Roberts V A, Fisher C L, Redford S M, McRee D E, Parge H E, Getzoff E D, Tainer J A
Department of Molecular Biology, Research Institute of Scripps Clinic, La Jolla, California 92037.
Free Radic Res Commun. 1991;12-13 Pt 1:269-78. doi: 10.3109/10715769109145795.
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.
在超氧化物歧化为过氧化氢和分子氧的酶促反应过程中，铜锌超氧化物歧化酶中的活性位点铜离子会交替发生氧化和还原。对于氧化态的铜锌超氧化物歧化酶，已测定出人类酶在2.5埃分辨率下的原子结构。牛酶结构的分辨率已提高到1.8埃。已收集到还原态和结合抑制剂的铜锌超氧化物歧化酶的原子分辨率数据，对电子密度差图谱的解读正在进行中。这些结构中活性位点的几何形状和分子表面，连同生化数据，提示了一种酶作用机制的特定模型。锰和铁超氧化物歧化酶的活性位点几何形状与铜锌酶相似，这表明这些酶中的歧化反应可能遵循类似的机制。
