PurF-independent phosphoribosyl amine formation in yjgF mutants of Salmonella enterica utilizes the tryptophan biosynthetic enzyme complex anthranilate synthase-phosphoribosyltransferase

J Bacteriol. 2006 Oct;188(19):6786-92. doi: 10.1128/JB.00745-06.


In Salmonella enterica, the biosynthetic pathways for the generation of purines and the essential cofactor thiamine pyrophosphate branch after sharing five enzymatic steps. Phosphoribosyl amine (PRA) is the first intermediate in the common portion of the pathway and is generated from phosphoribosylpyrophosphate and glutamine by the PurF enzyme (phosphoribosylpyrophosphate amidotransferase). A null mutation in yjgF allows PurF-independent PRA formation by an unknown mechanism. The tryptophan biosynthetic enzyme complex anthranilate synthase-phosphoribosyltransferase, composed of the TrpD and TrpE proteins, was shown to be essential for PRA formation in strains lacking both yjgF and purF. The activity generating PRA in a yjgF mutant background has features that distinguish it from the TrpDE-mediated PRA formation shown previously for this enzyme in strains with an active copy of yjgF. The data presented here are consistent with a model in which the absence of YjgF uncovers a new catalytic activity of TrpDE.

Publication types

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

MeSH terms

  • Anthranilate Phosphoribosyltransferase / genetics
  • Anthranilate Phosphoribosyltransferase / physiology*
  • Anthranilate Synthase / genetics
  • Anthranilate Synthase / physiology*
  • Bacterial Proteins / genetics
  • Gene Deletion
  • Models, Biological
  • Mutagenesis, Insertional
  • Ribosemonophosphates / biosynthesis*
  • Salmonella typhimurium / enzymology*
  • Salmonella typhimurium / growth & development
  • Salmonella typhimurium / metabolism*


  • Bacterial Proteins
  • Ribosemonophosphates
  • YjgF protein, Salmonella typhimurium
  • phosphoribosylamine
  • Anthranilate Phosphoribosyltransferase
  • Anthranilate Synthase