In December 2019, the first cases of infection with a novel coronavirus, SARS-CoV-2, were diagnosed. Currently, there is no effective antiviral treatment for COVID-19. To address this emerging problem, we focused on the SARS-CoV-2 main protease that constitutes one of the most attractive antiviral drug targets. We have synthesized a combinatorial library of fluorogenic substrates with glutamine in the P1 position. We used it to determine the substrate preferences of the SARS-CoV and SARS-CoV-2 main proteases. On the basis of these findings, we designed and synthesized a potent SARS-CoV-2 inhibitor (Ac-Abu-dTyr-Leu-Gln-VS, half-maximal effective concentration of 3.7 µM) and two activity-based probes, for one of which we determined the crystal structure of its complex with the SARS-CoV-2 M^pro. We visualized active SARS-CoV-2 M^pro in nasopharyngeal epithelial cells of patients suffering from COVID-19 infection. The results of our work provide a structural framework for the design of inhibitors as antiviral agents and/or diagnostic tests.

2019 年 12 月，确诊了首例新型冠状病毒 SARS-CoV-2 感染病例。目前，没有针对 COVID-19 的有效抗病毒治疗方法。为了解决这个新出现的问题，我们专注于 SARS-CoV-2 主蛋白酶，它是最具吸引力的抗病毒药物靶点之一。我们已经合成了一个在 P1 位置具有谷氨酰胺的荧光底物组合文库。我们用它来确定 SARS-CoV 和 SARS-CoV-2 主要蛋白酶的底物偏好。在这些发现的基础上，我们设计并合成了一种有效的SARS-CoV的-2抑制剂（AC-Abu- d的Tyr-LEU-GLN-VS，3.7μM的半数最大有效浓度）和两个基于活动的探针，用于其中之一我们确定了其与 SARS-CoV-2 M ^pro复合物的晶体结构. 我们在 COVID-19 感染患者的鼻咽上皮细胞中观察到活性 SARS-CoV-2 M ^pro。我们的工作结果为设计抑制剂作为抗病毒剂和/或诊断测试提供了结构框架。