title: A direct comparison of approaches for increasing carbon flow to aromatic biosynthesis in Escherichia coli.
abstract: Different approaches to increasing carbon commitment to aromatic amino acid biosynthesis were compared in isogenic strains of Escherichia coli. In a strain having a wild-type PEP:glucose phosphotransferase (PTS) system, inactivation of the genes encoding pyruvate kinase (pykA and pykF) resulted in a 3.4 fold increase in carbon flow to aromatic biosynthesis. In a strain already having increased carbon flow to aromatics by virtue of overexpression of the tktA gene (encoding transketolase), the pykA and/or pykf mutations had no effect. A PTS- glucose+ mutant showed a 1.6-fold increase in carbon flow to aromatics compared to the PTS+ control strain. In the PTS- glucose+ host background, overexpression of tktA caused a further 3.7-fold increase in carbon flow, while inactivation of pykA and pykF caused a 5.8-fold increase. When all of the variables tested (PTS-glucose+, pykA, pykF, and overexpressed tktA) were combined in a single strain, a 19.9-fold increase in carbon commitment to aromatic biosynthesis was achieved.
authors.affiliation: Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México.
authors.forename: G
authors.initials: G
authors.lastname: Gosset
authors.forename: J
authors.initials: J
authors.lastname: Yong-Xiao
authors.forename: A
authors.initials: A
authors.lastname: Berry
mesh_terms: D000596:Amino Acids / Q000096:biosynthesis*; D002244:Carbon / Q000378:metabolism*; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism*; D005798:Genes, Bacterial / Q000235:genetics; D009154:Mutation; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000502:physiology; D011770:Pyruvate Kinase / Q000235:genetics; D013400:Sugar Acids / Q000378:metabolism; D014174:Transketolase / Q000235:genetics
chemical_list: C017182:5-dehydro-3-deoxy-D-arabino-heptulosonic acid-7-phosphate; D000596:Amino Acids; D013400:Sugar Acids; D002244:Carbon; D014174:Transketolase; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; D011770:Pyruvate Kinase