Isolation, Purification, and Properties of a Novel Small Heat Shock Protein from the Hyperthermophile Sulfolobus solfataricus

Abstract

The isolation, purification, and properties of a putative small heat shock protein (sHsp), named SsHSP14.1, from the hyperthermophilic archaeon Sulfolobus solfataricus have been investigated. The sHsp was successfully expressed and purified from Escherichia coli. In vivo chaperone function of SsHSP14.1 for preventing aggregation of proteins during heating was investigated. It was found that recombinant SsHSP14.1 with a molecular mass of 17.8 kDa prevented E. coli proteins from aggregating in vivo at 50 degrees C. This result suggested that SsHSP14.1 confers a survival advantage on mesophilic bacteria by preventing protein aggregation at supraoptimal temperatures. In vitro, the purified SsHSP14.1 protein was able to prevent Candida antarctica lipase B from aggregation for up to 60 min at 80 degrees C. Moreover, the SsHSP14.1 enhanced thermostability of bromelain extending its half-life at 55 degrees C by 67%.