美国加州理工学院Arnold, Frances H.团队报道了双功能酶催化用于对映选择性碳氮键的形成。相关研究成果发表在2021年10月18日出版的《自然—化学》。

手性胺可以通过使用两种催化剂系统将卡宾插入N–H键来制备，这两种催化剂系统结合了基于过渡金属的卡宾转移催化剂和手性质子转移催化剂来实施立体控制。血红素蛋白可以影响卡宾N–H的插入，但在充满质子源的活性部位进行不对称质子化是一个挑战。

该文中，研究人员描述了催化卡宾N–H插入以制备具有高活性和对映选择性的生物相关α-氨基内酯的工程化细胞色素P450酶（总转化率高达32100，产率>99%，e.e.为98%）。这些酶作为双功能催化剂，诱导卡宾转移并促进随后的质子转移，在单一活性部位具有良好的立体选择性。计算研究揭示了该新的自然酶反应的详细机制，并解释了活性位点残基如何加速这种转化并提供立体控制。

附：英文原文

Title: Dual-function enzyme catalysis for enantioselective carbon–nitrogen bond formation

Author: Liu, Zhen, Calv-Tusell, Carla, Zhou, Andrew Z., Chen, Kai, Garcia-Borrs, Marc, Arnold, Frances H.

Issue&Volume: 2021-10-18

Abstract: Chiral amines can be made by insertion of a carbene into an N–H bond using two-catalyst systems that combine a transition metal-based carbene-transfer catalyst and a chiral proton-transfer catalyst to enforce stereocontrol. Haem proteins can effect carbene N–H insertion, but asymmetric protonation in an active site replete with proton sources is challenging. Here we describe engineered cytochrome P450 enzymes that catalyse carbene N–H insertion to prepare biologically relevant α-amino lactones with high activity and enantioselectivity (up to 32,100 total turnovers, >99% yield and 98%e.e.). These enzymes serve as dual-function catalysts, inducing carbene transfer and promoting the subsequent proton transfer with excellent stereoselectivity in a single active site. Computational studies uncover the detailed mechanism of this new-to-nature enzymatic reaction and explain how active-site residues accelerate this transformation and provide stereocontrol.

DOI: 10.1038/s41557-021-00794-z

Source: https://www.nature.com/articles/s41557-021-00794-z