Engineering Water Capture in Terpene Synthases

酶是一种了不起的生物分子，能够在生命系统中发现的温和条件下进行复杂的化学反应，具有非凡的精确性。萜烯脱氢酶是催化仅少量底物转化为称为萜类化合物的无数不同烃产物的酶，萜类化合物的结构形成最大组天然产物的化学基础。许多萜类化合物都有有益的应用，如抗癌药物紫杉醇，抗疟疾药物青蒿素和所谓的化学信息素，可以作为驱虫剂。这些是基于倍半萜烯，萜类家族的一个子集，含有15个碳原子，并衍生自相同的分子，法呢基二磷酸（FDP）。天然倍半萜烯脱氢酶可以从FDP产生超过300种不同的烃支架。无论这些支架是否结合水（通过羟基化或“水捕获”）都会影响其生物活性和用途。在过去几十年中进行的结构和机械工作表明，这些酶共享一个三维折叠，并使用类似的化学策略来实现FDP转化为产品。虽然已经取得了很大的进展，破译的生化细节，我们的知识是不够完整，有预测能力，使一个合理的方法可以用来转换的'水捕获'行为的萜烯脱氢酶在一个有针对性的方式。拟议的研究，这是基于以前的工作和申请人的互补经验的坚实基础，将汇集酶学家，计算生物化学家和结构生物学家，以产生在萜烯脱氢酶的“水捕获”机制的深入了解。然后，这种理解将用于合理地改变示例酶中的“水捕获”行为，这将导致具有潜在有益特性的新型萜类化合物产品。最先进的计算和实验工作的结合对于实现这一目标至关重要。通过使用实验数据，例如通过X射线晶体学获得的结构，计算建模提供了通过实验室实验无法获得的独特细节，这反过来又可用于预测氨基酸变化的影响。这些预测随后需要实验验证。通过这种结合的方法，我们将详细地发现酶的结构和流动性如何影响反应结果。一旦成功改变水捕获行为已经实现，我们将开发通用的，精简的协议，可以应用于其他萜烯脱氢酶。因此，这些方案将允许合理地修饰有效的生物催化剂，以获得具有所需性质的特定萜类化合物产物，例如开发新药或驱虫剂。

Enzymes are remarkable biomolecules that are able to make complicated chemical reactions occur under the mild conditions found in living systems, with remarkable precision. Terpene synthases are enzymes that catalyze the conversion of only a small number of substrates to a myriad of different hydrocarbon products called terpenoids, structures that form the chemical basis of the largest group of natural products. Many terpenoids have beneficial applications, such as the anti-cancer drug taxol, the anti-malaria drug artemisinin and so-called semiochemicals that can act as insect repellents. These are based on sesquiterpenes, a subset of the terpenoid family that contain 15 carbon atoms and derive from the same molecule, farnesyl diphosphate (FDP). Natural sesquiterpene synthases can generate more than 300 different hydrocarbon scaffolds from FDP. Whether or not these scaffolds incorporate water (through hydroxylation, or 'water capture') affects their biological activity and use. Structural and mechanistic work performed over the last decades has revealed that these enzymes share a three-dimensional fold and use similar chemical strategies to achieve the transformation of FDP into products. While much progress has been made to decipher the biochemical details, our knowledge is not complete enough to have predictive power so that a rational approach could be used to convert the 'water capture' behaviour of terpene synthases in a targeted fashion. The proposed research, which is based on a solid foundation of previous work and the complimentary experience of the applicants, will bring together enzymologists, computational biochemists and structural biologists to generate in-depth understanding of the mechanisms of 'water capture' in terpene synthases. This understanding will then be used to rationally change 'water capture' behaviour in example enzymes, which will lead to novel terpenoid products with potential beneficial properties. The combination of state-of-the-art computational and experimental work is crucial for achieving this. By using experimental data, such as structures obtained through X-ray crystallography, computational modelling offers unique detail not accessible through laboratory experiments, which in turn can be used to predict the effect of amino acid changes. These predictions subsequently need experimental validation. Through this combined approach we will discover in great detail how enzyme structure and mobility affect the reaction outcome. Once successful alteration of water capture behaviour has been achieved, we will develop general, streamlined protocols that can be applied to other terpene synthases. These protocols will therefore allow rational modification of efficient biocatalysts to obtain specific terpenoid products with desired properties, e.g. to develop new drugs or insect repellents.