(113f) Chromatographic Refolding of Proteins

Protein expression in E. coli often results in the formation of a kind of protein aggregate called inclusion body. Conversion of the inactive protein aggregate into biologically active protein is a key step in production of recombinant products. Conventional dilution refolding technique suffers from disadvantages of low recovery and low concentration. Over the last few years, various chromatographic refolding techniques have been developed in several labs including the author's one. Chromatography has been a very successful technique in protein separation and purification. Like in protein separation and purification, chromatographic refolding also utilizes the solid media in a similar way, but the media act as a kind of chaperone or assistant to help the protein refolding in a correct way, which minimizes the misfolding and aggregation. The feed solution containing denatured protein and denaturant is loaded onto the column. Renaturation buffers are introduced to elute the denatured protein to move through the column. During this process, simultaneous refolding and adsorption take place. The solid phase helps the correct folding of the protein. At the column outlet, the protein exits in correct form. A successful strategy is the use of gradient elution in chromatographic refolding which provides a gentle and gradual change of the solution environment for the protein to refold. The gradient refolding could minimize misfolding and aggregation which are induced by sudden change of the solution in conventional refolding operation.