Study On Biological Functions Of Severe Acute Respiratory Syndrome Coronavirus Papain-like Protease

In this study, we constructed cut-off mutagenesis and site-direct mutagenesis through cloning technology to investigate the molecular mechanism of SARS-CoV papain-like protease (PLpro) on the deubiquitinating, deISGylating and deSUMOylating process. Our result shew that the proteolytic tried-residuce active sites all could affect the PLpro`s deubiquiting activity. Among them, the C1651 is the majority functional residuce, while the H1812 and D1826 play supporting role; residuces C1651 and H1812 are necessary for the PLpro`s deISGylating activity. However, mutation of the D1826 to alanine no affect on PLpro`s deISGylating activity; solutio-PLpro no deSUMOylating activity, truncating the ubiquitin-like domain from PLpro did not effect its deubiquiting and deISGylating activity; solution-PLpro no deSUMOylating activity, the PLpro involve transmembrane domain (TM), however, have certain degree of deSUMOlating activity; truncating the NAB-G2M domain from PLpro-TM did not effect its deSUMOlating activity , indicating that the nuclear-around-mamberane locating function of transmembrane domain playes an important role in the deSUMOlating activity of PLpro-TM , in which NAB-G2M domain is not involved.