The histone tail extensions constitute up to 30% by mass of histones, but are not visible in the crystal structures of nucleosomes due to their high intrinsic flexibility, and have been thought to be largely unstructured.
As extensión con forma de cola das histonas supoñen o 30% da masa das histonas, pero non son visibles nas estruturas cristalinas do nucleosoma debido á súa grande flexibilidade, e crese que están moi desestructuradas.