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Herpesvirus protease inhibition by dimer disruption
Nobuhisa Shimba1, Anson M Nomura, Alan B Marnett
1Department of Pharmaceutical Chemistry, University of California-San Francisco, 600 16th St., Box 2280, San Francisco, CA 94143-2280, USA.
Journal of Virology
|May 28, 2004
Summary
A novel peptide disrupts Kaposi's sarcoma-associated herpesvirus protease (KSHV Pr) dimerization, inhibiting viral replication. This study highlights the viral protease dimer interface as a potential therapeutic target.
Area of Science:
- Virology
- Biochemistry
- Structural Biology
Background:
- Kaposi's sarcoma-associated herpesvirus (KSHV) protease (KSHV Pr) is essential for viral replication.
- Herpesvirus proteases function as dimers, but their active sites do not directly interact at the dimer interface.
Purpose of the Study:
- To design a peptide inhibitor that disrupts KSHV Pr dimerization.
- To investigate the KSHV Pr dimer interface as a potential drug target.
Main Methods:
- Protein grafting of a KSHV Pr alpha-helix onto avian pancreatic polypeptide to create a chimeric peptide.
- Protein modeling for peptide optimization.
- Circular dichroism and gel filtration chromatography to assess peptide conformation and dimerization disruption.
- Enzyme inhibition assays and site-directed mutagenesis to evaluate peptide efficacy and binding interactions.
Main Results:
- A rationally designed 30-amino-acid peptide adopts a helical structure and effectively disrupts KSHV Pr dimerization.
- The peptide inhibits KSHV Pr activity by 50% at a 200-fold molar excess, with a dissociation constant of 300 microM.
- Mutagenesis of an interfacial residue (M197L) increased the required inhibitory concentration, supporting the model of peptide binding at the dimer interface.
Conclusions:
- The dimer interface of KSHV Pr is a viable target for therapeutic intervention.
- Disrupting protease dimerization represents a novel strategy for inhibiting KSHV lytic cycle and viral activity.