title: A loop-mimetic inhibitor of the HCV-NS3 protease derived from a minibody.
abstract: We have been interested for some time in establishing a strategy for deriving lead compounds from macromolecule ligands such as minibody variants. A minibody is a minimized antibody variable domain whose two loops are amenable to combinatorial mutagenesis. This approach can be especially useful when dealing with 'difficult' targets. One such target is the NS3 protease of hepatitis C virus (HCV), a human pathogen that is believed to infect about 100 million individuals worldwide and for which an effective therapy is not yet available. Based on known inhibitor specificity (residues P6-P1) of NS3 protease, we screened a number of minibodies from our collection and we were able to identify a competitive inhibitor of this enzyme. We thus validated an aspect of recognition by HCV NS3 protease, namely that an acid anchor is necessary for inhibitor activity. In addition, the characterization of the minibody inhibitor led to the synthesis of a constrained hexapeptide mimicking the bioactive loop of the parent macromolecule. The cyclic peptide is a lead compound prone to rapid optimization through solid phase combinatorial chemistry. We therefore confirmed that the potential of turning a protein ligand into a low molecular weight active compound for lead discovery is achievable and can complement more traditional drug discovery approaches.
authors.affiliation: Istituto di Ricerche di Biologia Molecolare (IRBM) P. Angeletti,Via Pontina Km 30,600-00040, Pomezia (Roma), Italy.
authors.forename: F
authors.initials: F
authors.lastname: Martin
authors.forename: C
authors.initials: C
authors.lastname: Steinkühler
authors.forename: M
authors.initials: M
authors.lastname: Brunetti
authors.forename: A
authors.initials: A
authors.lastname: Pessi
authors.forename: R
authors.initials: R
authors.lastname: Cortese
authors.forename: R
authors.initials: R
authors.lastname: De Francesco
authors.forename: M
authors.initials: M
authors.lastname: Sollazzo
mesh_terms: D001665:Binding Sites; D001667:Binding, Competitive; D020650:Combinatorial Chemistry Techniques; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000276:immunology; D016174:Hepacivirus / Q000201:enzymology* / Q000276:immunology; D007135:Immunoglobulin Variable Region / Q000737:chemistry* / Q000494:pharmacology; D007700:Kinetics; D008958:Models, Molecular; D010456:Peptides, Cyclic / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology; D011994:Recombinant Proteins / Q000737:chemistry; D017361:Viral Nonstructural Proteins / Q000037:antagonists & inhibitors* / Q000276:immunology; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D004791:Enzyme Inhibitors; D007135:Immunoglobulin Variable Region; D010456:Peptides, Cyclic; D011994:Recombinant Proteins; D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases