Resonance Raman measurements on fossilized remains show ancient heme-globin complex

Still-soft, hollow, and flexible structures morphologically consistent with blood vessels recovered from demineralized dinosaur bone were studied with resonance Raman techniques to test the hypothesis that these vessel-like structures are original to the dinosaur, and that they maintain endogenous molecular characteristics. Modern, artificially aged analogs show the beginnings of similar processes. We probed these samples using resonance Raman at two different wavelengths. Doubly selective resonant Raman techniques confirms the co-location of a heme moiety onto a larger globin protein by probing both heme vibrational modes and a excitation-resonant bond simultaneously. The existence of a stronger resonance Raman signal level in the green compared to blue excitation is consistent with a hemoglobin, not just heme, absorption resonance. These data imply that heme moieties in the soft structures are attached to remnant globins, or fragments thereof. Further, analysis of the Raman spectra of these hemoglobin remnants show damage to the outer regions of the heme ring, indicative of diagenetic change consistent with an ancient endogenous source. Separately, the formation of goethite crystallites still attached to the hemoglobin remnant suggest a possible mechanism for preservation.