Meaghan Mackie

Using Palaeoproteomics to Understand the Conservation History of a Painting

Meaghan Mackie §; Patrick Rüther £; Diana Samodova £; Fabiana Di Gianvincenzo §; Clara Granzotto §; David Lyon £; David A. Peggie #; Helen Howard #; Lynne Harrison #; Lars Juhl Jensen £; Jesper V. Olsen £; Enrico Cappellini §

£ Novo Nordisk Center for Protein Research, University of Copenhagen; §Natural History Museum of Denmark, University of Copenhagen; # National Gallery of London

Protein-based materials have been used extensively in cultural heritage objects, not just in the original creation of the object, but also during later conservation. Their identification can provide insight into artistic technique or history of the object and can be helpful in defining display and storage conditions, as well as conservation protocols. Current technologies often found in galleries and museums, such as Fourier transform infrared spectroscopy (FTIR), can help identify presence of proteins in these objects, but often cannot distinguish between different proteins or their biological source (species). Therefore, mass spectrometry and paleoproteomics can provide insight into these cultural heritage objects by identifying proteins and their sources, with the added ability to also identify the post-translational modifications (PTMs) that have occurred. As an example, we present recent work done to understand the conservation history of a 14th century Italian wall painting. Two layers were determined: sheep and cow glue and chicken and duck egg white. Analysis of PTMs detected several photo-oxidation products, which suggest that the egg layer experienced prolonged exposure to UV light, meaning it was likely applied long before the glue layer. We demonstrate that paleoproteomics can provide important information for understanding the history and function of materials identified in cultural heritage objects and for informing proposed conservation treatments.