title: Diverse protein regulations on PHA formation in Ralstonia eutropha on short chain organic acids.
abstract: Organic acids are considered as potential substrates for biosynthesis of polyhydroxyalkaonates. The acids may also be the metabolic inhibitors at moderate concentration levels. In this study, Ralstonia eutropha was used to elucidate the protein regulations when the bacterial cells pre-cultivated on glucose were exposed to three representative short chain organic acids, acetic, propionic and levulinic acids. The research compared and examined the proteins that might participate in PHA metabolism, primary metabolism, and cell's defense systems. A number of proteins were found to be induced in R. eutropha by using 1D-PAGE and nano-liquid chromatography tandem MS/MS. With the proteins being up-regulated, a dramatic change occurred in the induction of PHA metabolism, including fatty acid biosynthesis for acetate, beta-oxidation for propionate and both for levulinic acid. Acetate kinase was induced in response to the presence of acetate or levulinic acid. The organic acids induced several proteins involved in amino acid biosynthesis, purine and pyrimidine biosynthesis, and cofactor biosynthesis in R. eutropha, but the regulations had a great variation. R. eutropha might employ different regulation mechanisms to maintain cell growth and PHA formation when the cells are exposed to the organic acids as sole source of carbon and energy.
authors.affiliation: Dapartment of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
authors.forename: Sung-Eun
authors.initials: SE
authors.lastname: Lee
authors.forename: Qing X
authors.initials: QX
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Yu
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D000429:Alcohol Oxidoreductases / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D002264:Carboxylic Acids / Q000378:metabolism*; D020118:Cupriavidus necator / Q000378:metabolism*; D030562:Databases, Protein; D004591:Electrophoresis, Polyacrylamide Gel; D004734:Energy Metabolism; D005227:Fatty Acids / Q000096:biosynthesis; D007982:Levulinic Acids / Q000378:metabolism; D010084:Oxidation-Reduction; D054813:Polyhydroxyalkanoates / Q000378:metabolism*; D011422:Propionates / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D001426:Bacterial Proteins; D002264:Carboxylic Acids; D005227:Fatty Acids; D007982:Levulinic Acids; D054813:Polyhydroxyalkanoates; D011422:Propionates; D000429:Alcohol Oxidoreductases; C023744:acetoacetyl-CoA reductase; C029658:propionic acid; D019342:Acetic Acid; C032246:levulinic acid