植物蛋白质S-亚硝基化修饰的检测与分析

S-亚硝基化是一种重要的蛋白质翻译后修饰方式, 是指一氧化氮(NO)基团共价连接至靶蛋白特定半胱氨酸残基的自由巯基, 从而形成S-亚硝基硫醇(SNO)的过程。S-亚硝基化修饰广泛存在于各有机体中, 通过改变蛋白质生化活性、稳定性、亚细胞定位以及蛋白质-蛋白质相互作用等机制而调控不同的生物学过程或信号通路。在蛋白质S-亚硝基化检测分析方法中, 最为广泛使用的是生物素转化法(biotin switch assay), 其基本原理是首先封闭未被修饰的自由巯基, 进而将被修饰的SNO基团特异地还原为自由巯基并使用生物素将其特异标记。被生物素标记的半胱氨酸残基(即被修饰位点)可进一步通过蛋白质免疫印迹和/或质谱等方法进行检测分析。该文详细描述了植物蛋白质样品的体内和体外生物素转化法的实验流程, 并对实验过程中的注意事项进行了讨论。

Detection and Analysis of Protein S-nitrosylation in Plants

S-nitrosylation is an important protein posttranslational modification, involved in covalently linking a nitric oxide (NO) molecule to the thiol group of a cysteine residue to generate S-nitrosothiols. S-nitrosylation regulates multiple biological processes by modulating protein activity, stability, subcellular localization and protein-protein interactions. The biotin-switch assay is one of the most-often used methods to detect and analyze protein S-nitrosylation. In principle, the free thiols in a target protein are first blocked, followed by reducing the S-nitrosothiols of the target protein to free thiols by ascorbate, which are subsequently labelled by biotin to form biotinylated proteins. The biotin-labelled sample was assayed by immunoblotting and mass spectrometry. Here, we present detailed experimental procedures for the in vitro and in vivo biotin-switch methods and give advice on key troubleshooting solutions.