PDF(Pubmed)
Abstract：
Oxidative modifications of amino acid side chains in proteins are a hallmark of oxidative stress, and they are usually regarded as structural damage. However, amino acid oxidation may also have a protective effect and may serve regulatory or structural purposes. Here, we have attempted to characterize the global redox role of the 20 proteinogenic amino acids in animals by analyzing their usage frequency in 5 plausible evolutionary paradigms of increased oxidative burden: (i) peroxisomal proteins versus all proteins, (ii) mitochondrial proteins versus all proteins, (iii) mitochondrially encoded respiratory chain proteins versus all mitochondrial proteins, (iv) proteins from long-lived animals versus those from short-lived animals, and (v) proteins from aerobic, free-living animals versus those from facultatively anaerobic animals. We have found that avoidance of cysteine in the oxidative condition was the most pronounced and significant variation in the majority of comparisons. Beyond this preeminent pattern, only local signals were observed, primarily increases in methionine and glutamine as well as decreases in serine and proline. Hence, certain types of cysteine oxidation appear to enforce its proteome-wide evolutionary avoidance despite its essential role in disulfide bond formation and metal ligation. The susceptibility to oxidation of all other amino acids appears to be generally unproblematic, and sometimes advantageous.
摘要：
蛋白质氨基酸侧链的氧化修饰是氧化应激的标志,它们通常被视为结构损坏。然而,氨基酸氧化也可能具有保护作用，并且可以用于调节或结构目的。这里,我们试图通过分析20个蛋白质氨基酸在动物中的整体氧化还原作用，在5种氧化负担增加的合理进化范式中分析它们的使用频率：（i）过氧化物酶体蛋白与所有蛋白，（ii）线粒体蛋白质与所有蛋白质，（iii）线粒体编码的呼吸链蛋白与所有线粒体蛋白，（iv）来自长寿动物的蛋白质与来自短命动物的蛋白质，和（v）来自有氧的蛋白质，自由生活的动物与来自兼性厌氧动物的动物。我们已经发现,在大多数比较中,在氧化条件下避免半胱氨酸是最显著和显著的变化。除了这种卓越的模式，只观察到本地信号，主要是蛋氨酸和谷氨酰胺的增加以及丝氨酸和脯氨酸的减少。因此，尽管某些类型的半胱氨酸氧化在二硫键形成和金属连接中起着重要作用，但似乎可以增强其蛋白质组范围的进化回避。所有其他氨基酸的氧化敏感性似乎通常没有问题，有时是有利的。
