Expression，purification and thermal stability of heat shock protein GrpE from Streptococcus pneumonia

Abstract:

Objective：Streptococcus pneumonia is a major cause of several diseases. To express and purify the heat shock protein GrpE from Streptococcus pneumonia in order to uncover the infectious mechanism. Methods：Being amplified by PCR，the open reading frame of GrpE was subcloned into pW28 and expressed in escherichia coli（E.coli） B834. The bacterial protein was purified by nickel chro－matography column and anion-exchange chromatography column subsequently. The aggregation of GrpE in solution was analyzed by gel filtration column（Hiload Superdex 75） and its thermal stability was characterized with thermal shift assay（TSA） method. Results：The GrpE protein was expressed in E.coli B834 as soluble. The purified protein with high purity of 95.0% exhibited homodimer in solutions. The recombinant GrpE protein presented relative stabilization in a solution at pH 6.0 and 20 mmol/L NaCl. Conclusion：The GrpE protein with high purity was expressed in E.coli B834 and its thermal stability was determined with TSA method.