title: Pathway for ubiquinone biosynthesis in Escherichia coli K-12: gene-enzyme relationships and intermediates.
abstract: Seven ubiquinone-deficient mutants of Escherichia coli, each of which accumulates two phenolic precursors of ubiquinone, have been characterized, and the accumulated compounds have been identified. The mutants accumulate small quantities of 2-octaprenyl-6-methoxyphenol, which was isolated and characterized by nuclear magnetic resonance and mass spectrometry, and relatively large amounts of 2-octaprenylphenol, a compound previously identified from E. coli. They also accumulate small quantities of a compound identified as 2-(hydroxyoctaprenyl)phenol although the relevance of this compound to the biosynthesis of ubiquinone is not clear. The results of genetic analysis suggest that each of the mutants carries a mutation in a gene (designated ubiH) which is located at about min 56 on the E. coli chromosome and is co-transducible with the serA and lysB genes. Based on information obtained from this and previous studies with ubiquinone-deficient mutants, a pathway is proposed for ubiquinone biosynthesis in E. coli, and a summary of the known gene-enzyme relationships is given.
mesh_terms: D002855:Chromatography, Thin Layer; D002874:Chromosome Mapping; D004926:Escherichia coli / Q000201:enzymology* / Q000254:growth & development / Q000378:metabolism; D005796:Genes; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D009154:Mutation; D010636:Phenols / Q000032:analysis / Q000302:isolation & purification; D014451:Ubiquinone / Q000032:analysis / Q000096:biosynthesis* / Q000302:isolation & purification; D014753:Vinyl Compounds / Q000302:isolation & purification
chemical_list: D010636:Phenols; D014753:Vinyl Compounds; D014451:Ubiquinone