Molecular Biological Characteristics And Function Of Sulfolobus Solfataricus P2SHSP20

Archaea are a highly diverse and abundant group that includes many 'extremophiles'that thrive in harsh environments, such as hot sprin gs, salt lakes, and submarine volcanic habitats. Current knowledge on stress genes in archaea is considerably more limited than that for b acteria and eukaryotes. Sulfolobus solfataricus P2is a very widely s tudied crenarchaeal organism that grows well in the low pH, high sulf ur environment of volcanic hot springs. It is used as a model organis m in archaeal research to study processes such as DNA replication, ce11cycle, chromosomal integration, and RNA processin. The optimum tem perature for Sulfolobus solfataricus P2is about75℃, although it c an live between55-90℃and in a pH range of0.9-5.8, with its optim um pH being2-3. The ability of sHSPs to form oligomers contributes t o their thermal stability and ability to avoid denaturation in respon se to high temperatures. sHSPs have chaperone-like activity in vitro and protect organisms from various stresses. At denaturing temperatur es, sHSPs can prevent the aggregation of proteins by binding to, and forming a stable complex with, folding intermediates of their substra te proteins. In this study, we subcloned the coding sequence of the s mall heat shock protein, HSP20(SS02427) from the thermoacidophilic a rchaeon Sulfolobus solfataricus P2into a bacterial expression vector and produced recombinant protein for structural and functional analy sis.To investigate the level of HSP20mRNA in Sulfolobus solfataricus P2, we measured its mRNA expression profile in response to variations in culture temperature, including cold shock.E. coli transformed with HSP20was protected from a thermal stress o f50℃and cold stress of4℃. Purified S. so-HSP20behaved as a mol ecular chaperone by inhibiting the thermal aggregation of citrate syn thase and insulin B chain. These results indicate that HSP20plays an important role in the response to thermal stress. These studies may provide clues to the better understanding of the function of protein sHSP in archaea.