has part has part has_part is characteristic AA variant of has mutated from has amino acid position serine proline SARS-CoV-2 Omicron variant AA variant in SARS-CoV-2 S protein S1 RBD region S373P in SARS-CoV-2 S protein 373 https://cov-lineages.org/ An AA mutation or AA variant that has mutated an amino acid at position 373 into a proline in S protein. S-373P Anthony Huffman