Figure 5 in Mechanisms of soft tissue and protein preservation in Tyrannosaurus rex

Figure 5. SR-FTIR analysis of T. rex vascular tissue, NaBH4 reduced T. rex vascular tissue, chicken type I collagen without treatment, and chicken type I collagen treated with Fenton reagent and iron-catalysed glycation. (a,b) Average FTIR spectra in the non-peptide carbonyl and protein amide I regions for all five samples. (a) Significant reduction in the non-peptide carbonyl band follows treatment of T. rex vascular tissue with NaBH4, which reduces (immature) peptide crosslinks. The blue-shifted Amide I band of the dinosaur tissue, Fenton reagent-treated chicken type I collagen, and Fe-catalysed glycation-treated chicken type I collagen indicate increasing α-helix structure (~1660 cm−1) as the higher-energy triple-helix and intermolecular sub-bands (see Fig. 1 for method of identification) increasingly predominate the spectra. The development of aldehydic carbonyl, ketoaldehyde, and/or immature ketoimine bands in both treated chicken tissues is consistent with the strong carbonyl band in the dinosaur tissue.