Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (10): 2418-2422.doi: 10.3866/PKU.WHXB201209143

• BIOPHYSICAL CHEMISTRY • Previous Articles     Next Articles

Isatin Dual Functional Inhibitors: Modulating the Aggregation State and Enzyme Activity of SARS-3CL Proteinase

ZHOU Lu1,3, JIN Feng1,LIU Ying1,2, SHANG Er-Chang1, WEI Ping1, LI Chun-Mei1, LAI Lu-Hua1,2   

  1. 1 Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Structural Chemistry of Unstable and Stable Species, Institute of Physical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China;
    2 Center for Quantitative Biology, Peking University, Beijing 100871, P. R. China;
    3 School of Pharmacy, Fudan University, Shanghai 201203, P. R. China
  • Received:2012-07-25 Revised:2012-09-10 Published:2012-09-26
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (90913021, 20473001, 11021463) and National Key Basic Research Program of China (973) (2009CB9185003).


The 1-(2-naphthlmethyl) isatin-5-formamide compounds can inhibit SARS-3CL proteinase by binding to its substrate pocket, while the N-terminal octapeptide of SARS-3CL proteinase was found to act as a dimerization inhibitor. In this work, the dual functional inhibitors which can occupy both substrate pocket of SARS-3CL proteinase and its dimer interface were designed. Six title compounds were gotten by linking 1-(2-naphthlmethyl) isatin-5-formic acid and N-terminal octapeptides using a polyglycine linker through solid-phase peptide synthesis method. The in vitro inhibition activity against SARS-3CL proteinase was measured by continuous colorimetric assay using colorimetric substrate. Compound 3 showed the highest inhibition activity with an IC50 (half maximal inhibitory concentration of a substance) of 3.8 μmol·L-1. The change of inhibition activity with the linker length was studied. Inhibitors with the even spacers were showed better activity than the odd ones, which could be explained by the angle restriction of peptide bonds. The modulating of the aggregation state and enzyme activity towards SARS-3CL proteinase were studied using sedimentation velocity experiments. Compound 3 was found to not only inhibit the enzyme activity of SARS-3CL proteinase, but also shift the monomer-dimer equilibrium of the enzyme. The integrated control result is inhibiting SARS-3CL proteinase dimer formation. This work provides an example of using synthesized compounds to study enzyme activity regulation mechanism.

Key words: Isatin derivative, Modulation, SARS-3CL proteinase, Dimerization, Dual functional inhibitor


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