His10-SARS-CoV-2 (PLpro)

 The severe acute respiratory syndrome coronavirus papain-like protease (SARS-CoV-2 PLpro) is involved in the processing of the viral polyprotein. Proteolytic processing of the coronavirus replicase poly-protein is essential for generating a functional virus replication complex. PLpro possesses both deubiquitinating or deISGylating activity and can process Lys- 48 and Lys-63 linked polyubiquitin chains (free chains or from cellular substrates). It works in concert together with nsp4 in the assembly of virally-induced cytoplasmic double-membrane vesicles necessary for viral replication. It strongly antagonizes the innate immune induction of type I interferon by blocking the phosphorylation, dimerization and therefore the nuclear translocation of host IRF3. In addition, it prevents also host NF-kappa-B signaling. SARS Cov-2 PLpro is very active hydrolyzing both ISG15- Rhodamine110 (SBB-PS0002) or di-ubiquitin/ tetra-ubiquitin substrates (Lys48 or Lys63 linked), but is very inefficient when processing mono-Ub conjugates e.g. Ub-AMC or synthetic peptide substrates e.g. RLRGG-AMC. This SARS Coronavirus recombinant PLpro is N-terminally His10-tagged and expressed in E.coli.