Solving the structure of nature’s elasticity stretches the possibilities for engineering flexible materials.
Baldock C, Oberhauser AF, Ma L, Lammie D, Siegler V, Mithieux SM, Tu Y, Chow JY, Suleman F, Malfois M, Rogers S, Guo L, Irving TC, Wess TJ, Weiss AS.(2011) Shape of tropoelastin, the highly extensible protein that controls human tissue elasticity. PNAS 108, 4322-7. PNAS
The shape of the protein that gives human tissues their elastic properties has been defined. It revealed that once again evolution has triumphed where engineering has so far failed; by generating a molecule with near-perfect elasticity that will last a lifetime.
All mammals rely on “Elastin” to provide their tissues with the ability to stretch and then return to their original shape. Lungs expand with each intake of breath and elastically contract on exhalation. Even more impressive is the constant expansion and contraction of arteries over the course of a billion heart beats. This high level of physical performance demanded of Elastin vastly exceeds and indeed outlasts all human-made elastics.
The main component of Elastin is a protein called “Tropoelastin”. It is the co-ordinated assembly of many Tropoelastins into Elastin that gives tissues their stretchy properties. This exquisite assembly helps to generate elastic tissues as diverse as artery, lung and skin.
Using state-of-the-art techniques, an international team of scientists from the UK, USA and Australia has solved the structure of Tropoelastin. Tropoelastin is a curved, spring-like molecule with a “foot” region to facilitate attachment to cells. Stretching and relaxing experiments showed that Tropoelastin had the extraordinary capacity to extend to 8-times its initial length. It can then return to its original shape with no loss of energy, making it a near-perfect spring.
Elastics are used in applications as diverse as clothing, vehicles, tissue engineering and even space travel. Thus, understanding how the structure of Tropoelastin creates its exceptional elastic properties will hopefully enable the development of synthetic “Elastin-like” polymers with potentially wide-ranging benefits.