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Mass spectrometry-based methods for identifying oxidized proteins in disease: advances and challenges.

Verrastro I, Pasha S, Jensen KT, Pitt AR, Spickett CM - Biomolecules (2015)

Bottom Line: It is now increasingly recognized that oxidative post-translational modifications (oxPTMs) of proteins affect cell signalling and behaviour, and can contribute to pathology.Nevertheless, many potential pitfalls exist which can result in incorrect identifications.This review explains the limitations, advantages and challenges of all of these approaches to detecting oxidatively modified proteins, and provides an update on recent literature in which they have been used to detect and quantify protein oxidation in disease.

View Article: PubMed Central - PubMed

Affiliation: School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK. verrasti@aston.ac.uk.

ABSTRACT
Many inflammatory diseases have an oxidative aetiology, which leads to oxidative damage to biomolecules, including proteins. It is now increasingly recognized that oxidative post-translational modifications (oxPTMs) of proteins affect cell signalling and behaviour, and can contribute to pathology. Moreover, oxidized proteins have potential as biomarkers for inflammatory diseases. Although many assays for generic protein oxidation and breakdown products of protein oxidation are available, only advanced tandem mass spectrometry approaches have the power to localize specific oxPTMs in identified proteins. While much work has been carried out using untargeted or discovery mass spectrometry approaches, identification of oxPTMs in disease has benefitted from the development of sophisticated targeted or semi-targeted scanning routines, combined with chemical labeling and enrichment approaches. Nevertheless, many potential pitfalls exist which can result in incorrect identifications. This review explains the limitations, advantages and challenges of all of these approaches to detecting oxidatively modified proteins, and provides an update on recent literature in which they have been used to detect and quantify protein oxidation in disease.

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Structures of oxidized residues most commonly detected and studied by mass spectrometry. In mixed disulfides, R can be cysteine or glutathione (glutathionylation).
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biomolecules-05-00378-f001: Structures of oxidized residues most commonly detected and studied by mass spectrometry. In mixed disulfides, R can be cysteine or glutathione (glutathionylation).

Mentions: Many diseases have an oxidative aetiology resulting from activation of the immune system, mitochondrial dysfunction or environmentally-induced oxidative stress. Oxidative modification of proteins can have multiple effects, such as loss of enzymatic activity, functional alterations, loss of structural integrity, and protein aggregation [1]. Various different reactive and oxidizing species exist and vary in their reactivity to protein residues and sites. Metal-catalysed oxidation depends on the formation of hydroxyl radicals through Fenton chemistry; hydroxyl radicals are highly reactive and able to modify almost any site through hydrogen abstraction and peroxide formation, often leading to backbone fragmentation. The most susceptible side chains in proteins are the sulfur-containing cysteine and methionine side chains; the reactivity of cysteine with hydrogen peroxide depends on the pKa of the thiol group as the thiolate anion is a better nucleophile. Cysteine can also react with reactive nitrogen species to form nitrosothiols (Figure 1). Other residues that are commonly oxidized include histidine, proline, lysine and arginine, where hydroxylation or formation of aldehydes or ketones may occur. Reactive nitrogen compounds derived from peroxynitrite are often both nitrating and oxidizing. Sites susceptible to nitration include tyrosine (forming 3-nitrotyrosine) and tryptophan. Hypohalites can also react with aromatic residues to form halogenated products such as 3-chloro and 3-bromotyrosine [2].


Mass spectrometry-based methods for identifying oxidized proteins in disease: advances and challenges.

Verrastro I, Pasha S, Jensen KT, Pitt AR, Spickett CM - Biomolecules (2015)

Structures of oxidized residues most commonly detected and studied by mass spectrometry. In mixed disulfides, R can be cysteine or glutathione (glutathionylation).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4496678&req=5

biomolecules-05-00378-f001: Structures of oxidized residues most commonly detected and studied by mass spectrometry. In mixed disulfides, R can be cysteine or glutathione (glutathionylation).
Mentions: Many diseases have an oxidative aetiology resulting from activation of the immune system, mitochondrial dysfunction or environmentally-induced oxidative stress. Oxidative modification of proteins can have multiple effects, such as loss of enzymatic activity, functional alterations, loss of structural integrity, and protein aggregation [1]. Various different reactive and oxidizing species exist and vary in their reactivity to protein residues and sites. Metal-catalysed oxidation depends on the formation of hydroxyl radicals through Fenton chemistry; hydroxyl radicals are highly reactive and able to modify almost any site through hydrogen abstraction and peroxide formation, often leading to backbone fragmentation. The most susceptible side chains in proteins are the sulfur-containing cysteine and methionine side chains; the reactivity of cysteine with hydrogen peroxide depends on the pKa of the thiol group as the thiolate anion is a better nucleophile. Cysteine can also react with reactive nitrogen species to form nitrosothiols (Figure 1). Other residues that are commonly oxidized include histidine, proline, lysine and arginine, where hydroxylation or formation of aldehydes or ketones may occur. Reactive nitrogen compounds derived from peroxynitrite are often both nitrating and oxidizing. Sites susceptible to nitration include tyrosine (forming 3-nitrotyrosine) and tryptophan. Hypohalites can also react with aromatic residues to form halogenated products such as 3-chloro and 3-bromotyrosine [2].

Bottom Line: It is now increasingly recognized that oxidative post-translational modifications (oxPTMs) of proteins affect cell signalling and behaviour, and can contribute to pathology.Nevertheless, many potential pitfalls exist which can result in incorrect identifications.This review explains the limitations, advantages and challenges of all of these approaches to detecting oxidatively modified proteins, and provides an update on recent literature in which they have been used to detect and quantify protein oxidation in disease.

View Article: PubMed Central - PubMed

Affiliation: School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK. verrasti@aston.ac.uk.

ABSTRACT
Many inflammatory diseases have an oxidative aetiology, which leads to oxidative damage to biomolecules, including proteins. It is now increasingly recognized that oxidative post-translational modifications (oxPTMs) of proteins affect cell signalling and behaviour, and can contribute to pathology. Moreover, oxidized proteins have potential as biomarkers for inflammatory diseases. Although many assays for generic protein oxidation and breakdown products of protein oxidation are available, only advanced tandem mass spectrometry approaches have the power to localize specific oxPTMs in identified proteins. While much work has been carried out using untargeted or discovery mass spectrometry approaches, identification of oxPTMs in disease has benefitted from the development of sophisticated targeted or semi-targeted scanning routines, combined with chemical labeling and enrichment approaches. Nevertheless, many potential pitfalls exist which can result in incorrect identifications. This review explains the limitations, advantages and challenges of all of these approaches to detecting oxidatively modified proteins, and provides an update on recent literature in which they have been used to detect and quantify protein oxidation in disease.

Show MeSH
Related in: MedlinePlus