UNIT 26.4 Recombinant Protein Purification by Self-Cleaving Elastin-like Polypeptide Fusion Tag

Abstract

This unit presents a rapid and simple method for the nonchromatographic purification of recombinant proteins expressed in E. coli. This method relies on a thermally responsive elastin-like polypeptide (ELP) tag, where the tagged protein is precipitated using a mild temperature shift. The tag is then induced to self-cleave by a mild pH shift and is subsequently removed by a final thermal precipitation. The result is a purified native protein target, without the requirement for affinity apparatus or protease removal of the tag. This protocol describes the required cloning methods to insert a given target into the expression vector, as well as the general method for purifying the resulting expressed protein. Curr. Protoc. Protein Sci. 58:26.4.1-26.4.18. © 2009 by John Wiley & Sons, Inc.