( 25) used a redox proteomics approach to identify specifically carbonylated proteins in the inferior parietal lobule from human subjects with mild cognitive impairment and early stage Alzheimer's disease, providing insights to the mechanism of the progression of this disease. This redox proteomics approach allowed for the identification of carbonylated proteins in various diseases in humans, animals models, and cell models, and has provided important information to biologists by describing the effects of modifications by carbonyl species on protein function, as well as the consequences of such modifications at the cellular level.īutterfield and co-workers developed this proteomics approach to identify specifically oxidized proteins in Alzheimer's disease by detecting carbonylated proteins ( 7, 10, 12). More recently, these methods contributed to a rapid progress in proteomic analyses of carbonylated proteins using two-dimensional gel electrophoresis, followed by immunoblotting and mass spectrometry. The development of the antibody against DNPH-derivatized proteins revolutionalized the studies of carbonylated proteins by allowing for the use of immunological techniques ( 16, 17, 22). Although the biology of oxidative protein modifications is complex and remains incompletely defined, protein carbonylation and chemistry of the reactions that give rise to carbonyl groups have been well characterized ( 24). Oxidative decomposition of polyunsaturated fatty acids initiates chain reactions that lead to the formation of a variety of carbonyl species (three to nine carbons in length), the most reactive and cytotoxic being α,β-unsaturated aldehydes (4-hydroxy- trans-2-nonenal and acrolein), di-aldehydes (malondialdehyde and glyoxal), and keto-aldehydes (4-oxo- trans-2-nonenal). DNPH derivatizable protein products can also be formed in the “secondary protein carbonylation” reaction via the addition of aldehydes such as those generated from lipid peroxidation processes ( 14, 21). Direct oxidation of side chains of lysine, arginine, proline, and threonine residues, among other amino acids, in the “primary protein carbonylation” reaction produces DNPH detectable protein products ( 11, 15, 23). It usually refers to a process that forms reactive ketones or aldehydes that can be reacted by 2,4-dinitrophenylhydrazine (DNPH) to form hydrazones. Finally, these results allowed to reinforce the hypothesis of oxidative damage in erythrocyte membrane proteins as molecular mechanism of human adaptation to malaria infection.P rotein carbonylation is a type of protein oxidation that can be promoted by reactive oxygen species. Therefore, both polymorphisms promote carbonylation on the same membrane proteins. Erythrocytes with G6PD deficient and SCT showed higher carbonyl index values than control and similar profiles of carbonylated proteins moreover, cytoskeletal and stress response proteins were identified as the main targets of oxidative damage. Besides, protein carbonylation profiles were obtained by Western blot and complemented with mass spectrometry using MALDI-TOF-TOF analysis. Carbonyl index by dot blot assay was used to calculate the variation of oxidative damage during the asexual phases. falciparum 3D7 were used to quantify oxidative damage in membrane proteins of erythrocytes with G6PD deficient and SCT. Here, synchronous cultures at high parasitemia levels of P. Nevertheless, mechanisms are not completely understood at molecular level for each polymorphism yet, and even less if are commons for several of them. There exist in both a prooxidant environment that favors the oxidative damage on membrane proteins, which probably is part of molecular protector mechanisms. Both are considered the result of the selective pressure exerted by Plasmodium parasites over human genome, due to a certain degree of resistance to the clinical symptoms of severe malaria.
Deficiency of glucose-6-phosphate dehydrogenase (G6PD) and sickle cell trait (SCT) are described as the polymorphic disorders prevalent in erythrocytes.
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