title: Expression of a novel thermostable Cu, Zn-superoxide dismutase from Chaetomium thermophilum in Pichia pastoris and its antioxidant properties.
abstract: A new superoxide dismutase (SOD) gene from the thermophilic fungus Chaetomium thermophilum (Ctsod) was cloned and expressed in Pichia pastoris and its gene product was characterized. The specific activity of the purified CtSOD was 2,170 U/mg protein. The enzyme was inactivated by KCN and H(2)O(2) but not by NaN(3), confirming that it belonged to the type of Cu, ZnSOD. The amino acid residues involved in coordinating copper and zinc were conserved. The recombinant CtSOD exhibited optimum activity at pH 6.5 and 60°C. The enzyme retained 65% of the maximum activity at 70°C for 60 min and the half-life was 22 and 7 min at 80 and 90°C, respectively. The recombinant yeast exhibited higher stress resistance than the control yeast cells to salt and superoxide-generating agents, such as paraquat and menadione.
authors.affiliation: Department of Environmental Biology, Shandong Agricultural University, Taian, 271018, Shandong, China.
authors.forename: Li-Qing
authors.initials: LQ
authors.lastname: Zhang
authors.forename: Fang-Xian
authors.initials: FX
authors.lastname: Guo
authors.forename: Hong-Quan
authors.initials: HQ
authors.lastname: Xian
authors.forename: Xiu-Juan
authors.initials: XJ
authors.lastname: Wang
authors.forename: An-Na
authors.initials: AN
authors.lastname: Li
authors.forename: Duo-Chuan
authors.initials: DC
authors.lastname: Li
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D001483:Base Sequence; D001709:Biotechnology; D002597:Chaetomium / Q000201:enzymology* / Q000235:genetics*; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D005800:Genes, Fungal; D018384:Oxidative Stress; D010843:Pichia / Q000201:enzymology* / Q000235:genetics*; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D054712:Salinity; D013482:Superoxide Dismutase / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D004271:DNA, Fungal; D004791:Enzyme Inhibitors; D005656:Fungal Proteins; D011994:Recombinant Proteins; D013482:Superoxide Dismutase