Pinto, Ana F. and Romao, Celia V. and Pinto, Liliana C. and Huber, Harald and Saraiva, Ligia M. and Todorovic, Smilja and Cabelli, Diane and Teixeira, Miguel (2015) Superoxide reduction by a superoxide reductase lacking the highly conserved lysine residue. JOURNAL OF BIOLOGICAL INORGANIC CHEMISTRY, 20 (1). pp. 155-164. ISSN 0949-8257, 1432-1327
Full text not available from this repository. (Request a copy)Abstract
Superoxide reductases (SORs) are the most recently identified superoxide detoxification systems, being found in microorganisms from the three domains of life. These enzymes are characterized by a catalytic mononuclear iron site, with one cysteine and four histidine ligands of the ferrous active form. A lysine residue in the -EKHVP- motif, located close to the active site, has been considered to be essential for the enzyme function, by contributing to the positive surface patch that attracts the superoxide anion and by controlling the chemistry of the catalytic mechanism through a hydrogen bond network. However, we show here that this residue is substituted by non-equivalent amino acids in several putative SORs from Archaea and unicellular Eukarya. In this work, we focus on mechanistic and spectroscopic studies of one of these less common enzymes, the SOR from the hyperthermophilic Crenarchaeon Ignicoccus hospitalis. We employ pulse radiolysis fast kinetics and spectroscopic approaches to study the wild-type enzyme (-E23T24HVP-), and two mutants, T24K and E23A, the later mimicking enzymes lacking both the lysine and glutamate (a ferric ion ligand) of the motif. The efficiency of the wild-type protein and mutants in reducing superoxide is comparable to other SORs, revealing the robustness of these enzymes to single mutations.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | IRON ACTIVE-SITE; DESULFOARCULUS-BAARSII; ARCHAEOGLOBUS-FULGIDUS; PYROCOCCUS-FURIOSUS; TREPONEMA-PALLIDUM; DESULFOVIBRIO-VULGARIS; PULSE-RADIOLYSIS; MECHANISM; NEELAREDOXIN; PEROXIDE; Superoxide; Oxidative stress; Superoxide reductase; Ignicoccus |
| Subjects: | 500 Science > 570 Life sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Biochemie, Genetik und Mikrobiologie > Lehrstuhl für Mikrobiologie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 02 Aug 2019 11:49 |
| Last Modified: | 02 Aug 2019 11:49 |
| URI: | https://pred.uni-regensburg.de/id/eprint/6348 |
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