Direct Staudinger-Phosphonite Reaction Provides Methylphosphonamidates as Inhibitors of CE4 De-N-acetylases

Chembiochem. 2015 Jun 15;16(9):1350-6. doi: 10.1002/cbic.201500091. Epub 2015 May 26.

Abstract

De-N-acetylases of β-(1→6)-D-N-acetylglucosamine polymers (PNAG) and β-(1→4)-D-N-acetylglucosamine residues in peptidoglycan are attractive targets for antimicrobial agents. PNAG de-N-acetylases are necessary for biofilm formation in numerous pathogenic bacteria. Peptidoglycan de-N-acetylation facilitates bacterial evasion of innate immune defenses. To target these enzymes, transition-state analogue inhibitors containing a methylphosphonamidate have been synthesized through a direct Staudinger-phosphonite reaction. The inhibitors were tested on purified PgaB, a PNAG de-N-acetylase from Escherichia coli, and PgdA, a peptidoglycan de-N-acetylase from Streptococcus pneumonia. Herein, we describe the most potent inhibitor of peptidoglycan de-N-acetylases reported to date (Ki =80 μM). The minimal inhibition of PgaB observed provides insight into key structural and functional differences in these enzymes that will need to be considered during the development of future inhibitors.

Keywords: Staudinger reaction; de-N-acetylase; inhibitors; methylphosphonamidate; transition states.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylglucosamine / metabolism
  • Amidohydrolases / antagonists & inhibitors*
  • Amidohydrolases / metabolism
  • Bacterial Proteins / antagonists & inhibitors*
  • Bacterial Proteins / metabolism
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology*
  • Escherichia coli / drug effects
  • Escherichia coli / enzymology*
  • Escherichia coli Infections / drug therapy
  • Escherichia coli Infections / microbiology
  • Escherichia coli Proteins / antagonists & inhibitors*
  • Escherichia coli Proteins / metabolism
  • Humans
  • Methylation
  • Organophosphorus Compounds / chemistry
  • Organophosphorus Compounds / pharmacology*
  • Peptidoglycan / metabolism
  • Pneumococcal Infections / drug therapy
  • Pneumococcal Infections / microbiology
  • Streptococcus pneumoniae / drug effects
  • Streptococcus pneumoniae / enzymology*

Substances

  • Bacterial Proteins
  • Enzyme Inhibitors
  • Escherichia coli Proteins
  • Organophosphorus Compounds
  • Peptidoglycan
  • Amidohydrolases
  • poly-beta-1,6-N-acetyl-D-glucosamine de-N-acetylase, E coli
  • pgdA protein, Streptococcus pneumoniae
  • Acetylglucosamine