Deamidation at Asparagine and Glutamine As a Major Modification upon Deterioration/Aging of Proteinaceous Binders in Mural Paintings

Leo, G.; Bonaduce, Ilaria; Andreotti, Alessia; Marino, Gennaro; Pucci, Piero; Colombini, Maria Perla; Birolo, Leila

doi:10.1021/ac1027275

Cited by 92 publications

(89 citation statements)

References 25 publications

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“…No fixed chemical modification was inserted, but possible oxidation of methionine residues, formation of pyroglutamic acid from glutamine residues at the Nterminal position of peptides, and deamidation at asparagines and glutamines were considered as variable modifications. 6 When collagen proteins were identified, a further identification run was carried out, with the insertion of hydroxylation on Lysine and Proline as variable modifications, since more confident identifications are commonly obtained for these proteins by taking into consideration their extensive post-translational modifications. 4 Only proteins presenting two or more peptides were considered as positively identified.…”

Section: Methodsmentioning

confidence: 99%

Deglycosylation Step to Improve the Identification of Egg Proteins in Art Samples

et al. 2015

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A deglycosylation step using Peptide-N-Glycosidase F (PNGaseF) has been introduced in a standard proteomic protocol to more confidently identify egg based binders. The ingenuity of introducing a PNGaseF digestion was aimed at removing the molecular hindrance, made up by the heavily glycosylated egg proteins, before the protease(s) hydrolysis. This novelty in the protocol resulted in obtaining a significant increase of proteolytic egg peptides thus improving the quality and reliability of egg identification in artwork samples. The protocol has been set up on paint replicas and successfully tested on two historical samples of different origin.

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Section: Methodsmentioning

confidence: 99%

Deglycosylation Step to Improve the Identification of Egg Proteins in Art Samples

et al. 2015

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“…1–3 Such deamidation is also observed in vitro upon the aging of proteinaceous material, for example, woolen textiles, 4 works of art, 5 and foodstuffs. 6 However, not all Asn and Gln residues are deamidated equally readily.…”

mentioning

confidence: 93%

Deamidation of Human γS-Crystallin Increases Attractive Protein Interactions: Implications for Cataract

2015

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Deamidation of proteins is one of the most prevalent post-translational modifications found upon aging, and in age-onset diseases. Specific asparagine and glutamine residues are often selectively deamidated during this process. In the human lens, deamidation has been shown to occur in many crystallins, but it is not clear how these deamidated proteins lead to lens opacity or cataract. Here we have modeled in vitro the effect of deamidation of specific asparagine and glutamine residues in human recombinant γS-crystallin (HGS) on the solution properties of the protein. The residues selected for deamidation in vitro are those that are found to be deamidated in aged and cataractous lenses in vivo. Two derivatives were prepared, one with Asn76 and Asn143 deamidated (2N-HGS) and the other with two additional Gln residues (92 and 120) deamidated (2N2Q-HGS). Isoelectric focusing measurements showed the expected lowering of the pI from 6.9 in HGS to ~6.5 in 2N-HGS and to ~6.1 in 2N2Q-HGS. However, spectroscopic studies showed no significant change in the secondary and tertiary structures of the deamidated proteins relative to the wild type. The stability of 2N-HGS and 2N2Q-HGS, as measured by guanidinium hydrochloride unfolding, also remained comparable to that of HGS. The main difference was the altered protein–protein interaction among the three proteins. The net repulsive interactions that are characteristic of HGS are diminished in the deamidated derivatives as evidenced by static light scattering measurements of the second virial coefficient, B2 (B2 values for HGS, 2N-HGS, and 2N2Q-HGS of 8.90 × 10−4, 7.10 × 10−4, and 6.65 × 10−4 mL mol g−2, respectively). Further substantiation is provided by estimates of the excess binding energy of protein–protein interactions in the condensed phase, obtained from measurements of the PEG-induced liquid–liquid phase separation profiles for the three proteins. The data suggest that enhanced attractive protein–protein interactions, arising from the deamidation of HGS, promote protein aggregation, thereby leading to increased light scattering and opacity over time.

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“…Proteinaceous material was identified following a minimally invasive proteomic analytical procedure as described in detail the literature [18], except for a preliminary incubation of the sample in strongly protein denaturing conditions (6M Urea) which were introduced in order to favour the exposure of the proteinaceous material to the action of proteases, as also reported in a previous work [19]. …”

Section: Methodsmentioning

confidence: 99%

GC/MS and proteomics to unravel the painting history of the lost Giant Buddhas of Bāmiyān (Afghanistan)

et al. 2017

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A chemical investigation of the organic paint binders of the Giant Buddhas of Bāmiyān was performed using an analytical approach based on mass spectrometry, combining traditional gas chromatography/mass spectrometry protocols with advanced proteomics methodologies. The research was carried out on a selection of rescued fragments. The data revealed the use of egg proteins as the paint binders of the original layers, in accordance with the traditional use of this proteinaceous medium in antiquity, spanning from the Mediterranean basin to the Far East, and already in the Bronze Age. Egg tempera was thus known to artists of the region in the first centuries AD, probably also due to the position of the Bāmiyān valley, which was connected to the Silk Road. Milk was found in the first historical overpaintings. A new proteomics approach was used, which was able to identify the source of the milk proteins present in the restoration layers, despite their age and degradation. In particular cow’s and goat's milk were both found, in agreement with the documented presence of rich pastures in the Bāmiyān valley when the historical restorations were carried out. Investigating the materials of the Giant Buddhas not only enabled us to obtain isolated data on these invaluable works of art, which are now lost, but contributes to understanding the big “puzzle” of our past and the development of our culture, by implementing and supporting written sources, stylistic and anthropological studies with molecular data.

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Deamidation at Asparagine and Glutamine As a Major Modification upon Deterioration/Aging of Proteinaceous Binders in Mural Paintings

Cited by 92 publications

References 25 publications

Deglycosylation Step to Improve the Identification of Egg Proteins in Art Samples

Deglycosylation Step to Improve the Identification of Egg Proteins in Art Samples

Deamidation of Human γS-Crystallin Increases Attractive Protein Interactions: Implications for Cataract

GC/MS and proteomics to unravel the painting history of the lost Giant Buddhas of Bāmiyān (Afghanistan)

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