Purification and functional analysis of the recombinant protein isolated from E. coli by employing three different methods of bacterial lysis

In this paper, the purification of the human recombinant protein expressed in E. coli using the GST Gene Fusion System, by applying various methods of bacterial lysis: sonication, freeze/thaw and beadbeating, is presented. The study was an attempt to compare the properties of the proteins obtained by the sonication method, recommended by manufacturers but inaccessible for many researchers, with those obtained using two other readily available lysis methods. The data show that all purified proteins were soluble and intact with the highest protein yield being obtained via the freeze/thaw method. The results of functional analysis indicate that the proteins purified using the sonication and freeze/thaw methods of lysis exhibited similar DNA binding affinity, while the protein purified by beadbeating was also functional but with a lower binding affinity. The conclusion of this study is that all three lysis methods could be successfully employed for protein purification.