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Polyhydroxybutyrate (PHB) granules, also designated as carbonosomes, are supra-molecular complexes in prokaryotes consisting of a PHB polymer core and a surface layer of structural and functional proteins. The presence of suspected phospholipids in the surface layer is based on in vitro data of isolated PHB granules and is often shown in cartoons of the PHB(More)
The putative physiological functions of two related intracellular poly(3-hydroxybutyrate) (PHB) depolymerases, PhaZd1 and PhaZd2, of Ralstonia eutropha H16 were investigated. Purified PhaZd1 and PhaZd2 were active with native PHB granules in vitro. Partial removal of the proteinaceous surface layer of native PHB granules by trypsin treatment or the use of(More)
A protein (PhaX) that interacted with poly(3-hydroxybutyrate) (PHB) depolymerase PhaZa1 and with PHB granule-associated phasin protein PhaP2 was identified by two-hybrid analysis. Deletion of phaX resulted in an increase in the level of polyphosphate (polyP) granule formation and in impairment of PHB utilization in nutrient broth-gluconate cultures. A(More)
Identification of proteins that were present in a polyhydroxybutyrate (PHB) granule fraction isolated from Ralstonia eutropha but absent in the soluble, membrane, and membrane-associated fractions revealed the presence of only 12 polypeptides with PHB-specific locations plus 4 previously known PHB-associated proteins with multiple locations. None of the(More)
We investigate transport properties of model polyelectrolyte systems at physiological ionic strength (0.154 M). Covering a broad range of flow length scales-from diffusion of molecular probes to macroscopic viscous flow-we establish a single, continuous function describing the scale dependent viscosity of high-salt polyelectrolyte solutions. The data are(More)
A Rhodospirillum rubrum gene that is predicted to code for an extracellular poly(3-hydroxybutyrate) (PHB) depolymerase by the recently published polyhydroxyalkanoates (PHA) depolymerase engineering database was cloned. The gene product (PhaZ3 Rru ) was expressed in recombinant E. coli, purified and biochemically characterized. PhaZ3 Rru turned out, however,(More)
The ubiquitin-proteasome system is essential for maintaining a functional cell. Not only does it remove incorrectly folded proteins, it also regulates protein levels to ensure their appropriate spatial and temporal distribution. Proteins marked for degradation by the addition of Lys(48)-linked ubiquitin (Ub) chains are recognized by shuttle factors and(More)
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