Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.14.250258v1?rss=1 Authors: Chen, Y., Yang, W.-H., Huang, L.-M., 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., Chen, J.-S., Chiang, Y.-P., Cho, D.-Y., Jeng, L.-B., Tsai, C.-H., Hung, M.-C. Abstract: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing the current pandemic, coronavirus disease 2019 (COVID-19), has taken a huge toll on human lives and the global economy. Therefore, effective treatments against this disease are urgently needed. Here, we established a fluorescence resonance energy transfer (FRET)-based high-throughput screening platform to screen compound libraries to identify drugs targeting the SARS-CoV-2 main protease (Mpro), in particular those which are FDA-approved, to be used immediately to treat patients with COVID-19. Mpro has been shown to be one of the most important drug targets among SARS-related coronaviruses as impairment of Mpro blocks processing of viral polyproteins which halts viral replication in host cells. Our findings indicate that the anti-malarial drug tafenoquine (TFQ) induces significant conformational change in SARS-CoV-2 Mpro and diminishes its protease activity. Specifically, TFQ reduces the alpha-helical content of Mpro, which converts it into an inactive form. Moreover, TFQ greatly inhibits SARS-CoV-2 infection in cell culture system. Hence, the current study provides a mechanistic insight into the mode of action of TFQ against SARS-CoV-2 Mpro. Moreover, the low clinical toxicity of TFQ and its strong antiviral activity against SARS-CoV-2 should warrant further testing in clinical trials. Copy rights belong to original authors. Visit the link for more info