Fig. 7.

The average potential curve of each composite system in umbrella sampling. The curve reflects the binding ability of ACE2 and Spike-RBD in each complex. From the figure, it can be found that the binding ability of ACE2 and SARS-CoV-2 in the pangolin system is the highest, while the difference between the human host and the pangolin is very small, followed by Cat and Chinese chrysanthemum bat ACE2. As a reference host, mice ACE2 has the low binding force with SARS-CoV/SARS-CoV-2, respectively.