Abstract:

Elastin-like polypeptides（ELP）are an elastic and temperature-sensitive synthetic protein polymer composed of a Val-Pro-Gly-Xaa-Gly repeat unit derived from human tropoelastin. ELPs undergo a sharp reversible phase transition at specific temperatures known as the inverse transition temperature（T_t）. Below its T_t,ELP assumes a random coil shape,is highly solvated and hence highly soluble in aqueous solution. However,when temperature is raised above its T_t,the ELP becomes insoluble,forms large microns and begins to aggregate. ELP-based inverse transition cycle（ITC）is a non-chromatographic technique for the separation and purification of recombinant protein. Using the reversible phase change characteristics of ELP fusion proteins,ELP-labeled fusion proteins are specifically isolated from soluble protein supernatant after multiple ITC cycles. This technique requires only conventional centrifuges to obtain the target protein of the same purity as that by affinity chromatography,and it is low cost,easy to operate and suitable for lage-scale production. ELP and ELP-derived molecules present properties of fine elasticity,self-assembly,long-term stability and biological activity. The precise control in designing ELP is conducive to manipulating their stimulation responses to the external environment and other physical functional characteristics. The adjustable physical and chemical properties of ELP and its promising biocompatibility make ELP widely used in biotechnology. In this paper,the phase transition characteristics and mechanism of ELP,the design of ELP fusion protein and the effect of ELP to fusion proteins（peptides）are reviewed. Meanwhile,the application of ELP tag in protein purification,biomedicine and bioengineering,hydrogels and emerging fields is reviewed. Finally,the research directions and key issues and technologies of ELP also are discussed.

Key words: elastin-like polypeptide, ITC technology, ELP tag, protein purification, biological application