Nature’s nanospring

International researchers have unravelled elastin – a protein which allows our lungs to expand and contract as we breathe and our arteries to dilate and constrict with our heart beat.

Elastin’s stretchy properties come from the coordinated assembly of tiny spring-like molecules called tropoelastin, and researchers from the UK, Australia and USA used state-of-the-art techniques to reveal its structure.

“Tropoelastin is a tiny protein ‘nanospring’ in the human body. Our bodies assemble these nanosprings to put elasticity into tissues like skin, blood vessels and lung,” said Tony Weiss, project leader from at the University of Sydney.

 
“We used small angle X-ray and neutron scattering to look at the shape of tropoelastin in solution,” Dr Clair Baldock from the University of Manchester told Laboratory News.

“Using different length constructs we were able to identify different regions of the tropoelastin molecule to characterise the extended spring-like N-terminal region and the C-terminal "foot" region. In addition we used atomic force microscopy to perform stretching experiments on the individual tropoelastin molecule, in order to understand how extensible it is and how easily extension is reversed.”

Their experiments showed tropoelastin has the capacity to extend to eight-times its initial length and return to its original shape with no loss of energy. Baldock believes understanding how the structure of tropoelastin creates its exceptional elastic properties will enable the development of synthetic ‘elastin-like’ polymers with wide-ranging applications and benefits.
“Understanding the extensibility of individual tropoelastin molecules has shown that elasticity resides at the molecular level, and not just in assembled cross-linked elastin  – the form found in our elastic tissues,” she told Laboratory News. “This knowledge will allow the individual tropoelastin molecule or perhaps smaller regions to be used in the development of synthetic elastic material. Professor Weiss' group in Sydney is already using tropoelastin in the design of new biomaterials.”

The researchers used I22 – the non-crystalline diffraction beamline – at the Diamond Light Source, plus the European Synchrotron Radiation Facility, the Advanced Photon Source and the neutron experiments at ISIS.
“The synchrotron technique used was biological solution scattering, and we’re currently working on improving I22’s capabilities in this area,” said Professor Nick Terrill, principal beamline scientists on I22. “We’re hoping to do a lot more of this kind of research on I22 in the future.”