Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States.
Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Carrer Maria Aurèlia Capmany 69, 17003 Girona, Spain.
J Am Chem Soc. 2021 May 12;143(18):7114-7123. doi: 10.1021/jacs.1c02146. Epub 2021 Apr 28.
A cytochrome heme protein was recently engineered to catalyze the formation of carbon-silicon bonds via carbene insertion into Si-H bonds, a reaction that was not previously known to be catalyzed by a protein. High chemoselectivity toward C-Si bond formation over competing C-N bond formation was achieved, although this trait was not screened for during directed evolution. Using computational and experimental tools, we now establish that activity and chemoselectivity are modulated by conformational dynamics of a protein loop that covers the substrate access to the iron-carbene active species. Mutagenesis of residues computationally predicted to control the loop conformation altered the protein's chemoselectivity from preferred silylation to preferred amination of a substrate containing both N-H and Si-H functionalities. We demonstrate that information on protein structure and conformational dynamics, combined with knowledge of mechanism, leads to understanding of how non-natural and selective chemical transformations can be introduced into the biological world.
最近，人们对细胞色素血红素蛋白进行了工程设计，使其能够通过卡宾插入 Si-H 键催化碳-硅键的形成，这是一种以前未知的由蛋白质催化的反应。尽管在定向进化过程中没有筛选高化学选择性的 C-Si 键形成，但还是实现了对竞争的 C-N 键形成的高化学选择性。使用计算和实验工具，我们现在确定，蛋白质环的构象动力学调节了活性和化学选择性，该环覆盖了底物进入铁-卡宾活性物种的通道。计算预测控制环构象的残基的突变改变了蛋白质的化学选择性，使含有 N-H 和 Si-H 官能团的底物由优先的硅烷化转变为优先的氨化。我们证明，有关蛋白质结构和构象动力学的信息，结合对机制的了解，可以深入了解如何将非天然和选择性的化学转化引入生物世界。
