title: Crystal structure and biochemical characterization of a manganese superoxide dismutase from Chaetomium thermophilum.
abstract: A manganese superoxide dismutase from the thermophilic fungus Chaetomium thermophilum (CtMnSOD) was expressed in Pichia pastoris and purified to homogeneity. Its optimal temperature was 60°C with approximately 75% of its activity retained after incubation at 70°C for 60min. Recombinant yeast cells carrying C. thermophilum mnsod gene exhibited higher stress resistance to salt and oxidative stress-inducing agents than control yeast cells. In an effort to provide structural insights, CtMnSOD was crystallized and its structure was determined at 2.0Å resolution. The overall architecture of CtMnSOD was found similar to other MnSODs with highest structural similarities obtained against a MnSOD from the thermotolerant fungus Aspergillus fumigatus. In order to explain its thermostability, structural and sequence analysis of CtMnSOD with other MnSODs was carried out. An increased number of charged residues and an increase in the number of intersubunit salt bridges and the Thr:Ser ratio were identified as potential reasons for the thermostability of CtMnSOD.
authors: Turku Centre for Biotechnology, University of Turku, BioCity, Turku 20521, Finland; Åbo Akademi University, BioCity, Turku 20521, Finland.
authors: Teemu
authors: T
authors: Haikarainen
authors: Turku Centre for Biotechnology, University of Turku, BioCity, Turku 20521, Finland; Åbo Akademi University, BioCity, Turku 20521, Finland.
authors: Clémence
authors: C
authors: Frioux
authors: Department of Environmental Biology, Shandong Agricultural University, Taian, Shandong 271018, China; Department of Chemistry and Chemical Engineering, Taishan Medical College, Taian, Shandong 271016, China.
authors: Li-Qing
authors: LQ
authors: Zhnag
authors: Department of Environmental Biology, Shandong Agricultural University, Taian, Shandong 271018, China.
authors: Duo-Chuan
authors: DC
authors: Li
authors: Turku Centre for Biotechnology, University of Turku, BioCity, Turku 20521, Finland; Åbo Akademi University, BioCity, Turku 20521, Finland. Electronic address: tassos.papageorgiou@btk.fi.
authors: Anastassios C
authors: AC
authors: Papageorgiou
mesh_terms: D000595:Amino Acid Sequence; D020134:Catalytic Domain; D002597:Chaetomium / Q000201:enzymology*; D018360:Crystallography, X-Ray; D059865:Endoplasmic Reticulum Stress / Q000502:physiology; D004795:Enzyme Stability; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010843:Pichia; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D013482:Superoxide Dismutase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D013482:Superoxide Dismutase
keywords: Antioxidant; Chaetomium thermophilum manganese superoxide dismutase; CtMnSOD; Dismutation; Fungal enzyme; Metal binding; Oxidative stress; RSAA; SAA; Thermostability; relative solvent accessible area; solvent accessible area