DNA repeats and archaeal nucleosome positioning.

Archaeal histones, homologs of the eucaryal nucleosome core histones, have been identified in the Euryarchaeota. They assemble as tetramers with dsDNA to form archaeal nucleosomes that resemble the central structure of the eucaryal nucleosome formed by the histone (H3-H4)2 tetramer. Eucaryal and archaeal nucleosomes assemble preferentially on DNA molecules that best accommodate the severe bends found within these structures, and here we discuss the relationships between archaeal and eucaryal nucleosomes, repeating DNA sequences, and nucleosome positioning.