The active site of [FeFe] hydrogenase, the H-cluster, consists of a canonical [4Fe–4S]_H subcluster linked to a unique binuclear [2Fe]_H subcluster containing three CO, two CN⁻ and a bridging azadithiolate (adt, NH(CH₂S⁻)₂) ligand. While it is known that all five diatomic ligands are derived from tyrosine, there has been little knowledge as to the formation and installation of the adt ligand. Here, by using a combination of a cell-free in vitro maturation approach with pulse electronic paramagnetic resonance spectroscopy, we discover that serine donates the nitrogen atom and the CH₂ group to the assembly of the adt ligand. More specifically, both CH₂ groups in adt are sourced from the C3 methylene of serine.

中文翻译：

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丝氨酸是体外组装的[FeFe]氢化酶H簇的NH（CH2）2桥头部分的分子来源

的[FEFE]氢化，该H-簇中，活性位点由一个典型的[的4Fe-4S] _ħ子集群链接到一个独特的双核的[2Fe] _ħ含有三个CO，2 CN子群集^-和桥接azadithiolate（ADT，NH （CH ₂小号^- ）₂）的配体。虽然已知所有五个双原子配体均衍生自酪氨酸，但对adt配体的形成和安装了解甚少。在这里，通过结合使用无细胞体外成熟方法和脉冲电子顺磁共振波谱，我们发现丝氨酸提供了氮原子和CH ₂组到adt配体的组装。更具体地，adt中的两个CH ₂基团均来自丝氨酸的C 3亚甲基。