High Affinity Peptide Inhibitors of the Hepatitis C Virus Ns3-4A Protease Refractory to Common Resistant Mutants.
Kugler, J., Schmelz, S., Gentzsch, J., Haid, S., Pollmann, E., Van Den Heuvel, J., Franke, R., Pietschmann, T., Heinz, D.W., Collins, J.(2012) J Biol Chem 287: 39224
- PubMed: 22965230 
- DOI: https://doi.org/10.1074/jbc.M112.393843
- Primary Citation of Related Structures:  
4A1T, 4A1V, 4A1X - PubMed Abstract: 
Hepatitis C virus (HCV) NS3-4A protease is essential for viral replication. All current small molecular weight drugs against NS3-4A are substrate peptidomimetics that have a similar binding and resistance profile. We developed inhibitory peptides (IPs) capping the active site and binding via a novel "tyrosine" finger at an alternative NS3-4A site that is of particular interest for further HCV drug development. The peptides are not cleaved due to a combination of geometrical constraints and impairment of the oxyanion hole function. Selection and optimization through combinatorial phagemid display, protein crystallography, and further modifications resulted in a 32-amino acid peptide with a K(i) of 0.53 nm. Inhibition of viral replication in cell culture was demonstrated by fusion to a cell-penetrating peptide. Negligible susceptibility to known (A156V and R155K) resistance mutations of the NS3-4A protease was observed. This work shows for the first time that antiviral peptides can target an intracellular site and reveals a novel druggable site on the HCV protease.
Organizational Affiliation: 
Research Group Directed Evolution, Helmholtz Centre for Infection Research (HZI), 38124 Braunschweig, Germany.