Construction of His sub(6)-tagging vectors allowing single-step purification of GroES and other polypeptides produced in Bacillus subtilis

Two plasmid expression vectors for Bacillus subtilis have been constructed that direct the synthesis of fusion proteins containing a stretch of six histidine residues (His sub(6)) at either the N or C terminus. The His sub(6) tag allows the rapid enrichment of proteins by metal chelate affinity chromatography in a denatured or native state. As an example of the general utility of one of these expression vectors, we produced the GroES protein encoded by the groESL operon of B. stearothermophilus.