A structural unit found in the active site of some copper proteins, the histidine brace, is comprised of an N-terminal histidine that chelates a single copper ion through its amino terminus NH₂ and the π–N of its imidazole side chain. Coordination is completed by the τ-N of a further histidine side chain, to give an overall N₃ T-shaped coordination at the copper ion. The histidine brace appears in several proteins, including lytic polysaccharide monooxygenases LPMOs and particulate methane monooxygenases pMMOs, both of which catalyse the oxidation of substrates with strong C–H bonds (bond dissociation enthalpies ~100 kcal mol^–1). As such, the copper histidine brace is the focus of research aimed at understanding how nature catalyses the oxidation of unactivated C–H bonds. In this Perspective, we evaluate these studies, which further give bioinspired direction to coordination chemists in the design and preparation of small molecule copper oxidation catalysts.

在一些铜蛋白的活性位点中发现的结构单元，即组氨酸支架，由一个N端组氨酸组成，该组氨酸通过其氨基末端NH ₂和其咪唑侧链的π–N螯合单个铜离子。通过另一个组氨酸侧链的τ-N完成配位，从而在铜离子上产生整体N ₃ T形配位。组氨酸支架出现在几种蛋白质中，包括溶解性多糖单加氧酶LPMO和颗粒甲烷单加氧酶pMMO，它们都催化具有强C–H键的底物的氧化（键解离焓为〜100 kcal mol ^–1。）。因此，组氨酸铜支架是研究的重点，旨在了解自然界如何催化未活化的C–H键的氧化。在此观点下，我们评估了这些研究，进一步为配位化学家设计和制备小分子铜氧化催化剂提供了生物学启发的方向。