<p>Histone H3 is one of the four histones, along with H2A, H2B and H4, whichform the eukaryotic nucleosome octomer core [<cite idref="PUB00004448"/>];the nucleosome octamer winds ~146 DNA base-pairs. It is a highly conserved protein of 135amino acid residues [<cite idref="PUB00004448"/>, <cite idref="PUB00004388"/>].</p><p>Several proteins have been found to contain a C-terminal H3-like domain,including the mammalian centromeric protein CENP-A (which may act as a corehistone necessary for the assembly of centromeres) [<cite idref="PUB00003077"/>]; yeast chromatin-associated protein CSE4 [<cite idref="PUB00001924"/>]; and <taxon tax_id="6239">Caenorhabditis elegans</taxon> chromosome III proteins YL82_CAEEL and YMH3_CAEEL, whose function is unknown.</p>