A multifunctional tag with the ability to benefit the expression, purification, thermostability and activity of recombinant proteins

In this study, a novel multifunctional tag, S1v1 (AEAEAHAH)2, was generated from a self-assembling amphipathic peptide in the Zuotin protein sequence by replacing lysine residues with histidine residues. After fusing S1v1 at the N-terminus through a PT-linker, the expressions of polygalacturonate lyase (PGL), lipoxygenase (LOX) and green fluorescent protein (GFP) were enhanced by 3.8, 0.2 and 1.52-fold, respectively,compared to the wild-type proteins. However, the frequently used His-tag with a PT-linker had negligible effects on expression. Moreover, the three S1v1 fusions were purified with high purities and acceptable recovery rates due to their affinity to the nickel column. In contrast, PGL and LOX fused with His-tag were unable to be adsorbed by the nickel column, and His-tag fusion only achieved 8.23% of GFP recovery in the same purification process.In addition, S1v1 fusions induced the enhancement of thermostabilties and/or activities of PGL, LOX and GFP. These results indicated that S1v1 was much more effective than the frequently used His-tag during protein expression and purification in these cases, and will be especially suitable for those proteins requiring the simultaneous enhancement of expression, production and catalytic properties.