Metal Affinity Tag for Protein Expression and Purification using the Flexi Vectors

Becky Godat, Jim Hartnett, Jami English, Laurie Engel, Michael Slater, Tonny Johnson and Elaine Schenborn
Promega Corporation
Publication Date: 2005


We have developed a new metal affinity tag, HQ tag, for the purification of recombinant proteins. The HQ tag is incorporated into several Flexi® Vectors for convenient cloning and expression. Protein-coding regions can be easily and efficiently transferred into this affinity-tag vector from other Flexi® Vectors. The HQ Flexi® Vectors come in four formats to provide flexibility in tag location and antibiotic resistance. The HQ tag performs similarly to a polyhistidine tag purified from bacterial cells. However, some HQ-tagged proteins can be eluted from the affinity columns at lower concentrations of imidazole. This property of the HQ tag may be useful for downstream applications such as enzymatic reactions.

Promega Notes 91, 17–20.