Important hydrogen bonds (H-bonds) and salt bridges between nCOV-2019 RBD or SARS-COV RBD and ACE2 for the last 400 ns of trajectory are shown in Table 1. nCOV-2019 RBD makes 10 H-bonds/1 salt bridge with ACE2, whereas SARS-COV makes only 5 H-bonds/1 salt bridge with ACE2 with more than 30% persistence.