title: Identification of three Superoxide dismutase genes from a Geobacillus sp.
abstract: We report the characterization of three Superoxide dismutase (sod) genes isolated from a bacterium in the Geobacillus genus. We isolated the bacterium from high-temperature pond mud and used 16S rRNA gene sequence to confirm its identity in the Geobacillus genus. The three genes Mn-sod, Fe/Mn-sod, and Cu/Zn-sod were cloned and analyzed. Their open reading frames are Mn-sod: 615 bp encoding a 204 amino acid protein; Fe/Mn-sod: 1,236 bp encoding a 411 amino acid protein; Cu/Zn-sod: 522 bp encoding a 173 amino acid protein. When these sod genes were expressed in Escherichia coli, only Mn-SOD was able to be purified. The activity of the purified Mn-SOD we got was about 2,730 U/mg. Studies of this Mn-SOD showed that it was thermostable at 60°, had 70% activity at 80° after 2.5 h, and still had 30% activity at 90° after 2.5 h. Mn-SOD activity required the ion Mn²+. Based on gel electrophoresis, we deduced that this Mn-SOD was a homotetramer. No activity was detected after the other two genes (Fe/Mn-sod, Cu/Zn-sod) were expressed in Escherichia coli, but activities were detected when expressed in Pichia pastoris.
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, No. 12 Zhongguancun South Street, 100081 Beijing, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Zou
authors.forename: Ling
authors.initials: L
authors.lastname: Yang
authors.forename: Guoxian
authors.initials: G
authors.lastname: Liu
authors.forename: Yinv
authors.initials: Y
authors.lastname: Li
authors.forename: Yuexiong
authors.initials: Y
authors.lastname: Zhu
authors.forename: Zhifang
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000818:Animals; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D056506:Geobacillus / Q000235:genetics* / Q000378:metabolism; D006358:Hot Temperature; D016366:Open Reading Frames; D013482:Superoxide Dismutase / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D013482:Superoxide Dismutase