title: A novel nickel-containing superoxide dismutase from Streptomyces spp.
abstract: A novel type of superoxide dismutase (SOD) was purified to apparent homogeneity from the cytosolic fractions of Streptomyces sp. IMSNU-1 and Strep. coelicolor ATCC 10147 respectively. Both enzymes were composed of four identical subunits of 13.4 kDa, were stable at pH 4.0-8.0 and up to 70 degrees C, and were inhibited by cyanide and H2O2 but little inhibited by azide. The atomic absorption analyses revealed that both enzymes contain 0.74 g-atom of nickel per mol of subunit. Both enzymes were different from iron-containing SOD and manganese-containing SOD from Escherichia coli, and copper- and zinc-containing SODs from Saccharomyces cerevisiae and bovine erythrocytes, with respect to amino acid composition, N-terminal amino acid sequence and cross-reactivity against antibody. The absorption spectra of both enzymes were identical, exhibiting maxima at 276 and 378 nm, and a broad peak at 531 nm. The EPR spectra of both enzymes were almost identical with that of NiIII in a tetragonal symmetry of NiIII-oligopeptides especially containing histidine. The apoenzymes, lacking in nickel, had no ability to mediate the conversion of superoxide anion radical to hydrogen peroxide, strongly indicating that NiIII plays a main role in these enzymes.
authors.affiliation: Department of Microbiology, College of Natural Sciences, Seoul National University, Republic of Korea.
authors.forename: H D
authors.initials: HD
authors.lastname: Youn
authors.forename: E J
authors.initials: EJ
authors.lastname: Kim
authors.forename: J H
authors.initials: JH
authors.lastname: Roe
authors.forename: Y C
authors.initials: YC
authors.lastname: Hah
authors.forename: S O
authors.initials: SO
authors.lastname: Kang
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004795:Enzyme Stability; D004912:Erythrocytes / Q000201:enzymology; D004926:Escherichia coli / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D015151:Immunoblotting; D008969:Molecular Sequence Data; D015394:Molecular Structure; D008970:Molecular Weight; D009532:Nickel / Q000032:analysis; D011487:Protein Conformation; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D013302:Streptomyces / Q000201:enzymology* / Q000235:genetics; D013482:Superoxide Dismutase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D013696:Temperature
chemical_list: D000596:Amino Acids; D004791:Enzyme Inhibitors; D009532:Nickel; D013482:Superoxide Dismutase