Metal sites of copper-zinc superoxide dismutase

Author(s): Beem KM, Richardson DC, Rajagopalan KV


Silver-copper and silver-cobalt proteins have been prepared in which Ag+ resides in the native copper site of superoxide dismutase and either Cu2+ of Co2+ reside in the zinc site. The electron paramagnetic resonance (EPR) spectrum of the copper and the visible absorption spectrum of the cobalt greatly resemble those of either Cu4 of Cu2,Cu2,Co2 proteins, respectively, in which the copper of the native copper sites has been reduced. It was found that, unlike cyanide, azide anion would not perturb the EPR spectrum of Ag2,Cu2 protein. Since azide produces the same perturbation upon the EPR spectrum of native and Cu2 proteins, it must bind to the copper and not the zinc of superoxide dismutase. A model of the metal sites of the enzyme has been fitted to a 3-A electron-density map using an interactive molecular graphics display. The model shows that histidine-61, which appears to bind both copper and zinc, does not lie in the plane of the copper and its three other histidine ligands, but occupies a position intermediate between planar and axial. This feature probably accounts for the rhombicity of the EPR spectrum and the activity of the enzyme.

Similar Articles

Global prevalence of diabetes: estimates for the year 2000 and projections for 2030

Author(s): Wild S, Roglic G, Green A, Sicree R, King H

Oxidative stress, nitric oxide, and diabetes

Author(s): Pitocco D, Zaccardi F, Di Stasio E, Romitelli F, Santini SA, et al.

Oxidative stress, diabetes, and diabetic complications

Author(s): Wei W, Liu Q, Tan Y, Liu L, Li X, et al.

Selenium: biochemical role as a component of glutathione peroxidase

Author(s): Rotruck JT, Pope AL, Ganther HE, Swanson AB, Hafeman DG, et al.

An iron-based cytosolic catalase and superoxide dismutase mimic complex

Author(s): Horn A Jr, Parrilha GL, Melo KV, Fernandes C, Horner M, et al.

The protective effect of montelukast sodium on carbon tetrachloride induced hepatopathy in rat

Author(s): Cuciureanu M, Caruntu ID, Paduraru O, Stoica B, Jerca L, et al.

A bicarbonate-alkaline mineral water protects from ethanol-induced hemorrhagic gastric lesions in mice

Author(s): Nassini R, Andrè E, Gazzieri D, De Siena G, Zanasi A, et al.

Anti-diabetic effect of alkaline-reduced water on OLETF rats

Author(s): Jin D, Ryu SH, Kim HW, Yang EJ, Lim SJ, et al.

Electrolyzed-reduced water scavenges active oxygen species and protects DNA from oxidative damage

Author(s): Shirahata S, Kabayama S, Nakano M, Miura T, Kusumoto K, et al.

Haemoglobin A1c levels and subsequent cardiovascular disease in persons without diabetes: a meta-analysis of prospective cohorts

Author(s): Santos-Oliveira R, Purdy C, da Silva MP, dos Anjos Carneiro-Leão AM, Machado M, et al.