Paleoproteomic profiling of organic residues on prehistoric pottery from Malta

Abstract

Mass spectrometry-based approaches have been successfully applied for identifying ancient proteins in bones and other tissues. On the contrary, there are relatively few examples of the successful recovery and identification of archeological protein residues from ceramic artifacts; this is because ceramics contain much lower levels of proteins which are extensively degraded by diagenetic effects. In this paper, we report the results of the characterization of proteins extracted from pottery of the Maltese site of Baħrija, the guide-site for the Baħrija period (half of 9th-second half of eighth century BCE), recently identified as the final part of the Borġ in-Nadur culture. Proteomic data here reported confirm that one of the major issue of these kind of studies is represented by contamination of animal and human agents that may complicate endogenous protein identification and authentication. The samples tested included a small group of ceramic forms, namely three tableware and six coarse ware thought to have been used in food preparation and/or storage. In this context, the limited availability of paleobotanical and archeozoological analyses may be compensated by the outcomes of the first proteomics profiling which, even if obtained on a limited selection of vessels, revealed the centrality of wheat in the diet of the ancient community of Baħrija. The data have been deposited to the ProteomeXchange with identifier < PXD022848 > .

Keywords: Cereal proteins; Deamidation; High-resolution mass spectrometry; Orbitrap fusion tribrid; Paleoproteomics.

Fig. 1

Contour Map of il-Qlejgħa tal-Baħrija area, NW Malta (after Cardona and Zammit 2015)

Fig. 2

General site plan of il-Qlejgħa tal-Baħrija showing all the known archeological features (Cardona and Zammit 2015)

Fig. 3

Deamidation level (reported as percentage) of asparagine (N) and glutamine (Q) amino acids in the archeological samples analyzed