Figure 2.

UV/Vis data for the TMPyP4 titration of the annealed Bcl-2 3:7:1 loop isomer mutant sequence. The data are indicative of a strong interaction between TMPyP4 and the Bcl-2 model quadruplex. The titration of the 3:7:1 loop isomer exhibits a sharp isobestic point at 434 nm. Titrations for the WT and the 3:5:3 loop isomer sequence quadruplexes exhibit blurred isobestic points ranging from 433 to 436 nm (see Table 1).