Chemogenetic Evolution of Diversified Photoenzymes for Enantioselective [2 + 2] Cycloadditions in Whole Cells

作者：Juan Guo, Junyi Qian, Dai-Hong Cai, Jianjian Huang, Xinjie Yang, Ningning Sun, Junshuai Zhang, Tengfei Pang, Weining Zhao, Guojiao Wu, Xi Chen, Fangrui Zhong, Yuzhou Wu · 发表于：Journal of the American Chemical Society · 年份：2024 · DOI：10.1021/jacs.4c03087 · 被引用次数：53 · 研究领域：Radical Photochemical Reactions、Catalytic C–H Functionalization Methods、CO2 Reduction Techniques and Catalysts

Artificial photoenzymes with novel catalytic modes not found in nature are in high demand; yet, they also present significant challenges in the field of biocatalysis. In this study, a chemogenetic modification strategy is developed to facilitate the rapid diversification of photoenzymes. This strategy integrates site-specific chemical conjugation of various artificial photosensitizers into natural protein cavities and the iterative mutagenesis in cell lysates. Through rounds of directed evolution, prominent visible-light-activatable photoenzyme variants were developed, featuring a thioxanthone chromophore. They successfully enabled the enantioselective [2 + 2] photocycloaddition of 2-carboxamide indoles, a class of UV-sensitive substrates that are traditionally challenging for known photoenzymes. Furthermore, the versatility of this photoenzyme is demonstrated in enantioselective whole-cell photobiocatalysis, enabling the efficient synthesis of enantioenriched cyclobutane-fused indoline tetracycles. These findings significantly expand the photophysical properties of artificial photoenzymes, a critical factor in enhancing their potential for harnessing excited-state reactivity in stereoselective transformations.