| Coronavirus M pro cleavage site consensus sequence logo plots and comparisons. Logo plots from multiple alignments of the known M pro cleavage sites are shown for the 2003 SCoV (A) and 2019 SCoV2 (B). The height of a letter at each position reflects its probability in the alignment; each of the logos shown represents the consensus of 11 M pro cleavage sites from a single virus. Plots were generated using WebLogo (weblogo.berkeley.edu/logo.cgi), from the alignments in Figure S1. (C) Comparison of the GPX1 active site sequence containing selenocysteine (U) to the known SCoV2 M pro cleavage site at the nsp13/14 junction; this site is identical in the 2003 and 2019 coronaviruses. (D) Comparison of a predicted M pro cleavage site in human selenoprotein F to a known SCoV2 M pro cleavage site at the nsp12/13 junction.