First ancient proteome revealed

Mammoth femur yields 126 prehistoric proteins.

The groups of Lars J. Jensen and Jesper V. Olsen from Novo Nordisk Foundation Center for Protein Research at the University of Copenhagen together with scientists at the Center for GeoGenetics at the Natural History Museum of Denmark and international co-workers used high-sensitivity, high-resolution tandem mass spectrometry to sequence proteins extracted from a 43,000 year old woolly mammoth bone that had been preserved in Siberian permafrost. 

For the first time, 126 unique protein accessions, mostly low-abundance extracellular matrix and plasma proteins, were confidently identified by solid molecular evidence. Among the best characterized was the carrier protein serum albumin, presenting two single amino acid substitutions compared to extant African (Loxodonta africana) and Indian (Elephas maximus) elephants. Strong evidence was observed of amino acid modifications due to post-mortem hydrolytic and oxidative damage. A consistent subset of this permafrost bone proteome was also identified in more recent Columbian mammoth (Mammuthus columbi) samples from temperate latitudes, extending the potential of the approach described beyond subpolar environments. Mass spectrometry-based ancient protein sequencing offers new perspectives for future molecular phylogenetic inference and physiological studies on samples not amenable to ancient DNA investigation. This approach therefore represents a further step into the ongoing integration of different high-throughput technologies for identification of ancient biomolecules, unleashing the field of paleoproteomics.