Nitrogenases reduce N₂, the most abundant element in Earth's atmosphere that is otherwise resistant to chemical conversions due to its stable triple bond. Vanadium nitrogenase stands out in that it additionally processes carbon monoxide, a known inhibitor of the reduction of all substrates other than H⁺. The reduction of CO leads to the formation of hydrocarbon products, holding the potential for biotechnological applications in analogy to the industrial Fischer–Tropsch process. Here we report the most highly resolved structure of vanadium nitrogenase to date at 1.0 Å resolution, with CO bound to the active site cofactor after catalytic turnover. CO bridges iron ions Fe2 and Fe6, replacing sulfide S2B, in a binding mode that is in line with previous reports on the CO complex of molybdenum nitrogenase. We discuss the structural consequences of continued turnover when CO is removed, which involve the replacement of CO possibly by OH⁻, the movement of Q176^D and K361^D, the return of sulfide and the emergence of two additional water molecules that are absent in the CO‐bound state.

中文翻译：

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在原子分辨率下，CO与还原CO还原钒氮酶的FeV辅因子结合。

氮酶可以还原N ₂，N ₂是地球大气中最丰富的元素，由于其稳定的三键，因此可以抵抗化学转化。钒氮酶的突出之处在于它还可以处理一氧化碳，一氧化碳是除H ⁺以外的所有底物还原的已知抑制剂。二氧化碳的减少导致碳氢化合物产物的形成，与工业费-托工艺类似，具有生物技术应用的潜力。在这里，我们报道了迄今为止最高度解析的钒氮酶结构，分辨率为1.0Å，在催化转换后，CO与活性位点辅因子结合。CO以结合方式桥接铁离子Fe2和Fe6，取代了硫化物S2B，这与以前有关钼固氮酶CO复合物的报道相符。我们讨论时CO被删除持续成交的结构性影响，其通过OH可能涉及更换的CO ^-，Q176的运动^d和K361 ^d，硫化物的回流和另外两个在CO结合状态下不存在的水分子的出现。