期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1992
卷号：89
期号：13
页码：6109-6113
DOI：10.1073/pnas.89.13.6109
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：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.
