Structural Basis for coronaviral main proteases Inhibition by a 3CL Protease Inhibitor- GC376

• Published in: Journal of molecular biology p. 168474
• Main Authors: Lin, Cheng, Zhu, Zhimin, Jiang, Haihai, Zou, Xiaofang, Zeng, Xiangyi, Wang, Jie, Zeng, Pei, Li, Wenwen, Zhou, Xuelan, Zhang, Jin, Wang, Qisheng, Li, Jian
• Format: Journal Article
• Language: English
• Published: Netherlands 02.02.2024
• Subjects: mutation; crystal; protein; suppressant; virus
• ISSN: 1089-8638

The main protease (M ) of coronaviruses participates in viral replication, serving as a hot target for drug design. GC376 is able to effectively inhibit the activity of M , which is due to nucleophilic addition of GC376 by binding covalently with Cys145 in M active site. Here, we used fluorescence resonance energy transfer (FRET) to analyze the IC values of GC376 against M s from six different coronaviruses (SARS-CoV-2, HCoV-229E, HCoV-HUK1, MERS-CoV, SARS-CoV, HCoV-NL63) and five M mutants (G15S, M49I, K90R, P132H, S46F) from SARS-CoV-2 variants. The results showed that GC376 displays effective inhibition to various coronaviral M s and SARS-CoV-2 M mutants. In addition, the crystal structures of SARS-CoV-2 M (wide type)-GC376, SARS-CoV M -GC376, MERS-CoV M -GC376, and SARS-CoV-2 M mutants (G15S, M49I, S46F, K90R, and P132H)-GC376 complexes were solved. We found that GC376 is able to fit into the active site of M s from different coronaviruses and different SARS-CoV-2 variants properly. Detailed structural analysis revealed key molecular determinants necessary for inhibition and illustrated the binding patterns of GC376 to these different M s. In conclusion, we not only proved the inhibitory activity of GC376 against different M s including SARS-CoV-2 M mutants, but also revealed the molecular mechanism of inhibition by GC376, which will provide scientific guidance for the development of broad-spectrum drugs against SARS-CoV-2 as well as other coronaviruses.