The nucleosome core particle: does it have structural and physiologic relevance?

Although the nucleosomal core particle has been extensively studied as the basic building block of chromatin, the biological significance of a unit carrying exactly 146 bp of DNA remains unclear. Herein, we present data to show that the histone octamer can stably accommodate anywhere from about 100 to 170 bp of DNA. The unfolded structures containing less than 146 bp may well be of greater biological importance than the canonical core particle.