Practice question

High resolution nucleosome structure at 2.8 angstrom shows histone tails exit core not through gaps at sides but threading between DNA gyres through channels formed where minor grooves face octamer. At specific superhelical locations DNA grooves widen permitting basic tails to protrude without disrupting tight histone-DNA wrapping mediated by arginine anchors. Tail emergence through minor groove allows enzymes like GCN5 acetyltransferase and kinases access for modification while maintaining core stability. Major groove exit would clash with phosphate backbone, linker DNA path distinct from tail path. Thus tails emerge via minor groove regions.