Institute for Medical Biochemistry and Molecular Biology, University Medicine, University of Greifswald, Greifswald, Germany.
Department of Neurology, Medical Faculty, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany.
Nat Commun. 2020 Jul 10;11(1):3445. doi: 10.1038/s41467-020-17323-0.
Despite their very close structural similarity, CxxC/S-type (class I) glutaredoxins (Grxs) act as oxidoreductases, while CGFS-type (class II) Grxs act as FeS cluster transferases. Here we show that the key determinant of Grx function is a distinct loop structure adjacent to the active site. Engineering of a CxxC/S-type Grx with a CGFS-type loop switched its function from oxidoreductase to FeS transferase. Engineering of a CGFS-type Grx with a CxxC/S-type loop abolished FeS transferase activity and activated the oxidative half reaction of the oxidoreductase. The reductive half-reaction, requiring the interaction with a second GSH molecule, was enabled by switching additional residues in the active site. We explain how subtle structural differences, mostly depending on the structure of one particular loop, act in concert to determine Grx function.
尽管 CxxC/S 型（I 类）谷氧还蛋白（Grx）和 CGFS 型（II 类）谷氧还蛋白在结构上非常相似，但前者作为氧化还原酶，而后者作为 FeS 簇转移酶。在这里，我们表明 Grx 功能的关键决定因素是位于活性位点附近的独特环结构。通过将 CxxC/S 型 Grx 的 CGFS 型环进行工程改造，将其功能从氧化还原酶转变为 FeS 转移酶。将 CGFS 型 Grx 的 CxxC/S 型环进行工程改造，会消除其 FeS 转移酶活性并激活氧化还原酶的氧化半反应。需要与第二个 GSH 分子相互作用的还原半反应，可以通过切换活性位点中的其他残基来实现。我们解释了如何通过协调作用的细微结构差异（主要取决于一个特定环的结构）来决定 Grx 的功能。
