PROTEIN AND POST-TRANSLATIONAL MODIFICATION PRESERVATION IN CASTOROIDES OHIOENSIS FROM NEW YORK

Preserved protein in fossilized bone has become a direct means for obtaining molecular information from samples that are beyond the age limit of DNA preservation, as well as understanding post-translational modifications (i.e., protein modifications that are not coded from DNA but added by enzymes after translation). Evidence exists to support that molecular preservation declines in bone after excavation and storage in museums, yet few studies have examined the preservation of proteins in historically collected specimens. Here, we examine the preservation of proteins in the first skull of Castoroides ohioensis (NYSM VP-47; 10,150 ± 50 ¹⁴C BP), which was collected in 1845. NYSM VP-47 was collected from a fine sand layer below a layer of peat, a typical depositional environment for fossils of this age in New York. We were able to detect extensive collagen I sequences and a short peptide of hemoglobin from the nasal turbinates of this skull using a ThermoScientific Orbitrap XL mass spectrometer after separation on an Agilent 1200 series HPLC. The collagen I sequences allowed for molecular placement of C. ohioensis in Rodentia for the first time, consistent with morphological analysis of this species. We were also able to detect the post-translational modifications from the collagen I derived from the Castoroides ohioensis as well as from diagenetic changes to the proteins. This study represents the first use of mass spectrometry on Pleistocene taxa from the northeastern United States, and the first characterization of collagen I sequences from Castoroides ohioensis.