id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-268930-y1cm58r6	van Aken, Danny	Expression, purification, and in vitro activity of an arterivirus main proteinase	2006-03-09		.txt	text/plain	7515	344	56	To allow the biochemical and structural characterization of the chymotrypsin-like "main proteinase" (non-structural protein 4; nsp4) of the arterivirus prototype Equine Arteritis Virus (EAV), we developed protocols for the large-scale production of recombinant nsp4 in Escherichia coli. In a synthetic peptide-based activity assay, the potential of the recombinant proteinase to cleave peptides mimicking the P9–P7′ residues of six nsp4 cleavage sites was investigated. To test whether active recombinant proteinases had been isolated, the proteolytic activity of purified MBP-nsp4 and nsp4His was tested in cleavage assays using in vitro synthesized substrates as described in Section 2. Although it was reported that the addition of six His residues strongly inhibited the enzymatic activity of the human coronavirus 229E 3CL pro proteinase (Ziebuhr et al., 1997) , in both our assays the catalytic activity of nsp4His was very comparable to that of partially purified uncleaved or cleaved MBP-nsp4.	./cache/cord-268930-y1cm58r6.txt	./txt/cord-268930-y1cm58r6.txt