Fig. 2. (a) The S protein of SARS-CoV-2 (Omicron S-open-2, PDB: 7WVO): chains A–C with receptor-binding domain (RBD). (b) Cryo-EM structure of SARS-CoV-2 spike protein in complex with angiotensin-converting enzyme 2 (ACE2) shown in gold (PDB: 8HFZ). A close-up representation of the RBD protein and ACE2 interface. The sticks represent the key residues that interact with the ACE2. Numerous atomic connections are made between SARS-CoV-2 RBD (violet) and ACE2 (gold).