Supramolecular organization of elastin and elastin-related nanostructured biopolymers

The ultrastructure of elastin has been extensively analyzed by different methodologies. Starting from the first descriptions, where elastin was depicted as an amorphous structure, more complex and, in some cases, varied morphologies were revealed. The supramolecular structures found for elastin have been compared with those found for other elastin-related polypeptides, such as alpha-elastin and tropoelastin, and very similar features emerged. This review will deal with the supramolecular organization exhibited by many elastin-related compounds, starting from elastin, going through polypeptides constituted by different domains of tropoelastin, up to polymers containing repetitive sequences of elastin. In particular, recent developments on biopolymers of general type poly(Val-Pro-Gly-Xaa-Gly) and poly(Xaa-Gly-Gly-Zaa-Gly) (Xaa, Zaa = Val, Leu, Lys, Glu, Orn) obtained either by chemical synthesis or recombinant DNA techniques will be discussed in detail. The general aim is to describe the supramolecular features useful for the identification of elastin-inspired nanostructured biopolymers for developing highly functional and biocompatible vascular grafts as well as scaffolds for tissue regeneration.