Figure 1. Coronavirus non-structural proteins (nsps).
(A) The N-terminal region of the polyprotein showing the two viral proteases (blue) with green arrows indicating the sites of cleavage mediated by the nsp3 papain-like protease (PLpro) and sites of cleavage of the nsp5 chymotrypsin-like protease (also known as 3CLpro or Main protease Mpro) in red. (B) The capping complex and replication transcription complex with the associated uridine specific endoribonuclease nsp15. Components studied in the drug discovery studies [1–7] indicated in blue.