Georgia Ntasi (UNINA)

Objectives

The ESR5 will focus on the analysis and definition of ancient protein deamidation with the use of mass spectrometry (MS) using ancient human bones from excavation sites Herculaneum and Pompeii as a case study and then expanding this knowledge for the study of protein degradation in other archaeological remains and works of art.

Expected results

The projects aims to facilitate new and deeper strategic research, in the characterization of a wider range of modifications, those expected as well as those not yet characterized, that occur in proteins upon aging of deterioration in samples that have been exposed to a wide spectrum of different environmental conditions.

My project

A challenging, as well as intriguing peculiarity of ancient proteins is their signature pattern of deterioration and aging represented by covalent modifications. Distinction between modifications occurred in vivo and diagenetically derived alterations will provide important information on the physiology of ancient organisms, and on the aging and deterioration of artworks. Rigorous identification of protein degradation products and the reconstruction of their formation pathways, through spontaneous reactions with endogenous or exogenous compounds, will also be associated with specific environmental factors, leading to develop a more efficient preservation of ancient samples. Much work still needs to be done to understand and characterize the whole range of modifications occurring during proteins aging in samples exposed to a wide spectrum of different environmental conditions. In this thematic section, characterisation of modifications known to accumulate in ancient samples over millennia, such as deamidation and oxidation, as well as blind search for other, less common, spontaneous modifications will be used to identify environmental changes, aging and diagenetic factors.

It is still an open question whether deamidation of glutamine (Q) and asparagine (N) could be used as a dating technique in ancient samples, but it is widely accepted that deamidation can be considered as a biomolecular marker of deterioration and natural aging of proteins in artistic and archaeological materials . Detection of deamidation can offer interesting prospects in the evaluation of the conservation state of work of arts and archaeological remains. However, deamidation is a delicate modification, since it is strongly influenced by several parameters such as pH and temperature. Deamidation is also a delicate modification from a purely technical point of view, since it induces a mass shift of only 0.98 Da, and deamidation can occur also as a by-product of sample preparation. This modification will be explored as specific signature of the conservation state of collagens from bones from Herculaneum and Pompeii (that although arising from the same catastrophic event have experienced different burial conditions). The work will beneficiate of the interaction with the anthropologist Dr. Pierpaolo Petrone (University of Naples, Federico II) and the professional restorer (Dr. Giancarlo Fatigati) collaborating with the Museo Archeologico di Napoli (MAN), to widen the technical approaches to samples. Methodological development will allow proper quantification of deamidation levels and identification of unexpected modifications that can be used as molecular signatures of deterioration/aging.

Networking

Planned secondments:

1. Secondment period of 3-4 months at USTL (co-supervision), to compare analytical procedures.

2. Secondment period of 4-5 months at UoY to share and compare experience on ancient protein degradation with Gopaiah Talari and Matthew Collins.