Drug-Repurposing Screening Identifies a Gallic Acid Binding Site on SARS-CoV-2 Non-structural Protein 7

SARS-CoV-2 is the agent responsible for acute respiratory disease COVID-19 and the global pandemic initiated in early 2020. While the record-breaking development of vaccines has assisted the control of COVID-19, there is still a pressing global demand for antiviral drugs to halt the destructive impact of this disease. Repurposing clinically approved drugs provides an opportunity to expediate SARS-CoV-2 treatments into the clinic. In an effort to facilitate drug repurposing, an FDA-approved drug library containing 2400 compounds was screened against the SARSCoV-2 non-structural protein 7 (nsp7) using a native mass spectrometry-based assay. Nsp7 is one of the components of the SARS-CoV-2 replication/transcription complex essential for optimal viral replication, perhaps serving to off-load RNA from nsp8. From this library, gallic acid was identified as a compound that bound tightly to nsp7, with an estimated Kd of 15 mu M. NMR chemical shift perturbation experiments were used to map the ligand-binding surface of gallic acid on nsp7, indicating that the compound bound to a surface pocket centered on one of the protein's four alpha-helices (alpha 2). The identification of the gallic acid-binding site on nsp7 may allow development of a SARS-CoV-2 therapeutic via artificial intelligence-based virtual docking and other strategies.

Automated summary

SARS-CoV-2 is the pathogen responsible for COVID-19 and the global pandemic. Repurposing clinically approved drugs, gallic acid was identified as a compound that tightly binds to nsp7, a component essential for viral replication. The identification of the gallic acid-binding site may enable the development of a SARS-CoV-2 therapeutic through virtual docking and other strategies.