title: Poly(3-hydroxybutyrate) (PHB) depolymerase PhaZa1 is involved in mobilization of accumulated PHB in Ralstonia eutropha H16.
abstract: The recently finished genome sequence of Ralstonia eutropha H16 harbors nine genes that are thought to encode functions for intracellular depolymerization (mobilization) of storage poly(3-hydroxybutyrate) (PHB). Based on amino acid similarities, the gene products belong to four classes (PhaZa1 to PhaZa5, PhaZb, PhaZc, and PhaZd1/PhaZd2). However, convincing direct evidence for the in vivo roles of the gene products is poor. In this study, we selected four candidate genes (phaZa1, phaZb, phaZc, and phaZd1) representing the four classes and investigated the physiological function of the gene products (i) with recombinant Escherichia coli strains and (ii) with R. eutropha null mutants. Evidence for weak but significant PHB depolymerase activity was obtained only for PhaZa1. The physiological roles of the other potential PHB depolymerases remain uncertain.
authors.affiliation: Institut für Mikrobiologie, Universität Stuttgart, Allmandring 31, 70550 Stuttgart, Germany.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Uchino
authors.forename: Terumi
authors.initials: T
authors.lastname: Saito
authors.forename: Dieter
authors.initials: D
authors.lastname: Jendrossek
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000378:metabolism*; D015153:Blotting, Western; D002265:Carboxylic Ester Hydrolases / Q000235:genetics* / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D020118:Cupriavidus necator / Q000201:enzymology* / Q000378:metabolism; D004926:Escherichia coli; D005947:Glucose / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008856:Microscopy, Fluorescence
chemical_list: D002265:Carboxylic Ester Hydrolases; D005947:Glucose; D020155:3-Hydroxybutyric Acid