Crystal Structure of the N-Acetylmuramic Acid α-1-Phosphate (MurNAc-α1-P) Uridylyltransferase MurU, a Minimal Sugar Nucleotidyltransferase and Potential Drug Target Enzyme in Gram-negative Pathogens

J Biol Chem. 2015 Apr 24;290(17):10804-13. doi: 10.1074/jbc.M114.620989. Epub 2015 Mar 12.


The N-acetylmuramic acid α-1-phosphate (MurNAc-α1-P) uridylyltransferase MurU catalyzes the synthesis of uridine diphosphate (UDP)-MurNAc, a crucial precursor of the bacterial peptidoglycan cell wall. MurU is part of a recently identified cell wall recycling pathway in Gram-negative bacteria that bypasses the general de novo biosynthesis of UDP-MurNAc and contributes to high intrinsic resistance to the antibiotic fosfomycin, which targets UDP-MurNAc de novo biosynthesis. To provide insights into substrate binding and specificity, we solved crystal structures of MurU of Pseudomonas putida in native and ligand-bound states at high resolution. With the help of these structures, critical enzyme-substrate interactions were identified that enable tight binding of MurNAc-α1-P to the active site of MurU. The MurU structures define a "minimal domain" required for general nucleotidyltransferase activity. They furthermore provide a structural basis for the chemical design of inhibitors of MurU that could serve as novel drugs in combination therapy against multidrug-resistant Gram-negative pathogens.

Keywords: Bacteria; Cell Wall; Drug Resistance; Enzyme Structure; Fosfomycin; N-Acetylmuramic Acid α-1-Phosphate; Peptidoglycan Biosynthesis; Structural Biology; UDP-MurNAc.

MeSH terms

  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Catalytic Domain
  • Cloning, Molecular
  • Crystallography, X-Ray
  • Gram-Negative Bacteria / drug effects
  • Gram-Negative Bacteria / enzymology
  • Gram-Negative Bacteria / pathogenicity
  • Magnesium / chemistry
  • Models, Molecular
  • Nucleotidyltransferases / chemistry*
  • Nucleotidyltransferases / genetics
  • Nucleotidyltransferases / metabolism
  • Protein Conformation
  • Protein Structure, Tertiary
  • Pseudomonas putida / enzymology
  • Pseudomonas putida / genetics
  • Substrate Specificity
  • Uridine Diphosphate N-Acetylmuramic Acid / biosynthesis


  • Bacterial Proteins
  • Uridine Diphosphate N-Acetylmuramic Acid
  • Nucleotidyltransferases
  • Magnesium

Associated data

  • PDB/4Y7T
  • PDB/4Y7U
  • PDB/4Y7V