Oligoadenosine tracts favor nucleosome formation.

We have measured the ability of oligoadenosine tracts 25 base pairs in length to influence nucleosome formation. Such tracts can cause DNA to bind in nucleosomes at higher temperatures with a free energy up to 1 kcal/mol more favorable than heterogenous-sequence DNA. Furthermore, the position of the oligoadenosine tract affects the free energy of binding, with the most favorable position occurring at the dyad axis.