Mechanism of resilin elasticity

Abstract

Resilin is critical in the flight and jumping systems of insects as a polymeric rubber-like protein with outstanding elasticity. However, insight into the underlying molecular mechanisms responsible for resilin elasticity remains undefined. Here we report the structure and function of resilin from Drosophila CG15920. A reversible beta-turn transition was identified in the peptide encoded by exon III and for full length resilin during energy input and release, features that correlate to the rapid deformation of resilin during functions in vivo. Micellar structures and nano-porous patterns formed after beta-turn structures were present via changes in either the thermal or mechanical inputs. A model is proposed to explain the super elasticity and energy conversion mechanisms of resilin, providing important insight into structure-function relationships for this protein. Further, this model offers a view of elastomeric proteins in general where beta-turn related structures serve as fundamental units of the structure and elasticity.

The role of mechanics in biological and bio-inspired systems

“…Other mechanofunctionalities are informed by materials with high elastic energy storage capacity with minimal dissipation, such as resilin and elastin (Fig. 2b), where largely disordered, hydrated, networks of biomolecules constitute the nanostructure 17 . Beta-sheet domains in silk (Fig.…”

“…These overarching mechanical properties are tied more strongly to structure than sequence, as a number of sequences preserving a few key features can form identical secondary structures that serve as the foundation for embedding targeted mechanofunctions (energy dissipation, extensibility, strength and so on) in synthetic applications. One class of synthetic materials that utilizes these structural features is high-resilience rubber formed from crosslinked resilin 17,18 whose molecular and hierarchical structure promotes large energy storage. This material property allows locusts to jump to distances much greater than their size, and enables effective energy storage in the hinges of dragonfly wings.…”

“…Recent efforts in realizing synthetic bio-based technologies have led to many successes in mimicking passive material properties that require no energy expenditures, such as adhesion 51 , elasticity 17 , strength and toughness 52 , self-healing 53 and stimuli responsiveness 54 . In addition, many active, biomimetic systems that do utilize energy to carry out their mechanical functions have also been produced, including synthetic bio-actuators 55 , contractile polymers 56 and electrospun climbing fibres 56 .…”

“…Elastomeric protein-based biomaterials are one such example in which elastic proteins (that is, elastin, resilin and so on) can be assembled into various forms (hydrogels, films and scaffolds) or further combined with a synthetic polymer to form new biomaterials 17,80,81 . In these recombinant approaches, the inherent properties of biomolecules are used in applications that can vary significantly from those observed in nature.…”

Engineering materials from proteins

“…80 However, it has recently been proposed that a reversible b-turn transition in exon III is responsible for the superelastic properties of the material. 81 Because of its properties, resilin has attracted significant interest for engineering artificial protein analogues, and several minimal sequences have been developed. These are actively being investigated for the development of new biomaterials, 82 where the minimal sequences are able to produce hydrogels with a relatively high resilience.…”