Flavonoid-mediated inhibition of SARS coronavirus 3C-like protease expressed in Pichia pastoris

Biotechnol Lett. 2012 May;34(5):831-8. doi: 10.1007/s10529-011-0845-8. Epub 2012 Feb 15.

Abstract

The 3C-like protease (3CL(pro)) of severe acute respiratory syndrome associated coronavirus (SARS-CoV) is vital for SARS-CoV replication and is a promising drug target. Recombinant 3CL(pro) was expressed in Pichia pastoris GS115 as a 42 kDa protein that displayed a K ( m ) of 15 ± 2 μM with Dabcyl-KTSAVLQSGFRKME-Edans as substrate. Purified 3CL(pro) was used for inhibition and kinetic assays with seven flavonoid compounds. The IC(50) of six flavonoid compounds were 47-381 μM. Quercetin, epigallocatechin gallate and gallocatechin gallate (GCG) displayed good inhibition toward 3CL(pro) with IC(50) values of 73, 73 and 47 μM, respectively. GCG showed a competitive inhibition pattern with K ( i ) value of 25 ± 1.7 μM. In molecular docking experiments, GCG displayed a binding energy of -14 kcal mol(-1) to the active site of 3CL(pro) and the galloyl moiety at 3-OH position was required for 3CL(pro) inhibition activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catechin / analogs & derivatives
  • Catechin / metabolism
  • Coronavirus 3C Proteases
  • Cysteine Endopeptidases / biosynthesis
  • Cysteine Endopeptidases / chemistry
  • Cysteine Endopeptidases / genetics
  • Flavonoids / metabolism*
  • Gene Expression
  • Hydrolysis
  • Inhibitory Concentration 50
  • Kinetics
  • Molecular Weight
  • Pichia / genetics
  • Protease Inhibitors / metabolism*
  • Recombinant Proteins / antagonists & inhibitors
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • SARS Virus / enzymology*
  • SARS Virus / genetics
  • Viral Proteins / antagonists & inhibitors*
  • Viral Proteins / biosynthesis
  • Viral Proteins / chemistry
  • Viral Proteins / genetics

Substances

  • Flavonoids
  • Protease Inhibitors
  • Recombinant Proteins
  • Viral Proteins
  • gallocatechin gallate
  • Catechin
  • epigallocatechin gallate
  • Cysteine Endopeptidases
  • Coronavirus 3C Proteases