Expanding the Enzyme Repertoire by Evolution and Engineering

创造新的酶(加速化学反应的蛋白质)是一个巨大的挑战，几乎没有有效的设计策略。然而，大自然经常创造新的酶，例如当需要酶来降解人造化学物质并将其用作营养源时。该项目将开发一种基于对酶的化学和自然进化的基本了解来创造新酶的策略。该项目将探索自然产生的酶的范围可以扩大到什么程度，以提供新的化学成分，并具有极大的潜力，有助于提高化工和制药行业的竞争力。该项目将提供跨学科培训和准备，帮助研究生和博士后研究员在快速变化的学术和专业环境中发展职业生涯。该项目扩展了一个概念验证演示，证明细胞色素P450的催化功能可以适应合成前体到新的活性中间体，这是由于酶的多功能铁-血红素假体基团。这些新的活性中间体开启了一系列酶催化反应的可能性，这些反应在自然界中是未知的。该项目将探索如何充分优化非自然反应动力学，以及如何将新反应结合到体内和体外的代谢途径中。定向进化将被用来提高突变细胞色素P450的表达，改善反应动力学，并扰乱电子转移速度以提高硝烯转移反应的选择性。对所有进化中间体的‘化石记录’进行详细的动力学、结构和生物化学研究，将为实现新的胺化活动的分子途径提供基本的见解。特别关注分子间的烯烃叠氮化和C-H胺化利用了定向进化方面的专业知识，以及对P450‘S天然化学和所需的新酶活性之间的机理相似性的理解。该奖项由分子和细胞生物科学部的系统和合成生物学计划、化学、生物工程、环境和运输系统司的生命过程化学计划和生物催化计划联合资助。

Creating new enzymes (proteins that speed up chemical reactions) is a formidable challenge for which few effective design strategies exist. However, nature frequently creates new enzymes, for example when enzymes are needed to degrade man-made chemicals and to use these as a nutrient source. This project will develop a strategy for creating new enzymes based on a fundamental understanding of both chemistry and of the natural evolution of enzymes. The project will probe the degree to which the range of naturally occurring enzymes can be expanded to deliver novel chemistries and has significant potential to contribute to the competitiveness of the chemical and pharmaceutical industries. The project will provide interdisciplinary training and preparation that will help graduate students and postdoctoral fellows to develop careers in a rapidly changing academic and professional environment. The project extends a proof-of-concept demonstration that the catalytic functions of cytochrome P450s can accommodate synthetic precursors to new reactive intermediates as a result of the enzymes' versatile iron-heme prosthetic group. These new reactive intermediates open up the possibility of an array of enzyme-catalyzed reactions that are not known in nature. The project will explore how the non-natural reaction kinetics can be fully optimized and how the new reactions can be incorporated into metabolic pathways using a combination of in vivo and in vitro approaches. Directed evolution will be used to improve the expression of mutated cytochrome P450s, improve reaction kinetics, and perturb the rate of electron transfer for improved nitrene-transfer reaction selectivity. Detailed kinetic, structural and biochemical studies of the 'fossil record' of all evolutionary intermediates will provide fundamental insights into the molecular pathways by which new amination activities can be realized. The specific focus on intermolecular alkene aziridination and C-H amination draws on expertise in directed evolution and understanding of mechanistic similarities between P450's native chemistry and the desired new enzyme activities.This award is funded jointly by the Systems and Synthetic Biology Program, Division of Molecular and Cellular Biosciences; the Chemistry of Life Processes Program, Division of Chemistry, and the Biocatalysis Program of the Chemical, Bioengineering, Environmental, and Transport Systems Division.