Structure and stability of DNA quadruplexes under molecular crowding conditions

A living cell contains generally macromolecules occupying 20-40% of the total volume. To mimic the crowded cellular condition, we prepared solutions including various cosolutes and investigated the influence of the cosolute on the structure and stability of DNA G-quadruplex. As a result, Tetrahymena telomere sequences form well-ordered G-wires in the presence of cosolutes, whereas human telomere sequences remain as compact G-quadruplexes. Since these sequence motif differ by only one base, these results demonstrate that a single base difference in telomere sequences leads to drastically different structures under the molecular crowding conditions. The findings are useful for understanding G-quadruplex structures in cell-like conditions and for design of DNA nanomaterials.