Redox properties of an engineered purple Cu(A) azurin.
Redox properties of an engineered purple Cu(A) azurin.
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工程紫色 Cu(A) 天青蛋白的氧化还原特性。
DOI：
10.1016/s0003-9861(02)00282-5
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发表时间：
2002
影响因子：
3.9
通讯作者：
Davidson,VictorL
中科院分区：
文献类型：
--
作者：
Sun,Dapeng;Wang,Xiaotang;Davidson,VictorL
紫色铜中心是一类双核混合价铜配合物，存在于细胞色素c氧化酶和一氧化二氮还原酶中。通过将含有铜绿假单胞菌天青蛋白的天然I型铜中心的三个配体的氨基酸序列的一部分替换为来自铜绿副球菌的细胞色素c氧化酶的CuA中心的相应序列部分来形成工程化的CuA蛋白[Proc.Natl. Acad. Sci. USA 93（1996）461]。用循环伏安法和光谱化学滴定法测定了CuA-azurin的氧化还原中点电位（Em）分别为+399 mV 10和+380 mV 2 mV。得到的n值为1，表明氧化还原反应在混合价态和完全还原态之间循环。然而，天然天青蛋白的Emvalue是pH依赖性的，而CuA天青蛋白的Emvalue不是pH依赖性的，如对于CuAcenter所预期的。的氧化还原性能的相似性和差异进行了讨论，在已知的晶体结构的CuAcenters在细胞色素c氧化酶和CuAazurin。
Purple CuAcenters are a class of binuclear, mixed-valence copper complexes found in cytochrome c oxidase and nitrous oxide reductase. An engineered CuAprotein was formed by replacing a portion of the amino acid sequence that contains three of the ligands to the native type I copper center of Pseudomonas aeruginosa azurin with the corresponding portion of sequence from the CuAcenter of cytochrome c oxidase from Paracoccus denitrificans [Proc. Natl. Acad. Sci. USA 93 (1996) 461]. Oxidation–reduction midpoint potential (Em) values of the CuAazurin of +399±10 and +380±2mV, respectively, were determined by cyclic voltammetry and spectrochemical titration. An n value of one was obtained, indicating that the redox reaction is cycling between the mixed valence and the fully reduced states. Whereas the Emvalue of native azurin is pH dependent, the Emvalue of CuAazurin is not, as expected for the CuAcenter. Similarities and differences in the redox properties are discussed in terms of the known crystal structures of CuAcenters in cytochrome c oxidase and CuAazurin.