Functional Analyses of the Three Simian Hemorrhagic Fever Virus Nonstructural Protein 1 Papain-Like Proteases

• DOI: 10.1128/jvi.01020-14
• Publication Date: 2014-06-05T01:56:57Z
• Authors: Heather A. Vatter; Han Di; Eric F. Donaldson; Gertrud U. Radu; Taronna R. Maines; Margo A. Brinton
• Keywords: Polyproteins; Cleavage (geology); Arterivirus; NS3

ABSTRACT The N-terminal region of simian hemorrhagic fever virus (SHFV) nonstructural polyprotein 1a is predicted to encode three papain-like proteases (PLP1α, PLP1β, and PLP1γ). Catalytic residues cleavage sites for each the SHFV PLP1s were by alignment PLP1 sequences with other as well those arteriviruses, catalytic shown be proximal homology modeling nsp1s on porcine respiratory reproductive syndrome (PRRSV) nsp1 crystal structures. functionality Cys was tested analysis autoproteolytic products generated in vitro transcription/translation reactions done wild-type or mutant constructs. Cleavage also analyzed mass spectroscopy selected immunoprecipitated products. data showed that an active protease. Cys63 identified PLP1α adjacent Ala instead canonical Tyr observed arterivirus PLP1s. PLP1γ able cleave at both downstream upstream junction sites. Although intermediate precursor polyproteins alternative cleaving within nsp1β produced reactions, Western blotting SHFV-infected, MA104 cell lysates protein-specific antibodies detected only mature proteins. IMPORTANCE unique among arteriviruses having protease 1 (PLP1) domains. Other one two This first functional study Analysis autoprocessing polypeptide fragment active, confirmed testing Several features discovered. being a Trp. cis single site, but can nsp1γ-nsp2 nsp1β-nsp1γ junctions. proteins infected cells.