Abstract
This unit presents a recombinant protein purification method that employs an elastin-like polypeptide (ELP) as a purification tag. ELPs undergo a sharp and reversible phase transition when heated above their lower critical solution temperature. ELPs retain this behavior when they are fused to a protein, and thereby provide a simple method to isolate a recombinant ELP fusion protein from cell contaminants by cycling the solution through the insoluble and soluble phase of the ELP fusion protein using a procedure that is termed Inverse Transition Cycling. This method does not require the use of chromatography, so it is cost-effective, easy to scale up, and easy to multiplex.