与嗜热栖热菌 Rieske 蛋白的[2Fe-2S]簇相关的氧化还原连接的可电离基团的证据。
Evidence for a redox-linked ionizable group associated with the [2Fe-2S] cluster of Thermus Rieske protein.
作者信息
Kuila D, Fee J A
出版信息
J Biol Chem. 1986 Feb 25;261(6):2768-71.
The [2Fe-2S] clusters of Thermus Rieske protein, which were previously found to have nitrogen atoms coordinated directly to the iron (Cline, J.F., Hoffman, B.M., LaHaie, E., Ballou, D.P., and Fee, J.A. (1985) J. Biol. Chem. 260, 3251-3254), are now shown to have a tightly linked ionization that affects the spectral and redox properties of the cluster. The data are consistent with the reactions LH+, Fe3+ in equilibrium with L-Fe3+ +H+ and L-Fe3+ + H+ + e in equilibrium with LH+, Fe2+, where L is coordinated to Fe3+ but LH+ may not be, depending on its structure. The pKa of the protonic equilibrium is approximately 8 and the midpoint potential, Em7, is approximately 140 mV. Possible structures of L are suggested.
嗜热栖热菌 Rieske 蛋白的[2Fe-2S]簇，此前发现其氮原子直接与铁配位（克莱恩，J.F.，霍夫曼，B.M.，拉海，E.，巴卢，D.P.，和费，J.A.（1985 年）《生物化学杂志》260，3251 - 3254），现在表明其具有紧密相连的电离作用，影响该簇的光谱和氧化还原性质。数据与反应 LH⁺、Fe³⁺ 与 L - Fe³⁺ + H⁺ 处于平衡以及 L - Fe³⁺ + H⁺ + e 与 LH⁺、Fe²⁺ 处于平衡一致，其中 L 与 Fe³⁺ 配位，但 LH⁺ 可能不与 Fe³⁺ 配位，这取决于其结构。质子平衡的 pKa 约为 8，中点电位 Em7 约为 140 mV。文中提出了 L 的可能结构。
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