polyhydroxyalkanoate granule

Edge evidence

• polyhydroxyalkanoate located in polyhydroxyalkanoate granule biolink:located_in

  PHA polymer accumulates inside cytoplasmic granules.

  • DOI:10.1128/mr.54.4.450-472.1990 Anderson & Dawes describe PHAs (chiefly PHB) as carbon/energy reserves stored as cytoplasmic granules.
• polyhydroxyalkanoate granule enables carbon and energy storage RO:0002327

  PHA granules realize the carbon/energy storage function.

  • DOI:10.1038/s41579-020-0413-0 Greening & Lithgow include PHA bodies among bacterial intracellular organelles.
• nutrient limitation / high C:N ratio increases polyhydroxyalkanoate accumulation RO:0002213

  High C/N ratio and N/S/P depletion stimulate PHA accumulation.

  • DOI:10.3390/molecules29102293 PHA accumulation is stimulated by a high C/N ratio, depletion of N, S, and P, or a low rate of respiration.
• nutrient limitation / high C:N ratio induces polyhydroxyalkanoate accumulation

  Nutrient limitation with excess carbon induces PHA accumulation.

  • DOI:10.1016/j.jbc.2024.107523 Environmental triggers include nutrient limitation and excess carbon that induce PHA accumulation.
• PHA synthase (PhaC) catalyzes polyhydroxyalkanoate biolink:catalyzes

  PhaC polymerizes hydroxyacyl-CoA into PHA/PHB polymer.

  • DOI:10.3390/polym15143027 PhbC polymerizing beta-hydroxybutyryl-CoA into PHB.
• phasin (PhaP) stabilizes polyhydroxyalkanoate

  Phasins coat and stabilize PHB chains at the granule surface.

  • DOI:10.3390/polym15143027 Phasins are GAPs that coat and stabilize PHB chains.
• phasin (PhaP) controls PHB granule size and number RO:0002211

  Phasins control the size and number of PHB granules.

  • DOI:10.3390/polym15143027 Phasins control the size of the PHB granules.
• PhaR regulator represses transcription of phaP gene

  PhaR binds phaP promoters and represses transcription.

  • DOI:10.1016/j.jbc.2024.107523 PhaR is a transcriptional repressor that binds phaP promoters and represses their transcription.
• PHA depolymerase (PhaZ) mediates PHB mobilization

  PHB depolymerase cleaves PHB to 3-hydroxybutyrate, mediating mobilization.

  • DOI:10.3390/polym15143027 PHB mobilization involves a PHB depolymerase (PhbZ/PhaZ) that cleaves PHB to beta-hydroxybutyrate.
• carbon starvation triggers PHB degradation

  Starvation or exogenous carbon depletion triggers PHB degradation.

  • DOI:10.3390/polym15143027 PHB is degraded during starvation/exogenous carbon depletion or stationary phase.