Structure-activity relationships and enzyme inhibition of pantothenamide-type pantothenate kinase inhibitors

Bioorg Med Chem. 2006 Feb 15;14(4):1007-20. doi: 10.1016/j.bmc.2005.09.021. Epub 2005 Oct 5.

Abstract

A set of novel pantothenamide-type analogues of the known Staphylococcus aureus pantothenate kinase (SaPanK) inhibitors, N-pentyl, and N-heptylpantothenamide, was synthesized in three series. The first series of analogues (1-3) were designed as molecular probes of the PanK binding site to elucidate important structure-activity relationships (SAR). The second series of analogues (4-16) were designed using structural information obtained from the Escherichia coli PanK (EcPanK) structure by targeting the pantothenate binding site and the adjacent phenylalanine-lined lipophilic pocket. Insight into the antimicrobial effect of N-pentylpantothenamide (N5-Pan) through its conversion to the antimetabolite ethyldethia-CoA and further incorporation into an inactive acyl carrier protein analogue drove the development of the third series of analogues (17-25) to enhance this effect using substrate-like substitutions. Each of the analogues was screened for enzyme inhibition activity against a panel of pantothenate kinases consisting of EcPanK, Aspergillus nidulans (AnPanK), SaPanK, and the murine isoform (MmPanK1alpha). Series 1 demonstrated only modest inhibitory activity, but did reveal some important SAR findings including stereospecific binding. Series 2 demonstrated a much higher inhibition rate for the entire series and significant inhibition was seen with analogues containing alkyl substituents. Series 3 demonstrated the most preferential inhibition profile, with the highest inhibitory activity against the SaPanK and MmPanK1alpha. The MmPanK1alpha protein was inhibited by a broad spectrum of the compounds, whereas the E. coli enzyme showed greater selectivity. The overall activity data from these analogues suggest a complex and non-enzyme specific SAR for pantothenamide substrate/inhibitors of the different PanK enzymes.

MeSH terms

  • Binding Sites
  • Escherichia coli / drug effects
  • Escherichia coli / enzymology
  • Microbial Sensitivity Tests
  • Models, Molecular
  • Phosphotransferases (Alcohol Group Acceptor) / antagonists & inhibitors*
  • Phosphotransferases (Alcohol Group Acceptor) / chemistry
  • Phosphotransferases (Alcohol Group Acceptor) / metabolism
  • Protein Kinase Inhibitors / chemical synthesis*
  • Protein Kinase Inhibitors / chemistry
  • Protein Kinase Inhibitors / pharmacology*
  • Protein Structure, Tertiary
  • Staphylococcus aureus / drug effects
  • Staphylococcus aureus / enzymology
  • Structure-Activity Relationship

Substances

  • Protein Kinase Inhibitors
  • Phosphotransferases (Alcohol Group Acceptor)
  • pantothenate kinase