Peptide bond interactions explain collagen’s ‘impossible’ longevity in dinosaur bones

Interactions between neighbouring peptide bonds could explain how the collagen in dinosaur bones remains intact for hundreds of millions of years.

Bone collagen is commonly used for palaeobiological dating because of its deep roots in the animal kingdom – fragments of type-I collagen have been extracted from the bones of 68- and 80-million-year-old fossils of Tyrannosaurus rex and Brachylophosaurus canadensis, respectively. The longevity of peptide bonds in collagen is something of a chemical mystery though, as their half-life in a neutral aqueous solution is just 500 years, meaning they can persist for more than a million times longer than expected. A team based at the Massachusetts Institute of Technology (MIT) were intrigued by this longstanding puzzle and set out to find a chemical explanation for this surprising longevity.