title: Understanding how the thiolate sulfur contributes to the function of the non-heme iron enzyme superoxide reductase.
abstract: Toxic superoxide radicals, generated via adventitious reduction of dioxygen, have been implicated in a number of disease states. The cysteinate-ligated non-heme iron enzyme superoxide reductase (SOR) degrades superoxide via reduction. Biomimetic analogues which provide insight into why nature utilizes a trans-thiolate to promote SOR function are described. Spectroscopic and/or structural characterization of the first examples of thiolate-ligated Fe (III)-peroxo complexes provides important benchmark parameters for the identification of biological intermediates. Oxidative addition of superoxide is favored by low redox potentials. The trans influence of the thiolate appears to significantly weaken the Fe-O peroxo bond, favoring proton-induced release of H 2O 2 from a high-spin Fe(III)-OOH complex.
authors.affiliation: The Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, USA.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Kovacs
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Brines
mesh_terms: D001665:Binding Sites; D003545:Cysteine / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D008024:Ligands; D008958:Models, Molecular; D009251:NADPH-Ferrihemoprotein Reductase / Q000737:chemistry; D019159:Nonheme Iron Proteins / Q000737:chemistry* / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry*
chemical_list: D008024:Ligands; D019159:Nonheme Iron Proteins; D013438:Sulfhydryl Compounds; D013455:Sulfur; D006861:Hydrogen Peroxide; D010088:Oxidoreductases; C121849:superoxide reductase; D009251:NADPH-Ferrihemoprotein Reductase; D003545:Cysteine