Isoxazole-Derived Amino Acids are Bromodomain-Binding Acetyl-Lysine Mimics: Incorporation into Histone H4 Peptides and Histone H3.
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.
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
Angelina R
AR
Sekirnik Née Measures
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
David S
DS
Hewings
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
Natalie H
NH
Theodoulou
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
Lukass
L
Jursins
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
Katie R
KR
Lewendon
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
Laura E
LE
Jennings
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
Timothy P C
TP
Rooney
Nuffield Department of Clinical Medicine, Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK.
Tom D
TD
Heightman
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK. stuart.conway@chem.ox.ac.uk.
Stuart J
0000-0002-5148-117X
SJ
Conway
alkylation; amino acids; bromodomain; electrostatic interactions; mass spectrometry; protein modifications