Mechanism and atomic structure of superoxide dismutase.
The active site Cu ion in Cu,Zn superoxide dismutase is alternately oxidized and reduced during the enzymatic dismutation of superoxide to hydrogen peroxide and molecular oxygen. For oxidized Cu,Zn superoxide dismutase, an atomic structure has been determined for the human enzyme at 2.5 A resolution. The resolution of the bovine enzyme structure has been extended to 1.8 A. Atomic resolution data has been collected for reduced and inhibitor-bound Cu,Zn superoxide dismutases, and the interpretation of the electron density difference maps is in progress. The geometry and molecular surfaces of the active sites in these structures, together with biochemical data, suggest a specific model for the enzyme mechanism. Similarities in the active site geometry of the Mn and Fe superoxide dismutases with the Cu,Zn enzyme suggest that dismutation in these enzymes may follow a similar mechanism.
Roberts
V A
VA
Department of Molecular Biology, Research Institute of Scripps Clinic, La Jolla, California 92037.
Fisher
C L
CL
Redford
S M
SM
McRee
D E
DE
Parge
H E
HE
Getzoff
E D
ED
Tainer
J A
JA
D000818:Animals; D001665:Binding Sites; D002417:Cattle; D003300:Copper; D004578:Electron Spin Resonance Spectroscopy; D006801:Humans; D007501:Iron; D009682:Magnetic Resonance Spectroscopy; D008345:Manganese; D008958:Models, Molecular; D015394:Molecular Structure; D010084:Oxidation-Reduction; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D013482:Superoxide Dismutase / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D014961:X-Ray Diffraction; D015032:Zinc
D013481:Superoxides; D008345:Manganese; D003300:Copper; D007501:Iron; D013482:Superoxide Dismutase; D015032:Zinc