifida fusca (TfSOD) was cloned and expressed before the recombinant enzyme was characterized. The enzyme was found to be active for superoxide dismutation measured by inhibition of cytochrome c oxidation and the inhibition of the autoxidation of pyrogallol. Its pH-optimum was determined to be 7.5, while it has a broad temperature optimum ranging from 20 to 90 °C. Combined with the T m that was found to be 78.5 ± 0.5 °C at pH 8.0, TfSOD can be defined as a thermostable enzyme. Moreover, the crystal structure of TfSOD was determined and refined to 1.25 Å resolution. With electron paramagnetic resonance spectroscopy, it was confirmed that iron is the metal co-factor of TfSOD. The cell potential (E m ) for the TfSOD-Fe 3+ /TfSOD-Fe 2+ redox couple was determined to be 287 mV.
Keyphrases
  • hydrogen peroxide
  • metal organic framework
  • nitric oxide
  • aqueous solution
  • single cell
  • stem cells
  • high resolution
  • heavy metals
  • cell therapy
  • mesenchymal stem cells
  • climate change
  • energy transfer
  • room temperature