Engineering Metallo-Enzyme Environments for Selective C-H Activation Chemistry

一个多用途催化平台的可用来精确定位复杂有机分子中的单个C-H键并使其功能化，将彻底改变我们的合成策略，导致通往高价值化学品的路线简化，并支持更绿色的化学工业的发展。尽管使用小的过渡金属络合物可以实现大量的C-H官能化，但中心选择性通常由底物的特性决定，而不是由催化剂决定。实现更理想的“催化剂控制”转化的一般方法需要催化剂中的分子识别元件，这些元件：a)允许精确的底物取向，b)可以调节以改变选择性。原则上，这些要求可以由蛋白质催化剂完美地解决，这些催化剂可以很容易地通过实验室进化来适应。然而，酶工程的策略目前仅限于自然界的二十个氨基酸字母表，这严重限制了我们理解生物催化C-H激活过程的能力，并进一步限制了蛋白质中可获得的金属配位环境的范围，从而限制了催化活性。在这个学生中，我们将利用我们实验室提供的先进蛋白质工程技术，在选定的酶支架上安装“化学编程”的配体和/或贵金属辅助因子，为直接探索和调整生物催化C-H功能化机制开辟了新的途径。随后，我们将使用现代超高通量筛选方法，通过具有扩展遗传密码的定向进化来系统地优化所得到的C-H活化催化剂，从而提供具有增强选择性/活性特征的生物催化剂。这种方法将小分子催化剂可获得的广泛的C-H官能化与蛋白质提供的选择性的精确控制相结合，因此将对整个化学工业的可持续制造产生重大影响。该项目与EPSRC的“催化”和“化学生物学和生物化学”研究领域完美结合。

The availability of a versatile catalytic platform to precisely target and functionalize individual C-H bonds in complex organic molecules would revolutionize our synthetic strategies, leading to streamlined routes to high value chemicals and supporting the development of a 'greener' chemical industry. Although an impressive range of C-H functionalizations can be achieved with small transition metal complexes, site selectivity is often determined by features of the substrate, and not by the catalyst. A general approach to achieve the more aspirational 'catalyst controlled' transformations requires molecular recognition elements within the catalyst which: a) allow precise substrate orientation and b) can be tuned to alter selectivity. In principle, these requirements could be perfectly addressed by protein catalysts which can be readily adapted via laboratory evolution. However, enzyme engineering strategies are currently limited to Nature's twenty amino acid alphabet which severely restricts our ability to understand biocatalytic C-H activation processes, and furthermore limits the range of metal co-ordination environments, and thus catalytic activities, that are accessible within proteins.In this studentship we will exploit advanced protein engineering technology available in our laboratory to install 'chemically programmed' ligands and/or noble metal co-factors into selected enzyme scaffolds, opening new avenues to directly probe and tune biocatalytic C-H functionalization mechanisms. We will subsequently demonstrate that the resulting C-H activation catalysts can be systematically optimized via directed evolution with an expanded genetic code using modern ultra-high throughput screening methods, affording biocatalysts with augmented selectivity/activity profiles. This approach merges the broad range of C-H functionalizations accessible with small molecule catalysts with precise control of selectivity provided by proteins, and thus will have major impacts for sustainable manufacturing across the chemical industry.This project is perfectly aligned with the 'Catalysis' and 'Chemical Biology and Biological Chemistry' EPSRC research areas.