Elastin lubrication

Elastin is not a true rubber as it is not self-lubricating. It has elastic properties only in the presence of water. At rest, elastin is tightly folded, stabilized by hydrophobic interactions between nonpolar residues this has been termed an oiled coil. On stretching, these hydrophobic interactions are broken, and the nonpolar residues are exposed to water. This conformation is thermodynamically unstable, and once the stretching force is removed, the elastin recoils to its resting state. 

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