Como proteínas em fósseis de dinossauros foram protegidas por milhões de anos

quarta-feira, junho 15, 2011

Published online 14 June 2011 | Nature | doi:10.1038/news.2011.369


Twisted structure preserved dinosaur proteins

Collagen coils might have kept Tyrannosaurus molecules safe from harm for millions of years.

Ed Yong

Researchers are divided on whetherTyrannosaurus rex proteins have survived to the present day.
L. Psihoyos/Corbis

Scientists have discovered how fragments of the protein collagen might have survived in fossilized dinosaur bones. The intertwining, rope-like structure of the molecule, a major component of bone, could have shielded parts of the protein from enzymes and the elements for tens of millions of years, they say.
The results, which are published in PLoS ONE1, support the contentious claim that dinosaur proteins have been recovered and sequenced.

Collagen molecules consist of three long protein subunits that coil around each other in a triple helix. Five of these helices wind together to make up a microfibril, and thousands of microfibrils gather to form a fibril.

"It's like a massive, multi-stranded rope," says James San Antonio, lead author of the paper and a biochemist at Orthovita, a medical-implant manufacturer in Malvern, Philadelphia.

San Antonio and his colleagues analysed 11 fragments of collagen recovered from the fossilized bones of a 68-million-year-oldTyrannosaurus rex and an 80-million-year-old Brachylophosaurus canadensis.

Mary Schweitzer, a palaeontologist at North Carolina State University in Raleigh, and her colleagues have previously claimed to have found soft tissues and collagen in these remains2,3. Other scientists think that the recovered proteins are modern contaminants (see 'Origin of T. rex protein questioned')

Read more here/Leia mais aqui: Nature


Dinosaur Peptides Suggest Mechanisms of Protein Survival

James D. San Antonio1*, Mary H. Schweitzer2,3,4, Shane T. Jensen5, Raghu Kalluri6,7, Michael Buckley8,9, Joseph P. R. O. Orgel10*

1 Operations, Orthovita, Inc., Malvern, Pennsylvania, United States of America, 2 Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina, United States of America, 3 North Carolina Museum of Natural Sciences, Raleigh, North Carolina, United States of America, 4 Museum of the Rockies, Montana State University, Bozeman, Montana, United States of America, 5 Department of Statistics, The Wharton School, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America, 6 Division of Matrix Biology, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, United States of America, 7 Department of Biological Chemistry and Molecular Pharmacology, Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology, Boston, Massachusetts, United States of America, 8 Manchester Interdisciplinary Biocentre, Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom, 9 Department of Archaeology, The University of York, York, United Kingdom, 10 Department of Biology, Pritzker Institute of Biomedical Science and Engineering, Illinois Institute of Technology, Chicago, Illinois, United States of America


Eleven collagen peptide sequences recovered from chemical extracts of dinosaur bones were mapped onto molecular models of the vertebrate collagen fibril derived from extant taxa. The dinosaur peptides localized to fibril regions protected by the close packing of collagen molecules, and contained few acidic amino acids. Four peptides mapped to collagen regions crucial for cell-collagen interactions and tissue development. Dinosaur peptides were not represented in more exposed parts of the collagen fibril or regions mediating intermolecular cross-linking. Thus functionally significant regions of collagen fibrils that are physically shielded within the fibril may be preferentially preserved in fossils. These results show empirically that structure-function relationships at the molecular level could contribute to selective preservation in fossilized vertebrate remains across geological time, suggest a ‘preservation motif’, and bolster current concepts linking collagen structure to biological function. This non-random distribution supports the hypothesis that the peptides are produced by the extinct organisms and suggests a chemical mechanism for survival.

Citation: San Antonio JD, Schweitzer MH, Jensen ST, Kalluri R, Buckley M, et al. (2011) Dinosaur Peptides Suggest Mechanisms of Protein Survival. PLoS ONE 6(6): e20381. doi:10.1371/journal.pone.0020381

Editor: Hendrik W. van Veen, University of Cambridge, United Kingdom

Received: February 2, 2011; Accepted: May 1, 2011; Published: June 8, 2011

Copyright: © 2011 San Antonio et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funding: This research was funded by NIH RR 08630 and an NSF Career Award 0644015 to JPROO; NIH DK 55001 grant to RK; and grants from NSF and The David and Lucile Packard Foundation to MHS. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The lead author is an employee of private industry, Orthovita, Inc. However, this is an academic study that the company is allowing to be researched and published, and with which they have no financial or proprietary interest. The last author, J. Orgel, is a Biochemistry Section Editor of PLOS ONE. This does not alter the authors' adherence to all the PLOS ONE policies on sharing data and materials.

* E-mail: (JDSA); (JPROO)