Isoxazole‐Derived Amino Acids are Bromodomain‐Binding Acetyl‐Lysine Mimics: Incorporation into Histone H4 Peptides and Histone H3 |
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| Authors: | Angelina R Sekirnik&#x; David S Hewings Natalie H Theodoulou Lukass Jursins Katie R Lewendon Laura E Jennings Timothy P C Rooney Tom D Heightman Stuart J Conway |
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| Institution: | 1. http://conway.chem.ox.ac.uk/;2. Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK;3. Nuffield Department of Clinical Medicine, Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Oxford, UK |
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| Abstract: | A range of isoxazole‐containing amino acids was synthesized that displaced acetyl‐lysine‐containing peptides from the BAZ2A, BRD4(1), and BRD9 bromodomains. Three of these amino acids were incorporated into a histone H4‐mimicking peptide and their affinity for BRD4(1) was assessed. Affinities of the isoxazole‐containing peptides are comparable to those of a hyperacetylated histone H4‐mimicking cognate peptide, and demonstrated a dependence on the position at which the unnatural residue was incorporated. An isoxazole‐based alkylating agent was developed to selectively alkylate cysteine residues in situ. Selective monoalkylation of a histone H4‐mimicking peptide, containing a lysine to cysteine residue substitution (K12C), resulted in acetyl‐lysine mimic incorporation, with high affinity for the BRD4 bromodomain. The same technology was used to alkylate a K18C mutant of histone H3. |
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| Keywords: | alkylation amino acids bromodomain electrostatic interactions mass spectrometry protein modifications |
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