Tafenoquine and its derivatives as inhibitors for the severe acute respiratory syndrome coronavirus 2.
Chen, Y., Yang, W.H., Chen, H.F., Huang, L.M., Gao, J.Y., Lin, C.W., Wang, Y.C., Yang, C.S., Liu, Y.L., Hou, M.H., Tsai, C.L., Chou, Y.Z., Huang, B.Y., Hung, C.F., Hung, Y.L., Wang, W.J., Su, W.C., Kumar, V., Wu, Y.C., Chao, S.W., Chang, C.S., Chen, J.S., Chiang, Y.P., Cho, D.Y., Jeng, L.B., Tsai, C.H., Hung, M.C.(2022) J Biol Chem 298: 101658-101658
- PubMed: 35101449 
- DOI: https://doi.org/10.1016/j.jbc.2022.101658
- Primary Citation of Related Structures:  
7DDC - PubMed Abstract: 
The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has severely affected human lives around the world as well as the global economy. Therefore, effective treatments against COVID-19 are urgently needed. Here, we screened a library containing Food and Drug Administration (FDA)-approved compounds to identify drugs that could target the SARS-CoV-2 main protease (M pro ), which is indispensable for viral protein maturation and regard as an important therapeutic target. We identified antimalarial drug tafenoquine (TFQ), which is approved for radical cure of Plasmodium vivax and malaria prophylaxis, as a top candidate to inhibit M pro protease activity. The crystal structure of SARS-CoV-2 M pro in complex with TFQ revealed that TFQ noncovalently bound to and reshaped the substrate-binding pocket of M pro by altering the loop region (residues 139-144) near the catalytic Cys145, which could block the catalysis of its peptide substrates. We also found that TFQ inhibited human transmembrane protease serine 2 (TMPRSS2). Furthermore, one TFQ derivative, compound 7, showed a better therapeutic index than TFQ on TMPRSS2 and may therefore inhibit the infectibility of SARS-CoV-2, including that of several mutant variants. These results suggest new potential strategies to block infection of SARS-CoV-2 and rising variants.
Organizational Affiliation: 
Institute of New Drug Development, China Medical University, Taichung, Taiwan; Drug Development Center, China Medical University, Taichung, Taiwan; Research Center for Cancer Biology, China Medical University, Taichung, Taiwan. Electronic address: bluecrystalprotein@gmail.com.