Elastin like polypeptides

Elastin-like polypeptides (ELPs) are artificial protein polymers composed of pentapeptide Val–Pro–Gly–Xaa–Gly. In this motif Xaa (so called "guest residue") can be any amino acid except proline. ELPs are able to undergo reversible phase transition induced by pH, temperature or ionic strength. This behavior is dependent on the transition temperature (T_t) of a given ELP construct. T_t is primarily affected by relative hydrophobicity or hydrophilicity of an ELP. The more hydrophobic the ELP (whether by guest residue or fusion to other non-ELP modules), the lower the T_t. Molecular weight and concentration also affect the transition temperature, where the T_t decreases with increasing molecular weight or concentration. These polymers are soluble at a temperature below the T_t, but insoluble when the temperature exceeds T_t, making them very useful for simple purification (ITC). ELPs are useful in medicine (e.g. cancer therapy, regenerative medicine) or recombinant proteins purification.