Probability of aligned pairs of residues found within 3.5 Å at the RBD1-ACE2 (shaded bars) and RBD2-ACE2 (black bars) interfaces using AMBER ff99SB FF performed by the Shaw group.

The first number corresponds to RBD based on alignment in Fig 1A. A stable pair is defined to have a probability larger than 60% during the simulation times. NOTE: S19 interactions are split into two parts that include the terminal group of residue-18 on ACE2.

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