title: Biosynthesis of aromatic compounds: 13C NMR spectroscopy of whole Escherichia coli cells.
abstract: 13C and 31P NMR spectra of wild-type Escherichia coli showed resonances from metabolic intermediates of glycolysis and ATP formation but no detectable signals from aromatic amino acids. However, tyrosine biosynthesis from D-[l-13C]glucose was observed in cells harboring a feedback-resistant allele of aroF, the gene encoding tyrosine-sensitive 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase [7-phospho-2-keto-3-deoxy-D-arabino-heptonate D-erythrose-4-phosphate-lyase (pyruvate-phosphorylating), EC4.1.2.15], one of the isoenzymes that control carbon flow through the common aromatic biosynthetic pathway. A similar accumulation of tyrosine and phenylalanine is seen in cells carrying a multiple-copy plasmid that carries a wild-type aroF allele in addition to pheA and tyrA, the structural genes for controlling enzymes of the terminal pathways to phenylalanine and tyrosine biosynthesis. These in vivo measurements by a noninvasive probe suggest feedback inhibition as the quantitatively major mechanism controlling carbon flow in the common aromatic compound biosynthetic pathway. In strains accumulating aromatic amino acids, a transient accumulation of trehalose was detected, indicating that previously unknown changes in Escherichia coli metabolism accompany overproduction of aromatic compounds.
mesh_terms: D010723:3-Deoxy-7-Phosphoheptulonate Synthase / Q000235:genetics*; D000446:Aldehyde-Lyases / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005246:Feedback; D005796:Genes; D005798:Genes, Bacterial; D005838:Genotype; D009682:Magnetic Resonance Spectroscopy; D010641:Phenotype; D013045:Species Specificity; D014443:Tyrosine / Q000096:biosynthesis*
chemical_list: D014443:Tyrosine; D010723:3-Deoxy-7-Phosphoheptulonate Synthase; D000446:Aldehyde-Lyases