We virtually screened our inhouse TüKIC library against M pro . This collection contains over 10,000 compounds targeting a variety of kinases. This library was previously prepared according to literature. The CatL protein structure was prepared from the PDB 2XU3 (Resolution: 0.90 Å) using the Protein Wizard Preparation tool with standard options. All water molecules from the original PDB were removed for docking but placed back for later MD simulations. For the virtual screening we used molecular docking, carried out with Glide SP (version 9.1). Grids were centered at the central point of the co-crystallized ligand. The top 500 hits, ranked by docking score, were visually inspected by observing the interaction with relevant residues and if reactive moieties would be near the catalytic cysteine.