Figure 6.
Heat-induced reversible folding and unfolding of a (G3T)2 quadruplex at constant temperature, 70°C, monitored by light absorption. Folding and unfolding was achieved by removing the optical cell from the UV spectrometer and incubating the cuvette at 45°C for 3 min to achieve the initial ON state. The cell was returned to the cell holder and following a 2 min equilibration to reach the reaction temperature of 70°C, the UV absorption was recorded for 10–15 min. The OFF state was then achieved by removing the cell and incubating the sample at 95°C for 3 min. The measurement was continued after returning the cell into the cell holder and equilibrating for 2 min to reach the reaction temperature of 70°C. This procedure was repeated a total of eight times. To see this figure in color, go online.