Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, United States.
Howard Hughes Medical Institute, California Institute of Technology, Pasadena, United States.
Elife. 2022 Jul 29;11:e79311. doi: 10.7554/eLife.79311.
The nitrogenase Fe protein mediates ATP-dependent electron transfer to the nitrogenase MoFe protein during nitrogen fixation, in addition to catalyzing MoFe protein-independent substrate (CO) reduction and facilitating MoFe protein metallocluster biosynthesis. The precise role(s) of the Fe protein FeS cluster in some of these processes remains ill-defined. Herein, we report crystallographic data demonstrating ATP-dependent chalcogenide exchange at the FeS cluster of the nitrogenase Fe protein when potassium selenocyanate is used as the selenium source, an unexpected result as the Fe protein cluster is not traditionally perceived as a site of substrate binding within nitrogenase. The observed chalcogenide exchange illustrates that this FeS cluster is capable of core substitution reactions under certain conditions, adding to the Fe protein's repertoire of unique properties.
固氮酶 Fe 蛋白在固氮过程中介导 ATP 依赖性电子转移到固氮酶 MoFe 蛋白，此外还催化 MoFe 蛋白非依赖性底物（CO）还原并促进 MoFe 蛋白金属簇生物合成。Fe 蛋白 FeS 簇在这些过程中的一些精确作用仍未明确。在此，我们报告了晶体学数据，证明当使用硒氰酸钾作为硒源时，固氮酶 Fe 蛋白的 FeS 簇中存在 ATP 依赖性的类金属交换，这是一个意外的结果，因为传统上认为 Fe 蛋白簇不是固氮酶中底物结合的位点。观察到的类金属交换表明，该 FeS 簇在某些条件下能够进行核心取代反应，这增加了 Fe 蛋白独特性质的范围。
