Purification of Microbially Expressed Recombinant Proteins via a Dual ELP Split Intein System

Fusions of elastin-like peptide (ELP) purification tags and self-cleaving inteins provide a powerful platform for purifying tagless recombinant proteins without the need for conventional packed-bed columns. A drawback to this method has been premature cleaving of the ELP tag during expression, before the purification procedure can take place. Here we demonstrate a split-intein method, where the self-cleaving intein is divided into two inactive segments during expression and purification. Spontaneous assembly of the purified intein segments then restores self-cleaving activity to deliver the tagless target protein.