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1000
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Abstract/Summary
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Post-translational modifications (PTMs) of histones regulate chromatin structure and function. Because nucleosomes contain two copies each of the four core histones, the establishment of different PTMs on individual ‘sister’ histones in the same nucleosomal context, i.e. asymmetric histone PTMs, are difficult to analyze. Here, we generated differentially isotope-labeled nucleosomes to study asymmetric histone modification crosstalk by time-resolved NMR spectroscopy. Specifically, we delineate mechanistic insights into nucleosomal histone H3 modification reactions in cis and in trans, hence within individual H3 copies, or between them. We validated our approach using the H3S10phK14ac crosstalk mechanism, mediated by Gcn5 acetyltransferase. Moreover, phosphorylation assays on methylated substrates identified Haspin kinase able under certain conditions to produce nucleosomes decorated asymmetrically with two distinct types of PTMs.
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