Journal article

Publication year: 2013

Pages: 11872-11883

Journal: Journal of Virology

Volume number: 87

Issue number: 21

ISSN: 0022-538X

eISSN: 1098-5514

DOI Link: https://doi.org/10.1128/JVI.00754-13

Publisher: American Society for Microbiology

Abstract: 
Classical swine fever virus (CSFV) is a positive-strandedRNAvirus belonging to the genus Pestivirus within the Flaviviridae family. Pivotal for processing of a large portion of the viral polyprotein is a serine protease activity within nonstructural protein 3 (NS3) that also harbors helicase and NTPase activities essential forRNAreplication. In CSFV-infected cells, NS3 appears as two forms, a fully processed NS3 of 80 kDa and the precursor molecule NS2-3 of 120 kDa. Here we report the identification and mapping of additional autocatalytic intramolecular cleavages. One cleavable peptide bond occurs between Leu(1781) and Met(1782), giving rise to a helicase subunit of 55 kDa and, depending on the substrate, a NS2-3 fragment of 78 kDa (NS2-3p) or a NS3 protease subunit of 26 kDa (NS3p). In transcleavage assays using NS4-5 as a substrate, NS3p acts as a fully functional protease that is able to process the polyprotein. NS3p comprises the minimal essential protease, as deletion of Leu1781 results in inactivation. A second intramolecular cleavage was mapped to the Leu(1748)/Lys(1749) peptide bond that yields a proteolytically inactive NS3 fragment. Deletion of either of the cleavage site residues resulted in a loss ofRNAinfectivity, indicating the functional importance of amino acid identity at the respective positions. Our data suggest that internal cleavage within the NS3 moiety is a common process that further extends the functional repertoires of the multifunctional NS2-3 or NS3 and represents another level of the complex polyprotein processing of Flaviviridae.

Harvard Citation style: Lamp, B., Riedel, C., Wentz, E., Tortorici, M. and Rümenapf, T. (2013) Autocatalytic Cleavage within Classical Swine Fever Virus NS3 Leads to a Functional Separation of Protease and Helicase, Journal of Virology, 87(21), pp. 11872-11883. https://doi.org/10.1128/JVI.00754-13

APA Citation style: Lamp, B., Riedel, C., Wentz, E., Tortorici, M., & Rümenapf, T. (2013). Autocatalytic Cleavage within Classical Swine Fever Virus NS3 Leads to a Functional Separation of Protease and Helicase. Journal of Virology. 87(21), 11872-11883. https://doi.org/10.1128/JVI.00754-13