High-throughput approaches in enzyme discovery and engineering

酶是非凡的生物催化剂——它们是细胞工厂的机器，是大自然经过亿万年的进化精心打造的。在自然界中，酶催化生物体内的化学反应，而在生物技术应用中，酶被从自然环境中提取出来，用于许多工业中重要的化学过程。由于工业生物催化中酶的使用条件和目的往往与它们进化的自然环境和功能完全不同，因此它们在这些过程中的性能还有很大的改进空间。酶在生物工业中的应用潜力通过酶工程的努力得到了极大的扩展，例如定向进化。我提出了一个研究计划，专注于酶生物催化剂的发现和工程，用于生产高价值生物活性化合物和生物可再生化学品，作为石油产品的替代品。这将通过最初针对两类酶来实现：糖基转移酶，将糖单元连接到天然产物支架上以产生生物活性的糖基化小分子；以及参与脂肪酸转化为碳氢化合物的脱羧酶，这些碳氢化合物可能被用来取代石化产品，作为燃料和化学基石。我们将开发方法，使我们不仅能够发现，而且能够设计产生这些有价值的化合物的酶。利用定向进化，我们将提高这些酶生物催化剂生产此类化合物的效率，并改变它们的特异性，以扩大它们可以生产的分子种类。生产可再生资源和高价值生物活性化学品的生物催化工具工程将具有显著的社会效益和经济效益。

Enzymes are extraordinary biocatalysts – they are the machinery of cell factories, crafted by Nature over aeons of evolution. In Nature, enzymes catalyze the chemical reactions within living organisms, whereas in biotechnological applications, they are taken out of their natural context and used for chemical processes that are important in many industries. Since enzymes in industrial biocatalysis are often used in conditions and for purposes quite different from the natural context and function for which they have evolved, there is much room to improve their performance in these processes. The potential of enzymes in bioindustrial applications is greatly expanded through enzyme engineering efforts, such as directed evolution. I propose a research program focused on the discovery and engineering of enzyme biocatalysts for the production of high-value bioactive compounds and of biorenewable chemicals as alternatives to petroleum products. This will be achieved by initially targeting two classes of enzymes: glycosyltransferases that attach sugar units onto natural product scaffolds to produce bioactive glycosylated small molecules; and decarboxylases involved in the conversion of fatty acids into hydrocarbons that can potentially be used to replace petrochemicals as fuels and chemical building blocks. We will develop methods that will enable us not only to discover, but to engineer the enzymes that produce these valuable compounds. Using directed evolution we will improve the efficiency of these enzyme biocatalysts in producing such compounds, and alter their specificity to expand the kinds of molecules that they can produce. The engineering of biocatalyst tools for producing renewable resources and high-value bioactive chemicals will be of significant social and economic benefit.