A remarkable study was published describing the use of mass spectrometry to sequence proteins from 68 million year old fossilized bones of Tyrannosaurus rex (Asara et al, 2007).

This study identified collagen sequences from the bones and showed that the peptide sequences were rich in post-translational modifications such as hydroxproline and hydroxylysine that stabilize collagen fibrillar structures.

There was considerable controversy surrounding this study, primarily focused on the data analysis methods used. Other studies have re-analyzed the primary mass spectrometry data and drawn their own conclusions.


Re-analyze the data and attempt to identify the collagen peptides at the heart of this fascinating story.


Parameter settings


These are the selected MS/MS spectra provided by the authors

Specify variable oxidation of proline, lysine, methionine as described in the Methods. Select 'DTA' as file format. Check 'Display all modifications' to see oxidation of proline