Aryl ethers are ubiquitous protecting groups of alcohols and amines in organic chemistry. This is owed to the simplicity of their appendage to molecules and the robust protection afforded. However, aryl ethers and amines can be challenging to cleave, often requiring harsh and unselective reductive conditions. We report the structure-based engineering of a promiscuous, ether-cleaving vanillyl alcohol oxidase-type biocatalyst for activity on a wide range of para-hydroxy benzyl ethers. Two superior quadruple mutants are identified with improved kinetics and substrate scope. One evolved variant and two predecessors are crystallized, and their structures resolved to 2.8–1.5 Å, revealing a significant increase in the volume and flexibility of the active site cavity. To illustrate the potential usefulness of the engineered biocatalysts, one is later coupled with another biocatalyst in a cascade reaction to catalyze the selective cleavage of an uncommon aryl ether protecting group, para-acyloxy benzyl ethers, in good yield and under mild conditions.

中文翻译：

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对乙酰氧基苄醚的生物催化裂解：在保护基团化学中的应用


芳基醚是有机化学中无处不在的醇和胺保护基团。这要归功于它们对分子的简单附属和提供的强大保护。然而，芳基醚和胺可能难以裂解，通常需要苛刻和非选择性的还原条件。我们报道了一种混杂的、醚裂解的香草醇氧化酶型生物催化剂的基于结构的工程设计，该生物催化剂对多种对羟基苄基醚具有活性。鉴定出两个优越的四重突变体，动力学和底物范围得到改善。一个进化变体和两个前体结晶，其结构分离为 2.8–1.5 Å，揭示了活性位点腔的体积和柔韧性显著增加。为了说明工程生物催化剂的潜在用途，稍后在级联反应中将一种生物催化剂与另一种生物催化剂偶联，以催化不常见的芳基醚保护基团对酰氧基苄基醚的选择性裂解，产量高，条件温和。