@article {536, title = {Does reversible cysteine oxidation link the Western diet to cardiac dysfunction?}, journal = {FASEB J}, volume = {28}, year = {2014}, month = {2014 May}, pages = {1975-87}, abstract = {

Using a novel cysteine thiol labeling strategy coupled with mass spectrometric analysis, we identified and quantified the changes in global reversible cysteine oxidation of proteins in the left ventricle of hearts from mice with metabolic syndrome-associated diastolic dysfunction. This phenotype was induced by feeding a high-fat, high-sucrose, type-2 diabetogenic diet to C57BL/6J mice for 8 mo. The extent of reversible thiol oxidation in relationship to the total available (free and reducible) level of each cysteine could be confidently determined for 173 proteins, of which 98 contained cysteines differentially modified >=1.5-fold by the diet. Our findings suggest that the metabolic syndrome leads to potentially deleterious changes in the oxidative modification of metabolically active proteins. These alterations may adversely regulate energy substrate flux through glycolysis, β-oxidation, citric acid (TCA) cycle, and oxidative phosphorylation (oxphos), thereby contributing to maladaptive tissue remodeling that is associated with, and possibly contributing to, diastolic left ventricular dysfunction.

}, keywords = {Animals, Chromatography, Liquid, Citric Acid Cycle, Cysteine, Diet, Fatty Acids, Glycolysis, Heart Diseases, Male, Mice, Mice, Inbred C57BL, Myocardial Contraction, Myocardium, Obesity, Oxidative Phosphorylation, Oxygen, Phenotype, Protein Processing, Post-Translational, Proteomics, Reactive Nitrogen Species, Reactive Oxygen Species, Sulfhydryl Compounds, Tandem Mass Spectrometry}, issn = {1530-6860}, doi = {10.1096/fj.13-233445}, author = {Behring, Jessica B and Kumar, Vikas and Whelan, Stephen A and Chauhan, Pratibha and Siwik, Deborah A and Costello, Catherine E and Colucci, Wilson S and Cohen, Richard A and McComb, Mark E and Bachschmid, Markus M} } @article {537, title = {Redox proteomics of thiol proteins in mouse heart during ischemia/reperfusion using ICAT reagents and mass spectrometry.}, journal = {Free Radic Biol Med}, volume = {58}, year = {2013}, month = {2013 May}, pages = {109-17}, abstract = {

There is strong evidence for the involvement of reactive oxygen species in ischemia/reperfusion injury. Although oxidation of individual thiol proteins has been reported, more extensive redox proteomics of hearts subjected to ischemia/reperfusion has not been performed. We have carried out an exploratory study using mass spectrometry with isotope-coded affinity tags (ICAT) aimed at identifying reversible oxidative changes to protein thiols in Langendorff perfused isolated mouse hearts subjected to 20 min ischemia with or without aerobic reperfusion for 5 or 30 min. Reduced thiols were blocked by adding N-ethylmaleimide during protein extraction, then reversibly oxidized thiols in extracts of control perfused and treated hearts were reduced and labeled with the light and heavy ICAT reagents, respectively. Protein extracts were mixed in equal amounts and relative proportions of the isotope-labeled peaks were used to quantify oxidative changes between the control and the treated groups. Approximately 300 peptides with ICAT signatures were reliably identified in each sample, with 181 peptides from 118 proteins common to all treatments. A proportion showed elevated ICAT ratios, consistent with reversible thiol oxidation. This was most evident after early reperfusion, with apparent reversal after longer reperfusion. In comparison, there was gradual accumulation of protein carbonyls and loss of GSH with longer reperfusion. Many of the thiol changes were in mitochondrial proteins, including components of electron transport complexes and enzymes involved in lipid metabolism. The results are consistent with mitochondria being a major site of oxidant generation during early cardiac reperfusion and mitochondrial thiol proteins being targets for oxidation.

}, keywords = {Animals, Isotope Labeling, Mass Spectrometry, Mice, Mitochondrial Proteins, Myocardium, Oxidation-Reduction, Proteomics, Reactive Oxygen Species, Reperfusion Injury, Sulfhydryl Compounds}, issn = {1873-4596}, doi = {10.1016/j.freeradbiomed.2013.01.021}, author = {Kumar, Vikas and Kleffmann, Torsten and Hampton, Mark B and Cannell, Mark B and Winterbourn, Christine C} } @article {519, title = {Unexpected histone H3 tail-clipping activity of glutamate dehydrogenase. (Mass spectrometry - Proteomics)}, journal = {J Biol Chem}, volume = {288}, year = {2013}, month = {2013 Jun 28}, pages = {18743-57}, abstract = {

Clipping of histone tails has been reported in several organisms. However, the significance and regulation of histone tail clipping largely remains unclear. According to recent discoveries H3 clipping has been found to be involved in regulation of gene expression and chromatin dynamics. Earlier we had provided evidence of tissue-specific proteolytic processing of histone H3 in White Leghorn chicken liver nuclei. In this study we identify a novel activity of glutamate dehydrogenase (GDH) as a histone H3-specific protease in chicken liver tissue. This protease activity is regulated by divalent ions and thiol-disulfide conversion in vitro. GDH specifically clips H3 in its free as well as chromatin-bound form. Furthermore, we have found an inhibitor that inhibits the H3-clipping activity of GDH. Like previously reported proteases, GDH too may have the potential to regulate/modulate post-translational modifications of histone H3 by removing the N-terminal residues of the histone. In short, our findings identify an unexpected proteolytic activity of GDH specific to histone H3 that is regulated by redox state, ionic concentrations, and a cellular inhibitor in vitro.

}, keywords = {Amino Acid Sequence, Animals, Binding Sites, Brain, Chickens, Chromatin, Cysteine Proteases, Disulfides, Epigenesis, Genetic, Gene Expression Regulation, Enzymologic, Glutamate Dehydrogenase, Histones, Hydrogen-Ion Concentration, Liver, Mass Spectrometry, Mice, Molecular Sequence Data, Rats, Recombinant Proteins, Salts, Sulfhydryl Compounds, Temperature}, issn = {1083-351X}, doi = {10.1074/jbc.M113.462531}, author = {Mandal, Papita and Verma, Naveen and Chauhan, Sakshi and Tomar, Raghuvir S} }