Elastin-like polypeptides as a promising family of genetically-engineered protein based polymers

Abstract

Elastin-like polypeptides (ELP) are artificial, genetically encodable biopolymers, belonging to elastomeric proteins, which are widespread in a wide range of living organisms. They are composed of a repeating pentapeptide sequence Val-Pro-Gly-Xaa-Gly, where the guest residue (Xaa) can be any naturally occurring amino acid except proline. These polymers undergo reversible phase transition that can be triggered by various environmental stimuli, such as temperature, pH or ionic strength. This behavior depends greatly on the molecular weight, concentration of ELP in the solution and composition of the amino acids constituting ELPs. At a temperature below the inverse transition temperature (Tt), ELPs are soluble, but insoluble when the temperature exceeds Tt. Furthermore, this feature is retained even when ELP is fused to the protein of interest. These unique properties make ELP very useful for a wide variety of biomedical applications (e.g. protein purification, drug delivery etc.) and it can be expected that smart biopolymers will play a significant role in the development of most new materials and technologies. Here we present the structure and properties of thermally responsive elastin-like polypeptides with a particular emphasis on biomedical and biotechnological application.

Fig. 1

The scheme describing the structure of ELPs [V₅A₂G₃-100] (Valiaev et al. , modified)

Fig. 2

The ELP aggregation mechanism (Rodriguez-Cabello et al. , modified)

Fig. 3

The scheme of the reaction of ELP cross-linking with the use of transglutaminase (McHale et al. , modified)

Fig. 4

The scheme of protein purification in inverse transition cycling (ITC) (Urry and Pattanaik , modified)

Fig. 5

The schematic representation of heavy metal removal process with application of ELP (Kostal et al. , modified)