Discovery of a Glutamine Kinase Required for the Biosynthesis of the O-Methyl Phosphoramidate Modifications Found in the Capsular Polysaccharides of Campylobacter jejuni

J Am Chem Soc. 2017 Jul 19;139(28):9463-9466. doi: 10.1021/jacs.7b04824. Epub 2017 Jul 3.


Bacterial capsular polysaccharides (CPS) are complex carbohydrate structures that play a role in the overall fitness of the organism. Campylobacter jejuni, known for being a major cause of bacterial gastroenteritis worldwide, produces a CPS with a unique O-methyl phosphoramidate (MeOPN) modification on specific sugar residues. The formation of P-N bonds in nature is relatively rare, and the pathway for the assembly of the phosphoramidate moiety in the CPS of C. jejuni is unknown. In this investigation we discovered that the initial transformation in the biosynthetic pathway for the MeOPN modification of the CPS involves the direct phosphorylation of the amide nitrogen of l-glutamine with ATP by the catalytic activity of Cj1418. The other two products are AMP and inorganic phosphate. The l-glutamine-phosphate product was characterized using 31P NMR spectroscopy and mass spectrometry. We suggest that this newly discovered enzyme be named l-glutamine kinase.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amides / chemistry
  • Amides / metabolism*
  • Bacterial Capsules / chemistry
  • Bacterial Capsules / metabolism*
  • Campylobacter jejuni / chemistry
  • Campylobacter jejuni / enzymology*
  • Campylobacter jejuni / metabolism
  • Glutamine / chemistry
  • Glutamine / metabolism*
  • Humans
  • Molecular Conformation
  • Phosphoric Acids / chemistry
  • Phosphoric Acids / metabolism*
  • Phosphotransferases / chemistry
  • Phosphotransferases / metabolism*
  • Polysaccharides, Bacterial / chemistry
  • Polysaccharides, Bacterial / metabolism*


  • Amides
  • Phosphoric Acids
  • Polysaccharides, Bacterial
  • Glutamine
  • phosphoramidic acid
  • Phosphotransferases