Harnessing synthesis and biosynthesis to access complex molecules

酶化学是生产复杂分子的有力工具，如精细和研究化学品、营养药品和药品。酶用于研究和工业合成的一个主要限制是目前通过已知的酶反应可获得的化学多样性有限。这与合成有机化学形成鲜明对比。天然产物的结构表明，酶促反应可以获得令人难以置信的化学多样性。我的研究项目考察了负责天然产物生产的生物合成途径，以识别和利用能够扩展我们酶工具箱的酶。我们的长期目标是利用生物合成酶及其突变体在体内和体外快速生产各种分子。为了实现这一目标，我们的直接目标是开发新的催化剂，可以用于化学酶合成天然产物。天然产物全合成是新化学方法的严格试验场，新酶在这一领域的成功整合将促进其在研究和生产中的广泛应用。为了实现扩大可用酶促反应工具箱的长期目标，我们提出了三个短期目标。1)大环化生物催化剂的发展。大环化是合成中最具决定性的一步，可以决定任何合成路线的整体效率。目前还没有开发出合成这一关键官能团的生物催化剂。我们将描述和工程硫酯酶大环化广泛的底物，显著影响合成化学和酶学社区。2)聚酮类化合物的化学酶法全合成。天然产物全合成是新化学方法的严格试验场。利用来自多种生物合成途径的聚酮合成酶，我们将复杂的合成底物转化为海绵衍生的海洋天然产物neopeltolide。这种化学酶合成将是同类中的第一个，并证明了在复杂分子总合成的后期阶段使用聚酮合酶，转化复杂的聚酮合成。3)发现新的生物催化剂。为了更好地了解化学多样性，我们将从新发现的催化多种功能基团形成的生物合成途径中描述酶。这项工作将扩大我们对生物合成的理解，并增加酶促反应可获得的化学类型。

Enzymatic chemistry is a powerful tool for the production of complex molecules such as fine and research chemicals, nutraceuticals, and pharmaceuticals. A major limitation to the use of enzymes for research and industrial synthesis is the restricted chemical diversity currently accessible through known enzymatic reactions. This is in stark contrast to synthetic organic chemistry. The structures of natural products show that enzymatic reactions can access incredible chemical diversity. My research program examines the biosynthetic pathways responsible for natural product production to identify and harness enzymes capable of expanding our enzymatic toolbox. Our long term goal is to use biosynthetic enzymes and their mutants to enable rapid production of diverse molecules in vivo and in vitro. To achieve this our immediate goals are to developing new catalysts that can be used in chemoenzymatic synthesis of natural products. As natural product total synthesis is a rigorous testing ground for new chemical methodology, successful integration of new enzymes in this arena will facilitate their broader application in research and manufacturing. To meet our long-term goal of expanding the toolbox of available enzymatic reactions, we propose three short-term objectives. 1) Development of macrocyclization biocatalysts. Macrocyclization is the most decisive step of a synthesis and can define the overall efficiency of any synthetic route. No biocatalyst has been developed to synthesize this key functional group. We will characterize and engineer thioesterases to macrocyclize a broad range of substrates, significantly impacting the synthetic chemistry and enzymology communities. 2) The chemoenzymatic total synthesis of polyketides. Natural product total synthesis is a rigorous testing ground for new chemical methodologies. Using polyketide synthases from multiple biosynthetic pathways, we will convert a complex synthetic substrate into the sponge derived marine natural product neopeltolide. This chemoenzymatic synthesis will be the first of its kind and demonstrate of the use of polyketide synthases in the late stages of complex molecule total synthesis, transforming complex polyketide synthesis. 3) New biocatalyst discovery. To provide greater access to chemical diversity, we will characterize enzymes from newly discovered biosynthetic pathways that catalyze formation of diverse functional groups. This work will expand our understanding of biosynthesis and increase the type of chemistry accessible from enzymatic reactions.