荷兰格罗宁根大学Gerard Roelfes研究小组近日取得一项新成果。经过不懈努力，他们在设计的酶中实现了硼催化作用。2024年5月8日出版的《自然》发表了这项成果。

在该研究中，该研究组提出了一种完全由基因编码的含硼酸设计酶，其有机催化活性是天然或工程生物催化剂无法实现的。这种硼酶通过肟形成催化羟基酮的动力学分解，其中与蛋白质支架的关键相互作用有助于催化。定向进化运动导致了对几种不同底物具有天然酶样对映体选择性的变体。

通过X射线晶体学、高分辨率质谱分析(HRMS)和¹¹B核磁共振谱分析证实了硼酶的独特活化模式。他们的研究表明，基因密码扩展可以被用在创造可进化的对映选择性酶，这种酶依赖于异种催化部分如硼酸，并实现通过天然酶或工程酶的催化无法达到的反应机制。

据悉，酶在提高化工生产的环保性和效率方面发挥着越来越重要的作用，但由于酶的反应机理范围相对狭窄，其应用的多样性严重落后于化学催化剂。含有非生物功能的酶的创造促进了自然界经典之外的反应机制，并为完全可编程的生物催化铺平了道路。

附：英文原文

Title: Boron catalysis in a designer enzyme

Author: Longwitz, Lars, Leveson-Gower, Reuben B., Rozeboom, Henritte J., Thunnissen, Andy-Mark W. H., Roelfes, Gerard

Issue&Volume: 2024-05-08

Abstract: Enzymes play an increasingly important role in improving the benignity and efficiency of chemical production, yet the diversity of their applications lags heavily behind chemical catalysts as a result of the relatively narrow range of reaction mechanisms of enzymes. The creation of enzymes containing non-biological functionalities facilitates reaction mechanisms outside nature’s canon and paves the way towards fully programmable biocatalysis1,2,3. Here we present a completely genetically encoded boronic-acid-containing designer enzyme with organocatalytic reactivity not achievable with natural or engineered biocatalysts4,5. This boron enzyme catalyses the kinetic resolution of hydroxyketones by oxime formation, in which crucial interactions with the protein scaffold assist in the catalysis. A directed evolution campaign led to a variant with natural-enzyme-like enantioselectivities for several different substrates. The unique activation mode of the boron enzyme was confirmed using X-ray crystallography, high-resolution mass spectrometry (HRMS) and 11B NMR spectroscopy. Our study demonstrates that genetic-code expansion can be used to create evolvable enantioselective enzymes that rely on xenobiotic catalytic moieties such as boronic acids and access reaction mechanisms not reachable through catalytic promiscuity of natural or engineered enzymes.

DOI: 10.1038/s41586-024-07391-3

Source: https://www.nature.com/articles/s41586-024-07391-3