Artificial metalloenzymes that contain protein-anchored synthetic catalysts are attracting increasing interest. An exciting, but still unrealized advantage of non-covalent anchoring is its potential for reversibility and thus component recycling. Here we present a siderophore–protein combination that enables strong but redox-reversible catalyst anchoring, as exemplified by an artificial transfer hydrogenase (ATHase). By linking the iron(iii)-binding siderophore azotochelin to an iridium-containing imine-reduction catalyst that produces racemic product in the absence of the protein CeuE, but a reproducible enantiomeric excess if protein bound, the assembly and reductively triggered disassembly of the ATHase was achieved. The crystal structure of the ATHase identified the residues involved in high-affinity binding and enantioselectivity. While in the presence of iron(iii), the azotochelin-based anchor binds CeuE with high affinity, and the reduction of the coordinated iron(iii) to iron(ii) triggers its dissociation from the protein. Thus, the assembly of the artificial enzyme can be controlled via the iron oxidation state.

包含蛋白质锚定的合成催化剂的人工金属酶正引起越来越多的兴趣。非共价锚固的一个令人兴奋但仍未实现的优势是其具有可逆性并因此具有组件回收的潜力。在这里，我们介绍了一种铁载体与蛋白质的结合体，该结合体能够实现牢固但氧化还原可逆的催化剂锚定，例如人工转移氢化酶（ATHase）。通过连接铁（iii）将铁载体偶氮螯合蛋白结合到含铱的亚胺还原催化剂上，该催化剂在不存在蛋白质CeuE的情况下产生外消旋产物，但是如果蛋白质结合，ATH酶的组装和还原触发的拆分，则可再现的对映体过量。ATHase的晶体结构确定了参与高亲和力结合和对映选择性的残基。当存在铁（iii）时，基于偶氮螯合蛋白的锚以高亲和力结合CeuE，并且配位铁（iii）还原为铁（ii）触发了其与蛋白质的解离。因此，可以通过铁的氧化状态来控制人造酶的组装。