Self-association studies of the bifunctional N-acetylglucosamine-1-phosphate uridyltransferase from Escherichia coli

Protein Sci. 2011 Apr;20(4):745-52. doi: 10.1002/pro.608. Epub 2011 Mar 11.


The N-acetylglucosamine-1-phosphate uridyltransferase (GlmU) is a key bifunctional enzyme in the biosynthesis of UDP-GlcNAc, a precursor in the synthesis of cell wall peptidoglycan. Crystal structures of the enzyme from different bacterial strains showed that the polypeptide forms a trimer through a unique parallel left-handed beta helix domain. Here, we show that the GlmU enzyme from Escherichia coli forms a hexamer in solution. Sedimentation equilibrium analytical ultracentrifugation demonstrated that the enzyme is in a trimer/hexamer equilibrium. Small-angle X-ray scattering studies were performed to determine the structure of the hexameric assembly and showed that two trimers assemble through their N-terminal domains. The interaction is mediated by a loop that undergoes a large conformational change in the uridyl transferase reaction, a feature that may affect the enzymatic activity of GlmU.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Crystallography, X-Ray
  • Escherichia coli / enzymology*
  • Escherichia coli Proteins / chemistry*
  • Models, Molecular
  • Nucleotidyltransferases / chemistry*
  • Protein Structure, Quaternary*
  • Protein Structure, Tertiary
  • Scattering, Small Angle


  • Escherichia coli Proteins
  • Nucleotidyltransferases
  • UDPacetylglucosamine pyrophosphorylase