title: Purification, crystallization and X-ray structures of the two manganese superoxide dismutases from Caenorhabditis elegans.
abstract: Caenorhabditis elegans expresses two manganese superoxide dismutase enzymes (MnSOD-2 and MnSOD-3) that are targeted to the mitochondrion. MnSOD-2 is constitutively expressed, while synthesis of MnSOD-3 is inducible. The structures of these two mononuclear metalloenzymes have been determined to 1.8 and 1.7 A resolution, respectively. Pink crystals formed in space group P4(1)2(1)2 for each, with unit-cell parameters a = b = 81.0, c = 137.4 A for MnSOD-2 and a = b = 81.8, c = 136.0 A for MnSOD-3. The final structure of MnSOD-3 was refined to R = 21.6% and R(free) = 26.2% at 293 K, and R = 18.9% and R(free) = 22.6% at 100 K, while that of MnSOD-2 was refined to R = 16.9% and R(free) = 20.1% at 100 K. The asymmetric unit cell is comprised of two subunits. The resulting structures are very similar to that of human MnSOD and form a tetramer corresponding to a dimer of dimers. The subunit interface between dimers is comprised of two four-helix bundles that stabilize the biologically significant homotetramer.
authors.affiliation: Astbury Centre for Structural Molecular Biology, Institute of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, England.
authors.forename: Chi H
authors.initials: CH
authors.lastname: Trinh
authors.forename: Thérèse
authors.initials: T
authors.lastname: Hunter
authors.forename: Emma E
authors.initials: EE
authors.lastname: Stewart
authors.forename: Simon E V
authors.initials: SE
authors.lastname: Phillips
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Hunter
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000201:enzymology* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013482:Superoxide Dismutase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; D013482:Superoxide Dismutase