title: Functional expression and characterization  of a cytosolic copper/zinc-superoxide dismutase  of Spirometra erinacei.
abstract: Spirometra erinacei is a pseudophyllidean tapeworm which inhabits the intestines of cats and dogs. The infections are usually asymptomatic in these animals, but the infection of the plerocercoid larvae of the parasite, spargana, cause sparganosis in other vertebrates, including human. In this study, we identified a gene encoding the copper/zinc-superoxide dismutase of S. erinacei (SeCuZn-SOD) and partially characterized the biochemical and functional properties of the enzyme. The open reading frame of SeCuZnSOD was 465 bp that encodes 154 amino acids. The characteristic amino acid residues and motifs required for coordinating copper and zinc enzymatic function were well conserved. The genomic length of the SeCuZnSOD was 1,985 bp consisting of three exons that are separated by two introns. SeCuZnSOD is a typical cytosolic form which shares similar biochemical properties, including broad pH optima and inhibition profile by KCN and H(2)O(2), with cytosolic Cu/Zn-SODs of other organisms. SeCuZnSOD was functionally expressed in both S. erinacei plerocercoid larvae and adult worms, and its expression level was significantly increased when the plerocercoid larvae were treated with paraquat. The enzyme may play essential roles for survival of the parasite not only by protecting itself from endogenous oxidative stress, but also by detoxifying oxidative killing of the parasite by host immune effector cells.
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
authors.forename: Ai-Hua
authors.initials: AH
authors.lastname: Li
authors.forename: Byoung-Kuk
authors.initials: BK
authors.lastname: Na
authors.forename: Sung-Kyu
authors.initials: SK
authors.lastname: Ahn
authors.forename: Shin-Hyeong
authors.initials: SH
authors.lastname: Cho
authors.forename: Jhang-Ho
authors.initials: JH
authors.lastname: Pak
authors.forename: Yun-Kyu
authors.initials: YK
authors.lastname: Park
authors.forename: Tong-Soo
authors.initials: TS
authors.lastname: Kim
mesh_terms: D000818:Animals; D001665:Binding Sites; D017124:Conserved Sequence; D018509:DNA, Helminth / Q000737:chemistry / Q000235:genetics; D004285:Dogs; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004795:Enzyme Stability; D005091:Exons; D020869:Gene Expression Profiling; D006861:Hydrogen Peroxide / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007438:Introns; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D011190:Potassium Cyanide / Q000494:pharmacology; D017422:Sequence Analysis, DNA; D012911:Snakes; D013146:Spirometra / Q000201:enzymology* / Q000302:isolation & purification; D013482:Superoxide Dismutase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
chemical_list: D018509:DNA, Helminth; D004791:Enzyme Inhibitors; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase; D011190:Potassium Cyanide