The coronavirus SARS-CoV-2 main protease, M
pro
, is conserved among
coronaviruses with no human homolog and has therefore attracted significant attention as
an enzyme drug target for COVID-19. The number of studies targeting M
pro
for
in silico screening has grown rapidly, and it would be of great interest to know in
advance how well docking methods can reproduce the correct ligand binding modes and rank
these correctly. Clearly, current attempts at designing drugs targeting M
pro
with the aid of computational docking would benefit from a priori knowledge of the
ability of docking programs to predict correct binding modes and score these correctly.
In the current work, we tested the ability of several leading docking programs, namely,
Glide, DOCK, AutoDock, AutoDock Vina, FRED, and EnzyDock, to correctly identify and
score the binding mode of M
pro
ligands in 193 crystal structures. None of the
codes were able to correctly identify the crystal structure binding mode (lowest energy
pose with root-mean-square deviation < 2 Å) in more than 26% of the cases for
noncovalently bound ligands (Glide: top performer), whereas for covalently bound ligands
the top score was 45% (EnzyDock). These results suggest that one should perform in
silico campaigns of M
pro
with care and that more comprehensive strategies
including ligand free energy perturbation might be necessary in conjunction with virtual
screening and docking.