Journal Article

An Azide-Insensitive Superoxide Dismutase from a Hyperthermophilic Archaeon, Sulfolobus solfataricus

Shigeyuki Yamano and Tadashi Maruyama

in The Journal of Biochemistry

Published on behalf of The Japanese Biochemical Society

Volume 125, issue 1, pages 186-193
Published in print January 1999 | ISSN: 0021-924X
Published online January 1999 | e-ISSN: 1756-2651 | DOI:

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The superoxide dismutase (SOD) gene of Sulfolobus solfataricus, a hyperthermophilic archaeon, was cloned and expressed in Escherichia coli, and its gene product was characterized. When the protein was expressed in E. coli, it formed a homodimer that contained both Mn and Fe. Metal reconstitution experiments of the SOD with Fe or Mn showed that only the Fe-reconstituted SOD was active. Substitution of Tyr88 to Phe did not affect the metal specificity of the enzyme. The Fe-reconstituted SOD was extremely resistant to thermal denaturation; e.g. 96% of the initial activity was retained after heating at 95°C for 2 h. Fe-reconstituted SOD was not inhibited by azide, but fluoride inhibition was observed. This suggests that some steric hindrance in the substrate funnel of the enzyme prevents the access of N3- but allows 02- and F- access to the active site.

Keywords: archaea; azide; hyperthermophile; Sulfolobus solfataricus; superoxide dismutase

Journal Article.  0 words. 

Subjects: Biochemistry