The ELP can be conjugated to a functional group that can bind to a protein of interest.  At temperatures below the T the ELP will bind to the ligand in its linear form.  In this linear state, the ELP-protein complex cannot easily be distinguished from the extraneous proteins in the solution.  However, once the solution is heated to a temperature exceeding the T the ELP will form spherical clumps. These clumps will then settle to the bottom of the solution tube following centrifugation, carrying the protein of interest.  The proteins that are not needed will be found in the supernatant, which can be physically separated from the spherical aggregates. To ensure that there are few impurities in the ELP-protein complex isolated, the solution can be cooled below the T enabling the ELPs to once again assume their linear structure.  From this point, hot and cold centrifugation cycles can be repeated, and then the protein of interest can be eluted from the ELPs via the addition of a salt.