Zimmermann Jürgen, Kühne Ronald, Sylvester Marc, Freund Christian
Protein Engineering Group, Leibniz-Institut für Molekulare Pharmakologie und Freie Universität Berlin, 13125 Berlin, Germany.
Biochemistry. 2007 Jun 12;46(23):6971-7. doi: 10.1021/bi700437r. Epub 2007 May 19.
Oxidation-induced conformational changes in proteins provide a powerful mechanism to sense the redox state of a living cell. In contrast to the unspecific and often irreversible oxidation of intracellular proteins during severe oxidative stress, regulatory redox events need to have specific and transient effects on cellular targets. Here we present evidence for the reversible formation of a vicinal disulfide bond in a prototypic protein interaction domain. NMR spectroscopy was used to determine the structure of the N-terminal hSH3 domain (hSH3N) of the immune cell protein ADAP (adhesion and degranulation promoting adapter protein) in the reduced and oxidized states. An eight-membered ring formed upon oxidation of two neighboring cysteines leads to significant changes in the variable arginine-threonine (RT) loop of the hSH3N domain and alters the helix-sheet packing of the domain. The redox potential for this structural transition is -228 mV at pH 7.4. This is compatible with a role of the cysteinylcysteine moiety in redox signaling during T cell activation.
蛋白质中氧化诱导的构象变化提供了一种强大的机制来感知活细胞的氧化还原状态。与严重氧化应激期间细胞内蛋白质的非特异性且通常不可逆的氧化不同，调节性氧化还原事件需要对细胞靶点产生特异性和短暂的影响。在此，我们提供了在一个原型蛋白质相互作用结构域中可逆形成邻二硫键的证据。核磁共振光谱用于确定免疫细胞蛋白ADAP（黏附与脱颗粒促进衔接蛋白）的N端hSH3结构域（hSH3N）在还原态和氧化态下的结构。两个相邻半胱氨酸氧化后形成的八元环导致hSH3N结构域可变的精氨酸 - 苏氨酸（RT）环发生显著变化，并改变了该结构域的螺旋 - 折叠堆积。在pH 7.4时，这种结构转变的氧化还原电位为 -228 mV。这与半胱氨酰半胱氨酸部分在T细胞激活过程中的氧化还原信号传导作用相一致。
