| Autor: |
Perell GT; Department of Chemistry, University of Minnesota , 207 Pleasant Street Southeast, Minneapolis, Minnesota 55455, United States., Mishra NK; Department of Chemistry, University of Minnesota , 207 Pleasant Street Southeast, Minneapolis, Minnesota 55455, United States., Sudhamalla B; Department of Chemistry, University of Pittsburgh , 1307 Chevron Science Center, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States., Ycas PD; Department of Chemistry, University of Minnesota , 207 Pleasant Street Southeast, Minneapolis, Minnesota 55455, United States., Islam K; Department of Chemistry, University of Pittsburgh , 1307 Chevron Science Center, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States., Pomerantz WCK; Department of Chemistry, University of Minnesota , 207 Pleasant Street Southeast, Minneapolis, Minnesota 55455, United States. |
| Abstrakt: |
Post-translational lysine acetylation of histone tails affects both chromatin accessibility and recruitment of multifunctional bromodomain-containing proteins for modulating transcription. The bromodomain- and PHD finger-containing transcription factor (BPTF) regulates transcription but has also been implicated in high gene expression levels in a variety of cancers. In this report, the histone variant H2A.Z, which replaces H2A in chromatin, is evaluated for its affinity for BPTF with a specific recognition pattern of acetylated lysine residues of the N-terminal tail region. Although BPTF immunoprecipitates H2A.Z-containing nucleosomes, a direct interaction with its bromodomain has not been reported. Using protein-observed fluorine nuclear magnetic resonance (PrOF NMR) spectroscopy, we identified a diacetylation of H2A.Z on lysine residues 4 and 11, with the highest affinity for BPTF with a K d of 780 μM. A combination of subsequent 1 H NMR Carr-Purcell-Meiboom-Gill experiments and photo-cross-linking further confirmed the specificity of the diacetylation pattern at lysines 4 and 11. Because of an adjacent PHD domain, this transient interaction may contribute to a higher-affinity bivalent interaction. Further evaluation of specificity toward a set of bromodomains, including two BET bromodomains (Brd4 and BrdT) and two Plasmodium falciparum bromodomains, resulted in one midmicromolar affinity binder, PfGCN5 (K d = 650 μM). With these biochemical experiments, we have identified a direct interaction of histone H2A.Z with bromodomains with a specific acetylation pattern that further supports the role of H2A.Z in epigenetic regulation. |
