Biophysical and structural characterization of the small heat shock protein HspA from Thermosynechococcus vulcanus in 2 M urea

摘要: Abstract Small heat shock proteins (sHSPs) belong to the superfamily of molecular chaperones. They prevent aggregation partially unfolded or misfolded client proteins, providing protection organisms under stress conditions. Here, we report biophysical and structural characterization a small protein (HspA) from thermophilic cyanobacterium Thermosynechococcus vulcanus in presence 2 M urea. HspA has been shown be important for Photosystem II Phycobilisome antenna complex at elevated temperatures. Heterologously expressed requires 1–2 M urea maintain its solubility concentrations required most methods. Spectroscopic studies reveal β-sheet structure intactness tertiary fold HspA. In vitro assays show that maintains chaperone-like activity protecting soluble thermal aggregation. Chromatography electron microscopy exists as mixture oligomeric forms was successfully crystallized only The crystal shows urea-induced loss about 30% secondary without major alteration protein. density maps changes hydrogen bonding network which attribute demonstrates both direct interactions between functionalities surrounding solvent indirectly affect protein, are accordance with previously published studies.