title: Characterization of trans- and cis-cleavage activity of the SARS coronavirus 3CLpro protease: basis for the in vitro screening of anti-SARS drugs.
abstract: Severe acute respiratory syndrome (SARS) has been globally reported. A novel coronavirus (CoV), SARS-CoV, was identified as the etiological agent of the disease. SARS-CoV 3C-like protease (3CLpro) mediates the proteolytic processing of replicase polypeptides 1a and 1ab into functional proteins, playing an important role in viral replication. In this study, we demonstrated the expression of the SARS-CoV 3CLpro in Escherichia coli and Vero cells, and then characterized the in vitro trans-cleavage and the cell-based cis-cleavage by the 3CLpro. Mutational analysis of the 3CLpro demonstrated the importance of His41, Cys145, and Glu166 in the substrate-binding subsite S1 for keeping the proteolytic activity. In addition, alanine substitution of the cleavage substrates indicated that Gln-(P1) in the substrates mainly determined the cleavage efficiency. Therefore, this study not only established the quantifiable and reliable assay for the in vitro and cell-based measurement of the 3CLpro activity, but also characterized the molecular interaction of the SARS-CoV 3CLpro with the substrates. The results will be useful for the rational development of the anti-SARS drugs.
authors.affiliation: Department of Medical Laboratory Science and Biotechnology, China Medical University, No. 91, Hsueh-Shih Road, Taichung 404, Taiwan, ROC. cwlin@mail.cmu.edu.tw
authors.forename: Cheng-Wen
authors.initials: CW
authors.lastname: Lin
authors.forename: Chang-Hai
authors.initials: CH
authors.lastname: Tsai
authors.forename: Fuu-Jen
authors.initials: FJ
authors.lastname: Tsai
authors.forename: Pei-Jer
authors.initials: PJ
authors.lastname: Chen
authors.forename: Chien-Chen
authors.initials: CC
authors.lastname: Lai
authors.forename: Lei
authors.initials: L
authors.lastname: Wan
authors.forename: Hua-Hao
authors.initials: HH
authors.lastname: Chiu
authors.forename: Kuan-Hsun
authors.initials: KH
authors.lastname: Lin
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D001483:Base Sequence; D002522:Chlorocebus aethiops; D000086782:Coronavirus 3C Proteases; D003546:Cysteine Endopeptidases; D017931:DNA Primers; D010450:Endopeptidases / Q000378:metabolism*; D006868:Hydrolysis; D045473:Severe acute respiratory syndrome-related coronavirus / Q000187:drug effects* / Q000201:enzymology; D014709:Vero Cells; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D000998:Antiviral Agents; D017931:DNA Primers; D014764:Viral Proteins; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; D000086782:Coronavirus 3C Proteases