Figure 7.

Loop conformations in the Tel26 quadruplex in K⁺ solution. (A) Stereo views of the first TTA loop (T7–T8–A9) which adopts a double-chain-reversal loop conformation. (B) Loop interactions with the top G-tetrad. The unique adenine triple capping structure is shown. The third T19–T20–A21 lateral loop is also shown. (C) Loop interactions with the bottom G-tetrad. The second T13–T14–A15 lateral loop is shown. The loop adenines are in red, while the loop thymines are in green. The top G-tetrad (as in Figure 1C) is in cyan, the middle G-tetrad is in magenta and the bottom G-tetrad is in blue.