Palaeoproteomics of archaeological shell beads

In this project we have applied palaeoproteomics to study archaeological shell beads dating back to the beginning of the 7th mill. cal BCE and recovered from a prehistoric site in Jordan (Ba'ja). These beads were made of mollusc shells and were of unknown origin, but suspected to be made of larger bivalves such as Tridacna or Spondylus sp. The aim of the study was to analyse ancient proteins extracted from these beads in order to infer their biological origin. Tiny amounts of ancient samples were used and the extracted proteins were analysed by high resolution liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). In order to identify obtained peptides, we have created an ‘in-house’ molluscan protein database, by gathering molluscan sequences (proteins and transcriptomes), which were downloaded from publicly available databases in NCBI. Searching against this comprehensive database, we were able to identify a number of shell proteins from Tridacna sp., the giant clam shells. Our study reports the oldest molluscan protein sequences ever recovered that come from a very warm environment.