three human coronavirus proteins. Protein sequence alignments are shown for nucleocapsid (N), membrane (M), and ORF1ab polyprotein (helicase) across all five known human betacoronaviruses (SARS-CoV-2, SARS-CoV, HKU1, OC43, and MERS-CoV) and two known human alphacoronaviruses (229E and NL63). Each row in the three depicted sequence alignments corresponds to the protein sequence from the indicated coronavirus, with the starting coord