Practice question

Crystallography at 2.8 angstrom resolution reveals 146 to 147 base pairs of B-form DNA make 1.65 left-handed superhelical turns around histone octamer, contacting fourteen arginine anchors inserted into minor grooves. Phosphate backbone sharply bent every 10 base pairs. Earlier digestion estimated about 146 base pairs resistant to micrococcal nuclease. Values of 120 base pairs underrepresent protection, 167 includes linker DNA bound by H1 forming chromatosome, 200 equals full repeat including variable linker. This precise length accounts for linking number change of minus 1.2 per nucleosome enabling topological assays.