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

一种多功能催化平台的可用性，以精确地靶向和功能化复杂有机分子中的单个C-H键，将彻底改变我们的合成策略，从而简化高价值化学品的路线，并支持“绿色”化学工业的发展。虽然可以用小的过渡金属络合物实现令人印象深刻的C-H官能化范围，但位点选择性通常由基底的特征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内的分子识别元件，其：a）允许精确的底物取向和B）可以被调节以改变选择性。原则上，这些要求可以通过蛋白质催化剂完美地解决，这些蛋白质催化剂可以通过实验室进化容易地适应。然而，酶工程策略目前仅限于自然界的20个氨基酸字母表，这严重限制了我们理解生物催化C-H活化过程的能力，并且进一步限制了金属配位环境的范围，从而限制了催化活性，在这个学生项目中，我们将利用我们实验室现有的先进蛋白质工程技术来安装“化学编程”配体。和/或贵金属辅因子到所选的酶支架中，开辟了直接探测和调节生物催化C-H官能化机制的新途径。我们随后将证明，所得的C-H活化催化剂可以通过定向进化与扩展的遗传密码，使用现代超高通量筛选方法进行系统优化，提供具有增强的选择性/活性概况的生物催化剂。该方法将小分子催化剂可实现的广泛的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”研究领域完全一致。

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.