Resilin

Resilin is an elastomeric protein found in many insects and other arthropods. It provides soft rubber-elasticity to mechanically active organs and tissue; for example, it enables insects of many species to jump or pivot their wings efficiently. Resilin was first discovered by Torkel Weis-Fogh in locust wing-hinges. Resilin is currently the most efficient elastic protein known (Elvin et al., 2005). The elastic efficiency of the resilin isolated from locust tendon has been reported to be 97% (only 3% of stored energy is lost as heat). It does not have any regular structure but its randomly coiled chains are crosslinked by di- and tri-tyrosine links at the right spacing to confer the elasticity needed to propel some jumping insects distances up to 38 times their length (as found in fleas). Resilin must last for the lifetime of adult insects and must therefore operate for hundreds of millions of extensions and contractions; its elastic efficiency ensures performance during the insect's lifetime. Resilin exhibits unusual elastomeric behavior only when swollen in polar solvents such as water. In 2005, a recombinant form of the resilin protein of the fly Drosophila melanogaster was synthesized by expressing a part of the fly gene in the bacterium Escherichia coli. Active studies are investigating potential application of recombinant resilins in biomedical engineering and medicine.