Screening of drugs by FRET analysis identifies inhibitors of SARS-CoV 3CL protease

Biochem Biophys Res Commun. 2005 Jul 22;333(1):194-9. doi: 10.1016/j.bbrc.2005.05.095.


SARS-CoV 3CL protease is essential for viral protein processing and is regarded as a good drug target to prevent SARS-CoV replication. In the present study, we established a high-throughput FRET technique for screening for anti-SARS-CoV 3CL protease drugs. Of a thousand existing drugs examined, hexachlorophene was identified as the most potent in inhibiting SARS-CoV 3CL protease. Further characterization showed that it was effective at micromolar concentrations (K(i) = 4 microM). The binding mode was competitive, and the inhibitory effect was dependent on preincubation time. Two other drugs, triclosan and nelfinavir, were about 10 times less potent. The structure-based search and biological evaluation of various hexachlorophene analogues were described. These analogues gave optimal inhibitory activity against SARS-CoV 3CL protease with IC(50) values ranging from 7.6 to 84.5 microM. Optimization of hexachlorophene analogues was shown to provide several active 3CL protease inhibitors that function as potential anti-SARS agents.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Computer Simulation
  • Coronavirus 3C Proteases
  • Cysteine Endopeptidases
  • Drug Design*
  • Drug Evaluation, Preclinical / methods*
  • Endopeptidases / analysis
  • Enzyme Activation
  • Fluorescence Resonance Energy Transfer / methods*
  • Kinetics
  • Models, Molecular*
  • Protease Inhibitors / analysis
  • Protease Inhibitors / chemistry*
  • Protein Binding
  • Protein Interaction Mapping / methods*
  • Viral Proteins / analysis
  • Viral Proteins / antagonists & inhibitors*


  • Protease Inhibitors
  • Viral Proteins
  • Endopeptidases
  • Cysteine Endopeptidases
  • Coronavirus 3C Proteases