1ns3
STRUCTURE OF HCV PROTEASE (BK STRAIN)
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OverviewOverview
The crystal structure of the NS3 protease of the hepatitis C virus (BK, strain) has been determined in the space group P6(3)22 to a resolution of, 2.2 A. This protease is bound with a 14-mer peptide representing the, central region of the NS4A protein. There are two molecules of the, NS3(1-180)-NS4A(21'-34') complex per asymmetric unit. Each displays a, familiar chymotrypsin-like fold that includes two beta-barrel domains and, four short alpha-helices. The catalytic triad (Ser-139, His-57, and, Asp-81) is located in the crevice between the beta-barrel domains. The, NS4A peptide forms an almost completely enclosed peptide surface, association with the protease. In contrast to the reported H strain, complex of NS3 protease-NS4A peptide in a trigonal crystal form (Kim JL et, al., 1996, Cell 87:343-355), the N-terminus of the NS3 protease is, well-ordered in both molecules in the asymmetric unit of our hexagonal, crystal form. The folding of the N-terminal region of the NS3 protease is, due to the formation of a three-helix bundle as a result of crystal, packing. When compared with the unbound structure (Love RA et al., 1996, Cell 87:331-342), the binding of the NS4A peptide leads to the ordering of, the N-terminal 28 residues of the NS3 protease into a beta-strand and an, alpha-helix and also causes local rearrangements important for a, catalytically favorable conformation at the active site. Our analysis, provides experimental support for the proposal that binding of an, NS4A-mimicking peptide, which increases catalytic rates, is necessary but, not sufficient for formation of a well-ordered, compact and, hence, highly, active protease molecule.
About this StructureAbout this Structure
1NS3 is a Protein complex structure of sequences from Hepatitis c virus with ZN as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Complex of NS3 protease and NS4A peptide of BK strain hepatitis C virus: a 2.2 A resolution structure in a hexagonal crystal form., Yan Y, Li Y, Munshi S, Sardana V, Cole JL, Sardana M, Steinkuehler C, Tomei L, De Francesco R, Kuo LC, Chen Z, Protein Sci. 1998 Apr;7(4):837-47. PMID:9568891
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