The mitochondrial cyanide-resistant oxidase: structural conservation amid regulatory diversity.
The mitochondrial cyanide-resistant oxidase: structural conservation amid regulatory diversity.
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DOI：
10.1016/s0005-2728(00)00181-x
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发表时间：
2000-08
期刊：
影响因子：
--
通讯作者：
J. Siedow;A. L. Umbach
中科院分区：
文献类型：
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作者：
J. Siedow;A. L. Umbach
所有植物、许多真菌和一些原生动物的线粒体都含有一种抗氰化物的替代氧化酶，它的功能与细胞色素c氧化酶平行，是电子转移链上的末端氧化酶。近年来，对替代氧化酶的结构和潜在调控特征的表征取得了相当大的进展。活性部位被认为包含一个属于核糖核苷酸还原酶R2家族的双铁中心，并且已经进行了四螺旋束的建模，以在C末端三分之二的蛋白质中容纳这个活性部位。在所有已知的替代氧化酶中，该活性部位的结构特征是保守的。交替氧化酶的翻译后调节功能在不同的生物体中变化更大。植物氧化酶是二聚体，可以被α-酮酸或琥珀酸刺激，这分别取决于植物蛋白N-末端区域保守的氨基酸块中是否存在关键的半胱氨酸残基。真菌和原生动物交替氧化酶一般以单体形式存在，不受有机酸刺激，但可被嘌呤核苷酸刺激。这些不同调控功能的起源尚不清楚，但与蛋白质N末端三分之一的序列差异有关。
Mitochondria from all plants, many fungi and some protozoa contain a cyanide-resistant, alternative oxidase that functions in parallel with cytochrome c oxidase as the terminal oxidase on the electron transfer chain. Characterization of the structural and potential regulatory features of the alternative oxidase has advanced considerably in recent years. The active site is proposed to contain a di-iron center belonging to the ribonucleotide reductase R2 family and modeling of a four-helix bundle to accommodate this active site within the C-terminal two-thirds of the protein has been carried out. The structural features of this active site are conserved among all known alternative oxidases. The post-translational regulatory features of the alternative oxidase are more variable among organisms. The plant oxidase is dimeric and can be stimulated by either α-keto acids or succinate, depending upon the presence or absence, respectively, of a critical cysteine residue found in a conserved block of amino acids in the N-terminal region of the plant protein. The fungal and protozoan alternative oxidases generally exist as monomers and are not subject to organic acid stimulation but can be stimulated by purine nucleotides. The origins of these diverse regulatory features remain unknown but are correlated with sequence differences in the N-terminal third of the protein.