Microspectroscopic evidence of cretaceous bone proteins

• Published in: PloS one Vol. 6; no. 4; p. e19445
• Main Authors: Lindgren, Johan, Uvdal, Per, Engdahl, Anders, Lee, Andrew H, Alwmark, Carl, Bergquist, Karl-Erik, Nilsson, Einar, Ekström, Peter, Rasmussen, Magnus, Douglas, Desirée A, Polcyn, Michael J, Jacobs, Louis L
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 29.04.2011; Public Library of Science (PLoS)
• Subjects: Acids; Alcohol; Amino acid composition; Amino acids; Analysis; Aniline Compounds - pharmacology; Animals; Antibodies; Bacteria; Biofilms; Biology; Biomedical materials; Biomolecules; Bone and Bones - chemistry; Bone and Bones - metabolism; Bone composition; Bone mass; Bone matrix; Bone Matrix - chemistry; Bones; Cameras; Clinical Medicine; Collagen; Collagen (type I); Collagen - chemistry; Contaminants; Cretaceous; Cretaceous period; Demineralizing; Earth science; Earth Sciences; Ecosystem biology; Ecosystems; Fibrils; Fossils; Humerus; Humerus - pathology; I.R. radiation; Immunofluorescence; Infectious diseases; Infectious Medicine; Infektionsmedicin; Klinisk medicin; Low concentrations; Marine sediments; Mass spectrometry; Mass Spectrometry - methods; Medical and Health Sciences; Medicin och hälsovetenskap; Microscopy; Microscopy, Confocal - methods; Microscopy, Electron, Scanning - methods; Microscopy, Electron, Transmission - methods; Microscopy, Fluorescence - methods; Organic chemistry; Oxidation; Paleontology - methods; Particle accelerators; Periodic variations; Periodicity; Polyesters; Preservation; Proteins; Radiation; Sandstone; Scientific imaging; Sediments; Soft tissues; Spectrometry; Spectrophotometry - methods; Spectrophotometry, Infrared - methods; Structural proteins; Synchrotron radiation; Tissues; United States > US; Sweden; Texas
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0019445

Low concentrations of the structural protein collagen have recently been reported in dinosaur fossils based primarily on mass spectrometric analyses of whole bone extracts. However, direct spectroscopic characterization of isolated fibrous bone tissues, a crucial test of hypotheses of biomolecular preservation over deep time, has not been performed. Here, we demonstrate that endogenous proteinaceous molecules are retained in a humerus from a Late Cretaceous mosasaur (an extinct giant marine lizard). In situ immunofluorescence of demineralized bone extracts shows reactivity to antibodies raised against type I collagen, and amino acid analyses of soluble proteins extracted from the bone exhibit a composition indicative of structural proteins or their breakdown products. These data are corroborated by synchrotron radiation-based infrared microspectroscopic studies demonstrating that amino acid containing matter is located in bone matrix fibrils that express imprints of the characteristic 67 nm D-periodicity typical of collagen. Moreover, the fibrils differ significantly in spectral signature from those of potential modern bacterial contaminants, such as biofilms and collagen-like proteins. Thus, the preservation of primary soft tissues and biomolecules is not limited to large-sized bones buried in fluvial sandstone environments, but also occurs in relatively small-sized skeletal elements deposited in marine sediments.