title: The mismetallation of enzymes during oxidative stress.
abstract: Mononuclear iron enzymes can tightly bind non-activating metals. How do cells avoid mismetallation? The model bacterium Escherichia coli may control its metal pools so that thermodynamics favor the correct metallation of each enzyme. This system is disrupted, however, by superoxide and hydrogen peroxide. These species oxidize ferrous iron and thereby displace it from many iron-dependent mononuclear enzymes. Ultimately, zinc binds in its place, confers little activity, and imposes metabolic bottlenecks. Data suggest that E. coli compensates by using thiols to extract the zinc and by importing manganese to replace the catalytic iron atom. Manganese resists oxidants and provides substantial activity.
authors.affiliation: From the Department of Microbiology, University of Illinois, Urbana, Illinois 61801 jimlay@illinois.edu.
authors.forename: James A
authors.initials: JA
authors.lastname: Imlay
mesh_terms: D002413:Cations, Divalent; D004926:Escherichia coli / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006861:Hydrogen Peroxide / Q000737:chemistry; D007501:Iron / Q000737:chemistry* / Q000378:metabolism; D008345:Manganese / Q000737:chemistry* / Q000378:metabolism; D008667:Metalloproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D013329:Structure-Activity Relationship; D013481:Superoxides / Q000737:chemistry; D015032:Zinc / Q000737:chemistry* / Q000378:metabolism
chemical_list: D002413:Cations, Divalent; D029968:Escherichia coli Proteins; D008667:Metalloproteins; D013481:Superoxides; D008345:Manganese; D006861:Hydrogen Peroxide; D007501:Iron; D015032:Zinc
keywords: Hydrogen Peroxide; Iron Metabolism; Manganese; Superoxide Ion; Zinc