Understanding the specificity and non-native catalytic activity of PLP-dependent enzymes

项目摘要 PLP依赖性酶是最通用的生物催化剂之一，并催化多种多样的生物降解。 化学转化它们广泛存在于自然界中，在新陈代谢中起着关键作用， 细胞过程因此，研究PLP酶对我们了解生物学和开发 治疗学由于其精致和多功能的催化活性，PLP依赖性酶也是 卓越的生物催化剂，以构建多种结构复杂和生物活性的天然产品; 非规范氨基酸和手性胺不对称合成不可缺少的生物催化工具 大药厂然而，尽管迄今为止表征了大量的PLP依赖性酶， 预测、操纵和驾驭其活动的能力仍然很有限。这项研究计划希望 通过整合发现、机理研究和生物催化应用来填补知识空白， 系统全面地研究了四种类型碳-碳（C-C）键形成和断裂PLP 酶，包括我们最近发现的PLP依赖性曼尼希环化酶。这些酶代表了 PLP酶学的前沿，因为它们不寻常的活性，补充现有的合成效用， 生物催化剂，以及与充分表征的PLP酶家族的意想不到的进化关系。所有拟议 我们实验室收集的初步数据有力地支持了这些目标。我们的首要目标是了解 化学和底物特异性，并利用这种理解来揭示以前未知的功能 的PLP依赖性酶，并探索其非天然催化效用。最终，拟议的研究将 扩大我们对PLP酶学的机械理解，阐明代谢的新观点，并提供新的 氨基酸生物合成的生物催化工具。

Project Summary PLP-dependent enzymes are one of the most versatile biocatalysts and catalyze a diverse range of chemical transformations. They are widespread in nature and play critical roles in metabolism and numerous cellular processes. Studying PLP enzymes is hence important for us to understand biology and develop therapeutics. Because of their exquisite and versatile catalytic activity, PLP-dependent enzymes are also remarkable biocatalysts to build diverse structurally complex and bioactive natural products; and are indispensable biocatalytic tools for asymmetric synthesis of noncanonical amino acids and chiral amine pharmaceuticals. However, despite the vast number of PLP-dependent enzymes characterized to date, our abilities to predict, manipulate, and harness their activities are still largely limited. This research program desires to fill the knowledge gap by integrating discovery, mechanistic investigation, and biocatalytic application to systematically and comprehensively study four types of carbon-carbon (C-C) bond forming and cleaving PLP enzymes, including our recently discovered PLP-dependent Mannich cyclase. These enzymes represent the frontier of PLP enzymology because of their unusual activity, complementary synthetic utility to existing biocatalysts, and unexpected evolutionary relationship with well-characterized PLP enzyme family. All proposed aims are supported by strong preliminary data gathered in our laboratory. Our overarching goal is to understand the chemical and substrate specificity and leverage this understanding to uncover previously unknown functions of PLP-dependent enzymes and explore their non-native catalytic utility. Ultimately, the proposed research will expand our mechanistic understanding on PLP enzymology, shed new light on metabolism, and provide novel biocatalytic tools for amino acid biosynthesis.