has part has part has_part is AA variant of has mutated from has amino acid position isoleucine threonine SARS-CoV-2 Eta variant S3159T in SARS-CoV-2 pp1a protein 3159 An AA mutation or AA variant that has mutated an amino acid at position 3159 into threonine in pp1a. Anthony Huffman https://cov-lineages.org/ pp1a-S3159T AA variant in SARS-CoV-2 nsp4 protein