Recent findings about collagen, our body’s most abundant protein, reveal that its sacrificial bonds snap more quickly than the basic structure, thereby protecting the tissue as a whole – they track down harmful radicals that are produced during mechanical stress.
One of the more unusual ways objects can increase longevity is by sacrificing a part of themselves: This can range from decoy burial chambers designed to mislead grave robbers, a fuse deliberately melting within an electrical circuit to protect other appliances, or a lizard’s tail detaching to facilitate its escape.
This concept of sacrificial elements can also be observed in collagen, the most abundant protein in our bodies. Researchers at the Heidelberg Institute for Theoretical Studies (HITS) have revealed how the rupture of weak sacrificial bonds within collagen tissue helps to localize damage caused by excessive force, minimize negative impacts on the wider tissue, and promote recovery.
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Collagen comprises roughly 30 percent of all proteins in the human body. It provides strength to bones, elasticity to skin, protection to organs, flexibility to tendons, aids in blood clotting, and supports the growth of new cells. Structurally, collagen resembles a triple-braided helix: Three chains of
Mature crosslinks in collagen consist of two arms: one of which is weaker than other bonds in collagen tissue. When subjected to excessive force, the weaker arm is typically first to rupture, dissipating the force and localizing detrimental effects. The scientists found that in regions of collagen tissue where weak bonds are present, other bonds – both in the crosslinks and the collagen backbone – are more likely to remain intact, thereby preserving the structural integrity of the collagen tissue.
Previous work led by HITS scientists revealed that excessive mechanical stress on collagen leads to the generation of radicals, which in turn cause damage and oxidative stress in the body.
“Our latest research shows that sacrificial bonds in collagen serve a vital role in maintaining the overall integrity of the material can help to localize the impacts of this mechanical stress that could otherwise have catastrophic consequences for the tissue,” explains Benedikt Rennekamp, the study’s first author. “As collagen is a major substituent of tissues in our bodies, by uncovering and understanding these rupture sites, researchers can gain valuable insights into the mechanics of collagen and potentially develop strategies to enhance its resilience and mitigate damage.”
Reference: “Collagen breaks at weak sacrificial bonds taming its mechanoradicals” by Benedikt Rennekamp, Christoph Karfusehr, Markus Kurth, Aysecan Ünal, Debora Monego, Kai Riedmiller, Ganna Gryn’ova, David M. Hudson and Frauke Gräter, 12 April 2023, Nature Communications.
DOI: 10.1038/s41467-023-37726-z
The study was funded by the H2020 European Research Council and Klaus Tschira Stiftung.