Synthesis of Pyrazole-Based Inhibitors of the Bacterial Enzyme N-Succinyl-l,l-2,6-Diaminopimelic Acid Desuccinylase (DapE) as Potential Antibiotics

Int J Mol Sci. 2024 Dec 24;26(1):22. doi: 10.3390/ijms26010022.

Abstract

Based on the inhibitory potencies from earlier reported tetrazole thioether analogs, we now describe the synthesis and inhibition of pyrazole-based inhibitors of N-succinyl-l,l-2,6-diaminopimelic acid desuccinylase (DapE) from Haemophilus influenzae (HiDapE). The most potent pyrazole analog 7d bears an aminopyridine amide with an IC50 of 17.9 ± 8.0 μM, and the single enantiomer of ɑ-methyl analog 7q has an IC50 of 18.8 µM, with potency residing in the (R)-enantiomer. Thermal shift revealed strong stabilization upon binding inhibitor (R)-7q with Tm = 50.2 °C and a Ki of 17.3 ± 2.8 μM. Enzyme kinetic experiments confirm competitive inhibition, and docking reveals key active site interactions.

Keywords: DapE; antibiotic; metalloenzyme; ninhydrin.

MeSH terms

  • Amidohydrolases* / antagonists & inhibitors
  • Amidohydrolases* / chemistry
  • Amidohydrolases* / metabolism
  • Anti-Bacterial Agents* / chemical synthesis
  • Anti-Bacterial Agents* / chemistry
  • Anti-Bacterial Agents* / pharmacology
  • Bacterial Proteins / antagonists & inhibitors
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / metabolism
  • Catalytic Domain
  • Enzyme Inhibitors* / chemical synthesis
  • Enzyme Inhibitors* / chemistry
  • Enzyme Inhibitors* / pharmacology
  • Haemophilus influenzae* / drug effects
  • Haemophilus influenzae* / enzymology
  • Kinetics
  • Molecular Docking Simulation*
  • Pyrazoles* / chemical synthesis
  • Pyrazoles* / chemistry
  • Pyrazoles* / pharmacology
  • Structure-Activity Relationship

Substances

  • Anti-Bacterial Agents
  • Pyrazoles
  • Amidohydrolases
  • N-succinyl-l,l-diaminopimelic acid desuccinylase
  • Enzyme Inhibitors
  • Bacterial Proteins
  • pyrazole