Inhibitor-enhanced electron transfer: copper cytochrome c as a redox-inert probe of ternary complexes.
Inhibitor-enhanced electron transfer: copper cytochrome c as a redox-inert probe of ternary complexes.
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抑制剂增强电子转移：铜细胞色素 c 作为三元复合物的氧化还原惰性探针。
DOI：
10.1126/science.7618081
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Hoffman,BM
中科院分区：
文献类型：
--
作者：
Zhou,JS;Nocek,JM;DeVan,ML;Hoffman,BM
铜取代的细胞色素c（CuCc）作为一种结构可靠的氧化还原惰性抑制剂，被用来研究Cc分子与细胞色素c过氧化物酶（CcP）之间的电子转移（ET）机制。这种抑制剂通过其铁（III）伴侣（Fe 3 +Cc或Fe 3 +CcP）增强锌取代蛋白质（ZnCcP或ZnCc）的三重激发态的光诱导ET淬灭。这些结果表明，CcP和Cc形成三元复合物，其中一个Cc分子在具有低ET反应性的CcP的表面结构域紧密结合，而第二个Cc分子在具有显著更大（β 103）反应性的第二结构域弱结合1：1复合物。这些结果也排除了在第二结构域结合的Cc协同增强ET至第一结构域的Cc的可能性。观察到的光产生的ET中间体的多相动力学不反映在三元复合物中的两个Cc分子之间的电子自交换。
Copper-substituted cytochrome c (CuCc) has been used as a structurally faithful, redoxinert inhibitor to probe the mechanism of electron transfer (ET) between Cc molecules and cytochrome c peroxidase (CcP). This inhibitor enhances photoinduced ET quenching of the triplet excited state of a zinc-substituted protein (ZnCcP or ZnCc) by its iron(III) partner (Fe3+Cc or Fe3+CcP). These results show that CcP and Cc form a ternary complex in which one Cc molecule binds tightly at a surface domain of CcP having low ET reactivity, whereas the second Cc molecule binds weakly to the 1:1 complex at a second domain with markedly greater (∼103) reactivity. These results also rule out the possibility that Cc bound at the second domain cooperatively enhances ET to Cc at the first domain. The multiphasic kinetics observed for the photoproduced ET intermediate do not reflect electron self-exchange between two Cc molecules within the ternary complex.