Laccases are enzymes that catalyze the oxidation of a wide range of organic and inorganic substrates accompanied by the reduction of molecular oxygen to water. Here, a subatomic resolution X‐ray crystallographic study of the mechanism of inhibition of the laccase from the basidiomycete fungus Steccherinum murashkinskyi by chloride and fluoride ions is presented. Three series of X‐ray diffraction data sets were collected with increasing doses of absorbed X‐ray radiation from a native S. murashkinskyi laccase crystal and from crystals of complexes of the laccase with chloride and fluoride ions. The data for the native laccase crystal confirmed the previously deduced enzymatic mechanism of molecular oxygen reduction. The structures of the complexes allowed the localization of chloride and fluoride ions in the channel near the T2 copper ion. These ions replace the oxygen ligand of the T2 copper ion in this channel and can play the role of this ligand in the enzymatic reaction. As follows from analysis of the structures from the increasing dose series, the inhibition of laccases by chloride and fluoride anions can be explained by the fact that the binding of these negatively charged ions at the position of the oxygen ligand of the T2 copper ion impedes the reduction of the T2 copper ion.

中文翻译：

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使用单晶串联晶体学研究氯离子和氟离子抑制漆酶的亚原子拆分：洞悉酶促反应机理。

漆酶是催化广泛的有机和无机底物氧化并伴随着分子氧还原为水的酶。在这里，提出了一个亚原子分辨率的X射线晶体学研究，该研究通过氯离子和氟离子抑制了担子菌真菌Steakcherinum murashkinskyi中的漆酶。收集了三个系列的X射线衍射数据集，它们的剂量与来自本地S. murashkinskyi的X射线辐射的吸收剂量有关漆酶晶体以及漆酶与氯离子和氟离子的络合物晶体。天然漆酶晶体的数据证实了先前推导的分子氧还原的酶促机理。配合物的结构允许氯离子和氟离子在T2铜离子附近的通道中定位。这些离子在此通道中替代T2铜离子的氧配体，并可以在酶促反应中发挥该配体的作用。从增加剂量系列的结构分析可以看出，氯和氟阴离子对漆酶的抑制作用可以通过以下事实来解释：这些带负电的离子在T2铜离子的氧配体位置上的结合会阻碍还原T2铜离子。