Molecular components of the archaeal nucleosome

Here we describe the organization of the archaeal nucleosome, in which four archaeal histones are circumscribed by similar to 80 bp of DNA. Through a combination of sequence comparisons, 3D structural studies, site-directed m utagenesis and assays for DNA binding, we have assigned functions to most o f the individual residues in the histone fold of the representative archaea l histone rHMfB. By SELEX selection, the sequences of DNA molecules that ar e most readily bound and wrapped by rHMfB into archaeal nucleosomes in vitr o have been identified, and these define DNA structures that position archa eal nucleosome assembly. (C) 2001 Societe francaise de biochimie et biologi e moleculaire / Editions scientifiques et medicales Elsevier SAS.