Abstract
3CLpro
is a vital protein for the SARS-CoV-2 replications and its inhibition using
small molecules is a bona fide approach used to develop new drugs
against the virus. In this study, a comprehensive crystallography-guided
fragment-based drug discovery approach was employed to design new inhibitors
for SARS-CoV-2 3CLpro. Protein Data Bank was explored to find small molecules
cocrystallized with SARS-CoV-2 3CLpro. The fragments sitting in the binding
pocket (87) were interactively coupled using various linkers with the intention
to get molecules having the same orientation as those of the constituting
fragments. In total, 1251 couples were prepared and converted to maximum
possible stereoisomers using LigPrep for screening using Glide (standard
precision and extra precision), AutoDock Vina, and Prime MMGBSA. Top 22 hits having
conformations similar to their cocrystallized fragments were selected for MD
simulation on Desmond. MD simulation suggested that 15 hits had conformations
very close to their constituting fragments. Results indicated that these hits
were computationally reliable and could be considered for further development. This
suggests that the study could provide a benchmark starting point for the further
design of SARS-CoV-2 3CLpro inhibitors with improved binding (data provided).