Science / Discoveries

Water Drives Elastin's Stretch, Simulations Show

A 60-microsecond atom-by-atom model weighs a decades-old argument: the water surrounding elastin contributes more to its recoil than the protein's own flexibility.

Sloane MercerAI editorial voice · 1 min read

Elastin fibers imaged in tissue. The UConn work modeled elastin's building block, tropoelastin, one molecule region at a time. (Howard Vindin, CC BY-SA 4.0)

Summary

UConn simulations found the water around elastin, not the protein's own flexibility, makes the dominant contribution to how tissue stretches and recoils.

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Water, more than the protein itself, does the work when elastin stretches, according to atom-by-atom simulations from the University of Connecticut. [UConn researchers uncover water's critical role in human tissue elasticity — UConn Today]

Anna Tarakanova and Metehan Çam modeled a 225-amino-acid region of human tropoelastin, elastin's building block, and tracked it for 60 microseconds of simulated time. Stretching exposed more of the protein to water, and the water's lost freedom drove the recoil. [UConn researchers uncover water's critical role in human tissue elasticity — UConn Today]

Elastin is the protein that lets skin, arteries and lung tissue stretch and snap back, and why it recoils has been argued for decades — the protein's own flexibility against the behavior of the water around it. The UConn team, at the College of Engineering, built the model atom by atom and ran it on the Anton 3 supercomputer at the Pittsburgh Supercomputing Center, made available by D.E. Shaw Research, comparing a relaxed state against a fully extended reference state. [UConn researchers uncover water's critical role in human tissue elasticity — UConn Today]

The mechanism they found is a water trap. As the protein stretches, more of its surface is exposed, and additional water molecules are drawn into a thin layer around it where they have less freedom of movement than water farther away. When the protein relaxes, some of those molecules return to the surrounding liquid and regain their freedom. "The protein's flexibility still matters, but hydration water makes the dominant contribution to the entropy changes we measured," said Çam, a postdoctoral researcher working with Tarakanova, an associate professor. [UConn researchers uncover water's critical role in human tissue elasticity — UConn Today]

The limits are the method's. This is a simulation of one 225-amino-acid region of the precursor protein, not a measurement of whole tissue, and it builds on earlier evidence for a water-driven mechanism rather than settling the debate outright. What it adds is a measurement the flexibility-only account has to answer: in the model, the water's entropy change is the bigger term. The study is published in Nature Communications. [UConn researchers uncover water's critical role in human tissue elasticity — UConn Today]

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