Design, synthesis and characterization of novel inhibitors against mycobacterial β-ketoacyl CoA reductase FabG4

Org Biomol Chem. 2014 Jan 7;12(1):73-85. doi: 10.1039/c3ob41676c. Epub 2013 Oct 16.

Abstract

We report the design and synthesis of triazole-polyphenol hybrid compounds 1 and 2 as inhibitors of the FabG4 (Rv0242c) enzyme of Mycobacterium tuberculosis for the first time. A major advance in this field occurred only a couple of years ago with the X-ray crystal structure of FabG4, which has helped us to design these inhibitors by the computational fragment-based drug design (FBDD) approach. Compound 1 has shown competitive inhibition with an inhibition constant (Ki) value of 3.97 ± 0.02 μM. On the other hand, compound 2 has been found to be a mixed type inhibitor with a Ki value of 0.88 ± 0.01 μM. Thermodynamic analysis using isothermal titration calorimetry (ITC) reveals that both inhibitors bind at the NADH co-factor binding domain. Their MIC values, as determined by resazurin assay against M. smegmatis, indicated their good anti-mycobacterial properties. A preliminary structure-activity relationship (SAR) study supports the design of these inhibitors. These compounds may be possible candidates as lead compounds for alternate anti-tubercular drugs. All of the reductase enzymes of the Mycobacterium family have a similar ketoacyl reductase (KAR) domain. Hence, this work may be extrapolated to find structure-based inhibitors of other reductase enzymes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3-Oxoacyl-(Acyl-Carrier-Protein) Reductase / antagonists & inhibitors*
  • 3-Oxoacyl-(Acyl-Carrier-Protein) Reductase / metabolism
  • Antitubercular Agents / chemical synthesis
  • Antitubercular Agents / chemistry
  • Antitubercular Agents / pharmacology*
  • Dose-Response Relationship, Drug
  • Drug Design*
  • Enzyme Inhibitors / chemical synthesis
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology*
  • Microbial Sensitivity Tests
  • Models, Molecular
  • Molecular Structure
  • Mycobacterium tuberculosis / drug effects*
  • Mycobacterium tuberculosis / enzymology
  • Polyphenols / chemistry*
  • Structure-Activity Relationship
  • Triazoles / chemistry*

Substances

  • Antitubercular Agents
  • Enzyme Inhibitors
  • Polyphenols
  • Triazoles
  • 3-Oxoacyl-(Acyl-Carrier-Protein) Reductase