Science via AP
These undated photos provided by the journal Science show demineralized fragments of tissues lining the marrow cavity of a Tyrannosaurus rex femur. The find included what appear to be blood vessels, and possibly even cells.
Scientists have discovered how bits of the protein collagen from dinosaurs that died millions of years ago might have survived in fossilized bones.
The new research shows the rope-like connective tissue is twisted in such a way that certain parts are shielded from biological degradation and could survive for millions of years.
James San Antonio, a biochemist at Orthovita, a medical-implant manufacturer, and colleagues looked at bits of collagen extracted from dinosaur bones and compared them to where those bits show up in collagen fibers of rats and humans.
They found that all 11 pieces analyzed came from the innermost parts of the fibers where they would have been protected from degradation by enzymes and the elements.
What's more, several of the molecules contain amino acids that are water-hating and contain few acidic amino acids, which make them less vulnerable to degradation by enzymes and water.
"We were rather pleasantly surprised and taken aback," Orgel told ScienceNews, adding that if any molecules were to survive millions of years, it would be the sheltered kinds they observed.
Those studies are controversial since many scientists believe there's no way soft tissue could survive millions of years and thus what has been found and sequenced is actually contamination from more recent times.
The new finding, reported in PLoS One, has yet to convince the skeptics.
"I'm an old protein cynic," Matthew Collins of the University of York in England, told ScienceNews. "Obviously, we would like to see a lot of samples from lots of labs. I'm not convinced yet."
The study was based on data from the initial reports. And that data, geneticist Stephen Salzberg at the University of Maryland has pointed out in a comment at PLoS One "are contaminants from modern species," notes Nature News.
The new study's authors refute the criticism, saying that if the fibers were contaminants, they should be from random parts of the structure. All the bits they found were from the most protected regions.
So, the controversy remains, but the new study does show how these proteins could survive millions of years. And if they did, scientists believe they'll be able to gain insight on how dinosaurs lived.
More on dinosaur proteins:
- T. rex analysis supports dino-bird link
- Proteins could reveal new dinosaur secrets
- Gunk in T. rex fossil confirms dino-bird lineage
- Scientists recover T. rex soft tissue
- Dinosaur mummy reveals organic molecules
John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).