Structure of the yeast nucleosome core particle reveals fundamental changes in internucleosome interactions

Chromatin is composed of nucleosomes, the universally repeating protein-DNA complex in eukaryotic cells. The crystal structure of the nucleosome core particle from Saccharomyces cerevisiae reveals that the structure and funct ion of this fundamental complex is conserved between single-cell organisms and metazoans. Our results show that yeast nucleosomes are likely to be sub tly destabilized as compared with nucleosomes from higher eukaryotes, consi stent with the idea that much of the yeast genome remains constitutively op en during much of its life cycle. Importantly, minor sequence variations le ad to dramatic changes in the way in which nucleosomes pack against each ot her within the crystal lattice. This has important implications for our und erstanding of the formation of higher order chromatin structure and its mod ulation by post-translational modifications. Finally, the yeast nucleosome core particle provides a structural context by which to interpret genetic d ata obtained from yeast. Coordinates have been deposited with the Protein D ata Bank under accession number 1ID3.