The reassociation with chromatin of H1 fragments bisected with thrombin

When fragments of H1 histone formed by bisection of H1 histone with thrombin were allowed to reassociate with H1 histone-depleted chromatin, the carboxyl-terminal segment reassociated in such a manner as to protect the micrococcal nuclease-sensitive site(s) of the nucleosome core. On the other hand, the NH2-terminal segment of H1 histone protected 20 base pairs of linker DNA adjacent to the nucleosome core particle. These data provide strong evidence that the NH2-terminal portion and the carboxyl-terminal portion of H1 histone interact with 20 base pairs of linker DNA and the core DNA of the nucleosome, respectively.