Quantitative metaproteomics of medieval dental calculus reveals individual oral health status

The composition of the ancient oral microbiome has recently become possible to investigate by using advanced biomolecular methods such as metagenomics and metaproteomics. This study presents a look at the individuality of the metaproteomes from 22 medieval Danish dental calculus samples. The proteomics data suggest two distinct groups; a healthy and disease-susceptible. Comparison to modern healthy calculus samples supports this hypothesis. The osteological inspections of the samples does not immediately support the grouping made by proteomics data, making us believe that this will add a new and exciting level of information. We identify 3671 protein-groups across all medieval samples and thus expanding the depth of previous studies more than ten times. As a part of future perspective for further depth in these types of samples we performed offline high pH fractionation in combination with TMT labelling and achieved ~30% more protein identifications and reduced costly mass spectrometry time.