Practice question

Structural biology consensus derived from multiple crystal forms and cryoEM shows nucleosome core particle wraps 146 to 147 base pairs of DNA in 1.65 left-handed superhelical turns around histone octamer disc, creating 14 minor groove contacts. Early nuclease protection assays estimated 146 base pairs resistant to micrococcal digestion. Chromatosome including H1 adds twenty base pairs bringing protection to 167 base pairs. Values 120 base pairs underrepresent wrapped length, 200 equals full repeat with linker, 33 base pairs corresponds roughly to single superhelical turn. This conserved length reflects requirement to bend DNA around octamer while exposing tails for regulation across eukaryotes.