NMR identification of anti-influenza lead compound targeting at PAC subunit of H5N1 polymerase

PAC subunit from avian influenza (H5N1) viral RNA polymerase was used in this work as a target in the screening for anti-influenza agents from licorice-derived compounds. As a result, 18β-glycyrrhetinic acid was suggested to be PAC ligand by flexible docking, and was then confirmed by relaxation-edited NMR. The result of ApG primer extension assay indicated that this PAC ligand can inhibit the polymerase activity, and thus may potentially be valuable as anti-influenza lead compound. This work validated the possibility of screening polymerase inhibitors by using PAC as a target, and provided a starting point for the further discovery of new anti-influenza drugs.