Practice question

Lysine acetylation directly weakens histone-DNA electrostatic attraction. Transfer of acetyl from acetyl-CoA to ε-amino group removes positive charge, reducing net basic character of tail and diminishing binding to phosphate backbone. Structural studies reveal increased tail disorder, enhanced nucleosome breathing and greater accessibility for transcription factors. Bromodomain proteins further recognize acetyl-lysine, recruiting remodelers that slide or eject nucleosomes. Functionally, hyperacetylation at promoters and enhancers correlates with euchromatin formation, while deacetylation restores compaction. This biophysical effect distinguishes acetylation from methylation that preserves charge.