Wikipedia
Abductin
Abductin is a natural elastic protein that is found in the hinge ligament of bivalve mollusks. It is unique as it is the only protein in nature with compressible elasticity. It is similar to elastin and resilin, but amino acid analysis reveals that it has high concentrations of glycine and methionine.
Abductin is made up of three prominent amino acids, glycine, methionine, and phenylalanine, which are arranged in a repeating pentapeptide sequence throughout the molecule.
It has been proposed that the protein could have uses in drug delivery or tissue engineering.