title: Ubiquinone biosynthesis in Escherichia coli K-12. Accumulation of an octaprenol, farnesylfarnesylgeraniol, by a multiple aromatic auxotroph.
abstract: Cell extracts of a multiple aromatic auxotroph of Escherichia coli K-12, strain AB2830, grown in the absence of precursors of the quinone rings of the ubiquinone and menaquinone molecules, converted 4-hydroxy[U-(14)C]benzoate into a mixture of 3-octaprenyl-4-hydroxybenzoate and 2-octaprenylphenol. An octaprenol, farnesylfarnesylgeraniol, was isolated from such cell extracts and characterized by n.m.r. and mass spectroscopy. Neither the octaprenol, nor polyprenylation of 4-hydroxy[U-(14)C]benzoate, could be detected in cell extracts of strain AB2830 grown in the presence of 0.1mm-4-hydroxybenzoate. It was concluded that, in the biosynthesis of ubiquinone, the polyprenyl side chain is added to 4-hydroxybenzoate as a C(40) unit, the active form of which is converted by cell extracts into farnesylfarnesylgeraniol. The multiple aromatic auxotroph, when grown in the absence of 4-hydroxybenzoate but in the presence of 4-aminobenzoate, converted the latter compound into 3-octaprenyl-4-aminobenzoate. This compound was isolated from whole cells and characterized by n.m.r. and mass spectroscopy.
mesh_terms: D000438:Alcohols / Q000378:metabolism; D062365:Aminobenzoates / Q000378:metabolism; D001565:Benzoates / Q000378:metabolism; D002247:Carbon Isotopes; D004926:Escherichia coli / Q000378:metabolism*; D005204:Farnesol / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D009154:Mutation; D011809:Quinones / Q000378:metabolism; D013729:Terpenes / Q000378:metabolism*; D014451:Ubiquinone / Q000096:biosynthesis* / Q000378:metabolism
chemical_list: D000438:Alcohols; D062365:Aminobenzoates; D001565:Benzoates; D002247:Carbon Isotopes; D011809:Quinones; D013729:Terpenes; D014451:Ubiquinone; D005204:Farnesol