A Fluorescence Polarization Assay for Macrodomains Facilitates the Identification of Potent Inhibitors of the SARS-CoV-2 Macrodomain.
Anmangandla, A., Jana, S., Peng, K., Wallace, S.D., Bagde, S.R., Drown, B.S., Xu, J., Hergenrother, P.J., Fromme, J.C., Lin, H.(2023) ACS Chem Biol 18: 1200-1207
- PubMed: 37126856 
- DOI: https://doi.org/10.1021/acschembio.3c00092
- Primary Citation of Related Structures:  
8GIA - PubMed Abstract: 
Viral macrodomains, which can bind to and/or hydrolyze adenine diphosphate ribose (ADP-ribose or ADPr) from proteins, have been suggested to counteract host immune response and be viable targets for the development of antiviral drugs. Therefore, developing high-throughput screening (HTS) techniques for macrodomain inhibitors is of great interest. Herein, using a novel tracer TAMRA-ADPr , an ADP-ribose compound conjugated with tetramethylrhodamine, we developed a robust fluorescence polarization assay for various viral and human macrodomains including SARS-CoV-2 Macro1, VEEV Macro, CHIKV Macro, human MacroD1, MacroD2, and PARP9 Macro2. Using this assay, we validated Z8539 (IC 50 6.4 μM) and GS441524 (IC 50 15.2 μM), two literature-reported small-molecule inhibitors of SARS-CoV-2 Macro1. Our data suggest that GS441524 is highly selective for SARS-CoV-2 Macro1 over other human and viral macrodomains. Furthermore, using this assay, we identified pNP-ADPr (ADP-ribosylated p -nitrophenol, IC 50 370 nM) and TFMU-ADPr (ADP-ribosylated trifluoromethyl umbelliferone, IC 50 590 nM) as the most potent SARS-CoV-2 Macro1 binders reported to date. An X-ray crystal structure of SARS-CoV-2 Macro1 in complex with TFMU-ADPr revealed how the TFMU moiety contributes to the binding affinity. Our data demonstrate that this fluorescence polarization assay is a useful addition to the HTS methods for the identification of macrodomain inhibitors.
Organizational Affiliation: 
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States.