Here we use MD to investigate the structural changes of three X77/Mpro complex structures (PDBids 8P57, 7PHZ, 6W63) solved in different saturation conditions and space groups, on passing from the solid state to the aqueous solution. Specifically, we perform 500ns-long AMBER-based molecular dynamics simulations in explicit solvent of these systems. The Mpro structure and ligand pose remains stable during 500 ns of unbiased simulations for all the three simulated systems (see Fig. ). The number of contacts between the two subunits is conserved for the systems with both cavities occupied (7PHZ, 6W63, Fig. ), independently of the space group, while, for the single-cavity occupied system, this number increases, tightening up the subunit-to-subunit interaction (Fig. ).