Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA, 93106, USA.
Chembiochem. 2023 Dec 1;24(23):e202300561. doi: 10.1002/cbic.202300561. Epub 2023 Oct 16.
α-Deuterated amino acids are valuable building blocks for developing deuterated drugs, and are important tools for studying biological systems. Biocatalytic deuteration represents an attractive strategy to directly access enantiopure α-deuterated amino acids. Here, we show that a PLP-dependent Mannich cyclase, LolT, involved in the biosynthesis of loline alkaloids, is capable of deuterating a diverse range of L-amino acids, including basic and acidic, nonpolar and polar, aliphatic and aromatic amino acids. Furthermore, complete deuteration of many amino acids can be achieved within minutes with exquisite control on the site- and stereoselectivity. During the course of this investigation, we also unexpectedly discovered that LolT exhibits β-elimination activity with L-cystine and O-acetyl-L-serine, confirming our previous hypothesis based on structural and phylogenetic analysis that LolT, a Cα-C bond forming enzyme, is evolved from a primordial Cβ-S lyase family. Overall, our study demonstrates that LolT is an extremely versatile biocatalyst, and can be used for not only heterocyclic quaternary amino acid biosynthesis, but also biocatalytic amino acid deuteration.
α-氘代氨基酸是开发氘代药物的有价值的构建模块，也是研究生物系统的重要工具。生物催化氘代反应代表了一种直接获得对映纯α-氘代氨基酸的有吸引力的策略。在这里，我们表明参与洛林生物碱生物合成的依赖 PLP 的 Mannich 环化酶 LolT 能够氘代多种 L-氨基酸，包括碱性和酸性、非极性和极性、脂肪族和芳香族氨基酸。此外，许多氨基酸可以在几分钟内完成完全氘代，并且对位点和立体选择性具有极好的控制。在进行这项研究的过程中，我们还意外地发现 LolT 对 L-胱氨酸和 O-乙酰-L-丝氨酸表现出β-消除活性，这证实了我们之前基于结构和系统发育分析的假设，即 LolT 是一种 Cα-C 键形成酶，是从原始的 Cβ-S 裂合酶家族进化而来的。总的来说，我们的研究表明 LolT 是一种极其多功能的生物催化剂，不仅可用于杂环季铵氨基酸的生物合成，还可用于生物催化氨基酸氘代。
