Elastin is one of the body’s most long-lasting proteins. It’s also remarkably flexible, allowing skin to stretch and twist, blood vessels to expand and relax with every heartbeat, and lungs to swell and contract with each breath. Now researchers have shed light on what gives elastin these remarkable properties by revealing how the component molecules assemble into the long chains found in tissues.
Elastin tissues comprise a protein called tropoelastin. Synchrotron imaging by Clair Baldock at the University of Manchester, UK, revealed how tropoelastin is arranged in a hierarchical structure of scissor-shaped molecules. The complex dynamics of the material as it forms large structures that can stretch and rebound were then shown through computer modelling and laboratory work involving teams from the University of Sydney, Australia, and Massachusetts Institute of Technology, US (Science Advances, doi: 10.1126/sciadv.1501145).
The dynamics are complex and surprising, says Anthony Weiss of the University of Sydney. ‘It’s almost like a dance the molecule does, with a scissors twist – like a ballerina doing a dance.’ The scissor-like appendages of one molecule lock onto the narrow end of another molecule, and this rapid process continues until it builds up long, chain-like structures. The long chains then weave together to produce the flexible tissues that make up skin, lungs and blood vessels.
While the findings relate to one particular protein and the tissues it forms, the team says the research may help in understanding a variety of other flexible biological tissues and how they work. ‘[The research] yields important insights for the design of new materials that replace those in our body, or for materials that we can use in engineering applications in which durable materials are critical,’ says Markus Buehler, head of MIT’s department of civil and environmental engineering.
‘This is fascinating work,’ says Chwee Tak Lim, professor of biomedical engineering at the National University of Singapore. ‘[It]not only enables us to better understand the requisite conditions for the formation of ‘healthy’ elastins, whether in our body or in producing them for biomaterial applications, but also provides insights into certain tissue dysfunctions arising from elastin mutations.’