The structures of elastins and their function

Elastin structures and their significance towards elastic recoil properties have been reviewed. Starting from the initial hypothesis that elastin conf ormation is conditioned by that of its monomer, the structure of tropoelast in was first described using theoretical and experimental methods and a bet a class folding type was evidenced for the isolated unbound tropoelastin mo lecules. The structure of elastin in the solid state was consistent with th at of its monomer and consequently, fibrous elastin appeared constituted of globular tropoelastin molecules. Finally, theoretical and experimental con siderations have led us to the conclusion that the functional form of the e lastomer, water swollen elastin, could be a triphasic system comprising the protein chains, hydration water and solvent water. Following this descript ion, the dynamic structural equilibria occurring within elastin hydrophobic domains and the plastisizing effect of water could explain elastin elastic ity, in keeping with a classical entropic mechanism. (C) 1999 Societe franc aise de biochimie et biologie moleculaire / Editions scientifiques et medic ales Elsevier SAS.