Figure 4.  Inter-molecular hydrogen bond dynamics and structural superposition of the initial complex with the simulated RBD-ACE2-naltrexone complex during 100 ns MD. (A) Dynamics stability of RBD-ACE2-naltrexone complex with respect to inter-molecular hydrogen bonds along the 100 ns time scale. (B) Structural superimposed view of the starting complex used for MD (green) and the snapshot obtained from clustering analysis (cyan) of MD trajectory during the last 50 ns. (C) Inter-molecular contacts of the docked complex and MD simulated complex.