The oligomeric plasticity of Hsp20 of Sulfolobus acidocaldarius protects environment-induced protein aggregation and membrane destabilization

Publication date: Available online 7 September 2018Source: Biochimica et Biophysica Acta (BBA) - BiomembranesAuthor(s): Mousam Roy, Sayandeep Gupta, Somi Patranabis, Abhrajyoti GhoshAbstractSmall heat shock proteins (sHsps) are a ubiquitous family of molecular chaperones that rescue misfolded proteins from irreversible aggregation during cellular stress. Many such sHsps exist as large polydisperse species in solution, and a rapid dynamic subunit exchange between oligomeric and dissociated forms modulates their function under a variety of stress conditions. Here, we investigated the structural and functional properties of Hsp20 from thermoacidophilic crenarchaeon Sulfolobus acidocaldarius. To provide a framework for investigating the structure-function relationship of Hsp20 and understanding its dynamic nature, we employed several biophysical and biochemical techniques. Our data suggested the existence of a ~24-mer of Hsp20 at room temperature (25 °C) and a higher oligomeric form at the higher temperature (50 °C–70 °C) and lower pH (3.0–5.0). To our surprise, we identified a dimeric form of protein as the functional conformation in the presence of aggregating substrate proteins. The hydrophobic microenvironment mainly regulates the oligomeric plasticity of Hsp20, and it plays a key role in the protection of stress-induced protein aggregation. In Sulfolobus sp., Hsp20, despite being a non-secreted protein, has been reported to be present in secretory vesicles and i...
Source: Biochimica et Biophysica Acta (BBA) Biomembranes - Category: Biochemistry Source Type: research