Practice question

Higher order folding beyond beads relies on specific internucleosomal contacts between flexible histone tails and neighboring particle surfaces. Crystallographic and mutational studies show H4 N-terminal tail, especially basic patch residues 16 to 24 including lysine 16 and arginine 19, inserts into acidic patch formed by H2A alpha helices glutamates E56, E61, E64, E92 and H2B. This interaction brings adjacent nucleosomes together during 30 nanometer fiber formation and creates oligomerization interface. Acetylation at H4K16 disrupts binding preventing compaction needed for transcription silencing and dosage compensation regulation in Drosophila males via MSL complex.