FIGURE 1.

Schematic showing the construction of higher order human telomeric DNA quadruplexes. (a) Cartoon and (b) stick representations of the construction of the 45-mer from two 21-mer units (cyan and blue), connected together by a TTA loop in a 5′ → 3′ orientation (yellow). Two 45-mer units can be joined by a TTA loop (red) to form a 93-mer. (c) Surface representation of 21-mer, 45-mer, and 93-mer models. The values of rise and rotation between successive G-tetrads results in the generation of grooves (whose direction is indicated by diagonal arrows), which are retained in the higher order models. (d) Top view of model 4 highlighting its propeller-like appearance.