Practice question

Linker DNA connecting adjacent nucleosomes constitutes binding site for fifth histone family distinct from core. H1 binds at dyad axis where DNA enters and exits octamer, globular winged-helix domain contacts both linkers while lysine-rich C-terminal tail neutralizes linker DNA charge. Interaction seals nucleosome, determines exit angle and promotes 30 nanometer fiber folding into solenoid or zigzag conformations. Core histones H2A, H2B, H3 remain buried inside octamer forming handshake motifs, not contacting linker extensively. Therefore H1 classifies as linker histone easily extracted at moderate salt 0.5 molar versus core.