Expression and extensive characterization of a beta-glycosidase from the extreme thermoacidophilic archaeon Sulfolobus solfataricus in Escherichia coli: authenticity of the recombinant enzyme.

The gene coding for the beta-glycosidase from the archaeon Sulfolobus solfataricus has been overexpressed in Escherichia coli. The enzyme was purified to homogeneity with a rapid purification procedure employing a thermal precipitation as a crucial step. The final yield was 64% and the purification from the thermal precipitation was 5.4-fold. The expressed enzyme shows the same molecular mass, thermophilicity, thermal stability, and broad substrate specificity, with noticeable exocellobiase (glucan 1,4-beta-D-glucosidase) activity, of the enzyme purified from S. Solfataricus. We provide evidence that the beta-glycosidase can assume its functional state in E. coli without the contribution of N-epsilon-methylated lysine residues.