Zhang, Qiang2; Jørgensen, Thomas J. D.4; Nielsen, Peter E5; Møllegaard, Niels Erik2
1 Department of Biochemistry and Molecular Biology, Faculty of Science, SDU2 unknown3 Institute of Technology and Innovation, Faculty of Engineering, SDU4 Department of Biochemistry and Molecular Biology, Faculty of Science, SDU5 Institute of Technology and Innovation, Faculty of Engineering, SDU
Most protein purification procedures include an affinity tag fused to either the N or C-terminal end of the protein of interest as well as a procedure for tag removal. Tag removal is not straightforward and especially tag removal from the C-terminal end is a challenge due to the characteristics of enzymes available for this purpose. In the present study, we demonstrate the utility of the divalent uranyl ion in a new procedure for protein purification and tag removal. By employment of a GFP (green florescence protein) recombinant protein we show that uranyl binding to a phosphorylated C-terminal tag enables target protein purification from an E. coli extract by immobilized uranyl affinity chromatography. Subsequently, the tag can be efficiently removed by UV-irradiation assisted uranyl photocleavage. We therefore suggest that the divalent uranyl ion (UO22+) may provide a dual function in protein purification and subsequent C-terminal tag removal procedures.