New insight into the mode of action of nickel superoxide dismutase by investigating metallopeptide substrate models.
New insight into the mode of action of nickel superoxide dismutase by investigating metallopeptide substrate models.
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通过研究金属肽底物模型，对镍超氧化物歧化酶的作用模式有了新的认识。
DOI：
10.1002/chem.200800870
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
G. Buntkowsky
中科院分区：
文献类型：
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作者：
D. Tietze;H. Breitzke;D. Imhof;E. Kothe;James Weston;G. Buntkowsky
第一次，镍超氧化物歧化酶（NiSOD）模型的底物加合物的存在下，从天蓝色链霉菌NiSOD的活性形式的N末端的前9个残基的基础上，已被证明和加合物已被分离。该加合物基于氰化物阴离子（CN（-）），作为超氧阴离子（O（2）（*-））的底物类似物，以及镍金属肽H-HCDLPCGVY-NH（2）-Ni。光谱学研究，包括IR，UV/维斯，和液体和固态NMR光谱，显示一个单一的镍结合的氰化物阴离子，这是嵌入在金属肽结构。这个复杂的揭示了新的问题，无论是NiSOD酶的作用模式是一个内部或外部的领域机制。鉴于之前的讨论偏向于外层电子转移机制，因为从未观察到氰化物或叠氮化物部分与镍活性位点的结合，我们的结果清楚地表明有利于O（2）（*-）离子的内球电子转移机制，从而使底物与NiSOD活性位点中的Ni原子连接。
For the first time, the existence of a substrate adduct of a nickel superoxide dismutase (NiSOD) model, based on the first nine residues from the N terminus of the active form of Streptomyces coelicolor NiSOD, has been proven and the adduct has been isolated. This adduct is based on the cyanide anion (CN(-)), as a substrate analogue of the superoxide anion (O(2)(*-)), and the nickel metallopeptide H-HCDLPCGVY-NH(2)-Ni. Spectroscopic studies, including IR, UV/Vis, and liquid- and solid-state NMR spectroscopy, show a single nickel-bound cyanide anion, which is embedded in the metallopeptide structure. This complex sheds new light on the question of whether the mode of action of the NiSOD enzyme is an inner- or outer-sphere mechanism. Whereas discussion was previously biased in favor of an outer-sphere electron-transfer mechanism due to the fact that binding of cyanide or azide moieties to the nickel active site had never been observed, our results are a clear indication in favor of the inner-sphere electron-transfer mechanism for the disproportionation of the O(2)(*-) ion, whereby the substrate is attached to the Ni atom in the active site of the NiSOD.