During replication of hepatitis C virus (HCV), the final steps of polyprotein processing are performed by a viral proteinase located in the N- terminal one-third of nonstructural protein 3. The structure of NS3 proteinase from HCV BK strain was determined by X-ray crystallography at 2.4 Å resolution. NS3P folds as a trypsin-like proteinase with two β barrels and a catalytic triad of His-57, Asp-81, Ser-139. The structure has a substrate-binding site consistent with the cleavage specificity of the enzyme. Novel features include a structural zinc-binding site and a long N- terminus that interacts with neighboring molecules by binding to a hydrophobic surface patch.
Love, R. A., Parge, H. E., Wickersham, J. A., Hostomsky, Z., Habuka, N., Moomaw, E. W., … Hostomska, Z. (1996). The crystal structure of hepatitis C virus NS3 proteinase reveals a trypsin-like fold and a structural zinc binding site. Cell, 87(2), 331–342. https://doi.org/10.1016/S0092-8674(00)81350-1