Fig. 6.

Conformational switching of human telomeric DNA with FRET. (A) Extreme conformational diversity revealed by single-molecule dynamics: representative FRET time traces of single molecules at 2 mM K⁺ and room temperature (0.9 s integration time). (B) Time traces (0.1 s integration time) of donor and acceptor intensities and corresponding FRET from a single molecule at 2 mM K⁺ exhibit interconversion between U, F1, and F2. A transition to zero FRET at 65 s is due to Cy5 blinking. Note that the transition from F2 to F1 occurred through U. Copyright (2005) National Academy of Sciences of the United States of America [58].