Open AccessPurification, crystallization and X‐ray structures of the two manganese superoxide dismutases from Caenorhabditis elegans
Author(s) -
Trinh Chi H.,
Hunter Thérèse,
Stewart Emma E.,
Phillips Simon E. V.,
Hunter Gary J.
Publication year - 2008
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309108037056
Subject(s) - tetramer , homotetramer , superoxide dismutase , dimer , chemistry , crystallography , protein subunit , stereochemistry , caenorhabditis elegans , enzyme , biochemistry , organic chemistry , gene
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 Å resolution, respectively. Pink crystals formed in space group P 4 1 2 1 2 for each, with unit‐cell parameters a = b = 81.0, c = 137.4 Å for MnSOD‐2 and a = b = 81.8, c = 136.0 Å 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.