Investigating Diels-Alderases for the Biocatalytic Synthesis of Abyssomicin 2 and Neoabyssomicin A

目前估计，每年有70万人死于耐药细菌感染。从微生物中分离的聚酮衍生的天然产物是发现新的抗菌、抗肿瘤和抗真菌化合物的丰富来源。鉴定这些分子对于对抗抗菌素耐药性的上升至关重要。该项目的总体目标是充分了解聚酮化合物在自然界中是如何组装的，以允许合理设计生物合成途径，从而以克级数量有效且廉价地获得新型生物活性分子。Diels-Alder反应是合成化学中最强有力的转化反应之一，由于其精确的区域和立体选择性，因此能够促进这些反应的新催化剂具有重要价值。酶由于其固有的“绿色”性质而成为开发手性催化剂的有吸引力的候选者。该项目将专注于真正的天然Diels-Alderase，AbmU，已被证明在深海霉素2和新深海霉素A的生物合成中催化线性底物的环化以形成螺内酯核心。生物合成途径的后期定制步骤将通过进行新深海霉素A的首次全合成来研究。为了使AbmU作为生物催化剂的广泛使用，其底物范围，催化效率和可扩展性将使用有机合成和合成生物学的组合进行探索。

It is currently estimated that 700,000 people die from resistant bacterial infections each year. Polyketide-derived natural products isolated from microorganisms are a rich source of discovery for new antibacterial, antitumour and antifungal compounds. The identification of such molecules is of the utmost importance to combat the rise in antimicrobial resistance. The overall aim of this project is to fully understand how polyketides are assembled in nature to allow rational engineering of the biosynthetic pathway to access novel bioactive molecules efficiently and inexpensively in gram-scale quantities. Diels-Alder reactions are amongst the most powerful transformations in synthetic chemistry owing to their exquisite regio- and stereoselectivity, so new catalysts able to promote these reactions would have major value. Enzymes are attractive candidates for development as chiral catalysts owing to their inherently "green" nature. This project will focus on the bona fide natural Diels-Alderase, AbmU, which has been shown to catalyse the cyclisation of a linear substrate to form the spirotetronate core in the biosynthesis of abyssomicin 2 and neoabyssomicin A. The later tailoring steps of the biosynthetic pathway will be investigated by undertaking the first total synthesis of neoabyssomicin A. To enable the widespread use of AbmU as a biocatalyst, its substrate scope, catalytic efficiency and scalability will be explored using a combination of organic synthesis and synthetic biology.