Broad Spectrum Inhibitors against Viral Methyltransferases

Case ID:

This innovation is a universal high throughput screening (HTS) assay to identify inhibitors targeting a binding site of viral methyltransferases (MTases) with a methyl donor. The inventors developed a fluorescence polarization (FP)-based HTS assay to target reference MTases, an essential enzyme to methylate the 5’-cap of viral RNA genome on SARS-CoV-2 and flavivirus. Pilot screening demonstrated that the HTS assay was very robust and identified two candidate inhibitors. Binding studies indicated that these molecules bound directly to the essential enzymes with similar low micromolar affinity. Moreover, the inventors further demonstrated that these molecules significantly inhibited the replication of SARS-CoV-2 and Zika virus in cell-based assays at concentrations not causing significant cytotoxicity. Overall, these molecules represent novel and promising candidates to further develop broad-spectrum inhibitors for management of viral infections.

The SARS-CoV-2 pandemic still persists even after vaccines have been introduced. Similarly, flaviviruses that cause diseases like Dengue Fever, West Nile Virus, Zika, and Japanese Encephalitis have caused outbreaks all over the world and there are only four working vaccines on the market for those conditions. These viruses often are zoonotic or use animals to infect humans. The single-stranded RNA allows for the viruses to quickly mutate and thus evade immune systems and human innovations, making it difficult for vaccines to remain 100% accurate. Viral methyltransferases methylate the 5’-cap of viral genome, so if there is a way to target methyltransferases then the viral genome would be left to unravel and be deemed useless for reproduction.


  • Screening assay to identify viral inhibitors
  • Treatment for virus breakouts
    • SARS-CoV-2
    • Flavivirus


  • Avoids quick mutation factors
  • Enzyme-based instead of antibody
Patent Information:
Contact For More Information:
Garrett Edmunds
Licensing Manager, UAHS-TLA
The University of Arizona
Lead Inventor(s):
Hongmin Li
Zhong Li