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Updated: May 22, 2026

Extraction and Visualization of Protein Aggregates after Treatment of Escherichia coli with a Proteotoxic Stressor
Published on: June 29, 2021
Hydroxybutyrate prevents protein aggregation in the halotolerant bacterium Pseudomonas sp. CT13 under abiotic stress
Gabriela Soto1, Lorena Setten, Christian Lisi
1Instituto de Genética Ewald A. Favret (CICVyA-INTA), De los Reseros S/N, C25 (1712), Castelar, Provincia de Buenos Aires, Argentina.
Abstract:
Polyhydroxybutyrate (PHB), a typical carbon and energy storage compound, is widely found in Bacteria and Archae domains. This polymer is produced in response to conditions of physiological stress. PHB is composed of repeating units of β-hydroxybutyrate (R-3HB). It has been previously shown that R-3HB functions as an osmolyte in extremophile strains. In this study, Pseudomonas sp. CT13, a halotolerant bacterium, and its PHB synthase-minus mutant (phaC) were used to analyze the chaperone role of R-3HB. The production of this compound was found to be essential to salt stress resistance and positively correlated with salt concentration, suggesting that PHB monomer acts as a compatible solute in Pseudomonas sp. CT13. R-3HB accumulation was also associated with the prevention of protein aggregation under combined salt and thermal stresses in Pseudomonas sp. CT13. Physiological concentrations of R-3HB efficiently reduced citrate synthase (CS) aggregation and stabilized the enzymatic activities of CS during thermal stress. Docking analysis of the CS/R-3HB interaction predicted the stability of this complex under physiological concentrations of R-3HB. Thus, in vivo, in vitro and in silico analyses suggest that R-3HB can act as a chemical chaperone.
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