Amino acid sequences of the NS3/4A protease constructs engineered in this study.

<p>HCV (sample 1) and CHV NS3/4A protease constructs contain NS4 residues 21–34 fused in frame via a short linker to the amino terminus of the NS3 protease domain (residues 1–181). It was previously demonstrated that the kinetic parameters of a single-chain protein containing the NS4A cofactor and the HCV NS3 protease are identical to those of the bona fide NS3/4A (NS3 residues 1 to 631 and NS4A residues 1 to 54 protein complex generated in eukaryotic cells (5, 38). Asterisks represent the stop codons. Mutated residues generated by site-directed mutagenesis are marked in red.