All coronaviruses such as the SARS virus and the Middle East Respiratory Syndrome (MERS) virus encode in their genomes at least one papain-like protease (PLpro) enzyme which cleaves the viral replicase polyproteins at three sites releasing non-structural protein 1 (nsp1), nsp2 and nsp3. PLpro also possesses deubiquitinating and deISGylating activities. These have been suggested to suppress the host antiviral response by counteracting the post-translational modification of signalling molecules that activate the innate immune response. PLpro is made up of an N-terminal ubiquitin-like domain (found in many ubiquitin-specific proteases or USPs) and a C-terminal catalytic domain containing a right-handed fingers, palm, and thumb domain organisation.

This entry represents the thumb domain which consists of 6 alpha-helices.

PMID:25320088PMID:24854014