Revealing the position of the substrate in nickel superoxide dismutase: a model study.
Revealing the position of the substrate in nickel superoxide dismutase: a model study.
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揭示镍超氧化物歧化酶中底物的位置：模型研究
DOI：
10.1002/anie.201005027
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发表时间：
2011
影响因子：
--
通讯作者：
G. Buntkowsky
中科院分区：
文献类型：
--
作者：
D. Tietze;S. Voigt;D. Mollenhauer;M. Tischler;D. Imhof;T. Gutmann;L. González;O. Ohlenschläger;H. Breitzke;M. Görlach;G. Buntkowsky
活性氧（ROS）是几种类型的癌症、炎症和相关疾病发展的主要因素。这些ROS不仅具有细胞毒性，而且还参与细胞信号传导对活性氧的保护对生物有机体至关重要。对于需氧生物，超氧化物歧化酶（sod）在保护细胞免受活性氧（ROS）的侵害中起主要作用，活性氧是由呼吸链的活性代谢物减少分子氧产生的由于其在生物学和医学上的重要性，sod是一个深入研究的主题，2010年前六个月发表了2000多篇论文。虽然这项研究已经使人们对它们的生物学功能和酶动力学有了详细的了解，但这些酶的确切作用方式仍不清楚，并提出了两种不同的机制缺乏知识的一个主要原因是sod的超氧化物降解的高催化速率常数（O2CÀ）。SODs通过将超氧阴离子自由基转化为过氧化氢和氧来破坏超氧阴离子自由基，其速率接近扩散极限（kcat> 2109 m À1 sÀ1）因此，与它们的作用有关的所有瞬态都太短，无法进行光谱表征。为此，开发了SODs模型系统。本文表明，研究镍超氧化物歧化酶（NiSOD）的模型系统能够阐明该酶的作用模式，并使在提出的机制之间做出决定成为可能。特别是，我们不仅能够揭示底物与酶的结合模式，还能够揭示酶活性位点中功能性水分子的存在。已知有三种独立的sod。它们含有双核（Cu, Zn）或单核（Fe, Mn, Ni）辅因子。[1b， 5] NiSOD是一种单核含镍金属酶，在催化过程中在NiII和NiIII之间循环。[3a, 4b， 6] NiSOD于1996年首次在链霉菌中发现。[5a]晶体学和光谱学研究给出了整个酶的结构和一个共价结合镍离子的活性位点的几何形状。镍离子嵌入在S. coelicolor NiSOD活性形式n端前6个氨基酸形成的所谓镍钩中（方案1）。[3a, 4b, 6,7]为了详细研究NiSOD酶的催化机制，基于S. coelicolor NiSOD活性形式n端前12、9、7或6个残基，建立了几种具有催化活性的金属肽NiSOD模型。[3b, c， 8]讨论了两种与底物结合不同的机制。根据底物是否结合在镍离子的第一配位球，它们分别被称为内球或外球电子转移（ET）机制。最近，我们中的一些人能够合成并表征金属肽-底物模型复合物，采用氰化物作为底物类似物。这些结果为内球ET机制提供了强有力的支持CuZnSODs的研究表明，氰化物作为一种非常有效的SODs抑制剂，非常适合于SODs的功能研究。与CuZnSOD一起，氰化物形成稳定的
Reactive oxygen species (ROS) are a major factor in the development of several types of cancer, inflammation, and related diseases. These ROS are not only cytotoxic but also involved in cell signaling.[1] The protection from ROS is of vital importance for biological organisms. For aerobic organisms, superoxide dismutases (SODs) play the major role in protecting cells from ROS, which are generated by the reduction of molecular oxygen by reactive metabolites of the respiratory chain.[2] Because of their biological and medical importance, SODs are a subject of intense research, which yielded more than 2000 publications in the first six months of 2010. While this research has led to detailed knowledge about their biological function and enzyme kinetics, the precise mode of action of these enzymes is still not known and two different mechanisms were proposed.[3] A major reason for this lack of knowledge is the high catalytic rate constants of superoxide degradation (O2CÀ) by SODs. SODs destroy the superoxide anion radical by converting it into hydrogen peroxide and oxygen with a rate near the diffusion limit (kcat> 2 109 m À1 sÀ1).[4] Thus all transients involved in their action are too short lived to be amenable for a spectroscopic characterization. For this reason model systems of SODs were developed. Herein we show that the investigation of a model system of the nickel superoxide dismutase (NiSOD) is able to shed light into the mode of action of this enzyme and makes it possible to decide between the proposed mechanisms. In particular we are able to reveal not only the mode of binding of the substrate to the enzyme also the presence of functional water molecules in the active site of the enzyme. Three independent classes of SODs are known. They contain either a dinuclear (Cu, Zn) or a mononuclear (Fe, Mn, Ni) cofactor.[1b, 5] NiSOD, as a mononuclear nickel-containing metalloenzyme, cycles between NiII and NiIII during catalysis.[3a, 4b, 6] NiSOD was first found in 1996 in Streptomyces.[5a] Crystallographic and spectroscopic studies give an impression of the structure of the whole enzyme and the geometry of its active site with a single covalently bound nickel ion. The nickel ion is embedded within the so-called nickel-hook formed by the first six amino acids of the N-terminus of the active form of S. coelicolor NiSOD (Scheme 1).[3a, 4b, 6, 7]For detailed investigations on the catalytic mechanism of the NiSOD enzyme, several catalytically active metallopeptide NiSOD models were developed based on the first 12, 9, 7, or 6 residues from the N-terminus of the active form of S. coelicolor NiSOD.[3b, c, 8] Two mechanisms were discussed [3], which differ in the binding of the substrate. Depending on whether the substrate is bound in the first coordination sphere of the nickel ion or not they are called inner-sphere or outersphere electron-transfer (ET) mechanism, respectively. Recently some of us were able to synthesize and characterize a metallopeptide–substrate model complex employing cyanide as a substrate analogue. these results gave strong support for the inner-sphere ET mechanism.[9] Studies of CuZnSODs have shown that cyanide, as a very powerful inhibitor of SODs, is ideally suited for functional studies of SODS. With CuZnSOD, cyanide forms a stable
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电子核双共振检测牛超氧化物歧化酶氰化物衍生物。
DOI：
10.1016/0167-4838(82)90134-0
发表时间：
1982
期刊：
Biochimica et biophysica acta
影响因子：
--
作者：
Harlan L. van Camp;R. Sands;James A. Fee
通讯作者：
James A. Fee
影响因子：
3.2
作者：
T. Emmler;I. Ayala;David N. Silverman;S. Hafner;A. Galstyan;Ernst-Walter Knapp;Gerd Buntkowsky
通讯作者：
T. Emmler;I. Ayala;David N. Silverman;S. Hafner;A. Galstyan;Ernst-Walter Knapp;Gerd Buntkowsky
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。
影响因子：
--
作者：
D. Tietze;H. Breitzke;D. Imhof;E. Kothe;James Weston;G. Buntkowsky
通讯作者：
G. Buntkowsky
影响因子：
2.9
作者：
G. Rotilio;A. Agrò;L. Calabrese;F. Bossa;P. Guerrieri;B. Mondovì
通讯作者：
B. Mondovì
含镍超氧化物歧化酶的结晶和通过 MAD 在 Ni K 边缘进行初步相测定。
DOI：
10.1107/s0907444902007345
发表时间：
2002
期刊：
Acta crystallographica. Section D, Biological crystallography
影响因子：
--
作者：
J. Wuerges;J. Lee;Sa‐Ouk Kang;K. Djinović Carugo
通讯作者：
K. Djinović Carugo