Oxidation metabolism generates a multitude of products including bifunctional electrophiles. We have developed a global strategy for identifying the protein targets of bifunctional electrophiles using alkyne-tagged electrophiles and click chemistry to attach biotin linkers to adducted proteins post-hoc. Quantifying peptide counts from digests of streptavidin-enriched protein mixtures identifies the most reactive proteins among the many that bear adducts. Bioinformatic analysis of these data sets and integration with microarray or RNA-seq data sets from treated cells enables construction of networks relating protein modification, signal transduction and transcriptional activation/inhibition. This identified key pathways of cellular response to lipid electrophiles including protein targets triggering transcriptional changes.<br/><br/>An important class of targets of modification by bifunctional electrophiles are histones, the major structural proteins of chromatin and important sites of epigenetic regulation. We have developed a quantitative method for analysis of arginine and lysine modification (QuaRKMod), which reveals many modifications beyond acetyllysine and trimethyllysine including modifications by the bifunctional electrophiles, 4-oxo-nonenal and methylglyoxal. Application of QuaRKMod to histone samples from basal cells or cells stimulated to carry out oxidative metabolism reveals the presence of histone adducts at levels comparable to canonical adducts that regulate gene expression. Adducts from bifunctional electrophiles may link metabolism and epigenetic regulation.<br/>

Histone modification by bifunctional electrophiles derived from lipid and carbohydrate metabolism

2019 Fall National Meeting

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