Atomic structures of wild-type and thermostable mutant recombinant human Cu,Zn superoxide dismutase.
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Parge HE, Hallewell RA, Tainer JA
Atomic structures of wild-type and thermostable mutant recombinant human Cu,Zn superoxide dismutase.
Proc Natl Acad Sci U S A. 1992 Jul 1;89(13):6109-13.
- PubMed ID
- 1463506 [ View in PubMed]
- Abstract
Superoxide dismutase enzymes protect aerobic organisms from oxygen-mediated free-radical damage. Crystallographic structures of recombinant human Cu,Zn superoxide dismutase have been determined, refined, and analyzed at 2.5 A resolution for wild-type and a designed thermostable double-mutant enzyme (Cys-6----Ala, Cys-111----Ser). The 10 subunits (five dimers) in the crystallographic asymmetric unit form an unusual stable open lattice with 80-A-diameter channels. The 10 independently fit and refined subunits provide high accuracy, error analysis, and insights on loop conformations. There is a helix dipole interaction with the Zn site, and 14 residues form two or more structurally conserved side-chain to main-chain hydrogen bonds that appear critical to active-site architecture, loop conformation, and the increased stability resulting from the Cys-111----Ser mutation.